icawww > '^ « cC Rcc : ore oCC C CCC ca u c ;cc c «c c c _L< Cdec cc ccrc cccc c c c- cC CL CC Oc C Kolo o or ccC< CCcc ;-CC < ;-CC c CCC c 0» C*CcC C - C- -), Inspection of the formula for s will show that, for any year from 1700 A. D. New Style to 1899 A. D., both inclusive, the value of s is zero (0). For any year Old Style the value of s is the con- stant number 22. /23 + s -f- 19 n\q=[ 30 j r ;also, /23-f 5-ll7l\ -V 30 ) r »-(a).+*=i(A).(n). 16 PHILOSOPHICAL SOCIETY OF WASHINGTON. The value of h may be shown to be zero (0) for any year from 1700 A. D. to 1899 A.. D., both inclusive, during New Style, and for all years during Old Style. p = q — h = the interval in days from March 21st to the date of the Paschal full moon, or the number of days to be added to March 21st to find the date of the Paschal full moon. If p = zero (0), the Paschal full moon accordingly falls on the 21st of March. j.( l + »(T) r -»-(i).+ fe).) L denotes the number (in alphabetical order) of the Dominical or Sunday letter. Thus, the number corresponding to the Domini- cal letter A is 1, to B is 2, to C is 3, to D is 4, to E is 5, to F is 6, and to G is 7 or (zero). The term ( tq ) gives a correction to the Gregorian value when the year exceeds 4000 A. D. ; for any year less than 4000 the value of this corrective term is obviously zero (0). ,_i_(!=ft£) f -(Lt^±^ i t denotes the number of days which elapse after the date of the Paschal full moon to the date of Easter Sunday. Easter Sunday = March (21 + 1 + p 4- 1 — 1) = March (21 + p + t) = April (p + t — 10) To find the date of Easter Sunday for any year, A. D., Old Style. /year\ /100 c -\-y\ n =\-W) r =K—W-) r The formula for n is the same as in New Style. /23 4-22 + 19 n\ ( lb + 19 n\ /15 — 11 n\ <*= P = { 30 ) t - I 30^ A - V 30 ) r £=( 8 + «-y-(i)w ) ^ 1 = (l=^) r l(i±^LX) r GENERAL MEETING. 17 Easter Sunday = March (21 + 1 + p + t — 1) = March (21+ja + f) = April (jp + t — 10) ' Example 1. — Required the day of the month on which Easter Sunday falls in the year 1883 A. D., New Style. Q r = 18or-l ; 5(i|) p = 90oi-S . ©. -(**£")-» n =-5 + 7 = 2 20 n = 40 19 n = 20 n — n = 38 .-K^-ftV(M+1 -f^). )_ = 10-4- (~i~ ) w = 10-4-6 = /23 + s + 19 »\ /'23 + + 38\ * - V 30 J r - I 30 ) t " X A =(219) w+ 2^- I (i) w (n) w= + 28 x°xo=o+o = o _ /I + 2 X 2 — 83 — 20 + \ _ / l + 4 — 6 — 6 \ t - 1 = (-fi) r =(-i±i) r: / •Easter Sunday = March (21 + 1+^ + ^—1) = March (22 + 1 + 2) = March 25 18 PHILOSOPHICAL SOCIETY OP WASHINGTON. Example 2.—Required the date of Easter Sunday for the year 1884 A. D., New Style. 5 m -_ ( 84=« 20 n=8— 5=3 20 w = 60 20 — n= 19 n — 57 s = _ / 23 + + 57 \ »-©.%=* (l),(n). =0+9x0X0=0+0=0 p = g-/i = 20-0 = 20 x = ( * + »(¥),-"-(?).+ Q. ) .( 1 + 4 -?- 0+0) r -6 ( _ 1=(3^±5)r : (^)r=2 Easter Sunday = March (21 + 1 + 20 + 2) = March 44 = April (44 — 31) = April 13 Example 3. — Required date of Easter Sunday for the year 3966 A. D., New Style. 39 1 66 2X 19 = 38 | 57 = 3X19 1 I 9 c-tfve-^pv* 20 n = 280 19 n = 20 n — n = 266 GENERAL MEETING. 19 t=3^-(f)„-(^TT-m,.) = 31 - 9 - ( 3 *) — 31 - 9 - 13 = 9 ? - I 30 J r = I 30 J r = 28 =0+lXl Xl=0+l=l p=2_/i=28 — 1 = 27 £= / 1 + 2 (-) r _ 6e_(^ + (|)X / l + 2x3-3-2 + \ =2 Easter Sunday = March (21 + 1 + 27 + 6) = March 55 = April (55 — 31 =) 24 Example 4. — Required the date of the Paschal full moon {March 21 + p), and the date of Easter Sunday (March 21 + p + t or March 21 + 1 +p + (t — 1) for the year 2152 A. D., New Style. /2152\ 19 n= 95 s= 1 23= 23 19n + s+23 = 119 r(giyg),-(ii),-' ^=1+0x0x0= 1 p=q — h= 28 20 PHILOSOPHICAL SOCIETY OF WASHINGTON. Pascbal full moon — March (21 + 28 =) 49 = April (49 -31=) 18 z-( * + 'ffl,-»-(?).+ (S). ) /! -f 2~xT— 52 — 13 + \ Easter Sunday = March (21 + 1 + 28 + 4 =) 54 = April (54 -31=) 23 The Julian or Old Style Calendar was established by the Council of Nice A. D. 325 ; the first year of the Gregorian or reformed calendar was A. D. 1582, and the first year in which the reformed calendar was adopted in England was A. D. 1752. In Russia, and in other countries where the religion of the Greek Church now obtains, the New Style of reckoning has not been adopted, but the Old Style is still in force. In Alaska, Old Style was employed until after the cession of that country by Russia to the United States in the year 1869. Example 5. — Find the date of Easter Sunday for the year 1582 A. D., Old Style. 15 | 82 5-f- 15 | =75 20-1) 157 * (7 140 - 7 17 + 7 = 24 = 19 -f- 5 n = 5 19 n = (20— 1) n = 100 — 5 = 95 = 3 X«30 + 5 /19n + 15\ /5 + 15\ /3 + 15 - 82 - 20\ = (18^6X=(18-nx = GENERAL MEETING. 21 '3 - 20 + 0> -'-m,- Easter Sunday = March (22 -f 20 -f 4 =) 46 = April (46 - 31 =) 15 232d Meeting. March 24, 1883. "Vice-President Welling in the Chair. Forty-three members and visitors present. The first communication was by Mr. J. R. Eastman on THE FLORIDA EXPEDITION FOR OBSERVATION OF THE TRANSIT OF VENUS. [Abstract. ] The observing station of the Florida expedition was upon Way Key, the largest of the group of islands known as Cedar Keys. The principal instruments employed were a portable transit, a five-inch equatorial telescope, and a photoheliograph. The first two require no description. The photoheliograph consisted of an objective of five inches aperture and about forty feet focus, a helio- stat for throwing the sun's rays on the objective, and a plate holder at the focus of the objective. The accessory apparatus consisted of a measuring rod, permanently mounted, for accurately measuring the distance from the objective to the photograph plate ; a movable slide with a slit of adjustable width, for exposing the plates; and a circuit connecting with a chronograph, so arranged that when the exposing slide was moved to expose the plate, and when the center of the slit was opposite the center of the plate-holder, the circuit was broken and the record made on the chronograph. A black disk was painted on one side of the slide, and so placed that when the slide was at rest at one end of its course and the image of the sun was adjusted concentric with this disk, it would fall on the center of the plate-holder when the slide was moved. The adjust- ments having been completed the exposing of the plates was a sim- ple matter. The image of the sun was thrown by the heliostat upon the black disk and centered, the sensitive plate was fixed in 22 PHILOSOPHICAL SOCIETY OF WASHINGTON. the plate-holder, the operator moved the exposing slide, and the time of exposure was recorded on the chronograph. For observing contacts I used an eye piece, magnifying 216 diam- eters, attached to a Herschel solar prism, and a sliding shade-glass with a density varying uniformly from end to end. The time of my signals was taken by assistant astronomer Lieut. J. A. Norris, U. S. N., from a chronometer ; while, with an observing key, I also made a record on the chronograph as a check. About 40 seconds before the computed time of first contact a narrow stratus cloud passed on to the southeastern edge of the sun and shut out all the light. The cloud remained about 3 minutes, and when it passed off, the notch in the sun's limb was plainly marked. Two photographs were taken to test the apparatus and the plates, and then the time before second contact was devoted to an examination of the limbs of Venus and the sun. Both were perfectly steady. In observations of the sun for the last twenty years I never saw it better. At about 13 minutes after first contact the outline of the entire disk of Venus could be seen, and seemed perfectly circular. About 2 minutes later a faint, thin rim of yellowish light appeared around the limb yet outside the sun. This rim was at first broadest near the sun's limb, but soon the width of the light became uniform throughout. The light was wholly ex- terior to the limb of Venus ; that is, the black limb of Venus on the sun and the dark limb outside formed a perfectly circular disk, with the rim of light or halo, outside the portion off the sun. As the time of second contact approached, Lieutenant Norris again took up his station at the chronometer. As the limbs neared geo- metrical contact, the cusps of sunlight began to close around Venus more rapidly; and the perfect definition of the limbs and the steady, deliberate, but uniformly increasing motion of the cusps, convinced me instantly that the phenomena attending the contact would be far more simple than I had ever imagined. I had only to look steadily to see the cusps steadily but rapidly extend themselves into the thinnest visible thread of light around the following limb of Venus and remain there without a tremor or pulsation. At the moment the cusps joined I gave the signal and also made the record on the chronograph. Still keeping my eye at the telescope, I saw nothing to note save the gradually increasing line of light between the limbs of the two bodies. The disk of Venus on the sun was black. GENERAL MEETING. 23 A re-examination was then made of all the photographic appara- tus, and about 10 minutes after the second contact the principal photographic work was commenced ; and this was continued with slight interruption until about 10 minutes before third contact; 150 dry plates and 30 wet ones being exposed. One of the inter- ruptions was for the purpose of making measurements of the diameter of Venus, which was done with a double-image micrometer attached to the 5-inch telescope. On going to the telescope to observe the last contacts, I found the limbs of Venus and the sun as steady as in the morning, and though there was now some haze over the sun it did no harm. The. third contact was observed with great accuracy, nothing occurring to obstruct or complicate the very simple and definite phenomena, which were in the reverse order of those seen at second contact. The rim of light appeared around Venus as soon as the limb was visible beyond the sun, and was seen for nearly 10 minutes. The complete outline of Venus was visible for 2 minutes longer. No phenomena worthy of note were seen between third and fourth con- tacts. The lapping of the limb of Venus over that of the sun gradually but steadily decreased until the final separation, which was observed with great accuracy for such a phenomenon. Soon after the last contact the entire apparatus was again carefully examined and the necessary observations made to determine the errors of the chronometers. In the observations of interior contacts there was no trace of any tremor or fluctuation of the light in the cusps as they closed around the limb of Venus ; and it is almost needless to say that there was no trace of a shadow or a black drop or ligament between the limbs at second and third contacts. The probable error for the second and third contacts was estimated at 0".3 ; for fourth con- tact, 0".5. Observers of transits of Venus and Mercury have written so much in regard to the obstacles encountered from the apparition of the shadow, or black drop, between the limbs of the two bodies at second and third contacts, and so full has been the testimony in favor of the existence and the almost necessary occurrence of this phenomenon, that at the transit of Mercury, in 1878, many ob- servers claimed, as evidence of their skill, that they did see it ; while others, less fortunate, apologized for not seeing it. Observers of the black drop were so generally confined to those with imperfect 24 PHILOSOPHICAL SOCIETY OF WASHINGTON. apparatus or to those unaccustomed to observation of the sun's limb or disk that the true nature of the obstacle was pretty well understood before it was carefully investigated. It is now quite well settled that the " black drop " is due to bad eyes, imperfect apparatus, or the inexperience of the observer. With good eyes and proper apparatus a good observer never should see the black drop. When it is seen there is something wrong ; it is a spurious phenomenon. One of the negatives was exhibited to the Society. In reply to a question by Mr. E. J. Farquhar, Mr. Eastman said the halo about Venus was believed to be due to the atmosphere of the planet. The next communication was by Mr. Cleveland Abbe on DETERMINING THE TEMPERATURE OF THE AIR. He stated that the question now to be considered is not where to place a thermometer so as to obtain the temperature most proper for the use of the meteorologist, but is rather the purely physical question of how to determine the temperature of the air at any given location. He described the methods and defects of the for- mer and present meteorological methods of exposure, viz : (1) Ther- mometers hung in the open air. (2) Those placed in shady loca- tions. (3) The Glaisher screen. (4) The Stevenson screen and the double louvre screens in general. (5) The double metallic cylin- drical shelters of Jelinek and Wild. (6) The silver thimble screen of Regnault. (7) The whirling thermometer of Saussure, Arago, Bravais, and the French observers (exhibiting Babinet's arrange- ment as made by Casella.) (8) Joule's method, depending on a balance in the temperature and density of two columns of the air. He then gave a description of the method devised by him in 1865 and used for a short time at Poulkova; this consisted in con- structing a very perfect louvre screen, within which were established black bulb and bright or silvered bulb thermometers having very diverse coefficients of radiation and conduction. These thermom- eters were in air, not in vacuo, as this latter arrangement was proper only for the determination of the direct solar radiation, as in the Arago-Davy method, whereas in the present case the temperature of the air and the radiation from terrestrial objects were the special objects of study. GENERAL MEETING. 25 The air temperature (ta ) was found from the indications of the bright and black bulbs (t 8 and tb) by the empirical formula ta =te + C(tb— t s) where C is a small coefficient, to be determined experimentally, and is nearly constant. This arrangement of bright and black bulbs can be used by meteorologists and physicists without a screen, and even in the sunlight, if the. theory of the action of the bright and black bulbs is perfectly understood. A similar for- mula will give the temperature (T) of a single radiating body whose effect is equal to the total effect that is shown by the black bulb : T= tb + C'(tb— ts.) He then stated that the theoretical basis of this method has quite recently been further elucidated by Professor Ferrel, who has shown that the approximate nature of the relation between the above con- stant C, the radiating, absorbing, and conducting powers of the thermometers, and the velocity of the wind is given by the following equation : „ 1+ B'+ B"v \j— where rb and rs are the radiating (and absorbing) powers of the blackened and silvered bulbs, respectively, v is the velocity of the wind or currents flowing past the bulbs, and B B' B" are constant coefficients depending on the size, conductivity, and specific heat of the substance of the bulbs. In reply to a question of Mr. Gilbert, he stated that the differ- ence between the bright and black bulbs had rarely exceeded a few tenths of a degree in the delicate shelter made of oiled paper, as used by him at Poulkova, the maximum occurring February 22, 1866, at 10 a. m., when, the louvre box being in the full sunshine, the bright bulb was at 14°.9 Cent, and the black bulb at 14°. 3, showing that the latter had been slightly warmed by the warm sides of the box. In reply to a question of Mr. Harkness, the author explained, that although it was conducive to accuracy that these thermometers should be placed within a shelter, yet this was not necessary ; if we take advantage of the more accurate method of determining 26 PHILOSOPHICAL SOCIETY OF WASHINGTON. the co-efficient constant C, as given by Prof. Ferrel's theory, the two thermometers placed anywhere within doors or without would still give data for determining temperatures of the loca- tion ; it should be borne in mind that the temperature thus ob- tained belongs specifically to the air in contact with the themome- ters and is not an average value for any extensive portion of the atmosphere. As it is an advantage to conduct observations under uniform conditions, it is recommended that a pair of bright and black bulb thermometers be attached to the whirling table, whereby the effect of a current of air may be on the one hand determined and on the other hand kept as uniform as possible. Mr. Harkness said that the object practically sought by meteo- rologists was to learn the average temperature of a considerable body of air, but their efforts were thwarted by the irregularity and inconstancy of the distribution of temperature. So long as the air in contact with the thermometer is not precisely representative of the air of the vicinage it was useless to refine methods of observa- tion, unless by that refinement errors of a constant nature were eliminated. For the determination of mean monthly or annual temperatures he considered the reading of the nearest half degree as sufficient, and regarded the reading of the tenths of a degree as a useless refinement. The advantage of reading to tenths was further discussed by Messrs. Abbe, Doolittle, and Kummell. Mr. Kummell pointed out that where a difference of temperature is observed as an indication of the moisture of the air, the tenths are worthy of record. The following communication by Prof. Charles E. Munroe, of Annapolis, Md.g was then read by the Secretary : DETERMINATION OF THE SPECIFIC GRAVITY OF SOLIDS BY THE COMMON HYDROMETER. Having occasion some time since to devise methods for the ex- amination of coal on board ship, I was obliged, as my first con- sideration, to work with such materials and apparatus as are usually found in ships' stores, and then to arrange the methods so that they could be used under the restricted conditions which prevail. The unsteadiness of the ship makes balance methods for the determina- tion of specific gravities difficult, even when a suitable balance is at GENERAL MEETING. 27 hand, while hydrometers may be steadied so that the instrument may be read with a reasonable degree of precision, as is shown in its constant use in the determination of the degree of saturation of the water in the steam-boiler, and in other instances. To use the hydrometer for the determination of the specific gravities of solids I take advantage of the fact that, when a body floats in a liquid in which it is wholly immersed, the specific gravi- ties of the liquid and the solid are the same, and we have simply to determine the value for one of them. The process is carried out by taking a dense solution, dropping in it the solid to be determined, (which must be light enough to float on the surface,) and then diluting slowly with water until the solid floats immersed, stirring the mixture constantly. The solid is now removed and the hydrometer inserted and read. For the determination of the specific gravities of the bituminous coals and lignites a thick solution of cane sugar was used, while for the heavier anthracite concentrated sulphuric acid, diluted with dilute sulphuric acid, was employed. The increase in temperature in the latter case causes no appreciable error if the reading is quickly taken. The following results were obtained by the method des- cribed, the specific gravity of each specimeu having first been de- termined by Jolly's balance : By Jolly's balance. By mixture. Anthracite 1.5640 1,560 Bituminous coal 1,3008 1,310 Bituminous coal 1,3000 1,300 Gas coal 1,2790 1,285 Cannel coal (ligniform) I > 1 55° I > 1 55 Cannel coal 1,1292 1,120 Lignite 1,0909 1,090 Mr. Dutton remarked that the same principle had recently been successfully applied to the separation of the component minerals of crystalline rocks. A sample is powdered and then placed in a very heavy liquid (a solution of mercuric iodide and potassium iodide), the density of which is gradually diminished, until the particles of the heaviest mineral sink to the bottom. A repetition of the process eliminates each mineral in turn. 28 PHILOSOPHICAL SOCIETY OF WASHINGTON. 233d Meeting. April 7, 1883. Mr. Wm. H. Dall in the Chair. Thirty-six members and visitors present. The Chair announced that Messrs. Edward Sandpord Burgess and Sumner Homer Bodfish had been elected members. The General Committee reported to the Society that " a Mathe- matical Section had been organized by the election of Mr. Asaph Hall as Chairman and Mr. Henry Farquhar as Secretary. All members of the Society who are interested in mathematics are in- vited to attend and take part in its meetings, announcements of which will be sent to those who notify the Secretary of a desire for them." The first communication was by Prof. W. C. Kerr on THE GEOLOGY OF HATTERAS AND THE NEIGHBORING COAST. [Abstract.] The notable projection of Hatteras, beyond the general line of trend of the Atlantic coast, has, of course, a geological origin. The study of the changes now taking place, and of the phenomena which have left their recent traces on the surface, readily furnish the data for the solution of the problem. Nearly one-half of this eastern inter-sound region of North Carolina is water surface, and the land surface lies for the most part below ten feet (much of it below five.) A large part of this low-lying surface is covered with beds of peat, which thicken towards the centre on the divides or swells be- tween the bays and sounds, rising, in some cases, to ten and fifteen feet, and in the Dismal Swamp on the northern border of the State to twenty-two feet. These beds of peat are in process of forming by the decay of plants growing on the surface, chiefly cypress and juniper. Many tiers of the undecayed logs of these timbers are piled upon one another through the whole thickness of the deposit, which is soft and yielding, so that a fence-rail may be thrust down beyond its length. Vast tracts of such peat swamps (and of marsh and savanna on which only water grasses and small shrubs and scrub pines grow and decay) are found throughout this coast region. Here we have the first stage in the formation of a coal bed. Another notable fact is that many of the rivers which empty into the sounds GENERAL MEETING. 29 increase in depth of channel at a distance from their mouths ; while the sounds are 12 to 15 and 20 to 22 feet deep, the rivers are often 30 and 40 feet and upwards. This can only be accounted for by supposing a subsidence of the region to be in progress, the sounds and open bays being silted up by the deposits brought down by the floods of the Roanoake and other large rivers, while no particle of sediment can reach the sheltered depths of the narrow windings of the upper reaches of these minor streams. This theory of subsidence is abundantly confirmed by the disappearance under water of large tracts of swamp bordering the rivers, as the Chowan, within the observation of men now living, and by the existence of rooted stumps of cypress and juniper in the bottom of the bays and sounds, even to the depth of 15 and 20 feet, and also by the vertical and crumbling shores of the sounds, undermined and eroded by the advancing waves. The Atlantic ocean is walled off from this region by a narrow fringe of sand islands, or dunes, blown shoreward by the wind and thrown up into reefs and hillocks like snow-drifts 50, 80, and even more than 100 feet high. The movement of these sand .waves being inland, the sounds are silting up next the sea, and are in many places converted into marshes 3 to 5 miles wide. The reef is increasing in continuity and breadth, most of the inlets above Hat- teras that were open 300 years ago being closed and obliterated. An inspection of the form of the curves of the submarine contours off Hatteras and adjoining coasts will show that the action of the tides and ocean currents, the Gulf stream and Arctic current meet- ing at this point, accumulate upon Hatteras the river silt which reaches the sea by way of the Chesapeake as well as that of the rivers which discharge their burdens through the inlets about this point and southwards. Which amounts to this—that Hatteras may be described as a sort of delta, whose materials are derived from the drainage of more than 100,000 square miles of the Atlantic slope. A subsidence of about 20 feet would bring the sea again over the entire Sound region and carry the shore 75 miles inland, bringing Hatteras to coincide with Cape Lookout. A sand reef, like that north of Hatteras, marks the line of the ancient shore, when these conditions obtained. A depression of fifty feet would move the shore 100 miles west of Hatteras and carry the point of meeting of the conflicting ocean currents and waves to Cape Fear. A subsidence of 500 feet, as in the glacial period, would carry 30 PHILOSOPHICAL SOCIETY OF WASHINGTON. Hatteras more than 200 miles west of its preseut position. This horizon is marked by an immense saud reef, still retaining its wind and wave marks, and rising to a height of more than 500 feet above tide, the reef itself being at least 100 feet deep and many miles in length. The sea must have remained at this level for a very long period. But Hatteras is not a modern phenomenon. It is at least as old as the cretaceous; the quaternary as well as the tertiary of this coast region of North Carolina are laid down upon an eroded surface of cretaceous rock, while the artesian borings, at Charleston, reach this formation at 700 feet, and at the mouth of the Chesa- peake they do not seem to have touched it at 1,000 feet. Mr. Ward remarked that, in traversing the Jericho canal of the Dismal Swamp in a row boat, he had observed an outward flow at both ends of the canal, showing that, by continuous water passage, a divide was crossed between Lake Drummond and the James river. He criticised the doctrine taught in text-books aud popular writ- ings that the preservation of leaves in a fossil state is due ordinarily to river action and delta formation. More favorable conditions are to be found in swamps. Other remarks were made by Messrs. Dutton and Hough. The second communication was by Mr. H. F. Walling on TOPOGRAPHICAL INDICATIONS OF A FAULT NEAR HARPER'S FERRY. [Abstract.] A description was given of a break in the continuity of the Blue Ridge, where its disconnected portions, extending side by side for a few miles, are cut by the Potomac river, near Harper's Ferry, the gorges so formed presenting a striking feature of the scenery. The two ridges, here about 12,000 feet apart, stretch for hundreds of miles in nearly parallel directions, one to the south and the other to the north ; the latter being known in Pennsylvania as the South Mountain. The strike of the rocks is parallel to the ridges, about N. 30° E., and the prevailing dip is eastward* averaging not more than 30°. The ridges are composed of hard sand-rock; the adjacent region, of lime-stone and other rocks more easily dis- integrated or dissolved. Supposing the sand-rock of the Blue Ridge and South Mountains to have been originally a continuous formation, it will be readily GENERAL MEETING. 31 seen that a vertical fault in easterly dipping strata, having its direction somewhat nearer the meridian than the present strike and its downthrow on the west side of the fault, would produce a lateral discontinuity like that here observed, the upthrown part of any stratum cropping out on the east of the downthrown part at a distance depending upon the amount of the vertical displacement. All this would depend upon whether the sand rocks were origi- nally continuous in the two ridges—a question which was left for the geologists to decide. The writer, however, took occasion to suggest that great longitudinal faults might be formed near coast lines when the gradual overloading of the balanced crust by depo- sitions of sediment produced a strain too great to be relieved by flex- ure. A rupture would then occur, the strata going • down on the overloaded side of the fault and up on the other until equilibrium of pressure upon the yielding magma below was restored by lateral displacement of the magma. The fault so formed would present a diminished resistance to dislocation, and if the action which origi- nated it should continue, it would be likely to increase in dimensions both in length and in the amount of vertical displacement. This action might even continue after the emergence of the region above the surface of the water, provided a more rapid denudation of the landward than of the seaward side of the fault took place, in which case a continued disturbance of equilibrium would be accompanied by vertical yielding, increasing the amount of dislocation, and by sub- terranean movements of the supporting magma, whereby a restora- tion of material would be effected from overloaded to denuded areas. Moreover, the hypothesis of a constant restoration of disturbed equilibrium makes it easier to understand why the folding of strata should grow steeper, even to a, folding under, as the axis of a moun- tain chain is approached. A diagram exhibiting the so-called " fan-like structure of the Alps," enlarged from a figure by Rogers, (see Rogers' Report on the Geology of Pennsylvania, Vol. II, p. 902, ) was shown in illustration. The gradual subterranean move- ments inward under a mountain chain, as the upper portions were removed and the remainder elevated, would carry the strata along on a support of diminishing width until they were folded upward and backward. The gradual increase towards the east in the amount of corrugation and steepness of dips, together with the supposed reversed folding by which the rocks of the eastern part of the Appalachian region seem to 32 PHILOSOPHICAL SOCIETY OF WASHINGTON. dip under older rocks, still further east appear, therefore, to favor the notion that the paleozoic rocks of the Appalachian region and the eastern part of the Mississippi basin were derived from the erosion of highlands formerly existing east of the Appalachian chain, now, perhaps, submerged in the Atlantic ocean. The downthrow of a fault, if formed in the manner supposed in the region under con- sideration, would accordingly be on its western side, as suggested above. The third communication was by Mr. S. F. Emmons on ^ ORE DEPOSITION BY REPLACEMENT. [Abstract.] After a few introductory remarks upon the relatively unsatis- factory condition of that branch of geology which treats of ore de- posits, considering the early date at which it was taken up, the speaker briefly reviews the existing theories and classifications, and shows that they are mainly based on the idea that each ore deposit is the filling of some pre-existing cavity or opening in the rock in which it is now found ; that so-called fissure veins, for instance, were once actually open cracks, and that irregular deposits in limestone have been made by the filling up of open caves, such as so fre- quently occur in these rocks. The result of his studies of the so- called " carbonate deposits " of Leadville, Colorado, has been to show that they are not the filling up of pre-existing cavities ; the caves there have been formed since the ore was deposited, as is proved by their crossing indiscriminately ore bodies and limestone. They belong to a class of deposits for which he proposes the name metamorphie deposits, or those which have been formed by a meta- somatic interchange between the vein and original rock material. In Leadville the principal deposits are an actual replacement of the limestone itself at or near the contact of this stratum with an overlying sheet of porphyry. This replacement action has in places proceeded so far that the entire stratum of ore-bearing limestone or dolomite, originally 150 to 200 feet thick, has been changed into vein material, which consists of silica and metallic minerals. This vein material was brought in solution by percolating waters, which had taken it up during their circulation through the adjoining and generally overlying eruptive rocks. A more detailed description of the phenomena of these deposits will be found in his paper en- GENERAL MEETING. 33 titled " Abstract of a Report on the Geology of Leadville," in the Second Annual Report of the Director of the United States Geo- logical Survey. While the speaker's studies have thus far been mainly confined to limestone deposits, he has reason to believe that essentially the same process has produced a large proportion of ore deposits in crystal- line and eruptive rocks, and that to the class of metamorphic de- posits belong most of the so-called fissure veins of the Rocky Moun- tain region. That is, that they are not the filling in of pre-existent open fissures by vein materials foreign to the adjoining rocks, but simply a metamorphic change of these rocks themselves along channels of easy access to percolating waters ; and according to the character of the material held in solution by these waters, these rocks have been more or less changed into quartz and metallic min- erals, to a greater or less width, as the case may be. Numerous instances of such veins will be found in the forthcoming Census Report upon the Statistics and Technology of the Precious Metals, by Mr. G. F. Becker and the speaker. 234th Meeting. April 21, 1883. Vice-President Billings in the Chair. Forty members present. The Chair announced that Messrs. Washington Carruthers Kerr and Samuel Franklin Emmons had been elected members. Mr. W. H. Dall addressed the Society on GLACIATION IN ALASKA, illustrating his remarks by maps of the territory and of the glacial areas of the St. Elias Alps and Kachekmak Bay, Cook's Inlet, the latter being from surveys made by him under the direction of the U. S. Coast Survey. He called attention in the first place to the wide differences in the character of the masses of ice resulting from the consolidation of snow by gravity (which would usually be classed as glaciers), as observed by him during nine years' exploration in Alaska. These might be classed under several heads : as plateau-ice, filling 34 PHILOSOPHICAL SOCIETY OP WASHINGTON. large areas of depression and without motion as a whole, but when sufficiently accumulated overflowing the edges of its basin in various directions ; as valley-ice, filling wide valleys of gentle incline both as to their axes and their lateral slopes, producing masses of ice moving in a definite direction but without lateral and sometimes even without terminal moraines ; as ice-cascades, formed in sharp nar- row ravines of very steep inclination, usually without well-defined surface moraines ; as typical glaciers, showing neve and lateral and terminal moraines ; and lastly, as effete or fossil glaciers, whose sources have become exhausted, whose motion has therefore ceased, and whose lower portions have become smothered by the accumu- lation of non-conducting debris. The very existence of one of these last has remained unknown for half a century, though the plateau underwhich it is buried has been described and mapped by explorers. Another form under which ice appears in Alaska is that of solid motionless layers, sometimes of great thickness, interstratified with sand, clay, etc. A deposit probably of this character is described by Nordenskiold, on the Asiatic coast, near Bering Strait. In Alaska this formation, in which ice plays the part of a stratified rock, extends from Kotzebue sound, where the greatest known thickness of the ice-layer, about three hundred feet, has been noted, around the Arctic coast, probably to the eastern boundary. In Kotzebue Sound the ice is surmounted by about forty feet of clay containing the remains of fossil horses, buffaloes (Bos latifrons, etc.), mountain sheep, and other mammals. Farther north the ice is covered with a much thinner coat of mineral matter or soil, usually not exceeding two or three feet in thickness, and rarely rises more than twelve or fifteen feet above high water mark on the sea coast. Its continuity is broken between Kotzebue Sound and Icy Cape by rocky hills composed chiefly of carboniferous limestones, which bear no glaciers and do not seem to have been glaciated. The absence of bowlders and erratics over all this area has been noted by Franklin, Beechey, and all others who have explored it. The remarkable extent and character of the formation was unknown previous to the speaker's investigations, though the ice cliffs of Kotzebue Sound had attracted attention from the time of their first discovery. Mr. Dall desired especially to emphasize the distinction between these strata of pure ice and the "frozen soil" so often alluded to by arctic explorers. The absence of frozen soil in the alluvium GENERAL MEETING. 35 of the Yukon Valley, far north of Kotzebue Sound, was noted, as well as the fact that this valley has, for some unexplained reason, a mean temperature considerably above the normal, so that its forests extend well beyond the Arctic circle. The distribution of glaciers, properly so-called, in Alaska, as far as our present knowledge goes, is confined to the region of the Alaskan range and the ranges parallel with it south of the Yukon Valley, but particularly to the coast mountains bordering on the Gulf of Alaska and the Alexander Archipelago, of which the Saint Elias Alps form the most conspicuous uplift. The distribution of stratified ice is all north of the Yukon Val- ley, which divides the two regions. Hence, for the glacial epoch, it may be presumed that the one is the equivalent of the other, and the fact that Arctic Alaska is marked by stratified ice, rather than glaciers such as those of Greenland, must be due to local geological and climatic peculiarities existing at the time. On the Asiatic coast, especially at Holy Cross Bay, in nearly the same latitude and with not very different topographic conditions, glaciers are abun- dant at the present time. On the mainland, facing the Alexander Archipelago, especially toward Lynn Canal, Icy Strait and the Stikine region, local glaciers are abundant, and traces of others, now dissolved, may be found on the lowlands of most of the islands. That these were always local, though doubtless very extensive, and that they were the pro- geny of the topography instead of being its parent, is obvious to anyone who has seen the coasts of Maine or Norway, which have been submitted to general glaciation, and will compare their rounded, worn, and moutonnee aspect with that of the sharp cliffs, beetling crags, narrow valleys, and scanty lowlands of the Alaskan islands. The speaker concluded, from his observations, that the extent of the Alaskan glaciers is greatly diminished from its former state, and is probably still diminishing; that the southern portion of the Territory is probably nearly or quite stationary, while the northern part is undergoing elevation ; and that, from the nature of the case, the area of stratified ice cannot be expected to increase or di- minish materially without changes in geological or climatic con- ditions too great to be anticipated. Mr. Alvord remarked that on Point Barrow frozen ground had been penetrated to a depth of thirteen feet. 36 PHILOSOPHICAL SOCIETY OF WASHINGTON. In reply to a question by Mr. Antisell, Mr. Dall said that little was known of the humidity of the interior of Alaska ; 23 inches of precipitation, nearly all in snow, had been observed in a single year at one point and 12 inches at another. Mr. F. B. Hough then read a paper on THE CULTIVATION OF THE EUCALYPTUS ON THE ROMAN CAMPAGNA, which was discussed by Messrs. E. B. Elliott and H. Farquhar. It is published in the American Journal of Forestry for June, 1883. 235th Meeting. May 5, 1883. Vice-President Billings in the Chair. Twenty-seven members and visitors present. The Chair announced the election to membership of Messrs. William Thomas Sampson, John Oscar Skinner, and Thomas Ceowder Chamberlin. The first communication was by Mr. H. A. Hazen on HYGROMETRIC OBSERVATIONS. [Abstract. ] After describing the various devices by which the moisture of • the air has been measured, and especially the novel and valuable apparatus of Crova, the speaker illustrated the difficulty of the subject by contrasting synchronous determinations made at four points within a radius of two miles, and then described some ex- periments tending to show the inaccuracy of the wet and dry bulb hygrometer, as ordinarily observed. The value of the wet bulb reading is enhanced by blowing on the bulb with a bellows, or otherwise subjecting it to a brisk current of air. Mr. Harkness remarked first, that Mr. Hazen's experiments appeared to prove the insufficiency of Regnault's formula, for they showed the difference between the indications of the wet bulb and dry bulb to be a function not only of the humidity, but of the velocity of wind ; second, that height of station above the ground GENERAL MEETING. 37 was a condition to which too little attention had been given ; and third, that there seemed a possibility of obtaining a slightly erro- neous vapor tension with Crova's apparatus. Mr. E. J. Farquhar then read a paper on DREAMS IN THEIR RELATION WITH PSYCHOLOGY. [Abstract.] Several theories of dreams were considered and none found en- tirely sufficient ; not because a new and complete one was to be proposed, but because all seemed a little too partial and limiting in their scope. After touching on the relation of dreams to sleep and to waking, as intermediate between them, discrediting many recorded experiments on the ground of their being vitiated by a special pur- pose latent in the mind, and pointing out that the usual supposition of our being often waked by the intensity of a dream appears to put cause for effect, since it must be the fact of waking that effects the dream, perhaps by slow degrees—the character of mental opera- tions in dreams was discussed. Dissent was expressed from the opinion that the dreaming state is devoid of such originating power as belongs to the waking ; this position was maintained by showing first, the extreme vividness and lastingness of impression often per- taining to dreams, apart from any features of horror; then the coherence, far from being unknown among them, yet of a peculiar kind ; and, finally, the true significance occasionally appearing in them, generally by figurative shape, amounting sometimes to a real enlightenment of the mind. Regarding the faculties or aspects of mind most apt to display themselves in dreams, it was held that all were liable to the exercise in turn, though some of the higher ones, especially the moral sense and judgment, less than others ; since these expressed a rarer and more distinctive force evolved and laid up by and for our relations with actual life, while other powers whose exercise is less of an expenditure from the most important vitalities of mind were freer at the time—the principles of conservation and struggle for existence being thought to apply among the mental elements. Thus, to a certain degree, the mind may be seen more clearly in its true character by means of dreams than awake, though in very partial views at a time. Unconscious mental action was reviewed in this connection, and it was held that not only the lower processes, called reflex, but many of the highest functions 38 PHILOSOPHICAL SOCIETY OF WASHINGTON. largely partake of this attribute. A great number of other points in regard to dreams were merely named as illustrating the fertility of the subject. 236th Meeting. May 19, 1883. Vice-President Hilgard in the Chair. Forty members and visitors present. It was announced from the General Committee that the following rules had been adopted : I. If the author of any paper read before a section of the Society desires its publication, either in full or by abstract, it shall be re- ferred to a committee, to be appointed as the section may determine. The report of this committee shall be forwarded to the Publica- tion Committee by the secretary of the section, together with any action of the section taken thereon. II. Any paper read before a section may be repeated, either en- tire or by abstract, before a general meeting of the Society, if such repetition is recommended by the General Committee of the So- ciety. Mr. Robert Fletcher made a communication entitled RECENT EXPERIMENTS ON SERPENT VENOM. It is published in the American Journal of the Medical Sciences for July, 1883. Mr. H. Farquhar then made a communication on FURTHER EXPERIMENTS IN BINARY ARITHMETIC, showing that the relation between the vertical and horizontal di- mensions of the characters used in the biuary notation is a factor in determining its economic value. He presented, also, the results of a series of comparative tests showing that the binary notation enables some persons, after brief practice, to perform addition more rapidly than with denary notation, while with others it requires a longer time. The latter class includes practiced computers, gene- rally, and the former those less accustomed to the use of figures. GENERAL MEETING. 39 Mr. Doolittle remarked that the most instructive results would be obtained by experimenting with young persons; and the subject was further discussed by Messrs. W. B. Taylor, E. B. Elliott, and C. A. Schott. 237th Meeting. June 2, 1883. Vice-President Hilgard, and afterward Mr. Harkness, in the Chair. Twenty-two members present. It was announced that the next meeting would be held October 13th. Mr. "W. Lee made a communication, with illustrations, entitled SKETCHES FROM MEDALLIC MEDICAL HISTORY. [Abstract.] The paper was prefaced by remarks on the value of coin and medal collecting as a profitable means of instruction, and by a recog- nition of the danger to which collectors are exposed of develop- ing a mania for collecting odd and curious things which cease to be instructive. An extended interest in numismatics commenced to show itself in this country in 1858, at which time there were probably not as many as one hundred coin collectors in the United States. The interest has grown rapidly, however, until now there must be on the books of the United States Mint the names of at least one thousand collectors who receive yearly the issue of the mint, with a special proof polish. In New York alone, during the year 1882, there were thirty-nine collections sold at public auction, the amount realized being '$68,441.36. The largest of these was the Bushnell collection, which realized $13,900.47. Sev- eral of our large cities have numismatic societies, some of which are designated as numismatic and archaeological societies ; and a number of periodicals devoted simply to the interest of numis- matics obtain a satisfactory circulation. The modes of striking off coins and medals were given somewhat in detail, and attention was then called to the important part which medals struck in honor of medical men and to commemorate im- 40 PHILOSOPHICAL SOCIETY OF WASHINGTON. portant events bearing directly upon the history of medicine have played throughout the history of the world. The illustrations of the paper included a hundred and fifty examples of the medals themselves, in regular sequence, from the days of Roman and Greek medicine down almost to the date of the paper itself, an interesting commemoration of events and individuals marking epochs in the history of medicine. These medals were taken up seriatim, references were made to the lives of individuals and the scientific work done by them, and descriptions were given of the occasions which called for the striking of medals. The paper closed with an expression of hope that the Society might be stimulated at the sight of so many handsome and perma- nent memorials of the men and times of the past, to attempt to preserve the features of its first president, Joseph Henry, in a similar enduring form. The bibliography of the subject was discussed at some length, and the following works were referred to : Mead, Richardi.—Dissertatio de Nummis quibusdam a Smyrnaeis in medicorum honorem percussis. Naples, 1752. Rudolphi, C. A.—Index numismatum in virorum de rebus medi- cis vel physicis meritorum memoriam percussorum. Berlin, 1st edition 1823, 2d edition 1825, 12mo., XII, 131 pp, 3d edition 1828, 4th edition 1829. (This work (2d edition) comprises the description of 523 medals struck in honor of 350 scientific and medical men.) Renauldin, Leop. Jos.—Etudes historiques et critiques sur les Medicins Numismatistes, contenant leur biographie et l'an- alyse de leurs ecrits. Paris, 1851, 8°, XVI, 574 pp. (This work contains the names of 61 physicians). Chereau (A).—Les mereaux et les getons de l'ancienne faculte de medecine de Paris. L'Union Medicale. Paris, 1873, 3 Series, XV, pp. 309, 321. Pfeiffer, (L) und Ruland (C).—Pestilentia in Nummis. Ges- chichte der grossen Volkskrankheiten in numismatischen Documenten. Ein beitrag zur Geschichte der Medicin und der Cultur. Tubingen, 1882, 8° X, 189 pp. Mit zwei Tafeln Abbildungen in lichtdruck. Wroth, Warwick.—Asklepios and the C«ins of Pergamon. From the Numismatic Chronicle and Journal of the Numismatic Society. London, 1882, Part I, Third Series, No. 5, pages 1 to 51, plates 3. Moehsen, J. C. G.—The exact title of this author's work is not known to the writer of the paper ; it was written in German, GENERAL MEETING. 41 and embodies a description of a collection of medals in Berlin struck in honor of physicians, giving 200 medals struck after the 15th century. Grotefend, C. L.—Die Stempel der Romischen Augenarzte. Hannover, 1867. Mr. T. N. Gill then made a communication on ANALOGUES IN ZOO-GEOGRAPHY. 238th Meeting. October 13, 1883. The Society, in accordance with the notice of adjournment at the June meeting, resumed its sessions. The President in the Chair. Forty-four members and visitors present. It was announced that during the vacation the Society had lost by death Surgeon General C. H. Crane, one of its Vice-Presidents ; Admiral B. F. Sands, one of its founders ; and Dr. Josiah Curtis. It was further announced from the General Committee that Mr. Garrick Mallery had been appointed Vice-President to fill the vacancy occasioned by the death of Mr. Crane, and that Mr. C. V. Riley had been added to the General Committee to complete its number. Mr. William B. Taylor read a paper entitled NOTE ON THE RINGS OF SATURN. [Abstract.] After an historic sketch of the varying and apparently incon- gruous observations by astronomers on the markings and aspects of the Saturnian rings, down to those of Schiaparelli of the Milan Observatory, (published in June last,) Mr. Taylor remarked that since the mathematical discussion by Prof. J. Clerk Maxwell, in 1857,* both the rigid and the fluid ring theories have been aban- doned ; and the discrete or meteoric constitution of the rings is now accepted by all physical astronomers as conclusively established. * On the Stability of the Motion of Saturn's Rings. 4:0. 71 pp. and I plate. Cambridge, Eng., 1859. 7 I 42 PHILOSOPHICAL SOCIETY OF WASHINGTON. Reference was then made to the startling announcement by Otto Struve, in 1851, that a careful comparison of the earlier with the later measurements showed that during the two hundred years of observation the rings had been widening, and the inner edge steadily approaching the body of the planet.* Considering the necessarily vast antiquity of the Saturnian system, such a change during the brief iuterval of human existence seems a priori almost infinitely improbable. The hypothesis of some that a meteoric ring has been drawn in by Saturn's attraction, within comparatively recent ages, seems entirely negatived by the circular symmetry of the system. It is not surprising, therefore, that Struve's inference has been re- ceived with an almost universal incredulity by the astronomical world. Robert Main, of the Greenwich Observatory, from a dis- cussion of his own measurements taken in the winter of 1852-'3, and in 1854, disputed the accuracy of Struve's measures ; and con- cluded that " no change has taken place in the system since the time of Huyghens."f And Prof. F. Kaiser, in a paper on " The Hypothesis of Otto Struve respecting the gradual increase of Saturn's Ring," etc., arrives at the same conclusion, and believes " there exists no reason whatever for supposing that the compound ring of Saturn is gradually increasing in breadth." | There seems to be little doubt of some unintentional exaggeration in Struve's tabulated results, which range from 4".6 : 6".5 for the ratio of ring breadth to space between ring and ball, in the time of Huyghens, 1657, to 7".4 : 3".7 for the ratio of breadth to space, by his own observation in 1851. Nevertheless it is a noteworthy fact that all the early drawings of Saturn made in the seventeenth cen- tury (many of which are figured by Huyghens in his Systema Sat- urnium, 1659) plainly exhibit the width of the ring as sensibly less than the dark space within ; while all modern observers would agree that the bright ring is now wider than the dark space, in about the ratio of 3 : 2 ; or were we to take the average of the esti- *Recueil des Memoires presentes [etc.] par les Astronomes de Poulkova. 4to. St. Petersburg, 1853. Vol. I, pp. 349-385. " Sur les Dimensions des Anneaux de Saturne." (Memoir read before Acad. Sci. ) A brief abstract of the memoir is given in the Monthly Notices, R. A. S., November 12, 1852. Vol. XIII, pp. 22-24. f Monthly Notices, R. A. S., December 14, 1855. Vol. XVI, pp. 30-36. \Mem. Acad. Sci., Amsterdam, 1858. A translation of the memoir is given in the Monthly Notices, R. A. S., January II, 1856. Vol. XVI, pp. 66-72. GENERAL MEETING. 43 mates of the last century, it would probably not vary far from 5".25:5".75; while the general average for the present century would probably be about 6".5 : 4".5. There seems, therefore, to be a real difference, not accounted for by inferiority of earlier instru- ments and estimates, nor by the existing uncertainties of modern measurements. The question will probably be definitely settled in less than a century. Meanwhile there is a need of some explana- tion of the apparently systematic and progressive divergence first pointed out by Struve; and we naturally ask, What indications are afforded by theory ? The elder Herschel, in 1789, (at the Saturnian equinox, when the edge of the ring was presented to view,) from supposed observation of protuberances moving on the line, believed that he had detected a rotation, whose period he estimated at lOh. 32m. 15s., for the outer edge of the ring.* The correctness of this interpretation was controverted by Schroeter, from observations at Lilienthal, on the next passage of Saturn's equatorial node in 1803 ; as it was after- ward questioned by Prof. G. P. Bond, of Harvard Observatory, from observations in 1848."}" It is scarcely doubtful that Herschel's period was derived from an entire misconception of the nature of the ring—which he firmly held to be solid—and that it possesses no scientific value whatever. A. Secchi, from certain recurrent irreg- ularities of phase observed at Rome in 1854, 1855, and 1856, in- ferred a rotation period of 14h. 23m. This is doubtless a nearer approximation (for the outer edge of the ring) than Herschel's es- timate. It is not probable, however, that the period of any portion of the ring will be determined by observation. Accepting the meteoric theory of the rings as now established, we may by Kepler's law compute with confidence the period of rotation of any part of the ring ; and we thus find — From the period of the inner Satellite (Mimas) 22I1. 37jm. — The period of outer edge of ring 14.I1. 30 m. " dividing stripe - nh. 20 ra. " inner edge of bright ring 7h. 12 m. " inner edge of dusky ring 5I1. 45 m. Mean period of ring (supposed solid) about ioh. 50 m. The period of the planet Saturn is lOh. 14m. * Phil. Trans. Roy. Soc. 1790: Vol. LXXX, p. 479; and 1792: Vol. LXXXII, p. 6. f Gould's AstronomicalJournal. 1850. Vol. I, pp. 20, 21. 44 PHILOSOPHICAL SOCIETY OF WASHINGTON. Thus regarding each constituent element of the ring as having its own independent rotation, (a condition absolutely essential to the stability of the system,) we may consider that from the compli. cated and variable perturbations by the exterior satellites, no one particle can revolve in a circular orbit, and hence that in a space so crowded there must be a considerable amount of interference. The collisions at intersecting orbits may result in heat or in disin- tegration ; but in any event they must tend to a degradation of motion, and hence to a slightly shortened mean radius-vector and a shortened period. Theoretically then such an effect as that indicated by Struve would seem inevitable, whether as a matter of fact it has been sufficient in a couple of centuries to be detected or not. And this involves a modified conception as to the earlier condition of the Saturnian rings. To suppose a fine web of nebulous matter con- tinuously spun out from Saturn's equator, with an unchanging balance of centrifugal and centripetal forces during the long ages while the planet was slowly contracting to one-half its radius, is certainly no easy task or plausible theory. If, however, we are now beholding but a stage of transitional development of the ring, we shall have to imagine its primitive radius considerably larger, and its width as probably very much narrower—so narrow indeed as to have a planetary or satellitic status, revolving in a single definite period — possibly that of Mimas the nearest satellite. Such a ring would present a condition of comparatively great stability ; and it may have been that only the secular recurrence of rare and remarkable conjunctions commenced upon it the work of disturbance and disintegration. When Galileo, the first to see the strange appendages to Saturn, (though without being able to distinguish the ansae as parts of a ring,) observed, in 1612, that they had entirely disappeared, he wrote in some dismay, " Has Saturn possibly devoured his own children ? " * So may perhaps the future astronomer, seeing but an airy trace of the historic ring, repeat the saying, Saturn has indeed devoured his offspring; not indeed completely, for a part will probably still remain ; nor with violent catastrophe, for the scattered fragments falling by their eccentricity will be absorbed as gently as are the meteors daily falling on our earth. * Third letter to Marc Velser, December I, 1 612. Opere di Galileo. 4tOi 4 vols. Padua, 1744: Vol. II, p. 123. GENERAL MEETING. 45 A subsidiary point deserving of notice is the certainty that the inner portions of the bright ring (and still more those of the dusky ring) are revolving in periods three or four hours shorter than that of Saturn himself. When Professor Hall made his brilliant discov- ery of the satellites of Mars, and announced that the inner satellite (Phobos) was found to have the short period of 7h. 38m. (or less than one-third of that of Mars) the fact was at once proclaimed by some as incompatible with the " nebular hypothesis." Everybody knows that the rotation periods of the sun and planets do not con- form to the third law of Kepler. Our own moon has an actual velocity in its orbit more than double that of our terrestrial equator. And had the moon a little less than one-third its present distance, (that is, were its radius-vector less than 70,000 miles,) its angular velocity would exceed that of the earth, or its period would be less than 24 hours. Or, stated in another way, our earth, if expanded to the orbit of the moon, (under the most favorable disposition of form and of homogenous density,) would occupy considerably more than a year in completing its rotation. The supposed nebular diffi- culty is therefore just as pertinent to our own satellite as to those of Saturn or of Mars. The obvious solution is, that all the planets (without exception) have lost a very large amount of rotatory energy ; and this may be largely or chiefly ascribed to the retarding effects of internal friction resulting from solar tides. And, given time enough, the rotation of every planet should be finally reduced to the lunar condition of a precise accord of its diurnal and annual periods. On any hypothesis whatever, it is certain that the rotations of the planets are very much slower (notwithstanding too the acceleration due to contraction) than they originally were. This fact certainly offers no objection to the nebular hypothesis. Mr. Dutton questioned the validity of Enuis' hypothesis, that the rotation of a nebular mass could be initiated by purely internal movements. Other remarks were made by Mr. Frisby. Mr. S. M. Burnett then made a communication on THE CHARACTER OF THE FOCAL LINES IN ASTIGMATISM, showing that the two lines which limit the focal interval of Sturm have been erroneously assumed to be straight. There is only one 46 PHILOSOPHICAL SOCIETY OF WASHINGTON. special case of the triaxial ellipsoid in which they are straight. In all other cases they are curved. The full text of this paper may be found in the Archives of Ophthalmology, Vol. XII, Nos. 3 aud 4. Mr. H. A. Hazen followed with a communication on THERMOMETER EXPOSURE. [Abstract.] Without entering upon the question, Where in any locality shall the air temperature be observed, it is proposed to discuss the even more important question, What shall be the environment of a thermometer that it may give the true temperature. The practice has been very various : in England the Stevenson shelter is re- garded as a standard : this is a double-louvred frame, wholly of wood, 18 x 10 x 18 inches, and placed about 4 feet above grass. In Russia we find a large wooden outside shelter of single louvres open to the north, inside of which is placed a metallic screen, the whole being exposed 12 or 13 feet above grass. In any exposure we should seek, first, to allow the freest possible access of the outer air, and second, to screen the thermometer from direct sun heat, from precipitation, and from radiation, whether (a) from surrounding objects by day or (b) to the sky at night. It is important that we adopt some ready means of accurately determining the air temperature which may answer as a standard of comparison. This we have in the swung thermometer, which, by its free motion through a large body of air shaded from direct sunlight in the daytime, is calculated to give good results. Experiments have been tried with a so-called "Pattern" shelter constructed of wood, of single louvres, inclined 30° to the hor- izontal, thus giving a good air circulation. The size is 4 x 3 x 3 feet, and it is erected at a height of 13 feet above a tin roof. In order to determine the least admissible size for a shelter, thermom- eters were placed in the Pattern 5 inches apart and running in an east and west direction, and these were observed morning and after- noon. It has been found that with a hot sun and still air the heat from the louvres rapidly diminishes with distance and becomes in- sensible at 15 inches. Comparisons have also been made for several weeks between the Russian and Pattern shelters ; and the means of 100 sets of continuous observations on a still day, and again on a windy day, are shown n the following table: GENERAL MEETING. 47 Dry ther- Wet ther- Relative humidity; mometer. mometer. per cent. Russian. Pattern. R. P. R.. P Still air 74°.8 73°.5 64°.o 62°.7 52.4 51. 1 Light south wind.. 77 .2 77 .1 62 .0 61 .0 36.7 34.1 These results show directly the advantage of a good circulation of air, and that after shielding from the sun and radiation to the sky with a shelter at least 3 feet long, we may neglect other consid- erations. Experiments are still in progress to determine the proper height above sod or roof, the proper exposure for a north window, and so forth. Mr. Antisell, referring to the general theme rather than to the special subject of the paper, took occasion to note that the practice of conducting meteorologic observations on the tops of high4iouses, while it may well subserve the special purposes of the Signal Service, renders their work of materially less value to the medical profession. There is so much change, especially of the moisture element, in the first few feet from the ground upward that no observations can be depended upon as reporting the conditions of the phenomena of disease unless they are made in the layer actually occupied by man. Mr. Taylor asked whether there might not be an error arising from the set given to the glass of the bulb by the pressure of the mercury of a whirled thermometer. Mr. Hazen replied that he had tested the effect of pressure ap- plied to the bulb with the finger, and found that the set produced was of very brief duration. He had also tested the thermic effect of the friction on the atmosphere incurred by rapid whirling, and found it inappreciable with a velocity of about fourteen miles an hour. On whirling a black bulb thermometer, he observed a change of several tenths of a degree, which appeared clearly referable to the greater coefficient of friction of the surface roughened by lamp- black. Mr. Graham Bell remarked that if we eliminate radiation and learn the absolute temperature of the air at the point of observa- tion, our knowledge is still limited to that point only, whereas for meteorologic purposes it is important to ascertain the average tem- perature of a body of air. He suggested the possibility of utilizing for this purpose a measurement of the velocity of sound, which 48 PHILOSOPHICAL SOCIETY OF WASHINGTON. velocity is dependent on atmospheric temperature and independent of barometric pressure. Mr. Dutton thought that the extreme delicacy of this observa- tion would involve an uncertainty greater than the one which now inheres in the determination. 239th Meeting. October 27, 1883. The President in the Chair. Forty-seven members and guests present. The Chair announced the death of two members since the last meeting — Leonard Dunnell Gale and Elisha Foote. Announcement was also made of the election to membership of Charles Doolittle Walcott. Mr. T. N. Gill made a communication on ICHTHYOLOGICAL RESULTS OF THE VOYAGE OF THE ALBATROSS. Mr. Alexander Graham Bell made the following communi- cation on FALLACIES CONCERNING THE DEAF, AND THE INFLUENCE OF SUCH FALLACIES IN PREVENTING THE AMELIORATION OF THEIR CONDITION. It is difficult to form an adequate conception of the prevalence of deafness in the community. There is hardly a man in the country who has not in his circle of friends and acquaintances at least one deaf person with whom he finds it difficult to converse excepting by means of a hearing-tube or trumpet. Now is it not an extraordinary fact that these deaf friends are nearly all adults? Where are the little children who are similarly afflicted? Have any of us seen a child with a hearing-tube or trumpet ? If not, why not? The fact is that very young children who are hard of hearing, or who cannot hear at all, do not naturally speak, and this fact has given origin to the term " deaf-mute," by which it is cus- tomary to designate a person who is deaf from childhood. "But are there no deaf children," you may ask, "excepting those whom we term deaf-mutes ? " No ; none.. In the tenth census GENERAL MEETING. 49 of the United States (1880) persons who became deaf under the age of sixteen years were returned as " deaf and dumb." Such facts as these give support to the fallacy that deafness, unaccom- panied by any other natural defect, is confined to adult life, and is specially characteristic of advancing old age. So constant is the association of defective speech with defective hearing in childhood that if one of your children whom you have left at home, hearing perfectly and talking perfectly, should, from some accident, lose his hearing, he would also naturally lose his speech. Why is this, and why are those who are born deaf always also dumb ? Fallacies Concerning the Dumbness of Deaf Children. The most ingenious and fallacious arguments have been advanced in explanation. George Sibscota,* in 1670, claimed that the nerves of the tongue and larynx were connected with the nerves of the ear, " and from this Communion of the vessels proceeds the sympathy between the Ear, the Tongue and Larynx, and the very affection of those parts are easily communicated one with the other. Hence it is that the pulling of the Membrane of the Ear causeth a dry Cough in the party ; and that is the reason most deaf men * * * are Dumb, or else speak with great difficulty ; that is, are not capable of framing true words or of articulate pronunciation by reason, of the want of that convenient influx of the animal spirits ; and for this cause also, it is that those who are thick of Hearing have a kind of hoarce speech." The value of Sibscota's reasoning may be judged of by the further information he gives us concerning the uses of the Eusta- chian tube. " By this it is," he says, " that Smoakers, puffing up their Bheeks, having taken in the fume of Tobacco, send it out at their Ears. Therefore the opinion of Alcmaeon is not ridiculous, who held that she-Goats did breathe thorough their Ears," &c, &c. It is easy for us to laugh at the fallacies of the past, but are we ourselves any less liable to error on that account? The majority of people at the present day believe that those who are born deaf are also dumb because of defective vocal organs. Now let us examine * I have been informed that Sibscota's work, " The Deaf and Dumb Man's Discourse," from which the above extracts are taken, is in reality a translation of another work by Anthony Densing, published in 1656. 50 PHILOSOPHICAL SOCIETY OF WASHINGTON. this proposition. It is a more ridiculous and absurd fallacy than that of Sibscota and more easily disposed of. The hypothesis that congenitally deaf children do not naturally speak because their vocal organs are defective involves the assump- tion that were their vocal organs perfect such children would natu- rally speak. But why should they speak a language they have never heard ? Do we speak any language that we have not heard? Are our vocal organs defective because we do not talk Chinese? It is a fallacy. The deaf have as perfect vocal organs as our own, and do not naturally speak because they do not hear. I have my- self examined the vocal organs of more than 400 deaf-mutes with- out discovering any other peculiarities than those to be found among hearing and speaking children. The deaf children of Italy and Germany are almost universally taught to speak, and why should we not teach ours? Wherever determined efforts have been made in this country success has followed and articulation schools have been established. Fallacy Concerning the Intelligence of Deaf Children. The use of the word " mute" engenders another fallacy concerning the mental condition of deaf children. There are two classes of persons who do not naturally speak—those who are dumb on account of defective hearing and those who are dumb on account of defec- tive minds. All idiots are dumb. Deaf children are gathered into institutions and schools that have been established for their benefit away from the general obser- vation of the public, and even in adult life they hold themselves aloof from hearing people ; while idiots and feeble-minded persons are not so generally withdrawn from their families. Hence the greater number of " mutes " who are accessible to public observation are dumb on account of defective minds, and not of defective hear- ing. No wonder, therefore, that the two classes are often con- founded together. It is the hard task of every principal of an institution for the deaf and dumb to turn idiots and feeble-minded children away from his school—children who hear perfectly, but cannot speak. Although it is evidently fallacious to argue that, because all deaf infants are dumb, and all idiots are dumb ; there- fore all deaf infants are idiots: still this kind of reasoning is un- consciously indulged in by a large proportion of our population ; and the majority of those who for the first time visit an institution GENERAL MEETING. 51 for the deaf and dumb express unfeigned astonishment at the bright- ness and intelligence displayed by the pupils. Why Hearing Children who become Deaf also become Dumb. I have stated above that children who are born deaf do not natu- rally speak because they cannot hear. For the same reason chil- dren who lose their hearing after having learned to speak naturally tend to lose their speech. They acquired speech through the ear by imitating the utterances of their friends and relatives, and when they become deaf they gradually forget the true pronunciation of the words they know, and have naturally no means of learning the pronunciation of new words ; hence their speech tends to become more and more defective until they finally cease to use spoken words at all. Adults who become deaf do not usually have defective speech, for in their case the habit of speaking has been so fully formed that the mere practice of the vocal organs in talking to friends prevents loss of distinctness. We can learn, however, from the case of Alexander Selkirk how important is constant practice of the vocal organs. This man, after about one year's solitary resi- dence upon an island, was found to have nearly forgotten his mother tongue; and we find that deaf adults who shrink from society and use their vocal organs only on rare occasions acquire peculiarities of utterance that are characteristic of persons in their condition, although the general intelligibility of their speech is not affected. Fallacies Regarding the Nature of Speech. The fallacies I have already alluded to respecting the difference between those who become deaf in' childhood and those who become deaf in adult life have their origin in a fallacy concerning the nature of speech itself. To most people, who do not reflect upon the sub- ject, it appears that speech is acquired by a natural process similar to that by which we acquire our teeth. At a certain age the teeth make their appearance, and at another age we begin to talk. To unreflecting minds it appears that we grow into speech; that speech is a natural product of the vocal organs, produced without instruc- tion and education ; and this leads directly to the fallacy that where speech is wanting or imperfect the vocal organs are defective. I have already stated that this cause has been assigned in expla- 52 PHILOSOPHICAL SOCIETY OF WASHINGTON. nation of the dumbness of children who are deaf. The idea gives rise also to the popular notion that stammering and other defects of speech are diseases to be " cured," and the attempt has been made to do so, even by heroic treatment. It is not so very long ago that slices have been cut from the tongue of a stammerer, in the vain hope of " curing " what was, after all, but a bad habit of speech. I have myself known of cases where the uvula has been excised to correct the same defect. The dumbness of the deaf and the defect- ive speech of the hearing are some of the penalties we pay for ac- quiring speech ignorantly, by mere imitation. If parents realized that stammering and other defects of speech were caused by igno- rance of the actions of the vocal organs, and not necessarily through any defect of the mouth, they would have their children taught the use of the vocal organs by articulation teachers, instead of patron- izing the widely-advertised specialty physicians, who pretend by secret means to " cure " what is not a disease. Speech is naturally acquired by imitation, and through the same agency defects of speech are propagated. A child copies the defective utterance of his father. A school-fellow mocks a stammering companion, and becomes himself similarly affected. In the one case the fallacy that the supposed disease is hereditary prevents attempts at instruction and correction, and in the other the idea that the affliction is the judgment of God in the way of punishment discourages the afflicted person and renders him utterly hopeless of any escape excepting by a miracle. A practical illustration of the fact that defective speech is prop- agated by imitation is shown in my own case. When I was a boy my father was a teacher of elocution, and had living with him at one time one or two pupils who stammered. While under the care of my father, these boys spoke clearly and well, without any ap- parent defect, but, owing to his being called away for a protracted period of time, his pupils relapsed, and the boys commenced to stammer as badly as at first. Upon my father's return he found a house full of stammerers. Sis own sons were stammering too ! I can well remember the process of instruction through which I went before the defect was corrected in my own case. Ignorance the Real Difficulty in the Way of Teaching Deaf Children to Speak. Speech is the mechanical result of certain adjustments of the GENERAL MEETING. 53 vocal organs, and if we can teach deaf children the correct adjust- ments of the perfect organs they possess, they will speak. The diffi- culty lies with us. We learn to speak by imitating the sounds we hear, in utter ignorance of the action of the organs that accompa- nies the sounds. I find myself addressing an audience composed of scientific men, including many of the most eminent persons in the country, and I wonder how many there are in this room who could give an intelligible account of the movements of their vocal organs in uttering the simplest sentence? We must study the mechanism of speech, and when we know what are the correct adjustments of the organs concerned, ingenuity and skill will find the means of teaching perfect articulation to the deaf. The Old Fallacy—" Without Speech, no Reason." I have already stated that children who are born deaf are also always dumb. How, then, can they think ? It is difficult for us to realize the possibility of a train of thought being carried on with- out words ; but what words can a deaf child know, who has never heard the sounds of speech ? When we think, we think in words, though we may not actually utter sounds. Let us eliminate from our consciousness the train of words, and what remains ? I do not venture to answer the ques- tion ; but it is this, and this alone, that belongs to the thoughts of a deaf child. It is hardly to be wondered at, therefore, that the fallacy should have arisen in the past that there could be no thought without speech ; and this fallacy prevented for hundreds of years any attempt at the education of the deaf. Before the end of the last century deaf-mutes were classed among the idiots and insane ; they had no civil rights, could hold no property ; they were irresponsible beings. Even those interested in the religious welfare of the world consigned their souls to the wrong place, for " faith comes by hearing," and how could a deaf child be saved ? I say that for hundreds of years the old fallacy, that " without speech there could be no reason," hindered and prevented any attempt at the amelioration of the con- dition of the deaf. But, strange to say, it was this very fallacy that first led to their education. It was attempted, by a miracle to teach them to speak. In Bede's History of the Anglo-Saxon church we read " How Bish- opp John cured a dumme man with blessing him." 54 PHILOSOPHICAL SOCIETY OF WASHINGTON. " And when one weeke of Lent was past, the next sounday he willed the poore man to come unto him ; when he was come, he bydd him put out his tounge and show it unto him, and taking him by the chiuue, made the signe of the holy crosse upon his tounge, and when he had so signed and blessed it, he commauuded him to plucke it in again, and speake saying, speake, me one word, say gea, gea, which in the english tounge is a worde of affirmation and consent in such signification as yea, yea.* Incontinent the stringes of his tounge were loosed, and he said that which was commanded him to say. The bishopp added certain letters by name, and bid him say A; he said A; say B, he said B, and when he had said and recited after the bishopp the whole cross rewe he put upon him sillables and hole wordes to be pronounced. Unto which when he answered in all pointes orderly, he commauuded him to speake long sentences, and so he did ; and ceased not all that day and night following, so louge as he could hold up his head from sleepe (as they make report that were present) to speake and declare his secret thoughtes and purposes, which before that day he could never utter to any mau."f Now, stripped of the miraculous, this is simply a case of articula- tion teaching. In the other countries of Europe the first attempts at the education of the deaf were also made by teaching them to speak, and as the early teachers were monks of the Roman Catholic Church, it is probable that these schools resulted from the attempts to perform the miracle of healing the dumb. A large proportion of the deaf and dumb who were thus brought together were success- fully taught to articulate. But now comes a marvel : It was found by the old monks that their pupils came to understand the utterances of others by watch- ing the mouth. Such a statement appears more marvelous to those who understand the mechanism of speech than to those who are ignorant of it ; and there is a general tendency to consider this ac- complishment as among the fictitious embellishments of the old nar- ratives. But the experience of modern teachers confirms the fact. John Bulwer, who is said to have been the earliest English writer upon the subject of the instruction of the deaf and dumb, published * It will be remembered that the original of this was in Latin, and that " the english tounge" here means what we now call the Anglo Saxon, f American Annals of the Deaf and Dumb, vol. I, p. 23 (1S48). GENERAL MEETING. 55 iii the year 1648 a treatise entitled "Philoeophus ; or, the Deaf and Durabe Man's Friend. Exhibiting the Philosophicall verity of that subtile Art, which may inable one with an observant Eie, to Ileare what any man speaks by the moving of his lips. Upon the same Ground, with the ad vantage, of au Historicall Exemplification, ap- parently proving, That a Man Borne Deafe and Dumbe may be taught to Ileare the sound of words with his Eie, and thence learn to speak with his tongue." Articulation Teaching in America. In Europe at the present time deaf children are much more com- monly taught to speak and understand speech than in this country. In the majority of our schools and institutions articulation and speech-reading are taught to only a favored few, and in these schools no use is made of articulation as a means of communication. A considerable number of the deaf children in our institutions could once hear and speak, and those pupils who retain some knowledge of spoken language have their vocal organs exercised for an hour or so a day in an articulation class under a special articulation teacher, but this is not enough exercise to retain the speech. I have seen a boy who became deaf at 12 years of age, and who had previ- ously attended one of our public schools, go into an institution for the deaf and dumb talking as readily as you or I and come out a deaf mute. Few, if any, attempts are made to teach articulation to those who have not naturally spoken, except at the special request of parents who desire that the experiment shall be tried with their children. I have seen a congenital deaf mute, who also had a sister deaf and dumb, who was taught to speak in adult life, and I found upon ex- periment that he could understand by ear the words and sentences that he had been taught to articulate when they were spoken in an ordinary tone of voice about a foot behind his head, yet this young man had been educated at one of our best institutions without ac- quiring articulation, and as a consequence he grew up a deaf mute and married a deaf mute. He informed me himself that he could hear the people talking in the workshop where he was employed, but did not understand what they said. As a matter of personal observation I am convinced that a large proportion of the congenitally deaf are only hard of hearing, and this belief is supported by the fact that it used to be the custom in 56 PHILOSOPHICAL SOCIETY OF WASHINGTON. some of our institutions to summon the pupils from the play-ground by the ringing of a bell! Does this not indicate that a large num- ber of the pupils could hear the ringing of the bell, and that they told the others who could not hear at all? Such pupils could have been taught to speak at home by their friends if artificial assistance had been given to their hearing. There was no necessity for their ever becoming deaf and dumb. It is only within the last fifteen years or thereabouts that schools have been established in the United States where all the deaf chil- dren admitted are taught articulation and speech-reading, but such schools are rapidly increasing in number. Still, it is not generally known that the experimental stage has passed, and that all deaf mutes can be taught intelligible speech. This is now done in Italy and Germany, and the international conventions of teachers of the deaf and dumb held recently at Milan and Brussels have decided in favor of articulation for the deaf. I have stated before that the difficulties in the way of teaching articulation are external to the deaf. They lie with us and in our general ignorance of the mechanism of speech. A teacher who does not himself understand the mechanism of speech is hardly competent to produce the best results. So dense is the general ignorance upon this subject that it is probable that of the 50,000,000 of people in this country the number of persons who are familiar with all that is known concerning the mechanism of speech might be numbered on the two hands. Considering this, the success obtained in our articulation schools is gratifying and wonderful. Upon the Art of Understanding Speech by the Eye. It has been found in the articulation schools of this country that deaf children can acquire the art of understanding by eye the utter- ances of their friends and relatives, and this fact has led some teachers to suppose that speech is as clearly visible to the eye as it is to the ear, and this fallacy tends to hinder the acquisition of the art by their pupils. When we examine the visibility of the elementary sounds of our language we find that the majority can not be clearly distinguished by the eye. How then, you may ask, can a deaf child who cannot distinguish the elements understand words which are combinations of these elements? When the lips are closed we cannot see what is going on inside GENERAL MEETING. 57 the mouth. The elementary sounds of our language, represented by the letters P, B, and M, involve a closure of the lips. Hence the differences of adjustment that originate the differences of sound are interior and cannot be seen. But while the deaf child may not be able to say definitely whether the sound you utter is P, B, or M, he knows certainly that it must be one of these three, for no other sounds involve a closure of the lips. And so with the other ele- ments of our language. While he may not be able to tell definitely the particular element to which you give utterance, he can gener- ally refer it to a group of sounds that present the same appearance to the eye. In the same manner he may not be able to tell the pre- cise word that you utter, but he can refer it to a group of words having the same appearance. For instance, the words " pat," " bat," and " mat " have the same appearance to the eye. While he can- not tell which of these words you mean when it is uttered singly, he readily distinguishes it in a sentence by the context. For in- stance, were you to say that you had wiped your feet upon a " mat," the word could not be " pat " and it could not be " bat." Here we come to the key to the art of understanding speech by the eye—Context. But this involves, as a prerequisite, a compe- tent knowledge of the English language ; and we may particularly distinguish those children who have acquired the art from those who have not, by their superior attainments in this respect. We can, therefore, see why children who have become deaf after hav- ing learned to speak, naturally acquire this power to a greater ex- tent than those who are born deaf. There are many cases of congenitally deaf children who have ac- quired this art as perfectly as those who have become deaf from disease; but in every case such children have been thoroughly familiar with the English language, at least in its written form. Fallacies Hegarding Speech-reading. The fallacy that speech is as clearly visible to the eye as it is audible to the ear hinders the acquisition of the art by causing the teacher to articulate slowly and word by word, even opening the mouth to its widest extent to make the actions of the organs more visible. When we realize that context is the key to speech-read- ing, theory asserts that ordinary conversational speech should be more intelligible than slow and labored articulation. This is amply proved by the experience of the most accomplished speech-readers. 58 PHILOSOPHICAL SOCIETY OF WASHINGTON. I have been told by one who has acquired this art that when intro- duced to strangers their speech is more readily understood if they are not aware they are speaking to one who cannot hear. The moment they are told they commence to speak slowly and open their mouths to an unnatural extent, thus rendering their articula- tion partially unintelligible. The change brought about by the knowledge that the listener could not hear was sometimes sudden and great. I have lately made an examination of the visibility of all the words in our language contained in a small pocket dictionary, and the result has assured me that there are glorious possibilities in the way of teaching speech-reading to the deaf, if teachers will give special attention to the subject. One of the results of my investigation has been that the ambigui- ties of speech are confined to the little words, chiefly to monosylla- bles. The longer words are nearly all clearly intelligible. The reason is obvious, for the greater number of elements there are in a word the less likelihood is there that another word can be found that presents exactly the same outline to the eye. We need never be afraid, therefore, of using long words to a deaf child, if they are within his comprehension. We are apt to have the idea that short words will be simpler, and we sometimes try to compose sentences consisting as much as possible of monosyllabic words, under the impression that such words are easy for the pupil to pronounce and read from the mouth. It is more common, there- fore, to present such sentences to beginners than to more advanced pupils. Now, I do not mean to say that these sentences may not be easier for a child to pronounce, but the words used are the most ambiguous to the eye. Such a simple word as " man," for instance, is homophenous with no less than thirteen other words. A few years ago I dictated a string of words to some pupils, with the object of testing whether they judged by context or were able to distinguish words clearly by the eye. The results are instruct- ive. Among the words dictated occurred the following : " Hit — rate— ferry— aren't—hat— four— that— reason— high— knit donned—co." I told the pupils not to mind whether they under- stood what I said or not, but simply to write down what they thought the words looked like, and what do you think they wrote? Upon examining their slates I found that nearly every child had written the following sentence : " It rained very hard, and for that reason GENERAL MEETING. 59 I did not go." I told the pupils to be very careful to observe whether they could distinguish any difference between the words I uttered and the words they wrote. I therefore went over the whole string of words again, articulating them one by one very distinctly. No difference whatever was detected. The mother of one of my pupils was present, and was greatly as- tonished to see her daughter writing down words so different from those I had pronounced. She said that she could not have believed that her daughter could have been so stupid ; but her surprise was increased when she found that the other children had written the same sentence. I told her that there was no difference in appear- ance between the words I had uttered and the words they had writ- ten. She desired to test the matter herself with her own child. She asked her daughter to repeat after her the words I had written, but the result was the same. The last part of the sentence she re- peated at least a dozen times, without shaking her daughter's con- fidence in the belief that the words she had uttered were precisely the same as those spoken by her mother. To one who could hear, it was a startling revelation to observe the confidence of the child in the accuracy of her replies. " Repeat after me," said the mother, as she pronounced the words singly and with deliberate distinctness : " high ;" answer, " I ; " knit," ans., " did ;" " donned," ans., " not ; " " co," ans., " go./ "Are you sure you have pronounced the words exactly as I have said them ?" Ans. " Yes ; perfectly certain." " Try again." " Knit," answer, "did;" "donned," answer "not." "Are you sure I said that?" Ans. " Yes ; absolutely sure." " Try again," and here the mother mouthed the word " donned," ans., " not." The mother was con- vinced, and she left the room with the remark that she felt that she had been very cruel to her child through ignorance of the fact that words that were very different to her ear looked alike to her child, and could not possibly be distinguished, excepting by context. I have seen a teacher attempting to impart instruction to a deaf child by word of mouth. She would speak word by word, and the pupil would repeat after her. Upon one occasiou the pupil gave utterance to a very different word from that which had been spoken by the teacher. The latter repeated the word a number of times, opening her mouth to the widest extent, and the boy each time re- peated the incorrect expression. The teacher grew annoyed at the supposed stupidity of the pupil, and the pupil grew sulky, and was 60 PHILOSOPHICAL SOCIETY OF WASHINGTON. discouraged in his attempt to read from the mouth ; whereas, in reality, it was not the stupidity of the boy that was in the way of his progress, but the ignorance of the teacher, who did not know that the words that were so different to her ear were absolutely alike to his eye. Some teachers, in their anxiety to teach speech-reading to their pupils, have the idea that they should refrain from every other mode of communication, so that their pupils may be forced to ob- serve the movements of the mouth, and the mouth alone. For in- stance, it is easy to write an ambiguous word or to spell it by a manual alphabet, but some teachers refrain from doing so, under the impression that this practice leads the pupil to depend upon the hand instead of the mouth. Again, deaf persons gather an idea of the emotion that actuates a speaker by the expression of his countenance. In fact facial expression is to the eye what the modulation of the voice is to the ear. It gives life to the inaudible utterances of the mouth ; but there are some teachers who are so afraid that their pupils may come to depend upon the face instead of the mouth, that they think they should assume an impassive countenance from which nothing could be inferred. Requisites to the Art of Speech-reading. If we examine the visibility of speech and the causes of its in- telligibility, we shall find that there are three qualifications that must be possessed by a deaf child in order that he may understand readily the utterances of his friends. Omit any one of these quali- fications and good speech-reading is an impossibility : I. The eye must be trained to recognize readily those movements of the vocal organs that are visible. Has this ever been done ? Have not pupils been required to grapple with all the difficulties of speech-reading at once, and to observe not only the movements of the vocal organs, but to find out the meaning of what is said ? II. I have already explained that certain words have the same appearance to the eye, and it is necessary, if the pupil is to under- stand general conversation, that he shall know the words that look alike, so that a given series of movements of the vocal organs shall suggest to his mind not a single word, but a group of words, from which selection is to be made by context. An illustration will explain what I mean. There are many GENERAL MEETING. 61 words which have the same sound to the ear, but different signifi- cations. For instance, were I to ask you to spell the word " rane," you could not tell whether I meant " rain," " rein," or " reign." These words sound alike, but they lead to no confusion, for they are readily distinguished by context. In the same way " homo- phenous words," or words that have the same appearance to the eye, are readily distinguished by context. As a general rule when a teacher finds that her pupil does not understand a given word, she supposes the non-comprehension to be due to an untrained eye, and this leads to the patient repetition of the word with widely opened mouth, to make the action of the organs more visible. This, unintentionally, enables the pupil to acquire a knowledge of homophenous words ; for, when he fails to understand in the first instance, he is requested to try again. He then guesses at the meaning. He thinks of all the words that past experience has taught him looked something like the word pro- posed, and after a series of guesses generally succeeds in his at- tempt to unravel the meaning. In this way success comes at last, not in consequence of the pupil seeing more than he saw at first, but in consequence of knowledge gained by experience of failure. He learns what words present the same appearance to the eye. Let teachers find out the words that look alike, and teach them in groups to their pupils. In this way instruction will take the place of painful experience. III. The third requisite to good speech-reading is familiarity with the English language. Familiarity with our language, either in its written or spoken form, is absolutely essential in order that a deaf person may make use of context in his attempt to decipher our speech. It is a mental problem that the deaf child has to solve and not solely a problem of vision. The eyes of the con- genially deaf, if there is any difference at all, are rather stronger and better than the eyes of those who become deaf from disease; and yet, as a class, the congenitally deaf acquire the art of speech- reading with much more difficulty than those who could speak be- fore they became deaf. The reason is, that, as a class, the former have not a vernacular knowledge of our language even in its writ- ten form, while the latter have. Children who become deaf in infancy from disease are at as great a disadvantage in this respect as the congenitally deaf, and for the same reason. I shall inquire more particularly into the cause of this lack of 62 PHILOSOPHICAL SOCIETY OF WASHINGTON. familiarity with the English language, and I snail show that it results from a wide-spread fallacy regarding the nature of language and the means by which our language should be taught. In the meantime I shall simply direct attention to the fact that those who are deaf from infancy do not, as a general rule, become familiar with the English language even in its written form. It is obvious that if we talk to deaf children by word of mouth, and refrain from explaining, by writing or some other clearly visi- ble means, the words that are ambiguous, those pupils who are already familiar with the language have very great advantages over the others. They have a fund of words from which to draw, they can guess at the ambiguous word and substitute other words within their knowledge so as finally to arrive at the correct mean- ing. But young children who have been deaf from infancy and who never, therefore, have known our language, are not qualified at once for this species of guess-work. They know no words ex- cepting those we teach them, and have, therefore, no fund to draw upon in case of perplexity. If we commence the education of such children by speech-reading alone they are plunged into dif- ficulties to which they have not the key. To such children it becomes a matter of absolute necessity that our language should be presented to them in an unambiguous form. With such pupils, writing should be the main reliance, and speech- reading can only be satisfactorily acquired by the constant accom- paniment of writing, or its equivalent—a manual alphabet. I have no hesitation in saying that the attempt to carry on the general education of young children who are deaf from infancy by means of articulation and speech-reading alone, without the habitual use of English in a more clearly visible form, would tend to retard their mental development. I do not mean to say that this is ever actu- ally done, but I know there is a tendency among teachers of articu- lation to rely too much upon the general intelligibility of their speech. Let them realize that the intelligibility is almost entirely due to context, and they will rely more upon writing and less upon the mouth in their instructions to young congenitally deaf children. After a probationary period, pupils who could speak before they became deaf become so expert in speech-reading that the regular instruction of the school-room can be carried on through its means without detriment to the pupil's progress. The exceptional cases of congenitally deaf persons who have become expert in this art GENERAL MEETING. 63 assures us that, with all who are deaf from infancy, we can cer- tainly achieve the same results if only we can give them a sufficient knowledge of our language, at least in its written form. In the early stages of the education of the congenitally deaf it appears to me that written English should be made the vernacular of the school-room, and that all words or sentences written should also be spoken by the teacher and read by the pupils from the mouth. When the English language has become vernacular there is no reason why instruction should not also be given by word of mouth alone (as in the case of those who could speak before they became deaf) without interfering with mental development. Before leaving this subject I would say that it is of importance to remember that speaking and understanding speech by the eye are two very different things. We can all of us speak very readily, but I fancy it would puzzle most of us to be called upon to tell what a speaker says by watching his mouth. The congenitally deaf can certainly be taught to speak intelligibly even by persons unfamiliar with the mechanism of articulation. Such pupils should therefore be taught to articulate, and their vocal organs should be continually exercised in the school-room by causing them to speak as well as to write. The congenitally deaf can be taught to articulate even be- fore they are familiar with English, but I do not think they can acquire the power of understanding ordinary conversational speech by watching the mouth, at least to any great extent, until after they have become familiar with our language. Gesture Language. I have already stated that the old fallacy, " without speech there can be no reason," prevented for hundreds of years any attempt at the education of the deaf and dumb, and now I come to the mem- orable experiment that forever exploded the fallacy. Towards the latter end of the last century the Abbe de l'Epee, during the course of his ministration in Paris, entered a room in which two girls were sewing. He addressed some remarks to them, but received no reply. These girls were deaf and dumb. At once the kind heart of the good Abbe was touched, and he determined to devote his life to the amelioration of the condition of the deaf and dumb. He gathered together quite a number of deaf children, who made their home with^him. He spent his time in their society and de- voted to their comfort all that he possessed, reducing himself even 64 PHILOSOPHICAL SOCIETY OF WASHINGTON. to poverty for their sake. He soon observed that these children were communicating with one another, but not by speech. They were inventing a language of their own, unlike any of the spoken languages of the earth—a language of gestures. These children were reasoning by means of this language ; they were thinking in gestures instead of in words, and the idea occurred to the Abbe de l'Epee that the old dogma that had for so many hundred years pre- vented the education of the deaf was a fallacy. Here was nature developing an instrument of reason with which speech had nothing to do. Why should he not study this gesture language and assist these children in their attempts to perfect a means of communica- tion of this kind, and why should he not use this means of com- munication so as to lead their minds to higher and ever higher thoughts? He did so and succeeded in developing the "sign lan- guage " that is now so extensively employed in this country in the education of the deaf. The experiment at once attracted at- tention. Kings and Emperors visited the humble abode of the Abbe de l'Epee and were astonished by what they saw. He con- versed with his pupils in the gesture language, and he taught them through its means the meaning of written French, so that they were enabled to communicate with hearing persons by writing. The Fallacy that a Gesture Language is the only Form of Language that is Natural to the Congenitally Deaf. The old fallacy was done away with, but a new one immediately took its place, which has been introduced into our country with the language of signs, and is now the main obstacle to the acquisition of English by the congenitally deaf. The fallacy to which I allude is that this gesture language is the only language that is natural to the congenitally deaf, and that therefore such children must acquire this language as their vernacular before learning the English lan- guage, and must be taught the meaning of the latter through its means. To my mind such a statement consists of a succession of fallacies, each one resting on the preceding. The proposition that the sign language is the only language that is natural to congeni- tally deaf children is like the proposition that the English language is the only language that is natural to hearing children. It is nat- ural only in the same sense that English is natural to an American child. It is the language of the people by whom he is surrounded. A congenitally deaf child who for the first time enters an insti- GENERAL MEETING. 65 tution for the deaf and dumb finds the pupils and teachers em- ploying a gesture language which he does not understand ; but in time he comes to understand it, and learns by imitation to use it, just as an American child in Germany comes in time to understand and speak German. Although congenitally deaf children, when they enter an institu- tion, do not understand or use the sign language as there employed, they each know and use a gesture language of some kind, which they employ at home in communicating with their friends and rela- tives. Hence it is argued that if the " sign language " employed in our institutions is not the only one, a gesture language of some kind is necessarily the vernacular of the congenitally deaf child. The scope of the statement is thus widened, and the proposition we have now to consider may be thus expressed : Gesture language, in the wider sense, is the only form of language that is natural to those who are congenitally deaf. It is a matter of great importance to the 34,000 deaf-mutes of this country, and to their friends and relatives, as well as to all persons who are interested in the amelioration of the condition of the deaf and dumb, that we examine this proposition with care and decide whether it is a fallacy or not. To my mind it is a fallacy based upon another concerning the nature of language itself, namely, that there is such a thing as a natural language. Such an idea has led to errors in the past, and will ever continue to do so. We have all read of the monarch of ancient times, who is recorded to have shut up a number of little children by themselves, and to have given orders to their attendants to hold no communication with them, so that he might observe what language they would naturally speak as they grew up. It is recorded that the first word uttered was a Greek word, from which it was argued that the Greek lan- guage was the natural language of mankind. In the seventeenth century the ingenious Van Helmont was im- bued with the idea that the Hebrew language was of divine origin, from which he argued that Hebrew was the natural language of mankind, and that the shapes of the Hebrew letters had some nat- ural relation to the sounds they represented ; that they pictured, in fact, the positions of the vocal organs in forming the sounds. The latter idea led him to employ the characters as a means of teaching articulation to a deaf-mute ; but the former idea led him to teach his deaf-mute Hebrew, instead of his native tongue. 66 PHILOSOPHICAL SOCIETY OF WASHINGTON. When we examine the languages of the world that are naturally acquired by hearing children, we fail to discover any natural con- nection between the sounds of the words and the things they repre- sent ; everything is arbitrary and conventional. Origin and Mode of Growth of a Gesture Language. Now, let us examine for a moment the nature of a gesture lan- guage and the manner in which it comes into existence. You are, we shall suppose, a farmer, and your little deaf boy comes run- ning into the house in great excitement, anxious to tell you some- thing he has observed. How does he do so? We shall imagine a case. He commences by placing his hands above his head, bowing low, and marching about the room, after which he points out of the window. You shake your head ; you have not the remotest idea what he means. His face assumes an anxious look, and down he goes upon his hands and knees, and scrambles over the floor, touching the carpet with his mouth from time to time, and then again points out of the window. Still you do not comprehend. A look of perplexity crosses his face. What can he do to make you understand ? At last his face lights up, as a new thought comes into his mind, and he touches the bridge of his nose and again points out of the window. But, alas ! alas ! you cannot understand. The little fellow is perplexed and troubled. At last, in despair, he takes hold of your coat and pulls you out of the door, around the corner, and you find your cow in the turnip patch. Now you begin to understand what it was he meant to say ; he had tried to picture the -cow, and to imitate its actions. The hands held above the head had indicated the horns ; the scrambling on the floor on his hands and knees had imitated the action of a four-footed animal, and his mouth to the carpet meant the cow eating the turnips. But how about the bridge of his nose ? You will probably observe that the cow to which he referred had some white spot or other mark upon the nose, and the gesture of the child had not indicated a cow in general, but your black cow " Bessie," with the white spot on her nose, in particular. GENERAL MEETING. 67 Having advanced thus far in the comprehension of his meaning, do you think that the child will take the trouble to go through this same pantomime the next time he wishes to tell you about your cow ? No. He may commence such a pantomime, but before he gets half through you understand what he means, and he never completes it. A process of abbreviation commences, until finally a touch on the bridge of his nose alone becomes the name of your black cow " Bessie," and the simple holding of his hands above his head conveys to your mind the idea of a cow in general. By a natural process of abbreviation the child arrives at a sim- ple gesture or sign for every object or thing in which he is inter- ested. But there are many thoughts he desires to express which are ab- stract in their nature. How, for instance, can he indicate by any sign the color of an object? Suppose, by way of illustration, that he desired to communicate to you the idea that he had seen in the road a cow that was perfectly white ? I shall try to depict the conversation between yourself and your deaf boy as it might actually have occurred. The boy. The boy points to the road, touches his teeth, and holds his hands above his head. You gather from this a vague idea of some connection between that road, the boy's teeth, and a cow. Here is a problem : What did he mean ? It is pretty clear that he had seen a cow in the road, but what connection had his teeth with that ? Perhaps the cow's teeth were peculiar. You think you had better get him to explain, so — The father. You touch your teeth with an interrogative and puzzled look. The boy. The boy responds by showing you his shirt sleeve and pointing to the road. Can he mean that there was any connection between his shirt sleeve and the cow. To clear this point — The father. You touch his shirt sleeve and raise your hands above your head with a look of interrogation. The boy. The boy nods vigorously, raises his hands above his head, and makes his sign for " snow," followed by other signs for objects that are white. After he has presented a sufficient number of such signs, you per- ceive that the one thing common to them all was their color—they 68 PHILOSOPHICAL SOCIETY OF WASHINGTON. were white. And thus you gain the idea that the cow was white. Do you suppose he goes through this process every time he desires to communicate the idea of white? No; he remembers the object which had conveyed to your mind the idea that that cow was white, and the sign for this object is ever after used as an adjective, quali- fying the object the whiteness of which he desires to indicate. Of course you cannot predicate what this particular sign may be. I have seen children who have conveyed the idea by touching their teeth ; others who expressed it by an undulatory downward move- ment of the hand, expressive of the way in which a snow-flake falls to the ground. It will thus be understood that a deaf child first commences to express his ideas by pantomime, and that by a process of abbrevia- tion pantomimic gestures come to be used in a conventional manner. Pantomime is no more entitled to the name of language than a picture is, although many ideas can be conveyed through its means. In proportion as it becomes more conventional and arbitrary it be- comes more and more worthy of the name of language. The Sign-Language of Our Institutions. Now, when the deaf children who lived with the Abbe de l'Epee were first brought together, each of them used a gesture-language he had invented for himself as a means of communicating with his friends at home. Thus there were as many gesture-languages as there were children. The only element common to these languages was probably the pantomime from which they had all sprung. But now what happened ? Association and the necessity of intercom- munication led to the adoption of common signs. Each child pre- sented his gestures to his fellows, and by a process of selection those signs that appeared to the majority to be most fitting survived, and were adopted by the whole ; and the synonymous signs, which were not so well fitted, were either forgotten by disuse or used in a new meaning to express other ideas. I do not wonder at the interest displayed in this growth by the Abbe de L'Epee and his contemporaries. To my mind it was the most interesting and instructive spectacle that has ever been pre- sented to the mind of man — the gradual evolution of an organized language from simple pantomime. When, in 1817, the first school for the deaf and dumb was opened in America, the sign-language as used in the school of the Abbe de GENERAL MEETING. *69 l'Epee (then under the charge of his successor, the Abbe Sicard) was imported from France, and became the medium of instruction. The teachers trained in this school naturally became the principals of other institutions established upon its model, and thus the sign- language has been diffused over the length and breadth of our land. I heartily agree with all that experienced teachers of the deaf have urged concerning the beauty and great interest of this gesture language. It is indeed interesting to observe how pantomimic ges- tures have been abbreviated to simple signs expressive of concrete ideas ; how these have been compounded or have changed their meaning to indicate abstract thoughts ; and how the sequence of the sign-words has to a certain extent become obligatory, thus forming a sort of gesture syntax or grammar. The original stock or stocks from which our languages are derived must have disappeared from earth ages before historic times ; but in the gesture speech of the deaf we have a language whose history can be traced ab origine, and it has appeared to me that this fact should give it a unique and independent value. In the year 1878, in a paper read before the Anthropological Society of London, I advocated the study of the gesture language by men of science ; for it seemed to me that the study of the mode in which the sign language has arisen from pantomime might throw a flood of light upon the origin and mode of growth of all languages. You may ask why it is that, with my high appreciation of this language as a language, I should advocate its entire abolition in our institutions for the deaf. I admit all that has been urged by experienced teachers con- cerning the ease with which a deaf child acquires this language, and its perfect adaptability for the purpose of developing his mind ; but after all it is not the language of the millions of people among whom his lot in life is cast. It is to them a foreign tongue, and the more he becomes habituated to its use the more he becomes a stranger in his own country. This is not denied by teachers of the deaf and dumb, but the argument is made, as I have stated above, that it is the only lan- guage that is natural to congenitally deaf children, or that at all events, some form of gesture language must necessarily be their vernacular, and be employed to teach our English tongue. 70 PHILOSOPHICAL SOCIETY OF WASHINGTON. The Fallacy that a Gesture Language is the only form of Language in which a Congenitally Deaf Child can Think. Now what do we mean by a language being " natural" or not? I cannot believe that in this 19th century any one really entertains the fallacy that there is a natural language per se. So I presume that that language is considered natural to a person in which he thinks. Under this meaning the proposition assumes this shape : The sign language taught in our institutions, or a gesture language of some kind, is the only form of language in which a congenitally deaf child can think ; that is, it is the only language of which the elements can be associated directly with the ideas they express. In this form the fallacy is easily exploded, for in the course of the last one hundred years so many experiments have been made in the education of the deaf that we now know with absolute cer- tainty that deaf children can be taught to associate written words directly with the ideas they represent ; and when they are taught to spell these words by a manual alphabet, the movements of the fingers become so natural a method of giving vent to their thoughts that even in sleep their fingers move when they dream. Not only has written English been made the vernacular of con- genitally deaf children, but the same result has been achieved with written French, German, Spanish, Dutch, and other languages. Congenitally deaf children who have been taught articulation move their mouths in their sleep and give utterance to words when they dream. Laura Bridgman, the blind deaf-mute, was taught by the late Dr. Howe to gather ideas through the sense of touch. English words printed in raised letters were presented to her sense of touch in connection with the objects which they represented, and she associated the impressions produced upon the ends of her fingers with the objects themselves. The English language in a tangible form became her vernacular. All these facts assure us that any form of language may become natural to a deaf child by usage, so long as it is presented to the senses he possesses. There is only one way that language is natu- rally acquired, and that is by usage and imitation. Any form of language that can be clearly appreciated by the senses the deaf child possesses, will become his vernacular if it is used by those about him. GENERAL MEETING. 71 Why the Deaf employ a Gesture Language. A gesture language is employed by a deaf child at home, not because it is the only language that is natural to one in his con- dition, but because his friends neglect to use iu his presence any other form of language that can be appreciated by his senses. Speech is addressed to his ear ; but his ear is dead, and the motions of the mouth cannot be fully interpreted without previous familiarity with the language. On account, therefore, of the neglect of parents and friends to present to his eye any clearly visible form of lan- guage, the deaf child is forced to invent such a means of communi- cation, which his friends then adopt by imitation. I venture to express the opinion that no gesture language would be developed at home by a deaf child If his parents and friends habitually em- ployed, in his presence, the English language in a clearly visible form. He would come to understand it by usage, and use it by imitation. An old writer, George Dalgarno, in 1680, expressed the opinion, in which I fully concur, that " there might be successful addresses made to a dumb child even in its cradle, risu cognoscere matrem, if the mother or nurse had but as nimble a hand as usually they have a tongue." When deaf children enter an institution they find the other pupils and the teachers using a form of gesture language which they do not understand. For the first time in their lives they find a language used by those about them that is addressed to the senses they possess. After a longer or shorter time they discard the lan- guage that they had themselves devised, and acquire, by imitation, the sign language of the institution. Harmful Results of the Sign Language. After a few months residence in the institution, the children re- turn to their friends in the holidays using easily and fluently a lan- guage that is foreign to them, while of the English language they know no more than the average school boy does of French or Ger- man after the same period of instruction. The only language they can employ in talking to their friends is the crude gesture language of their own invention, which they had long before discarded at school ; and they perpetually contrast the difficulty and slowness of comprehension of their friends with the ease with which their school fellows and teachers could understand what they mean. They have 72 PHILOSOPHICAL SOCIETY OF WASHINGTON. learned by experience how sweet a thing it is to communicate freely with other minds, and they are continually hampered and annoyed by the difficulty they meet with in conversing with their own parents and friends. Can it be wondered at, therefore, that such a child soon tires of home? He longs for the school play-ground, and the deaf com- panions with whom he can converse so easily. Little by little the ties of blood and relationship are weakened, and the institution be- comes his home. Nor are these all the harmful effects that are directly traceable to the habitual use in school, as a means of communication, of a language foreign to the mass of the people. Disastrous results are traceable inwards in the operation of his mind, and outwards in his relation to the external world in adult life. He has learned to think in the gesture-language, and his most perfected English ex- pressions are only translations of his sign speech. As a general rule, when his education is completed, his knowl- edge of the English language is like the knowledge of French or German possessed by the average hearing child on leaving school. He cannot read an ordinary book intelligently without frequent re- course to a dictionary. He can understand a good deal of what he sees in the newspapers, especially if it concerns what interests him personally, and he can generally manage to make people under- stand what he wishes by writing, but he writes in broken English, as a foreigner would speak. Let us consider for a moment the condition of a person whose vernacular is different from that of the people by whom he is sur- rounded. Place one of our American school boys just graduated from school in the heart of Germany. He finds that his knowledge of German is not sufficient to enable him to communicate freely with the people. He thinks in English, and has to go through a mental process of translation before he can understand what is said, or can himself say what he means. Constant communication with the people involves constant effort and a mental strain. Under such circumstances what a pleasure it is for him to meet with a per- son who can speak the English tongue. What a relief to be able to converse freely once more in his own vernacular. Words arise so spontaneously in the mind that the thought seems to evoke the proper expression. But mark the result: the more he associates with English- GENERAL MEETING. 73 speaking people the less desire does he have to converse in German. The practice of the English language prevents progress in the aquisition of German. I have known of English people who have lived for twenty years in Germany without acquiring the language. If our American school boy desires to become familiar with the German language, he must resolutely avoid the society of English- speaking people. He then finds that the mental effort involved in conversation becomes less and less, until, finally, he learns to think in German, and his difficulties cease. Now consider the case of a deaf boy just graduated from an institution where the sign language has been employed as a means of communication. His vernacular is different from that of the people by whom he is surrounded. He thinks in the gesture lan- guage and has to go through a mental process of translation before he can understand what is said or written to him in English, and before he can himself speak or write in English what he desires to say. He finds himself in America, in the same condition as that of the American boy in Germany. If he avoids association with those who use the sign language, and courts the society of hearing persons, the mental effort involved in conversation becomes less and less, and finally he learns to think in English and his difficulties cease. But such a course involves great determination and perseverance on the part of the deaf boy, and few, indeed, are those who succeed. Not only do the other deaf-mutes in his locality have the same vernacular as his own, but they were his school fellows, and they have a common recollection of pleasant years of childhood spent in each other's society. Can it be wondered at, therefore, that the vast majority of the deaf graduates of our institutions keep up acquaintance with one another in adult life ? The more they com- municate with one another the less desire they have to associate with hearing persons, and the practice of the gesture language forms an obstacle to further progress in the acquisition of the English language. These two causes (a) previous exclusive acquaintance with one another in the same school, and (b) a common knowledge of a form of language specially adapted for the communication of the deaf with the deaf, operate to attract together into the large cities large numbers of deaf persons, who form a sort of deaf community or society, having very little intercourse with the outside world. 74 PHILOSOPHICAL SOCIETY OF WASHINGTON. They work at trades or businesses in these towus, and their leisure hours are spent almost exclusively in each other's society. Under such circumstances can we be surprised that the majority of these deaf persons marry deaf persons, and that we have as a result a small but necessarily increasing number of cases of hereditary deafness due to this cause. Such unions do not gene- rally result in the production of deaf offspring, because the deaf- ness of the parents in a large proportion of cases is of accidental origin, and accidental deafness is no more likely to be inherited than the accidental loss of a limb. Still I would submit that the constant selection of the deaf by the deaf in marriage is fraught with danger to the community. Why the English Language should be Substituted for the Sign Language as a Vernacular. If we examine the position in adult life of deaf children who have been taught to speak, or who have acquired the English lan- guage as a vernacular, whether in its written or spoken forms, we find an entirely different set of tendencies coming into play, especi- ally if these persons have not been forced in childhood to make the acquaintance of large numbers of other deaf children, by social imprisonment for years together in the same school or institution apart from the hearing world. Their vernacular use of the English language renders it easy for them to communicate with hearing persons by writing, or by word of mouth if they have been taught to articulate ; and hearing per- sons can easily communicate with them by writing, or by word of mouth if they have been taught the use of the eye as a substitute for the ear. The restraints placed upon their intercourse with the world by their lack of hearing leads them to seek the society of books, and thus they tend to rise mentally to an ever higher and higher plane. A cultivated mind delights in the society of edu- cated people, and their knowledge of passing events derived from newspapers forms an additional bond of union between them and the hearing world. If they have formed in childhood few deaf acquaintances, they meet in after life hundreds of hearing persons for every deaf acquain- tance, and if they marry, the chances are immensely in favor of their marrying hearing persons. There is nothing in the deaf-mute societies in the large cities to GENERAL MEETING. 75 attract them, and much to repel them ; for the more highly edu- cated deaf-mutes in these societies speak what is to them a foreign language; while the greater number of the deaf-mutes to be found there are so ignorant that self-respect forbids them from mingling with them. Thus the extent of their knowledge of the English language is the main determining cause of the congregation or separation of the deaf in adult life. A good vernacular knowledge of the Eng- lish language operates to effect their absorption into society at large, and to weaken the bonds that tend to bring them together ; whereas, a poor knowledge of the language of the country they live in causes them to be repelled by society and attracted by one another ; and these attractive and repulsive tendencies are increased and intensified if they have been taught at school a language for- eign to society and specially adapted for intercommunication among themselves. I say, then, let us banish the sign language from our schools. Let the teachers be careful in their intercourse with their pupils to use English and English alone. They can write, they can speak by word of mouth, they can spell the English words by a manual alphabet, and by any or all of these methods they can teach English to their pupils as a native tongue. Conclusion. In conclusion allow me to say : 1. That those whom we term " deaf-mutes " have no other natural defect than that of hearing. They are simply persons who are deaf from childhood and many of them are only " hard-of-hearing." 2. Deaf children are dumb, not on account of lack of hearing, but of lack of instruction. No one teaches them to speak. 3. A gesture language is developed by a deaf child at home, not because it is the only form of language that is natural to one in his condition, but because his parents and friends neglect to use the English language in his presence in a clearly visible form. 4. (a) The sign language of our institutions is an artificial and conventional language derived from pantomime. (6) So far from being natural either to deaf or hearing persons, it is not understood by deaf children on their entrance to an insti- tution. Nor do hearing persons become sufficiently familiar with the language to be thoroughly qualified as teachers until after one or more years' residence in an institution for the deaf and dumb. 76 PHILOSOPHICAL SOCIETY OF WASHINGTON. (c) The practice of the sign language hinders the aquisition of the English language. (d) It makes deaf-mutes associate together in adult life, and avoid the society of hearing people. (e) It thus causes the intermarriage of deaf-mutes and the propagation of their physical defect. 5. Written words can be associated directly with the ideas they express, without the intervention of signs, and written English can be taught to deaf children by usage so as to become their ver- nacular. 6. A language can only be made vernacular by constant use as a means of communication, without translation. 7. Deaf children who are familiar with the English language in either its written or spoken forms can be taught to understand the utterances of their friends by watching the mouth. 8. The requisites to the art of speech-reading are : (a) An eye trained to distinguish quickly those movements of the vocal organs that are visible (independently of the meaning of what is uttered.) (b) A knowledge of homophenes ; * that is, a knowledge of those words that present the same appearance to the eye ; and (c) Sufficient familiarity with the English language to enable the speech-reader to judge by context which word of a homophe- nous group is the word intended by the speaker. If we look back upon the history of the education of the deaf, we see progress hindered at every stage by fallacies. Let us strive, by discussion and thought, to remove these fallacies from our minds so that we may see the deaf child in the condition that nature has given him to us. If we do this, I think we shall recognize the fact that the afflictions of his life are mainly due to ourselves, and we can remove them. Nature has been kind to the deaf child, man cruel. Nature has inflicted upon the deaf child but one defect—imperfect hearing ; man's neglect has made him dumb and forced him to invent a language which has separated him from the hearing world. Let us, then, remove the afflictions that we ourselves have caused. * This word was suggested to me some years ago by Mr. Homer, lately Prin- cipal of the Providence (R. I.) School for Deaf-Mutes, and has now been per- manently adopted. GENERAL MEETING. 77 1. Let us teach deaf children to think in English, by using English in their presence in a clearly visible form. 2. Let us teach them to speak by giving them instruction in the use of their vocal organs. 3. Let us teach them the use of the eye as a substitute for the ear in understanding the utterances of their friends. 4. Let us give them instruction in the ordinary branches of edu- cation by means of the English language. 5. And last, but not least, let us banish the sign language from our schools. If it were our object to fit deaf children to live together in adult life and hold communication with the outside world as we hold communication with other nationalities than our own, then no bet- ter plan could be devised than to assist the development of a special language suitable for intercommunication among the deaf. But if, on the other hand, it is our object to destroy the barriers that separate them from the outside world and take away the isola- tion of their lives, then I hold that our energies should be devoted to the acquisition of the English language as a vernacular in its spoken and written forms. With such an object in view we should bring the deaf together as little as possible and only for the pur- pose of instruction. After school hours we should separate the deaf children from one another to prevent the development of a .special language and scsftter them among hearing children and their friends in the outside world. The subject being presented to the Society for discussion, Mr. E. M. Gallaudet spoke, in substance, as follows : I have listened with great interest to the remarks of Mr. Bell this evening, and am ready to agree in many particulars with the views he has so Avell presented. I am, however, compelled to differ with him at several points ; and as these involve matters of vital importance in the treatment of the deaf, I will beg the indulgence of the Society for a short time, while I attempt to show to what extent some of Mr. Bell's views are erroneous. In proving the generally received opinion that the vocal organs of persons deaf from infancy are defective, to be a fallacy, Mr. Bell declared that difficulties encountered by such persons in acquiring speech are wholly external to themselves, and that all 78 PHILOSOPHICAL SOCIETY OP WASHINGTON. persons so situated can, with proper instruction, be taught to speak and to understand the motions of the lips of others. That this is a grave error has been proved by the experience of more than a century of oral teaching in Germany. The late Moritz Hill, of Wessenfels, Prussia, a man of the widest experience and highest standing among the oral teachers of Europe, expressed to me the opinion a few years since that out of one hun- dred deaf-mutes, including the semi-mute and semi-deaf, only " eleven could converse readily with strangers on ordinary subjects" on leaving school. Of course a much larger number would be able to converse with their teachers, family, and intimate friends on common-place subjects ; but it would be found that very many could never attain to any ready command of speech. The explanation of this lies in the fact that a child, deaf from infancy, in order to succeed with speech and lip-reading must pos- sess a certain quickness of vision, a power of perception, and a control over the muscles of the vocal organs, by no means common to all such children. Mr. Bell's view has been held by many instructors with more or less tenacity, and this fact is explained by a readiness on their part to argue from the particular to the general. Having attained marked success with certain individuals, they draw, in their enthusiasm, the mistaken conclusion that success is possible in the case of every other deaf child, overlooking the fact that many things, besides the mere deafness of the child, may affect the result. Experience has demonstrated that in attempting to teach the deaf to speak, failure in many cases must be anticipated. Mr. Bell is mistaken in supposing ignorance as to the mech- anism of the vocal organs to be a prominent cause of failure to impart speech to the deaf. It is no doubt true that among per- sons unfamiliar with the training of the deaf, few have made the mechanism of speech a study ; but in Germany, Italy, and France, not to speak of our own country, many are to be found who may be said to have mastered this subject. The results of their labors have been made available to instructors of the deaf, and all the best oral schools are profiting thereby. Mr. Bell is also mistaken when he says that " in a majority of our schools and institutions articulation and speech-reading are taught to only a favored few, and in these schools no use of articu- lation is made as a means of communication," and that " few, if GENERAL MEETING. 79 any, attempts are made to teach articulation to those who have not naturally spoken." In most of the larger institutions for the deaf in this country, every pupil is afforded an opportunity to acquire speech, and instruction in this is discontinued only when success seems plainly unattainable. It is a great error to suppose it to be true of a deaf person edu- cated on what Mr. Bell calls the sign-method, that, " as a general rule, when his education is completed, his knowledge of the English language is like the knowledge of French or German possessed by the average hearing child on leaving school," or to say that " he cannot read an ordinary book intelligently without frequent recourse to a dictionary." On the contrary, a majority of persons thus educated have a good knowledge of their vernacular, are able to use it readily as a means of communication with hear- ing persons, and are able to read intelligently without frequent recourse to the dictionary. When Mr. Bell has become familiar with the peculiarities of the deaf by personal contact with a large number of this class of persons, I am confident he will not repeat his assertion that " nature has inflicted upon the deaf child but one defect—imperfect hearing." For he will then have discovered, what has long been known to teachers of experience, that deaf children, in addition to their principal disability, are often found to be lacking in mental capacity, or in the imitative faculty, in the power of visual or tactile perception, and in other respects; all of which deficiencies, though they do not amount even to feeble-mindedness, much less to idiocy, do operate against the attainment of success in speech, as well as in other things which go to complete the education of such chil- dren. . Passing over several points of relatively small importance, in regard to which I believe Mr. Bell's views to be subject to criti- cism, I come to his characterization as a fallacy of the opinion held by many " that the language of gestures is the only language natural to the child born deaf or who has become deaf in infancy." I think that in order to sustain his view that this is a fallacy Professor Bell gives a strained and very unusual meaning to the words " natural language." If, as he explains, a natural language is any one that a child may happen to be first taught by those with whom he is associated, then I should have no controversy with him. But I understand a natural language to be one that is mainly spon- taneous, and not at all one that is borne in upon a child from without. 80 PHILOSOPHICAL SOCIETY OF WASHINGTON. Moritz Hill, to whom I have already alluded, speaks of the lan- guage of signs as " one of the two universally intelligible innate forms of expression granted by God to mankind," the other being speech. Now it is hardly necessary to urge that speech is the form of expression natural to hearing persons, and I think a little re- flection will satisfy most persons that with the deaf the language of signs is the only truly natural mode of expressing their thoughts. Mr. Bell urges that the use of signs in the education of the deaf is a hinderance rather than a help, and that it would be better to banish them altogether. To this view I must give my earnest dissent. I might, of course, cite the opinions of very many successful in- structors of the deaf, who have followed only the sign method, to sustain my position, but I prefer to call in again the testimony of Moritz Hill, a man whose whole life was devoted to the instruction of the deaf by the oral method. In an exhaustive work on the education of the deaf,* Hill says, speaking of those who pretend that in the " German method " every species of pantomimic language is proscribed : " Such an idea must be attributed to malevolence or to unpardon- able levity. This pretence is contrary to nature and repugnant to the rules of educational science. " If this system were put into execution the moral life, the in- tellectual development of the deaf and dumb, would be inhumanly hampered. It would be acting contrary to nature to forbid the deaf-mute a means of expression employed by even hearing and speaking persons. * * * It is nonsense to dream of depriving him of this means until he is in a position to express himself orally. * * * Even in teaching itself we cannot lay aside the lan- guage of gestures (with the exception of that which consists in artificial signs and in the manual alphabet—two elements proscribed by the German school), the language which the deaf-mute brings with him to school, and which ought to serve as a basis for his edu- cation. To banish the language of natural signs from the school- room and limit ourselves to articulation is like employing a gold key which does not fit the lock of the door we would open aud refusing to use the iron one made for it. * * * At the best, it would be drilling the deaf-mute, but not moulding him intellectually or morally." * Der gegenwartige Zustand des Taubstummen Bildungswesens in Deutsch- land; von Hill, Inspector der Taubstummen Anstalt zu Wetssenfels; Ritter des St. Olafs, &c. Weimar, H. Bohlau, 1 866. GENERAL MEETING. 81 Hill then follows with thirteen carefully formulated reasons why the use of signs is important and even indispensable in the educa- tion of the deaf. Mr. Bell is in error when he supposes that in the so-called sign- schools verbal language is only imparted through the intervention of the sign-language. In many well-ordered schools of this class, language is taught without the use of signs, and in such schools the language of signs is kept in its proper position of subordination. It goes without saying that in schools for the deaf there may be an injudicious and excessive use of signs. This is always to be guarded against, and when it is, I am convinced that no harm, but great good, results from the use of signs in teaching the deaf. Furthermore, it is well known that the attempt to banish signs from a school for the deaf rarely succeeds. Miss Sarah Porter, for three years an instructor in the Clarke Institution at Northamp- ton, Mass., an oral school in which most excellent results have been attained, shows candor as well as judgment when she says, in a re- cent article in the American Annals of the Deaf and Dumb, " Every oral teacher knows that fighting signs is like fighting original sin. Put deaf children together and they will make signs secretly if not openly in their intercourse with each other." It is not true as a matter of fact that the use of signs necessarily prevents the deaf from acquiring an idiomatic use of verbal lan- guage and from thinking in such language. Large numbers of them who have never been taught orally have come into such a use of verbal language, and while it is granted that many edu- cated under the sign system do not use verbal language freely and correctly, the same is found to be true of very many who have been educated entirely in oral schools. In one important particular the language of signs performs a most valuable service for the deaf, and one of which nothing has yet been found to take the place. Through signs large numbers of deaf persons can be addressed, their minds and hearts being moved as those of hearing persons are by public speaking in its various forms. Having seen the good effects on the deaf of the discreet use of the sign-language through a period of many years, I am confident that its banishment from all schools for the deaf would work great injury to this class of persons intellectually, socially, and morally. 82 PHILOSOPHICAL SOCIETY OP WASHINGTON. The Hon. Gardiner G. Hubbard being present, was invited by the chair to participate in the discussion. He said he had been connected with the Clark Institution for many years. The deaf pupils in that school are taught entirely by articulation. From recent inquiries which had been made to ascertain how far the graduates had profited by instruction in articulation, it ap- peared that in almost in every instance they could carry on conver- sation with others sufficiently to engage in many kinds of business from which they would have been excluded if they had only used signs. It was true, as Mr. Gallaudet said, the congenitally deaf were fre- quenty able to articulate more distinctly than those who lost their hearing at an early age, but this arises from the fact that the dis- ease that caused the deafness affected the organs of articulation to a greater or less degree ; but the congenitally deaf do not make as rapid progress in their studies as those who had once spoken, for these have a knowledge of language which the former could ob- tain only by long protracted study. Mr. Hubbard believed that the pupils at the Clark Institution made at least as rapid progress in all their studies as those taught by signs ; while, at the same time, they acquired the power of read- ing from the lips and speaking, in which those taught by signs were deficient. When the first application was made to the Legislature of Mas- sachusetts for the incorporation of the Clark Institution, Mr. Dud- ley, of Northampton, chairman of the committee to whom the peti- tion was referred, had a congenitally deaf child under instruction at Hartford. The petitioners were opposed by the professors from the asylum, as they believed an articulating school would retard the education of the deaf, as it was impractical to teach the deaf by articulation, that system having been tried and proved a failure, and the new method was stigmatized as one of the visionary theories of Dr. Howe, (the principal of the Perkins Institute for the Blind, and the teacher of Laura Bridgeman, the blind deaf mute,) who was associated with the petitioners in the hearing. The application was rejected through the influence of these pro- fessors and of Mr. Dudley, who ' knew, from experience with his own child, that it was impossible to teach the congenitally deaf to talk.' Two years after, our application was renewed and with better success. GENERAL MEETING. 83 Mr. Hubbard in the meantime, with the aid of Miss Rogers, had opened a small school where the deaf were taught to speak. This school was visited and examined by the committee, and the progress made was so great that Mr. Dudley became a warm convert, con- vinced that the impossible was possible, and the application was granted, although again opposed by the gentlemen from Hartford. The school was opened at Northampton, and has been in operation for nearly fifteen years, and teaching by articulation has ceased to be a visionary theory. Many of the warmest friends of the Institution now are, like Mr. Gallaudet, connected with institutions where signs are used. In almost every institution for the deaf classes are now taught to articu- late, though articulation is not used as the instrument for instruc- tion. Mr. Gallaudet had taken exception to the remark of Mr. Bell, that idiots were born dumb, and said that in every school for idiots there were many feeble-minded children who could talk readily; but Mr. Bell used the word idiot not as simply a feeble-minded person, but according to its ordinary meaning, " a human being destitute of reason or the ordinary intellectual powers of man." It has always been the policy at Northampton to prevent, as far as possible, marriages of deaf with deaf, for the records show that the children of such intermarriages are often deaf; and even where a congenitally deaf person marries a hearing person, the children sometimes are deaf. The tendency of the intermarriage of the deaf would be to raise a deaf race in our midst. About one in 1,500 of the population are deaf; but if these in- termarriages should take place and a deaf race be created, the propor- tion would rapidly increase. The object of all friends of the deaf should be to prevent the deaf from congregating, and to induce them to associate with hearing people. In bringing the deaf to- gether in institutions, where they are taught by signs, the tendency is to make the deaf deafer and the dumb more dumb. It was originally intended to have only a family or small school at Northampton, but it was soon found that signs could not be ex- cluded from the play-ground, as the young children could not com- municate in any other way. The plan was changed, the number of pupils was largely increased, and a preparatory department estab- lished, in which signs were tolerated on the play-ground. On 84 PHILOSOPHICAL SOCIETY OF WASHINGTON. the removal of the pupils to the higher departments, the use of signs is forbidden, and they are rarely used on the play-ground or between the pupils, either in or out of school hours. In the later years of instruction they acquire great facility in articulation and reading from the lips, though there is almost always some difficulty for a stranger to understand them. Mr. Gallaudet had referred to the International Convention of deaf-mute teachers and their friends, at Milan, three years ago. Mr. Hubbard was present at the convention held this year at Brussels, and was there informed that a delegate had been sent from France to attend the convention at Milan and investigate the method of in- struction in Italy, where articulation was used, for the purpose of deciding whether the instruction in the French schools should con- tinue to be by signs, or instruction by articulation be substituted for signs. The preference of the delegate had been for signs, but on witness- ing the results obtained in the Italian schools and hearing the dis- cussion, he was led to advise that the instruction in the French schools hereafter be by articulation, instead of signs, and such a change has, Mr. Hubbard understands, been made in most of the schools of France. Mr. Hubbard learned from the reports at Brussels that almost all the European schools were taught by articulation, and that this means of instruction was being rapidly substituted for the sign language in England as well as in France. Mr. Bell, in reply to the remarks of Mr. Gallaudet, said : There are signs and signs. There is the same distinction between pantomime and the sign-language that there is between a picture and the Egyptian hieroglyphics. Pictures are naturally understood by all the world, but it would be illogical to argue from this that a picture-language, like that de- veloped by the ancient Egyptians, must also be universally intelli- gible. Pantomime is understood by all the world, but who among us can understand the sign-language of the deaf and dumb without much instruction and practice? No one can deny that pantomime arid dramatic action can be used, and with perfect propriety, to illustrate English expressions so as actually to facilitate the acquisition of our language by the deaf; but the abbreviated and conventionalized pantomime, known GENERAL MEETING. 85 as the " sign-language," is used in place of the English language, and becomes itself the vernacular of the deaf child. Judging from the quotations given by Dr. Gallaudet, Moritz Hill himself makes a clear distinction between pantomime and the sign-language, retaining the former and proscribing the latter. " Every species of pantomimic language is not proscribed," he says. " Natural signs," or " signs employed by hearing and speak- ing persons," are retained, while "artificial signs " are proscribed. All the arguments that have been advanced regarding pantomime and a pantomime language are equally applicable to pictures and a picture-language. For instance, we may say that a picture- language is more natural than any of the spoken languages of the world, because pictures are naturally understood by all mankind. We may even arrive, by a further process of generalization, at the idea that picture-language, in the wider sense, really constitutes the only form of language that is natural at all, for all the other languages of the world appear to be entirely arbitrary and conven- tional. If we pursue the parallel we shall arrive at the conclusion that a picture-language of some kind must necessarily become the vernacular of our pupils, through which the other more conventional languages may be explained and taught. It is immaterial whether such statements are fallacious or not, so long as we do not apply them to educational purposes. But let us see how they work in practice. The exhibition of a picture undoubtedly adds interest to the fairy tale or story that we tell a child. It illustrates the language we use, and it may be of invaluable assistance to him in realizing our meaning. But is that any reason why we should teach him Egyptian hieroglyphics ? Granting the premises : Is the conclusion sound that we should therefore teach him English by means of hieroglyphics ? If such conclusions are illogical, then the fundamental ideas upon which our whole system of education by signs is based are also fallacious and unsound. One word in conclusion regarding speech. The main cause of the fallacies that fog our conception of the condition of the deaf child is his lack of speech. A deaf person who speaks is regarded by the public more as a foreigner than as a deaf mute. Speech, however imperfect, breaks through the barriers of prejudice that separate him from the world, and he is recognized as one of ourselves. 86 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. Gallaudet under-estimates the value of speech to a deaf child. He seems to think that speech is of little or no use, unless it is as perfect as our own. The fact is that the value of speech to a deaf child must be measured by its intelligibility rather than by its perfection. It is astonishing how imperfect speech may be and yet be intelli- gible. We may substitute a mere indefinite murmur of the voice for all our vowel sounds, without loss of intelligibility. (Here Mr. Bell spoke a few sentences in this way, and was perfectly understood.) Here at once we get rid of the most difficult elements we are called upon to teach. If now we examine the relative frequency of the con- sonantal elements, we shall find that 75 per cent, of the consonants we use are formed by the point of the tongue, and that the majority of the remainder are formed by the lips. The consonants that are difficult to teach are chiefly formed by the top or back part of the tongue ; but, on account of their comparative rarity of occur- rence, they may be very imperfectly articulated without loss of intelligibility. Hence I see no reason why, in spite of the general ignorance of teachers respecting the mechanism of speech, we may not hope to teach all deaf children an intelligible pronuncia- tion. Let teachers appreciate the value of intelligible speech to a deaf child, and they will make the attempt to give it to him. At the present time, lack of appreciation operates to prevent the attempt from being made upon a large scale. Skilled teachers of articula- tion will become more numerous as the demand for their service increases, and their ingenuity, intelligently applied, will increase the perfection of the artificial speech obtained. In the meantime, do not let us discard speech from the difficulty of obtaining it in perfection. Do not let us be misled by the idea that intelligible but defective speech is of no use, and must necessarily be painful and disagreeable to all who hear it. Those who have seen the tears of joy shed by a mother over the first utterances of her deaf child will tell you a different tale. None but a parent can fully appreciate how sweet and pleasant may be the imperfect articu- lation of a deaf child. 240th Meeting. November 10, 1883. The President in the chair. Forty-eight members present. GENERAL MEETING. 87 Announcement was made of the election to membership of Ethelbert Carroll Morgan. It was announced from the General Committee that invitation had been extended to the members of the Anthropological and Biologi- cal Societies to attend the meeting of December 8th, for the pur- pose of listening to the annual address of the President. Mr. Edwin Smith exhibited a SEISMOGRAPHIC RECORD OBTAINED IN JAPAN, describing the apparatus by which it was made, and giving a brief account of the seismographic investigations of Professor J. A. Ewing. Remarks were made by Mr. Antisell. Mr. C. E. Dutton made a communication, entitled the volcanic problem stated. [Abstract.] It is sufficiently obvious that the volcano is a heat problem, or a thermo-dynamic problem. All volcanic activity is attended with manifestations of great energy. This energy is due to the elastic force of considerable quantities of water occluded in red-hot or yellow-hot lavas. The problem is to find a satisfactory explanation of the origin of the heat, the origin of the occluded water, and their modes of reaction. In attempting this solution, various explanations have been con- jectured. The first to be noticed, and the one which, in various forms, has met with the most favor from geologists and physicists, is that the source of heat is primordial — i. e., it is the remains of a large amount of heat contained by the entire earth-mass in its sup- posed primordial condition, according to the nebular hypothesis ; that water has penetrated from above, either from the ocean or from lakes ; and that the contact of cold water with the hot magmas within the earth is a summary explanation of the phenomena. This view is supported by the following considerations : 1st, the contact of water with intensely hot bodies and the resulting generation of great explosive force is matter of the commonest experience ; 2d, the outer rocks and strata are known to be full of fissures, and the ocean bottom and lake bottoms are, therefore, presumably very leaky ; 3d, nearly all active volcanoes are situated either within, or 88 PHILOSOPHICAL SOCIETY OF WASHINGTON. in the neighborhood of, large bodies of water ; 4th, volcanoes near the sea often deliver salts which may reasonably be supposed to be the same as those contained in the ocean ; 5th, the analogy of gey- sers gives us a series of phenomena which seem to be, in many respects, quite parallel, and which have been satisfactorily explained in a similar way. To this view of the origin and causation of volcanic activity there are some objections. There is difficulty in understanding how water obtains access to hot magmas. No doubt the rocks are full of fissures, but we cannot, by any means, confidently infer that these fissures extend sufficiently deep to afford free or even capillary pas- sages to melted magmas beneath. We should more legitimately infer that the heat increases gradually with the depth. At a depth of a few miles the rocks presumably have a temperature which, though high, is still below fusion, and at such temperatures it is well known that all the siliceous or rocky materials we are acquainted with are viscous. Remembering the immense statical pressure due to a thickness of a single mile of rocks, all fissures at such depths would be closed, as if the rocks were wax or butter. 2d. Although the contact of cold water with intensely hot masses will surely produce a violent explosion, we are not at liberty to admit offhand that cold water does obtain such contact in the volcanoes. On the contrary, as it penetrates it takes up the heat of the rocks through which it passes. But water is believed by all physicists to have what is technically termed a critical temperature, i. e., a tem- perature at which it can exist only in the form of vapor however great the pressure, and this temperature is computed theoretically to be about 772° F., which is far below that of melted rock. If therefore, water could reach the liquid lavas below, it would reach them only in the form of vapor. There is indeed no difficulty in supposing that the vapor of water may, under great statical pres- sure, be forced into the rocks, passing between inter-molecular spaces. This is but one aspect of the phenomena of the diffusion and occlu- sion of gases in solids, and we know that water-vapor in large quan- tities is readily occluded by lava. But this is evidently no explan- ation of the explosive action. It is in the broadest possible con- trast with the gross conception of the sudden access of cold water to hot bodies. The presumption is, under the process here sug- gested, that the vapor of water might penetrate slowly into regions of great heat until the hot magmas were saturated, and then the GENERAL MEETING. 89 process would come to a standstill. But there would be no volcano in this case, for the supposed condition is evidently statical and stable. For the pressure which is supposed to force the vapor in is that due to the hydrostatic pressure of a column of water. The pressure which keeps it from blowing out is that due to an equally high or even higher column of rock, the density of which is at least two and a half times greater. 3d. The analogy of the geyser thus fails to become a true ho- mology, or an epitome of the volcano. For the geyser is due to the access of cold water to a cavity walled by hot rocks and its vapor- ization ; the volcano, if due to the penetration of water, is due to pen- etration in the form of vapor in the first instance ; and the difference is radical. 4th. The proximity of volcanoes to large bodies of water does not necessarily imply a logical and causal relation, and is not nec- essarily the true law of distribution. Another and perhaps a more rational law of distribution may be given. As a matter of fact all active volcanoes are not situated near seas or lakes, though in truth the exceptions are at the present time few, as for instance, Sangay, in the eastern Cordilleras of Peru, and the volcanoes of Central Asia. It seems as if Darwin had acutely divined the true associa- tion, viz : that volcanoes are situated in areas which are undergoing elevation. So far as we know this rule is without exception, but there are many cases where the verification of the elevation is want- ing. So far, however, as the test has hitherto been applied it has approved the rule. This is especially conspicuous in the western half of our own country when applied to the late Tertiary and Post Tertiary volcanoes, and it is true, so far as known, of the Andes, Java, Philippines, and Mediterranean, and I have recently been able to verify it in the case of the Hawaiian volcanoes. It happens that elevations, as well as subsidences, are much more frequent and extensive near coast lines than in continental interiors, whence the proximity of volcanoes to the sea becomes a secondary rather than a primary relation. But elevations also occur in continental in- teriors, though less frequently. And when they do occur, we find associated phenomena of volcanism as abundant and forcible as in littoral regions. This has been the case in the great Tertiary ele- vation of the Rocky Mountains, of the Alps, and of the Himalayan plateau. Darwin's law of the distribution of volcanoes is as thor- oughly sustained by geological history as by modern instances; 10 90 PHILOSOPHICAL SOCIETY OF WASHINGTON. while the other law, though largely predominant at the present period, shows a few conspicuous failures at the present time, but a very large number of them in times past. Another hypothesis to account for volcanic energy supposes the interior of the earth to consist of unoxidized elements, which grad- ually become oxidized by the penetration of oxygen from the at- mosphere. The objections to this hypothesis are as follows : On the assump- tion that the earth acquires no oxygen from space, the primitive atmosphere would have been many thousand times greater than at present ; but the geological record argues strongly in favor of an atmosphere which may indeed have varied in quantity and compo- sition, but nowhere near so greatly as the hypothesis implies. Any such extravagant difference would have recorded itself legibly in the strata. Furthermore, on this view, the end of all volcanic ac- tivity is close at hand. Only three pounds of oxygen to the square inch of terrestrial surface are left. A few hundred or thousand centuries and the last volcanic beacon is extinguished, and with it all organic life. But suppose the earth gathers up oxygen in its march through space. This may be true, but we can make any supposition on this point which pleases our fancy and feel sure that no prudent scien- tific man will dispute it. A third hypothesis is that of the late Robert Mallet, which as- sumes the earth to be contracting interiorly by a secular loss of prim- itive heat. As the interior cools and shrinks, the external shell is crushed and crumpled together, and this mechanical crushing is a sufficient source of heat. To this hypothesis there are many answers. The most direct one is that the very facts which are relied upon to prove that there is any interior cooling at all now going on also prove that the amount hitherto has been excedingly small, and has been limited as yet to a thin external shell, not exceeding 150 miles in thickness, while the great interior is about as hot as ever ; but, by the terms of the hypothesis, if the interior has not cooled there has been no interior contraction. The hypothesis is refuted by taking its own premises and pushing them to their inevitable conclusions. There is a fourth hypothesis, which cuts the Gordian knot in- stead of untying it. It assumes, as the result of causes unexplained, heat is generated locally within the earth, and such local movements GENERAL MEETING. 91 of heat are the cause of volcanism. This is an arbitrary postulate, which, by its own terms, precludes discussion. Nevertheless it is the one which I believe agrees best, and perhaps perfectly, with ob- served facts. It undoubtedly sweeps away the difficulties which encumber all other hypotheses, but unfortunately it is an appeal to mystery, and therefore substitutes a single difficulty as great as, if not greater, than all the other difficulties put together. There is a fifth hypothesis, which takes account of the fact that many bodies which are solid under great pressure are immediately liquefied when the pressure is removed, heat being neither lost nor gained. The removal of pressure by denudation of the surface above the seat of lavas may thus determine volcanic action. The reply to this is that volcanoes do not always, nor even generally, occur where such denudation and consequent relief of pressure, are in progress. The true law of the distribution of volcanoes appears to be the one given by the late Charles Darwin, viz., that they occur in areas which are undergoing elevation. There are several broad facts, or categories of facts, which a true theory of the volcano must cover, and which will be recited briefly. 1. Lavas, in their subterranean seat, could not possibly have been in a highly elastic explosive condition from the earliest epochs of the earth's evolution, and only waiting a convenient season to break forth. We have no alternative but to regard them as being inert and inexplosive in their primitive condition, and as having acquired explosive energy just before the epoch of eruption. To assume that they have always been in the condition they present while pouring forth, and that the opening of a fissure has been the accident which determined the eruption, is reasoning in a circle. It is the energy of the lavas which causes the fissure, and not the fissure which causes the lavas to extrude. The lavas extrude themselves by vir- tue of their acquired elastic force. The theory must explain how materials which antecedently were inert, passive, incapable of erup- tion, may become active, dynamical, eruptible. 2. Another broad fact, closely related to the foregoing, is the in- termittent action of volcanoes. These vents do not discharge all their available products at once, but by repeated spasms of activity, separated by longer intervals of repose. If these fiery explosive liquids had lain so long in the earth, chock-full of energy and only awaiting the opening of a passage-way, how happens it that when 92 PHILOSOPHICAL SOCIETY OP WASHINGTON. a vent is once opened they do not all rush forth 'at once, and con- tinue to outpour until the reservoir is completely exhausted, and why does not the vent thereafter close up forever ? In a word, why should a volcano dole out its products in driblets, instead of send- ing forth one stupendous belch, equal to all the driblets combined ? The answer here proposed is that it is because lavas, in their primi- tive condition, do not have sufficient potential energy, in the form of elastic force, to break open the covering which keeps them in ; but they gradually acquire that energy in a portion of the reser- voirs at a time, and when a sufficient portion of them has acquired it the covering is ruptured, and the whole of this energetic portion is extravasated. The vent then closes, and the process is repeated upon a second installment. The agency which thus progressively develops this force is the missing factor, and when we discover it we shall discover the secret of the volcano. The third general fact to be taken account of is the enormous quantity of heat given off by volcanoes through long periods of time without any sign of exhaustion. The quantity of heat brought up by the lavas themselves is but a fraction of the whole amount dissipated. Kilauea wastes many times more heat by quiet radia- tion from the surfaces of its lava lakes and by steaming and by numberless modes of escape than by actual eruption of lavas. Mauna Loa also dissipates the greater part of its heat in the same way, and the same fact is wholly or partially true of all other active or intermittent volcanoes. And yet for very long periods, for thou- sands of centuries, these great volcanoes show no sign of heat-exhaus- tion ; on the contrary, such indications as we have suggest the con- clusion that the earth benegth them is hotter than before. A fourth general fact is that volcanoes are located in areas which have recently been or are now undergoing elevation. All these facts suggest the action of some cause generating heat within the earth. This cause, if such it be, is for the present wholly mysterious and unknown. Mr. Powell, referring to the relation between volcanic eruption and elevation, said that the typical, secular sequence of geologic events was, first, elevation, resulting in, second, degredation, accom- panied by, third, extravasation, followed sooner or later by, fourth, subsidence, resulting in, fifth, sedimentation. There are numerous regions in which this circle of events has been recorded, and in some places it has been repeated two or three times. GENERAL MEETING. 93 Mr. F. W. Clarke suggested that the difficulty in the way of a chemical explanation of volcanic phenomena was due to our ignor- ance of chemical force under high pressures. Spring has lately shown that chemical union could be brought about by pressure alone. Hence, water coming in contact with molten rock matter in the interior of the earth might be prevented from dissociating. If, however, dissociation takes place, we may conceive that water may play the following part in volcanic explosions. Gradually filtering through the surface rocks to the hot lava, it would undergo slow decomposition, and great quantities of mixed oxygen and hy- drogen would thus slowly accumulate. Now let a process of cool- ing begin. Soon the temperature at which oxygen and hydrogen unite would be reached, and explosive union would occur. This may account for volcanic explosions, at least in part. By such a process, potential energy is gradually stored up, to be later, sud- denly or instantaneously, released. This hypothesis does not ac- count for volcanic heat, but presupposes its existence. Mr. White, referring to Mr. Powell's remarks on the instability of continental areas, said that the prevalent doctrine of the perma- nence of oceans, and the gradual development of the continents? was not sustained by paleontology. Continents were needed some- where to develop the land plants and land mammals which ap- peared during the emergence of the known continents. Mr. Harkness pointed out that Mr. White was postulating un- known continents to support the Darwinian hypothesis, to which Mr. White assented. Mr. Powell added, that in detailing the great cycle of geologic events, he should have included metamorphism as a sixth term, re- sulting from burial by sediment ; and Mr. Dutton remarked that he had included this consideration in a paragraph contained in his written manuscript, but not read. Mr. McGee made a communication on THE DRAINAGE SYSTEM AND THE DISTRIBUTION OF THE LOESS OF EASTERN IOWA. [Abstract.] The most conspicuous geographic feature of eastern Iowa is the remarkable parallelism among its water-ways. Yet the region comprises two essentially distinct geologic tracts ; and the coincidence 94 PHILOSOPHICAL SOCIETY OF WASHINGTON. in direction of drainage in these is fortuitous : 1. The Wisconsin Driftless Region so far extends into the northeastern corner of Iowa as to include all of the triangular area bounded on the southwest by the elevated Niagara escarpment extending from the extreme eastward projection of the state northwestwardly to the Minnesota line, fifty miles west of the Mississippi. Within this tract, the drain- age was originally determined by general surface slope and by rock- structure, and the present topography, which is varied and pictu- resque, was developed by sub-serial erosion. 2. Within the far more extensive tract formed by the glacial drift and its derivatives, the surface is a gently undulating plain, over which the general relief is inconspicuous, and the local topography faintly defined though singularly uniform and symmetric in character ; and here the par- allelism in drainage is prevalent and characteristic. There are, in- deed, both local and general exceptions to this parallelism, which exemplify a variety of types of aberrant behavior of the streams ; but while these impair the geographic symmetry of the drainage system, they add much more largely to its geologic significance- Putting together the instances of accordant, and neglecting the in- stances of aberrant extension of water-lines, a normal direction oj drainage for the whole of the drift-formed tract might be empiric- ally determined ; which normal direction is represented by a sym- metric series of slightly divergent and slightly curved lines, concave to the northeastward, radiating from a point north of the state in a general southeasterly direction, toward the Mississippi. Probably nowhere else on the surface of the globe does so symmetric a normal drainage system exist, and assuredly nowhere else does the sum of directions of stream-flow over so considerable an area present so few examples of departure from the normal. The broader topographic features of eastern Iowa are dependant upon geologic structure. The dip of the rocks is to the southwest, and the outcrops of the several formations represented form suc- cessive approximately parallel zones (trending northwest and south. east), of which those of the Niagara and Hamilton are widest. Now the Niagara rocks resisted well the planation of the pre-quaternary eons, and their eastern margin is accordingly defined by a promi- nent escarpment varying from 1,000 to 1,350 feet in altitude, from which there is a steep northeasterly slope to the Mississippi, and a gentle inclination, corresponding to the dip of the strata, in the op- posite direction. The Hamilton rocks, on the other hand, have so GEjSLERAL meeting. 95 yielded to erosion that their area is topographically represented by a broad, shallow trough, of which the altitude is only from 600 to 1,000 feet, and of which the sides rise and culminate in the Niagara escarpment on the east and in the Mississippi-Missouri water-shed on the west. There is, however, a subordinate general topographic feature which is independent of geologic structure. A wide, gentle, indefinitely outlined depression extends directly across the great eastward projection (the " Cromwell's Nose ") of Iowa and diagonally across the Upper Silurian, Devonian, and Carboniferous rocks alike, in the line of the general course of the Mississippi, from near the' mouth of the Turkey to the mouth of the Iowa. It is manifestly of great antiquity. Thus, in its general topography, eastern Iowa is characterized, primarily, by an elevated escarpment near its eastern border, by a broad depression intersecting its western portion diagonally, and by a general southwesterly slope extending over most of its area ; and secondarily, by an indefinite ancient valley cutting off its eastern pi'ojection. And its general drainage system is almost absolutely independent of this general topography ; for not only do the prin- cipal streams flow at right angles to the prevailing slope and cut through the elevated escarpment when it lies in their way, but, with the single exception of the Cedar, they preserve their courses directly across the ancient valley. In their relation to minor topographic features the rivers of eastern Iowa conform to two diametrically opposite laws: 1. for two-thirds or three-fourths of their combined length they flow in the axes of the ill-defined, shallow valleys which characterize the drift-plain ; and, 2, for the remaining portion of their courses they flow in narrow gorges which they have excavated for themselves in the axes of the elongated ridges that constitute the leading features in the local topography of the region. Moreover, they have in many instances, at the same time gone out of their direct courses, and deserted valleys already prepared for them, to attain the anoma- lous positions assumed under the second law of association. And let it be noted that in every such case the gorges have demonstrably been carved by the streams themselves through the quaternary and older formations alike ; that the pre-existent valleys which they avoided have not been appreciably eroded since the quaternary ; and that there has been no localized orographic movement in the region since long antecedent to the quaternary. 96 PHILOSOPHICAL SOCIETY OF WASHINGTON. The principal tributaries entering the rivers from the right simi- larly conform to two antagonistic laws in their relation to topog- raphy : 1. Most of them flow throughout their courses in directions coincident with local and general slopes, and avoid elevations in their vicinity ; and, 2. Many of them originate with directions ap- proaching those normal to their localities, but curve more and more to the left toward their mouths, until they flow directly against the general slope, and enter the rivers at large angles ; and all such streams have high north banks which they closely hug, and low south banks which they avoid. So the drainage system of eastern Iowa is essentially independent of the more general topographic features, though affected by local topography ; and the relations of the waterways to local topography are largely anomalous, and without parallel elsewhere. Though essentially continuous stratigraphically, and of unques- tionable genetic unity, the loess of eastern Iowa is variable in many characters, and may be separated into three geographic divisions; viz: 1, the Driftless Region division; 2, the Riparian division; and, 3, the Southern division. That of the first division forms the surface throughout the Driftless Region, as it exists in Iowa, and everywhere overlaps the eastern border of the drift ; it is generally rather coarse, heterogeneous, and non-calcareous, and yields depau- perate fossils of characteristic species ; it reposes upon or gradu- ates into a thin stratum of water-worn erratic materials, which, in turn, rests upon either the residuary clays of the Driftless Region or the margin of the drift-sheet ; its western border is exceedingly sinuous, affects the greatest altitudes, and invariably overlooks the contiguous drift-plain ; and, in capping the elevated Niagara escarp- ment, it forms the highest land within hundreds of miles, except in northerly directions. The loess of the Riparian division occurs chiefly in the elongated ridges so common and so intimately asso- ciated with the waterways in eastern -central Iowa ; it is often fos- siliferous, and its characters are generally typical ; it usually grad- uates downward into stratified sands or gravels, which may or may not merge into drift; and it invariably seeks the highest summits in the region;—for the ridges in which the rivers have carved their canons are always loess-topped ; wherever streams avoid low-lying valleys for high-lying plateaus, the plateaus are of loess exteriorly; and the high northern banks of the aberrant tributaries are gen- erally loess-capped. The loess of the Southern division prevails GENERAL MEETING. 97 over southeastern Iowa ; it abounds in characteristic fossils (which may or may not be depauperate), in loess-kindchen, and in calcare- ous tubes ; it is fine, homogeneous, and vertically cleft ; it generally graduates into the subjacent drift so imperceptably that neither geographic nor stratigraphic separation of the formations, by other than a purely arbitrary line, is possible ; and it occurs indiscrimi- nately at all levels. So, in its distribution, the loess of eastern Iowa is intimately con- nected with the Driftless Region, with the drainage, and with the topographic configuration ; but in its disposition to seek the greatest altitudes in the north, and to merge into the drift in the south, its behavior is as anomalous as is that of the rivers of the same region. Mr. Powell remarked that these peculiarities of drainage were different from those observed in the drainage systems of mountain regions and demanded a different explanation, which was not yet forthcoming. It was probable, however, that not enough allowance was made for the differential effects of general degradation subse- quent to the determination of the drainage. Mr. Gilbert, after defining antecedent and super-imposed drain- age, said that Mr. McGee's description definitely negatived the hy- pothesis of antecedent drainage, and rendered the hypothesis of super-imposed drainage in the ordinary sense equally untenable. The most plausible alternative is the hypothesis suggested by Mr. McGee in one of his earlier papers, that the draiuage was super- imposed by the ice-sheet, the distribution of loess having been de- termined at the same time and by the same causes. Mr. "White regretted that Mr. McGee's special investigations did not include the portion of Iowa draining to the Missouri. The details of drainage iu that region are equally interesting, and, in his opinion, do not admit of the explanation mentioned by Mr. Gilbert. The direction of the rivers diverges at right angles from that of the Mississippi tributaries, and their valleys are excavated from loess except along their upper courses. Mr. Powell said that on the Illinois side of the Mississippi River many of the features described in the paper are repeated. The loess hills follow the river courses, and in the opposite directions over- look plains. The explanation of the phenomena is problematic, but the theory advocated by Mr. Gilbert does not appear sufficient. 98 philosophical society of washington. 241st Meeting. November 24, 1883. Vice-President Billings in the Chair. Fifty-three members and guests present. It was announced by the Chair that the next meeting would be held in the Lecture Hall of the National Museum, that the mem- bers of the Anthropological and Biological Societies were invited to be present, and that the members of all three societies were re- quested to invite their friends. Opportunity was afforded for the introduction of amendments to the Constitution, but none were offered. Mr. C. D. Walcott made a communication on THE CAMBRIAN SYSTEM IN THE UNITED STATES AND CANADA. [Abstract.] Defining the Paleozoic period as has been done by Geikie in his Text-Book of Geology, it will include all the older sedimentary for- mations containing organic remains, up to the top of the Permian. Upon the paleontologic evidence it may be divided into an " older and newer division, the former (from the base of the Cambrian to the top of the Silurian system) distinguished more especially by the abundance of its graptolitic, trilobitic, and brachiopodous fauna, and by the absence of vertebrate remains ; the latter (from the top of the Silurian system to the top of the Permian system) by the number and variety of its fishes and amphibians, the disappearance of graptolites and trilobites, and the abundance of its cryptogamic terrestrial flora." The two divisions may be still further subdivided ; the upper into the Carboniferous and Devonian, the lower into the Silurian above and the Cambrian beneath. It is the Cambrian division we now have to consider. Stratigraphically it is difficult to fix any definite upper limit to the Cambrian system, owing to local causes having affected the con- ditions of sedimentation and consequent extinction or continuance of the fauna. Upon the evidence of the section in New York State on the western side of Lake Champlain, the Potsdam sandstone closes the period stratigraphically and paleontologically, the Calciferous formation forming little more than a closing deposit of the Potsdam and the large Chazy fauna appearing suddenly in the overlying lime- stone is entirely distinct from that of the Potsdam. In central GENERAL MEETING. 99 Nevada the section passes through limestones marked by the presence of a typical Potsdam fauna and on up to one that has the general facies of that of the Trenton Lower Silurian fauna. Midway of these passage beds occur layers of rock that carry representatives of both the Cambrian and Silurian faunas. Above this band the Cambrian fauna gradually disappears, and below it soon predomi- nates to the exclusion of the Silurian types. In this section we have an illustration of the gradual extinction of an older fauna as a new one is introduced, the sedimentation continuing and no physical dis- turbance occurring to change the conditions necessary for the pres- ence of animal life. It is the ideal section uniting the faunas of two periods, and if we had the blanks filled in between all the groups, as the blank between the Potsdam and Chazy in New York is filled in by the Nevada section, the Paleozoic would be a record of con- tinuous connected organic life from the base of the Cambrian to the summit of the Permian. It is convenient for stratigraphic geologic work to separate the Paleozoic series into subdivisions, and, as this is almost necessarily done on paleontologic evidence, I would separate the Cambrian as one characterized by what Barrande has named the first fauna.* Applying this to the Nevada section already mentioned, the line between the Cambrian and Silurian would be drawn where the types of the second fauna begin to predominate. With this defini- tion of the Cambrian system, the strata referred to it in the United States and Canada will be briefly noticed. In the Grand Canon of the Colorado the top of the Cambrian is the Tonto formation, a series of sandy calcareous strata 1,000 feet in thickness. The contained fauna is closely allied to that of the Potsdam sandstone and continues up to the summit of the forma- tion, the overlying Devonian rocks resting directly above strata containing Lingulepis, Iphidea, Conocephalites, Dlcellocephalus, etc. The Tonto rests uncomfortably on strata that were extensively eroded prior its deposition. This lower series comprises over 11,000 feet of unmetamorphosed shales, limestones, and sandstones, with 1,000 feet of interbedded lavas. It forms the Grand Canon and Chu-ar' groups of Powell and is characterized by the presence of a few fossils that enable us to refer it to the Cambrian but not to de- fine its stratigraphic horizon. That is done on the evidence of the position it occupies with reference to the Tonto. *The paleontologic evidence and discussion will appear in a future paper. 100 PHILOSOPHICAL SOCIETY OF WASHINGTON. The relations of the Grand Caiion section are snown in the first column of the page of sections. The Potsdam sandstone in Wisconsin occupies the same relative stratigraphic position as the Tonto formation, except that the break above the Tonto and between it and the Devonian is filled in by the Calciferous and other Silurian formations. As has already been said, the faunas of the Potsdam and Tonto are very much the same in general character. The Potsdam formation here overlies unconformably a series of strata that are directly comparable with the Grand Canon and Chu-ar' series. The Keweenawan series, according to Chamberlin, has about 10,000 feet of sedimentary strata distributed through 30,000 feet of eruptive rocks. In all this great mass no decisive evidence of organic life has been dis- covered, but knowing that the series is unconformably overlain by the Potsdam formation and that it in turn rests unconformably on the Archaean, as does the Grand Canon series, we feel justified in correlating the Grand Caiion and Wisconsin sections and they are uuited in the first column of the page of sections. The upper part of the Nevada section has already been men- tioned. Below the Potsdam horizon there occurs a distinct fauna, characterized by a considerable development of the trilobitic genus Olenellus, a genus that in the embryonic development of several of its species proves that it is derived from the Paradoxides family and is consequently of later date. This section is readily correlated with that of the Georgian group of Vermont, as there we have the Potsdam sandstone above the Olenellus horizon, and in the down- ward section both stop at nearly the same relative horizon. The position of the Georgian formation in Nevada and Vermont, in relation to the Potsdam, leads to the view that it represents a por- tion of the period of erosion between the Tonto formation and the Grand Caiion series and also the Potsdam formation and the Keweenawan series. The upper portion of the Tennessee Cambrian, the Knox shale, is correlated with the Potsdam sandstone, and so is the Knox sand- stone. The Chilhowee sandstone and Ocoee conglomerate and slates cannot be directly connected with the Georgian horizon, since the paleontologic data are insufficient. From their position beneath the Knox shale with its Potsdam fauna they are extended downward past the Georgian and into the Paradoxidian or St. Johns horizon. Their total thickness (Geology of Tennessee, pp. 158, 159) is nearly 15,000 feet. GENERAL MEETING. 101 O 5 ^ S 2. o o n > dd w o H o 2 102 PHILOSOPHICAL SOCIETY OF WASHINGTON. There is still another group, the St. Johns or Acadian, that occu- pies an horizon below the Georgian and may fill in a portion of the period of erosion between the pre-Potsdam and Keweenawan and the Tonto and Grand Canon series, or it may represent some of the upper portions of the Grand Canon and Keweenawan series. In the geologic sections it is placed beneath the Georgian and as above or passing down into the lower groups. For the present both it and the Paradoxidian argillites of Braintree must be left in doubt with regard to their relations to the lower Cambrian of Wisconsin and northern Arizona. Of the Canadian survey sections, the one on the north side of the Straits of Belle Isle is most interesting as it gives the Georgian horizon, but unfortunately an interval often miles in width is occu- pied by the straits before the section is again continued. In this interval the Potsdam group is lost, but farther along the coast there occurs, below limestones referred to the Calciferous horizon, a mass of sandstone that may be assigned to the Potsdam forma- tion — giving, in connection with the Olenellus or Georgian horizon, a section not unlike that of Central Nevada. No other section that has been determined in the British Provinces throws much light on the stratigraphic succession of the Cambrian rocks. At Point Levis a curious mingling of the Cambrian and Silurian faunas has been said to occur, but this is rather to be at- tributed to error in the interpretation of the stratigraphy in a much disturbed area than to a break in the sequence of organic remains, elsewhere so uniform. I prefer to accept the interpretation given by M. Jules Marcou, who says (The Taconic and Lower Silurian Pocks of Vermont and Canada, Proc. Bos. Soc. Nat. Hist., Vol. VIII, p. 252, 1862,) that the primordial or Cambrian types are associated together and occur in a belt of limestone that contains no traces of the second or Silurian fauna. The accompanying table of sections gives a general outline of the Cambrian. Numerous local sections of the Potsdam series are not mentioned, as they do not add materially to the general informa- tion in regard to the system in its vertical range. The geographic range is great, extending as it does from New- foundland to Montana on the northern line, and thence south to Nevada, Texas, and Alabama. GENERAL MEETING. 103 Mr. John Jay Knox made a communication on THE DISTRIBUTION OF THE SURPLUS MONEY OF THE UNITED STATES AMONG THE STATES. [Abstract.] President Jackson, in his message to Congress in 1829, referred to the difficulty in adjusting the tariff, so that the revenues of the Government should be but slightly in excess of its expenditures. He considered the appropriation of money for internal improve- ments, by Congress, as unconstitutional, but suggested that, if the anticipated surplus in the Treasury should be distributed among the States, according to their ratio of representation, such improve- ments could then be made by the States themselves. If necessary it would be expedient to propose to the States an amendment to the Constitution, authorizing such legislation. In his message for the following year he again suggested the same proposition. The receipts from sales of public lands for the three years, 1834, 1835, and 1836, were $44,492,381—slightly less than the total re- ceipts from this source for the thirty-eight years previous, from 1796 to 1834. On January 1, 1835, the country was virtually out of debt, and the receipts of the Government largely exceeded the previous estimates of the Secretary. The amount of surplus on January 1, 1835, was $8,892,858, and at the same date in 1836 $26,749,803. On January 1, 1837, it amounted to more than forty- two millions. In 1834-5-6, the public money, which had heretofore been de- posited in the Bank of the United States, was deposited in favorite State banks by order of General Jackson. The deposit of the revenues in these banks was followed by financial distress, and dur- ing the year 1834, and previous thereto, propositions were made in vhe public press for distribution of the surplus revenue among the States as a measure of relief. These propositions were first in the form of a distribution of the revenue from public land ; then a a distribution of the lands themselves ; and finally a distribution of the surplus. During the session of 1835, a select committee was appointed in the Senate, which reported a resolution to amend the Constitution so that the money remaining in the Treasury at the end of each year, until the first of January, 1843, should annually be distributed among the States and Territories. Both General 104 PHILOSOPHICAL SOCIETY OP WASHINGTON. Jackson and Secretary Woodbury were opposed to this proposition, as the withdrawal of public moneys would deprive the State banks of the deposits, and would be likely to increase the financial troubles. A bill to distribute the surplus was, however, introduced in the- Senate, and passed by a vote of 25 to 20. It was evident that this bill could not pass the House, as a majority of its members con- sidered the bill, in the form of a distribution, as unconstitutional. The friends of the measure in the Senate determined to change its form so as to remove the difficulty. A bill then pending in the Senate was so amended as to change the proposition for distribu- tion to a proposition for deposit with the States, and in this form it passed the Senate, and subsequently the House by a large majority, 155 to 38. This act of June 23, 1836, provided for the deposit with the treasurers of the several States of 37 millions ($37,468,859) in four instalments during the year 1837—the Secretary of the Treasury to receive certificates of deposit therefor signed by competent au- thority, in such form as he should prescribe, which certificates should express the usual legal obligation, and pledge the faith of the State for the safe keeping and repayment of the deposit, from time to time, whenever the same should be required. The first three installments were deposited. Before the last installment, payable on the 1st day of October, was transferred, a series of financial dis- asters culminated in the crisis of 1837, and there was no surplus to deposit. Further legislation was deemed necessary in this emer- gency, and an extra session of Congress was called by President Van Buren. During this session, on September 11, 1837, a bill was reported from the Finance Committee of the Senate, providing that the transfer of the fourth installment should be indefinitely post- poned. The opposition to this bill was persistent, and there was a long debate, which was participated in by "Webster, Clay, Calhoun, Buchanan, Benton, Silas Wright, Caleb Cushing, and others of the Senate; and in the House by Adams, Fillmore and Sibley of New York, Bell of Tennessee, Wise of Virginia, and many others. A bill was finally passed, providing for the postponement of the deposit of the fourth installment until January 1, 1839. It passed the House by a vote of 119 to 117, and contained an amendment proposed by Mr. Buchanan, providing that the deposits should not be subject to the requisition of the Secretary of the Treasury, but should remain until called for by Congress. On the 1st of Jan- GENERAL MEETING. 105 uary, 1839, there were no funds in the Treasury available for the payment of the fourth installment, and since that date there has never been a surplus in the Treasury above the debts and estimated expenditures of the Government. The amount of the three installments was $28,101,645, and the amount placed in the Treasury of each State has since been carried among " unavailable funds of the general Treasury," as may be seen by reference to the annual reports of the Treasurer of the United States. The fourth installment, amounting to $9,367,215, has never been transferred or deposited, and recently the State of Virginia, through the action of its Legislature, and the State of Arkansas, through the action of its treasurer and one of its United States Senators, has applied to the Secretary of the Treasury for the payment of this last instalment. It is generally believed that the moneys deposited by the Gov- ernment with the different States were, for the most part, wasted or employed in works of internal improvement which were unneces- sary. The data for a full investigation of this subject are not at hand, but it is known that the States of Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, North Carolina, Illinois, Indiana, Kentucky, Ohio, and Missouri appro- priated a considerable portion of the income from this fund to the support of public schools ; and that in many of these States the income from the whole fund has been from the commencement, and still is, devoted to the education of the people. A bill was introduced by Senator Logan, during the first session of the last Congress, providing that the entire income derived from the internal-revenue tax on the manufacture and sale of distilled spirits shall be appropriated and expended for the education of all children living in the United States, as shown by the census of 1880 and each succeeding census. The bill also provides that the States shall be required, before receiving the benefits of the act, to make school attendance obligatory upon all children between the ages of seven and twelve years, for at least six months in each year. Mr. Alvord inquired as to the present status of the Smithsonian fund, amounting to about half a million of dollars, which was in- vested in the bonds of the State of Arkansas. Mr. Knox said that the Government has assumed the Arkansas 11 106 PHILOSOPHICAL SOCIETY OF WASHINGTON. bonds formerly held by the Smithsonian Institution, and that the Government also held quite a large amount of the bonds of the States of Virginia and Arkansas in the Indian Trust Fund. If legislation should be obtained authorizing the payment of the fourth nstalmeut to these States, such legislation should provide that the payment be made in the bonds now held by the Government. Mr. Alvord said that the history of agricultural college grants was not thus far very encouraging. It would have been better if Congress had provided that the agricultural colleges should never be united with other colleges. The union was apt to lead to con- fusion and controversies, and lower the standard and prestige of both. Witness the case of Dartmouth College. In this reference Mr. Mussey concurred. The Hon. Hugh McCullough, being invited by the Chair to participate in the discussion, said that in Indiana the application of the money deposited by the United States had occasioned a long de- bate, which had resulted in its division. One half, by means of a system of commissioners, was loaned to individuals on land and mortgage ; the other half was put into stock of the State Bank, with which the speaker was at that time connected. In a financial crisis the first half was practically lost, probably less than one- twentieth part being recovered ; but the loss was fortunately made good by the bank stock, upou which dividends were regularly paid, and by which the investment was eventually doubled. Since the closing of the bank, this money has constituted the school fund of Indiana. Mr. R. D. Cutts made a communication on THE ACTION OF THE INTERNATIONAL GEODETIC ASSOCIATION AS TO AN INITIAL MERIDIAN AND UNIVERSAL TIME. [Abstract.] The International Geodetic Association of Europe, formed for the purpose of connecting the systems of triangulation executed by the different States of Europe, and hence for the measurement of arcs, and for the discussion of all questions of science comprised within the term Geodesy, has been in active existence for many years. The meeting in 1882 was held at The Hague, and before adjournment it was decided that the seventh conference should meet at Rome, in October, 1883. GENERAL MEETING. 107 Iii the meantime, all governments in diplomatic relations with the United States were invited by the President, in accordance with the act of Congress, August 3, 1883, to send delegates to Washing- ton for the purpose of fixing upon a meridian proper to be em- ployed as a common zero of longitude and standard of time, reck- oning throughout the globe. More than twenty of these countries had signified, before October last, their acceptance of the invitation, but these did not include many of the principal governments of Europe. The delay in forwarding their definitive replies was due to their desire to have the advice, before committing themselves, of the Eurpean Geodetic Association. Hence it was at the request of many of these governments that the Association took up the subject of the unification of longitudes, and of the introduction of a uni- versal time. So soon as it was decided to take such action, General Ibanez, of Spain, the then President of the Association, addressed a letter to the Superintendent of the Coast and Geodetic Survey, urging him in strong terms to send a delegate to the meeting at Rome. So short a notice was given, however, that the delegate selected had to start at once, reaching Rome only on the morning of the first day's ses- sion, October 15th. After a full discussion of the different views presented, the fol- lowing resolutions were almost unanimously passed on October 24th. It must be borne in mind that they are merely of an advisory character, sanctioned and urged, nevertheless, by the highest scien- tific authority. It is the function of the convention to be held at Washington next year to take official and decisive action on the subject in all its details. Resolutions of the International Geodetic Commission in relation to the Unification of Longitudes and of Time. The seventh general conference of the International Geodetic Asso- ciation, held at Rome, and at which representatives of Great Britain, together with the directors of the principal astronomical and nau- tical almanacs, and a delegate from the Coast and Geodetic Survey of the United States, have taken part, after having deliberated upon the unification of longitude by the adoption of a single initial meridian, and upon the unification of time by the adoption of a universal hour, have agreed upon the following resolutions : 108 PHILOSOPHICAL SOCIETY OF WASHINGTON. I. The unification of longitude and of time is desirable, as much in the interest of science as in that of navigation, of commerce, and of international communication. The scientific and practical utility of this reform far outweighs the sacrifice of labor and the difficulties of adaptation which it would entail. It should, there- fore, be recommended to the Governments of all the States in- terested, to be organized and confirmed by an International Conven- tion, to the end that hereafter one and the same system of longitudes shall be employed in all the institutes and geodetic bureaus, for the general geographic and hydrographic charts, as well as in the astronomical and nautical almanacs, with the exception of those made to preserve a local meridian, as, for instance, the almanacs for transits, or those which are needed to indicate the local time, such as the establishment of the port, &c. II. Notwithstanding the great advantages which the general in- troduction of the decimal division of a quarter of the circle in the expressions of the geographical and geodetic co-ordinates, and in the corresponding time expressions, is destined to realize for the sciences aud their applications, it is proper, through considerations eminently practical, to pass it by in considering the great measure of unification proposed in the first resolution. However, with a view to satisfying, at the same time, very serious scientific considerations, the Conference recommends, on this occa- sion, the extension by the multiplication and perfection of the nec- essary tables, of the application of the decimal division of the quad- rant, at least, for the great operations of numerical calculations, for which it presents incontestable advantages, even if it is wished to preserve the old sexagesimal division for observations, for charts, navigation, &c. III. The Conference proposes to the Governments to select for the initial meridian that of Greenwich, defined by a point midway be- tween the two pillars of the meridian instrument of the Observa- tory of Greenwich, for the reason that that meridian fulfils, as a point of departure for longitudes, all the conditions demanded by science ; and because being at present the best known of all, it presents the greatest probability of being generally accepted. IV. It is advisable to count all longitudes, starting from the meridian of Greenwich, in the direction from west to east only. V. The Conference recognizes for certain scientific wants and for the internal service in the chief administrations of routes of com- GENERAL MEETING. 109 munication, such as the railroads, steamship lines, telegraphic and post routes, the utility of adopting a universal time, along with local or national time, which will necessarily continue to be em- ployed in civil life. VI. The Conference recommends, as the point of departure of universal time and of cosmopolitan date, the mean noon of Green- wich which coincides with the instant of midnight, or with the commencement of the civil day, under the meridian situated 12 hours or 180 degrees from Greenwich. It is agreed to count the universal time from h to 24h . VII. It is desirable that the States which, for the purpose of adopting the unification of longitudes and of time, find it necessary to change their meridians, should introduce the new system of lon- gitudes and of hours as soon as possible. It is equally advisable that the new system should be introduced without delay in teaching. VIII. The Conference hopes that if the entire world should agree upon the unification of longitudes and of time by accepting the meridian of Greenwich as the point of departure, Great Britian will find in this fact an additional motive to make, on its part, a new step in favor of the unification of weights and measures, by acceding to the Convention du Mitre of the 20th May, 1875. IX. These resolutions will be brought to the knowledge of the Governments and recommended to their favorable consideration, with the expression of a hope that an International Convention, confirming the unification of longitudes and of time, shall be concluded as soon as possible, by means of a special conference, such as the Government of the United States has proposed. Mr. Hilgard said that while the report of the Association did not conform in some of its details to the desires and interests of this country, nevertheless our principal object had been gained by the endorsement of the Association for the International Conference on the subject of standard time, to be held in Washington. The selection of the meridian of Greenwich as the starting point for longitudes, was more convenient for us than for Europeans ; Europeans alone are liable to the confusion arising from the numerical identity of meridians east and west of Greenwich. It will be impossible, however, for us to agree to the rule which counts all longitudes from west to east. 110 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. Elliott opposed the establishment of noon as the initial hour of the clay. It seemed to be proposed in the interest of astron- omers, who work at night, and would not be submitted to by the people at large. He exhibited a map showing a grouping of the railroads of the country under the recently adopted time schedule. Mr. Cutts said that the resolutions of the Geodetic Association do not appertain to civil time. The " universal time " they advo- cate is for the use only of astronomers and great transportation corporations. Other remarks were made by Mr. Newcomb. 242d Meeting. December 8, 1883. By permission of the Secretary of the Smithsonian Institution, the Society occupied for the evening the Lecture Hall of the National Museum. The President called Vice-President Mallery to the Chair. There were present about three hundred members and guests. By invitation, the Presidents of the Biological and Anthropo- logical Societies occupied seats on the platform. The President of the Society, Mr. J. W. Powell, delivered the annual address, taking for his subject THE THREE METHODS OF EVOLUTION. [The address is printed on pages xxvh-lh, ante.~] The Chair invited the members of the Society and their friends to remain for a period after adjournment, for the purpose of social intercourse. The Society then adjourned. GENERAL MEETING. Ill 243d meeting. December 22, 1883. the thirteenth annual meeting. The President in the chair. Thirty-four members present. The minutes of the 226th, 241st, and 242d meetings were read. The Chair announced the death, since the last meeting, of General R. L). Cutts. The Chair announced the election to membership of Messrs. Robert Simpson Woodward, Daniel Elmer Salmon, and John Mills Browne. The Secretary's report on the membership of the Society was read. During the year the Society received seventeen new mem- bers, lost eight by death, and lost three by resignation. The Treasurer not being present, the Chair appointed Mr. Henry Farquhar Treasurer pro tempore. The officers for the ensuing year were then elected by ballot. (The list is printed on page XV.) On motion of Mr. Jenkins, the vote for President was made unanimous. The Chair appointed Messrs. C. A. White, S. Newcomb, and H. C. Yarrow a committee to audit the annual report of the Treasurer. The Society then adjourned. BULLETIN OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON, MATHEMATICAL SECTION. "3 STANDING RULES OF THE MATHEMATICAL SECTION. Adopted March 24, 1883. 1. The object of this Section is the consideration and discussion of papers relating to pure or applied mathematics. 2. The special officers of the Section shall be a Chairman and a Secretary, who shall be elected at the first meeting of the Section in each year, and discharge the duties usually attaching to those offices. 3. To bring a paper regularly before the Section it must be sub- mitted to the Standing Committee on Communications for the stated meetings of the Society, with the statement that it is for the Mathematical Section. 4. Meetings shall be called by the Standing Committee on Com- munications whenever the extent or importance of the papers sub- mitted and approved appear to justify it. 5. All members of the Philosophical Society who wish to do so may take part in the meetings of this Section. 6. To every member who shall have notified the Secretary of the General Committee of his desire to receive them, announcements of the meetings of the Section shall be sent by mail. 7. The Section shall have power to adopt such rules of pro- cedure as it may find expedient. 115 LIST OF MEMBERS WHO RECEIVE ANNOUNCEMENT OF MEETINGS OF THE MATHEMATICAL SECTION. Abbe, C. Alvord, B. Avery, R. S. Babcock, O. E. Baker, M. Bates, H. H. Billings, J. S. Burgess, E. S. Christie, A. S. Coffin, J. H. C. DeLand, T. L. Doolittle, M. H. Eastman, J. R. Elliott, E. B. Farquhar, H. Flint, A. S. Gilbert, G. K. Newcomb, S. Gore, J. H. Green, B. R. Hall, A. Harkness, W. Hazen, H. A. HlLGARD, J. E. Hill, G. W. King, A. F. A. KUMMELL, C. H. Lefavour, E. B. Peirce, C. S. Ritter, W. F. M'K. Smiley, C. W. Taylor, W. B. Upton, W. W. Walling, H. F. Winlock, W. C. 116 INAUGURAL ADDRESS OF THE CHAIRMAN OF THE MATHEMATICAL SECTION, By Asaph Hall. Gentlemen of the Mathematical Section: I thank you for the honor you have conferred on me by my election as Chairman of this Section, and the best return that I can make is to do my utmost to render our meetings as interesting and successful as possible. Although my duties have been such that I have not been able to take a very active part in the proceedings of the Philosophical So- ciety, it is easy to understand how a need has been felt for a more full and frequent discussion of mathematical questions. Mathe- matics has indeed been called the queen of the sciences, but the rigor and dryness of its methods make it distasteful to many. The fact seems to be that as any branch of knowledge advances and finally is reduced to law, it loses in a large degree its attractive- ness and popularity. Then, it is only with the indefinite outlines and the obscure boundaries of this science that most people like to deal ; and this may be natural and right, since nearly all advance- ment originates in speculation and doubt, which lead to investiga- tion, and which, by a variety of motives, spur men on to labor. But the science of mathematics, though old, is yet young and vigo- rous. We have now six journals of the highest rank, which are devoted almost exclusively to pure mathematics—two in Germany, two in France, one in England, and, I am glad to say, one in our own country. These journals are devoted to the discussion of the highest conceptions of space and number, treating chiefly of the laws and forms of analytical expressions, and generally they touch lightly on any practical application of the science. Such discus- sions prepare the way, however, for better and more general prac- tical methods, and in our own country they have, I think, another value. For one, I can hardly accept the doctrine, advocated in some quarters, that the American scientific man of the future should 117 118 PHILOSOPHICAL SOCIETY OF WASHINGTON. be distinguished by his facility in getting a patent on his discovery, in forming joint stock companies and watering stock, and in sud- denly becoming rich at the expense of his fellow-men. Such a career may be a natural result of our present system of sociology, but it does not seem to be in harmony with scientific thought and research, and our social need is for men of a different character. Far nobler is the life of one who devotes himself to the study of the most abstract forms of science ; winning for us, if haply he may, another forward step up the hill of knowledge. But when we come to the field of applied mathematics we soon learn how necessary are the studies of the pure mathematician. Nearly all the researches in natural philosophy, where the action of forces is concerned, require the formation and solution of differen- tial equations, and hence the theory of such equations becomes important, and in some cases almost essential, for the advancement of physical investigations. It is not, of course, to be supposed that experiment and observation are to be done away with or neglected, or that mere skill in differentiating, integrating, and solving equa- tions can supply the place of correct thinking. In fact, we may be sure that Leibnitz was mistaken when he declared that the inven- tion of the differential calculus had made known that royal road to knowledge for which the king had inquired in vain of Euclid. But still it remains true that this calculus forms the most powerful engine we have for the solution of questions in natural philosophy. It enables us to adopt the old maxim, " divide et i?npera." If we can reduce the problem to its elements, and can form its true differ- ential equation, the rest of the work is purely mathematical. Un- fortunately, the differential equations that occur in the problems of nature are very different from those given in our text-books, and their exact solution is in most cases impossible. Here we must rely chiefly on that happy device of the variation of constants, by means of which the solution of simpler forms is extended to the more complex. One of the great advantages of putting a question in a mathemati- cal form is the precision with which it can be stated. If we are right, the truth of our assertion will be the sooner acknowledged, and if we are wrong, our error can be the more easily detected. Fre- quently it has seemed to me that disputes would be avoided in the meetings of our scientific societies if men would take the trouble to put their assertion into a formula and write it on the blackboard ; MATHEMATICAL SECTION. 119 and certainly there would be a clearness and meaning that are so often wanting. Thus, if any one asserts that when a planet comes to its perihelion it ought to fall into the sun, the law of gravitation being true, he is not worth listening to unless he will put his asser- tion into a formula ; and when he is able to do this he will probably find out his own error. There will be so much gain by simply re- ducing the problem to its elements and giving it a correct form. Again, where scientific statements may be true, there will be a gain in giviug them, when possible, a mathematical expression. Thus, when we are told that the fixed star 1830 Groombridge is running away, disobedient to the law of gravitation, how much better it would be if we could see on the blackboard the mathematical proof of this assertion, so that we could judge for ourselves on what assumption it is based. The subject of impulsive forces is one that we hear disputes about in our own society, and it seems to be a fair field for a mathematical exposition. How often do we see such phrases as " energy," " potential energy," " kinetic energy," " con- servation of energy," " work," " virial," &c. Could not some one of our members give us a clear account of these terms, show us how they are connected with the general equations of mechanics, what new ideas they contain, and on what limitations they may be based ? As the application of mathematics is extended, sounding phrases are sure to come into use, and it is well to test them and know what they mean. In the discussions of this Section, while all are invited to be critical, I trust that we shall all be kind and good tempered. We come together for discussion and mutual improvement, and while error is not to be spared we must be charitable to each other's faults. BULLETIN MATHEMATICAL SECTION, A communication signed by Mr. J. E. Hilgard and nineteen other members of the Philosophical Society, asking that a Section in Mathematical Science be formed, as provided in Paragraph 6 of the Standing Rules of the Society, was presented to the General Committee at its regular meeting January 27, 1883. The propo- sition was agreed to, and Mr. Hilgard was empowered to call a special meeting for the purpose of organizing such a section ; the call being extended to all members of the Society. 1st Preliminary Meeting. February 17, 1883. Twelve members met in the library of the Army Medical Mu- seum, in answer to the first call. Mr. Hilgard not being present, Mr. E. B. Elliott was called to the Chair. An informal discussion followed, which brought out a unanimous sentiment in favor of forming the Section. With some differences of opinion as to details, it was agreed to postpone formal action, and the meeting adjourned subject to call. 2d Preliminary Meeting. March 5, 1883. Mr. Hilgard in the Chair. Fifteen members present. A plan of organization was adopted, and referred to the Gene- ral Committee of the Society for consideration. 12 121 122" PHILOSOPHICAL SOCIETY OF WASHINGTON. 1st Regular Meeting. ' March 29, 1883. Fourteen members present. In the absence of Mr. Hilgard, who had presided over the meeting for organization, Mr. G. W. Hill was called to the Chair. The standing rules for the government of the Section, as adopted at the last meeting of the General Committee of the Society, were read. The Section then proceeded to elect officers for the year 1883. On motion of Mr. Winlock the rules of the Society at its An- nual Meeting were followed. Mr. Asaph Hall was chosen Chairman and Mr. H. Farquhar Secretary. A letter from Mr. Marcus Baker, dated Los Angeles, Cal., was read by Mr. Christie. It expressed a strong interest in the Sec- tion, recommending that it should be conducted as nearly as possi- ble on the plan devised by the late Prof. Henry for the Society itself, by which business and science are kept apart. A free use of pencil and paper at the meetings, and seats around a table, were further suggested. The letter closed by advocating the foundation of a new mathematical journal. Mr. Christie then made a communication on A QUASI GENERAL DIFFERENTIATION. The paper was discussed by Messrs. Kummell, Elliott, Hill, and Doolittle. The author reserves it from publication to await further research. A resolution was passed, requesting the committee in charge of the matter to call meetings of the Section on Wednesday evenings. 2d Meeting. April 11, 1883. The Chairman, Mr. Hall, presided. Present, ten members and two invited guests. It was announced that the Editor of " Science " would publish brief reports of the meetings of the Section. MATHEMATICAL SECTION. 123 The Chairman read an inaugural address, [given in full on pp. 117 to 119 ante.] Mr. C. H. Kummell then began a paper on ALIGNMENT CURVES, which was not finished at the time of adjournment. 3d Meeting. April 26, 1883. The Chairman presided. Present, sixteen members and one invited guest. Mr. Kummell completed his paper, begun at the second meet- ing, on ALIGNMENT CURVES ON ANY SURFACE, WITH SPECIAL APPLICATION TO THE ELLIPSOID. [Abstract.] The attempt to put a number of points in line on a curved sur- face whose normals are supposed to be given (abstraction is made of deviations of the plumb-line and lateral refraction) gives rise to various curves, which I call alignment curves. There are two classes—alignment curves with two given termini and those with a starting point only. There are three distinct curves of the first class, viz. : 1. The normal section, if the surveyor directs his assist- ant to place staffs in line from one end of the line. 2. A curve described if the surveyor would align a point near him, then move up to this point, thence align another point, etc., until the terminus is reached. This process is that used in chaining, or more roughly by a pedestrian going towards a point, and is characterized by requiring only foresights. I call it proorthode (xpo, 6p0u$, 6do?)* 3. A curve resulting if a backsight is also taken. This curve is therefore defined by the condition that the normal plane at any point of it which passes through one end also passes through the other. I call it diorthode {did, 6p0d$, 636$), because it may be con- * This and other names of curves were coined by my friend, Mr. Wm. R. Gait, of Norfolk, Va. 124' PHILOSOPHICAL SOCIETY OF WASHINGTON. sidered straight all through at any of its points. This curve may be considered the ideal curve of a primary base line. Various names have been given to it when on the terrestrial spheroid. Dr. Bremiker, who appears to have first considered it (in his Studien ueber hoehere Geodsesie, 1869), proposed the name " Feldlinie" ; that is, field line. He thinks it should be adopted as the geodetic line, because both linear and angular measurements conform to it. Clarke, Zacharise, and Helmert have also mentioned it, the latter, however, only in a note, where he remarks that it deserves no con- sideration in geodesy. To the second class belong two curves : 1. A curve described as follows: The surveyor at the starting point takes his directions from a staff at short distance and directs his assistant to place a staff in the prolongation. Repeating this operation from the first staff, from the second staff, etc., he describes a curve which is well known to be the shortest curve between any of its points. It is usually called the geodetic line. However, since this name would apply at least equally well to the three curves already con- sidered, I propose the name brachisthode (fipd^t®-<^&]D^©-(*-'>®] -[<^®-<<-'>(g)][<^®^-<>(*)] = [Cy8 — V) ($ — X) — {x2 — x)(rj— y)-] (^£j + to -•)(*-*)- (ft -3D (C- *)](^) + [(^ _ x) (c - .) - fc - .) (? - *)] (^) (3) If in this we replace the surface point (x, y, z) by the surface point (xv yv zx) and (?, ^, CJ by the surface point (re, y, z) we obtain : = [(&— ^) (« - »,) — 0»8— a,) (g/- &)]^J + [(^2— *Q 0/ - !/i) — (2/2 — Vx) (« — 2i)J (^) + EO-2-*!) (-*)-(v-«0 (*-«i)](^) (4) which, if combined with the equation of the surface, gives the nor- mal section at (xv ylt zx) through (x2 , y2 , z2). If, however, we replace in (3) ((SO -<*-)(sH* By means of the equation of the surface (1) and its differential equation any one of the variables with its differential can be eliminated. The resulting differential equation being integrated so as to contain the starting point (x Y , yv zx ), will be the equation of a projection of the proorthode on a coordinate plane. The proorthode being differently related to its ends, will be dif- ferent forward and backward, while the diorthode is the same for- ward and backward. MATHEMATICAL SECTION. 127 The following diagram will illustrate the relative course of these curves : normal section diorthode prodrthode brachisthode Any surface of the second degree may be represented by w=0 \ a J ^ p ^ q (8) The origin is taken at one of its real vertices, so that (a, 0, 0) is its centre. The equation of the diorthode is then by (5), if we write x2 — x 1 = A.r; y2 — yt = by ; z2 — z1 = A z, = [(&- V) Oft - *) - Oft- «) (2/i - 2/)] Y + [(ft - 2) (y, — y) — (fc— !/) (ft - 2)] — ^~ + r>3 - *) (ft - ^) - (ft ~ s) Oft - *)] J = (ft (or a = q or p = q), it has its center at an infinite distance, and it is a parabolic hyperbo- loid. In this case the base surface becomes : fe=£±J?+i_. (U) a ' q y which is a surface of revolution of the second degree. If a=^)= q, then (9) becomes a plane and the base surface a sphere. (9) is evidently satisfied by the center (a, 0, 0), therefore the intersecting surface always passes through the center of the base surface. I consider now the ellipsoid : = J + F+7-! <12> We have then the intersecting surface of the diorthode : x v o = Oss/i— «i % + z*y— v* z) tf + (X zi— xv z-i + x*z —•***) p- + (2/2 xi —yr x-i+ y*x — xAy) ~# 0- 3) Let (0, yx , 3X) be the point where the chord (1, 1) pierces the yz - plane Oy,0,zy) " " " '« " ex- " (x z,yz,0) " " " " - xy - then we can easily verify the relations : X2 Vl Xl Vi . _ X2 g l ^'l g2 Q^ \ (14v) (14.) #x — Aa; MATHEMATICAL SECTION. 129 (13) will take either of the following equivalent forms : = Az (y, - «bY) J + Ax (zx - fic2z) -jjr + Ay (xy - r»^f (131) = Ay y - «» Jr + a3 O, - /3>)|- + a* (yx - rb2y)£ (1311) The following relations will be much referred to : _ &. . 5l _ £ _. 5- _£ + & n 6)Ay T A3 A3 ~ AX Ax ~ Ay K J Xy— y* y. 2 v y, — v, zx xz x? Vx zj — z, yz zz *z — *, ** ~ *z~yx — yz J = Xy \k 3x + V* Zs Xz (18) Replacing in these Ax, Ay, Az ; yx , g , xz ; 3X , ay , yz hy ^->¥>1? '><> l3 *> r* > <> l3*> r» (19) wehave:0=^ + §;=5+^=^ + ^ (16'; z 9 . 2 — r* k /? 2 . rf— «ba «c2 ra2 /V V /V — <2 ' rb2 ~"/? 2 ~ra2 -/*a «.* - £' A2 (17 1)a c ra ' ^16 ) aud (161) 130 PHILOSOPHICAL SOCIETY OF WASHINGTON. Substituting the value of y from the first into the second equation we have : = ^x rb 2 y* * , (x 7 - x z) x + (^ - *) QjJ - a) by (17,) and (17/; ^ 2 -r, 2 /_^y ,%z\ , * Corresponding to the first value we have /a /a 'a » ~?7*"~?7 — k— -*• hy (17i) and corresponding to the second : Denoting these constants by # c , a;b , yo, ya , respectively, we have then the equations of a pair of generatrices of the hyperboloid (13) perpendicular to the xy - plane : x= 2^=xc ; y = fi=y (20,)/a I b Similarly the pair of generatrices perpendicular to the 3/2 - plane: 2/= jh= y, ; - z f: =^ (20, 1 ) and that perpendicular to the zx • plane : Z X z= fi = z* ; * = f2 = xb (20y) 2 = ^ = z * > x = 7* = * (20, 1 ) o 'a Now the second line of each pair intersects the chord, as may be proved thus: The equations of the chord (1, 2) are any two of the following three equations : £-+£_! = (21.)X -Ty x ^ MATHEMATICAL SECTION. 131 —+——1 = (21) f +^_l = (21,) Now ^+¥~ 1=sh+h~ x = < + ^2 - + 2 V* ZJ> 0*b> V*> ZJ> (x c , ya , za) form a warped hexagon, which lies wholly in the hyper- boloid, and its sides may be considered six intersecting edges of a characteristic parallelopipedon. These edges ai*e : ^ = y©* •-">/*+ * (22) This formula, although laborious for practical use, is the most rigorous measure of skill in shooting, and there is no need of other formulae except when shots are lost. In that case it requires an important modification, whereby it loses in rigor if the number of lost shots is considerable. Assuming the precisions of sighting and leveling equal, then the reduced distance r in (12) will be the actual distance s of a shot ; and if the target is circular, of limiting radius R, we have _& / _ R2\ ) = n 1 - R2e & + 2e 2 ( 1 - e * ] I Now by (13) nR =sn ( 1~ e 2E* J n therefore ry^ R=%lR ?-U - nAx* n and ^ M *+(*-**)" (23) This formula reverts, of course, to (22), if n = n and it makes the most probable sum of the squares of the lost shots [S2f = Jl(n - n \& and since ( n ~~ n r ) R2 is tne smallest possible actual value of this quantity ; this expression for it is quite plausible. The targets used by the National Rifle Association are rectan- gular. (At long range they are 12 feet wide and 6 feet high). MATHEMATICAL SECTION. 143 Let a (= 6 feet) be the limiting value of x and b (= 3 feet) that for y, then we have, if nab is the number of hitting shots b y * / r/r —— - 9 f —p -^-=. e 2V = -7= rff e > and a o similarly Pfb , is tabulated in Chauvenet's Method of Least Squares (Table IX, appendix, to the argument t), and is therefore known.* "We have further : x2 b 1*]**-% C tfJ^ e 2e"T -J3U 1 J ' £x\/2TT J ^yV217 — a —b 2e 2 e y -*\-[£i' "^ + *f el/ 2,r J J £*\/ 2n — a — a J = nex si\(P*8 -*aP'0 (25x) c/p^ 2 — a Here P^ a denotes ,, a = -7=-= e and can also be taken from Chauvenet's table, being 100 X difference. Similarly, ryf* = nt *Pt& {PK _ kFk) (25y) By virtue of (24) we have also [> 2 ] % ab i — -m ^ nAl — Kpt) V = -T m (25/) and these formulae may be used to compute sx and ey by an obvious approximative process. They show that ex 2 > L Jl ' as it should 144 PHILOSOPHICAL SOCIETY OF WASHINGTON. be ; but it may, or rather must, happen sometimes that the most n n probable increase of the sum of x2 and tf or [re2] + [y2] consistent W ab _ _ «.b with (25') is < (n — wab ) b2,b being the smaller limit. Such a re- sult cannot be accepted, being contradictory to the fact that there are n — ?iab shots at a greater distance than b. The following method gives plausible results in that case. Assume 0/) = n (6 being real for all values of h, both positive and negative, was to be interpreted for /i<^0 or Ii^>2R as the vol- ume of the segment of the equilateral hyperboloid of two sheets whose axes equal R; this volume being taken with a negative sign. It was positive for negative values of h, since it must become zero when h = by negative increments ; hence the minimum of the function when A = in such problems as the one discussed. Mr. Doolittle read a communication on THE REJECTION OF DOUBTFUL OBSERVATIONS. [Abstract.] For the purposes of this discussion we may divide errors into MATHEMATICAL SECTION. 153 two 'grand classes, and name them, from their consequences, instruc- tive errors and uninstructive errors. The latter class includes blun- ders in recording, pointing on wrong objects, &c. The former con- sists of errors that indicate error in other observations. I once tried the experiment of dropping a short straight piece of wire five hundred times upon a sheet of ruled paper and counting the number of intersections of the wire with a ruled line. When the end of the wire touched or nearly touched a line, and inter- section was doubtful, I counted it as half an intersection. I re- corded the number of intersections in groups of fifty trials, as fol- lows : 23, 26, 28.5, 24, 31.5, 28, 27, 14, 25, 28.5. These numbers may be regarded as observations from which may be deduced the probable ratio of the length of the wire to the distance between two consecutive lines ; and it seems impossible to account for the remarkable smallness of the eighth number by any supposition of uninstructive error. It is almost certain that a ratio deduced from it alone is largely in error ; but it indicates that the other nine observations are somewhat in error, and that its error is needed to counterbalance theirs. If we retain it, and regard the mean of all as the most probable truth, we infer that this observation is 11.55 units in error. If we reject it, and take the mean of the other nine as the most probable truth, we infer that this observation is 12 5-6 units in error. It should be remembered that the rejection of an observation does not sweep from existence the fact of its occurrence; but merely increases its already large estimate of error. Because an error of 11.55 units is so large as to be very improbable, shall we therefore infer that an error of 12 5-6 units is more probable? It seems very clear to me that the larger an instructive error is the more instructive it is, and the more important is it that the observation containing it should not be rejected. The mean of all the ten above-described observations being regarded as the most probable truth, any one of the other nine could be better spared than the eighth. On the other hand, the larger an uninstructive error is, the more important it is that the observation should be rejected. Whenever an observation is intelligently rejected, there is a comparison of two antecedent probabilities, viz. : that of the occurrence of an instructive error of the magnitude involved and that of the occurrence of an uninstructive error of the same mag- nitude. When an error is evidently so large that it cannot possibly belong to the instructive class, the antecedent probability of such 14 154 PHILOSOPHICAL SOCIETY OF WASHINGTON. an instructive error is ; the antecedent probability of an unin- structive error is always greater than ; and the observation should certainly be rejected. But since the theory of least squares allows no limit whatever to the possible magnitude of instructive errors, such rejection involves the admission that the method of least squares is not applicable to the case. When an observation involves a merely suspicious error, which is neither so large that iustructive- ness is impossible nor so small as to pass without question, it would seem reasonable that the observation should be weighted according to the relative magnitudes of the two antecedent probabilities which I have mentioned ; but this can never be determined with any approach to mathematical precision. In order to make this matter clear, let us suppose for example that ninety-nine observations of equal weight and known to be free from uninstructive error are separately written on as many cards ; that the number 25 is arbitrarily written on a similar card ; that these hundred cards are thoroughly shuffled ; and that ten cards being then drawn at random, the following numbers appear on them : 15, 18, 14, 25, 17, 16, 15, 18, 16, 17. Let it be required to determine from these data, according to the theory of least squares, the probability that the number 25 on the fourth card drawn is the record of an observation. Here the antecedent probability of an uninstructive error is by hypothesis equal to 1-10. I commence by assuming a value of the required probability, and weight the doubtful observation accordingly. I then proceed in the ordinary method and determine an approximation to the antecedent probability of the occurrence of a genuine observation giving the value 25 by integrating —— j e dt between the limits corresponding to 24.5 and 25.5, since the observations are taken to the nearest unit. This integral is the antecedent proba- bility of an instructive error of the given magnitude, tainted with the incorrectness of the assumption with which I began. Call this integral -p. Then , is the resulting required probability. If it agrees with my original assumption, the problem is solved. If it does not agree, I have data for a better assumption according to the well-known method of trial and error. After a few repetitions of the process, as I have found by experiment, an assumption can be made that will be verified by agreement with the result. MATHEMATICAL SECTION. 155 In practical problems the antecedent probability of blunders and other uninstructive errors is never known, and is only matter of exceedingly vague conjecture. Perhaps if a very large number of observations were examined, and the proportion of evidently unin- structive errors ascertained, a somewhat intelligent estimate might be made of the proportion of those that exist but are not evident ; and data of some little value might be gathered toward a scientific method of weighting. But I have no faith that the result would be any where near worth the labor. At present, the best that a computer can do is to reject entirely, or retain entirely, or assign a simple weight, such as h, i, or I, in sheer desperation, and with the feeling that his judgment is nearly or quite worthless. It would be utter folly to assign weights upon a centesimal scale ; and it would also be utter folly to conjecture au antecedent probability and proceed accordiug to the method just set forth. It is well known that the method of least squares gives very un- trustworthy information in regard to the antecedent probability of large instructive errors. In regard to the other antecedent proba- bility required for an intelligent solution of the problem, it gives no information whatever. So far as I can understand Prof. Peirce's method of arriving at a criterion, he takes two probabili- ties, both functions of probabilities of instructive error, and balances them against each other. This procedure reminds me of what sometimes happens in war, when two detachments of the same army meet in the dark and fire into each other, each supposing the other to belong to the common enemy. Prof. Peirce also seems to me to violate the fundamental principle of the science of probabili- ties, that probabilities must be independent in order that their product shall equal concurrent probability. If a computer resorts to the criterion when he feels that his own judgment is worthless, and only then, the criterion is harmless since it is of no importance whether a decision is made by a worth. less judgment or a worthless criterion. In the discussion that followed, Mr. A. Hall gave a brief account of the literature of the criteria which have been proposed for the rejection of doubtful observations. In addition to the criterion proposed by Prof. Peirce, which had been discussed by Mr. Doolit- tle, that of Mr. E. J. Stone was mentioned ; and also the proofs of a criterion given by Chauvenet and Watson. The advocacy of of Peirce's criterion by Gould, Winlock, Bache, Coffin, and Schott 156 PHILOSOPHICAL SOCIETY OF WASHINGTON. was noticed, and also its criticism by Airy, Stdne, and Glaisher, together with Glaisher's approval of De Morgan's method of treating observations. In conclusion, Mr. Hall said : The general result of what has been done in this matter appears to be as as follows : Every one can devise a criterion that suits himself, but it will not please other people. Now there seems to be a good reason underlying this. The attempt to establish an arbitrary and general criterion for the dis- cussion and rejection of observations is an attempt to eliminate from this work the knowledge and judgment of the investigator. Such an attempt ought to fail, and it certainly will fail at length, no matter by what personal influence it may be supported. It is true that no proof has been given of the principle of the arith- metical mean for a finite number of observations, such as the prac- tical cases that always come before us ; but we assume this principle as leading to the most probable result. When we depart from this principle, it must be done, I think, for reasons that are peculiar to each case, and there can be no better guide than the judgment of the investigator. It may be said that if the criteria that have been proposed be carefully managed they will do little harm, since the result of the arithmetical mean will be altered very little ; and in fact this is their chief recommendation. But by diminishing the value of the real probable error the criteria give to the observ- ations a fictitious accuracy and a weight they do not deserve. The paper was also discussed by Messrs. Hill, Elliott, Far- quhar, Woodward, and others, including Mr. James Main, a visitor—all agreeing, on essential points, with Mr. Doolittle's view. Mr. R. S. Woodward then discussed THE SPECIAL TREATMENT OF CERTAIN FORMS OF OBSERVATION-EQUATIONS. [Abstract. ] In a set of observation-equations whose type is x -}- (t — t ) y — n = v with weight p, in which t is an arbitrary constant, the same for each equation, and in which the residuals, v, are supposed to arise solely from errors in the observed quantities, n, it will be best to make • ~ [rf MATHEMATICAL SECTION. 157 This value of t makes the co-efficient of y in the first normal equation and the co-efficient of x in the second normal equation, zero, and hence gives directly [p(t-t )n] The weight of this value of x is a maximum ; i. e., the value of x corresponding to i = j—=, has a greater weight than the value of x correspondiDg to any other value of t . The probable error of the function x -f p-y is given by the simple formula. _______ A'. + A' in which s^ and s y are the probable errors of x and y, respectively. The investigation shows that, when several standards of length are to be intercompared two and two, in order to obtain the length of some one of them, it will be conducive to accuracy to have the mean temperatures of the several sets of comparisons equal. Remarks were made upon this communication by Mr. Kummell. Mr. Alex. S. Christie made a communication on CONTACT OF PLANE CURVES.* [Abstract.] Let = /(», y), (1), = (x), (3) be the equations of plane curves. Transferring the origin to (I, >?), where V = «K*)i writing /,

.fx= ti> ( (v„) ,Wl) + * ((»>n+0O . .+1 . to,) + x V ( (v6)vw3 + (v,) . v -f- 1 . w2 + (v2) . v + 2 . M>i) + &c. from (4, 6), ty» . ^ = x*(y ) vw, + a ^(v > . 2w2 + (vx> . lwj j + re " ( (O v . 3w3 + (v,) v . 2w2 + (v8) m . lwj + &c. •.• = (O . v - . v? + (vx) . — 1 . wl = (O . 2v - . r«3 + 00 . v- 1 . w2 + (va) . - 2 . w1 = (O . 3v - . w4+ (»0 . 2v - 1 . w3 + 2) . y-2 . w, + (v3) . - 3 . w1 ' = <>o) • mv — . tvm + x+ 0,) . (m — 1) v — 1 . wm + (v2) . (« - 2)v - 2 . u^-H-CO . (» - 3).-3 . wm _, + ••• + Om) • — m . wx MATHEMATICAL SECTION. 159 O © O o o o © X J w l © © O II I I ^ CO -a © 160 PHILOSOPHICAL SOCIETY OF WASHINGTON. which determines the coefficients in (4). (*) Putting u t3 for 1 f+s rl, si, d?6rt r, we have j t~v ~ (xTut) = x" ( (v ) uQV)+x ((v ) ux„V'., Ofj Q v+ 2 + Oi) wo") + x ( (vo) u%v + Oi) uxv + (ya) uQV) + &c, and this in (1') gives an equation of the form = a? A + xl A, + x2 A 2 + a? A3 + &c. (8) viz: = a? [(0 ) uj + xl [(0 ) m10 + (0,) u00 + (1 ) «oi] + as8 [(0 ) w20 + (00 m10 + (02) «w+ (1 ) wu + (l x)%+ (2 )O + «" [(0 ) «30+ (Ox) Mso+ (02 ) uw+ (03) iCo,, + (1 ) un+ (1, ) «u + (1 2 ) m01 + (2 ) u12 + (2X ) «02 + (3 ) w03] + &c. (8') for the abscissae of points common to (1) and (3). Similarly for the abscissae of points common to (2) and (3) we get an equation of the form = x° B + xl B x + x2 B.2 + x z B. s + &c. (9) viz : = x° [(0 ) t>00] + rf [(0 ) v10 + (0L) vm + (1 ) t>01] + &c. (9') Let (2) contain at least p parameters, enabling us to pass (2) through jo of the intersections of (1) with (3). When this is done we have the equation = x° (A — BQ) + x 1 (A x— Bx) + x2 (A 2—B2) -f &c. (10) true for the p values of x corresponding to the p points common to (1), (2), (3). Let the p common points move to the origin, (10) must have p roots equal zero, that is, = A — B , = A 1 -B 1,0 = A.i -B2,...0= A p - 1 -Bp - } (11) If we suppose (3) the parabolic representative of (1), x in (8) becomes indeterminate, and hence besides = A we have also = Av = A2, &c. that is, = /, with = d$~T~ did,] 1 &f — -v 2 76 Hough, F. B.: communication on the culti- vation of the Eucalyptus on the Roman Campagna 36 Hubbard, G. G.: remarks on fallacies con- cerning the deaf. - 82 Humidity observations 36 — of Alaska 36 Hydrometer determination of the specific gravity of solids 26 Hygrometer observations 36 Hypothesis, Utility ot, in science xxxiii Ichthyological results of the voyage of the Albatross 48 Idiots, Dumbness of 50, 83 Illinois, Loess hills of 97 Inaugural address of the Chairman of the Mathematical Section 117 Infinite and infinitesimal quantities 133 Initial meridian, Universal 106 Intermarriage of deaf mutes 74, 76,83 Intermittence of volcanoes 91 International Geodetic Association 100 Invitation to Anthropological and Biological Societies 8? Iowa, Loess of eastern 93 Kerr, W. C: communication On the geology of Hatteras and the neighboring coast .. 28 , Election to membership of. 33 Kinematic hypothesis, The xxviii King, A. F. A. : communication on The pre- vention of malarial diseases, illustrating, inter alia, the conservative function of ague. Knox, J. J.: communication on The distri- bution of the surplus money of the United States among the States 103 Kotzebue Sound ice cliffs 34 Kummell, C. H.: communication on Align- Page ment curves on any gurface, with spec- ial application to the ellipsoid 123 The theory of errors practi- cally tested by target shooting 138 : remarks on consequences of the re- lation of the circle to the equilateral hy- perbola 149 infinitesimals 135 refinement in the determina- tion of the temperature of the air 26 Lavas of the Hawaiian Islands 13 Lee, William : communication entitled Sketches from medallic medical history 39 Leadville ore deposits 32 Least-square computation 150 l.efavour, E. B. : remarks on infinitesimals... 135 Liagre's theory 139 List of members xvi Loess of eastern Iowa 93 Longitudes, Unification of 106 McCullough, Hugh : remarks on money de- posited by the United States with the State of Indiana 106 McDowell, Silas : cited on thermal belts of North Carolina 11,12 McGee, W J : communication on The drain- age system and the distribution of the loess of eastern Iowa 93 Malarial diseases, Prevention of. 5 Mallery, Garrick: election as Vice-president 41 Mallet's theory of volcanism 90 Marriage of deaf mutes 74,76,83 Mass of planets, Determination of 132 Mathematical Section, Address by Chair- man of the 117 , Bulletin of the 113,121 , Committee of the 135, 161 , Members of the 116 , Officers of the 122 .Organization of the 28, 121 , Rules of 115, 135 Mathematics (see Arithmetic, Formulas, Math- ematical Section.) Matter, Combination of xxxv Maxima and minima 149 Medallic medical history 39 Melanosis, Malarial 7 Members, List of xvi — of the Mathematical Section 116 Meridian, Universal initial 106 Metamorphic deposits 32 Metamorphism and subsidence 93 Meteorology (see Climate, Humidity, Hygro- meter, Temperature, Thermal, Thermome- ter.) INDEX. 167 Page. Metric system discussed 4 Minerals, Separation of, by density 26 Modes of motion xxxviii Moon's motion, Pertubations of the 13G Morgan, E. C, Election to membership of ... 87 Mosquito, Inoculation by the 7 Motion, Modes of xxxviii, xli Munroe, C. E. : communication on the De- termination of the specific gravity of solids by the common hydrometer 26 Mutes, Fallacies concerning 49,78 Natural language 64, 70, 75, 79 Nature, The, of matter 5 Nebular hypothesis and volcanic eruption... 87 not discredited by Saturnian and Mar- tial periods 45 North Carolina, Geology of 28 , Thermal belts of 11 Notation, New arithmetic 3, 38 Note on the rings of Saturn 41 Observation-equations 156 Observations, Rejection of doubtful 152 Officers of the Mathematical Section 28, 122 Society xiv, xv Ore deposition by replacement 32 Peat beds of North Carolina 28 Periapsis 183 Periods, Saturnian 43 Perpetual Calendar 135 Pertubations, Lunar 136 Physical evolution xliii Picture language 84 Porter, Sarah : cited on the use of signs by deaf-mute children 81 Powell, J. W. : address as President xxv : remarks on the drainage system of eastern Iowa 97 loess of western Illinois 97 volcanic eruption 92, 93 President's annual address xxv Prevention of malarial disease 5 Proorthode, The 123 Quasi general differentiation, A 122 Recent experiments on serpent venom 38 Rejection of doubtful observations 152 Renshawe, J. H., Election to membership of, 14 Replacement in ore deposition 32 Report of the Treasurer xxi — of Auditing Committee 5 Response, The, of terrestrial climate to va- riations in solar radiation 10 Page. Riley, C. V., Election of, as member of the General Committee 41 Rings of Saturn 41 Rules for the publication of the Bulletin xiii — , New, on papers read before sections 38 — , Standing, of the General Committee xii Mathematical Section 115 Society ix Russell, Thomas, Election to membership of, 10 Salmon, D. E., Election to membership of.... Ill Sampson, W. T., Election to membership of, 36 Sands, B. F., Death of 41 Saturn's rings 41 "Science" to report the scientific proceed- ings of the Society 5,122 Seismographic record obtained in Japan 38 Shelters for thermometers 4G Sibscota, George : cited on the cause ofdumb- ness 49 Sign language of the deaf 63, 66, 71, 75, 79, 84 Sketches from medallic medical history 39 Skinner, J. O., Election to membership of.... 36 Smith, Edwin : communication on a Seismo- graphic record obtained in Japan 87 Smithsonian investment 105 Solar radiation in its relation to climate 10 Sound velocity as a measure of air tempera- ture 47 Speech and thought 53, 81 — reading by the eye 56, 60, 70, 76, 78, 84 Special case, A, in maxima and minima 149 — treatment of certain forms of observation- equations 156 Specific gravities, Determination of. 26 Standard time 106 Standing rules (See Bules). Substance, matter, motion, and force 14 Surplus money, Distribution of 103 Survival of the fittest, not the law of an- thropic evolution xlvii, lii Taylor, W. B. : communication entitled Note on the rings of Saturn 41 : remarks on binary arithmetic 4 designation of apsides 133 infinitesimals 135 thermometrie observation 47 Target shooting 139 Temperature of the air 24, 46, 47 The theory of errors practically tested by target shooting 133 The thermal belts of North Carolina 11 Thermometer exposure 24, 26 Thought and speech 53, 81 Three methods, The, of evolution xxvii Topographical indications of a fault near Harper's Ferry 30 168 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Transit of Venus 21 Treasurer's annual report xxii — accounts for 1882, Report of Auditing Committee on the 5 Unification of longitudes and time 106 Units of force and energy, including electric units 137 Universal time 106 Velocity of sound as a measure of air tem- perature 47 Venus, Transit of 21 Volcanic problem, The, stated 87 Walcott, C. D. : communication on The Cam- brian system in the United States and Page Canada * 98 , Election to membership of 48 Walling, H. P.: communication on Topo- graphical indications of a fault near Har- per's Ferry 30 , Election to membership of 14 Ward, L. F. : remarks on Dismal Swamp 30 Water, a factor in volcanic eruption 87 White, C. A. : remarks on the drainage sys- tems of Iowa 97 instability of continents.... 93 Williams, Albert, Jr., Election to member- ship of. 14 Woodward, R. S. : communication on the Special treatment of certain forms of ob- servation-equations 156 , Election to membership of. Ill BULLETIN PHILOSOPHICAL SOCIETY WASHINGTON. VOL. VII. Containing the Minutes of the Society and of the Mathematical Section for the year 1884. PUBLISHED BY THE CO-OPERATION OF THE SMITHSONIAN INSTITUTION. 15 WASHINGTON 1885. CONTENTS Page. Constitution . vn Standing Rules of the Society ix Standing Rules of the General Committee XII Rules for the Publication of the Bulletin xrn Officers elected December, 1883 xiv Officers elected December, 1884 xv List of Members, corrected to December 31, 1884 xvi Calendar xxir Annual Report of the Secretaries xxin Annual Report of the Treasurer xxiv Annual Address of the President, J. C. Welling xxix Bulletin of the General Meeting 1 The Rochester (Minnesota) tornado, J. R. Eastman 3 Recent advances in our knowledge of the limpets, W. H. Dall. 4 The existing glaciers of the High Sierra of California, I. C. Russell 5 The mica mines of North Carolina, W. C. Kerr 9 Recent advances in economic entomology, C. V. Riley 10 Why the eyes of animals shine in the dark, S. M. Burnett 13 Some eccentricities of ocean currents, A. B. Johnson 14 The periodic law of chemical elements, F. W. Clarke 15 The sun-glows, H. A. Hazen 17 The application of physical methods to intellectual science, R. D. Mussey 18. Deposits of volcanic dust in the Great Basin, I. C. Russell 18 Some physical and economic features of the upper Missouri sys- tem, Lester F. Ward 20 The diversion of water courses by the rotation of the earth, G. K. Gilbert 21 The relations between northers and magnetic disturbances at Havana, G. E. Curtis, {Titleonly) 25 Composite photography applied to craniology, J. S. Billings. _ 25 Fisheries exhibitions, G. B. Goode, (Titleonly) 26 Music and the chemical elements, M. H. Doolittle 26, 27 Review of the theoretical discussion in Prof. P. G. Tait's " En- cyclopaedia Britannica" article on mechanics, H. Farquhar. 29 A new meteorite, J. R. Eastman 32 Certain appendages of the mollusca, W. H. Dall, (Title only). 32 III IV CONTENTS. The volcanic sand which fell at Unalashka, October 20, 1883, and some considerations concerning its composition, J. S. Diller 33 The methods of modern petrography, G. H. Williams' 36 "What is a glacier? [Symposium) 37 The physical basis of phenomena, H. H. Bates 40 The strata exposed in the east shaft of the water-works exten- , sion, T. Robinson 69 Plan for the subject bibliography of North American geologic literature, G K. Gilbert and J. W. Powell 71 Are there separate centres for light- form- and color-percep- tion? S.M.Burnett 72 "Was the earthquake of September 19th felt in the District of Columbia? T. Robinson 73 Natural naturalists, "Washington Matthews 73 Resolutions on the death of Dr. "Woodward 75 The volcanoes and lava fields of New Mexico, C. E. Dutton __ 76 Electric lighting, E. B. Elliott, {Title only) 80 Thermometer exposure, H. A. Hazen 80 Presentation of the annual address 81 Annual Meeting 81 Bulletin of the Mathematical Section 83 Standing Rules of the Section 85 Officers of the Section 86 Curves similar to their evolutes, C. H. Kummell 87 The problem of the knight's tour, G. K. Gilbert 88 Empirical formula? for the diminution of amplitude of a freely- oscillating pendulum, H. Farquhar 89 A concrete jiroblem in hydrostatics, G. K. Gilbert 92 The formula? for computing the position of a satellite, A. Hall- 93 A formula for the length of a seconds-pendulum, G. "W. Hill, (Title only) 101 A form of the multinomial theorem, A. S. Christie, (Title only). 101 Discussion of a concrete problem in hydrostatics proposed by Mr. G. K. Gilbert, R. S. Woodward, (Title only) 101 The quadric transformation of elliptic integrals, combined with the algorithm of the arithmetico-geometric mean, C. H. Kummell 101,102 A case of discontinuity in elliptic orbits, W. B. Taylor 122 The verification of predictions, M. H. Doolittle 122 Memorial to Gen. Alvord 127 Committees on mathematical communications 129 Index 131 BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. CONSTITUTION, RULES, OFFICERS AND MEMBERS, AND RKPORTS OF SECRETARIES AND TREASURER. CONSTITUTION THE PHILOSOPHICAL SOCIETY OF WASHINGTON. Article I. The name of this Society shall be The Philosophi- cal Society of Washington. Article II. The officers of the Society shall be a President, four Vice-Presidents, a Treasurer, and two Secretaries. Article III. There shall be a General Committee, consisting of the officers of the Society and nine other members. Article IV. The officers of the Society and the other members of the General Committee shall be elected annually by ballot ; they shall hold office until their successors are elected, and shall have power to fill vacancies. Article V. It shall be the duty of the General Committee to make rules for the government of the Society, and to transact all its business. Article VI. This constitution shall not be amended except by a three-fourths vote of those present at an annual meeting for the election of officers, and after notice of the proposed change shall have been given in writing at a stated meeting of the Society at least four vjeeks previously. vii STANDING RULES FOR THE GOVERNMENT OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. 1. The Stated Meetings of the Society shall be held at 8 o'clock p. M. on every alternate Saturday ; the place of meeting to be designated by the General Committee. 2. Notice of the time and place of meeting shall be sent to each member by one of the Secretaries. When necessary, Special Meetings may be called by the President. 3. The Annual Meeting for the election of officers shall be the last stated meeting in the month of December. The order of proceedings (which shall- be announced by the Chair) shall be as follows : First, the reading of the minutes of the last Annual Meeting. Second, the presentation of the annual reports of the Secretaries, including the announcement of the names of members elected since the last annual meeting. Third, the presentation of the annual report of the Treasurer. Fourth, the announcement of the names of members who, having complied with Section 13 of the Standing Rules, are entitled to vote on the election of officers. Fifth, the election of President. Sixth, the election of four Vice-Presidents. Seventh, the election of Treasurer. Eighth, the election of two Secretaries. Ninth, the election of nine members of the General Committee. Tenth, the consideration of Amendments to the Constitution of the Society, if any such shall have been proposed in accordance with Article VI of the Constitution. Eleventh, the reading of the rough minutes of the meeting. ix X PHILOSOPHICAL SOCIETY OF WASHINGTON. 4. Elections of officers are to be held as follows : ' In each case nominations shall be made by means of an informal ballot, the result of which shall be announced by the Secretary ; after which the first formal ballot sliall be taken. In the ballot for Vice-Presidents, Secretaries, and Members of the General Committee, each voter shall write on oue ballot as many names as there are officers to be elected, viz., four on the first ballot for Vice-Presidents, two on the first for Secretaries, and nine on the first for Members of the General Committee ; and on each subse- quent ballot as many names as there are persons yet to be elected ; and those persons who receive a majority of the votes cast shall be declared elected. If in any case the informal ballot result in giving a majority for any one, it may be declared formal by a majority vote. 5. The Stated Meetings, with the exception of the annual meet- ing, shall be devoted to the consideration and discussion of scientific subjects. The Stated Meeting next preceding the Annual Meeting shall be set apart for the delivery of the President's Annual Address. 6. Sections representing special branches of science may be formed by the General Committee upon the written recommenda- tion of twenty members of the Society. 7. Persons interested in science, who arc not residents of the Dis- trict of Columbia, may be present at any meeting of the Society, except the annual meeting, upon invitation of a member. 8. Similar invitations to residents of the District of Columbia, not members of the Society, must be submitted through one of the Secretaries to the General Committee for approval. 9. Invitations to attend during three months the meetings of the Society and participate in the discussion of papers, may, by a vote of nine members of the General Committee, be issued to persons nominated by two members. 10. Communications intended for publication under the auspices of the Society shall be submitted in writing to the General Com- mittee for approval. STANDING KTJLES. XI 11. Any paper read before a Section may be repeated, either entire or by abstract, before a general meeting of the Society, if such repetition is recommended by the General Committee of the Society. 12. New members may be proposed in writing by three members of the Society for election by the General Committee ; but no per- son shall be admitted to the privileges of membership unless he signifies his acceptance thereof in writing within two months after notification of his election. 13. Each member shall pay annually to the Treasurer the sum of five dollars, and no member whose dues are unpaid shall vote at the annual meeting for the election of officers, or be entitled to a copy of the Bulletin. In the absence of the Treasurer, the Secretary is authorized to receive the dues of members. The names of those two years in arrears shall be dropped from the list of members. Notice of resignation of membership shall be given in writing to the General Committee through the President or one of the Secre- taries. 14. The fiscal year shall terminate with the Annual Meeting. 15. Members who are absent from the district of Columbia for more than twelve months may be excused from payment of the annual assessments. They can, however, resume their membership by giving notice to the President of their wish to do so. 16. Any member not in arrears may, by the payment of one hundred dollars at any one time, become a life member, and be relieved from all further annual dues and other assessments. All moneys received in payment of life membership shall be invested as portions of a permanent fund, which shall be directed solely to the furtherance of such special scientific work as may be ordered by the General Committee. STANDING RULES OF THE GENERAL COMMITTEE OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. 1. The President, Vice-Presidents, and Secretaries of the Society shall hold like offices in the General Committee. 2. The President shall have power to call special meetings of the Committee, and to appoint Sub-Committees. 3. The Sub-Committees shall prepare business for the General Committee, and perform such other duties as may be entrusted to them. 4. There shall be two Standing Sub-Committees ; one on Com- munications for the Stated Meetings of the Society, and another on Publications. 5. The General Committee shall meet at half-past seven o'clock on the evening of each Stated Meeting, and by adjournment at other times. 6. For all purposes except for the amendment of the Standing Rules of the Committee or of the Society, and the election of mem- bers, six members of the Committee shall constitute a quorum. 7. The names of proposed new members recommended in con- formity with Section 11 of the Standing Rules of the Society, may be presented at any meeting of the General Committee, but shall lie over for at least four weeks before final action, and the concur- rence of twelve members of the Committee shall be necessary to election. The Secretary of the General Committee shall keep a chronologi- cal register of the elections and acceptances of members. 8. These Standing Rules, and those for the government of the Society, shall be modified only with the consent of a majority of the members of the General Committee. xii IE^TTXjIES FOR THE PUBLICATION OF THE BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. 1. The President's annual address shall be published in full. 2. The annual reports of the Secretaries and of the Treasurer shall be published in full. 3. When directed by the General Committee, any communication may be published in full. 4. Abstracts of papers and remarks on the same will be pub- lished, when presented to the Secretary by the author in writing within two weeks of the evening of their delivery, and approved hj the Committee on Publications. Brief abstracts prepared by one of the Secretaries aud approved by the Committee on Publications may also be published. 5. If the author of any paper read before a Section of the Society desires its publication, either in full or by abstract, it shall be referred to a committee to be appointed as the Section may determine. The report of this committee shall be forwarded to the Publica- tion Committee by the Secretary of the Section, together with any action of the Section taken thereon. 6. Communications which have been published elsewhere, so as to be generally accessible, will appear in the Bulletin by title only, but with a reference to the place of publication, if made known in season to the Committee on Publications. xiii OFFICERS OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON Elected December 22, 1883. President J. C. WELLING. Vice-Presidents J. S. Billings. Garrick Mallerv. J. E. Hilgard. Asaph Hall. Treasurer-* Cleveland Abbe. Secretaries Henry Farquhar. G. K. Gilbert. MEMBERS AT LARGE OF THE GENERAL COMMITTEE. H. H. Bates. E. B. Elliott. W. H. Dall. Robert Fletcher; C. E. Dutton. William Harkness. J. R. Eastman. J. J. Knox. * C. V. Riley. STANDING COMMITTEES. On Communications : J. S. Billings, Chairman. Henry Farquhar. G. K. Gilbest. On Publications : G. K. Gilbert, Chairman. Cleveland Abbe. Henry Farquhar. S. F BAIRDf * Mr. Knox resigned May 10, 1884, and the General Committee elected Mr. F. W. Clark to the vacancy. + As Secretary of the Smithsonian Institution. XIV OFFICERS PHILOSOPHICAL SOCIETY OF WASHINGTON Elected December 20, 1884. President ASAPH HALL. Vice-Presidents J. S. Billings. GARRICK MALLERY. William Harkness. J. E. Hilgard. Treasurer Robert Fletcher. Secretaries G. K. Gilhert. Henry Farquhar. MEMBERS AT LARGE OF THE GENERAL COMMITTEE. Marcus Baker. F. W. Clarke. C. E. Dutton. E. B. Elliott. H. H. Bates. W. H. Dall. J. R. Eastman. H. M. Paul. C. V. Riley. STANDING COMMITTEES. On Commnuications : J. S. Billings, Chairman. G. K. Gilbert. Henry Farquhar. On Publications : G. K. Gilbert, Chairman. Robert Fletcher. Henry Farquhar. S. F. Baird.* As Secretary of the Smithsonian Institution. LIST OF MEMBERS OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. Corrected to December 20, 1884. The names of founders are printed in Small Capitals. (d) indicates deceased. (a) indicates absent from the District of Columbia and excused from payment of dues until announcing his return, (r) indicates resigned. NAME. P. O. Address and Residence. Date orAdmission. Abbe, Cleveland Abert, Sylvanus Thayer. Adams, Henry Aldis, Asa Owen Allen, James Alvord, Benjamin (d) Antisell, Thomas Avery, Robert Stanton..., Army Signal Office. 2017 I St. N. W. 1724 Penn. Ave. N. W 1G07 H St. N. W 1765 AIis 6*. Ay© Army Signal Office'.'" 'l907 i's't'.N.'w.'. Patent Office. 1311 QSt. N. W Coast and Geodetic Survey Office. 320 A St. S. E. Babcock, Orville Elias (d). Bailey, Theodoras (d) Baird, Spencer Fullerton. Baker, Frank.. Baker, Marcus. Bancroft, George Barnard, William Stebbins. Barnes, Joseph K. (d) Bates, Henry Hobart Bean, Tarleton Hoffman Beardslee, Lester Anthony (a). Bell, Alexander Graham Bell, Chichester Alexander Ben£t, Stephen Vincent Smithsonian Institution. 1445 Mass. Ave. N. W. 326 C St. N. W Coast and Geodetic Survey Office. 1205 Rhode Island Ave. 1023 II St, N. W., or Newport, R. I .i (Agricultural Department. 917 N. Y. Ave. N. W., or Canton, 111. Bessels, Emil Billings, John Shaw. Birney, William Birnie, Rogers (a) Blair, Henry Wayne (d).. Bodfish, Sumner Homer.. Boutelle, Charles Otis Bowles, Francis Tiffany. Brown, Stimson Joseph . Browne, John Mills Patent Office. The Portland National Museum. 1411 R. I. Ave Captain IT. S. N., Navy Department... Scott Circle. 1500 R. I. Ave 1221 Conn. Ave Ordnance Office, War Department, 1717 I St. N. W. Smithsonian Institution. 1444 N St. N. W. Surg. Genl's Office, U. S. A. 3027 N St, N. W. 450 Louisiana Ave. 1901 Harewood Ave., Le Droit Park. Cold Spring, Putnam Co., N. Y Burchard, Horatio Chapin Geological Survey. G05 F St. N. W.... Coast and Geodetic Survey Office. 1513 20th St. N. W. 18f!3 Jefferson Place Naval Observatory. 2133 K St. N.W.. Medical Director, U. S. N. The Port- land. Director of the Mint. Riggs House.. XVI 1871 1875 1881 1873 1882 1872. 1871 1879 1871 1873 1871 1881 1876 1875 18S4 1871 1871 1884 1875 1879 1881 1S71 1875 1871 1879 1876 1884 1883, 1884, 1884, 1884. 1883, Oct. 29 Jan. 30 Feb. 5 Mn r. 1 Feb. 25 Mar. 23 Mar. 13 Oct. 11 June 9 Mar. 1 Mar. 13 May 14 Mar. 11 Jan. 16 Mar. i Mar. 13 Nov. 4 Apr. 26 Feb. 27 Mar. 29 Oct. 8 Mar. 13 Jan. 16 Mar. 13 Mar. 29 Mar. 11 Fob. 2 Mar. 24 Feb. 16 Mar. 29 Apr. 12 Nov. 24 1879, May 10 LIST OF MEMBERS. XVII NAME. P. 0. Address and Residence. Date ofAdmission. Burgess, Edward Sandford. Burnett, Swan Moses Busey, Samuel Clagett Capron, Horace Case, Augustus Ludlow (n). Casey, Thomas Lincoln High School. 810 12th St. N. W- 1215 I St. N. W 1525 I St. N. W Caziarc, Louis Vasmer(a) Chase, Salmon Portland (d) Chamberlin, Thomas Crowder. Chickering, John White, .Tr Christie, Alexander Smyth Clapp, William Henry (a). Clark, Edward The Portland Bristol, R. I Col. Corps of Engineers. 1419 K St. N. W. War Department Clark, Ezra Westcote.. Clarke, Frank Wigglesworth Coffin, John Huntington Crane. Collins, Frederick (d) Comstock, John Henry (a) Coues, Elliott Craig, Benjamin Faneuil (d) Craig, Robert Craig, Thomas (a) Crane, Charles Henry (d) Curtis, George Edward Curtis, Josiah (d) Cutts, Richard Dominicus (d) .... Dall, William Healey .... Davis, Charles Henry (d). Davis, Charles Henry Geological Survey Deaf Mute College, Kendall Green... Coast and Geodetic Survey Office. G2S Mass. Ave. N. W. Ft. Davis, Tex. 1416 Corcoran St. Washington. Architect's Office, Capitol. 417 4th St. N. W. Revenue Marine Bureau, Treasury Department. Wood ley Road. Geological Survey. 1425 Q St. N. W.. 1901 I St. N. W ... ... Cornell University, Ithaca, N. Y Smithsonian Inst. 1726 N. St. N. W. Army Signal Office. 1008 I St. N. W.. Johns Hopkins Univ., Baltimore, Md. Army Signal Office. 1416 Corcoran St. Care Smithsonian Institution. 12th St. N. W. Dean, Richard Grain (a) , De Caindry, William Augustin., De Land, Theodore Louis... Dewey, Frederick Perkins. Dewey, George (r) Diller, Joseph Silas , Doolittle, Myrick Hascall ... Navy Department. 1705 Rhode Island Ave. N. W. Naval Hospital, New York Commissary General's Office. 924 19th St. N. W. Treasury Da»t. 120 7th St. N. E National Museum. 1007 G St. N. W.... Dorr, Frederic William (d) Dun\voody,HenryHarrison Chase(a) Dutton, Clarence Edward. Dyer, Ai.f.xander B. (d) Geological survey Coast and Geodetic Survey Office. 1925 I St. N. W. Army Signal Office. 3012 Dumbarton St., Georgetown. Geological Survey Earll, Robert Edward . Eastman, John Robie.. Eaton, Amos Beebe (d). Eat <:'ii, John National Museum , Naval Observatory. 1823 I St. N. W. Limbeck, William Eldredge, Stewart (a) Elliot, George Henry (r). Elliott, Ezekiel Brown... Emmons, Samuel Franklin. Bureau of Education, Interior Dept. 712 East Capitol St. Coast and Geodetic Survey Office Yokohama, Japan Endlich, Frederic. Miller (a) . Ewing, Charles (d). Ewing, Hugh (a).... Government Actuary, Treasury De- partment. 1210 G St. N. W. Geological Survey. 23 Lafayette Place. Smithsonian Institution. Lake Val- ley, New Mexico. Farquhar, Edward. 16 ' Lancaster, Ohio Patent Office'Library. 1915 H St. N.W.. 1883, Mar. 24 1S79, Mar. 29 1874, Jan. 17 1871, Mar. 13 1872, Nov. 16 1871, Mar. 13 1882, Feb. 25 1871, Mar. 13 1883, Mar. 24 1874, Apr 11 1880, Dec. 4 1882, Feb. 25 1877, Feb. 24 1882, M;r. 25 1874, 1871, 1879, 1880, 1874, 1871, 1873, 1879, 1871, 18S4, 1874, 1871, Apr. 11 Mar. 13 Oct. 21 Feb. 14 Jan. 17 Mar. 13 Jan. 4 Nov. 22 Mar. 13 Jan. 5 Mar. 28 Apr. 29 1871, Mar. 13 1874, Jan. 17 1880, June 19 1872, Apr. 23 1881, Apr. 30 18S0, Dec. 18 1884, Apr. 25 1879, Feb. 15 1881, Mar. 1 1876, Feb. 12 1874, Jan. 17 1873, Dec. 20 1872, Jan. 27 1871, Mar. 13 1884, Apr. 26 1871, Mav 27 1871, Mar. 13 1874, May 8 1884, Feb. 2 IsTl, June 9 1871, Mar. 13 1871, Mar. 13 1883, Apr. 7 1873, Mar. 1 1874, Jan. 17 1874, Jan. 17 1876, Feb. 12 XVIII PHILOSOPHICAL SOCIETY OF WASHINGTON. NAME. Farquhar, Henry. Ferrel, William ... Fletcher, Robert.. Flint, Albert Stowell. Flint, James Milton Footk, Elisha (d) Foster, John Gray (d) French, Henry Flags (»')• Fristoe, Edward T Gale. Leonard Dunnell (d). Gallaudet, Edward Miner.. Gannett, Henry Gardiner, James Terry (a) Garnett, Alexander Young P. (r).. Gihon, Albert Leary Gilbert, Grove Karl , Gill, Theodore Nicholas... Godding, William Whitney. Goode, George Brown Goodfellow, Edward Goodfellow, Henry (r) Gore, James Howard Graves, Edward Oziel (a) Graves, Walter Hayden (a) Greely, Adolphus Washington- Green, Bernard Richardson Green, Francis Mathews (a) Greene, Benjamin Franklin (a) Greene, Francis Vinton Gregory, John^Milton. Gunnell, Francis M Hains, Peter Conover Hall, Asaph Hall, Asaph, jr Hanscom, Isaiah (d) Harkness, William Hassler, Ferdinand Augustas (a)... Hayden, Ferdinand Vandeveer (a). Hazen, Henry Allen Hazen, William Babcock.. Heap, David Porter Henry, Joseph (d) Henshaw, Henry Wetherbee., Hii.gard, Julius Erasmus , Hill, George William.. Hitchcock, Romyn Holden, Edward Singleton (a) Holmes, William Henry Hough, Franklin Benjamin (a) Howell, Edwin Eugene (a) Humphreys, Andrew Atkinson (d)... Jackson, Henry Arundel Lambe (a) Jnmes, Owen (a) Jeffers, William Nicolson (r) Jenkins, Thornton Alexander P. O. Address and Residence. Coast and Geodetic Survey Office. Brooks Station, D. C. Arrnv Signal Office. 471 C St. N. W... Surgeon Genl's Office, U. S. A. 1326 L St. N. W. Naval Observatory. 1450 Chapin St., College Hill. Navy Dept. U. S. S. Albatross 1434 N St. N. W. Deaf Mute College, Kendall Green... Geological Survey. 1881 Harewood Ave., Le Droit Park. State Survey, Albany, N. Y Naval Hospital, 2019 Hillyer Place N. W. Geological Survey. 1424 Corcoran St.. Smithsonian Institution Government Asylum for the Insane. National Museum. 1620 Mass. Ave. N. W. Coast and Geodetic Survey Office Columbian Univ. 1305 Q St. N. W.. Asst. Treasurer U. S Denver, Colorado Army Signal Office. 1909 I St 1738 N St. N. W Navy Department West Lebanon, N. H District Commissioners' Office, 1915 G St. N. W. 15 Grant Place Surgeon General, U. S. N. 600 20th St. N. W. Ijf24 Jefferson Place. Naval Observatory. Naval Observatory. 2715 N St. N. W.. 2715 N St. N. W.. Naval Observatory. 1415 G St. N. W. Santa Ana, Los Angeles Co.. Cal Geological Survey. 1803 Arch St., Phil- adelphia, Penn. P. O. Box No. 427. 1416 Corcoran St... Army Signal Office. 1601 K. St. N. W.. Light House Board,Treasury Depart- ment. 1018 Rhode Island Ave. Bureau of Ethnology, P. O. Box 585... Coast and Geodetic Survey Office. 1709 Rhode Island Ave. N. W. Nautical Almanac Office. 314 Ind. Ave. N. W. P. O. Box 630 Madison, Wisconsin Geological Survey. 1100 O St. N. W... Agricultural Dept. Lowville, N. Y Rochester N. Y War Department.. Scran ton, Pa 2115 Penn. Ave. N. W. Date or Admission. 1881, May 14 1872, Nov. 16 1873, Apr. 10 18S2, Mar. 25 1881, Mar. 19 1871, Mar. 13 1873, Jan. 18 1882, Mar. 25 1873, Mar. 29 1874, Jan. 17 1875, Feb. 27 1874, Apr. 11 1S74, Jan. 17 1878, Mar. 16 1880, Dec. 18 1873, June 7 1871, Mar. 13 1879, Mar. 29 1874. Jan. 31 1875, 1871, 1880, 1874, 1878, 1880, 1879, 1875, 1871, 1875, Dec. 18 Nov. 4 Mar. 14 Apr. 11 May 25 June 19 Feb. 15 Nov. 9 Mar. 13 Apr. 10 1884, Mar. 29 1879, Feb. 1 1879, Feb. 15 1871, Mar. 13 1880. Dec. 20 1873, Dec. 20 1871, Mar. 13 1880, May 8 1871, Mar. 13 1882, Mar. 25 1881, Feb. 5 1884, Mar. 15 1871, Mar. 13 1874, Apr. 11 1871, Mar. 13 1879, Feb. 1 1884, Apr. 26 1873, June 21 1879, Mar. 29 1879, Mar. 29 1874, Jan. 31 1871, Mar. 13 1875, Jan. 30 1880, Jan. 3 1877, Feb. 24 1871, Mar. 13 LIST OF MEMBERS. XIX NAME. Johnson, Arnold Bulges.. Johnson, Joseph Taber... Johnson, Willard Drake.. Johnston, William Waring.. Kampf, Ferdinand (d) Kauffmann, Samuel Hays Keith, Keuel Kerr, Mark Brickell Kerr, Washington Caruthers (a) Kidder, Jerome Henry Kilbourne, Charles Evans (a) King, Albert Freeman Africanus.. King, Clarence (r) Knox, John Jay (a) Kummell, Charles Hugo Lane, Jonathan Homer (d). Lawrence, William Lawyer, Winfield Peter. Lee, William Lefavour, Edward Brown. Lincoln, Nathan Smith... Lockwood, Henry H. (r). Loomis, Eben Jenks Lull, Edward Phelps (a).. Lyford, Stephen Carr (r). MacCauley, Henry Clay (a) McGee, W J McGuire, Frederick Bauders. Mack, Oscar A. (d) , McMurtrie, William (a). Maher, James Arrau Mallery, Garrick Marcou, John Belknap Marvin, Joseph Badger (a) Marvin, Archibald Robertson (d).. Mason, Otis Tufton Matthews, Washington Meek, Fielding Bradford (d) Meigs, Montgomery (a) Meigs, Montgomery Cunningham... Merrill, George Perkins Milner, James William (d) Morgan, Ethelbert Carroll Morris, Martin Ferdinand (r) Murdoch, John Mussey, Reuben Delavan. Myer, Albert J. (d) Myers, William (a) Newcomb, Simon Nichols, Charles Henry (a)., Nicholson, Walter Lamb Nordhoff, < 'harles , Norris, Basil , Ogden, Herbert Gouverneur. Osborne, John Walter P. O. Address and Residence. Light House Board, Treasury Dept. 501 Maple Ave., Le Droit Park. 926 17th St. N. W Geological Survey. 501 Maple Ave., Le Droit Park. 1603 K St. N. W 1000 M St. N. W 2219 I St Geological Survey. 812 21st St. N. W. Raleigh, N. C Smithsonian Inst. 1816 N St., N. W... War Department 720 13th St. N. W Nat. Bk. Republic, New York City... Coast and Geodetic Survey Office. 608 Q St. N. W. First Comptroller's Office, Treasury Department. 1344 Vermont Ave. Mint Bureau, Treasury Department. 1912 I St. N. W. 2111 Penn. Ave. N. W Coast and Geodetic Survey Office. 905 O St. N. W. 1514 H St. N W Nautical Almanac Office. 1413 Col- lege Hill Terrace N. W. 74 Cedar St., Roxbury, Mass P. O. Box 953, Minneapolis, Minn Geological Survey. 1424 Corcoran St, 1306 F St. N. W. 614 E. St. N. W Champaign, 111 Geological Survey. 21 E St. N. W..„. Bureau of Ethnology, P. O. Box 585. 1323 N St. N. W. Geological Survey Internal Revenue Bureau National Museum. 1305 Q St. N. W.. Surgeon General's Office, U. S. A U. S. Engineer Office, Keokuk, Iowa. 1239 Vermont Ave. N. W National Museum 918 E St. N. W. Smithsonian Institution. 1441Chapin St., College Hill. P. O. Box 618. 508 5th St. N. W , War Department.. Navy Department Bloomingdale, N. Y. 1322 I St. N. W 1731 KSt 1829 G St. N. W Coast and Geodetic Survey Office. 1324 19th St. N. W. 212 Delaware Ave. N. E_ Date of Admission. 1878, Jan. 19 1879, Mar. 29 1884, Feb. 16 1873, Jan. 21 Dec. 18 Feb. 16 Oct. 29 Feb. 16 Apr. 7 May 8 June 19 Jan. 16 May 10 May 8 Mar. 25 1875, 1884, 1871, 1884, 1883, 1880, 1880, 1875, 1879, 1874, 1882, 1871, Mar. 13 1884, Feb. 16 1881, Feb. 19 1874, Jan. 17 1882, Dec. 16 1871, May 27 1871, Oct. 29 1880, Feb. 14 1875, Dec. 4 1873, Jan. 18 1880, Jan. 3 1883, Nov. 10 1879, Feb. 15 1872, Jan. 27 1876, Feb. 26 1884, Feb. 16 1875, Jan. 30 1884, 1878, 1874, 1875, 1884. 1871, 1877, 1871, 1884, 1874, 1883, 1877, 1884, Mar. 29 May 25 Jan. 31 Jan. 30 June 7 Mar. 13 Mar. 24 Mar. 13 Apr. 26 Jan. 31 Oct. 13 Feb. 24 Apr. 26 1881, Dec. 3 1871, Mar. 13 1871, June 23 1871, Mar. 13 1872, May 4 1871, Mar. 13 1879, May 10 1884, Mar. 1 1784, Feb. 2 1878, Dec. 7 XX PHILOSOPHICAL SOCIETY OP WASHINGTON. NAME. P. O. Address and Kesidejwe. Date of Admission. Otis, Geokge Alexander (d). Parke, John Grubc Parker, Peter.. Parry, Charles Christopher (a).. Patterson, Carlile Pollock (a).... Paul, Henry Martyn Peale, Albert Charles Engineer Kureau, War Department. 16 Lafayette Square. 2 Lafayette Square Davenport, Iowa Peale, Titian Ramsay (a) Peirce, Benjamin (d) Peirce, Charles Sanders (a).... Pilling, James Constantine.... Poe, Orlando Metcalfe (a) Poindexter, William Mundy.. Pope, Benjamin Franklin Porter, David Dixon (r) Powell, John Wesley , Prentiss, Daniel Webster Pritchett, Henry Smith (a).. Naval Observatory. 109 1st St. N. E.. Geological Survey. 1010 Mass. Ave. N. W. Philadelphia, Penn Coast and Geodetic Survey Office Geological Survey. 918 M St. N. W.. 34 Congress St. West, Detroit, Mich.. 701 15th St. N. W. 80fi 17th St. N. W. Surgeon General's Office, U. S. A. 1309 20th St. N. W. Geological Survey. 910 M St. N. W... 1224 9th St. N. W Washington University, St. Louis, Mo. Rathbone, Henry Reed (a).. Rathbun, Richard Ray, Patrick Henry , Renshawe, John Henry.., Richey, Stephen Olin Ricksecker, Eugene , Ridgway, Robert (a) Riley, Charles Valentine.. Riley, John Campbell (d) Ritter, William Francis McKnight. Robinson, Thomas Rodgers, Christopher Raymond Perry (a). Rodgers, John (d) Rogers, Joseph Addison (a) Russell, Israel Cook Russell, Thomas Salmon, Daniel Elmer Sampson, William Thomas (a).... Sands, Benjamin Franklin (d).... Saville, James Hamilton Schaeffer, George Christian (d). Schott, Charles Anthony Searle, Henry Robinson (d)... Seymour, George Dudley (r)., Shellabarger, Samuel Sherman, John Sherman, William Teccmseh (?-). Shufeldt, Robert Wilson (a) Sicard, Montgomery (a)... Sigsbee, Charles Dwight.. Skinner, John Oscar Smiley, Charles Wesley... Smith, David.. Smith, Edwin. Spofford, Ainsworth Rand. Smithsonian Institution Ave. N. W. 1622 Mass. Army Signal Office Geological Survey. 1221 O St. N. W.. 732 17th St Geological Survey. 1505 Q St. N. W.. Smithsonian Inst. 1214 Va. Av. S. W. Agricultural Department. 1700 13th St. N. W. Nautical Almanac Office. 16 Grant Place. Howard University. 6th St. N. W., cor. Lincoln. 1723 I St. N. W Naval Observatory Geological Survey. 1424 Corcoran St Army Signal Office. 1116 M. St. N. W Agricultural Dept, 1006 N St. N. W... Torpedo Station, Newport, R. I 342 D St. N. W. 1315 M St. N. W. Coast and Geodetic Survey Office. 212 1st St. S. E. Room 23 Corcoran Building. 812 17th St. N. W. 1319 K St. N. W Surgeon Genl's Office, U. S. A., or Box 144 Smithsonian Institution. Ordnance Bureau, Navy Department. Naval Academy, Annapolis, Md 1529 O St. N. W U. S. Fish Commission, 1443 Mass. Ave. 943 Mass. Ave. 1330 Corcoran St Coast and Geodetic Survey Office. 2024 Hillyer Place. Library of Congress. 1621 Mass. Ave. N. W. 1871, Mar. 13 1871, Mar. 13 1871, 1871. 1871, 1877, 1874, 1871, 1871, 1873, 1881. 1873, 1884, 1882, 1874, 1874, 1880, 1879, 1874, 1N8'_\ Mar. 13 May 13 Nov. 17 May 19 Apr. 11 Mar. 13 Mar. 13 Mar. 1 Feb. 19 Oct. 4 De<\ 20 Dec. 16 Apr. 11 Jan. 17 Jan. 3 Mar. 29 Jan. 17 Oct. 7 1884, Jan. 5 1883, Feb. 24 1882, Oct. 7 1884, Feb. 16 1874, Jan. 31 1878, Nov. 9 1877, May 19 1879, Oct. 21 1884, Jan. 19 1872, Mar. 9 1872, Nov. 16 1872, Mar. 9 1882, Mar. 25 1883, Feb. 10 1883, Nov. 24 1883, Mar. 24 1871, Mar. 13 1871, Apr. 29 1871, Mar. 13 1871, Mar. 13 1877, Dec. 21 1881, Dec. 3 1875, Apr. 10 1874, Jan. 17 1871, Mar. 13 1881, Nov. 5 1877, Feb. 24 1S79, Mar. 1 1883, Mar. 24 1882, Oct. 7 1876, Dec. 2 1880, Oct. 23 1S72, Jan. 27 LIST OF MEMBERS. XXI NAME. Stearns, John (a)... Stearns, Robert Edwards Carter. Stone, Ormond (a) , Taylor, Frederick William (a). Taylor, William Bower Thompson, Almon Harris .. Thompson, Gilbert Tilden, William Calvin (a).. Todd, David Peck (a) Toner, Joseph Meredith True, Frederick William.... Twining, William J. (d) Upton, Jacob Kendrick (r). Upton, William Wirt Upton, Winslow (a)., Vasey, George (r).... Walcott, Charles Doolittle... Waldo, Frank (a) Walker, Francis Amasa (a).. Walling, Henry Francis (a). Ward, Lester Frank Webster, Albert Dowry (a). Welling, James Clarke Wheeler, George M. («).... Wheeler, Junius H. (a) .... White, Charles Abiathar... White, Charles Henry White, Zebulon Lewis (a). Williams, Albert, Jr Wilson, Allen D. (<) Wilson, James Ormond. P. O. Address and Residence. Winlock, William Crawford Wolcott, Christopher Columbus (r). Wood, Joseph (a) Wood, William Maxwell (a) Woodruff, Thomas Maher.... Boston, Mass Smithsonian Institution. 122G Mass. Ave. N. W. Leander McCormick Observatory, University of Virginia. .Smithsonian Institution. Lake Val- ley, New Mex. Smithsonian Inst. 306 C St. N. W Geological Survey Geological Survey. 1448 Q St. N. W„ New York City... Lawrence Observ., Amherst, Mass.... 615 Louisiana Ave National Museum , 2d Comptrollers Office, Treasury Dept. 1746 M St. N. W. Blown University, Providence, R. I.. Geological Survey, Nat. Museum Army Signal Office. Ft. Myer, Va.... Mass. Inst, of Technology, Boston, Mass. Geological Survey, Cambridge, Mass, Geological Survey. 1464 R. I. Ave. N. W. West New Brighton, Staten Island, N. Y. 1302 Connecticut Ave Engineer Bureau, War Department.. Lenoir, N. C Geological Survey. Le Droit Park.... 1744 G St. N. W Providence, Rhode Island Geological Survey. 23 Lafayette Square. Franklin School Buiiding. 1439 Mass. Ave. N. W. Naval Observatory. 723 20th St. N.W Woodward, Joseph Janvier (

_y A (it ± i>)_y = A it_y Al)_y+f sin it_y COS it_y sin V—y COS i>_y -f- 1 — f' sin 2it_y sin v—y (7) We have sin (± _J) = ± 1 cos (± J) = A (± J) - fi (8) therefore, replacing v by _Jy, we have COS U-y A it_y sin u—y sin (tt ± _Jy) = cos (it ± _Jy) = dz /5 ' A (it ± _\y) = A U—y (9)A W_y Replacing in these it by it d= _]y, we have sin (u ± 2 ]y) = — sin u—y COS (it ± 2 \y) = — COS U—y A (l* ± 2 _Jy) = A 1t_y (10) It follows, replacing in these it by it -}- 2 |y, that 4 _]y is the complete period of the elliptic sine and cosine and 2 \y that of the delta. Placing u = v, we have the duplication formulae : sin (2m) —y = 2 sin u—y cos u-y a w_y -e- 1 — y2 sin 4W_y COS (2lt) _y = COS 2M_y— sin 2W_y A 2it_y ~- 1 y2 sin *U—y A (2it) _y = a 2w_y— y 2 sin 2it_y cos 2it_y -f- 1 — f~ sin Hl—y (11) Replacing in these u by £ it and solving, we have the dimidia- tion formulae : sin2 f -jj- J -y = 1 — COS U-y -r- 1 + A W_y COS2 (-^-J_y = A 1«_y -f" COS it_y -r- 1 -J- A it_ y A 2 (jA-Y = A2 + A it_y+ y2 COSit_y -fl + A it_y (12) MATHEMATICAL SECTION. 105 Jacobi's imaginary transformation consists in assuming sin

cos

A<£> "' J l/l— / or 106 PHILOSOPHICAL SOCIETY OF WASHINGTON. therefore, replacing in (16) v by _J/j, we have sin (u ± 1/3 i).Q = — : — v — iH J H y sin u.y A (w db _J/3 i)_/3 = =i= t cot W_y (18) Placing in these w ± _J/3 -i for u, we have sin (rt ± 2 _|/3 i)-y = sin u.y cos (w db 2 _J/3 i)-y = — COS U.y i(«±2J i)-7 = — A u.y (19) It follows, replacing in these u by u ± 2 _J/3 i, that 4 _J/3 1 is the imaginary period of the elliptic cosine and delta and 2 _)/3 i that of the sine. We have then, if m and fi are integers, sin (u -\- 4 m _Jy + 2 // _J/3 i)-7 = sin w-7 cos (u + 4 m _]y -j- 4 fi _J/3 t)_y = cos w_y a (m + 2 m _\7 + 4 /j _J/3 »)_7 = a «_y (20) The general problem of transformation may be stated thus : Assuming

tan * o Let ? = J then ?'=_]'; 9" — J" . . . . ?<"> = _]<"> and111 1 _ I _ \r / ±_ |W // t I (00) (=^)tanHJ + J(oo))) (39<->) This transformation can be applied also to the more general form : 9 Jdcp —^f (sin 9, cos ', A ", A p", etc., by means of (31), (32), (33), we arrive, after a few transformations, at the form p(») J=/c(4osV> /(C0) „ — ft) = -1 tan ?, (42x) We have then — „>. The limiting form of the integral is S d. (-1: ^44(0O)) i i If p = J then i ?, = -^ <"<->> This remarkable value for the complete integral was discovered by Gauss by means of a different transformation, known as Gauss'. This may be deduced as follows : Assume in place of (44(°°)) the following series of relations \*t-\w* - \ to*= • • • • h (W° (= k ** (44 "} MATHEMATICAL SECTION. Ill To discover the relations for the first step we have to determine ,)yv then & u = (^)n and u.7l = ?y ;^ J _7l = ^1? and consequently sin V'i = 1 — cos ^ -f- 1 + A ) ( Woo -"i to/n-^to)*- -£(*->• ( = ^ 0. (52y) -j-^ — ^(ft)A"^to)A- =^ (^^ ( = r-/tan £ (J + 9») Woo -s; fr-o^-yyCfJr.- =^ lim ^r ( c(°°) ^ 4w = i-^v= =^)<".( "'a ^ a ( =^(oo) (52/3) i i p > L i" " — - I (»> MATHEMATICAL SECTION. 113 ( = ^tani(J + JO) ( = r-/tani(J+ J.)Woo —^JflT-^J^- =^J (53/5) We easily deduce the symmetrical relations ?1(») (^X = ^oo 0(») (54) Ji (fle) (J-)i« J2 (55) This last equation is well known ; it appears here, however, as a particular case of a more general relation. The quantity ^oo is the argument of the functions and then usually denoted x\ ^>1 ( cc ) is v v' then denoted by x' ; Schellbach has -^ for ( loo)! and ~n for I/ 00), while Hoiiel, in his Recueil de Tables, has p and p', respectively. Other relations are yt (x) _ " J "(J-X ^^ (M l (flB) fcOi_^_l fr-V (M^"» i''(oc)2 ™ CJ-X" J ' J ~ -Ji(0O); (J»)i"~ J "J-J ( 7) The following expressions for the nome q can now be given : ? = e -2^J =e -2(J„), The first form is simply Jacobi's definition ; the second gives, S1D.CG (J K) 1 = hanHJ + J») (59) g = cot 2 J (J + Joo) (60) This is one of the best formulas for computing q, especially if the modulus does not differ much from unity. The third form may be 114 PHILOSOPHICAL SOCIETY OF WASHINGTON. used if b and c are not very different, for in that case the algorithm of the arithmetico-geometric mean converges equally fast in both directions. If either b or c is very near to a, the process may con- verge in one direction so slowly that the formula becomes nearly inapplicable. The fourth form may be transformed to a new formula, which is more convenient than any given. In (52/?) place

n + 1 *»*-£) *- ' l/*(«»-6-) (sufficien% near> _. _L j 2 2 y^ gn + t ( sufficiently near) 1 22 a,, = r— / — — (sufficiently near) (62) therefore we have by (61) 1 2~» . 22 an or 6. , /22 a„\2-" r-Jf-'A— ) since cn = £ (a„_i — 6 n_i) = ?£— ii Ctn V C z n-2 / \ C„_2 / if a„_i = i/a„ an-x \ C n-3 / \ C„-3 / if a„_2= y ' an_1 a#j_2 if « 2 = l/ a3 a2 (63) if Cl = T/ a2 ^ (64) 116 PHILOSOPHICAL SOCIETY OF WASHINGTON. Using (63) in the fourth form of (58) we have Cj a— b and using (64) we have « - Gftr)' w The norae of the complementary integral is denoted by Jacobi and writers that follow him by q 1 . In our system this would be the notation for the nome of the integral ) = |^rC= (^) 2 (67) where o(**-1 ) = j/ aW a (n_1 ) a("-2) = j/ « n-i a n~2 a (»—3) = |/ a n-2 a »— 3 = l/ a'" a" «' = i/ «" of (68) By (55) and the second forms of (58) and (67) we have the following relation between p and q lp-'Alq-y2=_f (69) or in Briggian logarithms log { log p-V* log q-y*}= log (J log ej = 9.6678084 (69') or logjlogp"1 log q-1 }= 0.2698684 (70) By means of this relation we can always choose the shortest route to either p or q. It is easy to see that the nomes and com- MATHEMATICAL SECTION. 117 plementary nomes at the several steps of the modular scale are as follows 2—2 2~1 <7n 2-n q =q; tf = n = i> 2" ^ ; p x =tf \ p=p; p =p*;p" 2-2 _M .2-» i? j)<") = j>" (72) We have then in this transformation the simplest possible case of Abel's theorem (27) ; and because in ascending we pass to the square of the nome, it is called the quadric transformation. The ascending transformation is possible in real quantities if c > a, for we have M{c, a) = M(a, c). Also if b > a we can use the descending transformation ; and in either case we can, after one transformation, proceed in either direction. This may be symbolized by the following diagram V > e" « 118 PHILOSOPHICAL SOCIETY OF WASHINGTON. CO CO MATHEMATICAL SECTION. 119 T3 O be 120 PHILOSOPHICAL SOCIETY OF WASHINGTON. GO a o to O o be .3 1=1 bO t—I CO -+1 o CO CO OS os OO H co ia o OS O . 03 *» ' bC - o S>- bfl o oO GO o os'O iO o -*O O) oO iO t- CO &- s- o MATHEMATICAL SECTION. 121 H3 p y* I'l'l PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. Hall spoke of the importance of the arithmetico-geometric mean in astronomy. Mr. W. B. Taylor made a communication on A CASIO OF DISCONTINUITY IN ELLIPTIC ORBITS ' around an empty center of gravitative force. Diminution of the minor axis of the attracted hody's path (the major axis being con- stant) increases the ratio of distance at the two apses without limit, the "periapsis" continually approaching the attractive center, as long as the minor axis has a value, however small. But when this axis is made to vanish, and the motion is directly to the center of force, the body, instead of rebounding from it, as continuity would require, will pass through it, and describe an equal path on the opposite side, the orbit being at once doubled. This paper was discussed by Messrs. Bates, Christie, Hall and others, and brought out a wide diversity of view as to the demeanor of a heavy point when coincident with an empty attract- ing center. 15th Meeting. December 3, 1884. The Chairman presided. Nineteen members and guests present. Mr. M. H. DOOLITTLE made a communication on THE VERIFICATION OF PREDICTIONS. [Abstract.] Mr. G. K. Gilbert has published (American Meteorological Journal, 8°, Detroit; September, 1884, pp. 160-172) a method of estimating the ratio of skill in predictions of occurrences and non- occurrences of a simple event. Adopting his notation, we have 8 = the sum or total number of cases, o = the number of occurrences, p = the number of predictions of occurrences, MATHEMATICAL SECTION. 123 c = the number of coincidences or verifications, i = the inference-ratio, or that part of the success which is due to skill and not to chance, and which may be called the degree of logical connection between event and prediction. Since success is proportional to each of the two fractions — and — > o p it may be represented by their product c?_ op' The fraction — represents the ratio of random success, and op therefore — verifications out of p predictions are to be ascribed to chance and must be subtracted throughout. The remainders, op . op o — — and p — — » S r 8 represent fields which chance leaves for science to conquer ; and op c — — s represents the portion of each which science does conquer. Hence op op . £_ ^ * . Q — op)2 l ~ -?p v -?p == oP(s-oXs-py s F s By another method, — = the probability that any single occurrence will be predicted in some manner. *—^2— = the probability that any single date of non-occurrence will correspond to an unsuccessful prediction = the general probability of unskillful prediction in any case. Subtract from the probability that any single occurrence will be predicted in some manner the general probability of unskillful prediction, and we have = the probability that any given occurrence will be skillfully predicted. 124 PHILOSOPHICAL SOCIETY OF WASHINGTON. In like manner — = the probability that any single prediction will be fulfilled in some manner. "~— c = the general probability of unpredicted occurrence; which, in case of prediction, becomes probability of fortuitous ful- fillment. (* Q mmmm f = the probability that any single prediction will be fulfilled by reason of a logical connection. Since the skillful predictions are mingled indistinguishably with all the unskillful ones, and are vitiated accordingly, the value of the vitiated probability of the skillful prediction of any single occurrence may be represented by the product f c p — c\ f c o — c\ (cs — op) 2 \ o ~ s — o) \p ~~ s— p) ~ op(s — o){8 — p)' as before. Prof. C. S. Peirce (in Science, 1884, Nov. 14, Vol. IV, page 453) deduces the first of these factors as the unqualified value of i, making no allowance for the vitiation, and tacitly assuming that an assortment of predictions is the logical equivalent of a jumble of the same predictions. He obtains his result by the aid of the supposition that part of the predictions are made by an infallible prophet, and the others by a man ignorant of the future. If Prof. Peirce had called on omnipotence instead of omniscience, and sup- posed the predictions to have been obtained from a Djinn careful to fulfill a portion of them corresponding to the data, the remainder of the occurrences being produced by an unknown Djinn at ran- dom, he would have obtained by parallel reasoning the second — — —^— J . These Djinns represent, respectively, the known and unknown forces of nature, and gauge the prophet's knowledge with principal reference to the proportion of predictions fulfilled. Prof. Peirce's test refers principally to the proportion of occurrences predicted. His test eliminates sins of omission ; the other, sins of commission ; and both are necessary to a proper estimate of the prophet's comparative rectitude. MATHEMATICAL SECTION. 125 In the data cited by Mr. Gilbert from Finley's tornado predic- tions, s = 2803, o = 51, p = 100, and c = 28. By Mr. Gilbert's formula, cs — op A H — — 8 (° + p — c) -• °p he obtains Prof. Peirce obtains I obtain i = .216. i = .523. i = .142. By making 8, o, and i constant, and imposing conditions on p and c, we may obtain hypothetical data involving equal skill. Putting c = p, I infer that Mr. Finley would have manifested equal skill if he had made no false predictions of tornadoes, and, out of the 51, had predicted 7.35. Mr. Gilbert's formula gives 11.18, and Prof Peirce's 26.67. Putting c = o, I infer that he would also have manifested equal skill if he had included all the 51 tornadoes by making 323.7 predictions. Mr. Gilbert's formula gives 221.5, and Prof. Peirce's 1364. Mr. Finley's entire success in predicting tornadoes is — =.154; op ' and since the portion due to skill = .142, we may infer that .923 of this success is due to skill, and only .077 to chance. On the other hand, of his success in predicting the non-occurrence of tor- nadoes, only .147 is due to skill, and .853 is due to chance. Prophecy and fulfillment are effects of a common cause. Neither causes the other. The problem, broadly stated, requires a nume- rical expression for the causal relation between two classes of phe- nomena either in co-existence or in sequence, when the presence of one corresponds sometimes to the presence and sometimes to the absence of the other, and sometimes both are absent. In case of sequence it is immaterial which is antecedent. The quantities de- noted by o and p should therefore be interchangeable. My formula responds properly to every test proposed by Mr. Gilbert. The value of i increases rapidly with that of c, and 126 PHILOSOPHICAL SOCIETY OF WASHINGTON. slowly with that of s, diminishes with increase of o or p, and varies between the limits and 1. Skill in making false predictions is indicated by a negative value of cs — op; but the same degree of causal relation exists as when equal skill is employed in making true predictions ; and a negative value of i can never occur. When s = either p or o, i = -rp but the apparent indeterminateness van- ishes when we consider that i is the product of two factors, of which one = and the other is indeterminate within limits. And the value of i is unaltered when predictions of non-occurrences are substituted for those of occurrences, and vice versa. In the latter case, write s — o for o, s — p for p, and s — o — p + c for c ; and the formula reduces to its original form. In addition to Mr. Gilbert's tests, two others may be considered. In the case of predictions all falsely reported, we may write s — p for p and o — c for c ; and the formula becomes (op — cs) 2 op (s — o) (s — py with a proper reversal of signs in the quantity under the exponent and no change in the value of i. If occurrences always appear whenever they are not predicted, and never appear when they are predicted, we put e — and p= s — o, with the result i= l; or the logical connection is perfect. In order that the general formula shall be properly applicable, care must be taken that the predictions are fairly homogeneous in definiteness of time and space. For illustration : if predictions that phenomena will occur in given months are examined indis- criminately with those that they will occur on given days, the result will be manifestly worthless. It has been proposed to extend the problem so as to include three or more classes of events of which one must happen and only one can happen in any case. It seems clear to me that no single numerical expression can be a proper solution of such a problem. Suppose the three classes of events, A, B, and C. By the method above given A and Not A may be examined ; and all instances MATHEMATICAL SECTION. 127 involving either the prediction or occurrence of A may be excluded and B and C separately investigated. Suppose it thus ascertained that great skill has been shown in discriminating between A and Not A, and little or none in discriminating between B and C. No single numerical expression can properly comprehend these heter- ogeneous results. Mr. Curtis showed that some of the results given by Mr. Doo- little could be independently deduced by another method. Mr. Gilbert noted as a defect in the formula proposed by Prof. Peirce, that it did not duly discourage positive predictions of rare events ; and, while gratified with Mr. Doolittle's discussion of the subject, he expressed a disappointment that no satisfactory decision as to the treatment of cases of three or more alternatives had been reached by him. After some further discussion, a communication by Mr. M. Baker was called, but postponed, on motion of Mr. H. Farquhar, to allow time for the consideration of a testimonial to a late asso- ciate, Mr. Alvord. Mr. E. B. Elliott read the following tribute, prepared by Mr. Baker and himself: MEMOEIAL. The Mathematical Section of the Philosophical Society of Wash- ington, having suffered the loss by death, on October 16th, 1884, of General Benjamin Alvord, one of its founders and active workers, desires to place on record this testimonial to his worth and to the loss to this Section and to science by his death. Of his worth, one of America's greatest mathematicians has said that he was a scientist of " real originality who had actually ex- tended the boundaries of science." The bent of General Alvord's mind and studies was early directed towards a purely geometrical solution of the general prob- lem of tangencies, and his reward, which it is our pleasure to chronicle, was success. Of his mathematical publications, the following is submitted as a provisionally complete list : 128 PHILOSOPHICAL SOCIETY OF WASHINGTON. LIST OF MATHEMATICAL PUBLICATIONS BY GENERAL BENJAMIN ALVORD. 1. The tangencies of circles and of spheres. [In Smithsonian Contributions to Knowledge. 4°. Wash- ington, 1856, Vol. 8, Article 4, 16 pp., 9 plates.] Also issued separately. 2. On the interpretation of imaginary roots in questions of maxima and minima. [In The Mathematical Monthly. 4°. New York, 1860, April, Vol. 2, No. 7, pp. 237-240.] 3. Tangencies. [In Johnson's New Universal Cyclopaedia. 8°. New York, 1878, Vol. 4, pp. 723-4.] 4. Mortality in each year among the officers of the army for fifty years, from 1824 to 1873, as derived from the army registers. [In Proceedings of the American Association for the Ad- vancement of Science, 23d Meeting, Hartford, August, 1874. 8°. Salem, 1875, pp. 57-59.] 5. The intersection of circles and the intersection of spheres. [In American Journal of Mathematics. 4°. Baltimore, 1882, March, Vol. 5, No. 1, pp. 25-44; 4 plates.] 6. Curious fallacy as to the theory of gravitation. [In Bulletin of the Philosophical Society of Washington. 8°. Washington, 1883, Vol. 5, pp. 85-88.] 7. A special case in maxima and minima. [In Bulletin of the Philosophical Society of Washington. 8°. Washington, 1884, Vol. 6, p. 149.] Mr. M. Baker, in moving the adoption of this memorial by the Section, said : General Alvord's entire life was that of the soldier, and his routine of life work did not call him in the direction of mathemati- cal study. Hence whatever he accomplished in mathematics or literature was accomplished in military surroundings and with only such facilities as barrack and camp life afford. If under these MATHEMATICAL SECTION. 129 conditions the total of his contributions to science appears small, we should bear in mind that any contribution under such circum- stances is exceptional. And to have been able, therefore, to make even a single contribution to human knowledge is to have done that which few men in any generation do aud that of which any one of us might well be proud. General Alvord early became interested in the problem of tan- gencies and intersections of circles, and his chief mathematical work and fame rests on his complete and purely geometrical solu- tion of the various problems relating to this subject. His chief writings on this subject consist of the paper on Tangencies, in the Smithsonian Contributions in 1856 ; the article on Tangencies, in Johnson's New Universal Cyclopaedia ; and the paper on intersec- tions, in the American Journal of Mathematics, March, 1882. The memorial was adopted, and the Secretary was instructed to send a copy of it to the family of the deceased. Note. The following members have assisted the Chairman and Secre- tary in the examination of abstracts of communications to the Mathematical Section : Title. Author. Third Member. The Problem of the Knight's Tour. G. K. Gilbert. E. B. Elliott. Formulas for Diminution of Ampli- tude of a Pendulum H. Farquhae. A. S. Christie. The Formulas for Computing the Position of a Satellite A. Hall. C. H. Kummell. The Quadric Transformation of El- liptic Integrals C. H. Kummell. G. W. Hill. The Verification of Predictions M. H. Doolittlb. M. Baker, INDEX. Page. Abbe, Cleveland : remarks on deflection of rivers 23 — report as Treasurer xxiv Address of the President xxix, 81 Alaska river mouths 24 Alvord, Gen. Benjamin, Death of 72 — Memorial to 127 Antisell, Thomas: remarks on the chemical elements 16 pumice 20, 26 Annual address xxix, 81 — meeting 81 Application of physical methods to intellec- tual science 18 Are there separate centres for lipht- form- and color-perception? 72 Aristotle, cited on atoms xxxii Atomic philosophy 40 The, physical and metaphysical. ...xxix, 81 Auditing committee, Appointment of. 82 Report of 15 Babcock, Gen. O. E., Death of. 72 Bacon, cited on atoms xli Baker, Blarcus: memorial to General Alvord.. 127 Barnard, W. S., Election to membership of.. 25 Bates, H. H. : communication on the physi- cal basis of phenomena 40 Bean, T. H., Election to membership of. 72 Bibliography of North American geology 71 mathematical papers by Benjamin Al- vord 128 Billings, J. S.: communication on compos- ite photography applied to craniology... 25 — exhibition of microscopes 73 — remarks on bibliography 72 — resolutions on the death of Dr. Wood- ward 75 Blair, H. \V., Death of. 81 — Election to membership of. 15 Bog-isloff, Volcanic dust from 34 Bout.elle, C. E., Election to membership of... 18 — remarks on the deflection of rivers 24 Bowles, F. T., Election to membership of..... 26 Boyle, Robert, cited on atoms xlvi Brown, S. J., Election to membership of 72 Browne, W. R., cited on matter 31 Bulletin of the General Meeting 1, 3 Mathematical Section 83, 87 — Rules for publication of xiii Page. Buoys drifted by ocean currents 14 Burchard, H. C. : remarks on the irrigation of the upper Missouri valley 20 Burnett, S. M. : communication on separate centres for light- form- and color-percep- tion 72 Why the eyes of animals shine in the dark 13 Calendar xxii Case of discontinuity in elliptic orbits 122 Chamberlin, T. C. : communication on What is a glacier? 38 Chatard, T. M. : analysis of andesite 33 Chemical elements and music 27 Periodic law of 15 Cheyne, Dr. George, cited on heredity lv Christie, A. S.: communication on a form of the multinominal theorem 101 Clarke, F. W.: communication on the peri- odic law of chemical elements.. 15 — election to Genera! Committee 36 Clerk-Maxwell, James, cited on properties of matter 44, 47 vortex rings Hv Clifford, Prof., cited on mind-stuff. liii Columbian University affords the Society facilities 80,81 Committee, Auditing 15, 82 — on communications, Duties of xii, 85 Membership of xiv, xv publications, Duties of. xiii Membership of. xiv, xv Committees, Standing xii, xiv, xv Composite photography applied to craniolo- gy 25 Concrete problem in hydrostatics 92, 101 Constitution vii Continents, Forms of 24 Craniology 25 Curtis, G. E : communication on the rela- tions between northers and magnetic disturbances at Havana 25 — election to membership 5 — remarks on the verification of predic- tions 127 Curves similar to their evolutes 87 Dall, W. H. : communication on certain ap- pendages of the mollusca 32 131 132 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Dall, W. H. : recent advances in our knowl- edge of the limpets 4 What is a glacier ? 38 — remarks on Alaskan volcanoes 34 deflection of rivers 24 drifting of buoys 16 tornadoes 3 Dalton, John, contribution to atomic the- ory xlvii, 1, lvi Darwin, cited on gemmules liii Death of Gen. Benjamin Alvord 72, 127 Gen. O. E. Babcock 72 H. W. Blair 81 Gen. Chas. Ewing xxiii Gen. A. A. Humphreys 3, 4 Dr. J. J. Woodward 72 Resolutions concerning 75 Deceased members, List of. xxiii Deflection of rivers 21 Deposits of volcanic dust in the Great Basin. 18 Dewey, P. P., Election to membership of..... 36 DiKer, J. S. : communication on the volcanic sand which fell at UnalashkaOct. 20,1883, and some considerations concerning its composition .33, 35 — Election to membership of 21 Discontinuity in elliptic orbits 122 Discussion of a concrete problem in hydro- statics proposed by Mr. G. K. Gilbert.-... 101 Diversion of water-courses by the rotation of the earth 21 Doolittle, M. H.: communication on the verification of predictions 122 music and the chemical elements.... 27 Dust, Volcanic 18,33 Dutton, C. E. : communication on the volca- noes and lava fields of New Mexico 76 What is a glacier? 39 — remarks on the forms of continents 24 Navajos as scientific observers 74 r petrography 36 sun-glows 35 Earll, R. E., Election to membership of 72 Earthquake of Sept. 19 73 Eastman, J. R. : communication on a new meteorite 32 the Rochester (Minn ) tornado 3 Eimbeck, William, Election to membership of 26 Election of officers 82, 87 new members.... xi, 5, 10, 15, 18, 21, 25, 26, 32 36, 72, 81 Electric lighting 80 Elements, Periodic law of. 15 Elliott, E. B. : calendar for the use of the society xxii Page. Elliott, E. B.: communication on electric lighting 80 — memorial to General Alvord 127 — remarks on the euharmonic organ 28 irrigation of the upper Missouri valley 20 sun-glows 17 tornadoes 3 Emmons, S. P.: communication on What is a glacier? 37 — remarks on glaciers 9 Empirical formulae for the diminution of amplitude of a freely-oscillating pendu- lum 89 Entomology, Economic 10 Euharmonic organ 28 Ewing, Charles, Death of. xxiii Existing glaciers of the High Sierra of Cali- fornia 5 Eyes of animals, why they shine in the dark 13 Faraday cited on the nature of matter 47 Farquhar, Edward : remarks on ocean cur- rents 24 tornadoes 3 the late Dr. Woodward 76 Farquhar, Henry: communication on em- pirical formulae for the diminution of amplitude of a freely-oscillating pendu- lum 89 the theoretical discussion in Prof. P. G.Tait's Encyclopaedia Britannica article on mechanics 29 — election as Secretary of the Mathemati- cal Section 87 — remarks on drifting of buoys 15 — report as Secretary xxiii Ferrel, William, cited on rotational deflec- tion 22 Finley's tornado predictions 125 Fisheries exhibitions 26 Force, Reality of 30 Form of the multinominal theorem 101 Formula for the length of a seconds-pen- dulum 101 Formulae for computing the position of a satellite 93 General Meeting, Bulletin of 1, 3 Geological section of water-works shaft 69, 70 Gihon, A. L. : remarks on the late Dr. J. J. Woodward 76 Gilbert, G. K. : communication on a concrete problem in hydrostatics 92 the diversion of water-courses by the rotation of the earth 21 INDEX. 133 Gilbert, G. K. : a plan for the subject biblio- graphy of North American geologic lite- rature 71 the problem of the knight's tour 88 — remarks on the origin of pumice 25 upper Missouri valley 20 verification of predictions 127 — report as secretary xxiii Glacier tables 7 Glacier, What is a 37 Glaciers of the Coast Range 8 High Sierra 5 Rocky Mountains 8 Goode, G. Brown: communication on fish- eries exhibitions 26 Gregory, J. M., Election to membership of... 26 Hall, Asaph : communication on the form- ulae for computing the position of a satellite 93 — election as chairman of the Mathemati- cal Section 87 — remarks on the arithmetico-geometric mean 122 Harkness, William : remarks on glaciers 9 the shining of eyes in the dark 13 Hazen, H. A.: communication on the sun- glows 17 thermometer exposure 80 — remarks on the deflection of rivers 24 Heap, D. P., Election to membership of. 32 High Sierra, Glaciers of 5 Hill, G. W. : communication on a formula for the length of a seconds-pendulum... 101 Hitchcock, Prof. C. H 4 Hitchcock, Romyn, Election to membership of 36 Holmes, W. H. : remarks on glaciers 8 Humphreys, A. A., Death of. 3, 4 Ice pyramid 6, 7 Indians, Observation and generalization by. 73 Insecticides 10 Integrals, Transformation of elliptic 102 Intrinsic equation 87 Irrigation of the upper Missouri valley 20 Jenkins, T. A.: remarks on drifting of buoys 15 Johnson, A. B. : communication on some eccentricities of ocean currents 14 Johnson, W. D., Election to membership of... 18 Kauffmann, S. H., Election to membership of 21 Kerr, W. C. : communication on the mica mines of North Carolina 9 27 Page. Kerr, M. B., Election to membership of. 21 — remarks on glaciers 8 Knight's tour 88 Knox, J. J. : resignation from General Com- mittee 36 Kummell, C. H. : communication on curves similar to their evolutes 87 the quadric transformation of ellip- tic integrals, combined with the algo- rithm of the arithmetieo-geometrical mean 102 — remarks on musical intervals 28 Lake Bonneville 92 Lawrence, William, Election to member- ship of. 21 Lefavour, E. B. : remarks on musical scales. 28 Leibnitz, cited on atoms xliii Limpets 4 McGee, W J : communication on What is a glacier ? 38 Maher, J. A.: Election to membership of 26 Marcou, J. B., Election to membership of.... 26 Martin, Artemas: letter to Mathematical Section 87 Mason, O. T. : remarks on the conditions of observation 74 Mathematical Section, Bulletin of 83, 87 Members of 86 Officers of. 86, 87 — society proposed 87 Matthews, Washington : communication on natural naturalists 73 — election to membership 72 Members, List of xvi deceased, xxiii new '. xxiii — of Mathematical Section 86 Memorial to General Alvord 127 Merrill, G. P., Election to membership of.... 36 Meteorite 32 Methods of modern petrography 36 Mica mines of North Carolina 9 More, Henry, cited on nature of matter xlii Mount Taylor, Geology of. 77 Muir, John, cited on glaciers 8 Murdoch, John, Election to membership of. 36 Music and the chemical elements 27 Mussey, R. D. : communication on the appli- cation of physical methods to intellec- tual science .'. 18 — remarks on the forms of continents 24 Natural naturalists 73 Necks, Volcanic 78 Neve denned 37 134 PHILOSOPHICAL SOCIETY OP WASHINGTON. Page. New members xxiii — meteorite 32 — Mexico, Volcanoes of. 76 Newton, cited on atoms xliv Norris, Basil, Election to membership of 25 North Carolina, Mica mines of 9 Ocean currents 14 Officers, Election of 82, 87 — List of. xiv, xv — of the Mathematical Section 85, 86, 87 Ogden, H. G., Election to membership of..... 15 Paul, H. M. : remarks on earthquakes 73 equipotential surfaces 92 sun-glows 35 Peirce, Prof. Benjamin, cited on the intrinsic equation 87 Peirce, C. S., cited on pendulum observa- tions 90 the verification of predictions 124 Pendulum, Formula for diminution of am- plitude of oscillation of. 89 Periodic law of chemical elements 15 Petrographic methods 36 Physical basis of phenomena 40 — and economic features of the upper Mis- souri system 20 Plan for the subject bibliography of North American geologic literature 71 Plateau country 76, 79 Powell, J. W. : communication on a plan for the subject bibliography of North Amer- ican geologic literature 71 — remarks on the distribution of eruptions. 79 glaciers 8 the history of the society 81 late Dr. Woodward 76 Predictions, Verification of 122 Presidential address xxix Problem of the knight's tour 88 Pumice, Formation of. 20, 25, 26 Quadric transformation of elliptic integrals, combined with the algorithm of the arithmetico-geometric mean 102 Ray, P. H., Election to membership of 5 Recent advances in economic entomology... 10 our knowledge of the limpets 4 Relation between northers and magnetic disturbances at Havana 25 Report of secretaries xxiii, 82 treasurer xxiv, 15,82 Review of the theoretical discussion of Prof. P. G. Tait's Encyclepaedia Britannica article on mechanics 29 Page. Ricksecker, Eugene, Election to member- ship of. 18 Riley, C. V.: communication on recent ad- vances in economic entomology 10 — remarks on the irrigation of the upper Missouri valley 20 Rivers, deflection of 21 Robinson, Thomas : communication entitled Was the earthquake of Sept. 19 felt in the District of Columbia? 73 on the strata exposed in the east shaft of the water-works extension 69 — election to membership 10 — remarks on the deflection of rivers 24 Rochester (Minn.) tornado 3 Rotation and rivers 21 Rules for the publication of the Bulletin.... xiii — of the General Committee xii Mathematical Section 85 Society ix Russell, I. C. : communication on deposits of volcanic dust in the Great Basin 18 the existing glaciers of the High Sierra of California 5 What is a glacier? 37 Sand, Volcanic 33 Satellite, Computation of position of a 93 Scales, Musical 27 Secretaries' report xxiii, 82 Sierra Nevada glaciers 5 Some eccentricities of ocean currents 14 Standing rules of the General Committee xii Mathematical Section 85 Society ix Stearns, R. E. C, Election to membership of. 81 Strata exposed in the east shaft of the water-works extension, 69 Sun-glows 17, 35 Tait, Prof. P. G., on mechanics ; reviewed.... 29 Taylor, F. W. : analysis of meteorite 32 Taylor, W. B. : communication on a case of discontinuity in elliptic orbits 122 — remarks on sun-glows 35 Thermometer exposure 80 Thompson, Gilbert, Election to member- ship of. 18 — remarks on glaciers 8 Toner, J. M. : remarks on the late Dr. Wood- ward ?6 Tornado at Rochester (Minn.) 3 Treasurer's report xxiv, 15, 82 Verification of predictions 122 Volcanic dust 18,33 INDEX. 135 Ward, L. F. : communication on some phys- ical and economic features of the upper Missouri system 20 — remarks on the deflection of rivers 23 Indians as botanic observers 74 Was the earthquake of Sept. 19 felt in the District of Columbia? 73 Welling, J. C. : eulogy on Gen. Humphreys.. 4 — presidential address xxix, 81 — remarks on drifting of buoys 15 the Indian as a scientific observer... 75 Williams, G.H. : communication on methods of modern petrography 36 What is a glacier? 37 Page. White, C. H., Election to membership of..... 21 White, C. A. : report of auditing committee. 15 Why the eyes of animals shine in the dark 13 Woodruff, T. M., Election to membership of 32 Woodward, Dr. J. J., Death of. 72 — Resolutions on death of 75 Woodward, R. S.: discussion of a concrete problem in hydrostatics proposed by Mr. G. K. Gilbert 101 — remarks on deflection of plumb-line 92 Yeates, W. S., Election to membership of.... 36 BULLETIN OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. VOL. VIII. Containing the Minutes of the Society and of the Mathematical Section for the year 1885. PUBLISHED BY THE CO-OPERATION OF THE SMITHSONIAN INSTITUTION. WASHINGTON : 1885 CONTENTS. Page. Constitution vil Standing Rules of the Society ix Standing Rules of the General Committee xn Rules for the Publication of the Bulletin xiii Officers elected December, 1884 xiv Officers elected December, 1885 xv List of Members xvi List of deceased members xxv Annual Report of the Secretaries • xxyii Annual Report of the Treasurer xxviii Calendar xxx Annual Address of the President, Asaph Hall xxxin Bulletin of the General Meeting 1 Report of the Auditing Committee 3 The vital statistics of the Tenth U. S. Cerisus, J. S. Billings, (Title only) 4 Recent experiments on reaction time and the time sense, G. Stanley Hall, (Title only) 4 Practical geology versus speculative physics, C. E. Dutton, (Title only) 4, 5 Topaz from Stoneham, Maine, F. W. Clarke and J. S. Diller, (Titleonly) 5 Two remarkable forms of mollusks, W. H. Dall 5 Geological and physical theories, "W. B. Taylor 6 Methods of verifying weather predictions, C. Abbe 8 Variations of latitude, A. Hall _. 10 Thunderstorms of 1884, H. A. Hazen 10 The Javal and Schiotz ophthalmometer, S. M. Burnett, (Title only) 11 The difficulty in determining the direction of sound, A. B. Johnson 11, 12 Mythological dry painting of the Navajos, W. Matthews 14 Comets II and III, 1884, W. C. Winlock 16 Problems connected with the physics of the earth's crust, H. M. Paul, (Titleonly) 17, 18 Modern ideas of brain mechanism, F. Baker, (Title o?ily) 17 The flora of the Laramie group, L. F. Ward, (Title only) 17 The measurement of temperature at distant points, T. C. Men- hall, (Titleonly) 18 The asteroids, G. L. Ravene, (Title only) 18 III IV CONTENTS. Page. The mechanism of "clicks" and "clucks," A. G. Bell, {Title only) «.. 18 The crumpling of the earth's crust, W. B. Taylor. 18 The columnar structure in the diahase of Orange mountain, N. J., J. P. Iddings 19 The terraces of the Potomac valley, W J McGee, [Title only). 24 Anthropometric and reaction-time apparatus, J. S. Billings and W. Matthews 25 The condensing hygrometer and sling psychrometer, H. A. Hazen 25 A new volt-meter, T. C. Mendenhall 26 Flextures of transit instruments, W. Harkness 27 An attempt at a theory of odor, F. W. Clarke 27 The Flood Rock explosion, F. W. Clarke, C. F. Marvin, and H. M. Paul 28 The systematic care of pamphlets, G. B. Goode and C. V. Biley 29 Germ cultures, J. S. Billings 30 Presentation of the annual address 30 Annual meeting 30 Bulletin of the Mathematical Section 33 Standing Rules of the Section 35 Officers of the Section 36 Example illustrating the use of a certain symbol in the calcu- lus of affected quantity, E. B. Elliott, (Title only) 37 A collection of formula? for the area of a plane triangle, M. Baker, (Title only) 37 Physical observations on Wolfs comet (1884, III), W. C. Winlock 37 A slight modification of the Newtonian formula of gravitation, W. B. Taylor : 39 An artifice sometimes useful for the adjustment of conditioned observations, C. H. Kummell 41 The theory of Mercury, G. L. Ravene 41 A group of circles related to Feuerbach's circle, M. Baker 45 Distances on any spheroid, C. H. Kummell 52 On Grassman's system of geometry, A. Ziwet 53 Cause and chance in the concurrence of phenomena, M. H. Doolittle, (Title only) 54 The asteroids, G. L. Ravene, (Title only) 54 Secular perturbations of Polyhymnia by Jupiter, W. F. McK. Ritter 54 Some practical features of a field time determination with a meridian transit, R. S. Woodward 55 Can the attraction of a finite mass be infinite ? C. H. Kum- mell 58 Committees on mathematical communications t 68 Index 65 BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. CONSTITUTION, RULES, OFFICERS AND MEMBERS, AND REPORTS OF SECRETARIES AND TREASURER. CONSTITUTION THE PHILOSOPHICAL SOCIETY OF WASHINGTON. Article I. The name of this Society shall be The Philosophi- cal Society of Washington. Article II. The officers of the Society shall be a President, four Vice-Presidents, a Treasurer, and two Secretaries. Article III. There shall be a General Committee, consisting of the officers of the Society and nine other members. Article IV. The officers of the Society and the other members of the General Committee shall be elected annually by ballot ; they shall hold office until their successors are elected, and shall have power to fill vacancies. Article V. It shall be the duty of the General Committee to make rules for the government of the Society, and to transact all its business. Article VI. This constitution shall not be amended except by a three-fourths vote of those present at an annual meeting for the election of officers, and after notice of the proposed change shall have been given in writing at a stated meeting of the Society at least four weeks previously. Yii STANDING RULES FOR THE GOVERNMENT OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON", 1. The Stated Meetings of the Society shall be held at 8 o'clock p. m. on every alternate Saturday ; the place of meeting to be designated by the General Committee. 2. Notice of the time and place of meeting shall be sent to each member by one of the Secretaries. When necessary, Special Meetings may be called by the President. 3. The Annual Meeting for the election of officers shall be the last stated meeting in the month of December. The order of proceedings (which shall be announced by the Chair) shall be as follows : First, the reading of the minutes of the last Annual Meeting. Second, the presentation of the annual reports of the Secretaries, including the announcement of the names of members elected since the last annual meeting. Third, the presentation of the annual report of the Treasurer. Fourth, the announcement of the names of members who, having complied with Section 14 of the Standing Rules, are entitled to vote on the election of officers. Fifth, the election of President. Sixth, the election of four Vice-Presidents. Seventh, the election of Treasurer. Eighth, the election of two Secretaries. Ninth, the election of nine members of the General Committee. Tenth, the consideration of Amendments to the Constitution of the Society, if any such shall have been proposed in accordance with Article VI of the Constitution. Eleventh, the reading of the rough minutes of the meeting. ix X PHILOSOPHICAL SOCIETY OF WASHINGTON. 4. Elections of officers are to be held as follows : In each case nominations shall be made by means of an informal ballot, the result of which shall be announced by the Secretary ; after which the first formal ballot shall be taken. In the ballot for Vice-Presidents, Secretaries, and Members of the General Committee, each voter shall write on one ballot as many names as there are officers to be elected, viz., four on the first ballot for Vice-Presidents, two on the first for Secretaries, and nine on the first for Members of the General Committee ; and on each subse- quent ballot as many names as there are persons yet to be elected and those persons who receive a majority of the votes cast shall be declared elected. If in any case the informal ballot result in giving a majority for any one, it may be declared formal by a majority vote. 5. The Stated Meetings, with the exception of the annual meet- ing, shall be devoted to the consideration and discussion of scientific subjects. The Stated Meeting next preceding the Annual Meeting shall be set apart for the delivery of the President's Annual Address. 6. Sections representing special branches of science may be formed by the General Committee upon the written recommenda- tion of twenty members of the Society. 7. Persons interested in science, who are not residents of the Dis- trict of Columbia, may be present at any meeting of the Society, except the annual meeting, upon invitation of a member. 8. * On request of a member, the President or either of the Secre- taries may, at his discretion, issue to any person a card of invitation to attend a specified meeting. Five cards of invitation to attend a meeting may be issued in blank to the reader of a paper at that meeting. 9. Invitations to attend during three months the meetings of the Society and participate in the discussion of papers, may, by a vote of nine members of the General Committee, be issued to persons nominated by two members. 10. Communications intended for publication under the auspices of the Society shall be submitted in writing to the General Com- mittee for approval. * Amended January 17, 1885. STANDING RULES. XI 11. Any paper read before a Section may be repeated, either entire or by abstract, before a general meeting of the Society, if such repetition is recommended by the General Committee of the Society. 12. *It is not permitted to report the proceedings of the Society or its Sections for publication, except by authority of the General Com- mittee. 13. New members may be proposed in Avriting by three members of the Society for election by the General Committee ; but no per- son shall be admitted to the privileges of membership unless he signifies his acceptance thereof in writing within two months after notification of his election. 14. Each member shall pay annually to the Treasurer the sum of five dollars, and no member whose dues are unpaid shall vote at the annual meeting for the election of officers, or be entitled to a copy of the Bulletin. In the absence of the Treasurer, the Secretary is authorized to receive the dues of members. The names of those two years in arrears shall be dropped from the list of members. Notice of resignation of membership shall be given in writing to the General Committee through the President or one of the Secre- taries. 15. The fiscal year shall terminate with the Annual Meeting. 16. fAny member who is absent from the District of Columbia for more than twelve consecutive months may be excused from pay- ment of dues during the period of his absence, in which case he will not be entitled to receive announcements of meetings or current numbers of the Bulletin. 17. Any member not in arrears may, by the payment of one hundred dollars at any one time, become a life member, and be relieved from all further annual dues and other assessments. All mo,neys received in payment of life membership shall be invested as portions of a permanent fund, which shall be directed solely to the furtherance of such special scientific work as may bo ordered by the General Committee. * Adopted January 17, 1885. f Amended December 19, 1885. STANDING RULES OP THE GENERAL COMMITTEE OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. 1. The President, Vice-Presidents, and Secretaries of the Society shall hold like offices in the General Committee. 2. The President shall have power to call special meetings of the Committee, and to appoint Sub-Committees. 3. The Sub-Committees shall prepare business for the General Committee, and perform such other duties as may be entrusted to them. 4. There shall be two Standing Sub-Committees ; one on Com- munications for the Stated Meetings of the Society, and another on Publications. 5. The General Committee shall meet at half-past seven o'clock on the evening of each Stated Meeting, and by adjournment at other times. 6. For all purposes except for the amendment of the Standing Rules of the Committee or of the Society, and the election of mem- bers, six members of the Committee shall constitute a quorum. 7. The names of proposed new members recommended in con- formity with Section 13 of the Standing Rules of the Society, may be presented at any meeting of the General Committee, but shall lie over for at least four weeks before final action, and the concur- rence of twelve members of the Committee shall be necessary to election. The Secretary of the General Committee shall keep a chronologi- cal register of the elections and acceptances of members. 8. These Standing Rules, and those for the government of the Society, shall be modified only with the consent of a majority of the members of the General Committee. xii IR,TJ31.ES PUBLICATION OF THE BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. 1. The President's annual address shall be published in full. 2. The annual reports of the Secretaries and of the Treasurer shall be published in full. 3. When directed by the General Committee, any communication may be published in full. 4. Abstracts of papers and remarks on the same will be pub- lished, when presented to the Secretary by the author in writing within two weeks of the evening of their delivery, and approved by the Committee on Publications. Brief abstracts prepared by one of the Secretaries and approved by the Committee on Publications may also be published. 5. If the author of any paper read before a Section of the Society desires its publication, either in full or by abstract, it shall be referred to a committee to be appointed as the Section may determine. The report of this committee shall be forwarded to the Publica- tion Committee by the Secretary of the Section, together with any action of the Section taken thereon. 6. Communications which have been published elsewhere, so as to be generally accessible, will appear in the Bulletin by title only, but with a reference to the place of publication, if made known in season to the Committee on Publications. 28 xii* OFFICERS PHILOSOPHICAL SOCIETY OF WASHINGTON Elected December 20, 1884. President Asaph Hall. Vice-Presidents J. S. Billings. Garrick Mallery. William Harkness. J. E. Hilgard. Treasurer Robert Fletcher. Secretaries G. K. Gilbert. Henry Farquhar. MEMBERS AT LARGE OF THE GENERAL COMMITTEE. Marcus Baker. H. H. Bates. F. W. Clarke. W. H. Dall. C. E. Dutton. J. R. Eastman. E. B. Elliott. H. M. Paul. C. V. Riley. STANDING COMMITTEES. On Communications : J. S. Billings, Chairman. G. K. Gilbert. Henry Farquhar. On Publications : G. K. Gilbert, Chairman. Robert Fletcher. Henry Farquhar. S. F. Baird.* * As Secretary of the Smithsonian Institution. XIV OIFIFXaHIIR.S PHILOSOPHICAL SOCIETY OF WASHINGTON Elected December 19, 1885. President J. S. Billings. Vice-Presidents William Harkness. Garrick Mallery. C. E. DUTTON. J. E. HlLGARD. Treasurer Robert Fletcher. Secretaries G. K. Gilbert. Marcus Baker. MEMBERS AT LARGE OF THE GENERAL COMMITTEE. H. H. Bates. F. W. Clarke. W. H. Dall. C. E. Dutton. J. R. Eastman. Henry Farquhar. T. C. Mendenhall. H. M. Paul. C. V. Riley. Standing committees. On Communications : William Harkness, Chairman. G. K. Gilbert. Marcus Baker. On Publications: G. K. Gilbert, Chairman. Robert Fletcher. Marcus Baker. S. F. Baird.* * As Secretary of the Smithsonian Institution. XV LIST OF MEMBERS OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. Corrected to January i6, 1886. The customary titles of members are hero for the first time given. Names of gentlemen hero indicated as resigned will be omitted from future lists. Name. Address and Eesidence. Abbe, Prof. Cleveland • ABEBT, Mr. S. T.(Sylvanus Thayer) Adams, Mr. Charles Frederick Adams, Mr. Henry Alois, Hon. A. O. (Asa Owen) Antisell, Dr. Thomas [Founder) Avery, Mr. RoBEBT S. (Robert Stanton) Baird, Prof. SPENCEB P. (Spencer Fullerton) (Founder) BAKER, Dr. Frank Baker, Mr. Marcus Bancroft, George Barnard, Dr. Wm. S. (William Stebbins) Barus, Dr. Carl BATES, Mr. Henry H. (Henry Bobart) Beardslee, Capt. L. A. (Lester Anthony) U. S. N. {Absent) Bell, Mr. A. Graham (Alexander < rraham) Bell, Dr. C. A. (Chichester Alcx- ander) Benet, Gen. S. V. (Stephen Vin- cent) U. S. A. (Founder) Army Signal Office. 1871 2017 I st. N. W. 810 19th st. N. W. 1875 Civil Service Commission. 1885 2017 G st. N. W. 1G07 H st. N. W. 1881 1765 Muss. ave. N. W. ' 1873 Patent Office. 1871 1311 Q st. N. W. 320 A st. S. E. 1879 Smithsonian Institution. 1445 Mass. ave. N. W. 326 C st. N. W. 1881 Coast and Geodetic Survey Office. 1876 1205 Rhode Island ave. 1623 II st. N. W., or Newport, R. I. 917 New York ave. N. W., or Canton, 111. Geological Survey. 1885 Patent Office. 1871 The Portland. Navy Department. 1875 Scott Circle; 1500 Rhode Island ave. 1314 19th st. N. W. Ordnance Office, War Dept. 1717 I st. N. W. XVI LIST OP MEMBERS. XVII Name. XVIII PHILOSOPHICAL SOCIETY OF WASHINGTON. Name. LIST OF MEMBERS. XIX Name. Address and Eesidence. Gallatjdet, President E. M. (Ed ward Miner) Gannett, Mr. Henry Gihon, Dr. Albert L. (Albert Leary) U. S. N. (Resigned) Gilbert, Mr. G. K. (Grove Karl) Godding, Dr. W. W. ("William "Whitney) Gooch, Dr. F. A. (Frank Austin) Goode, Mr. G. Brown (George Brown) Goodfellow, Mr. Edward Gore, Prof. J. H. (James How- ard) Graves, Mr. "Walter H. (Wal- ter Hayden) (Absent) Greely, Lieut. A. "W. (Adol- phus Washington) U. S. A. Green, Mr. Bernard 11. (Bern- ard Eichardson) Green, Commander F. M. (Fran- cis Mathews) U. S. N. (Absent) Greene, Prof. B. F. (Benjamin Franklin) (Founder: absent) Greene, Capt. Francis V. (Fran- cis Vinton) U. S. A. (Absent) Gregory, Dr. John M. (John Milton) Gunnell, Francis M., M. D., IT. S. N. Hains, Col. Peter C. (Peter Conover) Hains, Mr. Kobert P. (Kohert Peter) Hall, Prof. Asaph, U. S. N. (Founder) Hall, Mr. Asaph, Jr. Hallock, Dr. William Hampson, Mr. Thomas Harkness, Prof. William, U. S. N. (Founder) Deaf Mute College, Kendall Green. Geological Survey. 1881 Harewood ave., Le Droit Park. Geological Survey. 1424 Corcoran st. Government Hospital for the In- sane. Geological Survey. 825 Vermont ave. National Museum. 1545 T st. N. W. Coast and Geodetic Survey Office Columbian University. 1305 Q st. N. W. Denver, Colorado. Armv Signal Office. 1914 G st N. W. 1738 N st. N. W. Navy Department. West Lebanon, N. H. West Point, N. Y. 15 Grant Place. GOO 20th st., N. W. Engineer's Office, Potomac Kiv. Improvement, 2136 Pa. ave. 1824 Jefferson Place. Patent Office. 1714 13th st. N. W. Naval Observatory. 2715 N st. N. W. Yale College Observatory, New Haven, Conn. 2715 N st. N. W. Geological Survey. Geological Survey. 504 Maple ave., Le Droit Park. Naval Observatory. Cosmos Club, 23 Madison Place. 1875 1874 1880 1873 1879 1885 1874 1875 1880 1878 1880 1879 1875 1871 1875 1884 1879 1879 1885 1871 1884 1885 1885 1871 XX PHILOSOPHICAL SOCIETY OF WASHINGTON. Name. LIST OF MEMBERS. XXI Name. XXII PHILOSOPHICAL SOCIETY OF WASHINGTON. Name. Address and Residence. Morgan, Dr. E. C. (Ethelbert Carroll) Moser, Lt. J. F. (Jefferson Frank- lin) U. S. N. Murdoch, Mr. John Mussey, Gen. R. D. (Reuben Del- avan) Myers, Gen. William, U. S. A. Netvcomb, Prof. Simon, U. S. N. [Founder) Nichols, Dr. Charles H. (Charles Henry) [Absent) Nicholson, Mr. W. L. (Walter Lamb) (Founder) Nordhoff, Mr. Charles Norris, Dr. Basil IT. S. A. (Ab- sent) Nott, Judge C. C. (Charles Cooper) Ogden, Mr. Herbert G. (Herbert Gouverneur) Osborne, Mr. J.W. (John Walter) Parke, Gen. John G. (John Grubb) U. S. A. (Founder) Parker, Dr. Peter (Founder) Parry, Dr. Charles C. (Charles Christopher) (Absent) Paul, Mr. H. M. (Henry Martyn) Peale, Dr. A. C. (Albert Charles) Pilling, Mr. James C. (James Constantine) (Resigned) Poe, Gen. O. M. (Orlando Met- calfe) U. S. A. (Absent) Poindexter, Mr.W. M. (William Mundy) Pope, Dr. B. F. (Benjamin Frank- lin) U. S. A. Powell, Major J. W. (John Wesley) Prentiss, Dr. D. W. (Daniel Webster) Pritchett, Prof. H. S. (Henry Smith) (Absent) 918 E st. N. W. Coast and Geodetic Survey Office 7 2d st. S. E. Smithsonian Institution. 1441 Chapin st., College Hill. P. O. Box 618. 508 5th st. N. W. War Department. Naw Department. 941 M st. N. W. Bloomingdale Asylum, Boule- vard and 117th st., New York, N. Y. Topographer, P. O. Dept. 1322 1st. N. W. 1731 K st. N. W. Vancouver, Clarke Co., Wash. Ter. Court of Claims. 826 Connecticut ave. N. W. Coast and Geodetic Survey Office 1324 19th st. N. W. 212 Delaware ave. N. E. Engineer Bureau, War Dept. 16 Lafayette Square. 2 Lexington Place. Davenport, Iowa. Naval Observatory. 109 1st st. N. E. Geological Survey. 1010 Mass. ave. N. W. 34 Congress st. West, Detroit, Mich. 701 15th st. N. W. 806 17th st. N. W. Surg. General's Office, U. S. A. Geological Survey. 910 M st. N. W. 1224 9th st. N. W. Director of Observatory, Wash. University, St. Louis, Mo. 183 184 1«2 1374 880 1879 LIST OF MEMBEKS. XXIII Name. Address and Residence. Rathbun, Mr. Richard (Gus-Ravene, Mr. Gustave L, tave Louis) Ray, Lieut. P. H. (Patrick Henry) U. S. A. Renshawe, Mr. Jno. H. (John Henry) Richey, Dr. S. O. {Resigned) Ricksecker, Mr. Eugene Riley, Dr. C. V. (Charles Valen- tine) Ritter, Mr. W. F. McK. (Will- iam Francis McKnight) Robinson, Mr. Thomas Rogers, Mr. Joseph A. (Joseph Addison) (Absent) Russell, Mr. Israel C. (Israel Cook) Russell, Mr. Thomas Salmon, Dr. D. E. (Daniel Elmer) Sampson, Commander William Thomas U. S. N. [Absent] % Saville, Mr. J. H. (James Ham- ilton) Schott, Mr. Charles A. (Charles Anthony) (Founder) Shellabarger, Hon. Samuel Sherman, Hon. John Shufeldt, Dr. R. W. (Robert Wilson) U. S. A. (Absent) Shumway, Mr. W. A. (Willard Adams) (Resigned) Sicard, Capt. Montgomery, U. S. N. Sigsbee, Commander C. D. (Charles Dwight) U. S. 1ST. (Ab- sent) Skinner, Dr. J. O. (John Oscar) U. S. A. Smiley, Mr. Chas. W. (Charles Wesley) Smith, Chf. Eng. David, TJ. S.N. Smithsonian Institution. 1882 1622 Mass. ave. 1417 6th st. N.' W. 1885 Fort Gaston, Cal. 1884 Geological Survey. The Woodmont. 1882 Geological Survey. 1884 1323 Q st. N. W. Agricultural Department, or 1878 National Museum. 1700 13th st. N. W. Nautical Almanac Office. 1879 16 Grant Place. Howard University. 1884 6th st. N. W., cor. Lincoln. Naval Observatory. 1872 Geological Survey. 1882 1424 Corcoran st. Army Signal Office. 1883 1447 Corcoran st. N. W. Agricultural Department. 1883 1337 loth st. N. W. Torpedo Station, Newport, R. I. 1883 1419 F st. N. W. 1871 1315 M st. N. W. Coast and Geodetic Survey Office. 1871 212 1st st. S. E. Room 23 Corcoran Building. 1875 812 17th st. N. W. U. S. Senate. 1874 1319 K st. N. W. Surg. Genl's Office, U. S. A., or 1881 Box 144, Smithsonian Inst. 1885 Ordnance Bureau, Navy Dept. 1877 Navy Department. 1879 Surg. General's Office, U. S. A. 1883 1529 O st. N. W. U. S. Fish Commission. 1882 943 Mass. ave. 1330 Corcoran st. 1876 XXIV PHILOSOPHICAL SOCIETY OF WASHINGTON. Name. LIST OP MEMBERS. XXV Name. XXVI PHILOSOPHICAL SOCIETY OF WASHINGTON. Name. Alexander B. Dyer . Amos Beebe Eaton Charles Ewing Elislia Foote John Gray Foster Leonard Dunnell Gale . Isaiah Hanscom Joseph Henry Franklin Benjamin Hough . Andrew Atkinson Humphreys Ferdinand Kampf "Washington Caruthers Kerr Jonathan Homer Lane Oscar A. Mack . Archibald Robertson Marvine Fielding Bradford Meek James William Milner Albert J. Myer . George Alexander Otis Carlile Pollock Patterson Titian Bamsay Peale Benjamin Peirce John Campbell Kiley John Bodgers Benjamin Franklin Sands George Christian Shaeffer Henry Bobinson Searle "William J. Twining Joseph Janvier "Woodward John Maynard "Woodworth Mordecai Yarnall Admitted, Founder Founder 1874 Founder 1873 1874 1873 Founder 1879 Founder 1875 1883 Founder 1872 1874 Founder 1874 Founder Founder 1871 Founder Founder 1877 1872 Founder Founder 1877 1878 Founder 1874 1871 Active members Absent members SUMMARY. 179 46 Total Deceased members 225 45 mf secretaries' report. xxvii ANNUAL REPORT OF THE SECRETARIES. Washington, City, December 19, 1885. To the Philosophical Society of Washington : We have the honor to present the following statistical data for 1885. At the beginning of the year the number of active members was........... 173 This number has been increased by the addition of 22* new members and by the return of 3 absent members. It has been diminished by the departure of 6 members, by the de^ith of 1, by the resignation of 5, and by the dropping of 7 for non-payment of dues. The net increase of active members has thus been 6 And the active membership is now .' . . . .179 The roll of new members is : C. F. Adams. H. L. Hodgkins. W. A. Shumway. Carl Barus. J. P. Iddings. W. H. Weed. T. M. Chatard. B. P. Mann. Bailey Willis. P. A. Goocu. C. F. Marvin. H. M. Wilson. E. P. Hains. . T. C. Mendenhall. J. L. Wortman. William Hallock. J. F. Moser. G. M. Wright. Thomas Hampson. C. C. Nott. Alex. Ziwet. G. L. Bavene. The names of deceased members (active and absent) are : Horace Capron. F. B. Hough. W. C. Kerr. T. R. Peale. ' There have been 16 meetings for the presentation and discussion of papers (not including the public meeting of Dec. 5) ; the average attendance has been 48. There have been 6 meetings of the Mathe- matical Section ; average attendance 15. In the general meetings 32 communications have been presented ; in the mathematical section 14. Altogether 46 communications have been made by 32 members and one guest. The number of members who have participated in the discussions is 41. The total number who have contributed to the scientific proceedings is 54, or 31 per cent, of the present active membership. The General Committee has held 17 meetings. Attendance below 10 on one evening only, and four times as high as 15. Average 12.2. Corresponding average last year 11.9, and in 1883 10.3, when the attendance was below 10 at five meetings. Very respectfully, G. K. Gilbert, Henry Farquhar, Secretaries. *The figures in this report have been brought down to Jan. 16, 1886, so as to correspond with the list of members. They differ somewhat from those read to the Society at the annual meeting. XXVIII PHILOSOPHICAL SOCIETY OP WASHINGTON. REPORT OF THE TREASURER Mr. President and Gentlemen : The report which I have the honor to present to you to-night covers the pecuniary transactions of the fiscal year which termi- nates with this meeting. You will see from the statement which I shall presently read that the total receipts by the Treasurer have been $1,224.04, and the total disbursements §740.02, leaving a cash balance of $484.02. These sums do not, however, represent the net income and expendi- ture for the year, since the receipts include a balance transferred by the former Treasurer, and the amount collected of unpaid dues of previous years. The payments, also, include the sum of $104.12, for unpaid debts of 1884. All the liabilities of the Society have been discharged to date, and the actual income belonging to 1885 has been $1,041.00, which includes $205.00 of dues yet outstanding. The disbursements for the same period have been $635.90, leaving a net saving for the cur- rent year of $405.10. The unpaid dues of former years which have been collected, amount to $160.00. The Government bonds which belong to the Society were at the beginning of the year exchanged for new issues of the same amounts and denominations. This was done, under authority of the General Committee, in order to obtain uniformity in the designation of the Society, the former bonds having varied from each other in that particular. The bonds consist of:— 1 $1,000 00 bond, bearing interest at 4 per cent. 1 500 00 " " " 4 1 1,000 00 " " " 4h " Total, $2,500 00. The assets of the Society are as follows:— Cash, with Riggs & Co. . . . $482 02 Bonds 2,500 00 Unpaid dues 295 00 Total $3,279 02 The market value of the bonds is, of course, considerably in excess of their face value; on the other hand, a part of the "un- paid dues" will probably not be collected. I have in my possession a still ample stock of the Bulletins. A copy of Vol. VII was sent directly after its publication in February last to every member entitled to receive it, as well as to the various societies and scientific journals, at home and abroad, with which it has been customary for the Society to exchange publications. TREASURER S REPORT. XXIX o .5= ?ss GQ ~ a bo i <» - a ~ ~ » p . ft.2 cm -* rt oo 1-1 TH ^ i a i ^ »H ^ CO t-i c - o &, ^ » « o x ,o « -*-3 CO lT — C 3 p ^ =3 — S °O ^ ^ a ^ Si CO J3 +? * e3 ^ a =2 £ « «- ^ ~ g o co fe .S s "3 ^ O 5 —i o en O i— i Pk o ft* assing of resolutions, so common in all American bodies, might perhaps better be omitted. In such large bodies there is apt to be so much confusion and dis- pute that the resolutions are made extremely vague and meaning- less or are manipulated to suit the purpose of a few. There is another danger to this society arising from its easy conditions to membership and its rapid increase of members. Our country pro- duces a large number of men and women who are born with a mis- sion. Educated in the schools and colleges, but never attaining much distinction as scholars, these people begin in their own phrase to think for themselves. The result of this thinking is often some discovery in science, and one that contravenes doctrines estab- lished by long observation and study. The questions considered are generally vast and mysterious, such as the origin of gravitation, the nebular hypothesis, and the nature of force. Having made his discovery the author wishes of course to present it to the world, and what method is more convenient than through a scientific society, admission to which is so easy. And if we admit a person to mem- bership and take his money how can we refuse to listen to his theories. Who that has had the honor of presiding over one of the sections of the American Association, in casting his eye over XL PHILOSOPHICAL SOCIETY OF WASHINGTON. the audience, has not had brought to mind the description of Dean Swift : " The first man I saw was of meagre aspect, with sooty hands and face; his hair and beard long, ragged, and singed in several places. He had been eight years upon a project for extracting sunbeams out of cucumbers, which were to be put into phials hermetically sealed, and let out to warm the air in raw and inclement summers. He told me he did not doubt in eight years more he should be able to supply the governor's gardens with sunshine at a reasonable rate ; but he complained that his stock was low, and he entreated me to give him something as an encouragement to ingenuity, especially as this had been a dear season for cucumbers." Now although this matter has a comical phase, it has also its serious and difficult side. No man of science wishes to suppress the opinions of others, and ingenious speculations are worthy of atten- tion, but he has a right to his own time, and should be freed from the trouble of listening to absurd projects. How this can be done with such an easy course of admission to membership I do not see. There is another hindrance to the successful operation of the Ameri- can Association which comes from the great extent of our country and the cost and difficulty of attending its meetings. To those who have ample time and means at their disposal this hindrance is not, perhaps, very great. This vigorous and generous society may need a little pruning, but on the whole its influence has been good, and every one must wish it a long and honorable life. We have another scientific organization of national character in the National Academy of Sciences, established in 1863. This is a body on a basis quite different from that of the American Associa- tion for the Advancement of Science. The National Academy was brought into existence during a great civil war, and its members were of necessity chosen from one section of the country. It was incorporated by act of Congress, and this act limited the number of its members to fifty. From the language of the act we may fairly infer that the academy was intended to be the adviser of the Gen- eral Government in matters of science. During a time of great civil commotion, when the powers of the Government were greatly extended, such a society would very naturally come into existence; but when the strife had subsided it became an object of criticism. In filling vacancies in its membership it was difficult always to ANNUAL ADDRESS OF THE PRESIDENT. XLI select the best man, and sometimes abler men were left out of the academy than those who had the right kind of influence to be appointed. Scientific men are like other people, and they elect their friends and those whom they think will help them. Within a few years after the close -of the civil war the limitation of the num- ber of members was removed by act of Congress. The National Academy has now the power to determine the number of its members, and for the present this has been practically fixed at one hundred. Whether this number should be increased, and whether its member- ship should be more evenly distributed throughout the country are questions over which the academy has entire control. Its destiny, therefore, is in its own hands, and it is to be hoped, and it is to be ex- pected, that its career will be useful and honorable. To act such a part as this the academy must maintain a high and independent char- acter. It should choose for its members the best and ablest scientific men of the country, and it must never become the tool of the shrewd men who deal out the rich patronage of the Government. That there is need for such an independent body to criticise and assist in the direction of the scientific work done by public authority seems be- yond question. It is assumed, of course, that the General Govern- ment is to carry on scientific works of various kinds, a position which may be disputed by some, but which appears to be already practically conceded. How far the Government should enter on such works, and how much should be left to private enterprise, is a question of public policy. But there are certain works which belong almost of necessity to the General Government. Thus the survey of our coast and harbors, a general geological survey, and a good map of the country seem to belong to the work of the Government. These may be justified on the ground of their utility to the pub- lic. But there are other scientific works, not so directly con. nected with commercial and moneyed interests, that an enlightened government may properly undertake. Why should not there be in this country a first-class national astronomical observatory, where observations may be continued from one age to another with the best instruments of the times? Again, do not the elevated plains of the West offer an excellent opportunity for the determination of an arc of the meridian which may be extended from British America to the City of Mexico, and why cannot our General Government undertake such a determination? Must everything that is not strictly utilitarian be prohibited in the public works of our Repub- XLII PHILOSOPHICAL SOCIETY OF WASHINGTON. lie? I do not think so. On the other hand the things that are purely commercial may generally be left to themselves. But if the Government is to do scientific work it should have the aid of men of science. We all know the tendency of public offi- cials to fall into habits of routine, and to spin out their work to an almost interminable length. There should be, therefore, a body of men who can criticise kindly, but boldly and justly, the labors of officials, and make them perform their duties as they ought. This, I think, should be one of the functions of the National Academy of Sciences. But to make this advice influential the Government must recognize the scientific men of the country, and give them some regular channel of communication through which their opin- ions can be made known to the public and to the executive author- ities. Thus far in the history of our Government the scientific man has generally been regarded as an expert who is to be carefully watched, lest he get the better of the officials who are set over him, and who sometimes undertake to manage affairs of which they have but little knowledge. The jealousy thus engendered is unfortunate. The man of science should be treated just as other men are treated, and there should be no grumbling at paying him a fair recompense for his labor. Our national military and naval academies are costly institutions, and fortunate is the young man who has a Congressman for an uncle or a cousin; but I have never heard a word from any scientific man against the cost of these establishments. So far as I know, their universal sentiment is, let us have the best of instruc- tion in military and naval science, for this is the cheapest. Our public buildings cost vast sums of money, but there is no objec- tion to such expenditures if the buildings are well and solidly constructed, since here, also, the best is the cheapest. On the other hand, is there not something very absurd in the manner the politician looks on the small expenditures for science, and the lavish ones that are voted for other purposes ? Let us take a single case. A public vessel is " repaired," to use an adopted euphemism, at one of our navy yards, and the cost of the repairs amounts to a million of dollars, or more than double the original cost of the ship. There is some astonishment at this, but we are told in a confident manner that the ship is greatly improved in strength and speed. The trial comes off, and while the ship is going along at her utmost speed, with the velocity of nine miles an hour, the engine breaks down. Here is a serious collapse, since before ANNUAL ADDRESS OF THE PRESIDENT. XLIII she was repaired the vessel could make eleven miles an hour. The head of the Department very properly orders an examination. Now, it might occur to superficial persons that those who repaired that ship had made mistakes. But the examining board weighs the evidence carefully, and it deliberately comes to the conclusion that the fault lies wholly with some unknown person who is more than three thousand miles away. The matter is mysterious, but the result is certain. The Government has been cheated, the money is gone, and the local politicians are happy. And the curious thing is that the public accepts the report of the examining board as en- tirely satisfactory. There is not a whisper of dissent from any news- paper in the land. And, after all, it is only half a million dollars, and do we not throw away ten times as much every year on rivers and harbors? Have we not seen a Senator boasting in his speeches that during the last twenty years more of the public money has been expended on the mountain streams of his own State than that State has paid taxes into the public treasury. Now change the case and let us suppose that some scientific man by bad management of his own or by failure of an assistant, has wasted ten thousand dollars of the public money. Ah, this is quite a different matter, and must be looked at from a different stand- point. How soon do we hear some smug official complacently re- mark that he always knew that scientific men cannot do business. And how eagerly the newspapers seize upon the case ; how indig- nant the editors become, and how the head lines flare. Is there one law for the public functionary and another for the man of science ? But it is not right to leave this matter without further considera- tion. When we look at the advantageous position occupied by the officer of the army or navy we see immediately that this doe's not come from any personal merit he may have, but from the fact that he is recognized by law as an essential part of the Government. This position renders him in theory impersonal, and it is assumed that he has no private business of his own, but all his interests are one with those of the public. He has his member of the Cabinet to represent his views. His appropriations never fail, and he has no need to summon men from distant parts of the country to push his bills through Congress. Now, so long as the scientific man is looked upon merely as an expert and an adventurer, and has no regular channel of communication with the Government he will XLIV PHILOSOPHICAL SOCIETY OF WASHINGTON. stand at a great disadvantage Pie may gain a victory now and then, just as militia may sometimes beat regular troops, but the final result is pretty sure to be defeat. The position of the man of science must, therefore, be recognized by law if he is to be con- nected with public works in such a way that he may act freely and usefully. Such considerations will bring up the question of how far the Government is to proceed in the cultivation of science. If Ave examine the history of a country like England, where we have good records for a thousand years, we shall see that there has been a steady tendency toward three results. The first of these is personal liberty. The slave that was bought and sold has been changed to the serf, and the serf to the laborer. These changes have gone on with conflicts, and sometimes with retrograde move- ments, but on the whole they have proceeded until now, in nearly all civilized countries, personal liberty is secured by law. The sec- ond result is the freedom of opinion. To control such au intangible thing as the opinions of men is a difficult matter, but it is a business which many men delight in, and the contest, though old, is yet a living one. When Sir Richard Saltonstall reproached his friends in Boston for persecuting Baptists and Quakers, on the ground that such persecutions made men hypocrites, the Puritan ministers at once replied that hypocrites are much better than profane persons like Baptists and Quakers. But such people have been forced back from one position to another, explaining, apologizing, and retreat- ing, until now in several countries opinion is nearly free. There remain a few able men who pray for more superstition and bigotry, but they are the relics of a past time. The third result is the right of free exchange, and toward this end we have gained but little, since nearly all governments exercise their power in prohibiting among men the free exchange of their products. The general course of events is thus to restrict the sphere of government, and to leave to the individual more and more freedom of action. The chief duty of government is to see that justice is done between man and man, and to this end that the courts are fair and intelligent, and that our iudges are not owned by rich men and corporations; that the public service is honest and efficient, and is not used for personal or polit- ical aggrandizement. But, granting all this, it seems to me that the Government may properly undertake such great scientific works as I have mentioned, with the condition that they be placed under proper control and inspection. To the successful accomplishment ANNUAL ADDRESS OP THE PRESIDENT. XLV of these works the man of science must be brought into the public service. He must be held responsible, just as other officials are, in his account of public money. Such a condition would subject him to some limitations that might be irksome at first, since it is pleas- ant for many to have at their disposal large sums of money which they may use at their pleasure, and almost every one fancies that he could do a great deal of good in this way. But such a method of handling public money is dangerous, and is apt to lead into trouble. Supposing that our public scientific works are to be carried on by men of science, what part the National Academy of Sciences shall act I cannot say, and it is not my province to urge on the Government the services of this academy, but here is a body of scientific men who have pledged themselves to the public service and they should be made to do their duty. And is there not ample room for intelligent criticism and suggestion in all the methods through which the public money is expended ? Take the case of public schools, which is a kind of communism justified on the ground of utility to the State. What shall be the course of educa- tion in these schools ? There is an unfortunate class of our fellow creatures that must be cared for at the public expense, but shall benevolent institutions encourage the production of such beings ? Have we not read of the English poorhouse where were found the grandfather, the father, and the son, all hearty men, — paupers breed- ing paupers? Do not some of our charitable institutions give plausibility to the saying that the mistakes of the good do more harm than the vices of the wicked ? In fact, turn to any of the modes of public expenditure and examples will be found where sober, scientific judgment is necessary for the wise conduct of busi- ness. I come now to consider our own home society, the Philosophical Society of Washington. And, speaking cautiously and soberly, is it not to-day the best local scientific society in the country ? This is owing partly and perhaps chiefly to our position at the Capital of a great people. Men from all sections come back to us as winter approaches, and many of them have interesting information to give. No other city of our country offers such advantages for fresh and early information of the investigations that are going on in the various departments of science. Our libraries in astronomy, math- ematics, and medical science are among the best. As a general 30 XLVI PHILOSOPHICAL SOCIETY OF WASHINGTON. library that of Congress must surpass all others in the country. These are advantages which make Washington an agreeable resi- dence for men of science and literature. I think also our society has a good plan of organization, thanks to the men who formed it. The general business can be safely con- fided to a committee, and in this way the meetings are made more interesting. This committee is so large that by a generous rotation in office most of the members may see and share, if they wish; the governing of the society. We have simple rules and they should always be enforced, since no society can afford to be overawed by any man, especially a society where we all meet as equals and where no favors are to be asked or granted. Our society has been estab- lished on a broad basis, to include all brances of learning, and as we have members from all the professions our meetings ought not to lack in variety of subjects. In such meetings the purpose of a paper should be to present the principal points clearly, and the author may generally trust to the intelligence of his audience to fill in the details. It is the failure to recognize this rule and the lack of arrangement that make some papers so long and tedious. Our society has its home in a beautiful city, and who that has seen its wonderful growth during recent years can doubt its future splendor and greatness ? It is a city cosmopolitan in its character. Being the seat of political power, here will come the enterprising and adventurous from all parts of the country, with additions from other lands. Some of the brightest names in our scientific annals are those of foreigners who have made their homes with us. Let us welcome all earnest men, remembering that the principles of science are universal, and are not confined to any language or country. In respect of personal conduct we can have no better example than the noble man who was our first President, whose simple and devoted life was a model for every scientific man. If we need other inducements to devote ourselves to labors that may not give a great return of money, or lead to easy and luxurious lives, let us remem- ber that we live in a magnificent country, and one that has been dedicated as we hope to the liberty and welfare of the human race. Each one of us may do a little in adding to her scientific renown, which is now only beginning. Let us recall the words of the great Athenian : " I would have you day by day fix your eyes upon the greatness of Athens, until you become filled with the love of her ; and when you are impressed by the spectacle of her glory, reflect ANNUAL ADDRESS OF THE PRESIDENT. XLVII that this empire has been acquired by men who knew their duty and had the courage to do it, who in the hour of conflict had the fear of dishonor always present to them, and who, if ever they failed in an enterprise, would not allow their virtues to be lost to their country, but freely gave their lives to her as the fairest offering which they could present at her feast. The sacrifice which they collectively made was individually repaid to them ; for they received again each one for himself a praise which grows not old, and the noblest of all sepulchres—I speak not of that in which their remains are laid, but of that in which their glory survives, and is proclaimed always and on every fitting occasion both in word and deed. For the whole earth is the sepulchre of famous men ; not only are they commemorated by columns and inscriptions in their own country, but in foreign lands there dwells also an unwritten memorial of them, graven not on stone but in the hearts of men." BULLETIN OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. GENERAL MEETING. BULLETIN GENERAL MEETING 261st Meeting. January 3, 1885. President Hall in the Chair. The Chair announced the election to membership of Messrs. William Mundy Poindexter and Asaph Hall, Jr. The Auditing Committee, appointed at the annual meeting, sub- mitted the following report : Washington, D. C, December 27, 1884. Mr. President and Gentlemen of the Philosophical Society of Washington : We, your committee, appointed at the annual meeting, December 20, 1884, to audit the report of the Treasurer for the year 1884, have the honor to submit the following report : We have examined the statement of receipts of dues from mem- bers, and of interest on bonds, and find the former to be $745, and the latter $95, as appears in the Treasurer's statements of accounts for the year 1884. In addition to the foregoing, $15 were repaid to the Treasurer by a member for extra printing, thus making the total receipts $855. We have examined the vouchers for disbursements for the same period, and find them correct. We have compared the return checks with the vouchers and with the entries in the bank book, and find them correct. We have examined the bank book, and found the balance as set forth to be correct, said balance, deducting the amount of two checks not yet returned, being $183.04, with Messrs. Riggs & Co. 4 PHILOSOPHICAL SOCIETY OF WASHINGTON. The bonds referred to in the statement of assets were exhibited to us by the Treasurer, and consist of one $1,000 U. S. bond @ 4£ per cent., one $1,000 U. S. bond @ 4 per cent., and one &500 U. S. bond also @ 4 per cent. All of which is respectfully submitted. H. C. Yarrow, Marcus Baker, William C. Winlock, Committee. On motion, the report was accepted and the committee discharged. Mr. J. S. Billings made a communication on THE VITAL STATISTICS OF THE TENTH U. S. CENSUS, presenting a brief outline of results soon to be published in Vol. XI of the Census Reports. Remarks were made by Messrs. Elliott, Mallery, and Asaph Hall. 262d Meeting. January 17, 1885. The President in the Chair. The Chair communicated an invitation to the members of the Society to attend the annual meeting of the Biological Society and listen to an address by Dr. C. A. White. By request, Professor G. Stanley Hall, of the Johns Hopkins University, made a communication on RECENT EXPERIMENTS ON REACTION TIME, AND THE TIME SENSE, reviewing the methods of investigation and the results attained. An animated discussion followed by Messrs. Robinson, Hilgard, Newcomb, Billings, Eastman, Paul, Winlock, Asaph Hall, and Professor George Davidson, of San Francisco. Mr. C. E. Dutton then began a communication on practical geology versus speculative physics, which was unfinished when the hour of adjournment arrived. general meeting. 5 263d Meeting. January 31, 1885. The President in the Chair. Fifty-eight members and guests present. The Chair communicated an invitation to the members of the Society to attend the ninetieth regular meeting of the Anthropo- logical Society, and listen to an address by Major J. W. Powell. Mr. C. E. Dutton finished the communication begun by him at the last meeting on PRACTICAL GEOLOGY Versus SPECULATIVE PHYSICS, and the subject was further discussed by Messrs. Doolittle, Mason, Clarke, Ward, Walcott, Paul, Taylor, M. Baker, and Robinson. 264th Meeting. February, 14, 1885. The President in the Chair. Thirty-one members present. The Chair announced the election to membership of Messrs. Carl Barus, Frank Austin Gooch, and William Hallock. Messrs. F. W. Clarke and J. S. Diller made a joint communi- cation on TOPAZ FROM STONEHAM, MAINE, describing the alteration of topaz into damourite. [The paper is published in the American Journal of Science, 3d series, Vol. xxix, pp. 378-384.] Mr. William H. Dall made a communication on TWO REMARKABLE FORMS OF MOLLUSKS. Mr. Dall described the anatomical features of the remarkable Chlamydoconcha Orcutti, of San Diego, California,* which is in fact a degraded lamellibranch, in which the shell has become internal and functionless, and is no longer adjusted by adductor muscles. He also described a remarkable feature which he had just dis- covered in Milneria minima, a small California bivalve, belonging *The main features of this notice appear in Science, No. 76, Vol. IV, p. 50, 1884. G PHILOSOPHICAL SOCIETY OF WASHINGTON. to the Carditidce, and living on the backs of Haliotis shells. The female has the base of the shell pushed up into a dome in the median line, the opening to which is closed by an extension of the mantle. In the pocket so formed the young of the species are protected by the mother. The only other case among the laraellibranchs of such a protective modification is that of Thecalia concamerata, in which the same end is reached in a different manner. Both belong to the same family. The males of Milneria are without the pocket. Both sexes adhere by a byssus. Mr. W. B. Taylor read a communication on GEOLOGICAL AND PHYSICAL THEORIES, in which, controverting the claims of practical or field geology—to the exclusion of physical theory—in the solution of physiographic problems, he contended that the family ties of planetary relationship cannot be disowned by geology. He thought the value of "exter- nal" inductions fully shown by the probable effects of varying eccentricity in the earth's orbit on secular changes of climate, as well as by a reference to the general inter-relation between the meeting boundaries of astronomical, geological, physical, and chem- ical science. On the physical side, he maintained that the sup- posed demonstrations of the earth's comparatively recent consol- idation, (as well as of the limit assigned to the sun's active life,) were entirely inconclusive: first, from the admitted uncertainty of the data, and secondly, from our ignorance that unknown factors might not enter into the problem. He therefore heartily agreed with Captain Dutton in recognizing the strong demands of geological induction for an incomparably longer chronology than terrestrial physics could as yet cipher out.* At the same time, the speaker contended that the certainty remained entirely unimpaired of an origin and a limit to solar—as well as to planetary—energy ; unless we were prepared to accept the absurdity of an infinite potential. He also pointed out that the doctrine of " uniformitarianism " does not require (as sometimes too readily supposed) an unvarying degree of energy in geological dynamics throughout the distant past; but that the contrary was the more probable—if only from the broad generalization that all action whatever has its period or periods of maximum and minimum. *Mr. Taylor's paper was a reply to one by Mr. Dutton, of which tho Society obtained no abstract. See pp. 4 and 5. GENERAL MEETING. 7 On the question whether geology itself gave us " traces of a begin- ning, or prospects of an end," Mr. T. argued that stratigraphical geology unmistakably indicated its own genesis in the plutonic char- acter of its primseval "Archaean," or Laurentian — pointing to a time when the primitive surface was a molten ocean; and that when read in the light of palaeontology such indication of a begin- ning was strengthened into convincing proof by the receding grada- tions of animal and vegetable life, starting in the lower Silurian and its underlying Cambrian, with the humblest invertebrate forms of molluscan and crustacean life, and the simplest cryptogamous thallogens—the marine algse and fucacese. And in this connection he referred to the memorable generalization of Louis Agassiz—that the geological successions of animal types correspond remarkably with the phases of embryonic development—as one of the most sug- gestive contributions ever made to the theory of evolution. The speaker then turned to the question of the earth's interior fluidity ; and after stating that the celebrated mathematical argu- ments of Hopkins from the " precession " value, and of Thomson from the hydrographic tides, had both been practically abandoned by the latter—though he still persisted in his pre-possessions for a solid globe (mainly on the specific-gravity skepticism), Mr. T. said he felt no difficulty whatever in accepting the.geological evidences of a fluid earth enveloped by a flexile, friable egg-shell. With regard to the large amount of contraction and corrugation every where exhibited by this shell, he admitted that Mr. O. Fisher had conclu- sively disproved the sufficiency of Elie de Beaumont's plausible hypothesis that the contraction is due to the secular cooling of the planet. Mr. Fisher had however no better speculation to offer; and the answer to the riddle must come ultimately—not from petrol- ogy; nor from structural, or stratigraphical, or physiographical geology—but from cosmological physics. In conclusion, the speaker urged that the same inductions which so clearly establish the birth, the childhood, and the manhood of our planet, as inevitably impli- cate its decline, decadence, and decease; and he quoted passages from Byron's familiar lines on "Darkness," as in the main a scien- tific prophecy. Mr. Paul spoke of the importance of a recent contribution to the subject of the earth's rigidity by Mr. George H. Darwin. Mr. Gil- bert thought that Darwin's deduction of high rigidity was vitiated by his postulate of homogeneity. 8 PHILOSOPHICAL SOCIETY OF WASHINGTON. The President remarked on the great interest of the discussion opened by Captain Dutton's communication to a preceding meet- ing, and expressed his especial approval of the method in which Mr. Ward had approached the subject. 265th Meeting. February 28, 1885. The President in the Chair. Fifty members and guests present. The Chair announced the election to membership of Messrs. Thomas Corwin Mendenhall, Alexander Ziwet, Howard Lincoln Hodgkins, Bailey Willis, Joseph Paxson Iddings, and C. F. Marvin. Announcement was also made of the death of the Hon. Horace Capron. Mr. C. Abbe made a communication on METHODS OF VERIFYING WEATHER PREDICTIONS, giving a general account of the rules under which the U. S. Signal Office deduces from "indications " and subsequent observations the published percentages of verifications. For purposes of prediction and verification the area of the United States is divided into a small number of districts. The " indication " for each district refers to the subsequent 24 hours, and is compared with the three next following weather-maps constructed from the observations, and the degree of correspondence for each station in the district is marked on a scale of five terms—0, 25, 50, 75, and 100. The published percentages are means of these marks. For certain special classes of phenomena — such as high-winds, frosts, and cold-waves—in which the indication only discriminates the occurrence and non-occurrence of a specific event, the formula for percentage of verification is n -\- o in which n is the whole number of times the event is predicted, v is the number of verifications, or of events coincident with predictions, and o is the number of unpredicted events. It has been found for a large area in Europe, an area comparable GENERAL MEETING. 9 in size with one of the districts above mentioned, that, on the aver- age, a given type of weather — e. g., rain, threatening, fair, hot, cloudy, clear—can prevail simultaneously over only 85 per cent, of the area. If this law holds for the United States, we can hope for no better predictions while the existing system of districts is adhered to, for our percentage of verification is now approximately 85. Mr. Curtis described the method of verification adopted by the Deutsche Seewarte. It differs from that of the U. S. Signal Service in that the predictions are compared for verification with the observations at a single representative station in each district. Thus, for northwest Germany, the observations at Hamburg are employed. The limits for the prediction of stationary temperature are taken as dz 1° C, on the basis of an investigation by Hann who found that the " change in 24 hours at Hamburg, in two-thirds of all cases, averages less than two degrees C." Mr. Curtis showed that, for verifications to be directly comparable with respect to skill in prediction, the limits for " stationary " must vary in different dis- tricts and at different seasons of they ear. Unless such variations are adopted, the verifications should exhibit a uniform geographical difference, and an annual period, if the method employed possesses any scientific accuracy. As any such change of definition would be impracticable, it would seem desirable to base the range allowed for "stationary" temperature entirely on physiological considerations, leaving the question of comparability for subsequent discussion. In reply to a question by Mr. Paul, Mr. Abbe said that the rules required that a prediction covering 24 hours should be verified by the maps compiled at the 8th and 16th hours, as well as by that compiled at the 24th. The desirablity of subdividing the geo- graphic sections to which the weather predictions apply was dis- cussed by Messrs. Gilbert, Paul, and Abbe ; and Mr. Abbe said that if any change was made, it would consist in the abandonment of specially defined districts and the substitution of individual States. Mr. H. A. Hazen remarked that if the prevailing weather in a district treated as a unit actually pertained, on an average, to but 85 per cent, of the district, then only omniscience could attain to a success in weather prediction measured by 85 per cent, of verifica- tion. 10 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. A. Hall made a communication on VARIATIONS OF LATITUDE, discussing the observations tabulated by Mr. Fergola, and reaching the conclusion that the evidence fails to show that latitudes are variable. [The paper is published in the American Journal of Science, 3d series, Vol. XXIX, pp. 223-27.] Mr. R. S. Woodward said that he had recently undertaken the discussion of the subject with somewhat fuller data than those used by Mr. Hall. Postulating that the pole was changing its position by motion at a uniform rate on the arc of a great circle, he. com- puted the direction to be along the meridian 50° west of Green- wich, and the rate of motion about 2" per century. His inves- tigation was not yet completed, but he inclined to the opinion that actual change was indicated by the data used. Other remarks were made by Messrs. Farquhar, Baker, and Paul. 266th Meeting. March 14, 1885. The President in the Chair. Fifty-four members and guests present. The Chair announced the election to membership of Messrs. Robert Porter Hains and George Mitchell Wright. The Chair read a letter from Mr. A. C. Peale, announcing the death, on the 13th of March, of Mr. Titian Ramsay Peale, one of the founders of the Society. Mr. Peale accompanied Colonel Long in his explorations of the Rocky Mountains as naturalist, and was afterwards a member of the Wilkes' exploring expedition. Mr. H. Allen Hazen made a communication on THUNDERSTORMS OF 1884. This paper was a resume of some of the investigations made by the Signal Office, looking to a detailed study of the origin, progress, and development of thunderstorms. Over 13,000 special reports were received and studied. An attempt to connect thunderstorm frequency with the phases of the moon showed a rather marked GENERAL MEETING. 11 increase during the time of new moon, thus corroborating the result previously obtained by Dr. Koppen. A comparison of storm frequency with the period of solar rotation gave a marked maximum during the rotation. It was shown that taking the mean temperature over the whole storm region there was a close relation between the occurrence of high temperature and storm action, the former preceding the latter by about 24 hours. Taking the mean of the meteorological elements on 20 days of many storms at many of the stations, it was found that a marked low-pressure area was present to the northwest of the storm region, there was also a high temperature, while the humidity and weather were normal. On 20 days of few storms the reverse was found true, namely, a relatively high pressure and low temperature, the humid- ity and weather being normal as before. These results were highly interesting as bearing upon the conditions favorable to thunderstorm action. The detailed study gives promise of large additions to our knowledge of these meteors. In the ensuing discussing, Messrs. Mussey, Ray, Antisell, E. Farquhar, Paul, Gilbert, Robinson, and Hazen spoke of the topographic, geographic, and seasonal distribution of thunderstorms and of the relation of the precipitation to the electric phenomena. Mr. Antisell said that moisture is essential to their generation ; they are a secondary effect of the influence of the sun, not a pri- mary. Mr. E. Farquhar spoke of the concentration of electricity by diminution of aqueous surface, when cloud-particles coalesce and form raindrops. Mr. S. M. Burnett exhibited and explained THE JAVAL AND SCHIOTZ OPHTHALMOMETER. Mr. A. B. Johnson began a communication on THE DIFFICULTY IN DETERMINING THE DIRECTION OF SOUND. 267th Meeting. March 28, 1885. The President in the Chair. Forty-two members and guests present. The Chair announced the election to membership of Messrs. Gustave Louis Ravene, Thomas Marean Chatard, Herbert 12 PHILOSOPHICAL SOCIETY OF WASHINGTON. Michael Wilson, Willard Adams Shumway, and Jefferson Franklin Moser. Mr. A. B. Johnson then completed his communication on THE DIFFICULTY IN DETERMINING THE DIRECTION OF SOUND, illustrating his remarks by a model of the topophone. The follow- ing is an abstract of the entire paper. Mr. Johnson said the hunter could not locate his game by the sound it made, unless the sound was frequently repeated ; that the plainsmen could not locate each others' site by shouts, until they were frequently repeated ; that a child calling its mother in a house could not tell which room she was in, or even the floor she was on, until her voice was heard several times ; that it was hard to tell, from its noise alone, whether a street-car was going to the right or left, in approaching it at right angles ; in fact that it was not easy to fix by the ear alone, the location of the source of any sound. A dog aroused from sleep by the call of his unseen master fre- quently dashes in different directions before hitting the right one. Game startled by hearing a hunter's tread will as readily run into, as out of danger. Blind people, despite the highly developed con- dition of their remaining senses, do not appear to be more able to determine the source of sound, other things being equal, than seeing people. It seems to be a question whether people generally do not use sight, touch or smell, involuntarily in locating sound. Hence, when they are so placed that they must depend on hearing alone, and err unusually in doing so, they consider such instances as ab- normal. After referring to subjective errors in audition, which frequently arise, Mr. Johnson spoke of the peculiar class of errors in audition into which mariners are apt to fall, often resulting in disaster. The collision between the ocean steamers Edam and Lepanto, was- referred to, in which the former was sunk, as the latter had erred an eighth of the compass circle in fixing her position by the sound of her fog signal, and thus ran into her. A lawsuit ensued, in which Judge Addison Brown, of the U. S. District Court of New York, decided against the plaintiff, holding " that an error of five points, in locating a vessel by the sound of her whistle in a fog, is not nec- essarily a fault, under the proved aberrations in the course of sound." GENERAL MEETING. 13 Mi*. Johnson then read from Judge Brown's opinion, extracts from papers read before the Washington Philosophical Society by three of its former Presidents, Henry, Taylor, and Welling, and by himself, all as to the difficulty of determining the direction of sound, and he congratulated the Society that its conclusions had been adopted by the courts. As it was evident that the unaided ear could not be relied upon to fix the direction from which sound came, Mr. Johnson said atten- tion should be directed to giving the ear all possible assistance. That something of this kind could be done was proved, he thought, by Professor Morton's experimentation with the topophone. This instrument had been devised by Professor Mayer of the Stevens Institute of Technology. It consisted of an arrangement by which two Helmholtz resonators were connected on the deck of a steamer with rubber tubes running into the cabin and with bars and rods which could be moved from the cabin. The actuating principle of the device was the neutralization of the dynamic force of the full sound wave by the half sound wave, thus approximating silence, and thus indicating automatically, within ten degrees, or less than one point of the compass, the direction of the sound. Mr. Paul remarked that the bar connecting the resonators should be shorter than the wave length of the sound under observation, since otherwise deceptive results would be obtained with the two resonators in similar phases of different waves. Mr. Taylor ques- tioned the utility of the instrument, though heartily applauding its ingenuity. The real difficulty in determining sound direction arises from the heterogeneity of the air in point of density and moisture, and especially from its indeterminate differences of movement, whereby diffractions and refractions are occasioned many times greater than those affecting light. The topophone, like the ear, is cognizant only of the final direction of the incident beam of sound, so to speak, and can tell us nothing of the direction of the source of sound. Mr. E. Farquhar remarked that the verdict of the ear in regard to direction is usually just ; the conditions under which it errs are exceptional. He thought there was a rapid adjustment by motion of the head, from which the general direction is almost in- voluntarily ascertained. Mr. F. Baker said that animals, such as, for example, the carnivora, make fewer mistakes than man, and this is probably due to their muscular control of the external ear. When the ears are pricked up in listening, special tensions may be given o 1 14 PHILOSOPHICAL SOCIETY OF WASHINGTON. to the concha. When man listens intently he adjusts the tensions of the membrana tympani. The possible influence of wind velocity on the pitch of sound was discussed by Messrs. Paul, Taylor, and Gilbert, and other remarks were made by Messrs. King, Hall, Elliott, and H. Farquiiar. Mr. Washington Matthews began a communication on mythological dry paintings of the navajos, which occupied the remainder of the evening. Its completion was deferred. 268th Meeting. April 11, 1885. Vice-President Billings in the Chair. Forty-six members and guests present. Mr. Washington Matthews concluded his paper on MYTHOLOGICAL DRY PAINTING OF THE NAVAJOS. This paper described an art in use among the medicine men of the Navajo Nation, by which they represent various mythological conceptions on the sanded floor of the medicine lodge with dry pig- ments of five different colors. These dry paintings are from ten to twelve feet in diameter, and are quite intricate, containing from five to thirteen mythological figures of large size. About a dozen men labor from eight to ten hours in making them. When completed, they are after some ceremonies completely obliterated, and even the sand on which they are drawn is carried out of the lodge and thrown away. The existence of such an art is not generally known and the figures are not copied from any visible standard but are retained in the memories of the medicine men. The paper was illustrated with seven water-color paintings — reproductions of the Navajo drawings. Four were pictures of the esoteric portion of a Navajo ceremony called dsilyidje-qacal or "song in the mountains," and represented visions or revelations of the Indian prophet who instituted these ceremonies. The remaining three pictures were from a ceremony known as kledje-qacal or "song of the night," and represented the revelations of another Navajo GENERAL MEETING. 15 prophet, lie who, according to their mythology, instituted the latter ceremonies. The symbolism of the pictures was explained, and such portions of the myths as directly referred to the pictures were related. The first picture showed the house of the great snakes. The second represented the gods of the domestic plants, with the prin- cipal domestic plants of the Indians, corn, bean, pumpkin, and to- bacco, indicated by highly conventionalized figures. The third pic- ture was of certain goddesses of great height, called the Bitsihi-nez or Long-bodies, which the prophet is said to have seen in a house made of dewdrops. The fourth drawing depicted the sacred arrows used in the dance, which the medicine men pretend to swallow. The lecturer explained the trick by which this imposture Avas car- ried out. The fifth picture represented the peculiar myth of the tsis-naole or whirling sticks. It represents two logs placed in the center of a lake so as to form a cross. Eight divine beings sat on these logs, which were kept constantly whirling by other gods who poked the logs with plumed staves. There Avere tAvelve apotheosized human figures in the picture. The sixth picture shoAved the kledjc qacal as it took place in the abodes of the gods Avhen the Navajo'prophet first saAV it, and is a fair representation of the dance as it is per- formed among the Na\rajos to-day. The seventh painting repre- sented a portion of the dance among the gods, at a time Avhen a spell had been cast upon them by the angry Coyote-god. The figures in the east of the pictures are painted in Avhite, those in the south blue, those in the Avest yelloAV, those in the north black. This is the usual order of Navajo color symbolism ; but sometimes the Avhite is assigned to the north and the black to the east ; instances Avere given where this interchange took place. The gods in many cases are shoAvn standing on rafts made of sun- beams, such rafts being favorite vessels of the gods Avhen they make their aerial journeys. The gods are depicted Avith round heads, the goddesses Avith quadrangular heads. In the dances, the actors Avear masks of corresponding shapes to indicate males and females. Seven of the pictures Avere surrounded Avith symbols of the rain- boAv deity, Avhich Avith the Navajos, as Avith the Greeks, is a goddess. The sanded floor on Avhich the pictures are drawn is slightly sprinkled with charcoal; this is to convey the idea of a surface of clouds, for it is said that in the houses of the gods these pictures were draAvn on sheets of clouds. 16 PHILOSOPHICAL SOCIETY OP WASHINGTON. The speaker closed by referring to the transitory nature of the pictures, and showing how it might easily have nappened that no knowledge of them would ever transpire. Mr. Gilbert Thompson described pictures on the walls of a shallow cave near San Antonio Spring, New Mexico, and exhibited copies of the same. The outlines of the pictures are etched on the rock, and several different colors are employed, both in the etched grooves and on the plane surface of the rock. Mr. Matthews explained the relations of these drawings to Navajo myths and cere- monies. In response to questions by Messrs. Billings, M. Baker, Paul, and Mallery, Mr. Matthews said that individual drawings are not repeated on the same occasion. The ceremonial dances, most of which take place only during the season when the snakes hiber- nate, are executed for the benefit of invalids, or foi the gratification of individuals who by conventional fiction are regarded as ill. They are paid for, and they are very expensive luxuries, the gross bill of expenses sometimes amounting to the value of $300. The patient or his friends select the particular dance to be performed. After the completion of the picture, the patient enters the lodge, and is seated upon the east figure, while a litany is chanted. Sand from one of the painted figures is then applied to his body, sand from the arm being applied to his arm, &c. Mr. Paul described a similar art of dry-painting, practiced by the Japanese, but for amusement only. Bold designs of great variety are executed skillfully and rapidly in public places, for which the artist receives compensation from the by-standers. Wealthy Japan- ese also employ persons to dance for them, and, for that matter, to fish for them ; but the motive appears to be pleasure, and not religion, or health. Other remarks were made by Mr. Jenkins. Mr. W. C. Winlock made a communication on COMETS II AND III, 1884, illustrating his subject by models exhibiting each cometary orbit in its proper relation to the earth's orbit, and also by plane diagrams and sketches of the comets. GENERAL MEETING. 17 Mr. Ravene spoke of the perturbations of Barnard's comet occasioned by the attraction of Jupiter, and thought it might have been brought into the solar system by that attraction. Other remarks were made by Mr. Paul. Mr. H. M. Paul commenced a communication on PROBLEMS CONNECTED WITH THE PHYSICS OF THE EARTH'S CRUST. Its completion and discussion were deferred to a future meeting. 269th Meeting. April 25, 1885. The President in the Chair. Fifty-three members and guests present. Announcement was made of the election to membership of Mr. Charles Frederic Adams. Mr. Frank Baker made a communication on MODERN IDEAS OF BRAIN MECHANISM. Remarks were made by Messrs. E. Farquhar, H. Farquhar, M. Baker, and Doolittle. Mr. L. F. Ward began a communication on THE FLORA OF THE LARAMIE GROUP, the completion of which was deferred for lack of time. 270th Meeting. May 9, 1885. The President in the Chair. Forty-four members and guests present. Announcement was made of the election to membership of Mr. Walter Harvey Weed. Mr. Lester F. Ward completed the reading of his communica- tion on THE FLORA OF THE LARAMIE GROUP. [It will appear in the Sixth Annual Report of the U. S. Geological 2 18 PHILOSOPHICAL SOCIETY OF WASHINGTON. Survey, as a portion of the author's " Synopsis of the Flora of the Laramie Group."] Remarks followed by Messrs. Gilbert, Elliott, and White. Mr. T. C. Mendenhall made a communication on THE MEASUREMENT OF TEMPERATURE AT DISTANT POINTS. Remarks were made by Mr. Elliott. Mr. Gustave Ravene gave an abstract of a communication pre- pared on THE ASTEROIDS. Remarks were made by Messrs. Taylor, H. Farquhar, and Elliott. 271st Meeting. May 23, 1885 The President in the Chair. Forty-one members and guests present. The Chair announced that only one more meeting would be held before the summer vacation. Mr. A. Graham Bell made a communication on THE MECHANISM OF " CLICKS" AND " CLUCKS." Remarks were made by Messrs. M. Baker, Gilbert, and Rob- inson. Mr. H. M. Paul completed his communication on THE CONDITION OF THE EARTH'S INTERIOR. Mr. W. B. Taylor made a communication on THE CRUMPLING OF THE EARTH'S CRUST, in which, referring to the plausible hypothesis of contraction by cool- ing—which had been so largely accepted, he contended that the amount of cooling and contraction since the formation of a consis- tent crust had been much less than even the opponents of that hypothesis had conceded; while the maximum amounts estimated by its adherents would still be wholly inadequate to represent the GENERAL MEETING. 19 actual measure of compression indicated by the average degrees of plication of the stratified rocks. Supposing these to represent a a reduction from the original circumference of the crust of one-elev- enth, this would involve a former excess of volume of about one- third. The speaker then gave an historical sketch of the growing con- viction among physicists that from the tidal retardation of the earth's rotation, the length of the day must have been much shorter in remote geological eras than at present—and consequently the ob- lateness of the terrestrial ellipsoid considerably greater. Estimating that a day of six hours would give an equatorial enlargement of about one-tenth (without taking any account of volumetric change by reduc- tion of temperature), he thought this morphologic change an adequate explanation of the . observed crumpling of the earth's crust ; and claimed that the cause assigned is both a true and a sufficient one. This larger oblateness would imply an equatorial bulge 396 miles greater in radius than the present ; and a corresponding depression of the poles 658 miles below their present levels. As in a general way confirmatory of this hypothesis, Guyot's statement was quoted that " On the whole, the reliefs begin with the vast, low plains around the polar circle, and go on increasing from the shores of the Arctic ocean toward the tropical regions ; " and that " the ocean basins become less deep toward the North pole — just as the lands become lower toward the same region." [This paper is printed in full in the American Journal of Science, 3d Series, Vol. XXX, pp. 249-266.] 272nd Meeting. June 6, 1885. The President in the Chair. Twenty-eight members present. Mr. J. P. Iddings made a communication on THE COLUMNAR STRUCTURE IN THE DIABASE OF ORANGE MOUNTAIN, N. J. [Abstract.] The paper describes the occurrence and structure of the " trap " rock in the neighborhood of Orange, with special reference to the arrangement of the columns in John O'Rourke's quarry and in the 20 PHILOSOPHICAL SOCIETY OF WASHINGTON. Undercliff quarry in Llewellyn Park. The chief interest centers in the groups of radiating columns which form the, upper portion of the exposures, the lower portion being divided into vertical columns or blocks of larger size. That these two portions of the lava sheet belong to one and the same mass is shown, not only by the contin- uity of the rock of the upper and lower parts, but also by the mutual accommodation of the different sets of columns, which taper off and curve in one direction along lines of oblique junction ; and by the fact that the positions of the columns are not what they should be along the supposed lines of contact. The columnar structure in volcanic lavas is unquestionably a cracking produced by shrinkage upon further cooling, after the mass has consolidated into rock. Considering the origin and progress of a crack produced by the shrinkage of a homogeneous mass, we see that, starting with a plane surface over which forces producing contraction are acting uni- formly, the contraction produced on the surface of the mass in a given time will be greater than that produced at some depth within the mass, and that it will decrease gradually from the surface in- ward. As the contraction progresses, the limit of tension in the direction of the surface will be reached before that in the direction of depth, causing a rapture across the direction of the surface, and as the limit of tension for the layer next to the surface is reached it will rupture in the same direction as the surface layer did, and so on. The direction of the crack is at right angles to that of greatest contraction, or normal to the line of maximum strain. Moreover the condition of the mass at the moment the limit of tension along the surface is reached may be graphically repre- sented as in figure 1, the contraction being a maximum in the ! \ \ FCg.l. top layer and diminishing successively in each layer beneath to that with the initial expansion. The distance of this layer from the surface being taken as unity, the maximum contraction at the GENERAL MEETING. 21 moment of rupture will be equal to twice the tangent of a. In other words 2 tan a represents the limit of tension, and will be con- stant for any given substance. As the conductivity of a cooling body is not directly proportional to the degree of radiation from its surface, Uie difference between the contraction of successive layers of a rapidly cooling mass will be greater than between those of one cooling less rapidly, and what may be styled the angle of contraction will be greater in the former case than in the latter. And if we assume a certain rate of cooling to have caused a single rupture in a given extent of mass (repre- sented in fig. 1), then a greater rate of cooling, which would pro- duce in the same extent of mass a contraction represented by a i a mi t tan /3 greater angle, p, will cause as many ruptures as the ratio, j • If the forces producing contraction are unequally distributed over the surface a b, figure 2, being a maximum at c, the maximum Fig. 2. strain at the beginning will be in the direction of the surface, and the cracks will start normal to it ; but their progress inward will no longer be uniform. At the end of a given time the limit of ten- sion reached by a greater force, at /, will be farther from the sur- face than that reached by a less force, at g, and the line of maxi- mum strain in this portion of the mass will be g'f, to which the crack of parting will be normal. At the end of another given time the direction of the crack will be again changed, and the same action taking place in the other parts of the mass will result in a system of diverging cracks. So far we have considered the shrinkage in one direction in one plane only, that is, parallel to the cooling surface in a plane at right angles to it. But a homogeneous mass contracts equally in all 22 PHILOSOPHICAL SOCIETY OF WASHINGTON. directions, and the contractile force which produces cracks at certain distances in a given mass will exert itself equally in all directions over a surface uniformly subjected to the cooling forces, and will, at the instant of fracture, act towards centres, whose dis- tance apart is dependent on the rate of cooling. If the mass is per- fectly homogeneous the centres of contraction will be disposed over the surface with the greatest uniformity possible, that is, they will be equidistant throughout, and the resultant fractures Avill be in a system of hexagons. If from any irregularity in the composition or petrographic structure of the rock the contractile force acts un- equally in different directions, the form of the polygons will be less regular. The mutual influence of the forces producing different columns as they approach each other is readily understood from the foregoing. Take the case of two columns, S, S', approaching one another (Fig. 3,) and suppose the progress of the maximum strain to have reached a b, a' b', the forces producing contraction acting through a and a' will meet and react on each other before those acting through b and b', so that the points of maximum strain at any given time will have advanced farther along the lines through a and a' than through b and V. The lines of greatest strain will then be c d and c' d', and the cracks normal to them will take the directions e e and c' e\ This will continue till they become parallel. If there were but two columns forming at equal rates they would curve symmetrically and continue in parallel directions and of con. stant width, but if one column progresses more rapidly than the GENERAL MEETING. 23 other they will no longer curve to the same extent, and the slower one will curve more than the faster one. Now, instead of two single columns, there,are always two groups approaching one another, and these prevent the continuation of the columns beyond the bend, pinching them out and causing them to taper off as already observed in the quarry described. The difference in the systems of cracks of the lower and upper portion of this lava sheet may then be accounted for by a difference in the rate of cooling from the lower and upper surfaces, the more frequent fractures arising from the more rapid cooling, and the two systems proceeding from their initial planes until they blend in one another within the mass. If for any reason the cooling from one surface should take place irregularly and from any point proceed more rapidly than from others, it is evident that there would result a set of columns diverg- ing from this point as a focus. Besides the columnar fracturing, a division of the mass by trans- verse cracks, especially near the top of the lava sheet, is more or less noticeable. There remains to be considered the contraction exerted in all other directions through the mass. Since the uniform contraction of a homogeneous body acts equally in every direction through it, its effect corresponds to the equal shortening of the radii of a sphere of such a body. If through any resistance cracking or parting occurs it will take the form of concentric spherical shells. If for any reason the resistance to the contracting force in a par- ticular direction be counteracted by some other force acting in the esame direction the parting will no longer be spherical, but ellipsoidal, as will be seen from Figure 4, where a b c represents a section 3L b through the sphere along the radii of which contraction takes place. A uniform resistance in the direction of the radii represented by 24 PHILOSOPHICAL SOCIETY OF WASHINGTON. c c', d d', etc., will produce a parting parallel to the arc of the circle c' d' e', etc. If, however, the resistance in a direction parallel to ae be neutralized by some force, the resistance along the different radii will be diminished by the amount of the vertical component in each case, and the resulting fracture will be parallel to the ellipse c b'. The relative tendency to fracture also is represented by the area be V. Such a parting is actually present in the large columns in John O'Rourke's quarry, the major axis of the ellipsoid being vertical, as it should be if the weight of the superincumbent mass counteracted any resistance to contraction in a vertical direction. The wavy form of the columns, large and small, suggests irregu- larities in the mass which disturbed the uniform advance of the lines of maximum strain and caused them to deviate from parallelism. The superficial banding of the large vertical columns by nearly horizontal notches or grooves, resembling layers of bricks or rude chiseling, appears to be simply a modification of the plane of the crack. The paper closes with a description of the microscopical charac- ter of the Orange rock, which from its identity with many recvnt basalt flows leads the writer to the conclusion that it should be classed as a coarse-grained basalt or dolerite, as Prof. E. S. Dr.na has called the similar rocks in the Connecticut valley. The occurrence of the rock in question as a surface flow is ren- dered highly probable by its glassy nature, and the disposition of the columns, which resembles that of many lava sheets in western America, as well as of those in central France. G. Poulett Scrope, in his work on "Volcanos" (2d edition, London, 1872), discusses the question of the origin and nature of columnar structure in lavas and other substances, and by a somewhat different course of reasoning arrives at essentially the same conclusions as those reached in the present paper. Mr. W. J. McGee then made a communication on THE TERRACES OF THE POTOMAC VALLEY. Remarks were made by Messrs. Ward, Toner, Robinson and Bates. GENERAL MEETING. 25 273d Meeting October 10, 1885. The President in the Chair. Thirty-nine members and guests present. Announcement was made of the death since the last meeting of two members of the Society, Franklin Benjamin Hough and Washington Caruthers Kerr. Messrs. J. S. Billings and Washington Matthews made a joint communication on anthropometric and reaction-time apparatus. They exhibited a set of the anthropometric apparatus, devised chiefly by Mr. Francis Galton, and recently employed in the anthro- pometric laboratory of the London Health Exhibition. The appara- tus test acuteness of hearing, strength of vision, color discrimination, the estimation of the aliquot parts of a line, the estimation of a right angle, the rapidity of arm movement in striking a blow, the strength of certain muscles, the weight, the height (sitting and standing), span of arms, and chest capacity. Their peculiar characteristic is their simplicity, which permits of their use by the person measured, with a minimum of instruction and supervision. There was also exhibited a device by Mr. James McKeen Cattell, for the determina- tion of the time occupied by various sensations, mental processes and muscular actions. There followed an informal discussion by Messrs. H. A. Hazen, E. Farquhar, Hall, H. Farquhar, Harkness, Mussey, AVood- ward and Mason. 274th Meeting. October 24, 1885. The President in the Chair. Fifty-three members and guests present. Mr. H. Allen Hazen made a communication on THE CONDENSING HYGROMETER AND SLING PSYCHROMETER. [Abstract.] By way of introduction the results of a few experiments were given, tending to show the best interval that can be obtained in the 26 PHILOSOPHICAL SOCIETY OF WASHINGTON. graduation of degrees upon a thermometer scale. These were made with a common vernier of a mercurial barometer. A mark on the vernier was placed at each tenth (by estimation) of intervals of .05", .10", .15", .20", .30", and .40", marked on the limb, and the vernier read for each estimation. Over 1300 readings were made, and these showed little difference in the splitting to tenths for the last 5 inter- vals above, but .05" seemed too small for accurate work. Results and methods of observing the Alluard form of Regnault's condensing hygrometer were given. It was shown that if the ther- mometer immersed in the liquid is placed quite near the plate where dew is to appear, there is little or no danger of the air as it passess into the liquid harmfully affecting the thermometer. The com- plaint of some that the dew is deposited in the air, having a tem- perature frequently 40 or 50 degrees above the liquid, and hence that the thermometer can hardly give a correct dew-point tempera- ture Avas shown to have little weight, since the results, with a slight difference between the air and dew-point, at which time the effect would be small, are neai'ly identical with those where the difference is large, and the effect would be large. It was shown that the great difficulty in nearly all psychrometric work up to the present time has been the disregard of a sufficient ventilation of the wet-bulb thermometer. The sling psychrometer, with a few precautions in its use, furnishes results entirely satisfactory. The comparisons so far made between the two instruments have shown a remarkable uniformity under all conditions of moisture and temperature, and have left little to be determined in order to make either apparatus one of precision. A probable effect of compression of ice on the wet bulb at temperatures of 0° F., and below, was shown to exist, though this may be due to the lack of conduction on the part of the ice for the residuum of heat in the bulb. The question of the effect of height above sea on the indications of the above instruments was touched upon, and it was shown that the effect was small and only to be detected by the most refined obser- vations. Also, that until we have some law for reducing humidity results to sea level, the propriety of introducing such effect into tables is questionable. Mr. T. C. Mendenhall exhibited a new volt-meter devised by Sir William Thompson. The principal difficulty encountered by earlier instruments of this class has arisen from the inconstancy of the magnetic force of the terrestrial field. By this instrument ter- GENERAL MEETING. 27 restrial magnetism is eliminated. The force produced by the current is opposed by a weight and is thus measured in terms of gravity. Mr. Mendenhall also renewed the discussion of the preceding evening on reaction time, reciting the methods and results of his own experiments in 1871. Remarks on the volt-meter were made by Mr. Elliott, on re- action time by Messrs. Paul, Mason, and Matthews. Mr. William Harkness made a communication on FLEXURES OF TRANSIT INSTRUMENTS, pointing out that the flexures induced by the weight of a transit, in positions other than vertical, are not eliminated by reversing the instrument, and developing equations for the discussion of the errors so far as they can be determined by the aid of collimators. 275th Meeting. November 7, 1885. The President in the Chair. Sixty-nine members present. Mr. F. W. Clarke made a communication on AN ATTEMPT AT A THEORY OF ODOR, in which he accounted for the lack of knowledge as to the con- ditions of action of this sense by the difficulty of dissociating it from taste; and, while disclaiming any thought of attempting a physio- logical explanation of the sense, proposed the following as the essen- tial objective conditions : 1. To be odorous, a substance must be volatile, so that it may come into contact with the mucous tissue of the nose, and 2. It must be chemically unstable, so that it may undergo chemi- cal changes in contact with that tissue. Mr. Clarke gave some confirmatory instances, from the compounds of hydrogen with sulphur, selenium, and tellurium, and from the Cn H2Q 2 group of acids (formic, acetic, etc.) Mr. Antisell called attention to the connection between a low boiling-point and simplicity of chemical constitution, and to the associated fact that organic substances containing a large number 28 PHILOSOPHICAL SOCIETY OF WASHINGTON. of equivalents of carbon are inodorous. He ascribed the smell of prussic acid to arriere-gout rather than true odor. * Mr. Billings showed that from the peculiarly exposed condition of the olfactory nerve-terminal, it was subject to irritations that must be distinguished from odors properly speaking. Mr. Clarke then made a communication on THE FLOOD ROCK EXPLOSION, in which he described the arrangements for observing earth tremor at stations near New York city, and particularly that at Ward's Island, occupied by Mr. Mendenhall and himself. The tremor was felt at that station a full second before any disturbance was seen in the surface of the water above Flood Rock. Mr. C. F. Marvin, in a communication on the same subject, de- scribed the form of seismoscope used, in which a small agitation closed an electric circuit, and sounded an alarm. Mr. Paul followed with a communication on the same subject. Mr. Clarke quoted some results of observations made at Gen. Abbot's stations, giving a mean velocity for the tremor from Flood Rock to Pearsall's of 2.6, and to Patchogue of 2\ miles per second, and thus indicating a retarded rate of transmission. Mr. Robinson suggested that the blasts at the new water-works reservoir would afford a good opportunity for measuring the velocity of earth tremors. Mr. H. Farquhar spoke of the sounds coincident with the flight of meteors reported by some observers, as indicating the need of caution in accepting observations of sound in this connection. Mr. Robinson had distinctly heard two sounds after blasts at the water-works; one immediately following the tremor, through the earth, and a later one through the air. Mr. Chatard had made a similar observation in connection with mining blasts. Mr. Dutton said that his impression, from eruptions of Hawaiian volcanoes, had been otherwise, and that the general testimony with regard to earthquakes is that the sound precedes the shock. general meeting. 29 276th Meeting. November 21, 1885. The President in the Chair. Fifty-seven members present. Announcement was made of the election to membership of Mr. Thomas Hampson. The Chair communicated to the members an invitation from the Chemical Society to attend its meetiug on December 10th and listen to the address of its retiring president, Prof. F. W. Clarke. Mr. G. Brown Goode and Mr. C. V. Riley made communica- tions on THE SYSTEMATIC CARE OF PAMPHLETS, exhibiting the appliances employed by them and illustrating their methods. Mr. Goode furnishes each pamphlet with a firm, durable cover, by which it is protected from injury, and at the same time kept separate for convenient use and classification. Photographs, draw- ings, newspaper clippings, etc., are preserved in the same manner. [A full description of his appliances may be found in Science, vol. VI, p. 337.] Mr. RiLEy employs inexpensive, flexible covers, occupying less space, and stores them in the " institute pamphlet case." Mr. B. Pickmann Mann, being invited to participate in the dis- cussion, exhibited his method of binding pamphlets together, a method in which four holes are punched at standard intervals in each pam- phlet and corresponding holes, in flexible hinges to stiff covers, so that a convenient volume can be made up by merely inserting and tying two cords, and any desired rearrangement or insertions can be made, the holes for binding always corresponding. [See Science, vol. VI, p. 407, and Library Journal, vol. VIII, p. 6.] Mr. Billings described the tin boxes used in the storage of the immense file of pamphlets in the library of the Army Medical Museum. Mr. Ward and Mr. Toner spoke in approval of the substantial covers adopted by Mr. Goode. Messrs. Gilbert, Toner and Harkness opposed the binding of several pamphlets together, believing that such combination interferes with their use and ready classification and reclassification. Other remarks were made by Messrs. Dall, Mussey, and Doo- LITTLE. 32 30 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. J. S. Billings made a communication on GERM CULTURES, exhibiting specimens of cultures of chromogenetic and pathogenetic micro-organisms, to illustrate the improvements in methods of investigating these organisms which have been made of late years. Attention was called to the value of culture upon semi-solid media such as peptonized gelatin, agar agar, coagulated blood serum, etc., as a means of differentiating micro-organisms, and of obtaining pure cultures to be used for experimental purposes; and the applications of the method to testing the efficacy of disinfectants, to water examinations, &c, were pointed out. 277th Meeting. December 5, 1885. By courtesy of the officers of the Columbian University, the meeting was held in the law lecture room of the University build- ing. Members of the Anthropological, Biological, and Chemical Societies and their friends were present by invitation. Vice-President Billings occupied the Chair. Present, one hundred and sixty members and guests. The President, Mr. Asaph Hall, read his annual address, taking for his subject : AMERICAN SCIENTIFIC SOCIETIES. [Printed in full on pp. xxxiii-xlvil] A resolution of thanks was moved and unanimously passed. 278th Meeting. December 19, 1885. the fifteenth annual meeting. The President in the chair. Thirty-eight members present. The minutes of the 260th, 276th, and 277th meetings were read and approved. GENERAL MEETING. 31 The Chair announced the election to membership of Mr. Jacob Lawson Wortman. The report of the Secretaries was read and accepted. The report of the Treasurer was read, received, and referred to an auditing committee, consisting of Messrs. J. M. Toner, O. T. Mason, and T. C. Mendenhall. On motion of Mr. Harkness, the thanks of the Society were tendered to the Treasurer and Secretaries for the efficient perform- ance of the duties of their offices. Officers were then elected for the year 1886. (The list is printed on page xv.) The rough minutes of the meeting were read, and the Society adjourned. BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. MATHEMATICAL SECTION. 33 STANDING RULES MATHEMATICAL SECTION, 1. The object of this Section is the consideration and discussion of papers relating to pure or applied mathematics. 2. The special officers of the section shall be a Chairman and a Secretary, who shall be elected at the first meeting of the Section in each year, and discharge the duties usually attaching to those offices. 3. To bring a paper regularly before the Section it must be sub- mitted to the Standing Committee on Communications for the stated meetings of the Society, with the statement that it is for the Mathematical Section. 4. Meetings shall be called by the Standing Committee on Com- munications whenever the extent or importance of the papers sub- mitted and approved appear to justify it. 5. All members of the Philosophical Society who wish to do so may take part in the meetings of this Section. 6. To every member who shall have notified the Secretary of the General Committee of his desire to receive them announcements of the meetings of the Section shall be sent by mail. 7. The Section shall have power to adopt such rules of procedure as it may find expedient. 35 OFFICERS MATHEMATICAL SECTION FOR 1885. Chairman, G. W. Hill. Secretary, Marcus Baker. LIST OF MEMBERS WHO RECEIVE ANNOUNCEMENT OF THE MEETINGS. Abbe, C. Avery, K. S. Baker, M. Bates, H. H. Billings, J. S. Burgess, E. S. Christie, A. S. Coffin, J. H. C. Curtis, G. E. DeLand, T. L. DOOLITTLE, M. H. Eastman, J. E. Eimbeck, W. Elliott, E. B. Farquhar, H. Flint, A. S. Gilbert, G. K. Gore, J. H. Green, B. E. Hall, A. Woodward, E. S. Hall, A. Jr. Harkness, ~W. Hazen, H. A. HlLGARD, J. E. Hill, G. W. HODGKINS, H. L. King, A. F. A. Kummell, C. H. Lefavour, E. B. McGee, W. J. Newcomb, S. Paul, H. M. Kavene, G. L. Eitter, W. F. M'K. EOBINSON, T. Smiley, C. W. Stone, O. Taylor, W. B. Upton, W. W. WlNLOCK, W. C. 36 BULLETIN OF THE MATHEMATICAL SECTION, 16th Meeting. January 7, 1885. The Chairman, Prof. Asaph Hall, presided. Nineteen members and guests present. Election of officers of the Section for the year 1885 was then held and resulted in the selection of Mr. G. "W. Hill as Chairman and Mr. Marcus Baker as Secretary. Mr. E. B. Elliott then presented a communication entitled example illustrating the use of a certain symbol in the calculus of affected quantity. The example selected was a demonstration of the Pythagorean Theorem by the aid of a new symbol. Mr. Marcus Baker presented a communication entitled A COLLECTION OF FORMULAE FOR THE AREA OF A PLANE TRIANGLE, which elicited some criticism of details and of notation. [This paper is published in full in the Annals of Mathematics, vol. 1, No. 6, and vol. 2, No. 1.] Mr. W. C. Winlock (by permission of Rear Admiral S. R. Franklin, Superintendent U. S. Naval Observatory) presented a communication on PHYSICAL OBSERVATIONS OF WOLF'S COMET (1884 III). [Abstract.] The first observation of Wolf's comet that I obtained was with the transit circle of the U. S. Naval Observatory on September 24, 37 38 PHILOSOPHICAL SOCIETY OF WASHINGTON. 1884. The aperture of the instrument is 8 inches and the magni- fying power employed 186. On October 13, using the 9-inch equatorial and a power of 132, " the comet seemed to be a circular nebulous mass with quite a well marked central condensation. The nucleus was not sharply defined, but blended gradually into the fainter light surrounding it." Nov. 8. Transit circle. Nucleus quite well defined. Faint but not difficult to observe. Nov. 12. Transit circle. Nucleus elongated in the preceding fol- lowing direction and apparently composed of a number of bright points. Faint and difficult to observe. The nebulous envelope seems to extend farther on the upper or south side than on the lower side. Seeing, very poor. Nov. 13 with the 9-inch equatorial and the same power as before a sketch (omitted here) was made. The remarks I give sub- stantially as in my note-book : Watched the comet carefully for about an hour (seeing not very good,—a little fog hanging over the river). It is a very slightly oval nebulous object. The central part is a little condensed ; the nucleus proper more so. Filar micrometer measures give for the extent of the outer nebula, meas- ured in the direction of a circle of declination, V 52", and for the inner disc 18". The nucleus is perhaps extended a little in the preceding following direction, but I looked in vain for any indica- tion of the beaded appearance which I thought I saw last night with the transit circle. I might add that using the distance of the comet given in Kriiger's ephemeris these measures would represent distances of 47,000 and 7,500 miles, respectively. No tail. Nov. 20. Transit circle. Nucleus stellar, 10th magnitude. On November 22 another observation was obtained with the 9-inch equatorial, magnifying power 132 as before. Micrometer measures of the outer nebula and the inner disc gave V 30" and 16", respectively, differing but little from the measures of the 13th. Seeing, fair. The following note was made : I divide the comet into three parts, the outer nebula, the inner envelope (or coma I presume it might be called), and the nucleus proper. It is almost impossible to assign a definite limit to this outer envelope, Avavering and flickering like a mass of smoke, but the micrometer measures will fix it roughly. The inner envelope blends into the outer with- out any sharp division, though there is sufficient difference in bright- ness to attempt a measurement. The inner envelope condenses in turn into the brighter nucleus. MATHEMATICAL SECTION. 39 Nov. 24. Transit circle. Nucleus sharp and stellar and about 10th magnitude. Dec. 2. Transit circle. Seeing poor. Extremely faint. Like a 12.5 magnitude star, surrounded by a large but faint nebula. Dec. 8. 9-inch equatorial and power 132. The diameter (in de- clination) of the outer envelope, from a micrometer measurement, w,as 2' 21", the seeing being noted a little better than on Nov. 22. Occasionally I think I see the inner condensed disc, but am not sure of it ; also think that at times there is an indication of a more or less rounded outline to the head on the south preceding side, but it is unstable. Cannot be sure of anything like a tail, and indeed any definite form other than an irregular circle is, after all, largely a matter of imagination. The communication gave rise to some comment and discussion on the difficulties encountered in making satisfactory observations of faint comets and also on the resisting medium in space. Mr. Taylor called the attention of the Section to A SLIGHT MODIFICATION OF THE NEWTONIAN FORMULA OF GRAVITATION with which he had been struck in reading Mr. Bates' paper on " The Physical Basis of Phenomena" recently read before the General Meeting. (See vol. vii, p. 51.) [Abstract.] There is a widespread fallacy — particularly displayed by those kinematists who fancy they have an exceptional insight into the " mechanism of gravitation," that this influence is simply a radiant emanation, necessarily observing the geometry of radial space relations, having as such emanation the same total energy on all concentric spheres whatever their radii, as in the case of luminous radiation for example. Of course every well instructed astronomer and physicist knows that this is not so. In truth " the inverse square " is not geometrical—not a square at all, having no relation whatever to surface,—but simply an algebraical second power, very much like the familiar " velocity squared " (m v X v, or momentum multiplied by velocity), which forms the measure of all kinetic energy and which no one supposes to represent a square. 40 PHILOSOPHICAL SOCIETY OF WASHINGTON. Our late colleague, General Alvord, in confutation of this not un- usual misconception, made a communication to the Society some two or three years ago (as those present doubtless remember) in which he showed that as gravitation was known to act equally on every particle of matter (i. e. proportionally to the mass) and as solid homogeneous spheres subtending any given conical angle from a center of reference possess volumes (or masses, — d being constant) directly proportional to the cubes of the conical altitudes or radii of distance, it follows— if gravity were a radial emanation—its effect must obey the law of inverse cubes of distance, contrary to the facts of observation. The fallacy here criticised springs evidently from the too common tendency to regard gravitation simply as a central force or as a single influence radial in direction, whereas it is always a duplex and reciprocal action ; and however insignificant one of the terminal elements its presence and measure of distance cannot be neglected without completely nullifying all action. Thus m and mf being two masses at any given distance apart, the action in the direction and through the distance m' m, is as real and positive as that in the direction and through the distance m m'. In other words, it would seem that the mutuality of the re-action necessarily involved with it the idea of reciprocity of the distance relation. Thus, adopting the suggestion of Mr. Bates, if we write the formula of the effect as (m -p- d) X (wi' -r- d), we have this reciprocity distinctly brought out, and obtain at once the Newtonian formula. The speaker wished to learn from those more conversant than himself with mathemati- cal literature whether the suggested modification is new, and also whether any mathematical objection appears to its form. Mr. Hill remarked that one fault of the notation proposed ap- peared to be its want of generality, as it is evidently inapplicable to any other force having a higher or different exponent of the space function. Mr. Doolittle observed that, admitting the " reciprocity of the distance relation," he yet failed to perceive how this function could appear in the formula as a product. Why should we write the dis- tance twice taken—as d multiplied by d rather than as d plus dt Further remarks were made by Messrs. Elliott, Bates, and Robinson. mathematical section. 41 17th Meeting. February 10, 1885. The Chairman, Mr. G. W. Hill, presided. Present, eleven members and one guest. In the absence of the Secretary the reading of the minutes of the last meeting Avas deferred, and Mr. R. S. Woodward designated as Secretary pro tern. Mr. Kummell made a communication on AN ARTIFICE SOMETIMES USEFUL FOR THE ADJUSTMENT OF CONDITIONED OBSERVATIONS. [Abstract.] The general process consists in multiplying equations of condition by such factors as will extinguish side-coefficients in the normal equations for correlates. This was shown to be possible in an infinite number of ways. One such way leading to linear equations for the multipliers was shown to require for the extinguishment of all the side-coefficients the solution of the normals, i. e., the very work which was to be evaded. The method would, however, be advan- tageous for the partial extinguishment of large side-coefficients, and the normal equations could thus be solved with advantage by Gauss' indirect method. A useful symmetrical rule was given for extin- guishing the side-coefficients for a pair of conditions. Illustrations of this rule in the adjustment of simple geometrical figures were given, beginning with a simple figure of two triangles and extend- ing to a complete pentagon. Mr. Hill remarked that Jacobi had proposed a similar method for removing side-coefficients. Further remarks were made by Mr. "Woodward. The next communication was by Mr. Gustave L. Ravene on THE THEORY OF MERCURY. [Abstract.] The method here used of computing the secular variation of the elements of an orbit is due»to Gauss. 42 PHILOSOPHICAL SOCIETY OF WASHINGTON. The notation employed for the disturbed body is t: = longitude of perihelion ; = longitude of the ascending node ; i = inclination to the ecliptic ; a = mean distance from the sun ; n = mean annual motion ; e = eccentricity ; tp = eccentric angle = arc sin e ; r = radius vector ; / = true anomaly ; c = eccentric anomaly ; w = mass; and the same symbols with accents, r', 0', i', etc, rep- resent corresponding quantities for the disturbing body. From the definition of the secular perturbations, according to Gauss, the perturbing function may be expressed by 2*2* v m' C f1 — ecose o o in which p is expressed by p 2 = d2 -J- r 2 — 2a' r cos (a', r). We also have r 2 = a2 (1 — e cos e)2 aV cos (a',r) = a' cos e' {cos * (a cos e — ae) — a cos

sin e cos s -f* sin r (a cos e — ae)}. Putting for brevity a2 (1 — e cos e) 2 —- p 2 {cos * (a cos e — ae) — a cos f sin e sin *} = 9£ 2 {sin *(a cos e — ae) -f- a cos

) — «' $ cos e' — a' 8 sin e' I 2* 5 -/{(«" sin e' c?£ j(a'2 + jp ) — a' 5 cos e' — a' s sin efl 2 ' o 2rr COS e' de'T ~/{(«"2 + A)-*j (a' ^£) — a' q cos e' — af 8 sin e' i 2 * o which must be computed for every value of £ obtained by dividing the circumference into,?' parts. If we put a' 2 +P e = x ! <£ % = 9 cos Q ; a' S£ = q sin Q, we get j (a' 2 + p ) — a' g cos e' — a! s sin e'l~* = {A-5cos(£'- Q)}~1 (3) (3) n) = a + 2at cos 2 is expressed by p 2 = a2 -}- a n — 2aa' cos (a7 , a) from which we have dip2) n , d [cos (a, a')] - dT =-2aa m But cos (a, a') = cos e cos e' -j- sin e sin e' cos I, cos I= cos i cos $ -f- sin i sin i' cos (0 — 0'), cot $ sin {6 — 0') — cot i' sin i = — cos (0 — 0') cos i. Differentiating we get d

asses through the feet of the per- pendiculars. The points of bisection on the perpendiculars determined by the circle F are points of bisection in the ordinary sense. The points of bisection on the perpendiculars determined by the f F' circle -j pf, are points of bisection in the extended sense, and in such wise that the segments cut off from A and A', B and B', C and f towards ( away from (d.) Every line drawn' from H to the circumcircle is bisected by the three circles F, F', and F". H is therefore a direct center of similitude common to the circles 0, F, and F' and an inverse center of similitude common to all four circles. 4. The eidocenter is collinear with the circumcenter, orthocenter, and Feuerbach center*; for from a known theorem we have HB = 2 OM, and therefore HO must divide BM into segments of which the greater is twice the less, i. e., it must pass through the eidocenter. 5. Again conceive the triangle AB C (Fig 5) as the base of an oblique cone, etc, as in section 3, except that its vertex is to be con- ceived as perpendicularly over the eidocenter instead of over the orthocenter, and the whole projected as before. In this case FA, EB, EC, and EA', EB',EC are projections of the elements of the cone and EO, coincident with HO from section 4, the projection of the axis. Let the axis be bisected as before by three planes parallel to the base : one midway between apex and base, another below the base, and a third above the apex, and the sections so formed projected upon the plane of the base. *The center of Feuerbach 's circle may be so called for brevity. 50 PHILOSOPHICAL SOCIETY OF WASHINGTON. We then have — (a.) These projections are circles whose diameters are, respect- ively, \, f, and \, the diameter of the circumcircle. Fig. 5. (b.) The centers of the circles F", F'" , F all lie in EO and there- fore in HO joining circumcenter to orthocenter and are points of bisection of EO in both the ordinary and extended sense in such wise that F" E = F" = F'" = FE = i EO. (c.) The segments of the medians EA, EB, EG and EA! , EB', EC are all bisected by each of the circles. In the case of the third circle F, the segments are bisected in the extended sense, and since the segments of the medians, EA, EB, EC, are also bisected in the extended sense by the sides of the triangle the circle F bisects the sides of the triangle. The points of bisection on the medians determined by the circle F" are bisections in the ordinary sense. MATHEMATICAL SECTION. 51 The points of bisection on the medians determined by the circles f F'" j p are points of bisection in the extended sense, and in such manner that the segments cut off from A and A', B and B', C and C are measured from the eidocenter \ ? the vertices. ( away from (d.) Every line drawn from E to the circumcircle is bisected by the three circles F", F'", F ; E is therefore a direct center of simili- tude common to three circles 0, F" , F'" and an inverse center of similitude common to all four circles. 6. If we now compare figures 4 and 6 and consider the three circles in each which resulted from projection, we find that circle F, and only circle F, is identical in the two figures. This identity appears from the fact that their diameters are equal, each equaling half the diameter of the circumcircle, and their cen- ters coincident. The coincidence of their centers appears from drawing the projections of the axes of the cones side by side, thus : F H I 1 1 From Ficr. 4. I- From Fig. 6. E F From Fig. 4 we find that this circle, Feuerbach's, passes through 6 noteworthy points, being 2 points on each perpendicular ; and from Fig. 6 we find that the same circle passes through 6 other noteworthy points, being 2 on each median, or in all Feuerbach's circle passes through 12 noteworthy points. 7. It is apparent from the foregoing that if we should not bisect the axis of the cone but should cut it in any ratio (Fig. 4) by a plane parallel to the base then the projection of the section would be a circle cutting the perpendiculars in that ratio and its center Fn would divide HO in that ratio. The medians would not be divided in that ratio, but a point in HO exists (call it En ) through which, if lines be drawn from the vertices to the opposite sides, these lines would be divided in the given ratio. The four points 0, En , Fn , H would in this case, as before, be four harmonic points. 8. Since Feuerbach's circle bisects the sides of the triangle it is the circumcircle of a triangle similar to the original and of half its 52 PHILOSOPHICAL SOCIETY OF WASHINGTON. size. The results here deduced may therefore be considered to be results of a comparison of the circumcircles of these two triangles. A corresponding study of the relations of the tangent circles (in- and escribed) would therefore be expected to yield many more properties as there are four times as many circles to be considered. Concerning the phrase " bisection in the extended sense," Mr. Doolittle suggested that the term " sesquisection " might be advan- tageously employed. As to the name "nine-points circle," Mr. Kummell said that it was plainly defective, either " six-points " or " twelve-points " circle being satisfactory, according to the point of view taken, but that nine-points circle was not a correct desig- nation from any point of view. Further remarks were made by Mr. Elliott. Mr. C. H. Kummell presented a communication entitled DISTANCES ON ANY SPHEROID. [Abstract.] The present form of solution of the problem to determine the shortest distance between two points on a spheroid which are given by their latitudes and longitudes is characteristic in making use of the Gaussian algorithm of the arithmetico-geometric mean. This and a corresponding transformation of the amplitudes give the necessary elements for computing in three terms the distance precise to the eighth order at least. The form is also remarkable for its symmetry and easy extensibility to still higher precision. Also the preliminary part of the problem in which the excess of the spherical longitude over the spheroidal is determined by succes- sive approximations is much facilitated by the introduction of an angle *7, which is closely related to e, the angle of eccentricity, and which varies between and £. It was thus possible to express the excess of spherical over spheroidal longitude in one term, precise to the 6th order at least [This paper has been published in, full in the Astronomische Nachrichten, No. 2671.] In reply to a question, Mr. Kummell said that the ordinary for- mulae for computing distances between intervisible points on the terrestrial spheroid are all that can be desired. The formulae here MATHEMATICAL SECTION. 53 presented, however, are designed for much greater distances and for any spheroid, and would serve, if need ever arose, for comput- ing the shortest distance between any two points on the terrestrial spheroid no matter how remote. 19th Meeting. April 29, 1885. The Chairman, Mr,, G. W. Hill, presided. Present, nineteen members and one guest. Minutes of the eighteenth meeting read and approved. Mr. A. Ziwet read a paper entitled on grassmann's system of geometry. This paper will appear in full in the Annals of Mathematics, vol. 2, Nos. 1 and 2. In reply to a question by Mr. Curtis as to whether Grassmann's system could be advantageously substituted for the Cartesian sys- tem, Mr. Ziwet expressed the opinion that it could not be so sub- stituted in general, but that it might in certain special cases. Grassmann has not, said Mr. Ziwet, made applications of his method to astronomy, nor indeed does its value consist in its adaptability to the solution of special problems. But for present- ing general geometrical truths it appears superior to Hamilton's methods, to which it is closely related and with which it might be advantageously joined. Mr. Hall remarked that he had seen planetary orbits worked out after Hamilton's method by J. Willard Gibbs, but the process appeared rather more laborious than the usual Gaussian one. The labor of computation of results, Mr. Hill remarked, was practically the same by all methods. By introducing the needful symbols the general expressions may be made exceedingly simple, but when the numerical work begins it will be found that after par- ing off more or less extraneous matter there still remains a central kernel or core of computation from which there is no escape by any method whatsoever. With this view Mr. R. S. Woodward heartily concurred, and added that the supreme test of the usefulness of such systems as 54 PHILOSOPHICAL SOCIETY OF WASHINGTON. Grassruann's, Hamilton's, etc., consists in their ability to reveal new truths ; a test which, according to Mr. Ziwet, Grassmann's system successfully stands. Mr. M. H. Doolittle presented a communication on CAUSE AND CHANCE IN THE CONCURRENCE OF PHENOMENA. The author's views set forth in this communication were stated to be preliminary and incomplete, and he therefore reserves them to be more fully elaborated before publication. 20th Meeting. May 13, 1885. The Chairman, Mr. G. W. Hill, presided. Present, eleven members and three guests. Minutes of the nineteenth meeting, read, corrected, and adopted. Mr. G. L. Ravene read a paper entitled THE ASTEROIDS. This communication elicited a general discussion, participated in by Messrs. Kummell, Ritteb, Baker, Woodward, Elliott, Paul, and Hill. Mr. Ritter then read a paper on SECULAR PERTURBATIONS OF POLYHYMNIA BY JUPITER. [Abstract.] In the computations of these perturbations Gauss's method has been employed, using the formulas adapted to facilitate the appli- cation of this method given by Mr. G. TV. Hill. The eccentricity of Polyhymnia being very large the circum- ference, with reference to the eccentric anomaly of Polyhymnia, has been divided into twenty-four parts. This is a greater number than necessary, but it seemed worth the additional labor required to have the forces and the other quantities involved for as large a number of points as practicable. MATHEMATICAL SECTION. 55 The epoch for both systems of elements is 1873, July, 17.0, Berlin mean time. The ecliptic and mean equinox are for 1873.0. The resulting secular variations in one Julian year are the fol- lowing : Secular variation of the eccentricity, or 5e= + 1".268 " inclination, or C] c + O (t - U] r + O (t - a)] = 0. (2) This shows that in order to secure the complete elimination of the effect of a, c, and r, we must have [PA] = 0, [pC] = 0, [> (t - Q] = 0. (3) The last of these conditions can always be fulfilled by making t - M- (4-)w (4) It may be shown that the value of At corresponding to t as defined by (4) has a maximum weight. A close approximation to the first two conditions of (3) can be secured by selecting for obser- vation stars of suitable declinations and by reversals of the tele- scope. If we put equation (2) gives Af = — At — /? a — yc. (5) This shows that in case /? and y are small, as supposed above, an MATHEMATICAL SECTION. 57 approximate value of At is — A/ . After some preliminary obser- vations at a station it is easy to render a and c small, and their ap- proximate values may always be found from the observation equa- tions by a brief inspection ; so that with such values of a, c, /?, and y as are nearly always readily attainable At may be derived from (5) to the nearest O'.Ol. We may thus dispense entirely with the other three normal equa- tions and reach the same result which would follow from their use. The solution may also be checked ; for by one or two approxima- tions the values of At, a and c which make [_pv] = can be readily found. The practical steps in deriving At from (5) may be summarized as follows : 1. The mean of the observation-equations for clamp west minus the mean of those for clamp east will give an approximate value of the collimation c. 2. The application of this value of c to each observation equation will give a corrected value of (t — a) for each star. 3. An approximation to the value or values of the azimuth will then result by eliminating At from one or more pairs of the corrected observation equations. The azimuth may then be applied to correct the values of (t — a), reached in step 2. 4. The approximate values of a and c will now give an approxi- mate value of At from (5), and the application of this value of At to the values of (t — a), derived in step 3, will give approximate values of v. 5. Form \_pv~\. If this sum is not zero within 0".01 or 3.02, a brief inspection will show what changes in a and c (and possibly Af) will make it zero within those limits. By this process of determining the residuals or their approximate values as soon as possible in the computation any large errors in the values of (t — a) or the azimuth and collimation factors will be easily detected. In precise longitude determinations it is customary to have for each night's observations two complete time determinations, one immediately preceding and one immediately following the tele- graphic comparison of time-pieces. In this case there will be two values of At Calling these At' and At" and denoting the corres- 58 PHILOSOPHICAL SOCIETY OF WASHINGTON. ponding epochs by tj and t" the rate of the time-piece will be given with sufficient accuracy for interpolation by the equation Af - Af r = t" — i' ' l O '0 Mr. Paul thought it an objection to this method that in arrang- ing the groups valuable stars might be lost, so that in a limited time the accuracy of the results would be impaired by the smaller number of observations ; moreover, the method did not furnish the computer with a clear idea of the performance of the instrument. Mr. Hall said that he liked the method, and that he thought it especially good for time work. He had discovered the method once himself, and he knew that it had also been used by Prof. Ormond Stone. Mr. Kummell said that in connection with this subject he had investigated the question of the advisability of using stars towards the pole for time determinations ; that is, he had examined the weight co-efficient formulse to see at what distance north of the zenith a maximum value would be obtained. He found that in general the limit of declination was about 60°. Mr. Paul thought that every weight-formula should take account of the increase of atmospheric disturbance with increase of zenith distance. Mr. Kummell then read the following paper entitled CAN THE ATTRACTION OF A FINITE MASS BE INFINITE ? In Price's Calculus, vol. Ill, art. 201, discussing the result for the attraction of a thin rectangular plate on a particle external to it and in its own plane it is found that if the attracted particle is at an angle of the rectangle the attraction is infinite. Price's method of determining the attraction of plates consists in integrating be- tween the proper limits the following differentials : w_ „ xdxdy ,d?X = mOr *—g ; f\\ (V + ff dzY= mOr V X y 3 ; (1 ) O2 + ff where X= x — axial component of attraction ; Y'= y — axial component of attraction m = mass of attracted particle ; = density of attracting mass, supposed homogeneous ; t = thickness of the plate. MATHEMATICAL SECTION. 59 Referring to the attracted particle as origin let (a , b ) be the corner nearest and (ap b } ) that farthest from the particle; then //"* xdx b aQ = m0rJ*dy ((a » + 2/2)" } ~ « + !/2) *) = muTi < t r- y fo\U + CV + VT hl +W+ hrf ) W and a similar expression for Y by exchanging the a's for the b's. If in this we place a = b = then X= mO- 00. This is taken by Price to be infinite ; yet, since the thickness r must be taken infinitesimal, this is an entirely unfounded conclu- sion. At first, however, I did not suspect this result, and when Mr. Woodward found an infinite attraction of a circular disk on a point at its circumference, which result I checked, it seemed to be possible that the attraction of a finite mass could be infinite. Yet neither Mr. Woodward nor myself was entirely convinced. To settle this question I then resolved to determine the attraction of a right prism and also of a right circular cylinder on a particle at mid- height, which, being then moved to the surface and taking the height infinitesimal, would give the attraction of a plate on a par- ticle in a position at which an infinite attraction had been found. For a right rectangular prism we have, 2h being its height, b x a x h X = mO fdyf xdxJ(g, +^ + g2)f bi + tf){x> + f + h^ w Comparing this with (2), putting 2h = t, we readily see that these values are by no means identical, for (2) is of the form T/2 (av a<» bv b ) while (3) is t/s (av a , bv b , r). Here/2 is independ- ent of r while / 3 is not. 60 PHILOSOPHICAL SOCIETY OP WASHINGTON. Placing a — b = o or supposing the attracted particle at the edge of the prism Ave have b x a,//* xdx b x l/< + f + h* = 2m0h jdyj ^ _ ^ o Vf + V b x V< + y2 + V = 2m0h fdy^ I jj^j] o Vf + A1 6, VV + 2/2 + V = m0 /^['Hpfl <4> o Vf + h2 This form shows clearly that Xvanishes with h; therefore the attraction of a rectangular plate on a particle at one of its corners is not infinite, but, on the contrary, it is infinitesimal. Similarly the attraction of a circular plate on a particle at its circumference may be found by considering the plate a vanishing cylinder. Using cylindrical co-ordinates to a vertical line through the attracted particle as axis we have, if p = horizontal radius vector, v = vectorial angle, for the attraction of a cylinder, radius r, density 0, on a particle at midheight h and distance d from axis of cylinder where p^d3 — r> cosv = 2pd 1 and sin v =^ i/[(d + r)* - f\ |>» - (d - r) 2 ] d-\- r v h A = mOJ p* dpj cos vdvj , , , g.2 f d — r — v — h d-\-r C . 2/*, = mO I p2 dp ' 2 sin v P \/p*+h% d— r MATHEMATICAL SECTION. 61 d + r h Cdp J[(d + r)'-^]l>'-Cd-r)'] - 2m0 SJ T V TTh2 d-r yV— A2 -"iftf-'-JM**-* Vh1 - A2 where a= l/(d + rf -f A2 ; and b = V id — r) 2 + A2 (5) Assume tan

f..... 8 Mathematical communications, Committees on 63 — Section, Bulletin of. 37 Members of 3G INDEX. 67 Page. Mathematical Section, Officers of 36, 37 Rules of 35 Matthews, Washington: communication on mythological dry painting of the Nava- jos „ 14 anthropometric and reaction time apparatus 25 McGee, W. J. : communication on the ter- races of the Potomac valley 24 Measurement of temperature at distant points (Title only) 18 Mechanism of clicks and clucks (Title only) 18 Members, Deceased xxv, xxvii, 8, 10, 25 — List of. xvi — New xxvii Mendenhall, T. C. : communication on mea- surement of temperature at distant points 18 — Election to membership of. 8 — exhibition of a volt meter 26 — remarks on reaction time 27 Mercury, Mathematical theory of. 41 Methods of verifying weather predictions... 8 Milneria minima 5 Modern ideas of brain mechanism (Title only) 17 Mollusks, Two remarkable forms of. 5 Moser, J. F., Election to membership of 12 Mountain structure 18 Mythological dry painting of the Navajos.... 14 National Academy of Sciences xl, xlv Navajos, Painting by 14 Newtonian formula of gravitation 39 Nine-points circle 46 Odor, Theory of. 27 Officers, Election of. 31,37 — of the Mathematical Section 36 Society xiv, xv Orange Mountain, N. J 19 Painting by the Navajos .";. 14 Pamphlets, Care of 29 Paul, H. M. : communication on the earth's interior- 17,18 the Flood Rock explosion 28 — remarks on the earth's rigidity 7 dry painting by the Japanese 16 field time determinations 58 the topophone 13 Peale, T. R., Death of 10 Perturbations of Polyhymnia 54 Physical observations on Wolfs comet (1884, HI) - 37 Poindexter, W. M., Election to membership of 3 Page. Polyhymnia, Perturbations of. 54 Practical geology versus speculative physics (Title only) 4, 5, 6 President's address xxxiii Psychrometers 25 Publications, Committee on xiv, xv Ravene, G. L. : communication on the aste- roids 18,54 the theory of Mercury 41 — Election to membership of. 11 — remarks on comets 17 Reaction time apparatus 25, 27 Recent experiments on reaction time and the time sense (Title only) 4 Report of Secretaries xxvii, 31 Treasurer xxviii, 31 Research, Endowment of. xli Riley, C. V.: communication on the system- atic care of pamphlets 29 Ritter, F. W. McK. : communications on sec- ular perturbations by Jupiter 54 Robinson, T. : remarks on the observation of earth tremors 28 Rules for the publication of the Bulletin xiii — of the General Committee xii Mathematical Section 35 Society }x Secretaries, Report of. xxvii, 31 Secular perturbations ofPolyhymnia by Jup- iter 54 Seismometric observation 28 Shumway, W. A., Election to membership of 12 Signal service investigations of thunder- storms 10 rules for verification of predictions 8 Six-points circle 46 Slight modification of the Newtonian form- ula of gravitation 39 Sling psychrometer 25 Smell, Sense of 27 Societies, American scientific xxxiii Some practical features of a field time de- termination with a meridian transit 55 Sound, Aberration of. n, 12 Spheroid, Distances on 52 Standing rules of the General Committee... xii Mathematical Section 35 Society jx Swift, Dean, cited x l Systematic care of pamphlets 29 Taylor.W. B. : communication on the crump- ling of the earth's crust 18 geological and physical theories 6 a slight modification of the Newton- ian formula of gravitation 39 68 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Taylor, W. B. : remarks on the topophone.... 13 Terraces of the Potomac valley (Title only). 24 Theory of Mercury 41 Thompson, Gilbert, on rock paintings in New Mexico 16 Thunderstorms of 1884 10 Time determination with meridian transit.. 55 Toner, J. M. : remarks on the care of pamph- lets 29 Topaz from Stoneham, Maine 5 Topophone 13 Transit instruments, Flexures of. 27 Trap, Columnar 19 Treasurer, Report of. xxviii, 31 Twelve-points circle 46 Two remarkable forms of mollusks 5 Variations of latitude 10 Velocity of transmission of earth tremors... 28 Verifying weather predictions 8 Vital statistics of the tenth U. S. censua (Title only) 4 Volt-meter, Exhibition of. 26 Ward, L. F.: communication on the flora of the Laramie group 17 Weather predictions, Verification of.„... 8 Page. Weed, W. H., Election /o membership of..... 17 Willis, Bailey, Election to membership of... 8 Wilson, H. M., Election to membership of... 11 Winlock, W. C. : communication on comets II and III, 1884 16 — — — physical observations on Wolfs comet (1884, III) 37 — report of auditing committee 3 Woodward, R. S. : cited on infinite attrac- tion 59, 62 — communication on some practical fea- tures of a field time determination with a meridian transit 55 — remarks on geometric systems 53 infinite attraction of a finite mass.... 63 variations of latitude 10 Wolfs comet 37 Wortman, J. S., Election to membership of.. 31 Wright, G. M., Election to membership of... 10 Yarrow, H. C: Report of auditing com- mittee 3 Ziwet, Alexander: communication onGrass- mann's system of geometry 53 — Election to membership of _ 8 BULLETIN PHILOSOPHICAL SOCIETY WASHINGTON. VOL. IX. Containing the Minutes of the Society and of the Mathematical Section for the year 1886. PUBLISHED BY THE CO-OPERATION OF THE SMITHSONIAN INSTITUTION. WASHINGTON: 1887. CONTENTS. Page. Constitution vii Standing Kules of the Society ix Standing Kules of the General Committee xn Kules for the Puhlication of the Bulletin xiii Officers elected December, 1885 xiv Officers elected December, 1886 . xv List of Members xvi List of Deceased Members xxvi Calendar xxvm Annual Report of the Secretaries z xxix Annual Report of the Treasurer xxx Annual Address of the President, J. S. Billings xxxv Bulletin of the General Meeting 1 Report of the Auditing Committee 3 Notes on the geology of northern California, J. S. Diller 4 Notes on the faults of the Great Basin and of the eastern base of the Sierra Nevada, I. C. Russell 5 Recent changes of level in the basin of Lake Ontario, G. K. Gilbert, (Title only) 8 Lieutenant Lockwood's expedition to farthest north, George E. Curtis 8 Two examples of similar inventions in areas widely apart, O. T. Mason 12 Historical sketch of deep-sea temperature observations, J. H. Kidder, (Title only) 14 Annual profit to banks of national bank note circulation, E. B. Elliott, ( Title only) 14 Quantity of United States subsidiary silver coin existing and in circulation, E. B. Elliott, (Title only) 14 The new star in the nebula of Andromeda, Asaph Hall, (Title only) 14 The images of stars, Asaph Hall, (Title only) 15 On the changes of terrestrial level surfaces due to variations in distribution of superficial matter, R. S. "Woodward, (Title only) 15 On the observed changes of level surfaces in the Bonneville area and their explanation, G. K. Gilbert, (Title only) 15 On the varying altitudes of former level surfaces in the Great Lake region and the applicability of proposed explanations, T. C. Chamberlin, (Title only) 15, 16 The enlargement of mineral fragments as a factor in rock alter- ation, R. D. Irving, (Title only) 16 IV CONTENTS. The subaerial decay of rocks and the origin of the red clay of certain formations, I. 0. Kussell, {Title only) r 16 Kecent improvements in microscopic objectives, with demon- stration of the resolving power of a new l-16th inch, Romyn Hitchcock, {Title only) 16 A phonetic alphabet, Henry Farquhar 17 Customs of every-day life, Garrick Mallery 19 "When I first saw the cholera bacillus, R. D. Mussey, {Title only) 22 The distribution of fishes in the oceanic abysses and middle strata, G. Brown Goode and T. H. Bean, {Title only) 22 The physical geographical divisions of the southeastern portion of the United States and their corresponding topographical types, Gilbert Thompson 22 Temperatures at which differences between mercurial and air thermometers are greatest, Thomas Russell, {with figure)— 25 The gilding of thermometer bulbs, J. H. Kidder, {Title only)- 33 Effects of solar radiation upon thermometer bulbs having dif- ferent metallic coverings, H. A. Hazen 33 Organic cells of unknown origin and form found in human faeces (two cases), Newton L. Bates 35 On museum- specimens illustrating biology, J. S. Billings, G. Brown Goode, and Frederick A. Lucas 35 On geological museums, George P. Merrill, {Title only) 36 The Charleston earthquake, by — T. C. Mendenhall 37 W J McGee 37 Charles G. Rockwood 37 Everett Hayden, {with one plate) 38 H. M. Paul 41 Bowyers and fletchers, O. T. Mason 44 Certain new and small mountain ranges, G. K. Gilbert, {Title only) 45 Normal barometers, T. Russell 46 On the occurrence of copper ores in the Trias of the eastern United States, N. H. Darton, {Title only) 46 The latest volcanic eruption in northern California and its peculiar lavaj J. S. Diller, {Title only) 46 Presentation of the annual address 47 Annual Meeting 47 Bulletin of the Mathematical Section 49 Standing Rules of the Section 51 Officers of the Section 52 List of members who receive announcements of the meetings. 52 Comparison of the Boss and Auwers' declination standards, Henry Farquhar 53 On the position and shape of the geoid as dependent on local masses, R. S. Woodward, {Title only) 53, 54 On the use of Somoff's theorem for the evaluation of the ellip- tic integral of the 3d species, C. H. Kummell, {Title only) 54 Index 55 BULLETIN OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON, CONSTITUTION, RULES, OFFICERS AND MEMBERS, AND REPORTS OF SECRETARIES AND TREASURER. CONSTITUTION OF THE PHILOSOPHICAL SOCIETY OF WASHINGTON. Article I. The name of this Society shall be The Philosophi- cal Society of Washington. Article II. The officers of the Society shall be a President, four Vice-Presidents, a Treasurer, and two Secretaries. Article III. There shall be a General Committee, consisting of the officers of the Society and nine other members. Article IV. The officers of the Society and the other members of the General Committee shall be elected annually by ballot ; they shall hold office until their successors are elected, and shall have power to fill vacancies. Article V. It shall be the duty of the General Committee to make rules for the government of the Society, and to transact all its business. Article VI. This constitution shall not be amended except by a three-fourths vote of those present at an annual meeting for the election of officers, and after notice of the proposed change shall have been given in writing at a stated meeting of the Society at least four weeks previously. STANDING RULES FOR THE GOVERNMENT OP THE PHILOSOPHICAL SOCIETY OF WASHINGTON. 1. The Stated Meetings of the Society shall be held at 8 o'clock p. m. on every alternate Saturday; the place of meeting to be designated by the General Committee. 2. Notice of the time and place of meeting shall be sent to each member by one of the Secretaries. * When necessary, Special Meetings may be called by the President. 3. The Annual Meeting for the election of officers shall be the last stated meeting in the month of December. The order of proceedings (which shall be announced by the Chair) shall be as follows : First, the reading of the minutes of the last Annual Meeting. Second, the presentation of the annual reports of the Secretaries, including the announcement of the names of members elected since the last Annual Meeting. Third, the presentation of the annual report of the Treasurer. Fourth, the announcement of the names of members who, having complied with section 14 of the Standing Rules, are entitled to vote on the election of officers. Fifth, the election of President. Sixth, the election of four Vice-Presidents. Seventh, the election of Treasurer. Eighth, the election of two Secretaries. Ninth, the election of nine members of the General Committee. Tenth, the consideration of Amendments to the Constitution of the Society, if any such shall have been proposed in accordance with Article VI of the Constitution. Eleventh, the reading of the rough minutes of the meeting. 35 ix X PHILOSOPHICAL SOCIETY OF WASHINGTON. 4. Elections of officers are to be held as follows : In each case nominations shall be made by means of an informal ballot, the result of which shall be announced by the Secretary ; after which the first formal ballot shall be taken. In the ballot for Vice-Presidents, Secretaries, and members of the General Committee, each voter shall write on one ballot as many names as there are officers to be elected, viz., four on the first ballot for Vice-Presidents, two on the first for Secretaries, and nine on the first for members of the General Committee ; and on each subse- quent ballot as many names as there are persons yet to be elected and those persons who receive a majority of the votes cast shall be declared elected. If in any case the informal ballot result in giving a majority for •any one, it may be declared formal by a majority vote. 5. The Stated Meetings, with the exception of the Annual Meet- ing, shall be devoted to the consideration and discussion of scientific subjects. The Stated Meeting next preceding the Annual Meeting shall be set apart for the delivery of the President's Annual Address. 6. Sections representing special branches of science may be formed by the General Committee upon the written recommenda- tion of twenty members of the Society. 7. Persons interested in science, who are not residents of the Dis- trict of Columbia, may be present at any meeting of the Society, except the Annual Meeting, upon invitation of a member. 8. On request of a member, the President or either of the Secre- taries may, at his discretion, issue to any person a card of invitation to attend a specified meeting. Five cards of invitation to attend a meeting may be issued in blank to the reader of a paper at that meeting. 9. Invitations to attend during three months the meetings of the Society and participate in the discussion of papers, may, by a vote of nine members of the General Committee, be issued to persons nominated by two members. 10. Communications intended for publication under the auspices of the Society shall be submitted in writing to the General Com- mittee for approval. STANDING RULES. XI 11. Any paper read before a Section may be repeated, either entire or by abstract, before a general meeting of the Society, if such repetition is recommended by the General Committee of the Soj £ .< §• I 1 «2 fl cj'5 2 en "^ co ggigg m « (3S l~- 1 to o.2 _ 33

BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. ANNUAL ADDRESS OF THE PRESIDENT. ANNUAL ADDRESS OF THE PRESIDENT, John S. Billings. Delivered December 4, 1886. SCIENTIFIC MEN AND THEIR DUTIES. Mr. Chairman and Fellow-Members of the Philosophical Society: The honor of the presidency of such a society as this—carrying with it, as it does, the duty of giving at the close of the term of office an address on some subject of general interest, has been aptly compared to the little book mentioned in the Revelations of St. John—the little book which was " sweet in the mouth but bitter in the belly." I can only thank you for the honor, and ask your in- dulgence as to the somewhat discursive remarks which I am about to inflict upon you. There is a Spanish proverb to the effect that no man can at the same time ring the bell and walk in the procession. For a few mo- ments to-night I am to ring the bell, and being thus out of the pro- cession I can glance for a moment at that part of it which is nearest. At first sight it does not appear to be a very homogeneous or well- ordered parade, for the individual members seem to be scattering in every direction, and even sometimes to be pulling in opposite ways; yet there is, after all, a definite movement of the whole mass in the direction of what we call progress. It is not this general movement that I shall speak of, but rather of the tendencies of individuals or of certain classes ; some of the molecular movements, so to speak, which are not only curious and interesting of themselves, but which have an important bearing upon the mass, and some comprehension of which is necessary to a right understanding of the present con- dition and future prospects of science in this country. The part of the procession of which I speak is made up of that body or class of men who are known to the public generally as " scientists," " scientific men," or " men of science." As commonly used, all these terms have much the same significance ; but there are, nevertheless, shades of distinction between them, and in fact we need several other XXXV XXXVI PHILOSOPHICAL SOCIETY OF WASHINGTON. terms for purposes of classification of the rather heterogeneous mass to which they are applied. The word "scientist" is a coinage of the newspaper reporter, and, as ordinarily used, is very comprehensive. Webster defines a scientist as being " one learned in science, a savant "—that is, a wise man—and the word is often used in this sense. But the suggestion which the word conveys to my mind is rather that of one whom the public suppose to be a wise man, whether he is so or not, of one who claims to be scientific. I shall, therefore, use the term "scientist" in the broadest sense, as including scientific men, whether they claim to be such or not, and those who claim to be scientific men whether they are so or not. By a scientific man I mean a man who uses scientific method in the work to which he specially devotes himself; who possesses scientific knowledge,—not in all departments, but in certain special fields. By scientific knowledge we mean knowledge which is definite and which can be accurately expressed. It is true that this can rarely be done completely, so that each proposition shall precisely indicate its own conditions, but this is the ideal at which we aim. There is no man now living who can properly be termed a complete savant, or scientist, in Webster's sense of the word. There are a few men who are not only thoroughly scientific in their own special departments, but are also men possessed of much knowledge upon other subjects and who habitually think scientifically upon most matters to which they give consideration ; but these men are the first to admit the incompleteness and super- ficiality of the knowledge of many subjects which they possess, and to embrace the opportunity which such a society as this affords of meeting with students of other branches, and of making that specially advantageous exchange in which each gives and receives, yet retains all that he had at first. Almost all men suppose that they think scientifically upon all subjects; but, as a matter of fact, the number of persons who are so free from personal equation due to heredity, to early associations, to emotions of various kinds, or to temporary disorder of the digestive or nervous machinery that their mental vision is at all times achro- matic and not astigmatic, is very small indeed. Every educated, healthy man possesses some scientific knowledge, and it is not possible to fix any single test or characteristic which will distinguish the scientific from the unscientific man. There are scientific tailors, bankers, and politicians, as well as physicists, ANNUAL ADDRESS OF THE PRESIDENT. XXXVII chemists, and biologists. Kant's rule, that in each special branch of knowledge the amount of science, properly so called, is equal to the amount of mathematics it contains, corresponds to the definition of pure science as including mathematics and logic, and nothing else. It also corresponds to the distinction which most persons, consciously or unconsciously, make between the so-called physical, and the natural or biological sciences. Most of us, I presume, have for the higher mathematics, and for the astronomers and physicists who use them, that profound respect which pertains to comparative ignorance, and to a belief that capacity for the higher branches of abstract analysis is a much rarer mental quality than are those required for the average work of the naturalist. I do not, however, propose to discuss the hierarchy of the sciences ; and the term science is now so generally used in the sense of knowledge, more or less accurate, of any subject, more especially in the relations of causes and effects, that we must use the word in this sense, and leave to the future the task of devising terms which will distinguish the sciences, properly so called, from those branches of study and occu- pation of which the most that can be said is that they have a scien- tific side. It is a sad thing that words should thus become polar- ized and spoiled, but there seems to be no way of preventing it. In a general way we may say that a scientific man exercises the intellectual more than the emotional faculties, and is governed by his reason rather than by his feelings. He should be a man of both general and special culture, who has a little accurate information on many subjects and much accurate information on some one or two subjects, and who, moreover, is aware of his own ignorance and is not ashamed to confess it. We must admit that many persons who are known as scientists do not correspond to this definition. Have you never heard, and perhaps assented to, some such statements as these : " Smith is a scientist, but he doesn't seem to have good, common sense," or " he is a scientific crank ? " The unscientific mind has been defined as one which " is willing to accept and make statements of which it has no clear conceptions to begin with, and of whose truth it is not assured. It is the state of mind where opinions are given and accepted without ever being subjected to rigid tests." Accepting this definition, and also the implied definition of a scientific mind as being the reverse of this, let us for a moment depart from the beaten track which presi- XXXVIII PHILOSOPHICAL SOCIETY OF WASHINGTON. deutial addresses usually follow, and instead of proceeding at once to eulogize the scientific mind and to recapitulate the wonderful results it has produced, let us consider the unscientific mind a little, not in a spirit of lofty coudescension and. ill-disguised contempt, but sympathetically, and from the best side that we can find. As this is the kind of mind which most of us share with our neighbors, to a greater or less degree, it may be as well not to take too gloomy a view of it. In the first place, the men with unscientific minds form the immense majority of the human race. Our associations, habits, customs, laws, occupations, and pleasures are, ift the main, suited to these unscientific minds ; whose enjoyment of social intercourse, of the every-day occurrences of life, of fiction, of art, poetry, and the drama is, perhaps, none the less because they give and accept opinions without subjecting them to rigid tests. It is because there are a goodly number of men who do this that the sermons of clergymen, the advice of lawyers, and the pre- scriptions of physicians have a market value. This unscientific public has its uses. We can at least claim that we furnish the ma- terials for the truly scientific mind to work with and upon ; it is out of this undifferentiated mass that the scientific mind supposes itself to be developed by specialization, and from it that it obtains the means of its own existence. The man with the unscientific mind, who amuses himself with business enterprises, and who does not care in the least about ohms or pangenesis, may, nevertheless, be a man who does as much good in the world, is as valuable a citizen, and as pleasant a companion as some of the men of scientific minds with whom we are acquainted. And in this connection I venture to express my sympathy for two classes of men who have in all ages been generally condemned and scorned by others, namely, rich men and those who want to be rich. I do not know that they need the sympathy, for our wealthy citi- zens appear to support with much equanimity the disapprobation with which they are visited by lecturers and writers—a condemna- tion which seems in all ages to have been bestowed on those who have by those who have not. So far as those who actually are rich are concerned, we may, I suppose, admit that a few of them—those who furnish the money to endow universities and professorships, to build laboratories, or to furnish in other ways the means of support to scientific men—are not wholly bad. Then, also, it is not always a man's own fault that ANNUAL ADDRESS OF THE PRESIDENT. XXXIX he is rich ; even a scientist may accidentally and against his will become rich. As to those who are not rich, but who wish to be rich, whose chief desire and object is to make money, either to avoid the necessity for further labor, or to secure their wives and children from want, or for the sake of power and desire to rule, I presume it is unsafe to try to offer any apologies for their existence. But when it is claimed for any class of men, scientists or others, that they do not want these things it is well to remember the remarks made by old Sandy Mackay after he had heard a sermon on universal brotherhood : "And so the deevil's dead. Puir auld Nickie ; and him so little ap- preciated, too. Every gowk laying his sins on auld Nick's back. But I'd no bury him until he began to smell a wee strong like. It's a grewsome thing is premature interment." I have tried to indicate briefly the sense in which the terms "sci- entist" and "scientific man" are to be used and understood, and you see it is not an easy matter. The difficulty is less as regards the term "man of science." By this expression we mean a man who belongs to science peculiarly and especially, whose chief object in life is scientific investigation, Avhose thoughts and hopes and desires are mainly concentrated upon his search for new knowledge, whose thirst for fresh and accurate information is constant and insatiable. These are the men who have most advanced science, and whom we delight to honor, more especially in these later days, by glowing eulogiums of their zeal, energy, and disinterestedness. The man of science, as defined by his eulogists, is the beau ideal of a philosopher, a man whose life is dedicated to the advancement of knowledge for its own sake, and not for the sake of money or fame, or of professional position or advancement. He undertakes scientific investigations exclusively or mainly because he loves the work itself, and not with any reference to the probable utility of the results. Such men delight in mental effort, or in the observa- tion of natural phenomena, or in experimental work, or in historical research, in giving play to their imagination, in framing hypotheses and then in endeavoring to verify or disprove them, but always the main incentive is their own personal satisfaction (with which may be mingled some desire for personal fame), and not the pleasure or the good of others. Carried to an extreme, the eulogy of such men and their work is expressed in the toast of the Mathematical Society of England: "Pure mathematics; may it never be of use to any XL PHILOSOPHICAL SOCIETY OF WASHINGTON. man ! " Now, it is one thing to seek one's own pleasure, and quite another thing to pride one's self upon doing so. • The men who do their scientific work for the love of it do some of the best work, and, as a rule, do not pride themselves on it, or feel or express contempt for those who seek their pleasure and amusement in other direc- tions. It is only from a certain class of eulogists of pure science, so called, that we get such specimens of scientific " dudeism " as the toast just quoted, opposed to which may be cited the Arab saying that "A wise man without works is like a cloud without water." There are other men who devote themselves to scientific work, but who prefer to seek information that may be useful ; who try to advance our knowledge of Nature's laws in order that man may know how to adapt himself and his surroundings to those laws, and thus be healthier and happier. They make investigations, like the men of pure science—investigations in which they may or may not take pleasure, but which they make, even if tedious and disagree- able, for the sake of solving some problem of practical importance. These are the men who receive from the public the most honor, for it is seen that their work benefits others. After all, this is not peculiar to the votaries of science. In all countries and all times, and among all sorts and conditions of men, it has always been agreed that the best life, that which most deserves praise, is that which is devoted to the helping others, which is unselfish, not stained by envy or jealousy, and which has as its main pleasure and spriDg of action the desire of making other lives more pleasant, of bringing light into the dark places, of helping humanity. But, on the other hand, the man who makes a profession of doing this, and who makes a living by so doing, the professional philan- thropist, whether he be scientist or emotionalist, is by no means to be judged by his own assertions. Some wise German long ago re- marked that "Esel singen schlecht, well sie zu hoch anstimmen"— that is, " asses sing badly because they pitch their voices too high," and it is a criticism which it is well to bear in mind. In one of the sermons of Kin O * the preacher tells the story of a powerful clam who laughed at the fears of other fish, saying that when he shut himself up he felt no anxiety ; but on trying this method on one occasion when he again opened his shell he found himself in a fishmonger's shop. And to rely on one's own talents, *Cornhill Magazine, August, 1809, p. 196. ANNUAL ADDRESS OF THE PRESIDENT. XLI on the services one may have rendered, on cleverness, judgments strength, or official position, and to feel secure in these, is to court the fate of the clam. There are not very many men of science, and there are no satis- factory means of increasing the number ; it is just as useless to ex- hort men to love science, or to sneer at them because they do not, as it is to advise them to be six feet three inches high or to condemn a man because his hair is not red. While the ideal man of science must have a " clear, cold, keen intellect, as inevitable and as merciless in its conclusions as a logic engine," it would seem that, in the opinion of some, his greatness and superiority consists not so much in the amount of knowledge he possesses, or in what he does with it, as in the intensity and purity of his desire for knowledge. This so-called thirst for knowledge must be closely analogous to an instinctive desire for exercise of an organ or faculty, such as that which leads a rat to gnaw, or a man of fine physique to delight in exercise. Such instincts should not be neglected. If the rat does not gnaw, his teeth will become inconvenient or injurious to himself, but it is not clear that he deserves any special eulogium merely because he gnaws. It will be observed that the definition of a scientific man or man of science, says nothing about his manners or morals. We may infer that a man devoted to science would have neither time nor inclination for dissipation or vice ; that he would be virtuous either because of being passionless or because of his clear foresight of the consequences of yielding to temptation. My own experience, however, would indicate that either this inference is not correct or that some supposed scientific men have been wrongly classified as such. How far the possession of a scien- tific mind and of scientific knowledge compensates, or atones for, ill-bi*eeding or immorality, for surliness, vanity, and petty jealousy, for neglect of wife or children, for uncleanliness, physical and mental, is a question which can only be answered in each individual case ; but the mere fact that a man desires knowledge for its own sake appears to me to have little to do with such questions. I would prefer to know whether the man's knowledge and work is of any use to his fellow-men, whether he is the cause of some happiness in others which would not exist without him. And it may be noted that while utility is of small account in the eyes of some eulogist, 37 XLII PHILOSOPHICAL SOCIETY OF WASHINGTON. of the man of science they almost invariably base their claims for his honor and support upon his usefulness. The precise limit beyond which a scientist should not make money has not yet been precisely determined, but in this vicinity there are some reasons for thinking that the maximum limit is about $5,000 per annum. If there are any members of the Philo- sophical Society of Washington who are making more than this, or who, as the result of careful and scientific introspection, discover in themselves the dawning of a desire to make more than this, they may console themselves with the reflection that the precise ethics and etiquette which should govern their action under such painful circumstances have not yet been formulated. The more they demonstrate their indifference to mere pecuniary considerations the more creditable it is to them ; so much all are agreed upon ; but this is nothing new, nor is it specially applicable to scientists. Yet while each may and must settle such questions as regards himself for himself, let him be very cautious and chary about trying to settle them for other people. Denunciations of other men engaged in scientific pursuits on the ground that their motives are not the proper ones are often based on insufficient or inaccurate knowledge, and seldom, I think, do good. This is a country and an age of hurry, and there seems to be a desire to rush scientific Avork as well as other things. One might suppose, from some of the literature on the subject, that the great object is to make discoveries as fast as possible ; to get all the math- ematical problems worked out ; all the chemical combinations made ; all the insects and plants properly labeled ; all the bones and mus- cles of every animal figured and described. From the point of view of the man of science there does not seem to be occasion for such haste. Suppose that every living thing were known, figured, and described. Would the naturalist be any happier ? Those who wish to make use of the results of scientific investigation of course desire to hasten the work, and when they furnish the means we can- not object to their urgency. Moreover, there is certainly no occa- sion to fear that our stock of that peculiar form of bliss known as ignorance will be soon materially diminished. From my individual point of view, one of the prominent features in the scientific procession is that part of it which is connected with Government work. Our Society brings together a large number of scientific men connected with the various Departments ; some of ANNUAL ADDRESS OF THE PRESIDENT. XLIII them original investigators ; most of them men whose chief, though not only, pleasure is study. A few of them have important administrative duties, and are brought into close relations with the heads of Departments and with Congress. Upon men in such posi- tions a double demand is made, and they are subject to criticism from two very different standpoints. On the one hand are the sci- entists, calling for investigations which shall increase knowledge without special reference to utility, and sometimes asking that em- ployment be given to a particular scientist on the ground that the work to which he wishes to devote himself is of no known use, and therefore will not support him. On the other hand is the demand from the business men's point of view—that they shall show prac- tical results ; that in demands for appropriations from the public funds they shall demonstrate that the use to be made of such appro- priations is for the public good, and that their accounts shall show that the money has been properly expended—"properly," not merely in the sense of usefully, but also in the legal sense—in the sense which was meant by Congress in granting the funds. Nay, more, they must consider not only the intentions of Congress but the opinions of the accounting officers of the Treasury, the comp- troller and auditor, and their clerks, and not rely solely on their own interpretation of the statutes, if they would work to the best advantage, and not have life made a perpetual burden and vexation of spirit. There is a tendency on the part of business men and lawyers to the belief that scientific men are not good organizers or administra- tors, and should be kept in leading strings ; that it is unwise to trust them with the expenditure of, or the accounting for, money, and that the precise direction in which they are to investigate should be pointed out to them. In other words, that they should be made problem-solving machines as far as possible. When we reflect on the number of persons who, like Mark Twain's cat, feel that they are "nearly lightning on superintending;" on the desire for power and authority, which is almost universal, the ten- dency to this opinion is not to be wondered at. Moreover, as re- gards the man of science, there is some reason for it in the very terms by which he is defined, the characteristics for which he is chiefly eulogized. The typical man of science is, in fact, in many cases an abnor- mity, just as a great poet, a great painter, or a great musician is XLIV PHILOSOPHICAL SOCIETY OF WASHINGTON. apt to be, and this not only in an unusual development of one part of the brain, but in an inferior development in others. True, there are exceptions to this rule — great and illustrious exceptions ; but I think we must admit that the man of science often lacks tact, and is indifferent to and careless about matters which do not concern his special work, and especially about matters of accounts and pecuniary details. If such a man is at the head of a bureau, whose work requires many subordinates and the disbursement of large sums of money, he may consider the business management of his office as a nuisance, and delegate as much of it as possible to some subordinate official, who, after a time, becomes the real head and director of the bureau. Evil results have, however, been very rare, and the recognition of the possibility of their occurrence is by no means an admission that they are a necessity, and still less of the proposition that administrative officers should not be scientific men. I feel very sure that there are always available scientific men, thoroughly well informed in their several departments, who are also thoroughly good business men, and are as well qualified for admin- istrative work as any. When such men are really wanted they can always be found, and, as a matter of fact, a goodly number of them have been found, and are now in the Government service. The head of a bureau has great responsibilities; and while his position is, in many respects, a desirable one, it would not be eagerly sought for by most scientific men if its duties w7ere fully understood. In the first place the bureau chief must give up a great part of his time to routine hack work. During his business, or office, hours he can do little else than this routine work, partly because of its amount, and partly because of the frequent interruptions to which he is subjected. His visitors are of all kinds and come from all sorts of motives—some to pass away half an hour, some to get infor- mation, some seeking office. It will not work well if he takes the ground that his time is too important to be wasted on casual callers and refers them to some assistant. In the second place he must, to a great extent at least, give up the pleasure of personal investigation of questions that specially interest him, and turn them over to others. It rarely happens that he can carry out his own plans in his own way, and perhaps it is well that this should be the case. The general character of his work is usually determined for him either by his predecessors, or by Congress, or by the general consensus of opinion of scientific men interested in the ANNUAL ADDRESS OF THE PRESIDENT. XLV particular subject or subjects to which it relates. This last has very properly much weight ; in fact, it has much more weight than one might suppose, if he judged from some criticisms made upon the work of some of our bureaus whose work is more or less scientific. In these criticisms it is urged that the work has not been properly planned and correlated; that it should not be left within the power of one man to say what should be done ; that the plans for work should be prepared by disinterested scientific men—as, for instance, by a committee of the National Academy—and that the function of the bureau official should be executive only. I have seen a good deal of this kind of literature within the last ten or twelve years, and some of the authors of it are very distin- guished men in scientific work; yet I venture to question the wis- dom of such suggestions. As a rule, the plans for any extended scientific work to be undertaken by a Government department are the result of very extended consultations with specialists, and meet with the approval of the majority of them. Were it otherwise the difficulties in obtaining regular annual appropriations for such work would be great and cumulative, for in a short time the disapproval of the majority of the scientific public would make itself felt in Congress. It is true that the vis inertias of an established bureau is very great. The heads of Departments change with each new administration, but the heads of bureaus remain ; and if an unfit man succeeds in obtaining one of these positions, it is a matter of great difficulty to displace him ; but it seems to me to be wiser to direct the main effort to getting right men in right places rather than to attempt to elaborate a system which shall give good results with inferior men as the executive agents, which attempt is a waste of energy. You are all familiar with the results of the inquiry which has been made by a Congressional committee into the organization and work of certain bureaus which are especially connected with scien- tific interests, and with the different opinions which this inquiry has brought out from scientific men. I think that the conclusion of the majority of the committee, that the work is, on the whole, being well done, and that the people are getting the worth of their money, is generally assented to. True, some mistakes have been made, some force has been wasted, some officials have not given satisfac- tion; but is it probable that any other system would give so much better results that it is wise to run the risks of change? XLVI PHILOSOrniCAL SOCIETY OF WASHINGTON. This question brings us to the only definite proposition which has been made in this direction, namely, the proposed Department of Science, to which all the bureaus whose work is mainly scientific, such as the Coast Survey, the Geological Survey, the Signal Service, the Naval Observatory, etc., shall be transferred. The arguments in favor of this are familiar to you, and, as re- gards one or two of the bureaus, it is probable that the proposed change would effect an improvement ; but as to the desirability of centralization and consolidation of scientific interests and scientific work into one department under a single head, I confess that I have serious doubts. One of the strongest arguments in favor of such consolidation that I have seen is the address of the late president of the Chemical Society of Washington, Professor Clarke, " On the Re- lations of the Government to Chemistry," delivered about a year ago. Professor Clarke advises the creation of a large, completely- equipped laboratory, planned by chemists and managed by chemists, in which all the chemical researches required by any department of the Government shall be made, and the abandonment of individual laboratories in the several bureaus on the ground that these last are small, imperfectly equipped, and not properly specialized ; that each chemist in them has too broad a range of duty and receives too small a salary to command the best professional ability. He would have a national laboratory, in which one specialist shall deal only with metals, another with food products, a third with drugs, etc., while over the whole, directing and correlating their work, shall preside the ideal chemist, the all-round man, recognized as the leader of the chemists of the United States. And so should the country get better and cheaper results. It is an enticing plan and one which might be extended to many other fields of work. Grant- ing the premises that we shall have the best possible equipment, with the best possible man at the head of it, and a sufficient corps of trained specialists, each of whom will contentedly do his own work as directed and be satisfied, so that there shall be no jealousies, or strikes, or boycotting, and we have made a long stride toward Utopia. But before we centralize in this Avay we must settle the question of classification. Just as in arranging a large library there are many books Avhich belong in several different sections, so it is in applied science. Is it certain that the examination of food products or of drugs should be made under the direction of the national ANNUAL ADDRESS OP THE PRESIDENT. XLVII chemist rather than under that of the Departments which are most interested in the composition and quality of these articles ? This does not seem to me to be a self-evident proposition by any means. The opinion of a scientific man as to whether the Government should or should not undertake to carry out any particular branch of scientific research and publish the results, whether it should attempt to do such work through officers of the Army and Navy, or more or less exclusively through persons specially employed for the pur- pose, whether the scientific work shall be done under the direction of those who wish to use, and care only for, the practical results, or whether the scientific man shall himself be the administrative head and direct the manner in which his results shall be applied ; the opinion of a scientific man on such points, I say, will differ accord- ing to the part he expects or desires to take in the work, according to the nature of the work, according to whether he is an Army or Navy officer or not, according to whether he takes more pleasure in scientific investigations than in administrative prob- lems, and so forth. It is necessary, therefore, to apply a correction for personal equa- tion to each individual set of opinions before its true weight and value can be estimated, and, unfortunately, no general formula for this purpose has yet been worked out. I can only indicate my own opinions, which are those of an Army officer, who has all he wants to do, who does not covet any of his neighbors' work or goods, and who does not care to have any more masters than those whom he is at present trying to serve. You see that I give you some of the data for the formula by which you are to correct my statements, but this is all I can do. I am not inclined at present to urge the creation of a department of science as an independent department of the Government having at its head a Cabinet officer. Whether such an organization may become expedient in the future seems to me doubtful ; but at all events I think the time has not yet come for it. I do not believe that Government should undertake scientific work merely or mainly because it is scientific, or because some useful results may possibly be obtained from it. It should do, or cause to be done, such scientific work as is needful for its own in- formation and guidance when such work cannot be done, or cannot be done so cheaply or conveniently, by private enterprise. Some kinds of work it can best have done by private contract, and not by XLVIII PHILOSOPHICAL SOCIETY OF WASHINGTON. officials ; others, by its own officers. To this last class belong those branches of scientific investigation, or the means for promoting them, which require long-continued labor and expenditure on a uniform plan—such as the work of the Government Observatory, of the Government surveys, of the collection of the statistics which are so much needed for legislative guidance, and in which we are at present so deficient, the formation of museums and libraries, and so forth. Considering the plans and operations of these Government insti- tutions from the point of view of the scientific public, it is highly desirable that they should contribute to the advancement of abstract science, as well as to $he special practical ends for which they have been instituted ; but from the point of view of the legislator, who has the responsibility of granting the funds for their support, the practical results should receive the chief consideration, and there- fore they should be the chief consideration on the part of those who are to administer these trusts. It must be borne in mind that while the average legislator is, in many cases, not qualified to judge a priori as to what practical results may be expected from a given plan for scientific work, he is, nevertheless, the court which is to decide the question according to the best evidence which he can get, or, rather, which is brought before him, and it is no unimportant part of the duty of those who are experts in these matters to fur- nish such evidence. But in saying that practical results should be the chief considera- tion of the Government and of its legislative and administrative agents it is not meant that these should be the only considerations. In the carrying out of any extensive piece of work which involves the collection of data, experimental inquiry, or the application of scientific results under new conditions there is more or less oppor- tunity to increase knowledge at the same time and with compara- tively little increased cost. Such opportunity should be taken ad- vantage of, and is also a proper subsidiary reason for adopting one plan of work in preference to another, or for selecting for appoint- ment persons qualified not only to do the particular work which is the main object, but also for other allied work of a more purely scientific character. On the same principle it seems to me proper and expedient that when permanent Government employees have at times not enough to do in their own departments, and can be usefully employed in ANNUAL ADDRESS OF THE PRESIDENT. XLIX scientific work, it is quite legitimate and proper to thus make use of them. For example, it is desirable that this country should have such an organization of its Army and Navy as will permit of rapid expansion when the necessity arises, and this requires that more officers shall be educated and kept in the service than are needed for military and naval duty in time of peace. It has been the policy of the Government to employ some of these officers in work connected with other departments, and especially in work which requires such special training, scientific or administrative, or both, as such officers possess. To this objections are raised, which may be summed up as follows : First, that such officers ought not to be given positions which would otherwise be filled by civilian scientists, because these places are more needed by the civilians as a means of earning subsistence, and because it tends to increase the competition for places and to lower salaries. Put in other words, the argument is that it is in- jurious to the interests of scientific men, taken as a body, that the Government should employ in investigations or work requiring special knowledge and skill men who have been educated and trained at its expense, and who are permanently employed and paid by it. This is analogous to the trades union and the anti-convict labor platforms. The second objection is that Army and Navy officers do not, as a rule, possess the scientific and technical knowledge to properly per- form duties lying outside of the sphere of the work for which they have been educated, and that they employ as subordinates really skilled scientific men, who make the plans and do most of the work, but do not receive proper credit for it. The reply to this is that it is a question of fact in each particular case, and that if the officer is able to select and employ good men to prepare the plans and to do the work, this in itself is a very good reason for giving him the duty of such selection and employment. A third objection is that when an officer of the Army or Navy is detailed for scientific or other special work the interests of this work and of the public are too often made subordinate to the interests of the naval or military service, more especially in the matter of change of station. For example, civil engineers object to the policy of placing river and harbor improvements in the hands of Army engineers, because one of the objects kept in view by the War Department in making details for this purpose is to vary the L PHILOSOPHICAL SOCIETY OF WASHINGTON. duty of the individual officer from time to time so as to give him a wider experience. Hence it may happen that all officer placed on duty in connection with the improvement of certain harbors on the Great Lakes shall, after three or four years, and just as he has gained sufficient experience of the peculiarities of lake work to make his supervision there peculiarly valuable, be transferred to work on the improvement of the Lower Mississippi with which he may be quite unfamiliar. In like manner Professor Clarke objects to having a labora- tory connected with the medical department of the Navy on the ground that the officer in charge is changed every three years ; consequently science suffers in order that naval routine may be pre- served. There is force in this class of objections, but the moral I should draw from them is, not that Army and Navy officers should not be allowed to do work outside their own departments or in science, but that when they are put upon such duty, the ordinary routine of change of station every three or four years should not be enforced upon them without careful consideration of the circumstances of the case, and satisfactory evidence that the work on which they are en- gaged will not suffer by the change. And, as a matter of fact, I believe this has been the policy pursued, and instances could be given where an officer has been kept twenty years at one station for this very reason. I pass over a number of objections that I have heard made to the employment of Army and Navy officers as administrators, on the ground that they are too " bumptious," or " domineering," or "super- cilious," or " finicky," because every one knows what these mean and their force. An Army officer is not necessarily a polished gentleman ; neither is a civilian; and a good organizer and administrator, whether officer or civilian, will at times, and especially to some people, appear arbitrary and dictatorial. There is another objection to special details of Army or Navy officers for scientific duties which comes not so much from outside persons as from the War Department and the officers themselves, and it is this : Among such officers there are always a certain num- ber who not only prefer special details to routine duty, but who actively seek for such details, who are perpetual candidates for them. The proportion of men whose ideas as to their own scientific ac- ANNUAL ADDRESS OF THE PRESIDENT. LI quirements, merits, and claims to attention are excessive as com- pared with the ideas of their acquaintances on the same points is not greater in the Army than elsewhere, but when an Army officer is afflicted in this way the attack is sometimes very severe, and the so-called influence which he brings to bear may cause a good deal of annoyance to the Department, even if it be not sufficient to obtain his ends. I have heard officers of high rank, in a fit of impatience under such circumstances, express a most hearty and emphatic wish that no special details were possible, so that lobbying for them should be useless. This, however, seems to me to be too heroic a remedy for the disease, which, after all, only produces comparatively trifling irritation and discomfort. The same evil exists, to a much greater extent, in the civil branches of the Government. Few persons can fully appreciate the loss of time, the worry, and the annoyance to which the respon- sible heads of some of our bureaus for scientific work are subjected through the desire of people for official position and for mainte- nance by the Government. They have to stand always at the bat and protect their wickets from the balls which are bowled at them in every direction, even from behind by some of their own subor- dinates. It is true that a great majority of the balls go wide and cause little trouble, and a majority of the bowlers soon get tired and leave the field, but there are generally a few persistent ones who gradually acquire no small degree of skill in discovering the weak or unguarded points, and succeed in making things lively for a time. Considered from the point of view of the public interests, such men are useful, for although they cause some loss of valuable time, and occasionally do a little damage by promoting hostile legislation, yet their criticisms are often worth taking into account ; they tend to prevent the machine from getting into a rut, and they promote activity and attention to business on the part of administrative chiefs. It is a saying among dog fanciers that a few fleas on a dog are good for him rather than otherwise, as they compel him to take some exercise under any circumstances. At all events I think it very doubtful whether the jealousies and desire for position for one's self or one's friends which exist under present circumstances would be materially diminished under any other form of organization, even under a department of science. Some conflict of interests now exists it is true ; some work is dupli- LII PHILOSOPHICAL SOCIETY OF WASHINGTON. cated ; but neither the conflict nor the duplication are necessarily wholly evil in themselves, nor in so far as they are evil are they necessary parts of the present system. This system is of the nature of a growth ; it is organic and not a mere pudding-stoue aggrega- tion of heterogeneous materials, and the wise course is to correct improper bendings and twistings gradually, prune judiciously, and go slow in trying to secure radical changes lest death or permanent deformity result. It will be seen that in what I have said I have not attempted to eulogize science or scientists in the abstract. I should be very sorry, however, to have given any one the impression that I think they should not be eulogized. Having read a number of eloquent tributes to their importance by way of inducing a proper frame of mind in which to prepare this address, it is possible that I overdid it a little, and was in a sort of reaction stage when I began to write. But the more I have thought on the subject, and the more care- fully I have sought to analyze the motives and character of those of my acquaintances who are either engaged in scientific work or who wish to be considered as so doing, and to compare them with those who have no pretensions to science, and who make none, the more I have been convinced that upon the Avhole the eulogium is the proper thing to give, and that it is not wise to be critical as to the true inwardness of all that we see or hear. At least nine-tenths of the praises which have been heaped upon scientific men as a body are thoroughly well deserved. Among them are to be found a very large proportion of true gentlemen, larger, I think, than is to be found in any other class of men—men char- acterized by modesty, unselfishness, scrupulous honesty, and truth- fulness, and by the full performance of their family and social duties. Even their foibles may be likable. A little vanity or thirst for publicity, zeal in claiming priority of discovery, or undue wrath over the other scientist's theory, does not and should not detract from the esteem in which we hold them. A very good way of viewing characteristics which we do not like is to bear in mind that different parts of the brain have different functions ; that all of them cannot act at once, and that their tendencies are sometimes contradictory. There are times when a scientific man does not think scientifically, when he does not want to so think, and possibly when it is best that he should not so think. There is wisdom in Sam. Lawson's remark ANNUAL ADDRESS OF THE PRESIDENT. LIII that " Folks that are always telling you what they don't believe are sort o' stringy and dry. There ain't no 'sorption got out o' not be- lieving nothing." At one time the emotional, at another the intel- lectual, side of the scientific man has the ascendency, and one must appeal from one state to the other. Were scientific thinking rigor- ously carried out to practical results in every-day life there would be some very remarkable social changes, and perhaps some very disagreeable ones. That scientific pursuits give great pleasure without reference to their utility, or to the fame or profit to be derived from them ; that they tend to make a man good company to himself and to bring him into pleasant associations is certain ; and that a man's own pleasure and happiness are things to be sought for in his work and companionship is also certain. If in this address I have ventured to hint that this may not be the only, nor even the most important, object in life, that one may be a scientific man, or even a man of science, and yet not be worthy of special reverence ; because he may be at the same time an intensely selfish man, and even a vicious man, I hope that it is clearly understood that it is with no inten- tion of depreciating the glory of science or the honor which is due to the large number of scientific gentlemen whom I see around me. A scientific gentleman—all praise to him who merits this title — it is the blue ribbon of our day. We live in a fortunate time and place; in the early manhood of a mighty nation, and in its capital city, which every year makes more beautiful, and richer in the treasures of science, literature, and art which all the keels of the sea and the iron roads of the land are bringing to it. Life implies death ; growth presages decay ; but we have good reasons for hoping that for our country and our people the evil days are yet far off. Yet we may not rest and eat lotus ; we may not devote our lives to our own pleasure, even though it be pleasure derived from scientific investigation. No man lives for himself alone ; the scientific man should do so least of all. There never was a time when the world had more need of him, and there never was a time when more care was needful lest his torch should prove a firebrand and destroy more than it illuminates. The old creeds are quivering; shifting; changing like the colored flames on the surface of the Bessemer crucible. They are being analyzed, and accounted for, and toned down, and explained, until many are doubting whether there is any solid substratum beneath LIV PHILOSOPHICAL SOCIETY OF WASHINGTON. but the instinct which gave those creeds their influence is un- changed. The religions and philosophies of the Orient seem to have little in common with modern science. The sage of the east did not try- to climb the ladder of knowledge step by step. He sought a wisdom which he supposed far superior to all knowledge of earthly phenomena obtainable through the senses. The man of science of the west seeks knowledge by gradual accumulation, striving by comparison and experiment to eliminate the errors of individual observations, and doubting the possibility of attain- ing wisdom in any other way. The knowledge which he has, or seeks, is knowledge which may be acquired partly by individual effort and partly by co-operation, which requires material resources for its development, the search for which may be organized and pursued through the help of others, which is analogous in some respects to property which may be used for power or pleasure. The theologian and the poet claim that there is a wisdom which is not acquired but attained to, which cannot be communicated or received at pleasure, which comes in a way vaguely expressed by the words intuition or inspiration, which acts through and upon the emotional rather than the intellectual faculties, and which, thus acting, is sometimes of irresistible power in exciting and directing the actions of individuals and of communities. The answer of the modern biologist to the old Hebrew question, viz., " Why are children born with their hands clenched while men die with their hands wide open?" would not in the least resemble that given by the Rabbis, yet this last it is well that the scientist should also remember : " Because on entering the world men would grasp everything, but on leaving it all slips away." There exist in men certain mental phenomena, the study of which is included in what is known as ethics, and which are usually assumed to depend upon what is called moral law. Whether there is such a law and whether, if it exists, it can be logically deduced from observed facts in nature or is only known as a special revelation, are questions upon which scientific men in their present stage of development are not agreed. There is not yet any satisfactory scientific basis for what is recognized as sound ethics and morality throughout the civil- ized world ; these rest upon another foundation. This procession, bearing its lights of all kinds, smoky torches, clear-burning lamps, farthing rush-lights, and sputtering brimstone ANNUAL ADDRESS OF THE PRESIDENT. LV matches, passes through the few centuries of which we have a record, illuminating an area which varies, but which has been grow- ing steadily larger. The individual members of the procession come from, and pass into, shadow and darkness, but the light of the stream remains. Yet it does not seem so much darkness, an infinite night, whence Ave come and whither we go, as a fog which at a little dis- tance obscures or hides all things, but which, nevertheless, gives the impression that there is light beyond and above it. In this fog we are living and groping, stumbling down blind alleys, only to find that there is no thoroughfare, getting lost and circling about on our own tracks as on a jumbie prairie; but slowly and irregularly we do seem to be getting on, and to be establishing some points in the survey of the continent of our own ignorance. In some directions the man of science claims to lead the way; in others the artist, the poet, the devotee. Far reaching as the specu- lations of the man of science may be, ranging from the constitution and nature of a universal protyle, through the building of a universe to its resolution again into primal matter or modes of motion, he can frame no hypothesis which shall explain consciousness, nor has he any data for a formula which shall tell what becomes of the in- dividual when he disappears in the all-surrounding mist. Does he go on seeking and learning in other ways or other worlds ? The great mass of mankind think that they have some information bear- ing on these questions ; but, if so, it is a part of the wisdom of the Orient, and not of the physical or natural science of the Occident. Whether after death there shall come increase of knowledge, with increase of desires and of means of satisfying them, or whether there shall be freedom from all desire, and an end of coming and going > we do not know; nor is there any reason to suppose that it is a part of the plan of the universe that we should know. We do know that the great majority of men think that there are such things as right and duty—God and a future life—and that to each man there comes the opportunity of doing something which he and others recognize to be his duty. The scientific explanation of a part of the process by which this has been brought about, as by natural selection, heredity, education, progressive changes in this or that particular mass of brain matter, has not much bearing on the practical ques- tion of " What to do about it ? " But it does, nevertheless, indicate that it is not a characteristic to be denounced, or opposed, or neg- lected, since, even in the " struggle-for-existence " theory, it has I LVI PHILOSOPHICAL SOCIETY OF WASHINGTON. been, and still is, of immense importance in human social develop- ment. " Four men," says the Talmud, " entered Paradise. One beheld and died. One beheld and lost his senses. One destroyed the young plants. One only entered in peace and came out in peace." Many are the mystic and cabalistic interpretations which have been given of this saying ; and if for " Paradise " we read the " world of knowl- edge " each of you can no doubt best interpret the parable for him- self. Speaking to a body of scientific men, each of whom has, I hope, also certain unscientific beliefs, desires, hopes, and longings, I will only say : " Be strong and of a good courage." As scientific men, let us try to increase and diffuse knowledge ; as men and citi- zens, let us try to be useful ; and, in each capacity, let us do the work that comes to us honestly and thoroughly, and fear not the unknown future. When we examine that wonderful series of wave marks which we call the spectrum we find, as we go downwards, that the vibrations become slower, the dark bands wider, until at last we reach a point where there seems to be no more movement ; the blackness is con- tinuous, the ray seems dead. Yet within this year Langley has found that a very long way lower down the pulsations again appear, and form, as it were, another spectrum ; they never really ceased, but only changed in rhythm, requiring new apparatus or new senses to appreciate them. And it may well be that our human life is only a kind of lower spectrum, and that, beyond and above the broad black band which we call death, there are other modes of impulses—another spectrum—which registers the ceaseless beats of wTaves from the great central fountain of force, the heart of the universe, in modes of existence of which we can but dimly dream. BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. GENERAL MEETING. 0) BULLETIN GENERAL MEETING. 279th Meeting. January 16, 1886. President Billings in the Chair. Thirty-two members and guests present. Announcement was made of the election to membership of Messrs. Benjamin Pickman Mann and Charles Cooper Nott. The following report of the Auditing Committee was presented by its chairman, Mr. Toner : December 24, 1885. The undersigned, a committee appointed at the annual meeting of the Philosophical Society of Washington, December 19, 1885, for the purpose of auditing the accounts of the Treasurer, beg leave to report as follows : We have examined the statement of receipts, including annual dues, sale of Bulletin, and interest on bonds, and find the same to be correct as stated. We have examined the statement of disbursements, and com- pared the same with the vouchers, and find them to agree. We have examined the returned checks and the bank account with Puggs & Co., and find the balance, $484.02, to agree with the statements in the Treasurer's report. We have examined the U. S. bonds belonging to the Society, and find them to be in amount and character as represented in the Treasurer's report, aggregating $2,500. J. M. Toner, O. T. Mason, T. C. Mendenhall, Committee. (3) 4 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. J. S. Diller communicated NOTES ON THE GEOLOGY OF NORTHERN CALIFORNIA. [Abstract.] Under the direction of Capt. Dutton I have spent the last three summers studying the geology of northern California and the ad- jacent portion of Oregon. The conclusions of a general nature referring to that region may be briefly summarized as follows : In the northern end of the Sierra Nevada and the central por- tion of the Coast range, among the highly plicated, more or less metamorphosed strata which are older than those of the Chico group, there appears to be but one horizon of limestone, and that is of Car- boniferous age. The northern end of the Sierra Nevada is made up of three tilted orographic blocks which are separated from each other by great faults. The westernmost of these blocks stretching far to the southeast appears to form the greater portion of the range. As in the Great Basin region the depressed side of each block was occupied by a body of water of considerable size. The deposits formed in these lakes gave rise to the fertile soils of American and Indian valleys. The plication of the strata in the Sierra Nevada range took place, at least in great part, about the close of the Jurassic or beginning of the Cretaceous period, but the faulting which really gave birth to the Sierra as a separate and distinct range by differentiating it from the great platform stretching eastward into the Great Basin region, did not take place until towards the close of the Tertiary or the beginning of the Quaternary. Although the faulting may have commenced earlier, the greater portion of the displacement has taken place since the deposition of a large part of the auriferous gravels and the beginning of the great volcanic outbursts in the vicinity of Lassen's Peak. If we may accept numerous small earthquake shocks as evidence, the faulting still continues. The distribution of the rocks of the Chico group indicates that the western coast of the continent at that time lay along the western base of the Sierra extending around the northern end of the range in the vicinity of Lassen's Peak and stretching far northeasterly into Oregon.. Off the coast lay a large island which now forms GENERAL MEETING. 5 northwestern California and the adjacent portion of Oregon. This island extended as far southeast as the Pit river region where it was separated from the main land by a wide strait. All of the ridges developed out of the Cretacean island belong to the Coast range. The volcanic ridge of Lassen's Peak lies between the northern end of the Sierra Nevada and the Coast range. The great volcanic field of Oregon and Washington Territory, to which Lassen's Peak and the Cascade range belong, appears in a general way to be out- lined by the depression between the Cretacean island and the main land. A general account of the facts from which these conclusions are drawn will appear in Bulletin of the U. S. Geological Sur- vey No. 33. Mr. I. C. Russell read a supplementary paper entitled NOTES ON THE FAULTS OF THE GREAT BASIN AND OF THE EASTERN BASE OF THE SIERRA NEVADA. [Abstract.] The structure of the Great Basin was systematically studied by the geologists of the Fortieth Parallel Exploration, and subsequently by G. K. Gilbert and J. W. Powell. The results of these investiga- tions, so far as they relate to the faults of the region, are indicated in the bibliographic list which follows. The studies here referred to led to the recognition of a type of mountain structure named the " Great Basin system," which has been found to prevail over large portions of the United States west of the Rocky Mountains. A typical mountain of this system is a long, narrow orographic block, upraised along one edge, i. e. a mono- clinal ridge. A mountain range having this structure usually presents an abrupt scarp, formed of the edges of broken strata, on -the side bordered by the fault, and slopes much more gently in the opposite direction. Mountain ranges of this character occupy the greater part of the area of interior drainage, known as the Great Basin, and at times overlap its borders. An older structure in which corrugation plays an important part has been recognized by several geologists in the desert ranges of Nevada and Utah, but these disturbances were produced previous to the faulting which gave origin to the present topographic relief. 6 PHILOSOPHICAL SOCIETY OF WASHINGTON. The writer has observed Great Basin structure to extend through- out Western Utah, Northern Nevada, and into' Oregon as far as Malheur Lake. On the west side of the Great Basin, at the imme- diate base of the Sierra Nevada, there is an immense compound displacement that can be followed all the way from Honey Lake on the north to beyond Owen's Lake on the south, a distance of over 350 miles. Along many of the faults composing this belt the records of a post-Quaternary movement may be clearly recognized. Fault scarps produced by recent movement have been observed in Eagle and Carson Valleys, south of Carson City, in Bridgeport Valley, and on the west side of Mono Lake. The earthquake in Owen's Valley in 1872, was caused by a movement along one of the faults of this series. The eastern face of the Sierra Nevada is extremely abrupt and its western slope is gentle. Corrugations of older date than the faults which determine the present relief of the mountains may be observed at many localities. It thus agrees in its general features with many of the Basin ranges. The Sierra Nevada is essentially monoclinal in structure, but is traversed from north to south by faults which divide it into separate ranges, as may be seen in the neighborhood of Lake Tahoe and in the elevated region west of Mono Lake. The Great Basin structure here extends beyond the borders of the area of interior drainage, and is probably limited on the west by the great valley of California. How far north of Lake Tahoe the secondary faults that divide the mountain mass may be traced is unknown, but they can certainly be followed to where the Central Pacific railroad crosses the mountains. The following list indicates where observations on the faults of the Great Basin system may be found : Clarence King: Reports of the Fortieth Parallel Exploration. Vol. 1, 1878, pp. 735, 744-746; Vol. Ill, 1870, p. 451. J. D. Whitney : The Owens Valley earthquake. Overland Monthly, Aug. and Sept., 1872. Joseph Le Conte: On the Structure and Origin of Mountains, with special reference to recent objections to the "Contraction Theory." American Journal of Science, Vol. XVI, '1878, pp. 95-112. u " A theory of the formation of the great features of the earth's crust. American Journal of Science, Vol. IV, 1872, pp. 345-355, 460-472. GENERAL MEETING. 7 G. K. Gilbert : Progress report upon Geographical and Geological Explorations and Surveys West of the 100th Meridian, in 1872. Washington, 1874. p. 50. " " Report upon Geographical and Geological Explo- rations and Surveys west of the 100th Meri- dian. Washington, 1875. Vol. Ill, Geology, pp. 21-42. " " Contributions to the history of Lake Bonneville. In Second Annual Report of the U. S. Geo- logical Survey. Washington, 1882. pp. 192 -200. " " A theory of the earthquakes of the Great Basin with a practical application. American Journal of Science, Vol. XXVII, 1884, pp. 49-53. J. W. Powell : Basin Range System. See Report on Lands of the Arid Region of the United States. Washington, 1879. pp. 94-95. " " Basin Range Province. See Report on the Geology of the eastern portion of the Uinta Mountains. Washington, 1876. pp. 6-7, 23- 25. C. E. Dutton : Geology of the High Plateaus of Utah. Washing- ton, 1880. pp. 51-53. I. C. Russell : Sketch of the Geological History of Lake Lahon- tan. Third Annual Report of the U. S. Geological Survey. Washington, 1883. p. 202. " " A Geological Reconnoissance in Southern Oregon. Fourth Annual Report of the U. S. Geologi- cal Survey. Washington, 1884. pp. 442-453. " " Lake Lahontan. Monograph No. XI, U. S. Geological Survey, pp. 24-28, 274-284. Mr. Gilbert remarked that the section exhibited by Mr. Diller appeared to demonstrate a history comprising (1) the folding of the slates and the formation of several faults and associated monoclines, (2) the general degradation of the country until the monoclinal ridges were approximately obliterated, and (3) a re- newal of movement on the old fault lines, giving rise to the exist- ing topography. 8 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. Willis remarked that in 1883 he had had opportunity to study the Cascade Mountains north of the region described by Mr. Diller. The Sierra structure is apparently not found in the north- ern part of Washington Territory, and the eastern face of the Cascade range is probably not characterized like the Sierra by a great fault. Mr. Diller concurred in the statement that the Cascade range is built essentially of igneous rocks, and is not characterized by great faults, at least along its eastern base. The topography of the Sierra has entirely changed since the deposition of the auriferous gravels, and some of the fault move- ments are so recent that the stream terraces to which they have given rise are still preserved. Mr. G. K. Gilbert made a communication on RECENT CHANGES OF LEVEL IN THE BASIN OF LAKE ONTARIO. [The substance of this communication was presented to the American Association for the Advancement of Science at Ann Arbor, and appears in abstract in Science, Vol. VI, p. 222.] Remarks were made by Mr. E. Farquhar. 280th Meeting. January 30, 1886 The President in the Chair. Fifty-five members and guests present. The Chair announced the appointment of the Committee on Communications. Mr. George E. Curtis made a communication on lieutenant lockwood's expedition to farthest north. [Abstract.] The paper opened with a reference to the statement in the Ency- clopaedia Britannica (article, Polar Regions, p. 326,) that " all this region [the northern coast of Greenland and the interior of Grinnell GENERAL MEETING. 9 Land] had already been explored and exhaustively examined by the English expedition of 1875-76." A refutation of this state- ment was not now necessary inasmuch as a retraction had already been made ; but an impartial examination of Lieut. Lockwood's observations was still required as a basis for our own confidence in the latitude attained. A description of the equipment of the expedition was given, with a sketch of the events of the journey, and extracts from the narra- tive report. The weights of the food and equipments drawn by the dog team furnished the basis of a discussion as to the value of dogs in arctic sledging. The weight of food taken for the support of each man was about twice that taken for each dog. Now if a man can drag a sufficiently greater amount to compensate for the greater weight of his food, it is immaterial whether the motive force used be dogs or men. On this expedition the dog sledge was actually loaded so as to give a weight of about 100 lbs. to each dog ; but the maximum weight that can be advantageously drawn by a man is only 125 or, perhaps, 150 lbs. The ratio of effective work performed to the weight of food consumed is, therefore, materially greater for dogs than for men, so that a substantial economical advantage is obtained by using dogs instead of men for sledge dragging. This advantage seems not to have been appreciated by the English ex- pedition of 1875'-76, whose heavy sledges and equipments were all drawn by hand. In addition to the more conspicuous causes of the failure of Lieut. Beaumont's expedition on the Greenland coast, the neglect to make use of dogs must be added as an important element. The sextant observations made by Lieut. Lockwood for determin- ing the position of his farthest north were shown to be highly satisfactory. Sets of circum-meridian observations for latitude were made at midnight of May 14th and at noon of May 15th. The conditions of observation offer no sufficient reason for giving more weight to one set than to the other. The mean of these results gives 83° 24' as the latitude attained by Lieut. Lockwood, and an uncertainty not greater than 1' represent the accuracy of its deter- mination. The paper closed with the following tribute to the character of Lieut. Lockwood as an arctic explorer : I cannot close this review of Lieut. Lockwood's expedition to farthest north without turning from the cold discussion of the astro- 10 PHILOSOPHICAL SOCIETY OP WASHINGTON. nomical and geographical records to speak of him of whose life and labors they constitute an imperishable memorial.' The success of the expedition was not the result of chance, but was due to Lieut. Lockwood's thorough knowledge of the details of such an undertaking, and to his indomitable energy in its execu- tion. During the preceding winter he had devoted himself to preparation for the work; had made a careful study of the man- agement and equipment of previous sledging expeditions—especially those of the English in 1875-76—and profiting by the experience of his predecessors was able to avoid their mistakes. Lieut. Beau- mont's journey on the Greenland coast was impeded by the heavy sledge, and the heavier equipments with which it was weighted. Lieut. Lockwood's extraordinary distance was attained with a light sledge drawn by dogs and loaded with nothing but food and the barest necessities of a camp. Regardless of all personal comforts, everything was sacrificed to the objects of the expedition. Under the instruction of Mr. Israel, the young astronomer* Lieut. Lockwood had familiarized himself during the winter with all the astronomical observations necessary to be made by an ex- plorer, and with the return of the spring sun applied himself to practical observations with the sextant until he became an expert in its use. So good was his astronomical work that the accuracy of his observations is dependent only on the variability of the in- strument and the difficulty of the conditions of observation. In addition to a practical knowledge of arctic sledging, the expe- dition was undertaken with a determined energy of purpose, those qualities expressively termed " grit" and " pluck," which no obstacle could defeat. Retaining only two companions at Cape Bryant, he sent back his supporting party and continued his advance over an unknown coast. Suffering continuously from cold, hunger, or fatigue, he pushed on with unflinching perseverance until one hun- dred and fifty miles of new coast were traversed and the national colors unfurled in the highest latitude ever attained by man. Simply to go a little nearer the pole than his predecessors was not, however, the controlling object of this expedition. Lieut. Lockwood's own motives, as we read them in his journal, were these: "My great wish is to accomplish something on the north coast of Greenland that will reflect credit on myself and on the ex- pedition." Inspired by this praiseworthy ambition, his skillful management resulted in its most successful realization. His mo- GENERAL MEETING. 11 tives were not those of the visionary and enthusiast who " knows nothing and fears nothing," but of an earnest practical explorer whose ambition is to add something to the world's knowledge of the planet on which we live. The literal fidelity of his narrative, its freedom from an exaggeration that has too often marred the records of previous Arctic explorers, the exact and painstaking descriptions, and the careful distinction between what is seen and what is inferred, all bear witness to his conscientiousness in the search for truth. As an important element in the success of Lieut. Lockwood's ex- peditions, due recognition must be given to the cordial, sympathetic and able co-operation of Sergeant Brainard. Chosen by Lieut. Lockwood to continue the journey to Cape Bryant, when all the remainder of the party returned, it was Brainard who pushed onward with him over one hundred and fifty miles of that desolate coast and reached the farthest north. It was likewise Lockwood and Brainard who a year later, in May, 1883, explored the interior of Grinnell Land and looked out on the shores of the western polar sea. But only one of these companions in exploration was destined .to reach home to receive the honor due to their heroic achieve- ments—honor due, but, as yet, awarded neither to the living nor the dead. The story of the return is known to all, but perhaps not Lieut. Lockwood's wonderful cheerfulness of spirit through that last terrible winter at Cape Sabine with death staring him in the face Lieut. Lockwood died on April 9, 1884, "from action of water on the heart induced by insufficient nutrition "—the official euphemism for starvation. This record of indescribable suffering, privation and death, following that of two years of heroic endeavor and achievement, is a tragedy which appeals to human hearts with, a force unequalled by any story of fiction or by any drama of the stage. To Lieut. Lockwood's achievements are applicable the familiar lines of Horace : " Exegi rnonumentum aere perennius Regalique situ pyramidum altius, Quod non imber edax, non Aquilo impotens Possit diruere, aut innumerabilis Annorum series et fuga temporum." Woven into the history of arctic discovery and engraven on our 12 PHILOSOPHICAL SOCIETY OF WASHINGTON. maps, the substantial results of Lieut. Lockwood's explorations form a tablet more enduring than brass, which the corroding storm, the fierce north wind, and the flight of ages cannot efface. In reply to a question by Mr. Mussey, Mr. Curtis stated that the time for longitude determination was obtained from one ordinary watch of good quality, and one pocket chronometer. Messrs. Dall and Robinson discussed the advantages and disadvantages of the use of dogs in arctic sledging, and attention was called to the im- portance of using snow shoes, and of coating the sledge runners with ice. Mr. O. T. Mason made a communication on TWO EXAMPLES OF SIMILAR INVENTIONS IN AREAS WIDELY APART. [Abstract.] Anthropologists assign similar inventions observed in different parts of the world to one of the following causes : 1. The migration of a certain race or people who made the in- vention. Upon this theory similar inventions argue the presence of the same people or race. 2. The migration of ideas—that is, an invention may be made by a certain race or people and taught or loaned to peoples far removed in time and place. Upon this theory similar inventions argue iden- tity of origin, but not necessarily the consanguinity of those who practice them. 3. In human culture, as in nature elsewhere, like causes produce like effects. Under the same stress and resources the same inven- tions will arise. Now, the question arises, which of these causes shall be invoked in specific cases to account for resemblances. We must first examine the word resemblance. Taking Aristotle's four causes : The material cause, ex qua aliquid fit. The formal cause, per quam. The efficient cause, a qua. The final cause, propter quam. We must enlarge upon them as follows : Every human activity involves six fundamental considerations. 1. The agent, or efficient cause. GENERAL MEETING. ' 13 2. The material cause. 3. The implemental cause. 4. The formal cause. 5. The processive cause—that is, the exact order and method of the action. 6. The motive or function. We might, also, include a series of concomitants, such as techni- cal vocabulary, all sorts of traditional lore and myths, social or- ganization, and even religious rites. Again, some of the six causes are themselves generally the out- come of other causes, so that we have concatenations and genealo- gies of causes. Now for the application. Most men, when they say this thing resembles that, have reference only to one of our six causes. They mean simply that there is resemblance in form, or material, or technical method, or function. My plan would be to submit such resemblances to scrutiny to ascertain how far they extend, and, also, to examine resemblances known to be consanguine, or borrowed, or independent, to ascertain which of our characteristics are pecu- liar to them. In that way an inductive system of rules would be adduced. The two independent inventions which I exhibit are a beginning in that direction. One is a stitch in basketry, found only at Cape Flattery and on the Congo. This stitch is common enough in fish- traps, wattling fences, and cages, but in only these two areas have people thought to apply it to close basketry. It consists of vertical warp, a horizontal second warp, laid behind the first, and a coiling or sewing of these two together, so as to show a diagonal stitch in front and a vertical stitch in the rear. Here the resemblance is in method alone. In all other respects the inventions diner. The other invention referred to is the throwing-stick of Austra- lians, Puru Purus, and Eskimo. These agree, in motive or func- tion and in the fundamental idea of a staff and a hook. Beyond this the Eskimo have invented a dozen additional attachments never dreamed of by the others. Mr. Murdoch supplemented the enumeration of throwing sticks by describing an undeveloped form used by the Siberian Eskimo. In reply to a question by Mr. Goode, Mr. Mason stated that he had not seen the Brazilian sticks ; they are mentioned by many 14 PHILOSOPHICAL SOCIETY OF WASHINGTON. travelers. Mr. Mann and Mr. Murdoch described the manner in which the throwing stick is used by Eskimo in kyaks. The motion centers in the wrist and not the elbow or shoulder. 281st Meeting. February 13, 1886. The President in the Chair. Fifty-five members and guests present. Mr. J. H. Kidder communicated an HISTORICAL SKETCH OF DEEP SEA TEMPERATURE OBSERVATIONS, illustrating the subject by numerous diagrams and by a collection of deep sea thermometers. Mr. E. B. Elliott made a communication on the ANNUAL PROFIT TO BANKS OF NATIONAL BANK NOTE CIRCULATION, and a second communication on the QUANTITY OF UNITED STATES SUBSIDIARY SILVER COIN EXISTING AND IN CIRCULATION. In these papers he developed the formulae used in computing cer- tain tables embodied in the report of the Comptroller of the Currency. Remarks were made by Messrs. Mussey and Lawrence. Mr. Asaph Hall read a paper on THE NEW STAR IN THE NEBULA OF ANDROMEDA, giving an historical account of its discovery, growth and decadence. [This paper is printed in the American Journal of Science, 3d se- ries, vol. xxxi, p. 299.] general meeting. 15 282d Meeting. February 27, 1886. The President in the Chair. Fifty-six members and guests present. The Chair announced the election to membership of Mr. George JOTHAM CUMMINGS. Mr. Asaph Hall made a communication on THE IMAGES OF STARS, which was discussed by Messrs. Eastman, Curtis, and Paul. [This paper is published in the Sidereal Messenger, April, 1886.] Mr. R. S. Woodward made a communication ON THE CHANGES OF TERRESTRIAL LEVEL SURFACES DUE TO VARIATIONS IN DISTRIBUTION OF SUPERFICIAL MATTER. [To appear as a Bulletin of the U. S. Geological Survey.] He was followed by Mr. G. K. Gilbert with a paper ON THE OBSERVED CHANGES OF LEVEL SURFACES IN THE BONNE- VILLE AREA, AND THEIR EXPLANATION ; and Mr. T. C. Chamberlin then began a paper ON THE VARYING ATTITUDES OF FORMER LEVEL SURFACES IN THE GREAT LAKE REGION AND THE APPLICABILITY OF PRO- POSED EXPLANATIONS. 283d Meeting. March 13, 1886. Vice-President Harkness in the Chair. Thirty-nine members and guests present. The Secretary read a letter from the Secretary of the Council of the Anthropological Society, inviting the members of the Philo- sophical Society and their friends to attend the annual meeting of 16 PHILOSOPHICAL SOCIETY OF WASHINGTON. the Anthropological Society and listen to an address by its president, Major J. W. Powell. The Chair announced the election to membership of Messrs. Car- los Albert Kenaston, Roland Duer Irving and Artemas Martin. Mr. T. C. Chamberlin completed his communication ON THE VARYING ATTITUDES OF FORMER LEVEL SURFACES IN THE GREAT LAKE REGION AND THE APPLICABILITY OF PROPOSED EXPLANATIONS. Remarks were made by Mr. Dutton. Mr. R. D. Irving made a communication on THE ENLARGEMENT OF MINERAL FRAGMENTS AS A FACTOR IN ROCK ALTERATION, which was discussed by Messrs. Iddings, Diller, Dutton, and Lawrence. 284th Meeting. March 27, 1886. The President in the Chair. Thirty-three members and guests present. Mr. I. C. Russell made a communication on THE SUBAERIAL DECAY OF ROCKS AND THE ORIGIN OF THE RED CLAY OF CERTAIN FORMATIONS. This was discussed by Prof. John S. Newberry, of New York city, and by Messrs. Goode, Darton, Irving, and Chamberlin. Mr. Romyn Hitchcock made a communication on RECENT IMPROVEMENTS IN MICROSCOPIC OBJECTIVES, WITH DEMON- STRATION OF THE RESOLVING POWER OF A NEW 1-16TH INCH. Remarks were made by the President. GENERAL MEETING. 17 Mr. Henry Farquhar read a communication on A FONETIK ^ELFABET. [^Ebstraekt.] Ais selfabet cendoerteyks tu repriz6nt de sawndz av I^glic spiytc sez yuwjuwali hoard, bai twenti-nain letoerz. Av <5iyz b, d, f, g, h, 1c, I, m, n, p, r, s, t, v, w, y send z hsev der koestomeri sawndz ; c hsez its sawnd sez in benificieri [beneficiary] — a sawnd akeyjoenali given tu s or t or ch, or mooer ofen tu sh ; j iz kanfamd tu its Frentc sawnd— hwitc iz ool dset iz left tu it hwen kambaind wi cj cj C p a '2^ * cj c " § S CD **-< *J ® c3T3 t- 03 CO 0J 5 co 03 CJ O °3 m g® ft 3 OO «M —7 cy SO? - 03 all 'S Ih CO Q« CO . bo's oj 0) eS >»« * PQ fto ftH -C'Ho «> CcS mS -S'S'S CJ O CJ (h O CJw o — >-i v^ w _ mm cq .-s o c S3 "2 pq M m H o H S ft H pq pq o g 03 ft o - i i o o o o BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. ANNUAL ADDRESS OF THE PRESIDENT. ANNUAL ADDRESS OF THE PRESIDENT, William Harkness. Delivered December 10, 1887. THE PROGRESS OF SCIENCE AS EXEMPLIFIED IN THE ART OF WEIGHING AND MEASURING. Two centuries ago the world was just beginning to awaken from an intellectual lethargy which had lasted a thousand years. During all that time the children had lived as their parents before them, the mechanical arts had been at a standstill, and the dicta of Aristotle had been the highest authority in science. But now the night of medievalism was approaching its end, and the dawn of modern progress was at hand. Galileo had laid the foundation for accurate clocks by discovering the isochronism of the simple pendulum ; had proved that under the action of gravity light bodies fall as rapidly as heavy ones ; had invented the telescope and with it dis- covered the spots on the sun, the mountains on the moon, the sat- ellites of Jupiter, and the so-called triple character of Saturn ; and after rendering himself immortal by his advocacy of the Copernican system, had gone to his grave, aged, blind, and full of sorrows. His contemporary, Kepler, had discovered the laws which, while history endures, will associate his name with the theory of planetary motion, and he also had passed away. The first Cassini was still a young man, his son was a little child, and his grandson and great-grand- son, all of whom were destined to be directors of the Paris Observa- tory, were yet unborn. The illustrious Huyghens, the discoverer of Saturu's rings and the father of the undulatory theory of light, was in the zenith of his powers. The ingenious Hooke was a little younger, and Newton, towering above them all, had recently in- vented fluxions, and on the 28th of April, 1686, had presented his Principia to the Royal Society of London and given the theory of gravitation to the world. Bradley, who discovered nutation and 44 xxxix XL PHILOSOPHICAL SOCIETY OF WASHINGTON. the aberration of light ; Franklin, the statesman and philosopher, who first drew the lightning from the clouds ; Doilond, the inventor of the achromatic telescope ; Euler, the mathematician who was destined to accomplish so much in perfecting algebra, the calculus, and the lunar theory; Laplace, the author of the Mecanique Celeste ; Rumford, who laid the foundation of the mechanical theory of heat ; Daltou, the author of the atomic theory upon which all chemistry rests ; and Bessel, the greatest of modern astrono- mers—these and others almost as illustrious, whom we cannot even name to-night, were still in the womb of time. Pure science first felt the effects of the new intellectual life and it was more than a century later before the arts yielded to its influ- ence. Then came Hargreaves, the inventor of the spinning-jenny; Arkwright, the inventor of the cotton-spinning frame; Watt, who gave us the condensing steam engine; Jacquard, the inventor of the loom for weaving figured stuffs ; Murdock, the originator of gas lighting; Evans, the inventor of the high-pressure steam engine; Fulton, the father of steam navigation; Trevithick, who ranks very near Watt and Evans in perfecting the steam engine ; and Stephenson, the father of railroads. If now we add the names of those who have given us the telegraph, to wit: Gauss, the emi- nent physicist and the greatest mathematician of the present cen- tury ; Weber, Wheatstone, and Henry—all famous physicists—and Morse, the inventor and engineer ; we have before us the demi-gods who have transformed the ancient into the modern world, given us machinery which has multiplied the productive power of the human race many fold, annihilated time and space, and bestowed upon toiling millions a degree of comfort and luxury which was unknown to kings and emperors of old. The discoveries and inventions of the last two centuries have so far exceeded all others within historic times that we are amply jus- tified in calling this an age of phenomenal progress, and under the circumstances a little self-glorification is pardonable — perhaps even natural. The weekly and monthly records of scientific events which appear in so many newspapers and magazines are the imme- diate result of this, and the great increase of ephemeral scientific literature has led multitudes of educated people to believe that such records represent actual progress. The multiplication of bricks facilitates the building of houses, but does not necessarily ANNUAL ADDRESS OP THE PRESIDENT. XLI improve architecture. Similarly, the multiplication of minor inves- tigations improves our knowledge of details, but rarely affects the great philosophic theories upon which science is founded. The im- portance of human actions is measured by the degree in which they affect human thought, and the only way of permanently affecting scientific thought is by modifying or extending scientific theories. The men who do that are neither numerous, nor do they require weekly paragraphs to record their deeds ; but their names are hon- ored by posterity. Even in this golden age the advance of science is not steady, but is made by spasmodic leaps and bounds. Mere scientific brick making, commonly called progress, is always the order of the day until some genius startles the world by a discovery affecting accepted theories. Then every effort is directed in the new line of thought until it is measurably worked out, and after that brick making again resumes its place. While the progress in two centuries has been immense, the progress in a week or a month is usually almost nil. Optimism has its uses in many departments of human affairs, but science should be cool and dispassionate, having regard only for the truth. To make a trustworthy estimate of the actual state of the whole vast realm of science would be a task beyond the powers of any one man ; but perhaps it will not be amiss to spend the time at our disposal this evening in briefly reviewing the recent progress and present condition of the funda- mental processes upon which the exact sciences rest—I allude to the methods of weighing and measuring. Physical science, deals with many quantities, but they are all so related to each other that almost every one of them can be ex- pressed in terms of three fundamental units. As several systems of such units are possible, it is important to select the most con- venient, and the considerations which guide us in that respect are the following: 1. The quantities selected should admit of very accurate com- parison with other quantities of the same kind. 2. Such comparisons should be possible at all times, and in all places. 3. The processes necessary for making such comparisons should be easy and direct. XLII PHILOSOPHICAL SOCIETY OF WASHINGTON. 4. The fundamental units should be such as to admit of easy defi- nitions and simple dimensions for the various derived units. Scientific men have long agreed that these requirements are best fulfilled by adopting as the fundamental units, a definite length, a definite mass, and a definite interval of time. Length is an element which can be very accurately measured and copied, but it must be defined by reference to some concrete material standard, as for example, a bar of metal, and as all substances expand and contract with changes of temperature, it is necessary to state the temperature at which the standard is correct. A standard of mass, consisting of a piece of platinum, quartz, or other material not easily affected by atmospheric influences, probably fulfills the conditions set forth above better than any other kind of magnitude. Its comparison with other bodies of approximately equal mass is effected by weigh- ing, and as that is among the most exact of all laboratory operations, very accurate copies of the standard can be made, and they can be carried from place to place with little risk of injury. Time is also an element which can be measured with extreme precision. The immediate instruments of measurement are clocks and chronometers, but their running is checked by astronomical observations and the ultimate standard is the rotation of the earth itself. It is important to note that the use of three fundamental units is simply a matter of convenience and not a theoretical necessity, for the unit of mass might be defined as that which at unit distance would generate in a material point unit velocity in unit time ; and thus we should have a perfectly general system of measurement based upon only two fundamental units—namely, those of space and time. Such a system is quite practicable in astronomy, but cannot yet be applied with accuracy to ordinary terrestrial purposes. Ac- cording to the law of gravitation Mass = Acceleration X (Distance)2 and as in the case of the earth we can measure the quantities on the right-hand side of that equation with considerable accuracy, we can satisfactorily determine the earth's mass in terms of the supposed unit. That suffices for the needs of astronomy, but for other scien- tific and commercial purposes a standard of mass having a magni- tude of about a pound is necessary, and as two such masses can be compared with each other from five to ten thousand times more ANNUAL ADDRESS OF THE PRESIDENT. XLIII accurately than either of them can be determined in terms of the supposed unit, three fundamental units are preferable to two. The Chaldeans, Babylonians, Persians, Greeks, and Romans all seem to have had systems of weights and measures based upon toler- ably definite standards, but after the decline of the Roman Empire these standards seem to have been forgotten, and in the beginning of the sixteenth century the human body had so far become the standard of measurement that the units in common use, as for ex- ample, the foot, palm, etc., were frequently taken directly from it. The complete table of measures of length was then as follows : the breadth (not the length) of four barley corns make a digit, or finger breadth; four digits make a palm, (measured across the middle joints of the fingers ;) four palms are one foot ; a foot and a half is a cubit ; ten palms, or two feet and a half, are a step ; two steps, or five feet, are a pace ; ten feet are a perch ; one hundred and twenty-five paces are an Italic stadium ; eight stadia, or one thousand paces, are an Italic mile ; four Italic miles, are a German mile ; and five Italic miles are a Swiss mile. It was then the practice to fur- nish standards of length in books by printing in them lines a foot or a palm long, according to the size of the page, and from these and other data it appears that the foot then used on the continent of Europe had a length of about ten English inches. In England the first attempts at scientific accuracy in matters of measurement date from the beginning of the seventeenth century, when John Greaves, who must be considered as the earliest of the scientific metrologists, directed attention to the difference between the Roman and English foot by tolerably accurate determinations of the former, and also attempted the investigation of the Roman weights. He was followed by Dr. Edward Bernard, who wrote a treatise on ancient weights and measures about 1685, and towards the end of the century the measurements of the length of a degree by Picard and J. D. Cassini awakened the attention of the French to the importance of rigorously exact standards. In considering the progress of science with respect to standards of length we may safely confine our inquiries to the English yard and the French toise and meter, for during the last two hundred years they have been almost the only standards adopted in scientific operations. The English measures of length have come down from the Saxons, but the oldest standards now existing are the Exchequer yards of XLIV PHILOSOPHICAL SOCIETY OP WASHINGTON. Henry VII (1490) 1 and Elizabeth (1588).2 These are both brass end measures, the former being an octagonal rod about half an inch in diameter, very coarsely made, and as rudely divided into inches on the right hand end and into sixteenths of a yard on the left hand end ; the latter a square rod with sides about half an inch wide, also divided into sixteenths of a yard and provided with a brass bed having end pieces between which the yard fits. One end of the bed is divided into inches and half inches. Francis Baily, who saw this Elizabethan standard in 1836, speaks of it as " this curious instru- ment, of which it is impossible, at the present day, to speak too much in derision or contempt. A common kitchen poker, filed at the ends in the rudest manner by the most bungling workman, would make as good a standard. It has been broken asunder ; and the two pieces have been dove-tailed together: but so badly that the joint is nearly as loose as that of a pair of tongs. The date of this fracture I could not ascertain, it having occurred beyond the memory or knowledge of any of the officers at the Exchequer. And yet, till within the last 10 years, to the disgrace of this country, copies of this measure have been circulated all over Europe and America, with a parch- ment document accompanying them (charged with a stamp that costs £3. 10s. exclusive of official fees) certifying that they are true copies of the English standard."3 In the year 1742 certain members of the Royal Society of Lon- don, and of the Royal Academy of Sciences of Paris, proposed that, in order to facilitate a comparison of the scientific operations car- ried on in the two countries, accurate standards of the measures and weights of both should be prepared and preserved in the ar- chives of each of these societies. This proposition having been approved, Mr. George Graham at the instance of the Royal Society had two substantial brass rods made, upon which he laid off, with the greatest care, the length of three English feet from the stan- dard yard kept at the Tower of London. These two rods, together with a set of troy weights, were then sent over to the Paris Acad- emy, which body, in like manner, had the measure of a French half toise set off upon the rods, and keeping one, as previously agreed, returned the other, together with a standard weight of two marcs, to the Royal Society. In 1835, Baily declared this copy of the half 1 43, p. 34, and 44, pp. 51-2. (See Bibliography on page lxxix.) 2 43, p. 25. 3 34, p. 146. ANNUAL ADDRESS OF THE PRESIDENT. XLV toise to be of little value because the original toise-etalon was of iron, and the standard temperature in France differed from that in England.1 In his opinion the French should have sent over an iron half toise in exchange for the English brass yard ; but this criticism loses much of its force when it is remembered that in 1742 neither England nor France had fixed upon a temperature at which their standards were to be regarded as of the true length. On the return of the rod from Paris Mr. Graham caused Jonathan Sisson to divide the English yard and the French half toise each into three equal parts, after which the rod was deposited in the archives of the Royal Society, where it still remains.2 Objection having been made that the original and legal standard yard of England was not the one at the Tower, but the Elizabethian standard at the Ex- chequer, the Royal Society requested Mr. Graham to compare his newly-made scale with the latter standard, and on Friday, April 22, 1743, he did so in the presence of a committee of seven mem- bers of the Royal Society. In the following week the same gentle- men compared the Royal Society's scale with the standards at Guildhall and the Tower, and also with the standard of the Clock- makers' Company. These comparisons having shown that the copy of the Tower yard upon the Royal Society's scale was about 0'0075 of an inch longer than the standard at the Exchequer, Mr. Graham inscribed upon the Royal Society's scale a copy of the latter stand- ard also, marking it with the letters Exch., to distinguish it from the former, which was marked E. (English), and from the half toise which was marked F. (French).3 In the year 1758 the House of Commons appointed a committee to inquire into the original standards of weights and measures of England; and, under instructions from that committee, the cele- brated instrument maker, John Bird, prepared two brass rods, respecting which the committee speak as follows in their report : "And having those rods, together with that of the Royal Society laid in the same place, at the receipt of the Exchequer, all night with the standards of length kept there, to prevent the variation which the difference of air might make upon them, they the next morning compared them all, and, by the means of beam compasses brought by Mr. Bird, found them to agree as near as it was possible." * One of these rods was arranged as a matrix for testing end meas- ^4, p. 37. 2 6, pp. 185-8. 3 7, pp. 541-556. *11, p. 434. XLVI PHILOSOPHICAL SOCIETY OF WASHINGTON. ures, and the other was a line measure which the committee recom- mended should be made the legal standard of Eifgland, and which has since been known as Bird's standard of 1758. Respecting the statement that after lying together all night the rods were all found to agree as near as it was possible, Baily says : " This is somewhat remarkable, and requires further explanation, which unfortunately cannot now be accurately obtained. For it is notorious that the meas- ure of the yard of the Royal Society's scale differs very considerably from the standard yard at the Exchequer : * * * Owing to this singular confusion of the lengths of the measures, which does not appear to have been unraveled by any subsequent Committee, it has happened that the Imperial standard yard * * * has been assumed nearly 1 — 140 of an inch longer than the ancient measure of the kingdom." 1 There is little difficulty in surmising what Bird did. The Exchequer standard consisted of a rod and its matrix. The Royal Society's committee assumed the rod to be the true standard of 36 inches, and upon that assumption Graham's measurements gave for the length of the matrix 36 -0102 inches, and for the length of the Royal Society's yard 36 -0075 inches. The Parliamentary committee of 1758 probably assumed the standard to consist of the rod and matrix together, which seems the better view ; and by laying the rod in its matrix and measuring to the joint between them, Bird would have got a length of about 36*0051 inches. The mean between that and 36*0075 would be 36"0063, which differs very little from the length of Bird's standard result- ing from Sir George Shuckburgh's measurements. Thus the com- mittee's statement is justified, and there has been no falsification of the ancient standards. On December 1, 1758, Parliament created another committee on weights and measures which in April, 1759, repeated the recommen- dation that Bird's standard of 1758 should be legalized, and further recommended that a copy of it should be made and deposited in some public office, to be used only on special occasions.2 The copy was made by Bird in 1760, but owing to circumstances entirely un- connected with the subject, no legislation followed for sixty-four years. The Royal Commission appointed during the reign of George III, to consider the subject of weights and measures, made its first report »34, p. 43. 2 12, p. 463. ANNUAL ADDRESS OF THE PRESIDENT. XLVII on June 24, 1819, and therein recommended the adoption of the standard of length which had been used by General Roy in measur- ing the base on Hounslow Heath ; l but in a second report made July 13, 1820, they wrote, " We * * * have examined, since our last report, the relation of the best authenticated standards of length at present in existence, to the instruments employed for measuring the base on Hounslow Heath, and in the late trigonome- trical operations—But we have very unexpectedly discovered, that an error has been committed in the construction of some of these instruments :2 We are therefore obliged to recur to the originals which they were intended to represent, and we have found reason to prefer the Parliamentary standard executed by Bird in 1760, which we had not before received, both as being laid down in the most ac- curate manner, and as the best agreeing with the most extensive comparisons, which have been hitherto executed by various observers, and circulated through Europe ; and in particular with the scale employed by the late Sir George Shuckburgh." 3 Accordingly, when in 1824 Parliament at length took action, Bird's standard of 1760 was adopted instead of that of 1758. The former being a copy of a copy, its selection as a national standard of length seems so singular that the circumstances which brought about that result should scarcely be passed over in silence. Bird had a very accurate brass scale 90 inches long, which he used in all his dividing operations, whether upon circles or straight lines, and which Dr. Maskelyne said was 0*001 of an inch shorter on three feet than Graham's Royal Society yard E.* In the year 1792, or 1793, the celebrated Edward Troughton made for himself a five foot scale, which conformed to Bird's, and which he afterwards used in laying down the divisions of the various instruments that passed through his hands. This was the original of all the standard scales he ever made, and at the beginning of the present century he be- lieved these copies, which were made by the aid of micrometer microscopes, to be so exact that no variations could possibly be de- tected in them, either from the original or from each other. Among the earliest of the scales so made by Troughton was the one used by Sir George Shuckburgh in 1796-8 in his important scientific opera- tions for the improvement of the standards. Subsequently, the length of the meter was determined by comparison with this scale ^3, p. 4. 2 27, p. 92. 3 24, p. 3; also, 25 and 26. *13, p. 326. XLVIII PHILOSOPHICAL SOCIETY OP WASHINGTON. and with the supposed fac-simile of it made by Troughton for Pro- fessor Pictet, of Geneva, and thus it happened 'that on the conti- nent of Europe all measures were converted into English units by a reference to Sir George Shuckburgh's scale. The Royal Commis- sion of 1819, believed Bird's standard of 1760 to be identical with Shuckburgh's scale, and they legalized it rather than the standard of 1758, in order to avoid disturbing the value of the English yard which was then generally accepted for scientific purposes. There are yet four other scales of importance in the history of English standards—namely, the brass five-foot scale made for Sir George Shuckburgh by Troughton in 1796 ; two iron standard yards, marked 1A and 2A, made for the English Ordnance Survey department by Messrs. Troughton and Simms in 1826-'7, and the Royal Society's standard yard constructed by Mr. George Dollond, under the direction of Captain Henry Kater, in 1831. Bearing in mind the preceding history, the genesis of the present English standard yard may be thus summarized : In 1742 Graham transferred to a bar made for the Royal Society a length which he intended should be that of the Tower yard, but which was really inter- mediate between the Exchequer standard yard of Elizabeth and its matrix. That length he marked with the letter E, and, although destitute of legal authority, it was immediately accepted as the scientific standard and was copied by the famous instrument makers of the time with all the accuracy then attainable. Thus it is in fact the prototype to which all the accurate scales made in Eng- land between 1742 and 1850 can be traced. Bird's standard of 1758 was compared with the Exchequer standard and with the Royal Society's yard E, and was of a length between the two. Bird's standard of 1760, legalized as the Imperial standard in June, 1824, was copied from his standard of 1758. After becoming the Im- perial standard, Bird's standard of 1760 was compared with Sir George Shuckburgh's scale by Captain Kater in 1830 and by Mr. Francis Baily in 1834; with the Ordnance yards 1A and 2A in 1834 by Lieutenant Murphy, R. E., Lieutenant Johnson, R. 1ST., and Messrs. F. Baily and Donkin ; and with Kater's Royal Society yard by Captain Kater in 1831. On October 16th, 1834, the Im- perial standard (Bird's standard of 1760) was destroyed by the burning of the Houses of Parliament, in which it was lodged, and very soon thereafter the Lords of the Treasury took measures to ANNUAL ADDRESS OF THE PRESIDENT. XLIX recover its length. Preliminary inquiries were begun on May 11, 1838, and on June 20, 1843, they resulted in the appointment of a Commission to superintend the construction of new Parliamentary standards of length and weight, among whose members the Astron- omer Royal (now Sir George B. Airy), Messrs. F. Baily, R. Sheep- shanks, and Prof. W. H. Miller, were prominent. The laborious investigations and experiments carried out by that Commission can- not be described here, but it will suffice to say that for determining the true length of the new standard Mr. Sheepshanks employed a provisional yard, marked upon a new brass bar designated " Brass 2," which he compared as accurately as possible with Sir George Shuckburgh's scale, the two Ordnance yards, and Kater's Royal Society yard. The results in terms of the lost Imperial standard were as follows : Brass bar 2 = 36-000084 from comparison with Shuckburgh's scale, 0-36 in. 36-000280 " " " " 10-46 in. 36-000303 from comparison with the Ordnance yard, 1A. 36-000275 " " » " " 2A. 36-000229 from Capt. Kater's Royal Society yard. Mean = 36-000234 Respecting this mean Mr. Sheepshanks wrote: "This should be pretty near the truth ; but I prefer 36"0002o, if in such a matter such a difference be worth notice. I propose, therefore, in con- structing the new standard to assume that — Brass bar 2 = 36-00025 inches of lost Imperial standard at 62° Fab.." And upon that basis the standard now in use was constructed.1 Turning now to the French standards of length, it is known that the ancient toise de macons of Paris was probably the toise of Charlemagne (A. D. 742 to 814), or at least of some Emperor Charles, and that its etalon was situated in the court yard of the old Chatelet, on the outside of one of the pillars of the building. It still existed in 1714, but entirely falsified by the bending of the upper part of the pillar. In 1668 the ancient toise of the masons was reformed by shortening it five lines ; but whether this reforma- tion was an arbitrary change, or merely a change to remedy the HI, p. 664. L PHILOSOPHICAL SOCIETY OF WASHINGTON. effects of long use and restore the etalon to conformity with some more carefully preserved standard, is not quite clear.1 These old etalons were iron bars having their two ends turned up at right angles so as to form talons, and the standardizing of end measures was effected by fitting them between the talons. Being placed on the outside of some public building, they were exposed to wear from constant use, to rust, and even to intentional injury by malicious persons. Under such conditions every etalon would, sooner or later, become too long and require shortening. Respecting the ancient toise of the masons there are two contra- dictory stories. On December 1, 1714, La Hire showed to the French Academy what he characterized as " a very ancient instru- ment of mathematics, which has been made by one of our most ac- complished workmen with very great care, where the foot is marked, and which has served to re-establish the toise of the Chatelet, as I have been informed by our old mathematicians." 2 Forty-four years later, on July 29, 1758, La Condamine stated to the Academy that " We know only by tradition that to adjust the length of the new standard, the width of the arcade or interior gate of the grand pa- vilion, which served as an entrance to the old Louvre, on the side of the rue Fromenteau was used. This opening, according to the plan, should have been twelve feet wide. Half of it was taken to fix the length of the new toise, which thus became five lines shorter than the old one." 3 Of these two contradictory statements that of La Hire seems altogether most trustworthy, and the ordinary rules of evidence indicate that it should be accepted to the exclusion of the other. In 1668 the etalon of the new toise, since known as the toise-etalon du Chatelet, was fixed against the wall at the foot of the staircase of the grand Chatelet de Paris—by whom or at what season of the year is not known. Strange as it now seems, this standard—very roughly made, exposed in a public place for use or abuse by every- body, liable to rust, and certain to be falsified by constant wear — was actually used for adjusting the toise of Picard, that of Cassini, the toise of Peru and of the North, that of La Caille, that of Mairan —in short, all the toises employed by the French in their geodetic operations during the seventeenth and eighteenth centuries. The lack of any other recognized standard made the use of this one im- 1 1, p. 536 and 2, p. 395. 2 2, p. 395. 3 14, p. 484. ANNUAL ADDRESS OF THE PRESIDENT. LI perative, but the French academicians were well aware of its defects and took precautions to guard against them. The first toise copied from the etalon of the Chatelet for scientific purposes was that used by Picard in his measurement of a degree of the meridian between Paris and Amiens. 1 It was made about the year 1668, and would doubtless have become the scientific standard of France had it not unfortunately disappeared before the degree measurements of the eighteenth century were begun. The second toise copied from the etalon of the Chatelet for scientific purposes was that used by Messrs. Godin, Bouguer, and La Condamine for meas- uring the base of their arc of the meridian in Peru. This toise, since known as the toise du Perou, was made by the artist Langlois under the immediate direction of Godin in 1735, and is still pre- served at the Paris Observatory.2 It is a rectangular bar of polished wrought iron, having a breadth of 1*58 English inches and a thick- ness of 0"30 of an inch. All the other toises used by the Academy in the eighteenth century were compared with it, and, ultimately, it was made the legal standard of France by an order of Louis XV, dated May 16, 1766. As the toise of Peru is the oldest authentic copy of the toise of the Chatelet, the effect of this order was simply to perpetuate the earliest known state of that ancient standard. The metric system originated from a motion made by Talleyrand in the National Assembly of France, in 1790, referring the question of the formation of an improved system of weights and measures, based upon a natural constant, to the French Academy of Sciences ; and the preliminary work was entrusted to five of the most eminent members of that Academy—namely, Lagrange, Laplace, Borda, Monge, and Condorcet. On March 19, 1791, these gentlemen, to- gether with Lalande, presented to the Academy a report contain- ing the complete scheme of the metric system. In pursuance of the recommendations in that report, the law of March 26, 1791, was enacted for the construction of the new system, and the Academy of Sciences was charged with the direction of the necessary opera- tions. Those requisite for the construction of a standard of length 1. The determination of the difference of latitude between Dun- kirk and Barcelona. 1 5, Art. 4, p. 15. 2 14, p. 487 and 46, p. C.2. LII PHILOSOPHICAL SOCIETY OF WASHINGTON. 2. The remeasuremeut of the ancient bases which had served for the measurement of a degree at the latitude of Paris, and for mak- ing the map of France. 3. The verification by new observations of the series of triangles employed for measuring the meridian, and the prolongation of them as far as Barcelona. This work was entrusted to Mechain and Delambre, who carried it on during the seven years from 1791 to 1798, notwithstanding many great difficulties and dangers. The unit of length adopted in their operations was the toise of Peru, and from the arc of 9° 40' 45" actually measured, they inferred the length of an arc of the meri- dian extending from the equator to the pole to be 5,130,740 toises. As the meter was to be one ten millionth of that distance, its length was made 0*5130740 of a toise, or, in the language of the committee, 443*296 lines of the toise of Peru at a temperature of 13° Reaumur (16*° C. or 6H° F.).1 Before attempting to estimate how accurately the standards we have been considering were intercompared it will be well to describe briefly the methods by Avhich the comparisons were effected. In 1742 Graham used the only instruments then known for the pur- pose—namely, very exact beam compasses of various kinds, one having parallel jaws for taking the lengths of the standard rods, another with rounded ends for taking the lengths of the hollow beds, and still another having fine points in the usual manner. The jaws, or points, of all these instruments were movable by micro- meter screws having heads divided to show the eight hundredth part of an inch directly, and the tenth of that quantity by estima- tion ; but Mr. Graham did not consider that the measurements could be depended upon to a greater accuracy than one 1600th of an inch.2 Troughton is generally regarded as the author of the application of micrometer microscopes to the comparison of standards of length, but the earliest record of their use for that purpose is by Sir George Shuckburgh in his work for the improvement of the standards of weight and measure in 1796-8.3 Since then their use has been general ; first, because they are more accurate than beam compasses, 1 19, pp. 432, 433 and 642. *'7, pp. 545-6. 3 18, p. 137. ANNUAL ADDRESS OF THE PRESIDENT. LILT and, second, because they avoid the injury to standard scales which necessarily results from placing the points of beam compasses upon their graduations. As the objective of the microscope forms a mag- nified image of the standard, upon which the micrometer wires are set by the aid of the eye piece, it is evident that in order to reduce the effect of imperfections in the micrometer, the objective should have the largest practicable magnifying power. To show the pro- gress in that direction the optical constants of the microscopes, by means of which some of the most important standards have been compared, are given in the accompanying table. 1797 1817 1834 1834 1850 1864 1880 1883 Observer. Sir Geo. Shuckburgh Capt. Henry Kater Francis Baily Lieut. Murphy. E. E. R. Sheepshanks Gen. A. R. Clarke, R. E Prof. W. A. Rogers, 1 in. obj. " " £ in. obj. " " \ in. obj. International Bureau 14 18 27 60 90 o -0. (London, 1835. 4to.) ANNUAL ADDRESS OF THE PRESIDENT. LXII1 passed. Probably the corrections found in the least square adjust- ment of extensive systems of longitude determinations afford the best criterion for estimating the accuracy of first-class modern time observations, and from them it appears that the error of such ob- servations may rise as high as ± 0'05 of a second. During the intervals between successive observations of the heavenly bodies we necessarily depend upon clocks and chronom- eters for our knowledge of the time, and very erroneous ideas are frequently entertained respecting the accuracy of their ruiming. The subject is one upon which it is difficult to obtain exact infor- mation, but there are few time-pieces which will run for a week without varying more than three-quarters of a second from their predicted error. As the number of seconds in a week is 604,800, this amounts to saying that the best time-pieces can be trusted to measure a week within one part in 756,000. Nevertheless, clocks and chronometers are but adjuncts to our chief time-piece, which is the earth itself, and upon the constancy of its rotation depends the preservation of our present unit of time. Early in this century Laplace and Poisson were believed to have proved that the length of the siderial day had not changed by so much as the one hun- dredth part of a second during the last 2,500 years, but later inves- tigations show that they were mistaken, and, so far as we can now see, the friction produced by the tides in the ocean must be steadily reducing the velocity with which the earth rotates about its axis. The change is too slow to become sensible within the lifetime of a human being, but its ultimate consequences will be most momentous. Ages ago it was remarked that all things run in cycles, and there is enough truth in the saying to make it as applicable now as on the day it was uttered. The Babylonian or Chaldean system of weights and measures seems to be the original from which the Egyptian system was derived, and is probably the most ancient of which we have any knowledge. Its unit of length was the cubit, of which there were two varieties, the natural and the royal. The foot was two-thirds of the natural cubit. Kespecting the earliest Chaldean and Egyptian system of weights no very satisfactory information exists, but the best authorities agree that the weight of water con- tained in the measure of a cubic foot constituted the talent, or larger unit of weight, and that the sixtieth or fiftieth parts of the talent constituted, respectively, the Chaldean and Egyptian values of the mina, or lesser unit of commercial weight. Doubtless these weights LXIV PHILOSOPHICAL SOCIETY OF WASHINGTON. varied considerably at different times and places, just as the modern pound has varied, but the relations stated are belteved to have been the original ones. The ancient Chaldeans used not only the decimal system of notation, which is evidently the primitive one, but also a duodecimal system, as shown by the division of the year into twelve months, the equinoctial day and night each into twelve hours, the zodiac into twelve signs, etc., and a sexagesimal system by which the hour was divided into sixty minutes, the signs of the zodiac into thirty parts or degrees, and the circle into 360 degrees, with further sexagesimal subdivisions. The duodecimal and sexagesimal systems- seem to have originated with the Chaldean astronomers, who, for some reason which is not now evident, preferred them to the decimal system, and by the weight of their scientific authority impressed them upon their system of weights and measures. Now observe how closely the scientific thought of to-day repeats the scientific thought of four thousand years ago. These old Chaldeans took from the human body what they regarded as a suitable unit of length, and for their unit of mass they adopted a cube of water bearing simple relations to their unit of length. Four thousand years later, when these simple relations had been forgotten and impaired, some of the most eminent scientists of the last century again undertook the task of constructing a system of weights and measures. With them the duodecimal and sexagesimal systems were out of favor, while the decimal system was highly fashionable, and for that reason they subdivided their units decimally instead of duodecimally, sexagesi- mal^, or by powers of two ; but they reverted to the old Chaldean device for obtaining simple relations between their units of length and mass, and to that fact alone the French metric system owes its sur- vival. Every one now knows that the meter is not the ten millionth part of a quadrant of the earth's meridian, and in mathematical physics, where the numbers are all so complicated that they can only be dealt Avith by the aid of logarithms, and the constant -, an utterly irrational quantity, crops up in almost every integral, mere decimal subdivision of the units counts for very little. But in some departments of science, as, for example, chemistry, a simple relation between the unit of length (which determines volume), the unit of mass, and the unit of specific gravity, is of prime impor- tance ; and wherever that is the case the metric system will be used. To engineers such relations are of small moment, and consequently among English-speaking engineers the metric system is making no ANNUAL ADDRESS OF THE PRESIDENT. LXV progress, while, on the other hand, the chemists have eagerly- adopted it. As the English yard and pound are the direct descend- ants of the Chaldean-Babylonian natural cubit and mina, it is not surprising that the yard should be only 0*48 of an inch shorter than the double cubit, and the avoirdupois pound only 665 grains lighter than the Babylonian commercial mina ; but, considering the origin of the metric system, it is rather curious that the meter is only 1*97 inches shorter than the Chaldean double royal cubit, and the kilogram only 102 grains heavier than the Babylonian royal mina. Thus, without much exaggeration, we may regard the pres- ent English and French fundamental units of length and mass as representing respectively the commercial and royal units of length and mass of the Chaldeans of four thousands years ago. Science tells us that the energy of the solar system is being slowly dissipated in the form of radiant heat ; that ultimately the sun will grow dim ; life will die out on the planets ; one by one they will tumble into the expiring sun ; and at last darkness and the bitter cold of the absolute zero will reign over all. In that far-distant future imagine some wandering human spirit to have penetrated to a part of space immeasurably beyond the range of our most pow- erful telescopes, and there, upon an orb where the mechanical arts flourish as they do here, let him be asked to reproduce the standards of length, mass, and time with which we are now familiar. In the presence of such a demand the science of the seventeenth and eight- eenth centuries would be powerless. The spin of the earth which measures our days and nights would be irretrievably gone ; our yards, our meters, our pounds, our kilograms would have tumbled with the earth into the ruins of the sun, and become part of the debris of the solar system. Could they be recovered from the dead past and live again ? The science of all previous ages mournfully answers, No ; but with the science of the nineteenth century it is otherwise. The spectroscope has taught us that throughout the visible universe the constitution of matter is the same. Everywhere the rythmic motions of the atoms are absolutely identical, and to them, and the light which they emit, our wandering spirit would turn for the recovery of the long-lost standards. By means of a diffraction grating and an accurate goniometer he could recover the yard from the wave length of sodium light with an error not exceeding one or two thou- sandths of an inch. Water is everywhere, and with his newly re- LXVI PHILOSOPHICAL SOCIETY OF WASHINGTON. covered yard he could measure a cubic foot of it, and thus recover the standard of mass which we call a pound. Xhe recovery of our standard of time would be more difficult ; but even that could be accomplished with an error not exceeding half a minute in a day. One way would be to perform Michelson's modification of Foucault's experiment for determining the velocity of light. Another way would be to make a Siemen's mercury unit of electrical resistance, and then, either by the British Association method or by Lord Rayleigh's modification of Lorenz's method, find the velocity which measures its resistance in absolute units. Still another way would he to find the ratio of the electro-static and electro-magnetic units of electricity. Thus all the units now used in transacting the world's business could be made to reappear, if not with scientific, at least with commercial accuracy, on the other side of an abyss of time and space before which the human mind shrinks back in dismay. The science of the eighteenth century sought to render itself immortal by basing its standard units upon the solid earth, but the science of the nineteenth century soars far beyond the solar system and con- nects its units with the ultimate atoms which constitute the universe itself. ANNUAL ADDRESS OP THE PRESIDENT. LXVII NOTE A. The appended table exhibits the principal comparisons hitherto made of the more important early English standards of length. The significations of the reference numbers, and the authorities for the descriptions of the standards, are as follows: No. 1. Standard yard of Henry VII (1490); an end measure formed of an octagonal brass rod half an inch in diameter. No. 2. Standard yard of Queen Elizabeth (1588) ; an end meas- ure formed of a brass rod six-tenths of an inch square. No. 3. Matrix to Queen Elizabeth's standard yard (1588) ; of brass, li inches wide, 1 inch thick, and 49 inches long. No. 4. StandUrd ell of Queen Elizabeth (1588); an end meas- ure of brass, six-tenths of an inch square. No. 5. Standard yard of the Clock-makers' Company (1671) ; a matrix, formed by two pins in an octagonal brass rod half an inch in diameter. No. 6. Standard yard at the Tower ; a line measure, marked on a brass bar seven-tenths of an inch square and 41 inches long. No. 7. Graham's Royal Society scale (1742) ; a line measure, on a brass bar half an inch wide, one-quarter of an inch thick, and 42 inches long. Line marked E. Mem. Roy. Ast. Soc, Vol. 9, p. 82. No. 8. Ditto. Line marked Exch. * No. 9. Ditto. Paris half toise ; marked F. Numbers 1 to 9 are described in the Philosophical Transactions, 1743, pp. 547-550. No. 10. Bird's standard yard of 1758; a line measure, on a brass bar l'Ol inches square, and 39'06 inches long. Mem. Roy. Ast. Soc, Vol. 9, p. 80. No. 11. Bird's standard yard of 1760; a line measure, on a brass bar 1*05 inches square, and 39"73 inches long. Mem. Roy. Ast. Soc, Vol. 9, pp. 80-82. No. 12. General Roy's scale; a line measure, upon a brass bar 0'55 of an inch broad, about 0"22 of an inch thick, and 42 -8 inches LXVIII PHILOSOPHICAL SOCIETY OF WASHINGTON. long ; divided by Bird. Phil. Trans., 1785, p. 401, and Measure- ment of Lough Foyle Base, p. 73. No. 13. Ramsden's bar, used in the trigonometrical survey of Great Britain. Phil. Trans., 1821, p. 91; and Measurement of Lough Foyle Base, pp. 73-4. No. 14. Sir Geo. Shuckburgh's scale (1796) ; a line measure, upon a brass bar 1*4 inches broad, 0*42 of an inch thick, and 67*7 inches long. Space compared, in to 36ia . Phil. Trans., 1798, p. 133, and Mem. Roy. Ast. Soc, Vol. 9, pp. 84-5. No. 15. Ditto. Space compared, 10in to 46in . No. 16. Ordnance yard 1A (1827) ; a line measure, upon an iron bar 1*45 inches broad, 2*5 inches deep, and rather more than 3 feet long. Measurement of Lough Foyle Base, pp. 71, 82 and [28]. No. 17. Ordnance yard 2A (1827). Similar to 1A. Same authorities. No. 18. Captain Kater's Royal Society yard (1831); a line measure, upon a brass plate 0"07 of an inch thick. Phil. Trans., 1831, p. 345. No. 19. The Royal Astronomical Society's standard scale (1834) ; a line measure, upon a brass tube 1*12 inches exterior diameter, 0"74 of an inch interior diameter, and 63 inches long. The central yard was the space compared. Mem. Roy. Ast. Soc, Vol. 9, p. 69. No. 20. "Col. Lambton's standard;" a line measure, upon a brass plate 0*92 of an inch broad, 0"21 of an inch thick, and 66 } inches long ; strengthened by an edge bar of nearly the same breadth, but only 0'08 of an inch thick. Phil. Trans., 1821, p. 88, and Mem. Roy. Ast. Soc, Vol. 9, pp. 82-3. The authorities for the comparisons given in the various columns of the table are as follows: Column A.—Comparisons by Mr. George Graham. Phil. Trans., 1743, pp. 187, and 547-550. Column B.—Comparisons by Sir Geo. Shuckburgh. Phil. Trans., 1798, pp. 167-181. Column C.—Comparisons by Capt. Kater. Phil. Trans., 1818, p. 55, and 1821, p. 91. ANNUAL ADDRESS OF THE PRESIDENT. LXIX Column D.—Comparisons by Capt. Kater. Phil. Trans., 1830, p. 377, and 1831, p. 347. Column E.—Comparisons by Francis Baily, Esq. Mem. Roy. Ast. Soc, Vol. 9, p. 145. Column F.—Comparisons by Francis Baily, Esq. Mem. Roy. Ast. Soc, Vol. 9, p. 120. Column G.—Values adopted by R. Sheepshanks, Esq. Phil. Trans., 1857, p. 661. The values used by Mr. Sheepshanks in 1848 to determine the length of the present Imperial standard yard were Nos. 14 D, 15 F, 16 and 17 G, and 18 D. It will be observed that several different units are employed in the various columns of the table, and care must be taken to allow for that circumstance when comparing numbers not situated in the same column. Comparisons of the Fundamental English Standards of Length. Ref. No. LXX PHILOSOPHICAL SOCIETY OF WASHINGTON. NOTE B. By direction of the Parliamentary Committee of 1758, and in the presence both of that body and of Mr. Farley, deputy chamber- lain, Messrs. Harris and Gregory of the Loudon Mint compared the several standard troy weights of the Exchequer, with the fol- lowing results : 4-oz. weight= All smaller weights — i grain. 8-oz. " = " +i " 16-oz. " = " +i " 32-oz. " = " +2 grains. 64-oz. " = " +3 " 128-oz. " = " +14 " 256-oz. " = " —21 " The weighings which yielded these results were made at the Lon- don Mint; the instruments employed being "a very curious and. exact pair of scales, belonging to Mr. Harris, and the scales used at the Mint for the weighing of gold." After recording the results in their report,1 the Committee continued as follows : " Therefore beginning the difference from the sixteen-ounce weight, and carrying it on to the greatest troy weight in the Exchequer, the total differ- ence will be eight grains and one-half." " The fourth part of which is two grains upon sixteen ounces, which is a. grain and a half upon the twelve ounces or pound troy." "Then the eight and four ounces troy of the Exchequer were compared with the following weights : " " First, with the pound troy used at the Mint in weighing of gold, which was heavier than that at the Exchequer one grain." " Secondly, with the eight and four ounces at the Mint of the 6th of Queen Anne, 1707, which was heavier than that at the Exchequer half a grain." " The eight and four ounces of Queen Elizabeth 1588 at the Mint, was heavier than that at the Exchequer three quarters of a grain ; another of the same year of Queen Elizabeth at the Mint, stampt with a tower, a thistle and crown, and EL and crown, was heavier than that at the Ex- chequer one grain." »11, p. 437. ANNUAL ADDRESS OF THE PRESIDENT. LXXI " Mr. Freeman produced a four and eight ounce of the 6th of Queen Anne 1707 by which he makes weights for sale, which was heavier than the same weights at the Exchequer one grain and three quarters : There- fore, upon an average of all these weights, the pound troy should be one grain heavier than the weights at the Exchequer, and that added to the grain and a half, which, upon the former experiments, the weights at the Exchequer are too light a medium taken from thence makes the proper increase of the Exchequer pound troy to be one grain and one quarter." "And it is to be observed, that the pound troy weight at the Mint, which is now used for gold, and the eight and four ounces at the Mint, marked with a tower, and in the time of Queen Elizabeth, are both one grain heavier than the eight and four ounces of the Exchequer." " And considering that the Exchequer weights have been used ever since the 30th of Queen Elizabeth, 1588, one hundred and seventy years to size other weights by, it is highly probable that the difference may have been occasioned by the frequent use of the standard." "Your Committee endeavored to compare the troy weights with the original standard at Goldsmith's Hall, from whence it is said, in the afore- said verdict of the 29th and 30th of Elizabeth, that the weights now at the Exchequer were made, and for that purpose sent to Goldsmith's Hall for the said weights ; but were informed that no such were to be found there, the Goldsmith's having no weights older than those at the Exchequer ; " The Committee's statement respecting the way in which the cor- rection of 1J grains was deduced from the weighings of the Ex- chequer weights is very obscure, and the result is not justified by generally accepted principles. If we put x for the sum of all the weights smaller than 4 ounces, then the results of the weighings made by the Committee may be written in the form : 4-oz. divided = 1 x 4-oz. weight = 1 x — \ grain. 8-oz. weight = 2 x -{- I grain. 16-oz. weight = 4 x + 1 grain. 32-oz. weight = 8 x + 2i grains. (1) 64-oz. weight = 16 x + 5i grains. 128-oz. weight = 32 x + 22 grains. 256-oz. weight = 64 x -\- 9 grains. Before proceeding further we must decide in what sense these weights are to be regarded as standards, and perhaps the most natural course will be to regard the entire set as a standard of 512 46 LXXII PHILOSOPHICAL SOCIETY OF WASHINGTON. troy ounces. la that case the summation of the several columns gives 512 ounces = 128 x + 39 grains whence x = 4 ounces — 0*3047 grain (2) and by substituting that value in the equations (1) we obtain the corrections to the several weights given in the second column of Table I. Table I. — Corrections to the Exchequer Standard Troy Weights of 1588, derived from the Weighings made by Messrs. Harris and Chiskolm. Denomination of Weight. ANNUAL ADDRESS OF THE PRESIDENT. LXXIII and in adopting one and one-quarter grains the Committee seem to have augmented the weight of the troy pound by about one-quarter of a grain. The corrections which result to the Exchequer troy weights upon the Committee's assumption that the sum of the eight and four ounce weights was one^ and one-quarter grains too light are given in the third column of Table I; while the fourth column contains the corrections found by Mr. Chisholm in 1873,1 and the fifth column shows the loss of weight which occurred between 1758 and 1873. In view of the fact that these weights were constantly used for comparing local standards during a period of no less than 225 years, from 1588 to 1825, their excellent preservation is very remarkable. In the report of the Committee of 1758 there is another set of comparisons of the Exchequer troy weights;2 said comparisons having been made on April 14, 1758, in accordance with the di- rections of the Committee, by Mr. Freeman and Mr. Keed, expert scale makers, in the presence of Mr. Farley, deputy chamberlain. They are as follows : i-oz. hollow = i-oz. solid -f- h grain. i-oz. we £-oz. 1-oz. 2-oz. 4-oz. 8-oz. 16-oz. 32-oz. 64-oz. 128-oz. 256-oz. ght = All smaller weights — £ grain. « LXXIV PHILOSOPHICAL SOCIETY OF WASHINGTON. i-oz. weight = 2x. £-oz. " = Ax. 1-oz. " = 8x. 2-oz. " = 16x. 4-oz. " = 32a; + J grain. (3) .8-oz. " = 64a; + 1 " 16-oz. " = 128a; + 2 grains. 32-oz. " = 256.r+2 " 64-oz. " = 512a; + 6 " 128-oz. " = 1024a; +27 " 256-oz. " = 2048a; + 15 " Summing the various columns 512 ounces = 4096a; -j- 54 grains whence x = i ounce — 001318 grains, (4) and by substituting that value in the equations (3) we obtain the corrections given for the several weights in the second column of Table II. The third column contains the corrections which result upon the Committee's assumption that the sum of the eight and four ounce weights was one and one-quarter grains too light ; and the fourth and fifth colums contain corrections given by Mr. Chisholm in his seventh annual report.1 Mr. Chisholm does not explain how he obtained the corrections quoted in the fourth column of the table, but their close agreement with those in the third column renders it almost certain that they were computed from the comparisons made by Messrs. Freeman and Reed. As the Committee of 1758 used Mr. Harris' weighings to the exclusion of those by Messrs. Freeman and Reed, the adoption of the opposite course by Mr. Chisholm is perhaps explained by the circumstance that in his report on the Exchequer standards2 he has quoted the weighings by Messrs. Free- man and Reed and has attributed them to Mr. Harris. In addition to being less exact, the weighings by Mr. Freeman differ from those by Mr. Harris principally in the sign of the cor- rection to the 32-ounce weight ; the former stating that the 32-ounce weight was lighter than the sum of all the smaller weights, and the latter that it was heavier. To ascertain which was right we have H3, p. 21. a 48,p. 11. ANNUAL ADDRESS OF THE PRESIDENT. LXXV only to compare the resulting systems of corrections with those fouud by Mr. Chisholm in 1873. Table I shows that according to Mr. Harris' weighings all the weights have grown lighter during the in- terval from 1758 to 1873, while Table II shows that according to Mr. Freeman's weighings some have grown lighter and others heavier, and that by quantities which cannot be attributed to accidental errors in the weighings. In view of these facts there cannot be a doubt that the Committee of 1758 was right in using only Mr. Harris' weighings, and it seems equally certain that the numbers in Table I should be adopted to the exclusion of those in Table II. Table II. — Corrections to the Exchequer Standard Troy Weights of 1588, derived from the Weighings made by Messrs. Freeman and Chisholm. Denomination of Weight. LXXVI PHILOSOPHICAL SOCIETY OP WASHINGTON. From comparisons of their troy pound with their avoirdupois pound, and with the two-marc weight sent to them by the French Academy in 1742, the Royal Society of London found1— 1. That the English avoirdupois pound weighed 7,004 troy grains; 2. That the French llvre, consisting of two marcs, weighed 7,560 troy grains ; and for three-quarters of a century the latter value was universally accepted. Further, when the metric system came into being, the kilogram was declared to consist of 18,827*15 French grains, of which the livre contained 9216 2 ; or, in other words, the kilogram was declared equal to 2*04288 livres ; whence, with the Royal So- ciety's value of the livre, the English equivalent of the kilogram was computed to be 15,444 troy grains. During some experiments at the London Mint in March, 1820, it was found that the French livre belonging to that institution weighed only 7555 troy grains. This discovery led to an examina- tion of the Royal Society's standards of 1742, which had been care- fully preserved, and it was found that their livre agreed with that at the Mint, but their troy pound was nearly four grains lighter than the Imperial standard of 1758, and their avoirdupois pound weighed only 7000 troy grains instead of 7004. 3 Thus it was rendered almost certain that the accepted English equivalent of the kilogram was about ten grains too large, and to remove all possible doubt, a direct comparison of the English and French standards of weight was effected in 1821*, through the co-operation of the respective governments, and then it was definitively ascertained that the weight of the kilogram is only 15,433 troy grains. The facts respecting the Royal Society's standards of 1742 are as follows : 1. The weighings recorded in the Philosophical Transactions, 1743, pages 553 and 556, give J 6, p. 187. It is usual to designate 1742 as the date of the exchange of standards, but the remark of Cassini de Thury (4, p. 135) shows that the true date must have been prior to April, 1738. In his paper of November, 1742, Graham makes only the indefinite statement that the exchange was " proposed some time since." 2 Base du Systeme Metrique, T. 3, p. 638. 3 See 36, Vol. 1, p. 140, and 28, p. 19. *28, pp. 19-22. ANNUAL ADDRESS OF THE PRESIDENT. LXXVII R. S. troy lb. = Exch. (8 oz. + 4 oz.) — } grain. (5) R. S. troy lb. = Mint (8 oz. + 4 oz.) — 2| grains. (6) whence Exch. (8 oz. + 4 oz.) = Mint (8 oz. + 4 oz.) — If grains. (7) 2. The weighings by Mr. Harris, for the Parliamentary Com- mittee of 1758, give 1 Exch. (8 oz. + 4 oz.) = Mint (8 oz. + 4 oz.) — J grain. (8) whence, by (6), R. S. troy lb. = Exch. (8 oz. + 4 oz.) — If grains. (9) In equations (6) and (8) the weights at the Mint were those of the sixth of Queen Anne, 1707. 3. In the Philosophical Transactions, 1742, page 187, it is stated that the Paris two-marc weight weighs 7560 troy grains. As the true weight of two marcs is 7554 -22 grains, this implies that the Royal Society's troy pound was too light by 5'78 (5760 -f- 7560) = 4*40 grains. In the Philosophical Transactions, 1742, page 187, it is stated that the Royal Society's avoirdupois pound weighed 7004 troy grains, while the comparisons made in 1820 show that its weight was then only 7000 such grains. This implies that the Royal So- ciety's troy pound was too light by 4 00 (5760 -=- 7000) = 3'29 grains. Finally, the comparisons of 1820 showed that the Royal Society's troy pound was " nearly four grains too light." The mean of these three independent results shows that the Royal Society's troy pound was 3'9 grains lighter than the Imperial standard of 1758 ; whence R. S. troy lb. + 3*9 grains = Standard of 1758 (10) but Standard of 1758 = Exch. (8 oz. + 4 oz.) + 11 grains (11) and therefore R. S. troy lb. = Exch. (8 oz. + 4 oz.) — 2f grains. (12) Considering the indefiniteness of the data respecting the weigh- 1 11, p. 437. LXXVIII PHILOSOPHICAL SOCIETY OF WASHINGTON. ings made in 1820, equations (9) and (12) agree fairly well, but equation (5) is very discordant, as are also equations (7) and (8). All the evidence seems to point to an error of about one and one half grains in equation (5) ; and if instead of (5) we write E. S. Troy lb. = Exch. (8 oz. + 4 oz.) — 2 grains (5') (7) will become Exch. (8 oz. + 4 oz.) = Mint (8 oz. + 4 oz.) — f grain (7') and then all the equations will be reasonably accordant. ANNUAL ADDRESS OF THE PRESIDENT. LXXIX LIST OF THE PRINCIPAL AUTHORITIES CONSULTED IN THE PREPARATION OF THE FOREGOING- ADDRESS. Note.—The abbreviation " E. P. P." is used to designate English Par- liamentary Papers. Some of these papers are of folio size and others of oc- tavo size, but in the official sets they are all bound up indiscriminately in volumes of folio size, measuring 13 by 8^ inches. Throughout the preceding pages authorities in this list are usually cited by number and page. For example, "27, p. 91 " would indicate page 91 of Capt. Kater's account of his comparisons of various British standards of linear measure, contained in the Philosophical Transactions for 1821. 1. — Picard; M. l'Abbe. De Mensuris. Divers ouvrages. Mem. de l'Acad. Roy. des Sciences, 1666-1699, Tome 6, pp. 532-549. Paris, 1730. 2. Hire ; M. de la. Comparaison du pied antique Romain a celui du Chatelet de Paris, avec quelques remarques sur d'autres mesures. Mem. de l'Acad. Roy. des Sciences, 1714, pp. 394-400. Paris, 1717. 3. Matjperttjis. La figure de la terre, determined par les observations de MM. de Maupertuis, Clairaut, Camus, le Monnier, * * * Outhier, * * * Celsius, * * * faites par ordre du Roy au cercle polaire. Paris, 1738. 16mo., pp. xxviii + 184. 4. Cassint de Thttrt. Sur la propagation du son. (On p. 135 has statement respecting standards of length exchanged between the French Academy and the English Royal Society.) Mem. de l'Acad. Roy. des Sci- ences, 1738, pp. 128-146. Paris, 1740. 5.—Degre du meridien entre Paris et Amiens, determine par la mesure de M. Picard et par les observations de MM. de Maupertuis, Clairaut, Camus, le Monnier, * * * Paris, 1740, 16mo, pp. lvj -f 116. 6. Graham ; George. An account of the proportions of the English and French measures and weights, from the standards of the same, kept at the Royal Society. Phil. Trans., 1742, pp. [185-188]. 7. Graham ; George. An account of a comparison lately made by some gentlemen of the Royal Society, of the standard of a yard, and the several weights lately made for their use; with the original standards of measures and weights in the Exchequer, and some others kept for public use, at Guild-hall, Founders-hall, the Tower, etc. Phil. Trans., 1743, pp. [541-556]. 8. Cassini de Thxjry. La meridienne de l'observatoire royal de Paris, verifiee dans toute l'etendue du royaume par de nouvelles observations : Paris, 1744. 8vo, pp. 292 -f- ccxxxvj. LXXX PHILOSOPHICAL SOCIETY OP WASHINGTON. 9. — Condamine; M. de la. Nouveau projet d'une mesure invariable, propre a servir do mesure commune a toutes les nations. Mem. de l'Acad. Koy. des. Sciences, 1747, pp. 489-514. Paris, 1752. 10. — Bouguer, Camus, Cassini de Thury & Pingre. Operations faites par ordre de l'Academie pour mesurer l'intervalle entre les centres des Pyramides de Villejuive & de Juvisy, &c. Mem. de l'Acad. Royale des Sciences, 1754, pp. 172-186. Paris, 1759. 11.—1758. Report from the Committee appointed to inquire into the original standards of weights and measures in this Kingdom, and to con- sider the laws relating thereto. (Agreed to by the House June 2, 1758.) Printed on pp. 411-451 of Reports from Committees of the House of Com- mons, which have been printed by order of the House, and are not inserted in the Journals. Reprinted by order of the House. Vol. 2. (June 10, 1737, to May 21, 1765). Folio, 16|" X 10£". pp. 468. 12.—1759. Report from the Committee appointed (upon the first day of Dec, 1758) to inquire into the original standards of weights and measures in this Kingdom, and to consider the laws relating thereto. (Agreed to by the House April 12, 1759.) Printed on pp. 453-463 of Reports from Com- mittees of the House of Commons, which have been printed by order of the House, and are not inserted in the Journals. Reprinted by order of the House. Vol. 2. (June 10, 1737, to May 21, 1765). .Folio, 16f" X 10f'. pp. 468. 13. Maskelyne; Rev. Nevil (Ast. Royal). The length of a degree of latitude in the province of Maryland and Pennsylvania, deduced from the foregoing operations (by Messrs. Chas. Mason and Jeremiah Dixon); by the Astronomer Royal. Phil. Trans., 1768, pp. 323-325. 14.— Condamine ; M. de la. Remarques sur la toise-etalon du Chate- let, ct sur les diverse? toises employees aux mesures des degres terrestres & a celle du pendule a secondes. Mem. de l'Acad. Roy. des Sciences, 1772, 2e partie. pp. 482-501. Paris, 1776. 15. Roy; Maj.-Gen. Wm. An account of a measurement of a base on Hounslow Heath. (Four large folding plates.) Phil. Trans., 1785, pp. 385-480. 16. La Lande ; Jerome le Francais. De la grandeur et de la figure de la terre. Astronomie, Tome 3, pp. 1-47. (3d edition ; Paris, 1792.) 17. Borda, Coulomb, Legendre, Laplace, Prony, et Brisson. Rap- port sur la verification de l'etalon qui doit servir pour la fabrication des poids republicans. Annales de Chiinie, Paris, 1797, Tome 20, pp. 269-273. 18. Shuckburgh Evelyn; Sir Geo. An account of some endeavors to ascertain a standard of weight and measure. Phil. Trans., 1798, pp. 133-182. ANNUAL ADDRESS OP THE PRESIDENT. LXXXI 19. — Van-Swinden, Tralles, Laplace, Legendre, Mechain, De- LAMBRE, Ciscar. Rapport lur 1?, determination de la grandeur de Pare du meridien compris entre les paralleles de Dunkerque et Barcelone, et sur la longueur du metre qu'on en deduit. Base du Systeme Metrique Decimal, Tome 3, pp. 415-433. Paris, 1810. 4to. 20. Kater; Capt. Henry. An account of experiments for determin- ing the length of the pendulum vibrating seconds in the latitude of London. Phil. Trans., 1818, pp. 33-102. 21. Kater; Capt. Henry. On the length of the French metre esti- mated in parts of the English standard. Phil. Trans., 1818, pp. 103-109. 22.—Experiments relating to the pendulum vibrating seconds of time in the latitude of London. 41 pp. (E. P. P.) Accounts and papers. Ses- sion, 27 Jan.-lO June, 1818. Vol. 15. Folio, 13}" X W- This is a ver- batim reprint of Capt. Kater's papers in the Phil. Trans., 1818, pp. 33 to 109. 23. Banks, Clerk, Gilbert, Wollaston, Young, and Kater. First Report of the Commissioners appointed to consider the subject of weights and .measures. (Dated 24 June, 1819) 17 pp. (E. P. P.) Report from Commissioners. Session, 21 Jan.-13 July, 1819. Vol. 11. Folio, 13}" X8J"- 24. Clerk, Gilbert, "Wollaston, Young & Kater. Second Report of the Commissioners appointed hy His Majesty to consider the subject of weights and measures. (Dated July 13, 1820) 40 pp. (E. P. P.) Reports from Commissioners. Session, 21 April to 23 Nov. 1820. Vol. 7. Folio, 131" X 8J". 25. Clerk, Gilbert, Wollaston, Young & Kater. Third Report of the Commissioners appointed by His Majesty to consider the subject of weights and measures. (Dated Mar. 31, 1821) 6 pp. (E. P. P.) Reports from Committees. Session, 23 Jan. to 11 July, 1821. Vol. 4. Folio, 13}" X 8}". 26.—Report from the Select Committee on weights and measures. (Dated May 28, 1821) 7 pp. (E. P. P.) Reports from Committees. Session, 23 Jan. to 11 July, 1821. Vol. 4. Folio, 13}" X 8J". 27. Kater ; Capt. Henry. An account of the comparison of various British standards of linear measure. Phil. Trans., 1821, pp. 75-94. 28.—Report from the Select Committee of the House of Lords * * * (on petition from Glasgow relative to) * * * the bill entitled " An act for ascertaining and establishing uniformity of weights and measures" * * * together with the minutes of evidence taken before said Commit- tee. (Dated 2 Mar., 1824) 35 pp. (E. P. P.) Reports from Committees. Session, 3 Feb. to 25 June, 1824. Vol. 7. Folio, 13" X 8£". 29. Kater; Capt. Henry. An account of the construction and adjust- LXXXII PHILOSOPHICAL SOCIETY OF WASHINGTON. ment of the new standards of weights and measures of the United Kingdom of Great Britain and Ireland. Phil. Trans., 1823, part 2, pp. 1-52. 30. — Kater ; Capt. Henry. On errors in standards of linear measure, arising from the thickness of the bar on which they are traced. Phil. Trans., 1830, pp. 359-381. 31. Kater, Capt. Henry. An account of the construction and verifica- tion of a copy of the imperial standard yard made for the Royal Society. Phil. Trans., 1831, pp. 345-347. 32.—Minutes of evidence taken before the Select Committee on bill to amend and render more effectual two acts of the 5th and 6th years of the reign of his late Majesty King George the 4th, relating to weights and measures. 67 pp. (E. P. P.) Reports from Committees. 1834. Vol. 18, part 1. Folio, 13" X 8\" . 33.—Report from the Select Committee on the weights and measures act ; together with the minutes of evidence. (Dated 17 June, 1835) 60 pp. (E. P. P.) Reports from Committees. Session, 19 Feb.-lO Sep., 1835. Vol. 18. Folio, 13" X 8J". 34. Baily ; Francis. Report on the new Standard Scale of this (the Royal Astronomical) Society. (Gives also a history of English standards of length.) Mem. Roy. Ast. Soc, 1836. Vol. 9, pp. 35-184. 35. Airy, Baily, Bethune, Herschel. Lefevre, Lubbock, Pea- cock, Sheepshanks. Report of the Commissioners appointed to consider the steps to be taken for restoration of the standards of weight and measure. (Dated 21 Dec, 1841) 106 pp.. (E. P. P.) Reports from Commissioners. Session, 3 Feb.-12 Aug., 1842. Vol. 25. Folio. 36. Kelly ; Patrick. The universal cambist : being a full and accu- rate treatise on the exchanges, coins, weights, and measures of all trading nations and their colonies. By P. Kelly, LL.D. 2nd edition. London, 1835. 2 vols., 4to. Vol. 1, pp. xl + 422 ; Vol. 2, pp. xxiv + 380. 37. Yolland ; Capt. Wm. An account of the measurement of Lough Foyle base in Ireland, with its verification and extension by triangulation ; etc., etc. Pub. by order of the Hon. Board of Ordnance. London, 1847. 4to, pp. 154 + [117]. 38. Airy, Rosse, Wrottesley, Lefevre, Lubbock, Peacock, Sheep- shanks, Herschel, Miller. Report of the Commissioners appointed to superintend the construction of new parliamentary standards of length and weight. (Dated March 28, 1854) 23 pp. (E. P. P.) Reports from Com- missioners. Session, 31 Jan.-12 Aug., 1854. Vol.19. Folio, 13" X 8J". 39.—Abstract of " Report of the Commissioners appointed to consider the steps to be taken for restoration of the standards of weight and measure." 16 pp. (E. P. P.) Reports from Commissioners. Session, 12 Dec, 1854- 14 Aug., 1855. Vol. 15. Folio, 13" X 8J". 40. Miller; Prof. W. H. On the construction of the new imperial ANNUAL ADDRESS OF THE PRESIDENT. LXXXIII standard pound, and its copies of platinum ; and on the comparison of the imperial standard pound with the Kilogramme des Archives. Phil. Trans., 1856. pp. 753-946. 41 . — Airy ; Sir Geo. B. Account of the construction of the new national standard of length, and of its principal copies. Phil. Trans., 1857. pp. 621-702. 42. Clarke ; Capt. A. K. Comparisons of the standards of length of England, France, Belgium, Prussia, Russia, India. Australia, made at the Ordnance Survey Office, Southampton. Published by order of the Secretary of State for War. London, 1866. . 4to, pp. 287. 43. Chisholm ; Henry Williams. Seventh annual report of the Warden of the Standards on the proceedings and business of the standard weights and measures department of the Board of Trade. For 1872-3. 8vo, pp. 105. (Contains : Appendix IV.—Account of the standard weights and measures of Queen Elizabeth, pp. 10-26 : Appendix V.—Account of the standard weights and measures of Henry VII. pp. 27-34 : Appendix VI.—New standard weights and measures constructed and legalised from the reign of Queen Elizabeth to George IV. pp. 35-40.) (E. P. P.) Re- ports from Commissioners. Session, 6 Feb.-5 Aug., 1873. Vol. 38. 44. Chisholm ; H. W. On the science of weighing and measuring, and standards of measure and weight. By H. W. Chisholm, warden of the standards. 16mo, pp, xvi -(- 192. London : Macmillan & Co. 1877. 45. Hilgard; Julius E. Report on the comparison of American and British standard yards. Report of the Superintendent of the U. S. Coast Survey, 1877. Appendix No. 12, pp. 148-181. 4to. 46. Wolf ; C. Recherches historiques sur les etalons de poids et mes- ures de l'Observatoire, et les appareils qui ont servi a les construire. An- nates de l'Observatoire do Paris. Memoirs, Tome 17, pp. C.1-C.78. (Pub- lished in 1883.) 47. Wolf ; C. Resultats des comparaisons de la toise du Perou au me- tre international, executees au Bureau international des Poids et Mesures par M. Benoit. Comptes Rendus, 3 Avril, 1888. Tome 106. pp. 977-982. 48.—Copies "of a letter from the Comptroller General of the Exchequer to the Treasury, dated 3 June, 1863, transmitting a report on the Exchequer standards of weight and measure, dated 27 April, 1863, by Mr. Chisholm, chief clerk in the office of the Comptroller General of the Exchequer ; to- gether with a copy of his report: " and, of a memorandum by the Astron- omer Royal, dated 24 April, 1862, containing notes for the Committee on Weights and Measures, 1862. 51 pp. (Contains a complete descriptive list of all the old Exchequer standards ; a discussion on the moneyer's pound ; and a history of English legislation on weights and measures.) (E. V. P.) Trade (Generally). Session, 4 Fel>.-29 July, 1864. Vol. 58. Folio. 49.—Annual reports of the Warden of the Standards on the proceedings and business of the standard weights and measures department of the Board LXXXIV PHILOSOPHICAL SOCIETY OF WASHINGTON. of Trade. 8vo. (Printed as English Parliamentary Papers, and contained in the volumes of "Reports from Commissioners.") No. of Report ANNUAL ADDRESS OF THE PRESIDENT. LXXXV 51. — Airy; Sir Geo. B. Extracts of papers, printed and manuscript, laid before the Commission appointed to consider the steps to be taken for restoration of the standards of weight and measure, and the subjects con- nected therewith. Arranged by G. B. Airy, Esq., Astronomer Royal. Printed by order of the Lords Commissioners of the Treasury. London, 1840. 4to, 155 pp. (Consists of a vast number of brief extracts giving the opinions of many experts upon various points connected with the construc- tion and use of standards of weight and measure, and the advantages and disadvantages of various systems of such standards.) 52. Clarke ; Lt. Col. A. R. Results of the comparisons of the stand- ards of length of England, Austria, Spain, United States, Cape of Good Hope, and of a second Russian Standard, made at the Ordnance Survey Office, Southampton. By Lieutenant-Colonel A. R, Clarke, C. B., R. E., F. R. S., &c., under the direction of Major-General Sir Henry James, R. E., F. R. S., &c, director-general of the Ordnance Survey. "With a preface and notes on the Greek and Egyptian measures of length by Sir Henry James. Phil. Trans., 1873, pp. 445-469. 53. Adams ; John Qtjincy. Report upon weights and measures, by John Quincy Adams, Secretary of State of the United States. Prepared in obedience to the resolution of the Senate of the 3d of March, 1817. Wash- ington : printed by Gales & Seaton. 1821. 8vo, pp. 245. (Contains report of F. R. Hassler on comparisons of English and French measures, pp. 153- 170.) 54. Alexander ; J. H. Report (made to the governor of Maryland) on the standards of weight and measure for the State of Maryland ; and on the construction of the yard-measures. Baltimore, Dec. 13, 1845. 8vo, pp. iv + 213. 55. Hassler; Ferdinand Rodolph. Comparison of weights and meas- ures of length and capacity. Reported to the Senate of the United States by the Treasury Department in 1832, and made by Ferd. Rod. Hassler. 22d Congress, 1st Session, Ho. of Reps., Doc. No. 299. Washington, 1832. 8vo, 122 pp., with 4 folding plates. (Contains a paper by Tralles giving impor- tant details, not published elsewhere, respecting the original iron meters of the Commission des Poids et Mesures of 1799.) 56. Hassler ; F. R. Report from the Secretary of the Treasury, trans- mitting the report of F. R. Hassler, superintendent of the Coast Survey, and of the fabrication of standard weights and measures. 25th Congress, 2d Session, Senate, Doc. No. 79. Washington, 1837. 8vo, 16. pp. (Explains method adopted for determining subdivisions of the troy pound.) 57. Hassler; F. R. Report upon the standards of the liquid capacity measures of the system of uniform standards for the United States ; with description of a new original barometer, and of the balance for adjusting the half bushels by their weight of distilled water. By F. R. Hassler. 27th LXXXVI PHILOSOPHICAL SOCIETY OF WASHINGTON. Congress, 2d Session, Senate, Doc. No. 225. Washington, 1842. 8vo, 26 pp. and 3 folding plates. 58. — Bache, A. D., & McCulloh, R. S. Reports from the Secretary of the Treasury, of scientific investigations in relation to sugar and hydrome- ters, made, under the superintendence of Prof. A. D. Bache, by Prof. R. S. McCulloh. 80th Congress, 1st Session, Senate, Ex. Doc. No. 50. Wash- ington, 1848. 8vo, pp. 653. 59. Bache ; Prof. Alexander D. Report to the Treasury Department on the progress of the work of constructing standards of weights and measures for the custom-houses, and balances for the States, and in supplying stand- ard hydrometers to the custom-houses, from 1 Jan., 1848, to 31 Dec, 1856. 34th Congress, 3d Session, Senate, Ex. Doc. No. 27. Washington, 1857. 8vo, 218 pp. with 6 folding plates. (Contains descriptions of yard dividing engine, and various comparators.) 60. Rogers ; Prof. W. A. On the present state of the question of stand- ards of length. (Contains a bibliography.) Proceed. Amer. Acad, of Arts and Sciences, 1879-80. Vol. 15. pp. 273-312. 61. Rogers; Prof. W. A. On two forms of comparators for measures of length. 8vo, 12 pp. American Quarterly Microscopical Journal, April, 1879. 62. Rogers; Prof. Wm. A. Studies in metrology. 5 Plates. (Con- tains description of the Rogers-Bond universal comparator.) Proceed. Amer. Acad, of Arts and Sciences, 1882-'3. Vol. 18, pp. 287-398. 8vo. 63. Rogers ; Prof. W. A. An examination of the standards of length constructed by the Societe Genevoise. Proceed. Amer. Acad, of Arts and Sciences, 1884-'5. Vol. 20, pp. 379-389. 8vo. 64. Rogers; Prof. W. A. A study of the centimeter marked "A," prepared by the U. S. Bureau of Weights and Measures for the Committee on Micrometry. 8vo, 23 pp. Proc. Amer. Society of Microscopists. Vol. 32, p. 184. 65 —Rogers; Prof. Wm. A. On a practical solution of the perfect screw problem. 8vo, 44 pp. Trans. Amer. Soc. of Mechanical Engineers. Vol.5. 66. Rogers ; Prof. W. A. A critical study of the action of a diamond in ruling lines upon glass. 8vo, 17 pp. Proc. Amer. Society of Microscop- ists. Vol. 32, p. 149. 67.—Travaux et memoires du Bureau International des Poids et Mesures, publies sous l'autorite du Comite International, par le Directeur du Bureau. Paris. 4to. Tome 1, 1881, 391 pp. ; T. 2, 1883, 413 pp. ; T. 3, 1884, 3*48 pp. ; T. 4, 1885, 421 pp. ; T. 5, 1886, 416 pp. BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON. GENERAL MEETINGS. 47 (i) BULLETIN OF THB GENERAL MEETINGS 295th Meeting. January 15, 1887. President Harkness in the Chair. Fifty-one members present. Announcement was made of the election to membership of Messrs. Henry Laurens Whiting and Thomas William Symons. The following report of the Auditing Committee was presented by its chairman, Mr. Woodward, and was accepted : January 15, 1887. The undersigned, a committee appointed at the annual meeting of the Philosophical Society of Washington, December 18, 1886, for the purpose of auditing the accounts of the Treasurer, beg leave to report as follows : We have examined the statement of receipts, including annual dues, sale of Bulletin, and interest on bonds, and find the same to be correct. We have examined the statement of disbursements and compared the same with the vouchers, and find them to agree. We have examined the returned checks and the bank account with Riggs & Co., and find the balance, $485.52, to agree with the statement of the Treasurer's report. We have examined the United States and other bonds belonging to the Society, and find them to be in amount and character as rep- resented in the Treasurer's report, aggregating $3,100. R. S. Woodward, Swan M. Burnett, J. H. Kidder, Committee. (3) 4 PHILOSOPHICAL SOCIETY OP WASHINGTON. Mr. G. K. Gilbert presented a communication entitled GRAPHIC METHODS IN RESEARCH. [Abstract.] An algebraic equation between two variables is the equivalent of a plane curve, or, more strictly, of a line lying in a plane. An equation containing three variables is the equivalent of a surface. If in such an equation one of the variables be assumed equal to 1, 2, 3, etc., successively, there result a series of equations involving the other two variables. Each of these equations may be represented by a line in a plane, and the system of lines thus produced is the representative of the original equation between three variables. The single curve may be called a nomogram, the system of curves an isogram. In the simplest use of the graphic method in research the simul- taneous quantitative observations of two phenomena are represented on cross-section paper by a dot, a series of observations are repre- sented by a system of dots, and a line is drawn through or among these dots. This line expresses the law of the relation between the two phenomena and is a nomogram. When simultaneous observations are made of three phenomena, two of the observations are expressed by a dot on section paper and the third by a number attached to the dot. All the observations having been represented by such numbered dots, a system of lines is drawn over the area occupied by the dots, each line representing an integral value of one of the variable phenomena, and being drawn so as to pass through the dots marked with the correspond- ing number. An isogram is thus produced without recourse to the algebraic equation. In the compound nomogram, two or more curves are drawn on the same sheet, and with one system of ordinates in common. Each of these curves represents an equation with two variables, one vari- able being common to all the equations. By this means two or more variable phenomena are compared with each other through the mediation of another phenomenon with which they are related. In the compound isogram two or more isograms are drawn on the same sheet. Each isogram is the equivalent of an equation between three variables, two variables being common to all the isograms, GENERAL MEETINGS. 5 and one peculiar to each. By this means, variable phenomena are compared with each other with reference to two other phenomena. There are also phases of the graphic method in which lines are not drawn, the arrangement of the platted dots being such that they cannot be replaced by lines, but nevertheless lead to legitimate in- ferences. The function of the graphic method in research is the classifica- tion of observations and their generalization, or the discovery of their laws of relation. The same function is performed by math- ematical analysis, both processes being restricted to the discussion of quantitative observations. As compared to the mathematical method, the graphic is more rapid and less precise. In matters difficult of comprehension it aids the imagination by introducing a sensory impression, and in this manner it suggests inferences and hypotheses which might readily be overlooked if mathematical methods were employed alone. Mr. H. A. Hazen remarked upon the importance of this method in meteorology. He suggested some precautions to be taken in at- tempting to trace a connection by maximum or mininum epochs between elements which are not clearly related or caused by the same force. Mr. Marcus Baker thought that the graphic method had its chief use in rough approximations, and drew attention to the great strides which had been made in geometry by the introduction of analytical methods, supplementing and in part supplanting graphic methods. Mr. Paul remarked that the graphic method might be useful in a preliminary determination of the most promising of several meth- ods of possible analysis. Mr. C. D. Walcott read a paper entitled THE GEOLOGIC AGE OF THE LOWEST FORMATION OF EMMONS' TACONIC SYSTEM, illustrated by maps, drawings, etc. [This paper, in abstract, appeared in the American Journal of Science, 3d series, 8°, New Haven, 1887, February, vol. 33, pp. 153-154.] 6 philosophical society of washington. 296th Meeting. January 29, 1887. The President in the Chair. Thirty-six members present. Announcement was made by the President of the death of Gen- eral William B. Hazen, a member of the Society, which took place at 8 p. m., January 16. Mr. F. W. Clarke read a paper entitled THE PRESENT STATUS OF MINERALOGY. [This paper is expected to appear in the Popular Science Monthly.] A paper by Mr. R. T. Hill, entitled THE TOPOGRAPHY AND GEOLOGY OF THE CROSS TIMBERS OF TEXAS, was then read by Mr. W J McGee, as Mr. Hill had been called away from the city after his paper was placed upon the programme. [This paper appeared in full in the American Journal of Science, 3d series, 8°, New Haven, 1887, April, vol. 33, pp. 291-303.] 297th Meeting. February 12, 1887. The President in the Chair. Forty-one members and guests present. The President announced that Mr. Frank Hall Knowlton had been elected to and had accepted membership in the Society. A letter was read from the secretary of the Anthropological Society announcing that Mr. Alfred Russell Wallace would deliver an address Tuesday evening, February 15, on " Social versus Polit- ical Economy" before the Anthropological Society, and inviting the members of the Philosophical Society and their friends to be present on that occasion. Mr. H. A. Hazen made a communication on THE SKY GLOWS OF 1883. This communication was discussed by Messrs. Paul, E. Far- quhar, Winlock, and the author. GENERAL MEETINGS. 7 Mr. Bailey Willis presented a paper on THE TOPOGRAPHY AND STRUCTURE IN THE BAYS MOUNTAINS, TENNESSEE. [This paper appeared in the School of Mines Quarterly, Columbia Col- lege, 8°, New York, 1887, April, vol. 8, No. 3, pp. 242-252.] Mr. G. Brown Goode made a communication on THE GEOGRAPHICAL DISTRIBUTION OF SCIENTIFIC MEN AND IN- STITUTIONS IN THE UNITED STATES. [An abstract of this communication appeared in The Epoch, 4°, New York, 1887, June 24, vol. 1, pp. 467-468.] 298th Meeting. February 26, 1887. The President in the Chair. Thirty-nine members and guests present. The President announced the election to and acceptance of mem- bership of Mr. Franklin Austin Seely. Mr. C. V. Riley read a paper upon our city shade-trees, their foes and their future, illustrated by drawings and specimens. [This paper was afterwards elaborated and published as Bulletin No. 10 of the entomological division of the Department of Agriculture, published May 7, 1887, with the following title : U. S. Department of Agriculture. Division of Entomology. Bulletin No 10. Our shade-trees and their insect defoliators. Being a consideration of the four most injurious species which affect the trees of the capital ; with means of destroying them. By C. V. Riley, entomologist. Washington : Government Printing Office, 1887. 69 pp., 8°, illustrated.] This communication was discussed by Messrs. Gilbert, Mer- riam, and Elliott. 8 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. Lester F. Ward made a communication entitled THE FREQUENCY OF COINCIDENCES. [Abstract.] Every one is constantly meeting with coincidences in every-day life, but few ever take the trouble to record them. Mr. Ward had always been struck by their frequent occurrence and remarkable character, but until witbin about fifteen years had been content, as most people are, to allow them to pass with only a momentary expression of surprise. Certain comments upon them, however, which he had met with in the writings of Auguste Comte and Dr. George M. Beard had led him to take a wider view of their signifi- cance and to commence in the year 1875 the practice of jotting down in his note-book some of the more interesting and striking of them. In this way a large collection of instances had accumulated, a few of which were selected for presentation to the Society. These were read directly from his notes, without change of phraseology, in order to preserve their literal accuracy. Most of them were of a character which, according to the mathematical law of probabil- ities, would not occur again within any finite limitation of the events with which they were associated. The only application which it was attempted to make of the facts was to point out their bearing upon the investigations which had been recently conducted by the British Society for Psychical Re- search, from which, in Mr. Ward's opinion, unwarranted conclu- sions had been drawn, and which, he believed, receive their true explanation only when the frequency of coincidences is fully recog- nized. This communication was discussed by Messrs. Woodward and Clarke. 299th Meeting. March 12, 1887. The President in the Chair. Thirty-four members and guests present. The President announced the death on March 5th, at Pensacola, GENERAL MEETINGS. 9 Florida, of Capt. Edward Phelps Lull, U. S. Nm a member of this Society. The President also announced that Mr. Herbert Couper Wil- son had been elected to and had accepted membership in the Society. Mr. G. E. Curtis read a paper on THE THEORY OF THE WIND-VANE. [This paper appeared in the American Journal of Science, 3d series, 8°, New Haven, 1887, July, vol. 34, pp. 44-52. It has also been reprinted in the American Meteorological Journal, 8°, Ann Arbor, Mich., 1887, Sep- tember, vol. 4, No. 5, pp. 215-224.] Mr. H. A. Hazen thought that Mr. Curtls's formuloe showed that a single-tailed vane is more sensitive than a doubled-tailed one and would define a sensitive vane as that one which most quickly assumes the direction of the wind. Mr. Bates regarded these formula?, presented by Mr. Curtis, which had been deduced for inelastic fluids moving in right lines as inapplicable to elastic fluids moving in curved lines and often affected by vortices. Further remarks were made by Messrs. Abbe, Woodward, and Curtis. Mr. C. F. Marvin made a communication on the electrometer as used in observations of atmospheric electricity, exhibiting in connection with it a diagram and the instrument itself. Mr. Bailey Willis made a communication on the development of a perspective map from a contour map, illustrated by three sketches and diagrams. Mr. W. D. Johnson exhibited and explained a new plane table, presenting a number of improvements, especially as to increased stability, compactness, levelling, and mode of attaching the paper to the board. 10 philosophical society of washington. 300th Meeting. March 26, 1887. The President in the Chair. Seventy-one members and guests present. This meeting was held in the Assembly Hall of the Cosmos Club, southeast corner of H street and Madison Place, the Club having offered the use of its hall as a meeting place for the Society. Pre- ceding meetings during this year and during several former years, were by the courtesy of the Surgeon General of the United States Army, held in the library of the Surgeon General's Office on the east side of 10th and between E and F streets N. W. The President briefly alluded to this removal to more commodi- ous quarters upon the 300th meeting of the Society as marking an epoch in its history. Announcement was made of the election to membership of Mr. Samuel Pierpont Langley and Mr. Harry King. Mr. H. A. Hazen read a paper upon the RELATION BETWEEN WIND VELOCITY AND PRESSURE, illustrated by an apparatus resembling that used by him in recent experiments at the Smithsonian Institution. [This paper appeared, in the American Journal of Science, 3d series, 8°, New Haven, 1887, October, vol. 34, pp. 241-248.] The paper was discussed by Messrs. Billings, Woodward, Harkness, Paul, and the author. Mr. Bailey Willis made a communication on MT. RAINIER AND ITS GLACIERS, illustrated by perspective drawings of Rainier and Shasta, derived from contour maps by the method explained at the last meeting. The facts brought out by the illusti-ations and remarks indicate that Rainier was a point of intense volcanic activity long since extinct, and Shasta one of long continued less violent eruption. Rainier is a ruin, Shasta a complete cone. GENERAL MEETINGS. 11 Mr. Diller followed with an account of Mt. Shasta, contrasting it with Mt. Rainier. These communications were discussed by Messrs. Button and Willis. Mr. Marcus Baker made a communication entitled WHAT IS A TOPOGRAPHIC MAP? [Abstract.] Referring to the volume of testimony taken by a joint committee of the two houses of Congress charged with the duty of investigating the relations of certain scientific bureaus, Mr. Baker remarked that the time seemed opportune to discuss dispassionately certain points previously discussed controversially. Great diversity of view and of usage as to what constitutes topog- raphy, topographic survey, topographic map, etc., was brought out by citations from various authors and witnesses. According to some, the relief of a portion of country constitutes its topography; according to others, relief, drainage, and culture together make up topography ; still others find that the delineation or representation of such features constitutes topography. Topog- raphy is also defined as " description of places " and as " a branch of surveying." A rather large and mixed assortment of maps was exhibited. These maps, made by different nations, on different scales, in differ- ent styles and colors, with different conventions and symbols, and differing as to accuracy and completeness, were offered as samples of a very large assortment, which it was proposed to classify. "Topographic maps" should form one of the various classes into which it would be desirable or convenient to divide maps. To de- termine what principles should be adopted as guides for including or excluding from this class was the object of the enquiry. It was suggested that a satisfactory definition of " topographic map" must take account of four things, viz.: (a) scale. (b) purpose. (c) features to be represented. (d) accuracy. 12 PHILOSOPHICAL SOCIETY OF WASHINGTON. (a) Maps on a very small scale may be called generalized maps, and, though showing topographic features as firily and completely as the scale will permit, are still not properly^topographic but gen- eralized maps. Maps on very large scales, on the other hand, though sometimes containing curves of equal altitude or contours, are yet rather dia- grams or plans than topographic maps. The topographic map requires a scale somewhere between the small scale generalized map and the very large scale plan. (b) The class to which any given map must be referred further depends upon its purpose. If the purpose is to exhibit the geologic structure, it is a geologic map ; if designed for military purposes, a military map; if for nautical purposes, a nautical map—or, as it is called, a chart—and if for exhibiting the topography, a topographic map. If a topographic map is colored to exhibit the geologic structure of the region shown, it is no longer a topographic but a geologic map, etc. Most of the maps of the Coast Survey, though exhibiting more or less topography, would not be classed with topo- graphic maps, but with charts, being designed for nautical pur- poses. (c) The features to be exhibited on a map, in order that it may be classed as topographic, are (1) the relief, (2) the drainage, in- cluding in this term the whole water system of ponds, lakes, swamps, streams, etc., and (3) the culture, this term implying the works of man of such size or importance as to warrant their being classed as topographic features. What features are topographic depends upon the scale of the map. (d) With respect to accuracy we shall have topographic maps and topographic sketches. A topographic sketch controlled by locations is a topographic map; not so controlled, it remains a sketch. This communication was discussed by Messrs. G. Thompson, H. Farquhar, R. D. Mussey, and the author. general meetings. 13 301st Meeting. April 9, 1887. The President in the Chair. Seventy-three members and guests present. Prof H. Carrington Bolton, of Hartford, Conn., read, by in- vitation, a paper on the COUNTING-OUT RHYMES OF CHILDREN, THEIR ANTIQUITY, ORIGIN AND WIDE DISTRIBUTION. [Published in a volume of same name by Elliot Stock, London. Also read before the New York Academy of Sciences.] This paper was discussed by Messrs. Eastman, Billings, Mus- sey, Hazen, Ward, Mason, Edward Eggleston, Babcock, and by the author. In the course of the discussion several new rhymes were brought forward together with many interesting references to particular customs and formulas of speech. 302d Meeting. April 23, 1887. The President in the Chair. Sixty members and guests present. Mr. Harkness presented a communication ON A DEVICE FOR VIEWING THE SUN BY LIGHT OF ANY DESIRED WAVE LENGTH. [Abstract.] If two precisely similar prisms are placed in contact, with their refracting angles facing in opposite directions, the outer surfaces of the combination will be parellel to each other, and light falling upon the first prism will emerge from the second parallel to its origi- nal direction and without suffering any dispersion whatever. So long as the two prisms remain in contact the combination is, in effect, a piece of thick piano-parallel glass, and objects seen through it present only their natural colors. If, however, the prisms are separated by a considerable interval a different action occurs. A 14 PHILOSOPHICAL SOCIETY OF WASHINGTON. small pencil of nearly parallel rays falling upon the first prism then suffers so much dispersion before reaching* the second prism that the latter can no longer reunite the rays of different wave- lengths, but it will still render them parallel to the directions they had before entering the fir3t prism. Thus all the conditions neces- sary for affording distinct vision of the radiant to an eye situated behind the second prism are fulfilled, and at the same time the wave-length of the light received by the eye can be completely con- trolled by the adjustment of the prisms. In the experimental apparatus actually constructed two sixty- degree prisms were employed, separated by an interval of thirty- eight inches. These prisms were fixed relatively to each other, and behind the second one a viewing telescope of 6.5 inches focal dis- tance and 0.84 of an inch clear aperture was mounted in such a way that it could be moved through an arc sufficient to bring rays of any desired wave-length to the center of its field. Slits were placed immediately behind the first prism and before the objective of the viewing telescope. Thus arranged, the instrument gave images of the whole sun composed of tolerably homogeneous light ; but the image of the surrounding sky was not composed of homoge- neous light, and to remedy that defect a somewhat different arrange- ment of the slits will be tried. This communication was followed by a symposium upon the ques- tion, WHAT IS TOPOGRAPHY? participated in by Messrs. M. H. Doolittle, W. D. Johnson, H. G. Ogden, and Gilbert Thompson. Mr. Doolittle began by declaring his ignorance until recently of the subject and his resulting fitness to investigate without preju- dice. He then pointed out the origin and development of the terms geography, chorography, and topography, referring to the death of the term chorography at the ripe old age of 1,500 years or there- abouts and the alteration with time of the meaning of the words geography and topography. The early meaning of topography, description of places, appears to be obsolete or obsolescent. The existing confusion concerning the meaning of the word topography was made strikingly manifest by quotations from dictionaries. GENERAL MEETINGS. 15 Mr. W. D. Johnson followed with a written communication, in which he took the ground that topography had within recent years lost almost or quite completely its old significance of description of places, and was now almost universally understood to refer to sur- face forms, the ups and downs, the hills and valleys, etc., and to nothing else. This position was defended by very diverse and numerous citations. Mr. H. G. Ogden followed with a written communication, in which he argued that the topographical features which, taken to- gether, constitute topography, comprise not only natural relief, but artificial relief also, such as railway cuts and embankments, dams, mounds, etc., and that generally hills and valleys, streams and ponds, towns and roads, etc., should be, as they have been, regarded as topographical features. Mr. Gilbert Thompson held that permanent hill features alone constitute topography, and set forth the general applicability of this view by illustrative crayon drawings. A general discussion followed, participated in by Messrs. W. D. Johnson, G. Thompson, Doolittle, Winlock, Harkness, E. Farquhar, and M. Baker. 303d Meeting. May 7, 1887. The President in the Chair. Forty-four members and guests present. Announcement was made of the election to membership of Mr. Harry Vanderbilt Wurdemann. Mr. J. W. Chickering read a paper on THE MUIR GLACIER, ALASKA, illustrated by a map and diagram. Mr. Marcus Baker commented on this communication and re- marked that in a careful inspection of the shores of Lynn Canal in 1880 he was unable to discover more than a small proportion of the glaciers reported by Mr. Muir. 16 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. C. Hart Merriam read a paper upon THE ECONOMIC PHASE OF THE ENGLISH SPARROW QUESTION. [This paper appeared in the Report of the Commissioner of Agriculture, 1886, 8°, "Washington, Government Printing Office, 1887, pp. 227-246; with map.] Respecting the law protecting sparrows Mr. Hazen drew atten- tion to the fact that a colored boy had recently been fined two dollars in the Police Court of Washington for throwing stones at sparrows. Mr. W J McGee made an oral communication entitled THE QUATERNARY DEPOSITS AND THE GREAT DISPLACEMENT OF THE MIDDLE ATLANTIC SLOPE, embodying the results of investigations set forth in part in a memoir on the geology of the head of Chesapeake Bay, contained in the Seventh Annual Report of the U. S. Geological Survey, and in part in an article entitled Three Formations of the Middle Atlantic Slope, which is expected to appear in the American Journal of Science for February and March, 1888. 304th Meeting. May 21, 1887. The President in the Chair. Forty-five members and guests present. Mr. C. E. Dutton made a communication on A RECENT VISIT TO THE SCENE OF THE CHARLESTON EARTH- QUAKE AND RESULTING CONCLUSIONS. Mr. W. H. Dall made a communication entitled SOUTH FLORIDA NOTES. Remarks on this communication were made by Messrs. Bou- telle, Head, and Toner. Adjourned to October 15. GENERAL MEETINGS. 17 305th Meeting. October 15, 1887. The President in the Chair. Fifty-one members and guests present. The President announced the death at Wood's Holl, Massachu- setts, on August 19, 1887, of Prof. Spencer Fullerton Baird, one of the original members of the Society. Mr. C. E. Dutton made a communication ON THE DEPTH OF EARTHQUAKE FOCI. [Abstract.] Mr. Dutton first referred to the various methods which had been resorted to in order to ascertain the depths of earthquake foci. The method suggested by Mallet and based on the assumption that the lines of fracture in the walls of buildings tended to arrange them- selves transversely to the direction of propagation, he believed to be unavailable and not sustained by observation. The motions of buildings 'and of the ground itself during an earthquake were highly complex, and, moreover, the lines of fracture, he believed, were influenced far more forcibly by the nature of the structure, the openings in the walls, and the natural directions of vibration than by the directions of the impulses themselves. Seebach's method, by ascertaining the variation of the speed of the wave along the surface of the ground in the vicinity of the epi- centrum, was regarded as impracticable, though the mathematical considerations upon which it was founded were doubtless correct. The speed of propagation is so high and the difficulty of obtaining time observations of sufficient precision is so great that this mode of solution must fail for want of the requisite data. Seebach seems to have been under the impression that this speed was not more than a very few hundred metres per second. The Charleston earth- quake was transmitted with a speed probably exceeding 5,000 metres per second, and Mr. Dutton was of the opinion that all true earth- quakes were propagated with a speed differing but little from that ; but, even if the speed were no greater than Seebach supposed, it 48 18 PHILOSOPHICAL SOCIETY OF WASHINGTON. would still be expecting too much of human fallibility to suppose that data of sufficient accuracy could ever be obtained. There is, however, a method which is dependent, not upon time data, but upon observations of intensity, which seems to offer the means of computing the desired quantity. It is well known that the intensity or energy per unit area of wave front diminishes as the wave moves outwards from the centrum. Like all radiant energy, it must be subject to the law of variation inversely as the square of the distance. If the elasticity of the medium were perfect and its density uniform the law would be rigorous. As a matter of fact, it is not so ; but, on the other hand, we are assured that the elasticity cannot be very imperfect, since if it were so the propaga- tion of impulses to very great distances would be impossible, and the waves would soon be extinguished in work done upon the me- dium itself. Nor is there reason to suppose that the variations of density are extreme. Thus, while the law of inverse squares may be in some measure impaired, it may still be assumed as an approxi- mate expression of the reality. If, then, we were able to form a just estimate of the rate of varia- tion of the intensity along lines radiating from the epicentrum, we should have the means of computing the depth of the focus. Thus, if O be the focus and E the epicentrum and P any point at a dis- tance from the epicentrum, the intensity at P would be inversely proportional to the square of O P. Calling EP = «) OP= r, and O E = q, and designating by a the intensity at unit distance and by y the intensity at any other distance x, we have the equation : a r ' q + x2 This equation corresponds to a curve whose figure is approxi- GENERAL MEETINGS. 19 mately represented in the diagram, and the curve will have a point of inflexion at which the decrease in the value of y as E P in- creases will be a maximum. Differentiating the equation twice and equating the value of the second differential coefficient to zero will give us the co-ordinates of this point of inflexion. The value of the abscissa of this point will be l/"3 From this value the constant a has disappeared, showing that it is independent of the intensity of the original shock and dependent upon the depth alone. The application of this analysis to the problem is as follows : As we recede from the epicentrum the inten- sity diminishes, but it does not diminish at a uniform rate with the distance. There is some critical distance from the epicentrum at which the rate of decrease of intensity has a maximum value. This critical distance depends upon the depth of the focus and upon nothing else, and the magnitude of this distance is equal to the depth divided by l/3, and, conversely, the depth of the focus is equal to the critical distance multiplied by 1/8. If, then, we can locate the epicentrum and the points where the intensity diminishes with greatest rapidity, we have at once the means of determining the depth of the focus. In the case of the Charleston earthquake this location has been approximately made and a depth of about twelve miles has been deduced for the focus of the principal shock. After a description of Mallet's second method of investigation by the observation of the overturning power of earthquakes, the sub- ject was discussed by the President and by Messrs. H. Farquhar, Gilbert, and Dutton. Mr. F. W. Clarke made an oral communication on the MANCHESTER MEETING OF THE BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE, 1887. Remarks upon this communication were made by Mr. Abbe. 20 philosophical society op washington. 306th Meeting. October 29, 1887. The President in the Chair. Forty-one members and guests present. Announcement was made by the President of the election to and acceptance of membership of Mr. Jesse Herman Holmes. The President also referred to the loss sustained by the scientific world in the death of Prof. Spencer F. Baird, and announced that the General Committee had taken the preliminary steps for arranging a memorial meeting in commemoration of his life and scientific work. Mr. Cleveland Abbe read the following paper entitled THE SIGNAL SERVICE BIBLIOGRAPHY OF METEOROLOGY. Mr. Abbe stated that in 1872 he began, at his own expense and for personal use, a more systematic collection of the titles of works bearing upon all subjects that he was interested in, especially meteorology. After corresponding in 1874 with the committee of the Royal Society as to the probability of the publication of their proposed subject-index to their Catalogue of scientific papers^ and being officially informed that this work would not be under- taken, he decided to complete his systematic examination of all the titles in that great work and copy the appropriate ones for his own use. In 1878, when this work was nearly completed, so far as regards the first six volumes, he addressed a note to Prof. Hann, of Vienna, stating what he had done and inquiring whether any one in Europe was similarly engaged. Almost simultaneously with this Prof. Hann received and published 1 a letter from Dr. Hell- mann, of Berlin, dated January 10, 1879, urging the importance of a general index to the literature of meteorology. This letter had evidently been suggested by a circular issued in October, 1878, by the permanent committee of the first meteorological congress at Vienna, proposing a programme for the second congress about to be held at Rome in the approaching month of April, 1879. In this circular the committee asked that the delegates prepare catalogues ^tschr. Met., Wien, 1879, xiv, 9G. GENERAL MEETINGS. 21 of the meteorological observations, published or unpublished, for their respective countries. At the Rome conference Dr. Hellmann's letter was presented on April 21 and by the congress referred to the newly-appointed Inter- national meteorological committee. The congress also adopted resolutions2 asking the delegates to prepare lists of the observations for their respective countries, and the directors of meteorological libraries to add lists of the works not found in the published library catalogues of the Meteorological society of London and the observ- atory at Brussels, or in Mr. Abbe's cards. After the meeting at Rome Mr. Abbe received a letter from Dr. Hellmann, to which he replied August 22, 1879, offering to co- operate in the preparation of a general bibliography and to transfer his cards either to the International meteorological committee or to Dr. Hellmann personally, on the repayment of his expenses. At the same time a similar offer was made to General Myer, Chief signal officer, under the impression that the latter would be pleased to complete the work as an official matter. At the first or Berne meeting of the International meteorological committee in August, 1880, letters of Dr. Hellmann were read dated January 20 and July 20, 1880, giving a detailed scheme for combining the various works and for the preparation of a catalogue, and embodying Mr. Abbe's proposal of August, 1879, as well as a similar one from Mr. G. J. Symons of London3 . The committee, however, resolved that each country be requested to furnish lists of observations and that Messrs. Scott and Hellmann be a sub- committee to consider the means of carrying out Dr. Hellmann's scheme.4 In the fall of 1881, Mr. Abbe wrote to Mr. Symons for more de- tails as to his work. Mr. Symons' reply and Mr. Abbe's renewal of his previous offer were then laid before General Hazen, Chief signal officer, who decided to purchase the catalogues of both these gentlemen with a view to their combination and completion by the Signal office in case the International committee did not do this. In November, 1881, Mr. Symons was authorized to prepare at the expense of the Signal office, a copy of all meteorological titles in his 2 Rep. pr. internat. meteoral. cong. Rome 1879, Lond., 1879, p. 21, 75. 3 Rep. pr. internat. meteoral. comm. Berne 1880, Lond., 1881, p. 38, 40. 4 Ibid., p. 8-9. 22 PHILOSOPHICAL SOCIETY OF WASHINGTON. collection, and in December, 1881, M Abbe's cards were pur- chased. Mr. Synions' catalogue was received in October, 1883, and on March 4, 1884, Mr. C. J. Sawyer, librarian of the Signal office, was relieved from the care of the library, and, as bibliographer, ordered to devote his whole time to the completion of this work, which was then transferred from the library to the study room division of the Signal office. At the second meeting of the International meteorological com- mittee, at Copenhagen, in August, 1882, Messrs. Scott and Hell- mann reported that the Meteorological office could not print the proposed catalogue and that subscriptions were not practicable. They therefore recommended each meteorological service to publish a national bibliography, for which Hellmann's Repertorium der deidschen Meteorologie, prepared in accordance with the ideas of the committee and now just about to be published, should serve as a model. It need only be added that since 1882 the International meteorological committee have, with other meteorologists, acqui- esced in the arrangement by which the Signal service has under- taken to complete and, if possible, publish for its own and for gen- eral use a general index to the literature of meteorology. The importance of this work is especially endorsed by General Greely, who, in his current annual report, October, 1887, as Chief signal officer, says : The practical value of such a bibliography has been fully shown by its constant use in current office work, and, in addition to the official demands, almost daily calls for information have been re- ceived from parties not connected with the service. The result of this work is the collection of special bibliographies, which ensures those consulting it a complete index of what has been accomplished in each special line of meteorology. As has been well said, the progress of meteorology is retarded and labor therein wasted owing to the impossibility of ascertaining what has been done in its various branches—an experience which, as scientific men well know, is by no means confined to this science. The cost of time and labor to the Government for the preparation of this work cannot be less than $12,000 to $15,000, and the result of these labors has been the com- pletion of a work which is of great value, both practically and sci- entifically, to the entire world. The catalogue in its present condi- tion is valuable, and sufficient for the pressing needs of this service, but to view it in this light would evince a narrow and selfish dispo- sition not in keeping with the scientific spirit of the age. At a cost GENERAL MEETINGS. 23 of probably $8,000 or $10,000 this work can be printed and dis- tributed to the world as a monument and evidence of the growing scientific tendency of this nation. If such action is taken by Con- gress, the Chief Signal Officer has no doubt, from the willing spirit and hearty co-operation shown by leading scientists of other coun- tries, that future international co-operation will secure, by a system of rotation, from the various European governments the publication of a series of supplements which will keep the world abreast of the steadily increasing volume of meteorological publications. A large number of American and foreign meteorologists and librarians have given largely of their time and energy in the compilation of this bibliography, as is shown by the fact that over one-half of the mate- rial has been contributed from foreign countries, so that the bibli- ography represents not only a large expenditure on the part of the United States, but also many years of additional gratuitous labor. The material could not be duplicated, and it would seem but a re- spectable reciprocity of exchange that the Government should print the catalogue, so as to enable the voluntary contributors to avail themselves of the complete work. This fulfilment of obligations to contributors by a public catalogue is an act of justice ; but, in addi- tion, it should be considered that this bibliography will be of great practical value to the agricultural, commercial, engineering, and medical interests not only of the United States, but of the world. Mr. Abbe stated that he had asked Mr. Sawyer to present to the Philosophical society some account of his Avork, now nearing com- pletion, but, as he could not be present, Mr. Abbe read the following memorandum prepared by Mr. Sawyer : MEMORANDUM ON THE SIGNAL SERVICE BIBLIOGRAPHY OF METEOROLOGY AND TERRESTRIAL MAGNETISM. The bibliographical work of the Signal office dates from 1881, and officially originated in correspondence begun by Prof. Abbe with Prof. G. J. Symons, of London, Dr. G. Hellmann, of Berlin, and Dr. A. Lancaster, of Brussels, who all manifested the greatest interest in the proposed catalogue and have been the most impor- tant contributors to it. The meteorological titles in the Catalogue of scientific papers. Compiled by the Royal society of London, vols, i-vi (1800-1&63), had already been selected and extracted by Prof. Abbe and were trans- ferred to the Signal office in December, 1881, on the repayment of the expenses incurred by him in the work. At the request of the Signal office. Prof. Symons undertook to furnish copies of all titles on meteorology and terrestrial magnetism contained in his extensive 24 PHILOSOPHICAL SOCIETY OF WASHINGTON. collection of titles on astronomy, meteorology, and allied sciences, the expense to the office to be only his actual outlay for clerical assistance. Prof. Symons' catalogue already represented many years of bibliographical research, and to it he now added many titles, securing the co-operation of European meteorologists by per- sonal visits and by correspondence, and including the more impor- tant English libraries. This catalogue was received late in 1883, about two years having been spent in its compilation ; it consisted of about 18,000 titles chiefly of separate works, and may be considered as the foundation of the present bibliography. No further work was done until March, 1884, when an effort to secure the services of Prof. Lancaster having failed, the librarian of the Signal office was assigned to the work of preparing the catalogue for publication. The original intention had been to extend Prof. Symons' work only by the combination of titles from the Royal Society catalogue including those in vols, vii and viii (1864-1873), selected but not yet copied by Prof. Abbe, the catalogue to be arranged by authors and to form only a first contribution to the general meteoro- logical bibliography desired. But the large amount of material on hand, and the conviction that some recent contributions to the subject, especially the Reper- torium der deutsehen Meteorologie by Dr. Hellmann, should be in- cluded, and that the periodical literature previous to 1800 and subsequent to 1873 should be represented, led to the consideration of an enlargement in the scope of the work. It was foreseen that the necessary delay in securing an appropriation for publication would afford opportunity for still further extension, and it was decided March 15, 1884, to complete the compilation so far as possible without postponing publication for this purpose and to issue an approximately complete general bibliography, of such form as to serve as a basis for supplementary volumes. In pursuance of this plan, every effort has been made to secure contributions, especially by indexing periodicals, by examination of printed and manuscript catalogues and bibliographies, and by cor- respondence with meteorologists and librarians. The lacunse in periodical literature have been filled by indexing all periodicals available previous \o 1800 and subsequent to 1873, and by the examination of all indexes, bibliographies, &c, avail- able, such as Reuss, Young, Poggendorff, Kerl, Fortschritte der GENERAL MEETINGS. 25 Physik, and many others. It was found that the general indexing of the Royal society for the period from 1800 to 1873, was not full enough for this special bibliography, and all periodicals rich in meteorological literature were reindexed. The International meteorological committee had already consid- ered the subject of meteorological bibliography, and, uuable to secure at once the publication of a general bibliography, had recommended that each country compile a list of its own observations and that special national bibliographies be prepared wherever possible. Some work had been done in accordance with this recommendation, especially in Germany and Russia, and an attempt was made by the Signal office to secure the extension of this work and to obtain from foreign meteorologists and librarians, bibliographies for their respective countries. The great interest in the work was shown by the hearty co-operation from all sections. Among the special bibliographies received the following may be mentioned as among the most complete and valuable : Germany, by Dr. Hellmann ; Japan, by Dr. Knipping ; Norway, by Prof. Mohn ; Poland, by Prof. Karlinski ; Portugal, by J. C. de Brito-Capello ; Roumania, by Dr. Hepites ; Russia, by Profs. Wild and Woeikof; South Africa, by Dr. Gamble ; Sweden, by C. G. Fineman amd C. Annerstedt ; Victoria, by R. L. J. Ellery. All the meteorological libraries of the world are represented, in- cluding, as worthy of special mention, those of the Meteorological office and Royal Meteorological Society, of London ; the Societe meteorologique de France, Paris ; the large manuscript collection of Prof. Poey, the Ronald's, Poulkova, and Brussels catalogues, all contained in the catalogue of Prof. Symons ; the Deutsche Seewarte, Hamburg (including the library of the late Prof. Dove), and the k. k. Central-Anstalt, of Vienna (with that of Prof. Hann\ added by the Signal office. The number of scientific and general libraries represented is very large. Letters, requesting lists of their works, were sent to about 400 writers (exclusive of those in Germany, where this method had been employed by Dr. Hellmann), and the replies received have been of the greatest value in the representation of living authors. The desirability of securing as great completeness as possible, the expectation of an early publication, and the fact that the Symons and Hellmann catalogues ceased with 1881, led to the adoption of this date as the close of the bibliography, and the following state- 26 PHILOSOPHICAL SOCIETY OP WASHINGTON. ment of the titles on hand includes only those of works published before January 1, 1882. A large amount of material for subsequent years has been collected but has not been submitted to classification. It may be included in supplementary volumes, or incorporated with the bibliography if publication be delayed. The chief sources of material and approximate number of titles added to the bibliography, after the rejection of duplicates, are as follows : Prof. Symons' catalogue ...... 18,000 Royal Society catalogue, i-viii ..... 11,000 Hellmann, Repertorium ...... 5,000 Printed catalogues and bibliographies, including Eeuss, Poggendorff, &c. (400 vols.) ....... 4,000 Manuscript catalogues and bibliographies .... 3,000 Periodicals indexed (6,400 vols.) ..... 12,000 Total number before final revision . Number of independent titles after final . 53,000 revision, about 50,000 The duplication of titles by double classification will increase the number of entries to about 55,000. The form adopted for the work is that of a classed subject cata- logue, with full author index. The general plan of the subject catalogue is similar to that of the Poulkova catalogue and that adopted by Drs. Houzeau and Lancaster for their Bibliographie generate de I'astronomie, the arrangement being chronological under each subject. The classification is based upon a scheme submitted by Dr. Lancaster, at the request of the Signal office, some minor modifications having been made after careful study and consulta- tion with other meteorologists and bibliographers. The general divisions of the classification are shown by the fol- lowing outlines : I. General meteorology. A. History and bibliography. B. General and collected works. C. Organization and methods. D. Instruments. II. Theoretical me- teorology. fl. Temperature. T>1 . j. ., , 2. Moisture, f A. Physics of the at- ! g Pres8Ure> mosphere. j 4 Qptical phenomena 15- " LO. Mechanics of the atmosphere. Cosmic relations of meteorology. Electrical phenomena. 1. General circulation. !1. 2. Winds. 3. Storms. IV. Terrestrial magnetism. - GENERAL MEETINGS. 27 (A. Weather prediction. B. Agricultural meteorology. C. Medical meteorology. ^ D. Climatology. A. General. B. Observations, instruments, and methods. C. Variation. D. Distribution. i E. Connection with meteorology. V. Observations (meteorological and magnetic) classed geographically. These have been largely subdivided, the number of divisions em- ployed in the preliminary classification being 169. This number will be varied somewhat in revision, the final classification depend- ing largely on the number and character of the titles in each class. The following example will indicate the character of the subdi- vision : 1. General. 2. Description. 3. Height. II. A. 6. f. Aurora. -{ 4. Frequency. 5. Periodicity. 6. Connection with meteorological phenomena. 7. Connection with terrestrial magnetism. The classification has been from originals, where possible, and all resources of the libraries available have been used for this purpose. Where access to the work or article was not possible, correspondence was maintained for the explanation of doubtful titles. The assign- ment of cards to their subjects has been completed, but they are not yet arranged under their respective heads. Consequently, no state- ment of the number of titles under each class can yet be made, but a rough estimate shows that of the 50,000 titles about 5,000 will be under observations and 3,000 under terrestrial magnetism, leaving about 42,000 entries for meteorological discussions. The author index is similar to that adopted by Drs. Houzeau and Lancaster, giving under the full name of the author, and for each title, an abbreviation of the subject under which it is classed, the date of publication, and the reference. Tbe index, as completed, contains about 12,500 authors, or an average of four independent titles for each author. A biographical note may be included under each author. The bibliography will be completed early in 1888, the only work now remaining being arrangement by subjects, revision, sub-class- 28 PHILOSOPHICAL SOCIETY OF WASHINGTON. ification of observations, preparation of subject index and periodical list. The technical preparation of copy will follow when the appro- priation for publication is made. This communication was discussed by Messrs. Mann, Fletcher, Marcus Baker, Gilbert, and the author. Mr. Lester F. "Ward made a communication ON THE GEOGRAPHICAL DISTRIBUTION OF FOSSIL PLANTS, illustrated by a map. [This paper will appear in full in the Eighth Annual Report of the U. S. Geological Survey, for the fiscal year 188G-'87.] 307th Meeting. November 12, 1887. The President in the Chair. Fifty-two members and guests present. Announcement was made by the President of the election to and acceptance of membership of William Henry Babcock. Mr. C. E. Dutton presented a communication which had been jointly prepared by himself and Mr. S. Newcomb on THE SPEED OF PROPAGATION OF THE CHARLESTON EARTHQUAKE. [This paper appeared in full in The American Journal of Science, 3d series, 8°, New Haven, 1888, January, vol. 85, pp. 1-15.] This paper was briefly discussed by Mr. Clark and Mr. Dutton. Mr. Harkness read a paper ON THE REPRESENTATION OF COMET ORBITS BY MODELS, illustrated by card-board models. [This paper appeared in The Sidereal Messenger; conducted by Wm. W. Payne. 8°. Northfield, Minn., Carleton College observatory, 1887, Decem- ber, vol. 6, No. 10, pp. 329-349.] GENERAL MEETINGS. 29 308th Meeting. November 26, 1887. The President in the Chair. Fifty members and guests present. A circular letter from the New York Academy of Sciences, re- questing co-operation in erecting a monument to the memory of the ornithologist Audubon, was laid before the Society by the Secretary. Mr. G. K. Gilbert presented a communication entitled STATISTICS OF THE PHILOSOPHICAL SOCIETY FROM ITS FOUNDATION. [Abstract.] The following data, except when otherwise noted, are compiled from the published records of the Society.* The Society was organized March 13, 1871, with a membership of 44, and this was increased during the same year by the election of 17. In each succeeding year new members were elected, the smallest number being 8, : in 1876, and the largest 35, in 1884. Fi'om time to time members have been dropped from the list for non-payment of dues, others have died, and others resigned. The average annual number of new members has been 18. The total number of resignations has been 24. The membership has always been classified as i*esident and non-resident, or " active " and " absent." From time to time a list of the members has been pub- lished in the Bulletin, and since 1879 these lists have been annual. The following table shows the number of active members at each of the indicated dates. It also shows the gross annual accession to membership, and likewise the average attendance at ordinary meet- ings for each year, beginning with 1875, previous to which time the attendance is not noted in the published minutes. The year 1882 had the minimum attendance, 34, and 1887 the maximum, 49. The general average of attendance at meetings for the reading of papers is 40; at meetings for the election of officers, 36. *The paper, as read, did not include the statistics for 1887, which were necessarily imperfect at that time. The abstract for printing was brought down to December 21, 1887, the date of the annual meeting. Certain indi- cated data on membership were brought only to December 1, 1887. 30 PHILOSOPHICAL SOCIETY OF WASHINGTON. Table I. Membership and Attendance of the Philosophical Society, by Years. GENERAL MEETINGS. 31 The Anthropological Society was organized February 17, 1879, and has now a membership of 154. The Biological Society was organ- ized December 3, 1880, and has a membership of 174. The Mathe- matical Section of the Philosophical Society held its first meeting March 29, 1883. The Chemical Society was organized January 31, 1884, and now numbers 44 members. During the two years fol- lowing the institution of the Anthropological Society our Society witnessed maxima in the accession to membership, in the total membership, in the attendance, and in the ratio of attendance to membership. During the two years following the foundation of the Biological Society each of these quantities reached or passed a minimum. The year of the organization of the Mathematical Sec- tion was characterized by an increase of attendance, but not of membership. In the four years elapsed since the beginning of the Chemical Society our membership and attendance have steadily increased, their ratio remaining constant. If the relation of our record to the Biological Society only were considered, it would be easy to infer that our Society suffered from the formation of another scientific society, but a contrary inference would be drawn from a comparison of our record with the histories of the Anthropological and Chemical Societies, and in view of all the facts it appears proper to conclude that our membership and attendance have not been materially influenced by the organization of the other societies. The data of attendance have been, classified by months likewise and finally by half-months, with the result which appears in Table II. The data cover a period of 12 years, but are somewhat imper- fect. To diminish the error from imperfection of record, a general correction for annual phase was applied to all the observations — that is to say, they were all reduced to consistency with a mean attendance of 40. Only ordinary meetings for the reading of papers were included, and the year 1887 was omitted because the attend- ance appeared to be greatly affected by the change of quarters (March 26) from the Army Medical Museum to the Assembly Hall of the Cosmos Club. 32 PHILOSOPHICAL SOCIETY OF WASHINGTON. Table II. Average Attendance at Ordinary Meetings for Bach Half-Month, Compiled from Records for 11 Years, 1875-1886. March, first half 40.0 second half 40.8 first half 48.0 second half 40.3 first half 37.5 second half 37.3 first half 33.7 second half 28.6 October, GENERAL MEETINGS. 33 more of the selected classes have been entered in each, and such duplicate entries have been treated as integers and not as fractions. To an extent dependent on this treatment the deduced ratios are inaccurate. It should be observed that the selection of classes has depended largely on the nature of the material to classify. As the statistics grew out of the work of indexing the Bulletin, the selection was affected by the needs of the indexer, and as it was desired to learn the influence of the organization of other societies on the scope of our proceedings, the selection was affected by the classification of sub- jects among the other societies. The following is the classification : Group 1, Mathematics ; Group 2, Astronomy, including calendars ; Group 3, Physics, including molecular physics, electricity, acous- tics, optics, and microscopy, which last subject happens in the litera- ture of the Society to be almost entirely optical ; Group 4, Chemis- try and mineralogy ; Group 5, Meteorology and thermometry ; Group 6, Geology ; Group 7, Geography, including physical geography, surveying, and travel and exploration ; Group 8, Biology, includ- ing zoology, botany, and human anatomy and physiology ; Group 9, Anthropology, including ethnology, archaeology, psychology, an- thropometry, political economy, and social science and statistics; Group 10, Miscellaneous, chiefly technology, but including also biography and general philosophy. It will be seen that chemistry, biology, and anthropology are defined so as to include the scopes of the Chemical, Biological, and Anthropological Societies. For convenience of discussion, the period of 17 years covered by the statistics has been divided into five unequal parts, such that three of the lines of separation correspond with the epochs of commence- ment of the three sister societies. The time divisions begin on the years 1871, 1875, 1879, 1881, and 1884, and contain, respectively, 4, 4, 2, 3, and 4 years. At the end of the second the Anthropological Society was established, at the end of the third the Biological, at the end of the fourth the Chemical. The Mathematical Section was organized one year before the Chemical Society. For each time division the number of papers of each class was ascertained, and from these numbers were computed the percentages which appear in Table III. 49 34 PHILOSOPHICAL SOCIETY OF WASHINGTON. Table III. Percentages of Papers on Different Subjectsfor Different Periods. Subjects. 1. Mathematics 2. Astronomy 3. Physics 4. Chemistry 5. Meteorology 6. Geology 7.' Geography 8. Biology 9. Anthropology 10. Miscellaneous Periods. 1871- 1874. 1875- 1878. 6 23 10 4 9 6 15 9 6 12 100 5 18 14 2 5 8 13 9 15 11 100 1879- 1880. 2 18 12 6 4 9 7 10 19 13 100 1881- 1883. 9 7 12 1 13 14 7 9 11 17 100 1884- 1887. 2 6 9 4 11 27 10 6 13 12 100 1871 to 1887. 5 16 11 3 8 13 11 8 12 13 100 It appears from this table that in the two periods previous to the organization of the Anthropological Society the subject of anthro- pology furnished first 6 and then 15 per cent, of our material, and in the following periods it furnished 19, 11, and 13 per cents. Biol- ogy furnished in the first three periods 9, 9, and 10 per cents., and after the beginning of the Biological Society 9 per cent, and 6 per cent. The percentages of chemistry for the first four periods are 4, 2, 6, and 1, and for the single period of four years since the organization of the Chemical Society, 4. These figures show that the organiza- tion of scientific societies devoting themselves to the cultivation of special scientific fields has not materially affected the interest of our Society in the same sciences, so far as that interest may be judged by the number of communications presented. The table is not arranged to exhibit the effect upon our general meeting of the institution of the Mathematical Section, but an inde- pendent computation has been made with the following result : In 12 years previous to the Mathematical Section the Society listened to 28 mathematical papers, an average of 2.3 per year. In the five years following the general meeting listened to six mathematical papers, an average of 1.2 per year. While the amount of mathe- GENERAL MEETINGS. 35 matics before the Society in general meeting has been greatly dimin- ished, the subject has not been entirely eliminated. The general fact appears to be that the Philosophical Society, being composed partly of men with a wide interest in scientific matters and partly of specialists in many scientific branches, affords a fitting arena for the discussion of subjects of general scientific interest, but is not equally adapted to the presentation of highly specialized researches. By a process of natural and unconscious selection it has discountenanced those papers which from their nature can interest only the devotees of a single science, and it, therefore, has not fully met the needs of the scientific community of Washington. The natural and proper result has been the institu- tion, without and within the Society, of organizations undertaking the cultivation of narrower fields, and these have found material of their own without detraction of material which natually came to us. In anthropology, in biology, in chemistry, and in mathematics we still receive the communications which have a broad interest, and, as such papers are largely written from a philosophic point of view, it may well be that we are gainers by the multiplication of organi- zations. But while the modifications which have occurred in the ratios in which various subjects have been represented on the floor of the Society do not indicate an important yielding of our program to outside influence, they do indicate progressive tendencies in other directions. Astronomy, which during the first period was the lead- ing theme, with a j)ercentage of 23, has fallen, through 18, 18, and 7, to 6 per cent.; geography, with 15 per cent, and 13 per cent, for the first two periods, has 7, 7, and 10 for the last three. Geology, on the other hand, with 6 per cent, at first, has increased steadily, through 8, 9, and 14, to 27 per cent., and anthropology and meteor- ology, while exhibiting fluctuations, have on the whole increased their percentages. During the first period astronomy and geography together gave 5 times as many papers as geology ; during the last period their combined volume is only two-thirds that of geology. The general explanation is not far to seek. Geology has gained in importance on the floor of the Society because of the rapid growth of the Geological Survey, which has brought to the city and to the Society a large number of geologists. The increased attention oi the Society to meteorology is traceable to the establishment of the Study Room of the Weather Bureau, and the increase in anthro- 3G PHILOSOPHICAL SOCIETY OF WASHINGTON. pology is correlated with the growth of the Bureau of Ethnology. The great modification in the relative attention given to different subjects is due to the large amount of new blood acquired by the Society. The statistics of the Mathematical Section are exhibited in the following table : Table IV. Statistics of the Mathematical Section from its Establishment to 1887. Year 1883. 1884. 1885. 1886. 1887 Number of meetings Number of communications Average attendance Number of members . 9 18 15 6 11 15 38 6 14 15 41 16 40 12 20 17 44 The whole number of papers presented to the Society, including those addressed to ordinary and special meetings and to the Mathe- matical Section, has been 786, and they have been communicated by 184 persons. Fifty-seven guests and correspondents of the So- ciety have furnished 67 papers, and 127 members have furnished 719. The total number of persons who have at various times been elected to the Society is 312, and two-fifths of these have contributed something more than remarks to the proceedings. The following numerical data concerning the membership and common membership of the Philosophical and three other scientific societies were derived from what is known as the " Consolidated List of the Philosophical Society," a list containing the names of the active members of the four societies and the resident members of the Cosmos Club. The list had been corrected to December 1, 1887. In Table V the Anthropological, Biological, Chemical, and Philo- sophical Societies are indicated by the initial letters of their names. GENERAL MEETINGS. Table V. Common Membership of Four Societies. 37 Members of one only. A. ._. B C. ... P. ._. 79 101 22 91 293 Members of two only. A.,B.„ 12 A.,C— 1 A., P.- 28 B., C— 2 B., P._. 25 0., P.- 10 78 Members 38 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. M. H. Doolittle read a paper on newton's vis, and was followed by- Mr. B : Pickman Mann, who read a paper ON REFERENCE INDEXING. [Abstract.] The author described in part the systems of indexing the litera- ture of science which he had practised for many years, with illus- trative examples and an argument to show their general applica- bility and value. He commented upon the extent and variety of the literature of science as a whole, and the impossibility of obtaining a knowl- edge of the literature relating to special departments of research without the aid of indices prepared for the purpose. He then dwelt upon the multitude of separate, partial indices now in ex- istence, upon the difficulties experienced in making use of these indices, and the waste of labor expended in disconnected attempts to obviate these difficulties. He adverted to the advantages which would accrue to all students through co-operative effort to obviate the difficulties described, and remarked upon the necessity, in case such co-operation were to take place, of determining upon a system of carrying it out. He considered the advantages which would be gained for temporary purposes by the combination of existing in- dices into one index to be the property of the co-operators and accessible either directly or mediately to all persons interested. He then passed to a consideration of systems by which indices have been constructed hitherto, and those which should obtain in the formation of such an index as was contemplated here. 309th Meeting. December 10, 1887. By courtesy of the trustees of the Columbian University the meeting was held in the law lecture-room of the University building. Invitations to "yourself and friends" to attend the meeting had been mailed to all members of the Anthropological, Biological, and GENERAL MEETINGS. 39 Chemical Societies, and of the Cosmos Club. About one hundred persons were present. Vice-President Mallery presided. President Harkness then presented his annual address, the sub- ject being THE PROGRESS OF SCIENCE AS EXEMPLIFIED IN THE ART OF WEIGHING AND MEASURING. [Printed in full on page xxxvn of this volume.] A vote of thanks for the address was passed by the audience. 310th Meeting. December 21, 1887. the seventeenth annual meeting. The President in the Chair. Thirty-eight members present. The minutes of the 294th, 308th, and 309th meetings were read and approved. The President announced the election to and acceptance of mem- bership of Mr. Joseph William Spencer. The annual report of the Secretaries was read and accepted. [Printed in full on pp. xxxn, xxxiii of this volume.] The annual report of the Treasurer was read and referred to an auditing committee consisting of Messrs. J. S. Billings, J. C. Well- ing, and C. O. Boutelle. [Treasurer's report printed in full on pp. xxxiv, xxxv of this volume.] The Treasurer read the list of members entitled, under Standing Rule 14, to vote at the annual meeting. The constitutional amendment proposed by Mr. Dall at the last annual meeting was adopted by a vote of 26 for to 3 against it. Election of officers was then held. [The result is printed on page xv of this volume.] The rough minutes of the meeting were then read and the Society adjourned. PROCEEDI NGS AT A MEETING COMMEMORATIVE OF THE LIFE AND SCIENTIFIC WORK OF SPENCER FULLERTON BAIRD, HELD JANUARY 11, 1888, UNDER THE JOINT AUSPICES OF THE ANTHROPOLOGICAL, BIOLOGICAL, AND PHILOSOPHICAL SOCIETIES OF WASHINGTON. (41) INTRODUCTION. On August 19, 1887, Spencer Fullerton Baird. Secretary of the Smithsonian Institution, Director of the U. S. National Museum, and U. S. Commissioner of Fish and Fisheries, died at Wood's Holl, Massachusetts, his post of duty in the last named office. His death at once excited throughout the world feelings and expressions of profound regret. At that time nearly all of his Washington asso- ciates in scientific pursuits were absent from the city, on field duty or in vacation, and were thus unable to jointly testify to the affec- tion and respect in which he was held by them. And especially the scientific societies of Washington, none of which meet during the summer months, were unable to immediately take any action in the matter or to give organized expression to the sentiments of their members. With the resumption of meetings, however, it was determined that such expression should be given with all ceremonial complete- ness, and as the senior of the Washington scientific societies, and the one with which Professor Baird had been most closely con- nected, the Philosophical Society took the initial steps in arranging a joint meeting with the Anthropological and Biological Societies, a meeting which might enable the members and their friends to testify not only their profound respect for this foremost scientific leader, but also their affectionate regard for the man. The appended invitation and programme, which was mailed to all members of the Philosophical, Anthropological, Biological, and Chemical Societies, and of the Cosmos Club, sets forth the form taken in those arrangements : (43) 44 PHILOSOPHICAL SOCIETY OF WASHINGTON. Washington, January 4, 1888. Sir: The Philosophical Society in conjunction with the other scientific societies of the city will hold a meeting on Wednesday evening, January the eleventh, in commemoration of the life and services to science of the late Spencer Fullerton Baird, Secretary of the Smithsonian Institution, Director of the National Museum, and United States Commissioner of Fish and Fisheries. Memhers of the societies, and ladies and gentlemen whom they may desire to invite, will assemble in the lecture-room of the Colum- bian University, on the southeast corner of H and Fifteenth streets, at a quarter past eight o'clock. Your presence on this occasion is earnestly desired. C. E. Dutton, Eobert Fletcher, J. H. Kidder, Committee of Management. Opening of the meeting, by the President of the Philosophical Society. Professor Baird as Administrator, Mr. W. B. Taylor, of the Smithsonian Institution. Professor Baird in Science, Mr. W. H. Dall, President of the Bio- logical Society. The Personal Characteristics of Professor Baird, Mr. J. W. Powell, President of the Anthropological Society. Mr. Garrick Mallery, President of the Philosophical Society, called the meeting to order at the time and place above named. RELATIONS BETWEEN PROFESSOR BAIRD AND PARTICIPATING SOCIETIES. By Mr. Garrick Mallert, President of the Philosophical Society. Ladies and Gentlemen : During several winters before 1871, a club, with commingled social and scientific purposes, used to meet in this city at the houses or* its members. A single paper on some scientific subject was read, usually by the host of the evening, following which was a discussion. Supper was always provided. The title of the club only related to the night of meeting, Saturday, and the organization was so loose that several of the survivors among the regular participants at the meetings do not now remember whether they were actual members, or indeed that there was a definite membership. As the city of Washington emerged from the condition of a Southern vil- lage, and the benign policy of the Government increased the num- ber and force of the scientific institutions at the Capital, the need of an organization which should bring scientific men together on an equal footing and give more time to papers and their discussion became manifest. To meet this want the attendants of the Saturday- Night Club, on March loth, 1871, formed the Philosophical Society of Washington, its object, in the words of the call, being "the free exchange of views on scientific subjects and the promotion of scien- tific inquiry among its members." The term "Philosophical," as the first president of the Society, Joseph Henry, stated in his first address, was chosen after consider- able deliberation, "not to denote, as it generally does in the present day, the unbounded field of speculative thought, which embraces the possible as well as the actual of existence, but to be used in its restricted sense to indicate those branches of knowledge that relate to the positive facts and laws of the physical and moral universe." Of the forty-three gentlemen who signed the call twenty-one are now dead. Professor Baird was prominent among the founders, and served continuously as a member of the General Committee from the organization to November 10th, 1877, and from that date until (45) 46 PHILOSOPHICAL SOCIETY OF WASHINGTON. his death, on August 19th last, he was a member of the Committee on Publications. The first communication of a scientific paper to the Society was made by him on March 18th, 1871. The most important and extended original papers communicated by him were "On the decrease of fish on the southern coast of New England," presented March 23d, 1872, and " On the artificial propagation of the cod, describing the measures and process adopted at Gloucester, Mass., and the success thus far obtained," presented March 1st, 1879. The last-mentioned occasion is memorable to me, and some account of it will be interesting to the younger members of the Society, few of whom ever heard Professor Baird's voice raised in its hall. I happened to join him on his way to the meeting, and during the walk he spoke of the struggle at that moment between the sense of duty requiring him to take his part in the proceedings of the Society and his repugnance to making any formal address. This modesty — indeed, timidity—in an eminent writer and thinker, whose lightest words were sure of eager attention in a society composed mainly of his personal friends and wholly of his admirers, was the more remark- able because his address, presented a few minutes later, was most pleasing in its delivery as well as instructive in its substance. He spoke without notes, and, though his style was conversational and in no degree oratorical, his appropriate words in their rapid flow ex- pressed his thoughts clearly, completely, and in orderly sequence. During the same walk, Professor Baird mentioned with earnest commendation the usage of the Society by which the perfect equality of members is recognized through the omission of all official and professional titles. This was not a merely unwritten custom but was founded on a binding resolution, appearing in the minutes of June 6th, 1874. The Society is probably the only non-esoteric body in the United States in which the titles ofJudge and General, Professor and Doctor, Governor, Senator, and even Honorable Member are for- bidden ; the simple and dignified Mr., the modern form of Magister, being the only address allowed. Perhaps the plethora of titles and the burdensome hierarchical gradations in Washington compelled this measure of relief. The Anthropological Society was founded February 17th, 1879, its defined object being " to encourage the study of the natural history of man, especially with reference to America." Professor Baird warmly approved of the organization of this Society, took constant \ GENERAL MEETINGS. 47 interest in it, and, at the time of his death, was the only honorary member residing in the United States on its rolls. The Biological Society was organized December 3d, 1880, "to en- courage the study of the biological sciences," and Professor Baird was the only honorary member ever elected by it. He did not take an active part in the proceedings of either of the last-mentioned socie- ties but gave them material assistance. Both of them met at first in the Regents' Room of the Smithsonian Institution, placed by him at their disposal, and he provided for the stereotyping and circula- tion of their volumes of Transactions, a benefaction which the Philosophical Society had earlier enjoyed. President Henry, in his address before mentioned, stated that in no other city in the United States was there, in proportion to the number of its inhabitants, so many men actively engaged in pur- suits connected with science as in Washington. In the seven fol- lowing years the number of persons in the city engaged in scien- tific work was nearly doubled, and most of them joined the Philo- sophical Society, so that in the year 1878 it had become recognized as the most efficient scientific body on this continent with a mem- bership confined to a single locality. The criteria of this superiority were not only the large membership and regular attendance of members, but the number, quality, and variety of the papers pre- sented and discussed. This abundance and, as was proved by the later successful establishment of differentiated societies as an over- flow, this superabundance of scientific papers occupied every mo- ment of the meetings, so that the members, as such, had no oppor- tunity to become acquainted with one another or to interchange views, except in the formal discussions following the papers an- nounced in the printed programs. There was no provision for social introduction or intercourse. This appreciated want, the converse of the inadequacy of the Saturday-Night Club, resulted in the foundation of the Cosmos Club, on December 13th, 1878, in the organization of which all the members of the Philosophical Society were invited to join. It is needless to descant upon the unique character of the Cosmos Club in its membership and objects, its vital connection with science, literature, and art, and its imme- diate but enduring success. The remark, however, is pertinent that, in the winter of 1878, an unprecedented agitation, excited by im- pending national legislation, perturbed the scientific circles of the Capital, during which the proposition to form the Club was attacked 48 PHILOSOPHICAL SOCIETY OF WASHINGTON. with virulence as a scheme in the selfish interest of a few individ- uals, and one fraught with raachiavelian political designs ; but when Professor Baird manifested his approval of the plan by accepting the first presidency of the Club after its formal organization, con- fidence in him was so dominant that suspicion was allayed and opposition disappeared. To him profound thanks are due for the timely establishment of the most important institution in the con- joint social and scientific life of Washington. But by his work in the organization of these several societies and of the Cosmos Club, Professor Baird was, as in his other fields of labor, a benefactor and not a participant in the benefits secured to others. He was imbued with the cardinal principle of the Smith- sonian Institution not only to establish and assist all useful agencies for the promotion of the well-being of man, but afterwards, when they had attained to successful operation, to leave them to them- selves and explore new fields of beneficence. It was also his own character, apart from any formulated maxim of the Institution, that he could not rest in the personal enjoyment of accomplished results. He was one of the ceaseless workers, born until " To scorn delights, and live laborious days," " Comes the blind Fury with th' abhorred shears And slits the thin-spun life. But not the praise ! " It is for us now, repressing sorrow, to join in tributes of praise to our benefactor. PROFESSOR BAIRD AS ADMINISTRATOR. By Mr. Wm. B. Taylor, of the Smithsonian Institution. We are met this evening to express in a memorial service our respect for an honored fellow-member of our several societies, lately- deceased, and to indulge as well in an interchange of affectionate reminiscence of a departed friend. • Spencer Fullerton Baird was born at Reading, Pa., February 3, 1823. He was graduated at Dickinson College, in Carlisle, Pa., in 1840, at the age of seventeen, and with an original fondness for natural history and the study of the out-door world he spent several years in his favorite pursuits and in collecting animal specimens for preservation. In 1845, at the youthful age of twenty-two, he was elected Professor of Natural History in his alma mater—Dick- inson College. Three years later, in 1848, while still pursuing with ardor the study of nature, he applied for and obtained from the Smithsonian Institution (then recently established) its first modest grant for the promotion of original research. This was to be applied to the ex- ploration of bone caves, and to the development of the local natural history of southeastern Pennsylvania. The transaction appears to have been the occasion of first bringing the young professor to the favorable notice of the Smithsonian Director, Professor Henry, and of initiating between the two a mutual respect and friendship that continued throughout their several lives. The early history of the Smithsonian Institution was signalized by a long struggle—both in the Board of its Regents and in the Halls of Congress—between the votaries of literature and those of science for the disposal of the Smithson fund. During this period, in 1850, when it was seen that the income of this institution was not to be absorbed in the building up of a great National Library, Professor Henry asked of the Regents authority to appoint an As- sistant Secretary in the department of natural history to take charge of the Museum and to aid in the publications and other in- terests of the establishment. A resolution authorizing such an appointment being adopted, Henry selected Professor Baird, of 50 (49) 50 PHILOSOPHICAL SOCIETY OF WASHINGTON. Dickinson College, as the one well fitted for the place. The ap- pointment was unanimously confirmed by the Board July 5, 1850, and Professor Baird being notified at once accepted and entered upon his new duties. He deposited in the Museum his own valu- able collections, comprising an extensive series of the skins of various mammals (European as well as American), a large number of bird skins (unmounted), representing about 500 American species and half as many European species, a rich variety of birds' nests and birds' eggs, more than 500 glass jars, tin vessels, and kegs con- taining alcoholic specimens of reptiles and fishes, and a number of vertebrate skeletons and of fossil remains. The new Assistant Secretary was truly in his element, and showed himself pre-eminently "the right man in the right place." In Henry's Fourth Annual Report (that for 1850), after recording the appointment of his Assistant, he adds : " He entered on his duties in July last and, besides being actively engaged in organizing the department of natural history, he has rendered important service in conducting our foreign exchanges and attending to the business of the press." The Smithsonian system of exchanges was instituted for the pur- pose offacilitating the reciprocal transmission between the Old World and the New of the memoirs of learned societies, and this system has become an essential agency in the interchange and diffusion of knowledge, and in the more rapid advancement of scientific dis- covery, by a wider and prompter co-operation. Previous to this inauguration such distant scientific information was so rarely and inconveniently accessible, largely through the delays and harass- ments of customs exactions, that important principles had not un- frequently been re-discovered abroad or at home, and sometimes with a considerable interval of time, to subsequently disturb and dispute a coveted and settled priority. By the urgent zeal of the Smithsonian Director, representing to foreign powers that only gratuitous distribution of the literary and scientific memoirs of societies or of individuals (not usually found on sale) was undertaken by the Institution, and that no commercial enterprise calculated in any way to interfere with the legitimate operations of trade was attempted—one port after another was opened to its packages, until, in the course of a few years, the an- nouncement was made that the Smithsonian exchanges were allowed GENERAL MEETINGS. 51 to pass through every custom-house on earth, unopened and un- questioned. Creditable as this special liberality is, it has not yet, unfortunately, been applied to the customary channels of book lore, and the quest for knowledge is still held by a majority of civilized nations as an indulgence very proper to be taxed. Our own legislators have also made our higher education a source of revenue; possibly with a view to the "incidental protection" of American science by the heavy tariff laid on the foreign and imported article. The advantage to the cause of science from this Smithsonian sys- tem of international exchange of intellectual products, free of duty, and with the freight expenses assumed by the Institution, can scarcely be too highly appreciated. In the early promotion of this benefi- cent scheme, Professor Baird became an energetic agent and sympa- thetic co-adjutor of the Smithsonian Secretary. The remarkable development of this service may be sufficiently indicated by a glance at the amount of material transmitted through this Institution, on each tenth year for thirty years, showing something like a geometrical ratio of increase. The total weight of books, pamphlets, and charts distributed in 1855 was about six tons; in 1865, about nine tons; in 1875, about twenty tons ; and in 1885, about eighty-five tons. With the rapid growth of the exchange operations, the active and compre- hensive faculties of Professor Baird seemed but to find a better field of exercise. At the same time, the accumulating collections of the museum — increased in 1858 by the transfer from the Patent Office to the Smith- sonian building of the interesting contributions from the earlier national exploring expeditions—demanded a large share of attention for their proper arrangement, exposition, and superintendence.* To say that this important work of organization was zealously and judiciously carried out, is to characterize but imperfectly the di- rective skill and energy of the museum curator. Of Professor Baird's work in original biologic research,—of his contributions to various scientific journals and society proceedings, of his English translation of the popular " Iconographic Encyclo- *This accession of the Government deposit of ethnological and natural history specimens was estimated by Professor Baird, in his report for 1858, as comprising not more than a fourth of the material already in the Smith- sonian Museum or a fifth of the aggregate amount. 52 PHILOSOPHICAL SOCIETY OF WASHINGTON. psedia," of his editorship of the "Annual Record of Science and In- dustry " for eight years,—and of his other publications,—it is not proposed here to speak. This aspect of his intellectual life will be discussed by one in every respect far more competent to a just and discriminating presentation of the theme. The present remarks will be confined to a cursory review of Professor Baird's varied admin- istrative work. For a number of years a notable decline in the productiveness of our extended fisheries had been with anxiety observed, the annual yield of this important element of our food supply having in many cases fallen off one-half of its amount a quarter of a century earlier. So serious a diminution and consequent enhancement of cost of sub- sistence was becoming a menacing problem. Were our leading food-fishes undergoing a process of slow but certain extinction? Several of the States (especially those of New England) appointed commissions of inquiry into the causes and remedies of the threaten- ing evil, but with little result. In the stern competitive struggle that from the dawn of terres- trial palseontogeny has been ordained by nature as the feudal tenure of all existence, and from which service man himself is not ex- empted, the feebleness of early youth in the individuals of every race would speedily terminate the biology of our planet were not provisions made for bridging over these cross lines of weakness to preserve the continuity of species. In the lower classes of being we find the crude expedient of a fertility so enormous as to allow of the wholesale destruction of the unprotected eggs or of their brood, and yet leave a remnant to spare for the chances of reaching adult age. In numerous other classes, a marvellous sagacity is dis- played by the mother in depositing her eggs where they will be least exposed to accident or voracious attack, and where the progeny (that she shall never see) will meet with their appropriate sustenance. In insects this peculiar instinct—so difficult of explanation as " in- herited experience"—is perhaps most strikingly displayed. And lastly, when we ascend to the higher classes of birds and mammals, we find the parental sentiment developed to an untiring vigilance for the protection ,and provident care for the nutrition, of the new generation until it is able to take up for itself the battle of life. As an illustration of the reckless prodigality of productiveness in some of the lower families of the vertebrate branch it may be recalled that a single salmon will lay five thousand eggs; a trout, fifteen thou- GENERAL MEETINGS. 53 sand eggs ; a perch, a herring, or a shad, thirty thousand eggs ; a pike, one hundred thousand eggs; a carp, four hundred thousand eggs; a mackerel, five hundred thousand eggs; a flounder, one million eggs; a haddock, one million and a half of eggs; a halibut, two and a half millions of eggs ; a pollock, four million eggs ; a cod- fish of medium size, five million eggs ; a large-sized cod, nine million eggs, and a turbot, nine million eggs. Such numbers are simply- astounding ; they cannot be realized. Aud how great the marvel when we consider that each of these nine million units is a potential fish, capable of development into all the perfected attributes and functions of the parent form ! Among the lower invertebrates may be simply instanced the oyster—capable of producing the incredible number of twenty or thirty million eggs, and if of large size as many as forty or fifty million eggs. If with this amazing fertility the various kinds offish just named are not rapidly increasing, but are stationary or even decreasing in numbers, how overwhelming must be their early destruction. Even after allowing for the many millions of adult fish taken by man it is obvious that of many species not one in a thousand or in ten thou- sand of eggs or of the newly hatched can survive to maturity. Pro- fessor Mobius estimates that for every grown oyster upon the beds of Schleswig-Holstein more than a million have died. To avert, if possible, the menace of increasing scarcity of fish supply the attention of Congress was directed, to the subject;—the more properly since in our National Government resided the juris- diction over our extended sea coasts. By a joint resolution, approved February 9, 1871, the President was authorized and required to appoint a person of proved scientific and practical acquaintance with the fishes of the coast to be Commissioner of Fishes and Fisheries, with the duty to prosecute investigations into the causes of diminu- tion, if any, in numbers of the food-fishes of the coast and the lakes of the United States, and to report whether any and what protective, prohibitory, or precautionary measures should be adopted in the premises. No man more suitable for this important and responsible position than Professor Baird could have been selected. He was at once appointed by President Grant and confirmed by the Senate as the Commissioner. In his first report he announced, as the result of a most careful and thorough examination, that the decrease of the shore fishes of the New England waters during the preceding twenty 54 PHILOSOPHICAL SOCIETY OF WASHINGTON. years was fully substantiated, and that it had been much more rapid since the year 1865. In furtherance of his great work, the resources of the Smithsonian Institution were freely placed at the disposal of the Commissioner; and, in the same report, he gratefully acknowledges this hearty co- operation by saying : " I am indebted to Professor Henry for per- mission to use the extensive collection of apparatus belonging to the Smithsonian Institution, in the way of nets, dredges, tanks, &c, and thus saving the considerable outlay which would otherwise have been necessary." The new studies into the life-history of the principal shore fishes,—into the character and range of their enemies, and into their appropriate means of subsistence, requisite to an intelligent consideration of the conditions most favorable to their propaga- tion,—involved investigations embracing the entire marine fauna of the coast, vertebrate and invertebrate. These extensive and varied researches necessarily demanded the aid of skilled assist- ants—of a corps of eminent specialists in marine biology, and a corresponding division of labor. The results of these investigations have been given to the world in hundreds of memoirs, published in the Reports and Bulletins of the Commission, and in the Proceedings and Bulletins of the National Museum. And it is quite within bounds to say that in importance, in variety, and in extent of original information thus communicated, no such quantity of contribution to our knowledge of zoology has ever emanated from any other organization within the same in- terval of time. Many species of fishes entirely new to science have been discovered and carefully described ; and the number of in- vertebrate forms known to inhabit the waters explored, has prob- ably been fully doubled. It was found, from the abundance of the lower forms of life, that the decline of the useful fishes had not resulted from any lack of their accustomed food-supply; nor had it resulted apparently from any less favorable conditions of environment, nor from the preva- lence of any epidemic diseases. It was therefore a consequence of excess in their destruction. Among all the ravages of predaceous fishes it was found that the "bluefish" was the most voracious and devastating pirate of the coast. In the report it is stated: "Sometimes among a school of herring or menhaden thousands of bluefish will be seen biting off GENERAL MEETINGS. 55 the tail of one and then another, destroying ten times as many fish as they really need for food, and leaving in their track the surface of the water covered with the blood and fragments of the mangled fish." Fortunately this fish is itself valuable for food, and it is ac- cordingly taken in large numbers.* But by far the most rapacious and destructive scourge of the waters is man himself. By reckless extravagance in his methods of capture he would soon consume the capital of his abundant patri- mony were no restraints imposed upon the thoughtless improvidence of his greed. With the growth of population and demand and the improved facilities for rapid transportation, the stimulus to inventive ingenuity occasioned the establishing of fish-traps and fish-pounds on a large scale that gathered thousands in their confines, with little regard to the probable supply of the future. As these traps and pounds were placed directly in the way of the fish to their spawn- ing beds, it resulted that a very large proportion of spawn fishes were taken by them, thus greatly reducing the prospects of the suc- ceeding generation. Whatever protective measures might be deemed expedient to check this spendthrift waste, it was seen that the most immediate and' promising work of the Commissioner would be to promote the rapid multiplication of fish ; and to this dominant interest the an- nual appropriations by Congress have been more and more largely directed. Pisciculture is by no means a recent art, it having been exten- sively practiced by the Chinese for a number of centuries; and even the artificial fecundation of fish-spawn is nearly a century and a third old, having been apparently first introduced by Jacobi, a German, of Westphalia. Most of the European nations had already given attention to the practical application of fish-culture, and in different parts of our own country enterprising individuals had un- dertaken the operation with gratifying results. Under the organizing direction of Professor Baird a careful study was made of existing methods, extended experiments on artificial propagation were conducted, and successive improvements in the various stages of incubation, hatching, and development intro- *In his first report, Professor Baird says: "I am myself cognizant of the capture of no less than 20,000 bluefish, representing a weight of at least one hundred thousand pounds, in one weir in the course of a single night." 56 PHILOSOPHICAL SOCIETY OF WASHINGTON. duced,—each detail receiving a scientific treatment,—until a scale of success has been effected far more complete and "satisfactory than ever before attained. While under natural conditions but a small proportion of the spawn deposited is hatched (the greater mass being eagerly devoured by various aquatic tribes), and of the por- tion hatched but a small percentage escapes to reach maturity, under the careful breeding of art fully ninety per cent, of all the eggs secured are fertilized and successfully developed. Of the practical results of this great national enterprise it is un- necessary to speak. A dozen varieties of our best food-fishes have been disseminated throughout the inland waters and the seaboard of our country in increasing quantities ; transported in the form of the young fry, or in that of fertilized eggs to other hatching stations ; and while an accurate estimate is, perhaps, at present not easily attainable, it will hardly be held an exaggeration to say that these productions are to be numbered by thousands of millions. Of these, many millions (by a most praiseworthy public courtesy) have been distributed to foreign countries—to Australia, to Brazil, to Canada, to England, to France, to Germany, to Mexico, to The Netherlands, to Scotland, and to Switzerland. In the great International Fisheries Exhibition at Berlin in 1880 our national commission was authorized by Congress to participate. Professor Baird appointed as his deputy to personally superintend this movement Professor Goode, the present Fish Commissioner, under whose energetic direction, in a remarkably short space of time, the marvellous American exhibit was organized, transported, and installed, to the wonder and admiration of every visitor. The head of the American Commission was hailed by the President of the German Fisheries Association as the " chief fish-culturist in the world," and to him was awarded for the most complete and impos- ing display of all the details and accessories of his scientific art the unique first-honor prize of the exhibition, the gift of the Emperor of Germany. But time fails to permit more than a passing glance at other fields of activity no less important in which Professor Baird employed his remarkable powers of executive management. The Smithsonian Institution from its inception had given great encouragement to explorations, and its director had zealously labored to enlist, as far as practicable, the various expeditions undertaken by the Govern- ment, in the extension of scientific research. These efforts were lib- GENERAL MEETINGS. 57 erally responded to by the Executive Departments, and trained ex- perimentalists and observers were given every facility for physical, physiographical, and biological investigations at distant points. The Institution thus became almost the Government superintendent of scientific expeditions. In all that pertained to ethnology and natural history Professor Baird became of course the leading spirit, and the various circulars of direction and of inquiry issued by him show with what range and thoroughness he supervised this wide department, while the resulting memoirs and valuable museum accessions attest as their fruits the practical wisdom of the measures and methods adopted. Congress having made provision for the representation by the Government in the National Centennial Exhibition to be held at Philadelphia, the President of the United States requested the Ex- ecutive Departments, together with the Smithsonian Institution, to co-operate in a collection illustrative of our progress and resources. In his report for 1875, Professor Baird formulated (as requested by Professor Henry) his plans for the different details of the projected exhibit, and, these being adopted, were carried out to a result that made the Smithsonian display the leading attraction of the exten- sive Government building. At the death of Professor Henry, in 1878, his faithful assistant and coadjutor was elected by the Regents as his successor, and his long familiarity with the different lines of active operations pursued by the Institution made him from the start an efficient director. Another grave responsibility was thus thrown entirely upon his shoulders, and he proved himself equal to the occasion. In 1879, Congress made an appropriation (since continued an- nually) for the prosecution of North American ethnology, to be expended under the direction of the Smithsonian Institution. For the administration of this important trust, Professor Baird selected one whom he knew to be peculiarly fitted by training, by zeal, and by congenial tastes, to pursue successfully the anthropologic study of our waning aborigines, and the new Bureau of Ethnology was judiciously committed to the control of the distinguished director of the Geological Survey, Major Powell. In the same year (that following Henry's death) an appropria- tion (for many years importunately besought of Congress) was made for the erection of a national museum building. In 1882 the com- pletion of this building rendered necessary the re-organization of the 58 PHILOSOPHICAL SOCIETY OF WASHINGTON. Museum, with a staff of expert, curators, on a scale commensurate with its importance, and the abundance of its previously stored ma- terial. Professor Baird hail now become the manager of three great establishments -the Fisheries Commission, the Smithsonian Insti- tution, and the National iMiiseuin ; either one of which was a charge siillieient to fully task the energies of a vigorous man. No wonder, with the strain of unremitted though divided attention to these exacting duties, thai, while unconscious himself of any unaccustomed or undue exertions, he should find even his robust and stalwart, Strength was slowly failing under his accumulated labors. Informed by his medical adviser that an entire and continued rest from nil intellectual exertion was necessary to restore his nervous energies to their wonted tone, he reluctantly accepted the decision. A year ago he asked from the Smithsonian Regents authority to a p- point two official assistants to relieve him from the greater portion of his responsibility, and in hearty compliance with his expressed desire, the eminent astronomer and physicist, Professor Langley, was appointed assistant in charge of the Smithsonian operations, and his well-tried friend and collaborator, Professor Goode, was ap- pointed assistant, in charge of the Museum aifairs. Put the relaxation came too late. After a vigorous resistance of his strong constitution to the encroachments of internal organic derangements, he finally succumbed to the Destroyer, and quietly breathed his last, on the 1 9th of August, 1887 ;—another example (far more frequent, in the higher than in the lower fields of occupa- tion) of sacrifice to over-work. Prom even this hurried and imperfect sketch of Professor Hand's diversified administrative work it is at once apparent that he pos- sessed, in a pre-eminent degree, two great capacities,—the faculty for successful organization, and the faculty for continuous labor. As a, biologist he had made a study of the entire range of organic nature—vegetable and animal ; and with the accuracy of the special- ist, he combined the larger and fuller perception of the genera] zoolo- gist, as to the functional and genetic inter-relations of animated being, The tenor Of his mind was rather Synthetic than analytic. While he ever displayed a marvellous memory for particulars and a com- prehensive grasp of details, these were apprehended more as the constituents of a general end or purpose, than as the residuals of a, disjunctive Conception. Clear-sighted and determined, he prevised GENERAL MEETINGS. 59 and compassed the result in the means. Simple and unostentatious, he received with ready affability a visitor, even when most pre-occu- pied. What young naturalist ever applied to him for the resolution of a difficulty or uncertainty without receiving cordial attention and satisfactory enlightenment ? Great as were his undoubted services in the original discovery of biologic truths, it may well be doubted whether his indirect influ- ence in the advancement of science was not still greater, by the assistance and encouragement given to others and by his numerous official occasions of directing the efforts of the aspiring into channels of novel exploration whenever the opportunities of land or naval expeditions presented themselves. Now that the first shock of bereavement at missing one who has occupied a prominent place in the public eye, as well as in our private regard, has somewhat subsided, we but the more clearly realize that in the lamented death of Spencer F. Baird the scientific world has lost an accomplished and illustrious naturalist, the insti- tutions over which he presided an energetic and judicious admin- istrator, and we, assembled here, an exalted associate, a faithful counsellor, an ever open-hearted friend. PROFESSOR BAIRD IN SCIENCE. By Mr. Wm. H. Dall, President of the Biological Society. In accepting the honor of addressing you this evening on the bio- logical work of Prof. Spencer F. Baird it is hardly necessary to state that I have felt keenly the inadequacy of my own equipment for the task. Not only does it happen that my own work has been almost entirely in departments of biology different from those which he adorned, but my early efforts were fostered by his wisdom and geniality, the period of my scientific studies has coincided with an acquaintance which ripened into affection and admiration, they have depended for their results upon opportunities largely due to the intervention of Professor Baird, and I feel that the best and truest of him is that which cannot be put in words. The sense of personal loss, as with many of you, is still so keen as to accentuate the difficulty of doing justice to the theme assigned me. I should have almost despaired of myself on this occasion were it not that others have aided me in my endeavor to set forth the debt owed by the various departments of research to Professor Baird's original investigations. To naturalists so distinguished in their specialities as Ridgway, Stejneger, Goode, Coues, Allen, Merriam, and Yarrow, I am indebted either for direct contributions toward the substance of this address or for matter in their published works Avhich has been similarly utilized. Professor Baird's scientific activity was exhibited in three prin- cipal directions: First, in original investigation of the zoology of vertebrates; second, in the diffusion of scientific knowledge and methods through official documents, reports, cyclopedias, and records of progress; and lastly, in the organization and administration of scientific agencies such as the National Museum or the Fish Com- mission, which include in their scope not merely public education or economic applications of science, but the promotion of research. Behind all these and hardly less important for science was the per- sonal influence of the man himself, which shone through all the planes of his activity as coruscations light the facets of a gem. (61) 62 PHILOSOPHICAL SOCIETY OF WASHINGTON. Although it is very difficult to separate the phases of his work, one from another, so closely were they inter-related, my theme to- night is restricted to the impress left upon zoological science by Baird's original investigations. So great has been his reputation as an organizer, so numerous have been the publications in which he has garnered for the public the precious grain of the annual scien- tific harvest, that the extent and importauce of his original work, except by specialists, is in danger of being overlooked. We owe an excellent bibliography of his publications to Professor Goode. From this we learn that, up to the end of 1882, the list comprises nearly eleven hundred titles, from which, after deduction of all notices, reviews, official reports, and works edited for others, some two hundred formal contributions to scientific literature re- main, many of which are works of monographic character and ex- tensive scope. "With the exception of a single early botanical paper these relate to the vertebrates of America and, in their several branches, cover nearly the entire field. Although descriptions of species in them- selves afford a poor criterion of the value of the work containing them, it is interesting to note that, among the terrestrial vertebrates, the proportion of the fauna first made known by Baird to the total number recognized at the time as North American varied from twenty-two per cent, of the whole to forty per cent, in different groups. His method of study of new material was as far removed as possi- ble from bookishness. In the case of the collections from Hudson Bay or the Pacific Railroad Surveys, when birds, mammals, or rep- tiles sometimes came to hand by hundreds, each specimen having the collector's data attached, the whole collection was thrown to- gether, each form to be sorted out on its merits and studied in the light of a multitude of specimens. Professor Baird's early life had iucluded so much of exercise in the shape of long pedestrian journeys with gun aud gamebag, so much familiarity with the wood-life of his favorite birds aud mam- mals, that it would have been in any case impossible to class him with the closet-naturalist, while to this knowledge he added a genius for thorough, patient, and exhaustive research into all which con- cerned the subject of his study, and a wonderful inventiveness in labor-saving devices for labelling, museum work, and registration. GENERAL MEETINGS. 63 He had a wonderful capacity for work. He undertook and car- ried out successfully tasks which it would seem nobody else would have dared to attempt, or, attempting, would have been physically unable to complete. In the case of the immense volume on the mammals of the Pacific Railroad Surveys he says in the preface, July 20, 1857 : " The examination of the material was actually commenced early in 1855 and many of the articles written in that year or 1856. With the continual accession of additional specimens it became finally necessary to rewrite, alter, or extend all that had been pre- pared prior to the present year (1857). It is to this that the fre- quent want of uniformity is due, the time allowed not being suffi- cient in many cases to permit the reworking of the whole matter. * * * It is, perhaps, unnecessary to state that the matter of the present report is entirely original throughout. * * * It is proper to state that, owing to various circumstances, the work was necessarily passed through the press with a rapidity probably un- exampled in the history of natural-history printing, allowing very little opportunity for that critical and leisurely examination so necessary in correcting a work of the kind. For most of the time the proof has been furnished and read at the rate of twenty-four to thirty-two pages per day, nearly 400 pages having been set up, read, and printed during the first half of July alone. Owing to the urgent necessity for the speedy completion of the volume, no time was allowed for the revision of the manuscript as a complete work, nor, indeed, of its separate portions, and, for much of the time, the preparation of much of the manuscript was only a few hours iu advance of its delivery to the compositor." The volume above referred to contains over 800 quarto pages and 42 plates. The manuscript was entirely prepared after six o'clock of working days which had been spent in the active admin- istrative and executive work of the Assistant Secretary of the Smithsonian Institution, then unassisted by stenographer or other clerical supplement. Fortunately for science Baird did not always have to work under such circumstances, but the incident shows what he was capable of doing when the occasion seemed to him to warrant it. Probably no other work of equal importance, on any subject, was ever carried out under such pressure. Mammals.—Professor Baird's contributions to a knowledge of North American Mammals, though less voluminous than those re- lating to birds, are not less important. Previous to this time but 64 PHILOSOPHICAL SOCIETY OF WASHINGTON. one general work on the subject had been published, that of Audu- bon and Bachman on the Quadrupeds of North* America, which was issued in three volumes, from 1846 to 1854* Immediately after the completion of this great work collections began to pour into the Smithsonian Institution from the various exploring parties of the Pacific Railway Surveys. This material comprised so large a number of new species, and cast so much light upon many pre- viously doubtful points concerning the relations of species already described, that a revision of the whole subject became necessary. Hence Professor Baird at once set about the preparation of the book commonly known as the Mammals of North America. I have already alluded to the manner in which it was prepared. This great work was rapidly pushed to completion and appeared in 1857, just three years after the publication of the last volume of Audubon and Bachman's Quadrupeds. It constitutes the eighth volume of the Pacific Railroad Reports, and is a ponderous quarto of more than 800 pages, accompanied by numerous excellent plates. Though published thirty years ago, this work still remains the standard general treatise on North American mammals. It con- tains no biographical matter, but consists wholly of technical de- scriptions. It treats of all the mammals then known from the continent of North America north of Mexico, except the bats and the truly pelagic forms—whales, sea cows, and seals. The total number of known species was increased nearly twenty-five per cent. In fullness of synonymy, and in the correct assignment of species previously described, Professor Baird was much in advance of pre- vious workers. The descriptions, which are models of painstaking accuracy and precision, are taken from the specimens themselves, and are accompanied by long tables of measurements, the value of which more than justifies the enormous expenditure of time neces- sary in their preparation. Much more attention was paid to crani- ological characters than had been the custom with previous writers, which fact contributes largely to the permanent value of the work. Professor Baird's long training as a careful observer, his power of concentrating his knowledge of matters under investigation, the * The volume on Mammals of Richardson's Fauna Boreali Americana does not fall under this head, because it treats only of the northern portion of the continent. GENERAL MEETINGS. 65 wide scope of his information on nearly all departments of natural science, his clear perception of details, together with his excellent judgment, which was as marked in matters of minor detail as in those requiring great executive ability, enabled him to draw con- clusions which subsequent accumulations of material have verified in a surprising manner ; in fact, his pre-eminent superiority as a systematic zoologist is everywhere apparent. Birds.—When the great interest he took in birds is considered, and the long period over which his studies extended, it is somewhat surprising to find that the number of separate papers on ornithology published by Professor Baird sums up only some seventy-nine titles. It is less to their number that he owed his fame as an ornithologist than to their quality, combined with the fact that several of these publications covered practically the entire field of North American ornithology, and were of the nature of monographs. " His reputation was, indeed, established," says Ridgway, " by the first of his separate works, usually known and quoted as the " Birds of North America," though not published under this title until two years after it had been printed by the Government as Volume IX of the Pacific Railroad Reports. With the publication of this great quarto volume, containing more than a thousand pages, in 1868, began what has been fitly termed by Dr. Elliott Coues the " Bairdian period " of American ornithology. This period, cover- ing almost thirty years, was characterized by an activity in ornitho- logical research and a rapidity of advancement without a parallel in the history of the science. Of the "Birds of North America" Coues states* that "it repre- sents the most important single step ever taken in the progress of American ornithology in all that relates to the technicalities." The nomenclature was entirely remodeled from that previously in cur- rent use, and for the first time was brought abreast of the systematic acquirements of the time. The synonymy of the work, in which is embodied the history of investigation relating to each species, is more extensive, reliable, and elaborate than any before presented. With few exceptions, citations were original, and when, as occasion- ally happened, they were necessarily at second-hand the fact was *Bibl. app. to the Birds of the Colorado Valley, p. 650. 51 66 PHILOSOPHICAL SOCIETY OF WASHINGTON. always indicated. The text comprised not only diagnoses and de- scriptions of each species, but extended and elaborate commentary, comparisons and criticisms. In this learned and sagacious work Professor Baird was aided by Cassin and Lawrence, two of the leading ornithologists of America. It exerted an influence perhaps stronger and more widely felt than any of its predecessors, Audubon and Wilson not excepted, and marked an epoch in the history of American ornithology. The data original to and embodied in this work have been used again and again by subsequent writers with various modifications. Such a monument of original research is likely to remain for an indefinite period a source of inspiration to other writers, while its authority as a work of reference will always endure. The publication of this work rendered possible the studies and progress of a large number of persons, who without it would hardly have been able to enter the domain of scientific ornithology, but who, aided by the book as a standard of reference and by the genial correspondence and pregnant suggestions of its author, have made reputations of more or less distinction for valuable and permanent original investigation. The number of those who profited by this stimulation has been very large and in this way arose what has been called* the Bairdian School of Ornithologists, a school char- acterized by exactitude in matters of fact, conciseness in deductive statement, and careful analysis of the subject in all its various bearings. Its work is marked by a careful separation of the data from the conclusions derived from them, so that conclusions or arguments can be traced back to their sources and duly weighed, while the writings of the older European school afford little basis for analysis. In substance, according to Dr. Stejneger, the Euro- pean method required an investigator to accept an author's state- ments and conclusions on his personal responsibility alone, while the method originated by Baird furnishes him with tangible facts from which to make his deductions. These distinctive features were still further developed by the publication in 1864-'66 of the "Review of American Birds," a work of unequalled merit, displaying in their perfection Professor Baird's wonderful powers of analysis and synthesis, so strongly combined in his treatment of difficult problems. Although never * Stejneger, Proc. U. S. Nat. Mus., VII, 1884, p. 76. GENERAL MEETINGS. 67 completed, this work has received unstinted praise from all compe- tent to estimate it. It is said on excellent authority that no other single work on American birds has made so profound an impression on foreign ornithologists, notwithstanding the fact that circum- stances prevented it from being made complete. Although in his systematic work Professor Baird, like other naturalists, built partly on the scientific foundations laid by his predecessors and contemporaries, always with due acknowledge- ment, the high value of his work in this direction was largely due to an unerring instinct which enabled him to recognize and confirm the best features of the work of others and by adding ma- terial from his own lines of original research to combine the whole into a fabric which was a distinct advance on anything previously offered to the scientific world. While the bent of his genius led him, in this as in other depart- ments, to devote a main proportion of his work to the systematic biology which was the need of the time, and which, with the explora- tion and description upon which it is based, must always precede and lay the track for the theoretical biology more in vogue to-day, it must not be supposed that the work of Baird was confined to de- scriptive and systematic work. With the latter in his publications are combined a host of biographical data such as the field naturalist revels in. One of the earliest and most pregnant papers bearing on mutations of specific forms which have been contributed to the literature of evolution by American biologists is to be found in his article on the " Distribution and Migrations of North American Birds" published in the American Journal of Science in 1866.* In this paper, an abstract of a memoir presented to the National Academy of Sciences in 1865, are to be found the germs of much of the admirable work which has since been elaborated by other biologists on the correlation of geographical distribution and the peculiarities of the environment, with the modifications of color, size, and structure in the forms of animal life, called species. Unlike some of his contemporaries twenty years ago, the views of Darwin excited in him no reaction of mind against the hypotheses then novel and revolutionary. His friendly reception of the new theories was so quiet and undisturbed that, to a novice seeking his *Am. Jour. Sci. and Arts, 2nd Series, XII, pp. 78-90, 184-92, 337-47, 1866. 68 PHILOSOPHICAL SOCIETY OF WASHINGTON. inal. How well this work was done is shown by the fact that, in spite of the changes which are constant in zoological classification, nearly all the species still retain the names he applied to them. The descriptions were so carefully prepared that later students have never beeu troubled in making their identifications. Notwithstanding his multifarious duties in later years, Professor Baird never lost his interest in these animals, and up to the last afforded every aid and encouragement to those studying them. Much of the work done in this country by such herpetologists as Girard, Kennicott, Hallowell, Cope, and others, found in his ex- ample and encouragement the stimulus which made it possible, was built on the foundations which he laid, and owes its publication to agencies which he promoted or controlled. Fishes.—Professor Baird's contributions to ichthyological liter- ature number some fourteen or fifteen papers, chiefly of a descriptive character, embodying the results of original research into the ichthy- ology of western and southwestern America and of the marine fishes of New Jersey and New York. Most of these papers were published jointly with Charles Girard. Besides these, however, he added more than four hundred titles to the list of reviews, notices, reports, translations, and official docu- ments relating to economic ichthyology, fish culture, and the gen- eral progress of the science. In this way he was instrumental in bringing together for the use and benefit of the English-speaking public the largest body of facts relating to fish and fisheries ever prepared and digested for such purposes by any individual or organization. Recognized by experts of foreign countries with one accord, as the most eminent living authority on economic ichthy- ology, America owes to his fostering care and unwearied labor the existence of a whole generation of ichthyologists, breeders of fishes, and inventors of appliances of all sorts for use in connection with the taking, preservation, and increase of these animals. So thoroughly is this understood by all who are in any way acquainted with American fish and fisheries, that to them this statement will appear a truism. It does not enter into the purpose of this address to enumerate the economic results of the Commission which grew into such stately proportions under his skillful and progressive leadership, nor yet to enumerate the multitudinous researches in pure as well as eco- GENERAL MEETINGS. 69 advice and opinion amid the clatter of contending voices, it seemed almost as if the main features of the scientific gospel of the new era had existed in the mind of Baird from the very beginning. His thorough apprenticeship in the study of details of structure and their expression in systematic classification, as well as his cautious and judicial habit of mind, prevented him, notwithstanding his hearty recognition of evolutionary processes, from falling into those exuber- ancies of utterance and hypothesis characteristic of narrowness and immaturity which, within the memory of most of us, have enjoyed a sort of vogue now happily on the decline. Batrachians and Serpents.—Professor Baird's contributions to herpetology began as early as 1849, his first paper being a revision of the North American tailed batrachians which appeared in the Journal of the Academy of Natural Sciences of Philadelphia. Ex- cluding notices of the work of others in the Annual Record between 1849 and 1880, he published fourteen papers on this branch of science beside nine of which he was the joint author with Charles Girard. His activity in original work in this, as in some other directions, came to an end with the assumption of the burden of administrative work required by the organization and development of the Fish Commission. Many of his herpetological papers were elaborate studies. One of the most important of the early memoirs was that on the reptiles of Stansbury's expedition to the valley of the Great Salt Lake, and another, that on those collected by the United States exploring ex- pedition under Wilkes. The catalogue of North American Reptiles in the collection of the Smithsonian Institution is a classical work, serving to the present day as a text-book for students of herpetology. In 1859 appeared his great study of the reptiles collected by the parties engaged in the explorations for a Pacific railroad, a monu- ment of patient research and discriminating analysis. After this his contributions to the subject were mostly short papers or an» nouncements of new or interesting facts. At the time Professor Baird began his studies of the amphibia little had been done for herpetology in America. The classical work of Holbrook contained little more than descriptions of Southern species aud the work of Dumeril and Bibron was equally meagre. Immense collections were placed in Baird's hands from the Western plains, and the work upon these was necessarily in great part orig- 70 PHILOSOPHICAL SOCIETY OF WASHINGTON. nomic biology for which this organization has furnished material and means. No more emphatic object-lesson of the vital relations existing between research, as such, and the promotion of the ma- terial interests of mankind has ever been furnished to the so-called " practical man " than that afforded by the work of the United States Fish Commission as directed by Professor Baird. Whether germane to the subject of scientific research or not, the most narrow specialist can hardly grudge an allusion to the grandeur of the methods by which the food supply of a nation was provided, hundreds of rivers stocked with fish, and the very depths of ocean were repopulated. Typically American we may call them in their audacity and their success. The Fishery boards of foreign countries, first quietly indifferent, then loudly incredulous, iu due time became interested iuquirers and enthusiastic folloAvers. In a few years we may fairly expect to see the food supply of the entire civilized world materially increased, with all the benefits which that implies, and this result will in the main be owing to the unremunerated and devoted exertions of Spencer F. Baird. THE PERSONAL CHARACTERISTICS OF PROFESSOR BAIRD. By Mr. J. W. Powell, President of the Anthropological Society. Baird was one of the learned men of the world, and, to a degree perhaps unexampled in history, he was the discoverer of the knowl- edge he possessed. He knew the birds of the air, from the ptarmi- gan that lives among everlasting snows, to the humming-bird that revels among the orchids of the tropics ; he knew the beasts of the forests and the prairies, and the reptiles that crawl through desert sands or slimy marshes ; he knew the fishes that scale mountain torrents, that bask in quiet lakes, or that journey from zone to zone through the deep waters of the sea. In all this realm of nature he had a minute and comprehensive knowledge that no other man has ever acquired. What others have recorded in this field of research he knew, and to their discoveries he made a contribution of his own so bounteous, so stupendous, that he is recognized as the master of systematic zoologists. All of Baird's scientific work is an illustration of modern induc- tive or scientific reasoning. The inductions or general principles of modern science are reached by the accumulation of vast stores of facts. He knew how to accumulate facts ; how to reject the trivial and select the significant. Modern science is almost buried under the debris of observation, the record of facts without meaning, the sands of fact that are ground from the rock of truth by the at- trition of mind; but Baird could walk over the sands and see the diamonds. Then he knew how to marshal significant facts into systems, and to weld them into fundamental principles. In all his works there can be discovered no taint of a priori reasoning or syllogistic logic ; for in his mind there was no room for controversy, and disputation fled before the light of his genius. Formal logic, a disease of modern thought,—the contagion of Arktotleina,—never (71) 72 PHILOSOPHICAL SOCIETY OF WASHINGTON. ravaged his brain. With healthful directness, he sought the truth guided by wise inference, and told the truth in its simplicity. Baird was an organizer of the agencies of research. When a bold explorer essayed to penetrate the seas of ice by the path of peril and in quest of fame, Baird would ever so manage that a corps of quiet scholars should be attached to the expedition to study the climate of the Arctic zone, the geology of the Arctic rocks, the flora of the Arctic lands, or the fauna of the Arctic fields ; and the best knowledge we have of the igloo-dwellers, the Eskimo whose home is on the ice of the North, has been brought to us by the quiet students he succeeded in attaching to Arctic exploring expeditions : and so the love of glory was made to serve the cause of truth. When, in the interests of international commerce, expeditions were sent to explore and survey routes of travel and transportation across Central America from sea to sea, he managed to send with them corps of scientific men whose function it was to bring from the tropics all forms of its abundant life, vegetal and animal, and the relics of the arts of the people of Central America as they are exhibited in stone and clay and gold ; and the National Museum has been enriched by the results of this labor, and the boundaries of human knowledge extended thereby : and so the greed of gain was made to serve the love of truth. When our army was distributed on the frontiers of the land, he everywhere enlisted our scholarly officers into the service of science and he transformed the military post into a station of research, an Indian campaign into a scientific expedition. Scott, Marcy, Mc- Clellan, Thomas, and many other of the great generals of America, were students of natural history and collectors for Baird. When our navy cruised around our shores, its officers were inspired with that love of nature which made every voyage of military duty a voyage of discovery in the realms of natural science; when they journeyed among the islands of the sea they brought back stores of scientific materials, and when they sailed through the littoral waters of other continents they made voyages of scientific investigation. Many of these earlier naturalists of the Navy in subsequent times became commodores and admirals. But time would fail me to tell of the exploring expeditions and the railroad surveys throughout America, and the travels through- out the world, which he utilized in the interest of science, or of which he was the immediate projector. Of the abundant material GENERAL MEETINGS. 73 thus gathered from all parts of the world, some has gone to enrich American institutions of learning, and some has been gathered into the National Museum—the outgrowth of Baird's organizing genius and a splendid monument to his memory. The hills of the land stretch not so far as the billows of the sea ; the heights of the mountains are not so great as the depths of the ocean ; and so the world was unknown until this greater region was explored. The treasures of the land did not satisfy the desires of Baird ; he must also have the treasures of the sea, and so he organ- ized a fish commission, with its great laboratories and vessels of research. " What hid'st thou in thy treasure-caves and cells, Thou hollow-sounding and mysterious main ? Pale, glistening pearls and rainbow-colored shells, Bright things which gleam unreck'd of, and in vain. Keep, keep thy riches, melancholy sea ! We ask not such from thee." What the scholar asked of the sea was all its forms of life, its organisms minute and lowly, its crawling articulates, its pearl- housed mollusks, its fishes that swim in armies, and its leviathans that prowl among the waves—the life of the reedy shore, the life of the ocean-current, and the life of the deep sea. So, with many ingenious appliances, he and his lieutenants sailed away to explore the ocean's mystery. So the Fish Commission was an agency of research ; but it was more ; he made it an agency by which science is applied to the relief of the wants of mankind, by which a cheap, nutritious, health- ful, and luxurious food is to be given to the millions of men. He affirmed that for the production of food an acre of water is more than equal to ten acres of land, thus giving to the gloomy doctrine of Malthus its ultimate refutation, and tearing away the veil of despair from the horizon of the poor ; for, when the sea shall serve man with all the food that can be gathered from its broad expanse, the land cannot contain the millions whom it is thus possible to supply. In the research thus organized the materials for the work of other scientific men were gathered. When a great genius reads to the world a chapter from the book of nature the story is so beau- tiful that many are stimulated to search in the same field for new chapters of the same story. Thus it was that the publication of 74 PHILOSOPHICAL SOCIETY OF "WASHINGTON. Baird's great works on natural history developed in America a great corps of naturalists, many of whom have become illustrious, and the stimulus of his work was felt throughout Europe. In the research which he organized the materials were furnished for this corps of naturalists ; but his agency in the development of this body of Avorkers was even more direct. He incited the men personally to undertake and continuously prosecute their investigations. He enlisted the men himself, he trained them himself, he himself fur- nished them with the materials and instruments of research, and, best of all, was their guide and great exemplar. Thus it was that the three institutions ov%r which he presided—the Smithsonian In- stitution, the National Museum, and the Fish Commission—were woven into one great organization—an university of instruction in the methods of scientific research, including in its scope the entire field of biology and anthropology. Such is Baird the investigator, Baird the organizer, and Baird the instructor in the length, breadth, and thickness of his genius, the solidarity of a great man. All that I have said is a part of the public record ; it is found in the great libraries of the world ; but, however exalted the feeling of admiration we may entertain for Baird as a scholar and admin- istrator, it is to his attributes as a man, as disclosed in his personal relations with friends, associates, and contemporary men of affairs, that we most fondly turn. It is in these relations that he most clearly exhibited those kindly and modest traits of character which made him so universally beloved. As a man of affairs, Professor Baird exhibited great sagacity. His plans for the organization of scientific work were of great mag- nitude, and had they been presented to the administrative officers of the Government or to legislative bodies with exaggeration, or even had they been presented with the glow of an enthusiastic missionary of science, they might well have encountered opposition. But Baird had a wonderful faculty of presenting his plans with extreme modesty, and with a degree of understatement, but sugges- tion of possibilities which speedily caused him to whom the appeal was made himself to become an advocate of the Professor's measure. He had traits of character in this respect which are hard to explain, and which seem at first to be contradictory. In the advocacy of measures his modesty amounted almost to timidity, and he avoided alike argumentation and ostentation, and he presented his measures with the directness of a child. Notwithstanding all this, there was GENERAL MEETINGS. 75 such a poise of faculties—such dignity of mien—that he impressed those with whom he came in contact as a venerable and wise patri- arch. He seemed devoid of personal interest or feeling, and solici- tous only for the welfare of those to whom he was in fact appealing, and he conveyed the impression that he was giving benignant ad- vice. Thus the shrinking, sensitive man, who could not even stand before a public body, such as a committee of Congress or a scientific society and advocate a cause, could, from his seat by the fireside or at the desk, so illumine the subject with which he had to deal that men stood round him to gather his words, that nothing should be lost, for in the exposition of his subject he illumined everything with clear statement, arising from an exhaustive knowledge and full understanding of results. As the director of the work of research in which other men were engaged, Professor Baird had marvelous insight and skill. The appliances of modern research, alike in the inorganic world and in biology, have come to be multifarious and diverse, and there is this peculiarity about their use : That once used, so that the secret of nature which they were planned to unlock has been revealed, they speedily ^become obsolete, and immediately new keys, new appa- ratus, new devices are necessary. Thus to a large extent skill in research is absorbed in the skill necessary for the development of the agencies of research. A continuous line of research, prose- cuted by a corps of men so that the boundaries of knowledge are carried far forward, can result only from a continuous line of in- ventions in the apparatus of research, and it was here that Baird exhibited his skill. His own devices were many and constant, and ever he was fertile in suggestions to his assistants. No wonder, then, that so many of the secrets of nature were unlocked through his agency. It was in the direction of this work of research that the man Baird stood forth as a giant; it was where his vast knowl- edge of details was most apparent ; it was where his marvellous skill was most shown ; it was where his insight into human char- acter was most exhibited. With clearness he formulated his inter- rogatories ; with aptness he selected his course of procedure ; with judgment he sought the aid of others, and with suggestiveness di- rected their work. And, lo ! his questions were speedily answered. It was in this manner that his own good hands were supplemented by the hands of many, that his own great mind was re-enforced by 76 PHILOSOPHICAL SOCIEXY OF WASHINGTON. the best mental activity of many assistants ; and thus the whole body of men under his control worked together a? one organic in- teger for the increase and diffusion of knowledge among men. In his work with his assistants he scrupulously provided that every one should receive the meed of honor due for successful re- search and treated all with generosity. Many an investigation begun by himself was turned over to assistants when he found that valuable conclusions could be reached ; and these assistants, who were his warm friends, his younger brothers, reaped the reward ; and he had more joy over every young man's success than over the triumphs and honors heaped upon himself from every quarter of the globe. He was the sympathetic counsellor of many men ; into his ears were poured the sorrows and joys of others, and he mourned with the mourning and rejoiced with the rejoicing. To those in need his hand was ready and his purse was open, and many and many were the poor who called him " blessed." Though a man of great force of character, a man of great learning, a man upon whom had been showered the honors of the scientific world, in character he was as simple as a child. He had a fund of " folk-lore," and loved the books and papers written for children. In his later years, weakened with disease and burdened with many labors, he still read St. Nicholas from month to month, and kept the run of every little story, and was glad to be " a child again." His life at home was pure and sweet, and full of joys, for he gave and received love and trust and tender care. But the history of his home life is sacred. Its words and acts abide in the hearts of the wife and the daughter. For many long months he contemplated the day of parting. Labor that knew no rest, responsibility that was never lifted from his shoulders, too soon brought his life to an end. In the summer of the past year he returned to his work by the seaside, that he might die in its midst. There at Wood's Holl he had created the greatest biologic laboratory of the world ; and in that laboratory, with the best results of his life-work all about him, he calmly and philosoph- ically waited for the time of times. Three days before he died he asked to be placed in a chair provided with wheels. On this he was moved around the pier, past the vessels which he had built for research, and through the laboratory, where many men were at work at their biologic investigations. For every one he had a word of good cheer, though he knew it was the last. At the same time, GENERAL MEETINGS. 77 along the pier and through the laboratory, a little child was wheeled. " We are rivals," he said, " but I think that I am the bigger baby." In this supreme hour he was playing with a child. Then he was carried to his chamber, where he soon became in- sensible, and remained so until he was no more. " Blessed are the pure in heart, for they shall see God." BULLETIN PHILOSOPHICAL SOCIETY OF WASHINGTON, MATHEMATICAL SECTION (79) STANDING RULES MATHEMATICAL SECTION. 1. The object of this Section is the consideration and discussion of papers relating to pure or applied mathematics. 2. The special officers of the Section shall be a Chairman and a Secretary, who shall be elected at the first meeting of the Section in each year, and discharge the duties usually attaching to those offices. 3. To bring a paper regularly before the Section it must be sub- mitted to the Standing Committee on Communications for the stated meetings of the Society, with the statement that it is for the Mathematical Section. 4. Meetings shall be called by the Standing Committee on Com- munications whenever the extent or importance of the papers sub- mitted and approved appear to justify it. 5. All members of the Philosophical Society who wish to do so may take part in the meetings of this Section. 6. To every member who shall have notified the Secretary of the General Committee of his desire to receive them, announcements of the meetings of the Section shall be sent by mail. 7. The Section shall have power to adopt such rules of procedure as it may find expedient. 52 (81) LIST OF OFFICERS AND MEMBERS MATHEMATICAL SECTION OF THE PHILOSOPHICAL SOCIETY FOR THE YEAR 1887. Chairman, Wm. B. Taylor. Secretary, R. S. Woodward. Abbe, C. Avery, R. S. Baker, M. Bates, H, H. Billings, J. S. Burgess, E. S. Christie, A. S. Coffin, J. H. C. Curtis, G. E. DeLand, T. L. DOOLITTLE, M. H. Dutton, C. E. Eastman, J. R. Eimbeck, W. Elliott, E. B. Farquhar, H. Flint, A. S. Gilbert, G. K. Gore, J. H. Green, B. R. Hall, A. Harkness, W. Hazen, H. A. Hill, G. W. HODGKINS, H. L. King, A. F. A. Kummell, C. H. Martin, A. Marvin, C. F. McAdie, A. G. McGee, W J Newcomb, S. Paul, H. M. Ritter, W. F. M'K. Robinson, T. Russell, T. Smiley, C. W. Stone, O. Taylor, W. B. Upton, W. W. Wilson, H. C. Winlock, W. C. Woodward, R. S. Ziwet, Alex. (82) BULLETIN OF THE MATHEMATICAL SECTION, 24th Meeting. February 16, 1887. The Chairman, Mr. Wm. B. Taylor, presided. Present, eighteen members and one guest. The Section proceeded to the election of officers for 1887 by ap- pointing a Nominating Committee consisting of Messrs. Farquhar, Baker, and Hill. The Committee nominated Mr. Wm. B. Taylor for Chairman and Mr. R. S.Woodward for Secretary ; these nominees were elected by acclamation. Mr. M. H. Doolittle read a paper on ASSOCIATION RATIOS. [Abstract.] The present communication is an effort in the direction of a science of statistics. It includes the principles involved in my communication* of December 3, 1884, but presents them in a more general manner. Suppose that there are s occasions on which the presence or ab- sence of the phenomena A and B are determined by observation. Suppose that there are a instances of the occurrence of A, and b instances of the occurrence of B, each including c instances in which A is associated with B. There remain s— a— b -f- c instances in which A and B are both absent. If a= b = c, the two phenomena are always found associated, and the association may be regarded as perfect. If either A or B is ever found alone, the association is *The verification of predictions. See Bulletin of Phil. Soc. for 1884, vol. 8, pp. 122-127. (83) 84 PHILOSOPHICAL SOCIETY OF WASHINGTON. imperfect. I assume that the extent of association is a quantity capable of numerical expression, and further assume it = —r. This is tantamount to the assumption that whenever either of the c c ratios or - is constant, the extent of association varies directly as a f) the other ratio, and = 1 when they each = 1. Not-A and Not-B may also be regarded as phenomena whose presence is equivalent to the absence of A and B and vice versa. Not-A, therefore, occurs s — a times ; and Not-B s — 6 times. The following table will hardly need further explanation: Phenomena. Both occur. Neither occurs. Extent of association. A and B c s— a — b-\-c —, ra cyA and Not-B a— c b — c £= a(s— o) (h C )» Not-A and B b — c a— c Not-A and Not-B s— a— b + c (s— a) b (s— a—b + cy (s— a) (s— b) For illustration, let blindness and deafness be the phenomena denoted respectively by A and B. Then the extent of association c 2 between blindness and deafness = —r\ that between sight and deafness = -, -r, &c. (s — a) b I call the above expressions for extent of association indiscrimi- nate association ratios. It is important now to understand that the magnitude of each is determined both by general and special causes. In an ordinary community the indiscriminate association ratio be- tween sight and hearing is very large, nearly =1, for the general reason that most people can see whether they can hear or not, and most people can hear whether they can see or not. If there is a special reason why a larger proportion of men able to see than of blind men shall be able to hear, this special reason will tend to in- crease the indiscriminate association ratio, and a contrary special reason will tend to diminish it. I now seek to obtain a discriminate association ratio, whose magnitude shall be affected by special causes only, and which may MATHEMATICAL SECTION. 85 therefore serve as a measure of their efficiency. The general problem may be stated as follows : Having given the number of instances respectively in which things are both thus and so, in which they are thus but not so, in which they are so but not thus, and in which they are neither thus nor so, it is required to eliminate the general quantitative relativity inhering in the mere thingness of the things, and to determine the special quantitative relativity subsisting be- tween the thusness and the soness of the things. If no special causes are in operation, the number of instances in ab which both A and B occur should be= — according to the general theory of probabilities. The operation of such causes is therefore ab indicated by a difference between the values of c and — Now,J 8 instead of the ratio -, which varies directly as c, let us form a ratio which shall vary directly as c and which shall — 1 when c= a. These conditions give us the ratio ab c i s cs— ab a (s— b) In like manner, instead of the ratio r we have — —. Now, as- b b (s— a) suming that whenever either of these derivative ratios is constant, the required discriminate association ratio varies directly as the other ratio varies, and that it equals unity when they each equal (@a (ib*)* unity, it is found equal to their product = —=—, r^ rr3 * t ab (s— a) (a— by For the phenomena A and Not-B the number of concurrences probable from general causes =— -j and subtracting this quan- s tity from a — c, from a, and from s— b, the indiscriminate . . . (a— c) 2 . (ab— cs) 2 ... association ratio -^ ,^ becomes —=—: —. rr< which diners a (s— b) ab {s— a) (s — b) from the discriminate association ratio for A and B merely in the algebraic sign of the quantity under the exponent. This is as it should be. Sight is precisely as favorable or unfavorable to hear- 86 PHILOSOPHICAL SOCIETY OF WASHINGTON. ing as it is unfavorable or favorable to deafness. In like manner the same discriminate association ratio is obtained for the phenomena Not-A and B, and for Not-A and Not-B. The logical relation be- tween sight and hearing is just as close as that between sight and deafness, as that between blindness and hearing, and as that be- tween blindness and deafness. It is in fact the same relation stated in different words. The sum of the four indiscriminate association ratios is c 2 (a— c)2 (b— cy (s— a— b-{-cy ==1 (cs — ab? ab a (s— b) (s— a) b (s— a) (s— b) ab (s— a) (s— b) Hence the discriminate association ratio = the sum of the indis- criminate association ratios — 1. Since every instance of A or of Not-A is necessarily associated with an instance of B or of Not-B and every instance of B or of Not-B is necessarily associated with an instance of A or of Not-A, this alternative association is perfect, and its extent = 1 whatever A and B may denote. The excess of the sum of the indiscriminate association ratios above unity may, therefore, be taken as a measure of that portion of the aggregate which is peculiar to any special signification of A and B. Such association as belongs necessarily to any two classes of phenomena whatever having been eliminated, the discriminate association ratio measures that residue which indicates special relations. I call c the concurrence residual. If c is less than — , the s s concurrence residual is negative and indicates that special causes prevent oftener than they produce positive association between A and B. If e= and a = s — b, the negative association (or disso- ciation) is perfect, and the discriminate association ratio =1. These conditions signify that the two phenomena are never both present and are never both absent. Denoting the discriminate association ratio by y, the concurrence residual by x, and the class residuals a and b respect- ively by a and /?, we have the equation x 2 and regarding x and y as variables and a and p as constants this equation is represented in Cartesian co-ordinates by a parabola. MATHEMATICAL SECTION. 87 The value of the discriminate association ratio is not affected by interchange of a and b. It is assumed that association and recip- rocal association are equal. The concurrence residual is significant in proportion to its square; and this is in accordance with the general comparative importance of residuals in the theory of least squares. When s is infinite, with a, b, and c each finite, the discriminate c 2 association ratio reduces to the indiscriminate -y. In this case the ab chances are as infinity to one against fortuitous concurrence ; and the extent of association must be regarded as based wholly on special relations. This paper was briefly discussed by Messrs. Gilbert, H. Far- quhar, Baker, and the author. 25th Meeting. March 2, 1887. The Chairman presided. Present, twenty-one members and two guests. A symposium was held on the following problem in probabilities: one-third of the apples on a tree are rotten and one- fourth are wormy, what is the probability that an apple taken at random from the tree will be (1) rotten only; (2) wormy only; (3) both rotten and wormy; and (4) SOUND ? The discussion was begun by Mr. M. Baker who gave an analyt- ical statement of the conditions of the problem and concluded that the problem was an indeterminate one until some assumptions were introduced. Without introducing anything additional to that stated he concluded that the four probabilities were respectively _?_^ _?_^ _d ± _dPi- 4 s ;^2- 3 s ; Vz- s 12 ; Pi- s ; where d = the number of sound apples and 8 the total number of apples. 88 PHILOSOPHICAL SOCIETY OF WASHINGTON. Mr. Doolittle, proceeding on the hypothesis that the problem is indeterminate, gave an infinite series of possible values for the respective probabilities. But he thought the problem should be understood as determinate, and assigned -A- as the proper value for the third probability. Mr. Hill expressed the opinion that the probability TY for a rotten and wormy apple is the proper value, but gave a solution of the problem by means of double integrals which brought out a dif- ferent result. Messrs. Curtis, Elliott, and Farquhar gave different solutions leading to y 1 ^- for the third probability. Mr. Farquhar objected to the result i as involving the absurdity that if one-fourth are wormy the probability of the combination is exactly the same for all values of the rotten between £ and f ; and also further objected to calling a probability " indeterminate " be- cause it was not a certainty. Mr. Martin gave a brief history of the problem, which appeared originally in his Mathematical Visitor,* and of which he gave three solutions leading to £ for the third probability. He stated that the correctness of his solution depended on the correctness of the view that all possible values of any one of the probabilities are equally probable. The subject was further discussed by Messrs. Gilbert, Christie, and Woodward. Mr. Hill also read a letter from Prof. A. Hall relating to the problem. The discussion was closed with some remarks by the Chairman on the language of the problem and its proper interpretation. * The Mathematical Visitor; edited and published by A. Martin. 4°. Erie, Pa. 1881. Vol. 1, No. 4, January, 1880, p. 115, problem 180; solu- tions pp. 180-181. MATHEMATICAL SECTION. 89 26th Meeting. March 16, 1887. The Chairman presided. Present, sixteen members. Mr. Christie read a paper on A PROBLEM IN PROBABILITIES. In this paper he reviewed the conditions of the question in prob- abilities discussed at the previous meeting. He considered it a question susceptible of a definite answer, dependent only on a logi- cal and mandatory application of the elementary principles of prob- ability. In his analysis he derived expressions for the possible combinations of the several events and deduced therefrom a func- tion representing the probability of the probability of the compound event (rottenness and worminess), the variable in this function being the probability sought. The value of the variable making the func- tion a maximum was taken as the required probability, the result being j\. If n = total number of apples, r — number rotten, w = number wormy, x= number both rotten and wormy, then and the chance of a particular apple being both rotten and wormy is -. When x1 and x" are integral the chance is either —or — , that n n n' a/+ x" is — J— • When n, r, w are all infinite, the case of continuous rw number, this chance is —=-. n? Mr. Stone took the ground that the problem is susceptible of but one interpretation, and gave a geometric solution leading to TV for the probability of the compound event. He also gave some in- stances of allied questions in dependent probabilities. An animated discussion, extending over the remaining time of the meeting, then followed. Of those who participated in the dis- cussion, Messrs. Christie, Curtis, Doolittle, Elliott, Hill, Kummell, Stone aud Ziwet considered the problem determinate, while Messrs. Baker, Harkness, and Woodward considered it indeterminate. 90 PHILOSOPHICAL SOCIETY OF WASHINGTON. 27th Meeting. March 30, 1887. The Chairman presided. Present, twelve members and two guests. Mr. R. S. Woodward read a paper on THE FREE COOLING OF A HOMOGENEOUS SPHERE INITIALLY HEATED TO A UNIFORM TEMPERATURE. [This paper appeared in full in the Annals of Mathematics. 4°. Char- lottesville, Va. 1887, June ; vol. 3, no. 3, pp. 75-88. Also separately- printed.] Remarks were made on this paper by Messrs. Kummell, Hill, and the Chairman. , Mr. Kummell read a paper on THE BRACHISTHODE ON THE HELICOID. [Abstract.] The characteristics of this class of curves and the methods of com- puting their lengths in the several cases were explained and dis- cussed. Accurately constructed stereoscopic diagrams of several of these curves were exhibited. [This paper is expected to appear in the Mathematical Visitor.] 28th Meeting. April 13, 1887 The Chairman presided. Present, nineteen members and one guest. Mr. G. W. Hill read a paper on THE MOTION OF HYPERION. Although designed to meet the special case presented by Hyperion, Mr. Hill's paper treated the general problem of three bodies under the restrictions that they are all nearly in the same plane and that MATHEMATICAL SECTION. 91 the mass of the one whose motion is sought is negligible in compar- ison with the masses of the other two. The potential function for the disturbed body was put in a general form for the purpose of ascertaining the most advantageous variables for its development, and some of the particular forms were derived and discussed. Mr. Hill also indicated the methods which might be most advantage- ously followed in the application of his theory to Hyperion. This paper was discussed by Mr. A. Hall, who alluded to the unique character of the motion of Hyperion, and stated some of the more interesting facts concerning the observations of this satellite and the failure of the theories thus far advanced to represent its motion. Other remarks were made by the Chairman and Mr. Woodward. [This paper appeared in full in the Annals of Mathematics. 4°. Char- lottesville, Va. 1887, June ; vol. 3, no. 3, pp. 65-73. Also separately- printed.] Mr. A. Hall presented a paper* on THE PARALLAX OF a TAURI. He gave a historical account of the early attempts at the deter- mination of stellar parallax together with some of the results at- tained. He exhibited in tabular form the principal data on which his value for the parallax of a Tauri depends. In contrasting his result with the larger value for the same star determined by Struve he stated that his values for parallax are generally smaller than those of other observers. The brief discussion which followed was participated in by Messrs. Eastman, Paul, and others. 29th Meeting. April 27, 1887. The Chairman presided. Present, thirteen members. Mr. A. S. Flint read a paper on the most probable value of the latitude and its theoret- ical WEIGHT FROM ENTANGLED OBSERVATIONS OCCURRING IN THE USE OF TALCOTT's METHOD. In this paper Mr. Flint showed first how to express the weighted 92 PHILOSOPHICAL SOCIETY OF WASHINGTON. mean value of the latitude and its weight in the most general case of entanglement in terms of the results from individual pairs of stars and their symbolical weights. To find the numerical values of these symbolical weights he made use of the principle that the weights of the individual results must be such as to make the probable error of the weighted mean a minimum. After treating the most general case he considered some of the speciahcases occur- ring most commonly, and deduced practical formulas for computing the weights of individual results. In illustration of his methods he gave the details of the numerical operations in one of the more com- plex cases presented in actual work. In the discussion which followed, Mr. Harkness derived, by a different and less complex process, some of the formulas given by Mr. Flint. Others participating in the discussion were Messrs. Paul, Farquhar, Stone, and Woodward. Mr. E. B. Elliott began the presentation of a paper on THE MUTUAL ACTION OF ELEMENTS OF ELECTRIC CURRENTS. 30th Meeting. May 11, 1887. The Chairman presided. Present, ten members and two guests. Mr. E. B. Elliott continued his paper on THE MUTUAL ACTION OF ELEMENTS OF ELECTRIC CURRENTS. He stated that Ampere's theory of such currents involves the assumption that the action between the elements is limited in direc- tion to the line joining them. In conformity with this assumption the result reached by Ampere, and now usually given in text books, is that the action is proportional to § cos cos 6'— sin sin 0' cos u>, in which and 6' are respectively the angles between the directions of the elements and the line joining them, and w is the angle be- tween the two planes defined by the directions of the elements and the line joining them. MATHEMATICAL SECTION. 93 In his own investigation Mr. Elliott makes no assumption or restriction with reference to the direction of the action of the ele- ments and finds the action proportional to the following expression : (cos -f- sin . i) (cos 0' -\- sin 0' cos w . i -}- sin 0' sin u> . j)= cos cos 0' — sin sin tf cos have the same signification as stated above, and i,j and ij (or its equivalent k) are quadrantal versors. The first term of this formula represents action in the line joining the elements ; the second term represents action in the plane of the connecting line and one of the elements and perpendicular to the connecting line ; the third term represents action in a direction at right angles to the plane just mentioned ; and the fourth terra rep- resents torsion in a plane perpendicular to the connecting line. The actions resulting in some special cases, as when the elements lie in one plane, etc., were explained and discussed. [This paper was presented to the American Association for the Advance- ment of Science at its New York meeting, August, 1887, and appeared in the Electrical World; a weekly review, etc. fol. New York, 1887, Au- gust 27 ; vol. 10, no. 9, p. 116. Also separately printed.] Mr. Hill, following Maxwell, gave some of the principal steps in the process which leads to Ampere's result, indicating that that process differs from Mr. Elliott's in leaving out of account cer- tain couples and in assuming a certain undetermined quantity to be zero. The paper was further discussed by Mr. Harkness, the Chair- man, and others. Mr. Doolittle began the presentation of a paper on association ratios. 94 PHILOSOPHICAL SOCIETY OF WASHINGTON. 31 st Meeting. May 25, 1887. The Chairman presided. Present, sixteen members and one guest. Mr. M. H. Doolittle continued his paper on ASSOCIATION RATIOS, which consisted chiefly in a review and criticism of an article* by- Mr. G. K. Gilbert on Finley's Tornado Predictions. The follow- ing is an abstract of Mr. Doolittle's paper : By Mr. Gilbert's notation : s = whole number of predictions. p = number of positive predictions. o = number of occurrences. c= number of verifications of positive predictions. p' = s — p = number of negative predictions. o' = s — o — number of non-occcurrences. o — c = " measure of the failure in inclusion." p — c = " measure of the failure in exclusion." We should also have for consistency c = measure of success in inclusion. c' = s — o — p + c= measure of success in exclusion. He says, "If inclusion and exclusion are equally important their measures bear the same weights." This is as true for success as for failure, but Mr. Gilbert gives to the measure of success in exclusion no weight whatever, and entirely disregards it. He has o -(- p — 2c = measure of the general failure of prediction. We should also have s — o — p-\-1c= measure of the general success in prediction. The latter measure consists of the "favorable cases;" the former * American Meteorological Journal. 8°. Detroit, Mich., 1884, Sep- tember; vol. 1, no. 5, pp. 166-172. MATHEMATICAL SECTION. 95 of the "unfavorable;" and the "ratio of verification (the favorable cases divided by the sum of the favorable and unfavorable," becomes s — o — p + 2c c-\-c v = - — = —! s s And this is Mr. Finley's method of computation. Mr. Gilbert then employs a process to which he gives no name, but which may be called the elimination of hypothetical chance. on He estimates that — verifications of positive predictions might have been expected if the same number of positive predictions had been made at random, and sets these cases aside as proving neither discrimination nor want of it. In effect, he subtracts — from each s of the quantities o, p, and c, and proceeds with the residuals. This portion of his reasoning is regarded as sound, and the process may be applied with great utility to properly formed ratios. The ratio v is k c-\- c' c + c' s ~p-\rp' op To eliminate hypothetical chance, — should be subtracted from o'p' each of the quantities c and p, and — from c' and p'. Denoting the result by 96 PHILOSOPHICAL SOCIETY OF WASHINGTON. under others, and it is not maintained that it has any scientific value. Mr. Gilbert says that he hopes " to show that Mr. Finley's method involves a serious fallacy. This fallacy consists in the assumption that verifications of a rare event may be classed with verifications of the predictions of frequent events without any system of weight- ing." It is not perceived that Mr. Gilbert has furnished any such system. The fallacy, perhaps, consists rather in the supposition that any valuable result can be obtained by averaging the percent- ages of verification of heterogeneous classes of predictions. Mr. Finley correctly computed his indiscriminate percentage of verifi- cation, and thereby furnished a striking and, perhaps, much-needed illustration of the*worthlessness of such computations. The elimi- nation of hypothetical chance from such mixed percentages merely renders their worthlessness less apparent. This paper was briefly discussed by Messrs. Curtis, Farquhar Hill, Baker, and Woodward. Mr. H. Farquhar presented a solution and generalization of a problem, proposed in Science* requiring the division of a rectangle, by a single step-cut, into two parts which when put together will form a square. Mr. Marcus Baker presented a communication on A COLLECTION OF SOLUTIONS OF THE TRISECTION PROBLEM. [Abstract.] The communication consisted of an informal statement from notes and memoranda of progress in the direction of an exhaustive col- lection of real solutions of the problem to trisect an angle. It was pointed out that, though the problem was a very old and very famous one, energy is constantly wasted in its study by those igno- rant of what has been done, and that this misdirected energy might, in large part, be due to the want of any satisfactory digest of results hitherto attained. The author had himself felt the need of such a digest, and, finding none, had some years ago begun a collection of * See Science. 4°. New York, 1887, May 20; vol. 9, no. 224, p. 488, query 5. MATHEMATICAL SECTION. 97 notes and memoranda, with a view to the preparation of a fairly complete collection of solutions of the problem and the preparation of a bibliography. Progress in the work had been slow, and the results are still very incomplete, especially the bibliographic part, which was deemed the most important. The present collection of notes contained about a dozen different solutions of the problem and a suggested classification for a digest of the subject as follows : 1. Historical Introduction. 2. Trisection by the conic sections. 3. Trisection by special or higher curves. 4. Trisection by mechanical devices. 5. Trisection by approximation. 6. False trisections. 7. Bibliography. Of the trisections by the conic sections five were enumerated, viz : 1. By parabola and circle. 2. By parabola and parabola. 3. By parabola and hyperbola. 4. By the equilateral hyperbola. 5. By the hyperbola, whose asymptotes form an angle of 120°. Trisections by the following curves were also enumerated : 1. Conchoid of Nicomedes. 2. Conchoid on circular base = trisectrix = planetary curve of Ptolemy = special case of limacon of Pascal. 3. Cycloid. 4. Epicycloid or trochoid. 5. Quadratrix of Dinostratus or Hippias of Elis. 6. Quadratrix of Tschirnhausen. 7. Spiral of Archimedes. Respecting the cissoid of Diodes, it was remarked that no solu- tion of the trisection problem, by its aid, had been found. Also respecting the cycloid, which Sir Isaac Newton is said to state may be used to trisect an angle, no solution by means of it had been found, but the author had himself made one recently. 53 98 PHILOSOPHICAL SOCIETY OF WASHINGTON. Of the various mechanical devices used for trisection the liukage of Thomas of Ceva was given, others being referred* to only. Of false trisections, the number was stated to be very large and of unequal value, some giving close approximations and others failing ignominiously. Finally, in the bibliography, now containing some fifty references, and believed to be only the beginning of a reason- ably full list, it was proposed to make an authors' catalogue of en- tries, and to follow each reference with a very brief characterization of the contents of the article. The foregoing scheme had been laid out but latterly had made no progress, and the opinion of the section was sought as to the desira- bility or advisability of carrying the work on. Mr. Curtis made the following remarks: Six or eight years ago I began a similar collection of trisection methods, in looking over which I find a number of solutions addi- tional to those presented by Mr. Baker. The following six belong to the class in which an angle is trisected by means of curves : (1) ^-\- x2y — axy -\-hx 2 = o ; the ophiuride of Dietrich Uhlhorn (1764-1837). (2a2 -f)\(2) x = 4a2— ?/2 the polyode of Dr. "Win. Hillhouse,* Prof. J. W. Nicholson,f J. Bruen Miller.J (3) Ax2 + 12?/ 2= (1/1^4. yy_ Sy i/T=tf+ 4. Dr. Wm. Hillhouse. (4) [Curve drawn, but equation not given.] Ibid. *The Analyst; edited and published by J. E. Hendricks. 8°. Des Moines, Iowa. 1882, November, vol. 9, no. 6, pp. 181- i 84. See also same. 1876, September, vol. 3, no. 5, p. 151. f Same. 1883, March, vol. 10, no. 2, pp. 41-43. See also The Multisector and Polyode. By Prof. J. W. Nicholson, M. A., Professor of Mathematics. Louisiana State University. 8°. New Orleans ; published at the Times- Democrat. 14 pp. % Van Nostrand's Engineering Magazine. 8°. New York, D. Van Nos- trand, 1880, March, vol. 22, no. 135, pp. 206-209. MATHEMATICAL SECTION. 99 t+ivr-^+q-y) V2 2 >m (6) x 2 -\- (Sy— 4ff = r2 im Dr. William Hillhouse, of New Haven, has not only shown that the last five curves may be used for trisecting an angle, but has devised instruments for describing them. This latter step, as I view the problem of trisection, is a necessary part of any real solu- tion by means of curves. The simple determination of the equations that will satisfy the analytical conditions of trisection, without the instrumental means for describing the curves, does not constitute a solution of the problem. It is essentially something to be done, not something merely to be proved, and its fame arises from the im- possibility of making the trisection of an angle by means of a ruler and pair of compasses. Any proposed solution, therefore, must in- dicate a geometrical instrument for accomplishing it, and the nature of the motion applied therein determines the character of the solu- tion. A class of solutions, regarded the most elegant of all, is that in which link machines trisect the angle directly, without the aid of interposed curves. Of this class I have found three instruments, invented respectively by the Marquis de l'Hopital (1661-1704), A. B. Kempe, and Professor Sylvester. That of l'H6pital is a com- bination of link and sliding motion ; those of Kempe and Sylvester are pure linkages. With respect to the two, latter, I wish to call attention to the elementary character of the solution. Euclid's postulates require us to be able to draw a straight line and a circle, and it is frequently assumed that they imply the use of a straight- edge and a pair of compasses. But, manifestly, any other instru- ments that can describe the circle and the straight line satisfy equally the requirements of the postulates. Moreover, the use of a straight edge assumes as accomplished the very thing proposed to be done ; whence the straight-edge is not an original instrument for describing a straight line. Such an instrument is given by the linkage of Peaucellier. More originally, therefore, than by the straight-edge, the postulates of Euclid may be assumed to imply the use of pure link motion. Wherefore, if pure link motion be considered as postulated by Euclidian geometry, the trisection of an angle becomes one of the simplest of geometrical problems. 100 PHILOSOPHICAL SOCIETY OF "WASHINGTON. Mr. Kummell remarked that the supposed analogy between the duplication of a cube and the trisection of an angle 'does not exist, since the latter requires a cubic with three real roots, while the former requires a cubic having one real and two imaginary roots. The subject was further discussed briefly by the Chairman aud Mr. Bates. 32d Meeting. October 19, 1887. The Chairman presided. Present, sixteen members and one guest. Mr. G. W. Hill read a paper on THE INTEGRATION OF DIFFERENTIAL EQUATIONS ADMITTING PE- RIODIC INTEGRALS. [Abstract.] The independent variable being conceived as time, a system of ordinary differential equations may be said to admit periodic inte- grals when the values of the dependent variables, either exactly or with an approximate tendency, after a certain lapse of time, repeat their series of values. In the latter case the longer the lapse is made the more nearly is the repetition brought about. Strange as it may seem, this subject, except in the case of simply periodic inte- grals, is, at present, not completely understood. The text-books on differential equations are almost wholly engaged with the cases, which, by certain artifices, can be integrated in finite terms or re- duced to quadratures. In the treatment of physical problems, however, we seldom meet with equations of this class. Far more frequently it is found that methods of approximation must be re- sorted to. Cauchy appears to be the author who has done the most for the elucidation of this part of the subject. His memoirs are in his later Exercises and in the volumes of the Comptes Rendus for 1856 and 1857. In this paper the mode in which simply periodic integrals arise was discussed, and the theory afterwards illustrated by treating the following problem: Find the conditions of motion of any number of material points mov- MATHEMATICAL SECTION. 101 ing about a centre under the action of central forces whose potential is a function of the sum of the squares of the radii vectores. The differential equations of this problem, in the case where the radii are supposed to describe no areas, were first integrated by Binet* But the addition to the forces of the terms arising from cen- trifugal action much enhances the interest of the problem. The chief point of interest brought out by the solution was that while the directions of the points, whether as seen from the centre or from each other, all return to the same values after the lapse of a certain time, as do also the ratios of the radii vectores, the absolute values of the latter have all a factor whose period is generally dif- ferent from the former. Thus the movement of the system may be conceived as taking place under the operation of two distinct causes, viz : the first producing a revolution of all the points about the centre in closed curves in the same time, while the second, having a different period, changes the scale of representation of the system in space. [This paper appeared in full in the Annals of Mathematics. 4°. Char- lottesville, Va. 1887, October; vol. 3, no. 5, pp. 145-153.] Mr. Hill's paper was briefly discussed by Mr. A. Hall and the Chairman. Mr. A. Hall read a paper on EULER's THEOREM (GENERALLY CALLED LAMBERT'S). [Abstract.] This theorem is well known to astronomers and is very useful in computing the orbits of comets. The time of the passage of the comet from one point to another of its orbit is expressed by means of the two radii vectores drawn to the points, and the chord joining these points. For many years, and by irikny writers even of the present time, this theorem is attributed to Lambert. Mr. Hall stated that it was first given by Euler about 1743. He gives two proofs for the parabola, and then extends the theorem to the ellipse. For this case Euler gives first an expression for the peri- helion distance in terms of the sum of the two radii vectores and the chord. He then gives an approximate expression for the time of describing the arc in terms of the perihelion distance, the radii * Journal de mathematiques ; par J. Liouville. 4°. Paris, 1837. 1st series, vol. 2, p. 457. 102 PHILOSOPHICAL SOCIETY OF WASHINGTON. vectores and the eccentricity of the ellipse, and directs us to sub- stitute the value of the perihelion distance. Euler does not, there- fore, give an explicit expression for the time in terms of the radii vectores and the chord, although he points out how this may be done. Considering the results that he obtained, Mr. Hall thinks that this theorem, with respect to all the conic sections, should be known by the name of Eider. Remarks on this communication were made by Messrs. Hill, Stone, and Winlock. 33d Meeting, November 2, 1887. The Chairman presided. Present, fifteen members and one guest. Mr. E. B. Elliott gave a brief description of a new form of com- puting machine, which prints and arranges in the usual form for addition any series of numbers and then prints their sum, the work of the operator being merely mechanical as in the use of the type- writer. Although designed especially for performing aud printing work in addition, the machine may also be used for multiplication and division. Mr. Wm. Harkness presented a paper on THE CONSTANT P IN OBSERVATIONS OF TERRESTRIAL MAGNETISM. It was explained that this paper arose from a correspondence in Nature concerning the modes of computing the constant. In a letter published in the number of that journal for August 18th, 1887, Mr. Harkness referred to an expression for P given in Stewart and Gee's Practical Physics, and suggested a more convenient form for logarithmic computation. In the number for September 8th, Mr. William Ellis gave another but somewhat less accurate expression for the computation of P; and in the number for September 29th, Prof. Arthur W. Rucker gave what he considered a more accurate expression than either of the others. Starting from the fundamental equations of Gauss, Mr. Hark- ness derived a formula for P correct to terms of the second order inclusive. He then showed that Riicker's formula, which pur- MATHEMATICAL SECTION. 103 ported to give terms of the second order, was incorrect, and pointed out that the error in Riicker's process consisted in expanding to terms of the second order an expression which included only terms of the first order. This paper was briefly discussed by Messrs. Hall, Abbe, Kum- mell, and Harkness. This and other related papers appeared in Nature* Mr. R. S. Woodward read a paper on THE CONDITIONED COOLING OF A HOMOGENEOUS SPHERE. The salient features only of this paper were presented. The funda- mental assumptions and analytical conditions of the problem were indicated, and especial attention was directed to the distinction be- tween the case of " conditioned cooling" and that of "free cooling," which latter was discussed by the author, at the 27th meeting of the section. It was shown that the solution for the more complex case of " conditioned cooling " is derivable by a comparatively simple process from the solution for "free cooling." The probable discrep- ancy between the data presented by the earth as a cooling sphere and those assumed in the solution of the problem, and the additional data requisite for a more complete solution were pointed out. The presentation of the paper was followed by an informal dis- cussion participated in by nearly all present. This discussion re- ferred chiefly to the physical features of the earth as a cooling sphere, and served to disclose a diversity of opinion concerning the con- ductive and convective properties of such large masses. [This paper appeared in full in the Annals of Mathematics. 4°. Char- lottesville, Va. 1887, October; vol. 3, no. 5, pp. 129-144.] * Nature, a weekly illustrated journal of science. 4°. London, 1887-1888. 1887, Aug. 18, vol. 36, no. 929, p. 366. On the constant P; by Wm. Harkness. Sept. 8, vol. 36, no. 932, p. 436. Same; by Wm. Ellis. Sept. 29, vol. 36, no. 935, p. 508. Same ; by A. W. Riicker. Dec. 8, vol. 37, no. 945, pp. 127-128. Same ; by Harkness and re- joinder by Riicker. 1888, Jan. 19, vol. 37, no. 951, pp. 272-273. Same; by Harkness and re- joinder by Riicker. 104 PHILOSOPHICAL SOCIETY OF WASHINGTON. 34th Meeting. November 16, 1887. The Chairman presided. Present, ten members. Mr. Ormond Stone read a paper on THE ORBIT OF HYPERION. [Abstract.] The principal difficulty in the integration ofthe equations of motion in the case of the problem of three bodies arises in the integration of terms involving the inverse powers of the distances between the dis- turbed and disturbing bodies. When the ratio between the radius vectors is not too near unity, the inverse powers referred to can be developed in rapidly converging series in terms of cosines of multiples of the elongation. When, however, these ratios do not differ greatly from unity the convergence of the series mentioned is very slow. If, in addition, the mean motions of the two bodies are nearly com- mensurate, the ordinary methods of solving the problem become in- applicable. Such a case presents itself in the determination of the perturba- tions of Hyperion produced by Titan. On the other hand the mutual inclination of the orbits of these satellites is so small as to have eluded detection ; the eccentricity of the orbit of Titan is less than 0.03, and the position of the aposaturnium of Hyperion so nearly coincides, at least at present, with the point of conjunction of the two satellites as to give rise to a suspicion that the eccentricity of its orbit is, in reality, small, and that the apparent eccentricity is principally due to the perturbations produced by Titan. In view of these circumstances, that part of the disturbance has been investigated, which may be determined by neglecftng the mutual inclination and the eccentricities of the orbits of both bodies, reserv- ing a discussion of the remaining portion for another paper. It was accordingly assumed that r = a (1 + ar cos -f a2 cos 20 -f- ... ), _ = n (1 + n r cos -f n2 cos 20 -J- . . . ) ; where r and w are the radius vector and longitude in orbit of Hype- rion, is the mean angular distance between the radius vectors of MATHEMATICAL SECTION. 105 Titan and Hyperion, a and n are the mean values of r and w, and av nlt etc., are constants to be determined. In the differential equa- tions of motion for r and w, those terms not containing explicitly the mass of Titan were expanded by Taylor's theorem into series of sums of terms containing cosines of multiples of affected with con- stant coefficients ; while the terms containing the mass of Titan ex- plicitly were expanded mechanically into a series of cosines of mul- tiples of by means of assumed values of the coefficients. Equating the coefficients of the cosines of equal multiples of 0, a number of equations were obtained from which to derive a corresponding num- ber of the quantities av nlf etc. With these new values were ob- tained and the process repeated. Instead, however, of considering in' (the mass of Titan) as known, a3 was assumed to be given and m' was considered as one of the unknowns. [This paper appeared in full in the Annals of Mathematics. 4°. Char- lottesville, Va., 1887. Vol. 3, No. 6, p. 161.] Brief remarks on Mr. Stone's communication were made by the Chairman and by Messrs. Baker, Hill, and Kummell. Mr. E. B. Elliott presented a paper on the quotients of space-directed lines. He wrote down some of the fundamental relations of this analy- sis and explained the nature and properties of the special symbols employed. He called attention to the lectures of Hamilton on quaternions, and to his "letters" on the same subject, as they ap- pear in Nichol's Cyclopaedia;* and commented on the transition from Hamilton's primary conception of a quartemion as a quotient of two directed right lines in space to his secondary conception of a quaternion as the sum of a directed right line and a number. The presentation of this paper was followed by a discussion, in which Messrs. Baker, Hill, Stone, Woodward, and the Chair- man participated. * See A cyclopaedia of the physical sciences, etc., by J. P. Nichol. * * 8°. London and Glasgow, 1857. pp. 625-628. 106 PHILOSOPHICAL SOCIETY OF WASHINGTON. 35th Meeting. November 30, 1887. The Chairman presided. « Eleven members present. Mr. E. B. Elliott continued his remarks, begun at the last meeting, on THE QUOTIENTS OF SPACE-DIRECTED LINES. [Abstract.] Mr. Elliott said that the quotient of two space-directed lines is not a line, but is abstract. It is a quantity which applied as a mul- tiplier to one of the space-directed lines will produce the other. He then gave as an illustration of this principle its application to the problem of the mutual action of the elements of electric currents. Let [i and p! represent, respectively, in length, current strength, and direction, two elements of electric currents. P and p' represent, respectively, in length and direction, the lines connecting the centers of the elements. represent the angle made by the element p. with the line connecting the elements p and // ; that is, with p. 4> represent the angle made by the element pf with its rectan- gular projection in the primary plane ; that is, the plane determined by the element p. and the connecting line p.

sin

cos denoting the angle which the plane of // and p' makes with the plane of p. and p, the direction of the resulting action will be expressed by the following formula: U-XU-? = cos cos (?— sin sin (f cos n and assume the auxiliary formula (p + q) n -pn= a; ... (1) also assume d such that S„ „,— a = d, x, n ' whence & x , n-d+Pn= (P + . Boss' declination standards Ix 53 Botany, List of papers on. (See also Bi- ology :) on some minute fungi. J.S.Billings. Ab- stract 1 42 descriptions of new species of fossil plants from Alleghany Co., Virginia; with some remarks on the rock seen along the Chesapeake and Ohio Railroad, near the White Sulphur Springs of Greenbrier County, West Virginia. F. B. Meek. Read by T. QUI. In full. 2 plates 162, 11 (20) on the cause and remedy of the potato rot. L. D. Gale. Title only 1 97 [plants common to Japan and eastern America.] A. Gray. Abstract il 42 the climate of plants. L. D. Gale. Ab- stract il 1S3 the natural system. of plants. L. F. Ward. Title only 11 W, 187 field and closet notes on the flora of Wash- ington and vicinity. L.F.Ward. Ab- Stract lv 04 on the compass plant. B. Alvord. Refer- ence v 106 the flora of the Laramie group. L. F. Ward. Reference vlii 17 our city shade-trees, their foes and their future. C. V. Riley. Reference x 7 •on the geographical distribution of fossil plants. L.F.Ward. Reference x 28 Boundary line between Alaska and Siberia, iv 123 Boutelle, C. O., remarks on deflection of rivers vil 24 Bowditch, N., and the Mecanique Celeste, vlii xxxvi Bowyers and fletchers ix 44 Boyle, R., cited on atomic philosophy vil xlv Boyle's law v 139 Brachisthode vi 124 on the helicoid x 90 Brain and phosphorus v 75 temperatures.^ v 75 Brainard's Arctic exploration ix 11 Bremiker, Dr., cited on alignment curves. vl 124, 126 Brewer, Prof. W. H., remarks on the potato rot i 97 Brianchon, cited on Feuerbach's circle, viii 45 Brooks, W. K., communication on the em- bryology of Lingula and the systematic relations of the Brachiopods. Title only tit 33 INDEX TO VOLUMES I-X. 127 Brown, Judge A., cited on difficulty of de- termination of sound direction viii 12 Brown, W. R., cited on conservation of energy vii 62 force and matter vii 31 Buccinum undatum iii 75 Buehan, cited on barometric pressures i 108 Bulletin, Cost of printing v 177 Distribution list of iii 159 of the Mathematical Section vi 121. -vii 87, viii 37, ix 53, x 79 of the Society, Function of the i x Rules for publication of. i ii, ii vii, iii vii, iv 13, v 13, vi xxxiii, 135, vii xiii, viii xiii, ix xiii, x xiii Bulletins, Note on x 113 Bulwor, J, cited on visible speech vi 54 Buoys, Drifting vii 14 Burchard, H. N., communication on the sil- ver question. Abstract iii 109 remarks on agricultural production vii 20 Burdon, W., Solution of a geometrical prob- lem by iii 04 Bureau of Ethnology x 57 Burger, Franz, Electric investigations by..v 47 Burnott, S. M., communication on color per- ception and color blindness. Abstract and reference iv 54 refraction in the principal meridians of a triaxial ellipsoid; regular astigmatism and cylindrical lenses. Reference vi 4 the character of the focal lines in astig- matism. Abstract vi 45 why the eyes of animals shine in the dark. Abstract and reference vii 13 Are thore separate centres for light-, form-, and color-perception ? Abstract and reference vii 72 the Javal and Schiotz ophthalmometer. Titleonly viii 11 Busey, S. C, communication on the gather- ing, packing, transportation, and ex- posure of fruits for sale. Title only. ..ii 16 the influence of the cardiac and respira- tory movements upon the motion of the lymph. Abstract and reference... .ii. 133 the relation of the meteorological condi- tions to the summer diarrhoeal dis- eases. Abstract and reference iv 165 the influence of the constant use of high- heeled shoes upon the health and form of the female, and upon the relation of the pelvic organs. Abstract v 117 Butcher, H. B., communication on two im- mense meteorites at Conception and San Gregorio, Mexico. Reference i 24 Page. Butler, J. D., communication on prehistoric copper. Titleonly ii 185 Byasson, H., cited on phosphorus and cere- bral activity v 75 By-Laws. See Standing Rules. Calcium sulphide. Clock faces coated with, iii 33 Calendar of the Society vii ixii, viii xxx, ix xxvii, x xxxi Calendars and Time Standards', List of papers on : on a Gregorian calendar. E. Frisby. Ab- stract i 75 onaproposed reformation of the Gregorian calendar. J. E. Hilgard. Abstract.M 29, 30 calendar formulae. E. B. Elliott. Abstract, ii 37 a calendar proposed by a Persian astrono- mer in 1079. W. B. Taylor. Abstract.M 38 adjustment of the calendar. E. B. Elliott. Abstract ii 59 standards of time— international, sec- tional, and local. E. B. Elliott. Ab- stract ii 137 meridional time for railway and tele- graphic purposes. E. B. Elliott. Ab- stract ii 202 on a system of standard time. A. S. Chris- tie. Abstract v 112 the action of the International Geodetic Association as to an initial meridian and universal time. R. D. Cutts. Ab- stract vi 106 California, Geology of northern ix 4 Latest volcano in ix 46 Cambrian system in the United States and Canada vi 98 Campagna, Eucalyptus on the vi ^36 Capron, Horace, communication on Japan. Title only ii 79 Death of. viii 8 Carbonate deposits of Leadville, Colo vi 32 Care of pamphlets viii 29 Carpenter, Dr. W. B., cited on binocular mi- croscopes iv 35 Cartesian philosophy vii xli Caspian Sea, Altitude of ii 34 Catalogue of astronomical papers ii 95 of stars prepared at U. S. Naval Observa- tory i 74 Catlin, cited on color, number, and theology of Indians Ii 175 Cells found in human fseces ix 35 Census, Mortality statistics of the Tenth, iv 1G4 128 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Census, Vital statistics of the Tenth vlll 4 Centre of population of United States i 35 United SJates 1 22 Centres for light-, form-, and color-percep- tion vll 72 Ceremonial institutions, Origin of certain..lx 19 Cernuschi, cited on bi-metallism iii 108 Chadwick. Lt. Com'd'r F. E., cited on sound anomalies 34 Challis, Prof. J., cited on elasticity v 152, 154 force v 128 Chamberlin, T. C, communication on What is a glacier? Abstract vll 38 the varying attitudes of former level surfaces in the Great Lake region and the applicability of proposed explana- tions. Title only ix 15, 10 remarks on the loess of Iowa and Ne- braska iv 121 Champlain, Ice on Lake 11 (22; Changes of terrestrial level surfaces due to variations in the distribution of super- ficial matter vll 92. 101, ix 15, 53 Chapman's Flora of the Southern States, iv 99 Charles, Law of v 139 Charleston earthquake 1x37,38, x 17,28 Charts of archaeology 11 72 Chase, Salmon P., Resolutions on death of..l 87 Chatard, T. M., remarks on earth tremors, vlll 28 Chemical equivalency vil xlvii rays v 135 side of vitality v 53 Society, Invitation from vlll 29, Ix 46 theory of volcanism vl 90, 93 Chemistry, Li»t of papers on : [exhibition of apparatus for the genera- tion of ozone.] B. F. Craig. No ab- stract 1 52 on the cause and remedy of the potato rot. L. D. Gale. Title only 1 97 on the chemistry of the Bessemer pro- cess. C. E. Dutton. Title only 1 98 on the atomic volumes of crystallized and double salts. F. W. Clarke. Refer- ence 1 103 on the molecular heats of similar com- pounds. F.W.Clarke. Abstract 1104 on the coloring agent of gems. F. M. End- lich. Abstract 11 31 the estimation of manganese as pyrophos- phate. C. E. Munroe. Communicated by T. Antisell. Reference 11 132 chemical remarks on terrestrial geogony. T. Antisell. Title only 11 132, 133, 134 Page. Chemistry, List of papers on—Cont'd, observations on 'chemical molecular changes. T. Antisell. Title only Ill 28 the origin of the chemical elements. L. F.Ward. Title only ..Ill 33 a case of peculiar corrosive action on me- tallic tin. J.W.Osborne. Title only.MV 44 determination of the specific gravity of solids by the common hydrometer. C. E. Munroe. In full vl 26 the periodic law of chemical elements. F. W. Clarke. Abstract vll 15 music and the chemical elements. M. H. Doolittle. Abstract vll 26, 27 an attempt at a theory of odor. F. W. Clarke. Abstract vlll 27 Chickering, J. W., communication on the correlation of the winds and the tem- peratures of the surface waters of tho ocean along the coast of New Hamp- shire. Abstract 11 17 Luray cave. Title only Ill 65 Roan Mountain, N. C. In full Iv 60 the thermal belts of North Carolina. Ab- stract vl 11 the Muir glacier, Alaska. Title only...s. 15 Chesapeake and Ohio Railroad, Geology along 11(26) Chesapeake Bay geology x 16 Chico group in Northern California Ix 4 Chimsera, New species of 11 182 Chinese language 11 28 Chitonidse 11 193 Chlamydoconcha Orcuttl vlll 5 Chorography x 14 Christie, A. S., communication on a system of standard time. Abstract v 112 a quasi general differentiation. Title only vl 122 contact of plane curves. Abstract vl 157 a form of the multinomial theorem. Title only vli 101 a problem in probabilities. Abstract...x 89 remark on infinitesimals vl 135 Christmas eve meteor 11 139 Chronograph readings, Relative frequency of digits in 1 85 Circle, Quadrature of 1 57 Circles related to Feuerbach's circle vlll 45 Circular on the meteor of Dec. 24, 1873 11 139 Circumference, Ratio of, to diameter 1 57 Clark, Alvan, communication on the con- struction of the lenses and other inter- esting portions of the large telescope now established at the Naval Observa- tory. Title only 1 92 INDEX TO VOLUMES I-X. 129 Page. Clarke, F. W., communication on the atomic volumes of crystallized and double salts. Reference 1 103 the molecular heats of similar com- pounds. Abstract i 104 the periodic law of the elements. Ab- stract vll 15 topaz from Stoneham, Maine. Abstract and reference viii 5 an attempt at a theory of odor. Ab- stract vlii 27 the Flood Rock explosion. AbstracL.xill 28 the present status of mineralogy. Title only X 6 the Manchester meeting of the British Association for the Advancement of Science, 1887. Title only x 19 remarks on chemical theories of volean- ism vi 93 Classification of insectivorous mammals ...v 118 literature of meteorology x 26 plants iv 108 Clausen, cited on computation of 7r i 58 Clausius' researches in molecular physics, v 138, 140 Clerk-Maxwell. See Maxwell. Clifford's philosophy vii liii Climate and variations in solar radiation..vi 10 of plants ii 183 of Roan Mountain iv 62 Quaternary, of the Great Basin v 21 Climatic influence of land areas '....ii 46 Clingman, T. L., communication on the earthquake phenomena recently ex- perienced in Nerth Carolina. Abstract and reference i 104 the falling of waterspouts in North Caro- lina. Abstract ii 104 Cloud bursts in North Carolina ii 104 Coal, Formation of vi 28 Coastal plains ix 23 Coffin, J. H. C, cited on cyclonic motion...! 108 communication on maps prepared by G. W. Hill for use in connection with the transit of Venus in December, 1874. Reference i 63 Sumner's method in navigation. In full ii 105 remarks on calendars ii 29, 60 standard time ii 202, v 115 Cohesion v 127 and adhesion v 136 Coin, Amount of subsidiary silver ix 14 Coinage, International iil 38 of the Argentine Republic ii 65 Coincidences x 8 55 Page. Coins, Exhibition of. v 22 Collier, Peter, communication on sugar from sorghum. Abstract* iii 140 Color of Indians H 175 perception and color blindness iv 54 tests ill 54 Colorado of the West, Valley of the i 48 Coloring agent of gems ii 31 Columnar structure in the diabase of Orange Mt.. N. J viii 19 Comet, Barnard's- viii 17 Encke's i 34, 35 1, 1871, Elements of. i 23 III, 1884, (Wolf 's) viii 37 Orbit of Swift's iv 59 orbits illustrated by models x 28 Spectrum of Encke's.. i 34 Tuttle's i 34 Comets and meteors I 94 Comet's orbit, Correction of. il 22 Comets' tails i 74 r.ommittee, auditing, Appointment of...v 84, 174, vi 111, vii 82, viii 31, ix 47, x 39. Report of....v 89, vi 5, vii 15, viii 3, ix 3, x 3. Resolution on v 84 on communications i 21, ii viii, 101, iii 151, iv 31, 39, v 14, 175, vi xiv, xv, vii xiv, xv, viii xiv, xv, ix xiv, xv, x xiv, xv. on mathematical papers vi 135, 161, vii 129, viii 63, x 111 on mathematical papers, Resolution on..vi 135 on the meteor of December 24, 1873 i 94, 98, ii 139 on papers and essays. See Committee on Com- munications. on publications i 21, ii viii, 161, iii 151, v 14, 175, vi xiv, xv, vii xiv, xv, viii xiv, xv, ix xiv, xv, x xiv, xv. to draft resolutions on the death of L. Agassiz i 93, 94 F. B. Meek ii m A. B. Eaton ii m C. H. Davis ii m T. Bailey ., ...ii m J. Henry ii 196 A. R. Marvine ii 83 B. Peirce iv 21, 23 A. J. Myer iv 23, 31 G. A. Otis iv 120, 134 to draft resolutions on the discovery of the satellites of Mars ii 186 to nominate officers of Mathematical Sec- tion x 83 Communications, List of. See Acoustics, Anatomy, Anthropology, Archaeology, Astronomy, Biography, Biology, Botany, 130 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Calendars, Chemistry, Electricity, Geog- raphy, Geology, Mathematics, Meteor- ology, Microscopy, Mineralogy, Miscella- neous, Oceanography, Optics, Physics, Political Economy, Psychology, Seis- mology, Social Science, Thermometry, Zoology. Statistics of. x 32 Compass plant v 100 Composite photography applied to crani- ology vll 25 Composition of error v 100 Computation by method of least squares 1 02, vt 150, vill 41 of a comet's orbit 11 22 planetary perturbations of the moon vl 130 Computing the position of a satellite vll y:i machine jt 102 Comte, AugUtte, cited on forces v 127 Conditioned observations, Adjustment of, vlll 41 Conservation of energy vll 02 foreo i 27 Conservative element in disease It 111, 124 Consolidated list x 30 Constant Pin terrestrial magnetism x 102 Constitution. ..1 xv, It iii, lit iii, lv 5, v 0, vl vii, -vit vii, vttl vii, lx vii, x vii Adoption of t 80, 21 Amendment to tx 47, x :i9 Contact of plane curves vl 167 Contraction hypothesis vl 90, vlll 18 Corona of the sun 1 81, 111 116, 121 Corrections to normal thermometers lx 28 Corrigenda. ..11 p. 4 of cover. HI 148, vl 102, x 114 Coseismal map lx 39 Cosmos assembly hall x xxxi, 10, 31 Cosmos Club, Organization of x 47 Cotes, Roger, cited on ultimate causes v 163 Coues, Elliott, cited on Halrd's "Birds of North America" x 66 poisoned wounds from arrows 11 182 communication on the structure and homologies of the limbs, especially in Aves. Title only 1 90 the use of poisoned arrows by North American Indians. Title only 11 183 the possibilities of protoplasm. Abstract and reference 102 remarks on poisoned arrows 11 183 Counting-out rhymes x 13 Cracks in ice on Lake Champlaln 11 (22) Craig, B. F., communication on the fluctua- tions of the temperature of the human body. Reference 1 31 Page Craig, n. F., communication on—Cont'd, apothecaries' weights and measures. Title only 1 34 thermometers. Title only 1 42 a method of verifying with exactness the indications of a thermometer. Title only 1 43 apparatus for the generation of ozone. No abstract 1 62 the water supply of cities. Title only...i 65 Resolutions on J,he death of. 11 130 Craig, Thomas, communication on vortex motion in ordinary fluids. Reference, 111 143 Crane, C. H., Death of. vl 41 Cranlology vll 25 Crello. Dr. A. L., cited on Malfatti's prob- lem II 115 Croll, Prof. J., cited on action at a distance v 156 Croll's theory 11 43, 45 Crookes, W., cited on matter v 129 Crookos' radiometer 11 80 Cross Timbers of Texas x 6 Crumpling of the earth's crust vlll 18 Crystalline state of matter Ill 39 Culture media vlll 30 Cumberland plateau lx 24 Currents shown by drifting buoys vll 14 Curtis, G. K., communication on tho rela- tions between northers and magnotic disturbances at Havana. Reference, vll 25 Lieutenant Lockwood's expedition to farthest north. Abstract lx 8 the theory of the wind-vane. Refer- ence x 9 a problem in probabilities. No ab. itract x 88 solutions of the trisection problem. Ab- stract x 98 remarks on verification of weather pre- dictions vlll 9 Curtis, Josiah, letter on Hayden's Survey. Communicated by E. B. Elliott. No ab- stract 1 03 Death of. vl 41 Curve of tho fourth degree 1 30 Curves, Alignment t vl 123 Contact of plane vl 157 similar to their evolutes vll 87 Customs of every day life lx 19 Cutts, R. D., communication on the misap- plication of geographical terms, as bearing especially on .the question of the fishery right treaties. Abstract. ..I 39 INDEX TO VOLUMES I-X. 131 Page. Cutts, R. D., communication on—Cont'd, the results of astronomical observations at Sherman Station, Wyoming Terr. Abstract and reference i 70 the action of the International Geodetic Association as to an initial meridian and universal time. Abstract vi 106 Death of vi 111 Cyclones, Movement of 1 99 Retardation of v 108 Cyclonic storms, Laws of. 1 106 Dakota, Black Hills of. ill 125 calendar il 90 Dall.W. H., communication on the relative value of Alaska to the United States, as compared with that of other territorial acquisitions. Abstract and reference..X 25 elevations and depressions in Alaska. No abstract 11 27 the succession of the strata of the shell heaps of the Aleutian islands. Ab- stract 11 65 the results of recent investigations into the natural history of the Chitonida9. Abstract 11 193 the museums and zoological gardens of Northern Europe. Title only ill 19, 21 the muscles of the oyster. Abstract. ..Ill 36 the deep sea dredgings in the Gulf of Mexico and the West Indies in 1873- 1878, by Professors Louis and Alex- ander Agassiz and the officers of the U. S. Coast Survey. Title only ill 45 some recent observations on mollusks. Abstract Ill 75 the boundary line between Alaska and British America. Title only ill 77 recent discoveries in Alaska north of Behring Strait. Abstract iv 163 some peculiar features of mollusks found at great depths. Abstract .v 90 glaciation in Alaska. Abstract vi 33 recent advances in our knowledge of the limpets. Abstract vii 4 certain appendages of the mollusca. Reference vii 32 What is a glacier? Abstract vll 38 two remarkable forms of mollusks. Ab- stract and reference viii 5 South Florida notes. Title only x 16 Professor Baird in science. In full x 61 remarks on the glacial period 11 36 Arctic tides 11 89 teredo borings v 98 glaciation and climate vl 11 Page. Dall, W. H., remarks on—Cont'd. tornadoes vii 3 drifting buoys vii 15 deflection of rivers vll 21 the Bogosloff eruption vii 34 Arctic exploration ix 12 Dalton's atomic philosophy vii xlvii law v 139 Dana, J. D., cited on mineralogy i 78, 79 Darton, N. H., communication on the occur- rence of copper ore in the Trias of the Eastern United States. 'Title only...ix 46 Darwin's doctrine of gemmules vii liii law of the distribution of volcanoes. ...vi 89, 91 Dase, cited on computation of" 1 58 Davidson, George, letter on transit of Venus, 1874. Communicated by Asaph Hall. Abstract 11 32 Davidson, Lieut., cited on the co-ordinates of Bald Head, Alaska iv 126 Davis, C. H., Death of ii 111 Dawson, Prof. J. W., cited on fossil plants from Virginia ii (38), (42) Deaf mutes, Fallacies concerning vi 48 Languages of iv 55 Death of L. Agassiz 1 93 B. Alvord vii 72, 127 O. E. Babcock vii 72 S. F. Baird x 17, 20 43, 76 T. Bailey ii 109, 111 H. W. Blair vii 81 H. Capron vlii 8 S. P. Chase i 87 B. F. Craig ii 130 C. H.Crane vi 41 J. Curtis vi 41 R. D. Cutts vi 111 C. H. Davis il 111 A. B.Eaton ii ill E. Foote vl 48 L. D. Gale vi 48 W. B. Hazen x 6 J. Henry ii 19G, 203, 214, 358, 370 Mrs. J. Henry v 97 F. B. Hough viii 25 A. A. Humphreys vii 3, 4 F. Kampff. _ ii 1S9 W. C. Kerr viii 25 J. H. Lane Hi 122 E. P. Lull x 8 A. R. Marvine ii 83, (53) F. B. Meek ii m A. J. Myer iv 23, 31 G. A. Otis lv 120, 134, 171 T. R. Peale viii 10 B. Peirce lv 21, 23 132 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Death of—Cont'd. J. C. Riley lii 28 J. Rodgers v 102 B. F. Sands vi 41 G. C. Shaeffer i 00 W. J. Twining v 102 J. J. Woodward vll 72, 75 M. Yarnall ill 28 Declination standards ix 53 Deep sea mollusks v 90 Definitions y vli 46 Degradation. See Erosion. Delgarno, G., cited on instruction of the dumb vi 71 Delta of the Mississippi river i (10) Democritus' philosophy vii xxxiv Denihilo nihil fit vii xxx, xxxiii Denver, Altitude of 11 24 Department of science ix xlvi Depauperation of Limnsea Ill 75 Derham, Dr. W., cited on echoes v 41 De Tocqueville, cited on destruction of In- dians 11 175 Device for viewing the sun by light of any desired wave length x 13 Devonian strata near Sulphur Springs, W. Va 11(27) Dewar, Prof., cited on the radiometer 11 81 Diagnosis of blood-stains 11 20, 41 Diarrhoeal diseases and weather Iv 165 Diatonic scale vll 26 Differential equations admitting periodic integrals x 100 Diffraction fringes Ill 119 phenomena in the field of the micro- scope 11 60 Diller, J.S., communication on the volcanic sand which fell at Unalashka October 20, 1883, and some considerations con- cerning its composition. Abstract.-vii 33 topaz from Stoneham, Maine. Abstract and reference Till 5 the Keology of northern California. Ab- stract lx 4 the latest volcanic eruption in northern California and its peculiar lava. Refer- ence lx 46 Mount Shasta contrasted with Mount Rainier. No abstract x 11 remarks on geology of Cascade Moun- tains lx 8 Krakatoan dust vll 35 Diorthode vi 123 Diptheria, Inoculation of iv 38 Direction of sound, Determination of ill 69, viil 12, lx 43 Page. Discontinuity in elliptig orbits vii 122 Discovery of the satellites of Mars.... 11 186 Disease and climate Iv 165 Conservative element in ii 111, 124 Disinfection by gases iv 38 of ships lii 51 Dismal Swamp, Geology of. vi 28 Displacement, Geologic ii 75 of the middlo Atlantic slope .x 16 Dissipation of energy vll 63 Distances on any spheroid vili 52 Distribution of fossil plants x 28 mammals ii 26 scientific men and institutions x 7 the surplus money of the United States among the States vi 103 District of Columbia, Flora of iv 64 Diurnal variation of magnetic declination, ill 46 Dixwell, G. B., communication on cylinder condensation, steam jackets, and su- perheated steam. Title only Ii 64 Doane, G. C, report of the Yellowstone ex- pedition of 1870. Communicated by S. F. Baird. Reference i 21 Dobson, Surgeon-Major, cited on insectivor- ous mammals v 118, 120 Dog, Malformed ii 185 Doolittle, M. H., communication on the neb- ular hypothesis and the inner moon of Mars. Abstract ii 188, 190 the influence of aerolites on planetary motion. Abstract 11 190 aerolithic disturbance of planetary mo- tions. Abstract.. ii 190 a pile of balls. Abstract Ill 76 the silver question. Abstract Hi 103, 112 the geometrical problem to determine a circle equally distant from four points. Abstract v 88 substance, matter, motion, and force. Title only vi 14 infinite and infinitesimal quantities. Abstract vi 133 the rejection of doubtful observations. Abstract vi 152 music and the chemical elements. Abstract vii 26, 27 the verification of predictions. Ab- stract vii 122 cause and chance in the concurrence of phenomena. Title only viil 54 What is topography ? Abstract x 14 Newton's vis. Title only x 38 association ratios. Abstrlbt x 83 a problem in probabilities. Abstract. ..x 88 INDEX TO VOLUMES I-X. 133 Page. Dooliltle, M. H., communication on—Cont'd. association ratios. Abstract X93, 94 remarks on sesquisection Till 52 gravitation formula Till 40 phonetic alphabet ix 19 bi-metallism Ill 103 the need of abiomeier v 105 binary arithmetic vi 39 Dorsey, J. Owen, communication on the gentile system of the Omahas. In full. 3 figures Ill 128 Drainage system and loess of eastern Iowa, vl 93 of the Black Hills ill 125 systems 1 49 Draper, Prof. J. W., cited on photography. ..1 47 radiant energy v 135 Dreams in their relation with psychology..vi 37 Driftless region. vl 94 Drift of Iowa and Nebraska lv 120 Dry painting of the Navajos viil 14 Duane, Gen., cited on fog signals v 32, 43 phenomena of sound 11 (49), (50) Du Bois-Raymond, Experiments in animal electricity by v 57, 00, 01, 62 Dudley, P. II., communication on the uses of the dynagraph, and the work per- formed in determining the resistance of trains, etc. Abstract Ill 29 Dulong and Petit, Law of v 139 Thermometric experiments of. v 91, 93 Dumbness of deaf children vl 48 Du Pr6, Warren, cited on earthquakes 1 101 Dutton, C. E., communication on the meas- urement of the pressure developed by the explosion of gunpowder in fire- arms. Title only 1 52 some recent experiments on different kinds of gunpowder at Fortress Mon- roe. Titleonly 1 54 the causes of the elevations and subsi- dences of the earth's surface. Title only... 1 74 geological time. Titleonly 1 89 Mallet's theory of the formation of the physical features of the earth. Title only 1 90 recent improvements in the economy of fuel. Titleonly i 96 recent improvements in the manufac- ture of steel. Titleonly 1 97 the chemistry of the Bessemer process. Title only.„ 1 98 the glacial period. Titleonly 11 26 the causes of glacial climate. Abstract, 1143,45 | Page. Dutton, C. E., communication on—Cont'd, the geological character of the Colorado river. Titleonly Ill 28 the succession of volcanic eruptions. Title only ill 36, 37 the Permian formation of North Amer- ica. Abstract Ill 65, 67 the silver question. In full Ill 78 the scenery of the Grand Canon district. Title only lv 120 the Vermilion cliffs and the valley of the Virgen in southern Utah. C. E. Dutton. Titleonly lv 122 the geology of the Hawaiian islands. Abstract vl 13 the volcanic problem stated. Abstract, vl 87 What is a glacier ? Abstract vli 39 the volcanoes and lava fields of New Mexico. Abstract vil 76 practical geology versus speculative physics. Titleonly viil 4, 5 a recent visit to the scene of the Charles- ton earthquake and resulting conclu- sions. Titleonly x 16 the depth of earthquake foci. Abstract. 1 figure x 17 the speed of propagation of the Charles- ton earthquake. Reference x 28 remarks on distribution of volcanic ac- tion 1 102 wind and temperature observations 11 18 refraction of sound ii 58 geology of the Colorado region ii 76 the earth's interior ii 77 charcoal in the drift iv 122 separation of minerals by density vl 27 nebular hypothesis vi 45 temperature observation vl 48 outlines of continents vli 24 sun glows vli 35 Indian observation of nature vli 74 earthquake detonations viil 28 Charleston earthquake ix 42 Dynagraph, The iii 29 Dynamic hypothesis vi xxx theories of force v 126 Eastman, J. E., cited on individual vocabu- laries *i(21) communication on a comparison of the thermometers used to determine the correction for atmospheric refraction at the U. S. Naval Observatory. Ab- stract i 68 134 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Eastman, J. R., communication on—Cont'd, the frequency of the occurrence of the zero and the nine digits in the tenths of seconds as obtained from the chro- nograph ic record of transit observa- tions. Abstract i 85 the comparison of rain-gauges at differ- ent, elevations. Abstract ii 49 a personal equation instrument. Ab- stract ill 33, 37 some results from the discussion of the observations of the transit of Mercury of May 6, 1878. Abstract iii 43 the Florida expedition for observation of the transit of Venus [1882]. Ab- stract vi 21 the Rochester (Minnesota) tornado. Ab- stract vii 3 a new meteorite. Abstract vii 32 remarks on vocabularies 11 28 Eaton, A. B., communication on the preser- vation of foods. Title only 1 22 Death of 11 111 Eaton, Prof., cited on classification of ferns, lv 110 Earth, Interior of. 11 76 tremors as shown by astronomical obser- vations..... Ill 120 at Niagara Falls lv 186 Velocity of vill 28 Earthquake. See Seismology. Earth's crust, Crumpling of vili 18 interior, Condition of viil 7 Easter, Computation of vi 15 Echo from surface of ocean 11 171 Echoes, Tyndall on , v 41 Eclipse of the moon, June 11, 1881 v 90 sun, January 11, 1880 iii 121 sun, July 29, 1878 11 202, ill 116 Economic phase of the English sparrow question x 16 Economics. See Political Economy. Education in Japan 11 69 Edwards, W. H., cited on the pupation of the Nymphalidoe iii 42 Eidocenter viii 47 Eimbeck, Wm., cited on the diorthode vi 132 Elasticity v 130 Election of officers 1 20, 32, 64, 91, 11 16, 59, 86, 161, iii 17, 51, iv 29, v 84, 174, vi 111 vii 81, vill 80, ix 47, x 39. officers of the Mathematical Section...vi 122, vil 87, vili 37, lx 53, x 83 Electric receivers iv 153 researches by Joseph Henry ii 236 Electricity as a primitive force v 168 Page. Electricity, List of papers on (See also Acoustics) : on the recording systems of the trans- atlantic cables. J. E. Hilgard. Title only 1 53 [a method of lighting gas jets by electric- ity.] Dr. Van Sant. No abstract 1 56 on electricity engendered by the driving belt of the machinery for ventilating the Capitol at Washington. J. Henry. Abstract 11 40 Jablokoff' s electric candle. J. E. Hilgard. Title only ill 19 large area illumination by electricity. E. B.Elliott. Title only iii 45 the storage of electric energy. C. H. Koyl. Abstract v 46 units of force and energy, including elec- tric units. E. B. Elliott. Title only, vt 137 electric lighting. E. B. Elliott. Title only, vii 80 [exhibition of a volt-meter.] T. C. Men- denhall. Abstract vili 26 the electrometer as used in observation'* of atmospheric electricity. C. F. Mar- vin. Title only x 9 the mutual action of elements of electric currents. E. B. Elliott. Abstract and reference x 92 the quotients of space-directed lines. E. B. Elliott. Abstract x 105, 106 Elements, Periodic law of. vii 15 Elevation. See Altitude. Eliot and Storer, cited on atoms v 128 Elliott, E. B., calendar of the Society...vil xxii, vill xxx, lx xxvii, x xxxi: communication on the statistics of the borrowing power of the United States. Title only 1 29 the new coinage of Japan. Title only. ..I 31 the locus of the point of equal illumi- nation by two unequal lights treated by the quaternion analysis. Title only, i 35 the adjustment of census returns. Title only 1 63 life and annuity tables, based on the census of 1870. Title only i 74 international coinage. Title only 1 75 change in value of dollar. No abstract, I 91 the credit of the United States, as shown by the value of its securities. Title only 1 109 INDEX TO VOLUMES I-X. 135 Page. Elliott, E. B., communication on—Cont'd, the use of metric weights and balances for postal purposes in the United States. Abstract il 15 further remarks on metric weights and balances for the postal service. Ab- stract il 19 the transition in Germany, and the Scandinavian nations of Sweden, Nor- way, and Denmark, from the silver standard of coinage and money of ac- count to a gold standard 11 25 calendar formulae. Abstract 11 37 affected quantities of the first order. Title only 11 42 the mutual relations as to price of gold, silver bullion, silver coin, and green- backs. Title only 11 50 the mutual relation as to price of gold, greenbacks, silver bullion, and silver coin. Infull 11 52 adjustment of the calendar. Abstract..U 59 two propositions, now before Congress, for changing the coin of the United States. Title only 11 68 force and momentum. Title only 11 84 monetary standards. Title only 11 85 mutual relations of gold and silver, and of prices of commodities. Abstract...ii 87 the telephone. Title only il 111 a statistical diagram. No abstract 11 134 optional money standards. Title only...U 135 standards of time—international, sec- tional, and local. Abstract 11 137 the telephote. Abstract ii 192 musical intervals. Abstract ii 199 the adjustment of the Carlisle tables of reversions and annuities. Title only. .ii 201 meridional timo for railway and tele- graphic purposes. Abstract Ii 202 the progress of international coinage in France and America. Title only ill 27 the subject of international coinage. Abstract ill 38 large area illumination by electricity. Title only ill 45 the silver question. Abstract ill 103, 107 the construction of the Government sinking fund. Abstract ill 113 bi-metallism. Abstract iv 141 accrued interest on Government secur- ities. Title only v 21 the credit of the United States, past, present, and prospective. Title only..-v 102 some formulae relating to Government securities. Title only v 106 Page. Elliott, E. B., communication on—Cont'd, survivorships, with tables and formulas of construction. Title only v 122 formulas for the computation of Easter. In full vi 14 units of force and energy, including electric units. Title only vi 137 a financial problem. Title only vi 149 electric lighting. Title only vil 80 Benjamin Alvord. Infull vii 127 example illustrating the use of a certain symbol in the calculus of affected quantity. Title only viii 37 quantity of United States subsidiary sil- ver coin existing and in circulation. Title only ix 14 annual profit to banks of national bank note circulation. Title only ix 14 a problem in probabilities. No abstract, x 88 the mutual action of elements of elec- tric currents. Abstract and reference..x 92 a now computing machine. Abstract...x 102 the quotients of space-directed lines. Abstract x 105, 106 remarks on auroras i 45, iv 22 calendar reform ii 30 bi-metallism ill 103 Benjamin Peirce Iv 24 small loans by banks iv 34 the metric system vi 4 standard time vi 110 infinitesimals „ vi 135 theory of errors vi 148 tornado vii 3 sun glows vii 17 irrigation vii 20 Poole's euharmonic organ vii 28 Elliott, H. W., communication on the habits of the fur-bearing seals of the islands of St. Paul and St. George, Behring Sea. Reference 1 91 Elliptic integral of the third species Ix 54 integrals vil 102 Ellis, William, cited on the constant P x 102 Emmons, S. F., communication on ore de- position by replacement. Abstract and reference vl 32 What is a glacier? Abstract vii 37 remarks on glaciers vil 9 Emmons' Taconic system x 5 Encke's comet 134, 35 Endlich, F. M., communication on mineral systems. Infull 1 77 electrical phenomena in the Rocky Mountains. Title only 1 95 136 PHILOSOPHICAL SOCIETY OP WASHINGTON. Endlich, F. M., communication on—Cont'd, two bricks from the great wall of China. Title only i 98 specimens of meteoric iron from Chi- huahua, Mexico, and the structure of meteorites in general. Title only i 98 the occurrence of pure tellurium in cer- tain gold mines of Colorado. Title only 1 101 the coloring agent of gems. Abstract, 11 31 some interesting cases of metamor- phism. Title only Ill 27 remarks on the glacial period 11 36 Endowment of research viil xli Energy vll 61 Conservation and dissipation of 1 27 Engelman, Dr. G., cited on Quercus lv 110 English sparrow question x 16 Entomology. See Zoology. Eotvos, cited on sounds produced by me- teors .*..ll 157 Epicurus cited on philosophy vil xxx Erie, Altitude of Lake ~. 11 23 Erosion as related to displacement 11 75 by drifting sand 1 57 Errata 11 p. 4 of cover, 111 148, vi 162, x 114 Errors, Composition of. v 106 respecting the North American Indians..ll 175 Theory of. vi 138, 152 Eruption, Latest, in Northern California, ix 46 Theories of. vi 87 Eskimo shell heaps 11 65 Estimation of manganese as pyrophosphate, 11 132 Ether, Hypothesis of an vi xxix Ethnology. See Anthropology. Eucalyptus on tho Roman campagna vl 36 Eulcr ignored by Am. Phil. Soc vili xxxvii Euler's theorem — x 101 Eulogy on A. D. Bache - 1 35 A. A. Humphreys vil 4 Evolutes vll 87 Evolution and phthisis 11 125 Methods of vl xxvii of the bow and arrow Ix 44 elements _ vll 16 Expansion and buckling of ice fields 11 (22) Experimentation 11 163, vll li Explosion at Flood Rock.., vlii 28 " Explosion" of meteor explained- —11 143 Exposure of thermometers...-- ...vi 46, vll 80 Eye, Optical defects of 1 22 Eyes, Apparatus for testing Ill 53 shining in the dark ......vll 13 Page. Falconidse, Natural arrangement of..... 11 41 Fall line T ix 23 Fallacies concerning the deaf vi 48 Fallacy as to the theory of gravitation v 85 Faraday, cited on matter vll 48 Farquhar, Edward, cited on personal vocab- ulary. 11(18) communication on certain remarkable effects of lightning. Read by Joseph Henry. Titleonly 1 42 dreams in their relation with psychol- ogy. Abstract vi 37 remarks on the aurora iv 22 tornadoes vii 3 thunder storms vili 11 determining the direction of sound..vili 13 Farquhar, Henry, communication on exper- iments in binary arithmetic. Abstract, v 125, vi 3 further experiments in binary arith- metic. Abstract vi 38 form of least-square computation. In full vi 150 the problem discussed by Mr. Alvord. Abstract* vi 152 the theoretical discussion in Prof. P. G. Tait's "Encyclopedia Britannica" article on mechanics. Abstract vii 29 empirical formulae for the diminution of amplitude of a freely-oscillating pendulum. Abstract vil 89 a Fonetic jElfabet. Abstract ix 17 a comparison of the Boss and Auwers declination standards. Abstract and reference Ix 53 a problem in probabilities. Abstract. ..x 88 a solution and generalization of a prob- lem requiring the division of a rec- tangle into parts which form a square. No abstract x 96 remarks on standard time .v 114 infinitesimals- vi 135 drifting buoys vii 15 earth tremors vili 28 Fault at the base of the Wasatch Moun- tains 11 105 near Harper's Ferry vl 30 scarps 11 195 Faults, Geologic 1175,76 In the Sierra Nevada- ix 4, 5 of the Great Basin ix 5 Ferguson, J., observation of supposed trans- Neptunian planet ill 20 Ferrel, William, cited on deflection of rivers by rotation- vll 22 law of storms- l 100 INDEX TO VOLUMES I-X. 137 Ferrel, William, cited on—Cont'd. thermometry vi 25 communication on the effects of winds and barometric pressure on the tides of Boston, and on the mean level of the sea. Abstract and reference i 53 the law connecting the velocity and di- rection of the wind with the baro- metric gradient. Abstract i 106 the conditions determining tempera- ture. In full v90, 91 solar radiation at Sherman, Wyoming. Title only v 101 Feuerbach's circle viii 45 Finance. See Political Economy. Financial problem vi 149 Fish, Decrease of, on the southern coast of New England i 52 fauna of Massachusetts 1 29 New species of ii 182 Remarkable ingestion of. ill 116 Fishes, Shoulder girdle of i 64 Fisheries exhibitions Til 26, x 56 of the world v 117 Fishery Commission's work x 52, 69 right treaties, Interpretation of 1 39 Fletcher, Robert, communication on recent experiments on serpent venom. Ref- erence vi 38 report as treasurer vi! 82, viii xxviii, 31, lx xxx, 47, x xxxiv, 39 Fletchers and bowyers lx 44 Flexures of transit instruments vill 27 Flint, A. S., communication on the most probable value of the latitude and its theoretical weight from entangled ob- servations occurring in the use of Tal- cott's method. Abstract x 91 Flora of Laramie group viii 17 Roan Mountain iv 63 Washington and vicinity iv 64 Floras of America and Japan ii 42 different regions compared iv 99 Florida expedition for observation of the transit of Venus vi 21 Submergence of iv 53 Flood Rock explosion viii 28 Focal lines in astigmatism vi 45 Fog signals and acoustics...„ii 37, 57, 60, 167, 345, (45), iv 135, v 23, 39 Food adulteration iv 39 Foote, Elisha, communication on the laws of condensation of aqueous vapor in the atmosphere. Titltonly 1 74 a proposed method of observing astro- nomical transits. Title only 1 75 Page. Foote, Elisha, communication on—Cont'd, some causes that produce rain. Title only i 98 the causes of electrical developments in thunder storms. Abstract ii 189 Death of. vi 48 Force i 27, v 126, vi xxviii, vli 47 and life v 57 matter vii 30 Forecasts, verification of viii 8 Formula for the length of a seconds-pendu- lum vii 101 Formulae for area of a plane triangle viii 37 diminution of pendulum swing vii 89 Fort Yukon, Determination of position of...i 22 Fossil plants, Distribution of x 28 from Alleghany Co.,Va ii (26) Fossils in aerolites v 66 Foster, M., cited on muscular contraction..v 60 nerve currents v 62 Fourier, cited on the temperature of space..ii 73 Forshey, C. G., communication on the allu- vial basin of the Mississippi river styled the delta. In full i 9S, (10) Frank, F., cited on brain temperatures v 76 Franklin's scientific work viii xxxv Free will iv 46 Fremont, Dr. H. F., Researches on inocula- tion of diptheria by iv 38 Frisby, E., communication on a series for the determination of the number ex- pressing the ratio of the circumfer- ence to the diameter. In full i 57 a Gregorian calendar. Abstract i 75 series. Title only ii 193 the total solar eclipse of January 11th, 1880. Abstract Hi 121 magic squares. Abstract. § figures ...Hi. \4Z the orbit of Swift's comet. Abstract...iv 59 remarks on calendars ii 38 Frost limits in North Carolina vi 11 Fundamental distance in thermometry. ...ix 27 Fungi, Microscopic i 42 Gale, L. D., communication on the cause and remedy of the potato rot. Title only i 97 the geology of the lignite formation, and on a hitherto undescribed de- posit discovered in 1834 in New York bay. Title only i 106 the failure of the wooden pavements of Washington City. Abstract ii 26 the climate of plants. Abstract ii 183 remarks on the bowlders of Long Island. .ii 27 Death of. vi 48 138 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Galen, cited on life v 51 Galileo, cited on Saturn's rings vi 44 Gallaudet, E. St., communication on uncon- scious cerebration. Title only ii 48 the international convention of the teachers of the deaf and dumb, at Milan. Abstract iv 55 remarks on gesture language and visible speech -ri 77 Gamgee, A., cited on muscular contrac- tion v59, 60 nerve currents v C2 Gardner, J. T., communication on the use of railroad levellings in determining ele- vations on the great lakes and rivers in the United States and in the Rocky Mountains. Abstract and referencc.il 23 Gases, Theory of. v 138 Gauss, cited on computation of t? i 59 Gauss' algorithm vii 102 method for computing variation of ele- ments of an orbit -%riil 41 transformation vii 110 Gay-Lussac, Law of v 139 Gems, Coloring agent of ii 31 General committee rules. See Standing Eules. Gentile system of the Omahas iii 128 Geographical distribution of mammals ii 26 terms and fishery treaties i 39 Geography, List of papers on (see also Oceanography and Seismology) : official report of the Yellowstone expedi- tion of 1870. G. C. Doane. Communi- cated by S. F. Baird. Reference i 21 [exhibition of map of the headwaters of the Yellowstone and Lewis rivers.] M. C.Meigs. No abstract 1 21 [geographical centre of the United States.] J. E. Hilgard. Abstract i 22 on the results of travels in Alaska and the determination of the position of Fort Yukon. C. W. Raymond. Communi- cated by T. L. Casey. Reference i 22 [exhibition of dust from Armenia.] T. Antisell. No abstract i 25 on the relative value of Alaska to the United States, as compared with that of other territorial acquisitions. \V. H. Dall. Abstract and reference i 25 on the distribution of the population of the United States. J. E. Hilgard. Title only i 29 on observations made on a journey to Cali- fornia. J.Henry. Title only i 31 Pago. Geography, List o£ papers on—Cont'd. on the westward movement of the popula- tion of the United States. J. E. Hil- gard. Reference i 35 on the misapplication of geographical terms, as bearing especially on the question of the fishery right treaties. R. D. Cutts. Abstract i 39 recent explorations in Syria under the auspices of the Palestine exploration fund. Prof. Porter. Title only i 54 on certain recent geological and geograph- ical researches in Arizona and Nevada. G.K.Gilbert. Abstract 1 64 [a visit to Egypt.] W. T. Sherman. No abstract i 63 on the fluctuations of the river Nile. J. Henry. Title only i 63 [letter on the Hayden Survey.] J. Curtis. Communicated by E. B. Elliott. No ab- stract 1 63 on some measurements of heights by a pocket aneroid. W. Harkness. Title only 1 64 [on the Goldschmidt aneroid barometer.] J. E. Hilgard. No abstract i 65 [travels in Turkey and the Caucasus.] W. T. Sherman. No abstract i 65 on the proceedings of the International Metrological Commission. J. E. Hil- gard. Title only i 68 on the habitability of the elevated plateaus of the West. B. Alvord. Title only.. .i 74 on the use of the canons of the Colorado for weighing the earth. G. K. Gilbert. Title only i 88 on the recent determination of the longi- tude between Paris and Greenwich. J. E. Hilgard. Title only 1 89 on some of the results of the Polaris North Pole Expedition. E. Bessels. Refer- ence i 92 a method of describing and locating with ease the approximate positions of geo- graphical regions. J. M. Toner. Title only 1 97 on two bricks from the great wall of China. F. M. Endlich. Title only i 98 on the alluvial basin of the Mississippi river styled the delta. C. G. Forshey. In full i 98 (10) on the use of railroad levellings in deter- mining elevations on the great lakes and rivers in the United States and in the Rocky Mountains. J. T. Gardner. Abstract and reference ii 23 INDEX TO VOLUMES I-X. 139 Page. Geography, List of papers on—Cont'd. on the geographical distribution of mam- mals. T.Gill. Abstract 11 26 on the movements caused in large ice- fields by expansion and contraction, as illustrative of the formation of anti- clinal and synclinal axes in geological formations. M. C. Meigs. In full. 4 figures 11 33, (22) on the Uintah Mountains. J. W. Powell. Title only 11 34 the results of a recent determination of the elevation of the Caspian and Aral seas. A. Woeikoff. Abstract 11 34 account of progress of tho International Metrical Commission. J. E. Hilgard. Title only 11 41 the measurement of a base-line for the primary triangulation of the United States Coast Survey near Atlanta, Georgia. J. E. Hilgard. Abstract and reference 11 50 the watershed of the Adirondack region. F. P. Judd. Abstract 11 67 [voyage of the U. S. S. Swatara.] W. Hark- ness. No abstract 11 68, 69 Japan. H. Capron. Title only 11 79 the Adirondack watershed. F. F. Judd. Abstract 11 82 the deviations of the plumb-line as deter- mined in the survey of the 49th paral- lel of latitude. F. V. Greene. Ab- stract and reference 11 82 [route for] the interoceanic canal through Nicaragua. E. P. Lull. Title only. ..11 83 [visit to Japan.] T. Antisell. No abstract, 11 84 the late English polar expedition. E. Bessels. Abstract 11 89 a special method of barometric hypsome- try. G. K. Gilbert. Abstract 11131 standard scales or measures of length. J. E. Hilgard. Abstract 11 136 a proposed new leveling instrument. G. K. Gilbert. Abstract 11 184 the recent history of Great Salt Lake. G. K.Gilbert. Abstract 11187 the lands of the arid region of the United States. J.W.Powell. Abstract 11 1S9 on the Eanab base-line, and a proposed new method of base measurement. G. K. Gilbert. Abstract Ill 34 the secular change in the magnetic decli- nation in the United States and at some foreign stations. C. A. Schott. Ab- stract Ill 45 Page- Geography, List of papers on—Cont'd. [Luray cave.] J. W. Chickering. Title Only Ill 65 on the boundary line between Alaska and British America. W. H. Dall. Title only Ill 77 a model of the basin of the Gulf of Mexico. J. E. Hilgard. Abstract lv 52 notes on Roan Mountain, North Carolina. J. W. Chickering. In full lv 60 the scenery of the Grand Cafion district. C. E. Dutton. Title only lv 120 the Vermilion Cliffs and the valley of the Virgen, in Southern Utah. C. E. Dut- ton. Title only lv 122 boundary line between Alaska and Siberia. M.Baker. In full. Map lv 123 recent discoveries in Alaska north of Behr- ing strait. W. H. Dall. Abstract lv 163 on barometric hypsometry. G. K. Gilbert. Reference v 48 alignment curves on any surface, with special application to the ellipsoid. C. H. Kummell. Abstract. 1 figure vl 123 graphic tables for computing altitudes from barometric data. G. K. Gilbert. Reference vi 136 the existing glaciers of the High Sierra of California. I. C. Russell. Abstract and reference, ^figures vil 5 some physical and economic features of the Upper Missouri system. L. F. Ward. Reference vll 20 the diversion of water courses by the rota- tion of the earth. G. K. Gilbert. Ab- stract and reference vll 21 What is a glacier ? Symposium. Ab- stract vll 37 a concrete problem in hydrostatics. G. K. Gilbert. Abstract vil 92 a formula for the length of a seconds- pendulum. G. W. Hill. Reference, vii 101 discussion of a concrete problem in hydro- statics proposed by Mr. G. K. Gilbert. R. S. Woodward. Title only vii 101 variations of latitude. A. Hall. Abstract and reference viii 10 distances on any spheroid. C. H. Kum- mell. Abstract and reference viii 52 some practical features of a field time de- termination with a meridian transit. R.S.Woodward. Abstract viii 55 Lieutenant Lockwood's expedition to farthest north. G. E. Curtis. Ab- stract lx 8 140 PHILOSOPHICAL SOCIETY OF WASHINGTON. Geography, List of papers on—Cont'd. on the changes of terrestrial level surfaces due to variations in distribution of superficial matter. R. S. Woodward. Reference lx 15 the physical-geographical divisions of the southeastern portion of the United States and their corresponding topo- graphical types. G. Thompson. Ab- stract lx 22 on the position and shape of the geoid as dependent on local masses. R. S. Woodward. Reference 1x53, 54 the topography and geology of the Cross Timbers of Texas. R. T. Hill. Read by W J McGee. Reference x 6 the topography and structure in the Bays Mountains, Tennessee. B.Willis Ref- erence x 7 development of a perspective map from a contour map. B. Willis. Title only. ..tc 9 [exhibition of a new plane table.] W. D. Johnson. No abstract x 9 Mt. Kainier and its glaciers. B. Willis. Abstract x 10 What is a topographical map? M. Baker. Abstract x 11 What is topography? Symposium. Ab- stract x 14 the Muir glacier, Alaska. J. W. Ohicker- ing. Title only x 15 South Florida notes. W. H. Dall. Title only x 16 the progress of science as exemplified in the art of weighing and measuring. W. Harkness. Presidential address. In full x xxxvii, 39 the most probable value of the latitude and its theoretical weight from entangled observations occurring in the use of Talcott's method. A. S. Flint, Ab- stract x 91 Geoidal deformation by local masses vil 92, 101, lx 15, 53 Geology, List of papers on. (See also Seis- mology.) remarks on the structural geology of the valley of the Colorado of the West. J. W. Powell. Abstract 1 48 on certain recent geological and geograph- ical researches in Arizona and Ne- vada. G. K. Gilbert, Abstract I 54 on sand sculpture in the West. G. K. Gil- bert. Abstract 1 57 descriptions of new species of fossil plants from Alleghany County,Virginia; with Pftge. Geology, List of papers on—Cont'd. some remarks on the rock seen along the Chesapeake and Ohio railroad, near the White Sulphur Springs of Greenbrier County,West Virginia. F. B. Meek. In full Iplates 162,11(20) on the causes of the elevations and sub- sidences of the earth's surface. C. E. Dutton. Title only „ 1 74 on the glacial epoch in Utah and Nevada. G. K. Gilbert. Abstract 1 84 on geological time. <'. E. Dutton. Title only 1 89 on Mallet's theory of the formation of the physical features of the earth. C. E. Dutton. Title only 1 90 on the recent earthquakes in North Caro- lina. B. Alvord. .Abstract 1 101 on a cold geyser or intermittent artesian well in Ohio. G.K.Gilbert. Abstract, t 103 on the geology of the lignite formation, and on a hitherto undescribed deposit discovered in 1831 in New York bay. L. D. Gale. Title only 1 106 on the age of the Ton to sand- tones. G. K. Gilbert. Abstract and reference 1 109 on the glacial period. C. E. Dutton. Title only 11 26 [geological history of Lake Winnipeg.] G. K. Warren. Abstract 11 27 [elevations and depressions in Alaska.] W. H. Dall. No abstract 11 27 on the movements caused in large ice- fields l>y expansion and contraction, as illustrative of the formation of anti- clinal and synclinal axes in geological formations. M. C. Meigs. In full. 4 figures 11 33, (22) on the Uintah Mountains. J.W.Powell. Titleonly 11 34 the glacial theory. J. Henry. Abstract. .11 35 the causes of glacial climate. Symposium. Abstract 1143, 45 ripple-marks. G. K. Gilbert. Abstract...11 61 some types of mountain building. J. W. Powell. Titleonly 11 65 landslips and lakelets. G.K.Gilbert. Ab- stract 11 69 monoclinal ridges. J. W. Powell. Ab- stract 11 74 the distribution of thermal springs in the United States. G. K. Gilbert. Title only «. 11 80 [geologists versus physicists.] J. W. Pow- ell. No abstract 11 85 INDEX TO VOLUMES I-X. 141 Geology, List of papers on—Cont'd. Lake Bonneville. G. K. Gilbert. Abstract and reference 11 103 the structure of the Henry Mountains. G. K. Gilbert. Abstract and reference, 11 112, 113 chemical remarks on terrestrial geogony. T. Antisell. Title only 11 132, 133, 134 the Wasatch a growing mountain. G. K. Gilbert. Abstract 11 195 on some interesting cases of metamorph- ism. F. M. Endlich. Title only Ill 27 the geological character of the Colorado river. C. E. Button. Title only Ill 28 the succession of volcanic eruptions. C. E. Dutton. Title only Ill 36, 37 on the Permian formation of North Amer- ica. C. E. Dutton. Abstract ill 65, 67 the subject of the Permian formation in North America. C. A. White. .46- stract Ill 104 on the oscillations of Lake Bonneville. G. K. Gilbert. Title only Ill 113 the drainage system of the Black Hills. G.K.Gilbert. Abstract Ill 125 quaternary deposits of western Iowa and eastern Nebraska. J. E. Todd. Ab- stract iv 120 the Vermilion cliffs and the valley of the Virgen in southern Utah. C. E. Dut- ton. Title only Iv 122 the origin of the topographical features of lake shores. G.K.Gilbert. Title only.iv 170 the quaternary climate of the Great Basin. G. K. Gilbert. Reference v 21 on artesian wells on the Great Plains. C. A. White. Reference v 101 geology of the Hawaiian islands. C. E. Dutton. Abstract vi 13 the geology of Hatteras and the neighbor- ing coast. W. C. Kerr. Abstract vl 28 topographical indications of a fault near Harper'* Ferry. H. F. Walling. Ab- stract vi 30 ore deposition by replacement. S. F. Em- mons. Abstract and reference vl 32 glaciation in Alaska. W. H. Dall. .46- stract vi 33 the volcanic problem, stated. C. E. Dut- ton. Abstract vi 87 the drainage system and the distribution of the loess of eastern Iowa. W J McGee. Abstract vi 93 the Cambrian system in the United States and Canada. C. D. Walcott. Abstract, lfigure vi 98 Page. Geology, List of papers on—Cont'd. the existing glaciers of the High Sierra of California. I. C. Russell. Abstract and reference. 2 figures vii i the mica mines of North Carolina. W. C. Kerr. Abstract vii 9 deposits of volcanic dust in the Great Basin. I. C. Russell. Abstract vii 18 the diversion of water courses by the rota- tion of the earth. G. K. Gilbert. Ab- stract and reference vii 21 the volcanic sand which fell at Unalashka October 20, 1883, and some considera- tions concerning its composition. J. S. Diller. Abstract vll 33 the methods of modern petrography. G. H. Williams. Abstract vll 36 What is a glacier? Symposium. Abstract, vii 37 the strata exposed in the east shaft of the water-works extension. T. Robinson. Abstract vii 69 plan for the subject bibliography of North American geologic literature. G. K. Gilbert. Title only vii 71 plan for the subject bibliography of North American geologic literature. J. W. Powell. Title only vll 71 the volcanoes and lava fields of New Mex- ico. C. E. Dutton. Abstract vii 76 a concrete problem in hydrostatics. G. K. Gilbert. Abstract vii 92 discussion of a concrete problem in hydro- statics proposed by Mr. G. K. Gilbert. R. S. Woodward. Title only vii 101 practical geology versus speculative phys- ics. C. E. Dutton. Title only viii 4, 5 geological and physical theories. W. B. Taylor. Abstract , vili 6 variations of latitude. A. Hall. Abstract and reference viii 10 the flora of the Laramie group. L. F. Ward. Reference vili 17 problems connected with the physics of the earth's crust. H. M. Paul. Title only viii 17, IS the crumpling of the earth's crust. W. B. Taylor. Abstract and reference viii 18 the columnar structure in the diabase of Orange Mountain, N. J. J. P. Iddings. Abstract. 4 figures viii 19 the terraces of the Potomac valley. W J McGee. Title only viii 24 notes on the geology of northern Califor- nia. J. S. Diller. Abstract ix 4 142 PHILOSOPHICAL SOCIETY OP WASHINGTON. Page. Geology, List of papers on—Cont'd. notes on the faults of the Great Basin and of the eastern base of the Sierra Ne- vada. I. C. Russell. Abstract Ix 5 recent changes of level in the basin of Lake Ontario. G. K. Gilbert. Refer- ence tx 8 on the changes of terrestrial level surfaces due to variations in distribution of superficial matter. R. S. Woodward. Reference ix 15 on tho observed changes of level surfaces in the Bonneville area, and their ex- planation. G. K. Gilbert. Title only, ix 15 on the varying attitudes of former level surfaces in the Great Lake region and the applicability (if proposed explana- tions. T. C. Ohamberlin. Title only..Ix. 15, 16 the enlargement of mineral fragments as a factor in rock alteration. R. D. Irv- ing. Title only ix 16 the stibaerial decay of rocks and the ori- gin of the red clay of certain forma- tions. I. C. Russell. Title only ix 1G on geological museums. G. P. Merrill. Titleonly ix 3G certain new and small mountain ranges. G. K. Gilbert. Title only ix 45 on the occurrence of copper ore in the Trias of the Eastern United States. N. H. Barton. Titleonly ix 46 the latest volcanic eruption in northern California and its peculiar lava. J. S. Diller. Reference ix 46 on the position and shape of the geoid as dependent on local masses. R. S. Woodward. Reference ix 53, 54 the geologic age of the lowest formation of Emmons' Taconic system. C. D. Wal- cott. Reference i x 5 the topography and geology of the Cross Timbers of Texas. R. T. Hill. Read by W J McGee. Reference x 6 the topography and structure in the Bays Mountains, Tennessee. It. Willis. Title only x 7 Mt. Rainier and its glaciers. B. Willis. Abstract x 10 [Mt. Shasta, contrasted with Mt. Rainier.] J. S. Diller. No abstract x 11 the Muir glacier, Alaska. J. W. Chicker- ing. Titleonly x 15 the quaternary deposits and tlie great dis- placement of the Middle Atlantic slope. W J McGee. Reference x 16 Page. Geology, List of papers on—Cont'd. South Florida notes. W. H. Dall. Title only x 10 on the geographical distribution of fossil plants. L. P. Ward. Reference x 28 Geometrical problems ill 55, 64, v 88, loT, vi 157, viii 4"> Geometry, Grassmann's viii 53 Germ culture i 42, viii 30 Gesture language vi 63,84 Geyser, A cold i 103 Gilbert, G. K., cited on wind and barometric observation v 108 verification of predictions vii 122, x 9t, 96 communication on certain recent geolog- ical and geographical researches in Arizona and Nevada. Abstract i 54 sand sculpture in the West. Abstract, 1 57 the glacial epoeh in Utah and Nevada. Abstrant 1 84 the use of the cations of ilio Colorado for weighing the earth. Titleonly i 88 a cold geyser or intermittent artesian well in Ohio. Abstract i 103 the age of tho Tonto sandstones. Ah stract and reference 1 109 ripple-marks. Abstract ii oi the horarv oscillations of the tempera- ture of the atmosphere. Abstract ii 07 horary oscillations of the atmosphere. Abstract ii 69. landslips and lakelets. Abstract ii 69 the distribution of thermal springs in the United States. Titleonly 11 80 Lake Bonneville. Abstract and refer- ence ii 103 the structure of the Henry Mountains. Abstract and reference ii 112, 113 a special method of barometric hyp- sometry. Abstract ii 131 a proposed new leveling instrument. Abstract ii 184 the recent history of Great Salt Lake. Abstract ii 187 the Wasatch a growing mountain. Ab- stract ii 195 the Kanab base-line, and a proposed new method of base measurement. Abstract...'. iii 34 air currents on mountain slopes. Ab- stract iii 38 the oscillations of Lake Bonneville. Titleonly ill U3 the drainage system of the Black Hills. Abstract iii 125 INDEX TO VOLUMES I-X. 143 Page. Gilbert, G. K., communication on—Cont'd, the origin of the topographical features of lake shores. Title only iv 170 the quaternary climate of the Great Basin. Reference v 21 barometric hypsometvy. Reference v 48 error? of barometric observations pro- duced by wind. Reference v 91 a graphic table for computation. Ab- stract v 120 the response of terrestrial climate to secular variations in solar radiation. Abstract vi 10 graphic tables for computing altitudes from barometric data. Reference vi 136 the diversion of water courses by the rotation of the earth. Abstract and reference vii 21 the subject bibliography of North Amer- ican geologic literature. Title only..vii 71 the problem of the knight's tour. Ab- stract vil 88 a concrete problem in hydrostatics. Ab- stract vii 92 recent changes of level in the basin of Lake Ontario. Reference ix 8 the observed changes of level surfaces in the Bonneville area, and their ex- planation. Title only ix 15 certain new and small mountain ranges. Title only ix 45 graphic methods in research. Abstract..*. 4 statistics of the Philosophical Society from its foundation Abstract x 29 remarks on vocabularies ii 28 fresh water shells in brackish water. ..ii 181 the Permian of Utah iii 105 artesian wells on the Plains v 101 drainage system of Iowa vi 97 origin of pumice vii 25 verification of predictions vii 127 terrestrial rigidity viii 7 care of pamphlets viii 29 geology of northern California ix 7 earthquake waves and sound waves, ix 43 Gilded thermometer bulbs ix 33 Gill, T. N., communication on the character- istics and zoological relations of man. Abstract i 24 additions to the fish fauna of Massachu- setts, due to the researches of Prof. S. F. Baird, U. S. Fish Commissioner. Reference i 29 the tapir of the Andes and its allied forms. Title only i 39 Page. Gill, T. N., communication on—Cont'd. a tunny new to the American coast. Title only i 47 the homologies of the shoulder girdle of fishes. References i 64 tbe Scombrocottus salmoneus of Peters. Title only ...i 68 the homologies of the arm in fishes, and the development of the humerus in ganoids. Title only I 73 the primates and their relations to man. Title only t 96 the structure and shape of Palaeothe- rium. Abstract i 99 the geographical distribution of mam- mals. Abstract ii 26 the causes of the glacial climate. Ab- stract ii 47 tho progress of the natural sciences dur- ing the past century. Reference ii 56 the relations and sequences of the family Centrarehoides. Title only ii 113 the morphology of the antlers of the Cervidse. Abstract and reference ii 135 a new species of Chimoera found in Amer- ican waters. Abstract ii 182 the family of Ceratiids. Title only ii 202 the Prodromus mcthodi mammalium of Storr. In full ii 15, (3) some remarkable instan ces of ingestion among fishes. Abstract iii 116 principles of morphology. Refcrcnce..W 123 the classification of the insectivorous mammals. In full v 118 analogues in zoo-geography. Title only, vi 41 ichthyological results of the voyage of the Albatross. Title only vi 48 remarks on the decrease of fish on the southern coast of New England i 62 vocabularies ii 28 Peruvian fishes ii 35 geological climates ii 36, 48 calendars ii 38 Dakota calendar ii 94 marine fishes in fresh waters ii 181 resemblances in biology ii 187 an occurrence of the tarpa ii 202 ravages by teredo v 98 vital force v 104 Glacial epoch, Cause of. ii 35, 43, 45 in Utah and Nevada i 84 Glaciation in Alaska vi 33 Glacier tables vii 7 What is a? vii 37 Glaciers of Alaska x 15 144 PHILOSOPHICAL SOCIETY OP WASHINGTON. Page. Glaciers of the High Sierra vii 6 Mt. Rainier x 10 Glaisher, cited on barometric gradient™ i 107 Gley, E., cited on the pulse v 78 Goethe, cited on appHed science vii 12 Gold and silver and the prices of commodi- ties i* 87 and silver coinage iii 78, 107 Gold-silver ratio iv 141 Goode, G. B., Bibliography of S. F. Baird by ..x 62 communication on the swordfish and its allies. Reference iv 162 the fisheries of the world. Reference...-? 117 fisheries exhibitions. Reference vii 26 the systematic care of pamphlets. Ab- stract and reference. viii 29 the distribution of fishes in the oceanic abysses and middle strata. Title only, ix 22 museum specimens illustrating biology. Title only ix 36 the geographical distribution of scien- tific men and institutions in the United States. Reference x 7 Goodfellow, E., remarks commemorative of Benjamin Peirce.„ iv 25 Gould, B. A., letters on Cordoba Observatory. Communicated by J. H. C. Coffin and J. J. Woodward. No abstract i 57 letter on Cordoba Observatory. Commu- nicated by J. J. Woodward. No ab- stract i 88 communication on scientific culture in the Argentine Republic. No abstract ii 15 the coinage of the Argentine Republic. Read by E. B. Elliott. Abstract ii 65 Governmental endowment of research...viii xli Graham, Law of v 138 Graphic methods in research x 4 table for computation v 120, vi 136 Grasshoppers, Shower of ii 87 Grassmann's system of geometry viii 53 Gravitation vii 43, 47 Fallacy concerning v 85 Modification of formula of viii 39 Gray, Asa, cited on the classification of plants iv 108, 109, 110 communication on plants common to Japan and eastern America. Ab- stract ii 42 Gray, Elisha, communication on a telaphon. Abstract ii 67 Gray, L. C, cited on brain temperatures....v 76 Great Basin, Fault3 of ix 5 Later geology of i 84 Page. Great Basin, Quaternary climate of. v 21 ranges, Bibliography of. ix 6 volcanic dust in vil 18 Great Salt Lake, Fluctuations of ii 187, 188 Great Spirit, The, a mistake 11 170 Grecian atomic philosophy vii xxix Greely, A. W., cited on bibliography of me- teorology Jt 22 Green, H. J., cited on thermometry ix 25 Greene, B. F., communication on the Navy compass. Title only ii 123 an adjustable binnacle for the correction of a ship's compass. Title only ii 134 Greene, F. V., communication on the devia- tions of the plumb-line as determined in the survey of the 49th parallel of latitude. Abstract and reference* ii 82 Gregorian calendar, A i 75 Proposed reformation of ii 29 Growth of stones and organisms v 67 Grunmach, Dr., cited on thermometry..ix 30, 32 Gudermann's notation vii 103 Gulf of Mexico, Model of. iv 52 Gulf stream, Channel of. iv 53 Gunnell, F. M., communication on yellow fever disinfection. Abstract iii 51 Guthrie, Prof. F.. cited on attraction v 150 Guyot, Arnold, cited on the Appalachians, iv 61 distribution of mountains and plains, viii 19 Habits of fur-bearing seals i 91 llahn, O., cited on fossils in aerolites v 66 Hall, Asaph, communication on the elements of the Comet I, 1871. Read by B. F. Sands. Abstract i 23 astronomical photography. Abstract and reference i 28 a curve of the fourth degree. Abstract and reference i 30 the astronomical proof of the existence of a resisting medium in space. Refer- ence i 34 an historical note on the method of least squares. Reference i 62 the experimental determination of the ratio of the circumference to the diameter, based on the principles of the calculus of probabilities. Title only i 62 the rectilinear motion of a particle toward an attracting centre. Refer- ence i 88 comets and meteors. Reference i 94 INDEX TO VOLUMES I-X. 145 Hall, Asaph, communication on—Cont'd. the method adopted in writing the in- ternational scientific telegrams. Ab- stract , i 101 the operations of the several parties sent from the United States to observe the transit of Venus on the 8th of Decem- ber, 1874. Abstract 1131,32 approximate quadratures. Abstract, 11 48 the appearance of Saturn's rings. Ab- stract 11 94 a bright spot which has recently become visible on the ball of Saturn. Ab- stract .11 102 the position of the centre of gravity of the apparent disk of a planet. Refer- ence 11 181 the results of a search for satellites of Mars. Abstract and reference 11 186 the supposed discovery of a trans-Nep- tunian planet at the U. S. Naval Ob- servatory in 1850. Abstract Ill 20 the satellites of Saturn. Abstract ill 26 the orbits of Titan and Hyperion. Ab- stract Ill 40 inaugural address as chairman of the Mathematical Section. In full vl 117 the determination of the mass of a planet from observation of two satel- lites. Abstract vl 132 the formulae for computing the position of a satellite. In full. 1 figure vil 93 American scientific societies. Presiden- tial address. In full viii xxxiii, 30 variations of latitude. Abstract and ref- erence viil 10 the new star in the nebula of Andro- meda. Reference ix 14 the images of stars. Reference ix 15 a problem in probabilites. Read by G. W.Hill. No abstract x 88 the parallax of a Tauri. Abstract x 91 Euler's theorem (generally called Lam- bert's). Abstract x 101 Longitude of Plover Bay by „lv 124, 126 remarks on planetary motions. ..11 188, 189, 192 transit of Mercury il 199 criteria for the rejection of observa- tions vl 155 Grassmann's geometry vlll 53 time determinations viil 58 Hall, G. S,, communication on recent expe- riments on reaction time and the time sense. Title only viil 4 Hallcr, A. von, cited on nerve currents. .....v 61 56 Page. Hallowell, Benjamin, letter on the meteor of December 24, 1873. Communicated by J. Henry. No abstract 1 95 Halo, A remarkable solar v 112 Hamilton, Sir W., cited on ultimate causes, v 163, 166 Harkness, William, communication on the physical constitution of the corona of the sun. Reference 1 31 the spectrum of Encke's comet. Refer- ence 1 34 the spectrum of Encke's comet, and the appearance of Tuttle's comet. Refer- ence 1 34 the density of the hypothetical resisting medium in space. Title and refer- ence 1 39 some measurements of heights by a pocket aneroid. Title only 1 64 the power necessary to drive the pendu- lum of an astronomical clock. Title only 1 74 the distribution of temperature over the surface of the globe. Reference 1 96 the apparatus to be used in the observa- tions of the approaching transit of Venus. Title only i 102 the transit of Venus in 1874. Communi- cated by A. Hall. Abstract 11 32 the methods of measuring the inequali- ties of the pivcts of the transit instru- ment. Title only 11 68 the voyage of the U. S. S. Swatara. No abstract 11 68, 69 the velocity of light and determination of the solar parallax. Title only 11 201 tho color corrections of achromatic ob- jectives. Abstract Ill 39 the number of lenses required in an . achromatic objective, consisting of in- finitely thin lenses in contact, in order that, with any given law of dispersion whatever, the greatest possible num- ber of light-rays of different degrees of refrangibility may be brought to a common focus. In full Hi 65 the solar corona. Abstract iii 116 the relative accuracy of different meth- ods of determining the solar parallax. Reference v 39 the monochromatic aberration of the human eye in aphakia. Reference, vi 5 flexures of transit instruments. Ab- stract viil 27 146 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Harkness, William, communication on—Cont'd, the progress of science as exemplified in the art of weighing and measuring. Presidential address. In /wK....x xxxvii, 39 a device for viewing the sun by light of any desired wave length. Abstract...x 13 the representation of comet orbits by models. Reference x 28 the constant P in observations of terres- trial magnetism x 102 remarks on the black drop 11 199 results from photographs of the transit of Venus lv 169 vital force v 105 temperature observations vl 26 hygrometry vl 36 postulated continents vl 93 accidental and constant errors vl 133 glaciers vii 9 vision vll 13 problem in probabilities x 89 Harper's Ferry, Fault near vl 30 Hart, A. S., cited on Malfatti's problem..ll 117, 119 Harting, cited on mineral aggregates ill 39 Hartley, J., Solution of a geometrical prob- lem by Ill 64 Hatteras, Geology of Cape vl 28 Hausen, C. A., cited on nerve currents v 60 Hauy, cited on mineralogy 1 77, 78 Havana magnetic disturbance and north- ers vil 25 Hawaiian geology vl 13 Hayden, Everett, communication on the Charleston earthquake. Abstract. Map lx 38 Hayden, F. V., cited on base-line methods.JU 34 Hazen, H. A., communication on tho retarda- tion of storm centres at elevated sta- tions and high wind as a probable cause. In full v 108 the coming winter of 1882-'83. Ab- stract v 122 hygrometric observations. Abstract...-vi 36 thermometer exposure. Abstract vl 46 the sun glows. Abstractand reference..vil 17 thermometer exposure. Abstract. ....vll 80 thunderstorms of 1884. Abstract viii 10 the condensing hygrometer and sling psychrometer. Abstract viil 25 effects of solar radiation upon thermom- eter bulbs having different metallic coverings. Abstract ;.lx 33 the sky glows of 1883. Title only x 6 relation between wind velocity and pressure. Reference ~ x 10 remarks on deflection of rivers vll 24 Page. Hazen, H. A., remarks, on—Cont'd. . weather prediction vill 9 care of pamphlets _ viii 29 graphics _ x 5 wind vanes x 9 the sparrow question x 16 Hazen, W. B., bibliography of meteorology x 21 Death of .. x 6 Heat of the sun 1 31 Theory of v 133 Heats, Molecular 1 104 Hell Gate explosion viii 28 Hellmann, Dr. G., bibliographic work in meteorology x 20, 21, 23, 25 Helmert cited on alignment curves....vl 124, 126 Henry, Joseph, Address on the life and char- acter of li 203, 368, 370 cited on a telephonic experiment ii 104 adhesion and cohesion v 137 land and sea breezes v 29 Bound anomalies li 58, iv 135, v 33, 40, 43 the Philosophical Society x 45 Washington as a scientific center x 47 communication on phenomena of sound and experiments with tuning forks. Title only„ 1 22 observations made ou a journey to Cali- fornia. Title only i 31 the organization and objects of the So- ciety. Presidential address. In full, lv,34 , the life and scientific labors of the late Alexander Dallas Bache. Reference. ..1 35 the expenditure of the income of the Bache fund for 1872. Title only i 53 the fluctuations of the river Nile. Title only 1 03 the condition of the Society. No ab- stract i 64 Bound in relation to fog-signals, from in- vestigations under the direction of the U. S. Light House Board. In full......t 65, li (45) atmospheric electricity. Title only.. ..I 75, 87 experiments on fog signals during the past summer. Title only i 90 a method of developing magnetism in barsofsteeL Title only 1 97 meteor trains, and the upper atmos- pheric currents. Tttleonly i 98 Giffard's injector. Title only ;i 99 audition. Title only„ 11 22 the glacial theory. Abttract _ 11 35 fog signals and abnormal conditions of sound. Reference li 37 INDEX TO VOLUMES I-X. 147 Page. Henry, Joseph, communication on—Cont'd. electricity engendered by the driving belt of the machinery for ventilating the Capitol at Washington. Abstract.M 40 sound in connection with fog signals. Reference ii 57 half-vision. Title only ii 60 researches on sound in its application to fog signals. Presidential address. Reference ii 60 illuminating materials. Title only ii 71 Crookes' radiometers. Abstract ii 80 [fog signals.] Abstract ii 85 paper made of asbestos. Title only ii 86 scientific method and its application to acoustic researches in connection with fog signals. Presidential address. In full ii 162 Memoir on the scientific work of ii 230 Memorial services of iii 27 Portrait of ii frontispiece- remarks on auroras i 46, 48 Japan ii 71 waterspouts ii 105 Resolutions on the deaih of ii 196 Henry, Mrs. Joseph, Death of v 97 Henry Mountains ii 113 Heraclitus, cited on philosophy vii xxxi Herapath, J., cited on elasticity v 130 Hering's theory of color iv 54 Hermann, cited on muscular contraction v 58, 59 nerve currents v 61 Hermaphrodite, Alleged i 24 Herschel, Sir John, cited on cohesion v 129 force v 151, 153 laws v 169 standard time v 115 satellites of Uranus i (30), (34) temperature of space ii 73 theory of errors vi 138, 140 Herschel, Sir William, cited on relation of light to heat v 135 satellites of Uranus i (30) Saturn ii 102 Saturn's rings vi 43 High-heeled shoes v 117 High power definition i 47 High Sierra glaciers vii 5 Hilgard, J. E., cited on earthquake tides...v 144 communication on the distance trav- ersed by approaching the North Pole on a loxodromic curve. Title only i 21 a chronograph. No abstract i 22 the geographical centre of the United States. Abstract i 22 Page. Hilgard, J. E., communication on—Cont'd. a chronoscope. No abstract i 23 the distribution of the population in the United States. Title only i 29 an exponential formula having reference to the tolerance allowed at the U. S. mint. Title only i 31 the westward movement of the popula- tion of the United States. Reference.,1 35 the aurora of February 4th. Abstract. ...i 47 Hindoo arithmetic. Title only i 53 the recording systems of the trans-At- lantic cables. Title only i 53 the Goldschmidt aneroid barometer. No abstract i 65 the proceedings of the International Metrological Commission. Title only 1 68 an inquiry into the law of probability. Title only i 84 the air thermometer of Prof. Jolly. Title only i 89 the recent determination of the longi- tudo between Paris and Greenwich. Title only i 89 recent experimental researches in acoustics, by Prof. A. M. Mayer. Title only i 90 the determination of the personal errors in the observation of astronomical transits. Title only i 92 a new apparatus for the investigation of personal error in astronomical transit observations. Title only i 106 a proposed reformation of the Gregorian calendar. Abstract ii 29, 30 the proceedings of the International Metrical Commission. Title only ii 41 iron facing copper plates. Abstract ii 42 the measurement of a base-line for the primary triangulation of the United States Coast Survey near Atlanta, Georgia. Abstract and reference ii 50 standard scales, or measures of length. Abstract ii 136 an optical salinometer. Abstract ii 185 Jablokoff's electric candle. Title only m 19 phosphorescent clocks. Abstract iii 33 remarks commemorative of Jonathan Homer Lane. In full iii 122 a model of the basin of the Gulf of Mex- ico. Abstract iv 52 Siemens' deep sea thermometer and Carr6's ice machine. Title only. v 100 remarks on auroras i 40, 43 148 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Hilgard, J. E., remarks on—Cont'd. persistent observation of phenomena..ii 19 vocabularies H 28 calendar reform H 30 photographs of the sun ii 33 cause of glacial climate 11 36 a new meteorological instrument il 64 Dakota calendar 11 92 Peirce's Linear Associative Algebra. ..lv 24 unification of longitudes and time vl 109 Hilgard, Theodore, communication on the number of the cepbalic vertebrae. Reference 1 26 Hill, G. W., communication on certain pos- sible abbreviations in the computation of the long-period perturbations of the moon's motion due to the direct action of the planets. Abstract and reference vl 136 a formula for the length of a seconds- pendulum. Reference vii 101 a problem in probabilities. Abstract. ..x 88 the motion of Hyperion. Abstract and reference x 90 the integration of differential equations admitting periodic integrals. Abstract and reference x 100 remarks on infinitesimals vl 135 gravitation formula vlil 40 adjustment of conditioned observations, viii 41 Grassmann's geometry vill 53 density of Mercury .viii 45 problem in probabilities x 89 electric currents x 93 Hill, M., cited on visible speech vi 78, 80 Hill, R.T., communication on the topography and geology of the Cross Timbers of Texas. Read by W JMcOee. Reference, x 6 Hillhouse, Dr. William, cited on trisection of angles x 99 Hind, cited on supposed trans-Neptunian planet ill 20 Historical note on binocular microscopes, iv 35 on the method of least squares .....1 62 History of a geometrical problem ill 64 Malfatti's problem ii 113 Hitchcock, Romyn, communication on re- cent improvements in microscopic ob- jectives, with demonstration of the resolving power of a new l-16th inch. Title only ix 16 Hoffman, Dr. A. W., cited on ultimate causes v 166 Page. Hoffman, W. J., cited ©n the poisoning of arrows ii 182 communication on the use of poisoned arrows by North American Indians. Title only ii 183 Holden, E. S., communication on the adopted value of the sun's apparent diameter. In full i95, (3) Sir William Herschel's observations of the satellites of Uranus. In full. ..i 106, (30) the number of words used in speaking and writing. In full ii 28, (16) two drawings of nebulae, made with the xxvi-inch telescope of the U. S. Naval Observatory, by Mr. L. Trouvelot, of Cambridge, Mass. Abstract il 51 search for Vulcan. Abstract ii 85 reference catalogues of astronomical papers and memoirs. Abstract ii 95 the shadow of the ball of Saturn pro- jected on the rings. Abstract ii 101 the brightness and the stellar magni- tude of (he third Saturnian satellite, Tethys. Read by A. N. Skinner. Title only iii 18 B. A. Gould's Uranometria Argentina. Reference iii 119, 122 Holmes, VV. H., remarks on glaciers vii 8 Homologies of the shoulder girdle of fishes..i 64 Homophenes vi 58, 76 Hooker, Thermometric observations by...v 94 Hooker, R., cited on natural law v 173 Hoosac tunnel. Acoustic features of ii 172 Hopkins, cited on the liquidity of the earth's interior il 76, 78 temperature of space 11 73 Hough, F. B., communication on the culti- vation of Eucalyptus on the Roman Campagna. Reference vi 36 Death of viii 25 House of Representatives, Ventilation of, v 99- Howland, Dr. E. P., remarks on Charleston earthquake ix 42- Hubbard, G. G., remarks on visible speech, vi 82 Hughes' microphone iv 184 Humboldt, Baron von, cited on transmission of sound v 41 Humidity observations vi 36 Humphreys, A. A., Eulogy on vii 4 Death of vii 3, 4 Humphreys and Abbot, cited on the delta of the Mississippi 1 (10), (12), (13) Huron, Altitude of Lake il 23 Huxley, T. H., cited on vital principle v 78. INDEX -TO VOLUMES I-X. 149 Page. Hydrometer employed to determine Specific gravity vl 26 Hygrometers vlii 25 Hygrometric observations vl 36 Hynoprs, J., cited on Malfatti's problem ii 118 Hyperion, Orbit of iii 26, 40, x 90, 104 Hypothesis, Use of. 11 164, vi xxxiii Hypsometry, Barometric v 48 New method of M 11 131 lee fields, Anticlinal and synclinal axes in 11 (22) pyramids vii 6 Iddings, J. P., communication on the col- umnar structure in the diabase of Orange Mountain, N. J. Abstract. 4 figures vili 19 Illinois, Flora of lv 99 Illiteracy and rainfall 1 68 Illumination of objects for examination with certain immersion objectives ii 126 Images of stars lx 15 Impressions on polished glass ii 39 Indexing scientific literature x 38 Indiau explanation of gravitation vl xxxi Indians as observers of nature vii 73 Errors respecting ii 175 (See also Anthropology.) Inductive reasoning vii lii Inertia vii 48 Infinite and infinitesimal quantities vi 133 attraction ii 19, vili 5S Ingestion among fishes lii 110 Initial meridian, Proposed vi 106 Inoculation of diphtheria iv 38 through mosquitoes vl 5 Insecticides vii 10 Insectivorous mammals v 118 Institutions, Evolution of vi xlviii Integrals, Elliptic... vii 102, ix 54 Integration of differential equations admit- ting periodic integrals x 100 Interior angle of objective iii 19 Intermarriage of the deaf. vl 83 International coinage iii 38 convention of teachers of the deaf and dumb iv 55 Geodetic Association on standard time..vi 106 scientific telegrams i 101 symbols for archseologie charts ii 72 Intervals, Musical ii 199 Investigation, Methods of. ii 163 Iowa, Loess and drainage system of vi 93 Quaternary of iv 120 Irby, J. R. M., communication on the crys- > talline state of matter. Abstract iii 39 Page. Irving, R. D., communication on the en- largement of mineral fragments as a factor in rock alteration. Title only..lx 16 Isogram x 4 Isoseismal map ix 37, 39 Ivory, James, cited on action at no dis- tance v 161 Jacobi's method for removing side-coeffi- cients vili 41 notation vii 103 Jackson, President, cited on the distribution of surplus among the States vi 103 Jackson, Dr., letter on autopsy of Agassiz. Communicated by J. J. Woodward. No abstract 1 93 Japan, Education in 11 69 Japanese coinage ill 38 dry painting vili 16 Jenkins, T. A., remarks on drifting buoy, vll 15 Johnson, A. B., communication on the his- tory of the light house establishment of the United States. Abstract and reference lv 135 recent investigations by the Light House Board on the anomalies of sound from fog-signals. In full. 2maps. 1 figurcv 23 some peculiar ravages of the Teredo navalis. Title only v 98 some eccentricities of ocean currents. Abstract ...vii 14 the difficulty in determining the direc- tion of sound. Abstract viil 11, 12 Johnson, W. P., communication on a new plane table. No abstract x 9 What is topography? Abstract x 15 Johnston, Gen., cited on the phenomena of sound ii (48) Jones, B., cited on phosphorus and brain disease v 75 Jones, Rev. George, cited on zodiacal light, i (19), (20), (21), (26) Journals of mathematics vl 117 Judd, F. F., communication on the water- shed of the Adirondack region. Ab- stract it 67 the Adirondack watershed. AbstracL.ll 82 Jukes, cited on ripple marks H 61, 62 Juvet, .communication on a time globe. Abstract lii 106 Kampf, Ferdinand, Death of ii 139 Kanab baseline iii 34 Keith, Reuel, communication on achro- matic object glasses. Title only i 73 150 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Keith, Reuel, communication on—Cont'd, the nature of the force of gravitation. Title only 1 89 Kempe, A. B., Trisection linkage of. x 99 Kerosene oil test9 11 72 Kerr, M. B., remarks on glaciers "vii 8 Kerr, W. C, communication on the geology ' of Hatteras and the neighboring coast. Abstract vi 28 the mica mines of North Carolina. Ab- stract vii 9 Death of. vill 25 Kidder, J. H., communication on deep sea temperature observations. Title only, ix 14 the gilding of thermometer bulbs. Title only lx 33 Kilauea ..vl 13 Kinematic theories of force v 126, vl xxviii King, A. F. A., communication on the con- servative element in disease. Ab- stract 11 111 the conservative influence of disease as illustrated in the phenomena of pul- monary phthisis. Abstract 11 124 the prevention of malarial diseases, illus- trating, inter alia, the conservative function of ague. Abstract vl 5 King, C, cited on geology of Great Basin... 1 56 King, Major, communication on the con- struction of the bridge across East River between Brooklyn and New York. Title only 1 23 the fatigue of metals. Title only 1 53 King, S. A., communication on the aerial currents observed in fifty balloon as- censions. Read by C. Abbe. Infull....i 35 Klaproth, cited on mineralogy t 78 Knight's tour vil 88 Knox, J. J., communication on the distribu- tion of loans in the Bank of France, the national banks of the United States, and the Imperial Bank of Ger- many. Abstract lv 31 the distribution of the surplus money of the United States among the States..vl 103 Kolb, Baron, cited on population iv 28 Koyl, C. H., communication on the storage of electric energy. Abstract v 46 Krakatoa and sun glows vil 35 Kummell, C. H., communication on compo- sition of error from single causes of error. Reference v 106 alignment curves on any surface, with special application to the ellipsoid. Abstract. J figure vl 123 Page. Kummell, C. H., communication on—Cont'd, the theory of errors* practically tested by target-shooting. Abstract. 2 figures, vl 138 curves similar to their evolutes. Ab- stract „ vil 87 the quadrie transformation of elliptic integrals, combined with the algo- rithm of the arithmetico-geometrjc mean. Abstract vil 101, 102 an artifice sometimes useful for the ad- justment of conditioned observations. Abstract viil 41 distances on any spheroid. Abstract and reference viil 52 Can the attraction of a finite mass be in- finite? Infull viii 58 the use of Somoff's theorem for evalua- tion of the elliptic integral of the third species. Reference ix 54 the brachisthode on the helicoid. Ref- erence x 90 remarks on temperature readings vl 26 infinitesimals vl 135 conic sections vi 149 music and the elements vii 28 Feuerbach's circle viii 52 time determinations viii 58 problem in probabilities x 89 trisection of angles x 100 Lagrange ignored by the Am. Phil. Soc, viii xxxviii Lagrange's method vii 93 Lake Bonneville 1 84, li 103 and the geoid vii 92, 101, ix 15 Lake Champlain, Ice phenomena on li (22) Lake Erie, Altitude of. 11 23 Lake, Great Salt H 187, 188 Lake Lahontan vii 18 Lake Michigan, Altitude of. ii 23 Lake Ontario, Changes of level in the basin of. ix 8 Lakelets and landslips ii 69 Lancaster's classification of meteorological literature x 26 Landen's transformation vil 107 Lands of the arid region 11 189 Landslips and lakelets il 69 Lane, J. H., cited on solar physics 1 31 Eulogy of. ill 122 Resolution on the death of Ill 123 Language, Evolution of. vi xlix written and spoken Hi 139 Laplace cited on the solar atmosphere and zodiacal light i (19), (27) INDEX TO VOLUMES I-X. 151 Page. Laplace ignored by the Am. Phil. Soc, rill xxxviii Laramie flora.- Till 17 Lassell cited on the satellites of Uranus, 1 (30), (34) Observations of Hyperion by. Ill 40 Latent heat v 137 impressions on glass 11 39 Latimer, George, Legacy by 11 48 Latitude, A method of determining 11 105 computations x 91 of Lockwood's farthest north- ix 9 variations of. Till 10 Lava fields of New Mexico vil 76 Leadville ores vi 32 Least square computation vi 150, viii 41 squares 162, 89 Le Conte, John, communication on the mi- croscopical structure of wool 11 62 Lee, W., communication on medallic medi- cal history. Abstract -vi 39 Lefavour, E. B., remarks on infinitesimals, vi 135 music and the elements vii 28 Lefroy, letter on changes of sea-level at Ber- muda. Communicated by J. Henry. No abstract 1 75 Legendre ignored by the Am. Phil. Soc, viii xxxviii Lehmus, Prof. D. C. L., cited on Malfatti's problem *. 11 115 Leibnita cited on Newton's philosophy v 162 Leibnitz's philosophy vil xlii Lenses, Achromatic combination of Ill 65 Cylindrical— vl 4 Le Sage's theory of cohesion v 129 Lesquereux, Prof. L., cited on fossil plants from Virginia. il (38), (40) Levees of the Mississippi delta i (14) Levelling instrument, Proposed ii 184 Lewes, G. H., cited on action at a distanee..v 157 PEpee's instruction of the dumb vl 63 Ley cited on cyclonic motion 1 107 l'Hospital's trisection instrument x 99 Liagre's theory of target shooting vi 138 Library of the Surgeon General's Office. _...l 92 Lick, James, letter on proposed observatory. Communicated by J. Henry. No ab- stract 1 91 Life 1 27, v 49, 102 and electricity v 57 force v 57 Modern philosophical conceptions of......v 49 Light and sound iv 143 of the sun, passed through a narrow slit, 111 119 Page. Light-house establishment of the United States Iv 135 Lightning, Cause of. il 189 Limnsea megasoma, Depauperation of ill 75 Limpets vil 4 Linnseus, cited on growth of stones v G7 mineralogy 1 77 Lippman, G., cited on electricity v 168 List of deceased members ill xiv, viii xxv, ix xxvi, x xxviii members 1 19, (37), ii ix, ill ix, 153, lv 15, vl5, vi xvi, vil xvi, viii xvi, lx xvi, x xvi members of the Mathematical Section. vi 116, vil 86, viii 36, lx 52, x 82 recipients of the Bulletin ill 159 The consolidated x 36 Lister, Prof. J„ cited on germ culture il 109 Lithology. See Geology. Littrow's telegraphic system i 101 Loans by banks in France, Germany, and the United States lv 31 Lockwood's expedition to farthest north.Jx 8 Locusts, Shower of. ii 87 Lodge, Dr. O. J., cited on electricity v 168 Loess of eastern Iowa vi 93 Origin of the lv 121 Logical algebra 1 88 Lombard, J. S., cited on brain temperatures, • v 75 Longitude computation viii 52 Loomis, Elias, cited on cyclonic motion, 1 107, 108 retardation of storm centres v 108 Lovering, Prof., cited on auroras 1 44 Loxodrome vi 124 Lucas, F. A., communication on museum specimens illustrating biology. Title only lx 36 Lucretius' philosophy vii xxxvii Lull, E. P., communication on the inter- oceanic canal through Nicaragua. Title only ii 83 Death of. x 8 Lunar theory iv 57, vi 136 variation of magnetic declination ill 47 Lymph, Motion of the 11 133 McClellan, Gen., cited on phenomena of sound 11 (48) McCullough, Hon. H., remarks on U. S. sur- plus given to the State of Indiana. ..vl 106 McDowell, S., cited on thermal belts vi 11 McGee, W J, communication on the drain- age system and the distribution of the loess of eastern Iowa. Abstract vi 93 152 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. McGee, W J, communication on—Cont'd. What is a glacier 1 Abstract vil 38 the terraces of the Potomac valley. Title only viii 24 the Charleston earthquake. Abstract..!*. 37 the quaternary deposits and the great displacement of the middle Atlantic slope. Reference x 1C remarks on earthquakes ix 42 Machin, cited on computation of ir i 58 McKenney and Hall, cited on diminution of Indians ii 175 McMurtrie, William, communication on the meteorological conditions affectiug the culture of the sugar beet. Reference, 111 142 Magic squares HI 143 Magnetic declination, Secular change in..lll 45 disturbance and northers vil 25 storms Ill 47 Magnetism. See Electricity. Main, R., cited on Saturn's rings vi 42 Mairan, cited on auroras 1 44 Malarial diseases, Prevention of vl 5 Malfatti's problem 11 113 Mallery, Garrick, communication on a cal- endar of the Dakota Indians. Abstract and reference 11 90 some common errors respecting the North American Indians. Abstract and reference 11 175 customs of every-day life. Abstract. ..ix 19 relations between Professor Baird and participating societies x 45 romarks on phonetic alphabets Ix 18 Mallet's contraction hypothesis vl 90 method of determining earthquake foci, x 17, 19 Maloney, J. A., Electric investigations by..v 47 Mammals, Classification of 11 (3) Distribution of. 11 26 Insectivorous v 118 Manganese, Estimation of. 11 132 Man, Zoological relations of 1 24 Mann, B. P., communication on reference indexing. Abstract x 38 remarks on care of pamphlets vill 29 throvving-sticks Ix 14 Map of Charleston earthquake Ix 37, 39 Gulf of Mexico iv 52 path of meteor of December 24, 1873.. ..11 160 Topographic x 11 Maps for use in connection with the transit of Venus, 1874 1 G3 Marcou, J., cited on paleozoic rocks vl 102 Mariotte, Law of... v 139 Page. Mars, Satellites of. 11 181, 186, 188. 190, vl 45 Marsh, Hon. G. P., citad on individual vo- cabularies 11 (16), (19), (21) Marth's method vil 98 Martin, Artemas, communication on a prob- lem in probabilities. Abstract x 80 methods of finding nth-power numbers whose sum is an nth-power. Abstract..*. 107 Letter from vil 87 Marvin, C. F., communication on the Flood Rock explosion. Title only vill 28 the electrometer as used in observations of atmospheric electricity. Titleonly.jx, 9 Marvine, A. R., Biographical notice of 11 (53) Resolutions on the death of 11 84 Mass of a planet determined from observa- tions on two satellites vl 132 Mason, O. T., communication on archaeolog- ical specimens. Title only 11 48 the classification of objects of archae- ology. Title only 11 50 international symbols for charts of pie- historical archaeology. Title only ...11 71, 72 the decipherment of some Aztec monu- ments lately discovered in Guatemala. Title only Ill 37 comparison of written language with that which is spoken only. Abstract, 111 139 two examples of similar inventions in areas widely apart. Abstract Ix 12 bowyers and fletchers. Abstract Ix 44 remarks on implements of Australia, Aleu- tian Islands, and North America 11 66 the telephone 11 104 ancient Indian population 11 180 charcoal in the drift Iv 122 Indian observation of nature vil 74 origin of customs Ix 21 Mason, , communication on kerosene oil tests. Abstract ii 72 Mathematical journals vi 117 Mathematical Section, Minutes of...vi 121, vil 87, viii 37, ix 53, x 83 Organization of vi 28, 121 place of meeting vil 81 Statistics of x 34, 36 Mathematics, List of papers on (See also Astronomy) : on the distance traversed by approaching the North Pole on a loxodromic curve. J. E. Hilgard. Title only 1 21 [exhibition of chronograph.] J. E. Hil- gard. No abstract 1 22 on a curve of the fourth degree. A. Hall. Abstract and reference i 30 INDEX TO VOLUMES I-X. 153 Page. Mathematics, List of papers on—Cont'd. on an exponential formula having refer- ence to the tolerance allowed at the U. S. Mint. J. E. Hilgard. Title only, 1 31 on the locus of the point of equal illumi- nation by two unequal lights treated by the quaternion analysis. E. B. Elliott. Title only i 35 on Hindoo arithmetic. J. E. Hilgard. Title only 1 53 on a series for the determination of the number expressing the ratio of the circumference to the diameter. E. Frisby. In fall i 57 on the experimental determination of the ratio of the circumference to the di- ameter, based on the principles of the calculus of probabilities. A. Hall. Title only i 62 an historical note on the method of least squares. A. Hall. Reference i C2 an inquiry into the law of probability. J. E. Hilgard. Titleonly i 84 on logical algebra. C. S. Peirce. Refer- ence i 83 on the mechanical representation of a problem in least squares. S. New- comb. Reference 1 89 on quaternions, as developed from the gen- eral theory of the logic of relatives. C. S. Peirce. Title only i 94 on affected quantities of the first order. E. B. Elliott. Title only 11 42 approximate quadratures. A. Hall. Ab- stract 11 48 some recent investigations on the theory of invariants. J. J. Sylvester. Title only 11 95 a trigonometrical formula. B. Alvord. Title only 11 104 the history of Malfatti's problem. M. Baker. In full. Zfigures 11 113 series. E. Frisby. Title only 11 193 the intersection of circles and the inter- section of spheres. B. Alvord. Title only 11 198 an adjustment of the Carlisle tables of re- versions and annuities. E. B. Elliott. Title only 11 201 new points respecting the intersections of circles and the intersections of spheres. B. Alvord. Title only 11 201 discussion of a geometrical problem, with bibliographical notes. M. Baker. In full. 4 figures 11153, 55 Page. Mathematics, List of papers on—Cont'd. on magic squares. E. Frisby. Abstract. 6 figures Ill 143 on the geometrical problem to determine a circle equally distant from four points. M. H. Doolittle. Abstract.. ..v 88 on some of the properties of Steiner's power-circle. B. Alvord. Title only.rv 8tf on composition of error from single causes of error. C. H. Kummell. Reference, v 106 on a geometrical question relating to spheres. M. Baker. In full v 107 on a graphic table for computation. G. K. Gilbert. Abstract v 120 experiments in binary arithmetic. H. Farquhar. Abstract v 125, vl 3 formulas for the computation of Easter. E. B. Elliott. In full vl 14 further experiments in binary arithmetic. H. Farquhar. Abstract vl 38 inaugural address of the chairman of the Mathematical Section. A. Hall. In full vl 117 a quasi general differentiation. A. S. Christie. Titleonly vl 122 infinite and infinitesimal quantities. M. H. Doolittle. Abstract vl 133 certain possible abbreviations in the com- putation of the long-period perturba- tions of the moon's motion due to the direct action of the planets. G. W. Hill. Abstract and reference vl 136 the theory of errors practically tested by target-shooting. C. H. Kummell. Ab- stract. 2figurcs vl 138 a special case in maxima and minima. B. Alvord. Abstract vl 149 form of least-square computation. H. Far- quhar. In full vl 150 note on the problem discussed by Mr. Al- vord. H. Farquhar. Abstract vl 152 the rejection of doubtful observations. M. H. Doolittle. Abstract vl 152 the special treatment of certain forms of observation-equations. R. S. Wood- ward. Abstract vl 156 contact of plane curves. A. S. Christie. Abstract vl 157 curves similar to their evolutes. C. H. Kummell. Abstract vll 87 the problem of the knight's tour. G. K. Gilbert. Abstract vll 83 empirical formulae for the diminution of amplitude of a freely-oscillating pen- dulum. H. Farquhar. Abstract vll 89 154 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Mathematics, List of papers on—Cont'd. the formulae for computing the position of a satellite. A.Hall. In full vii 93 a form of the multinomial theorem. A. S. Christie. Title only vii 101 the quadric transformation of elliptic inte- grals, combined with the algorithm of the arithmetico-geometric mean. C. H. Kummell. Abstract vii 101, 102 a case of discontinuity in elliptic orbits. \V. B. Taylor. Abstract vii 122 the verification of predictions. M. H. Doolittle. Abstract vii 122 methods of verifying weather predictions. C. Abbe. Abstract viii 8 example illustrating the use of a certain symbol in the calculus of affected quantity. E.B.Elliott. Title only..-vill 37 a collection of formulae for the area of a plane triangle. M. Baker. Reference, viii 37 an artifice sometimes useful for the adjust- ment of conditioned observations. C. H. Kummell. Abstract viii 41 a group of circles related to Feuerbaeh's circle. M. Baker. In full. 4 figures, viii 45 distances on any spheroid. C. H. Kum- mell. Abstract and reference viii 52 on Grassmann's system of geometry. A. Ziwet. Reference viii 53 cause and chance in the concurrence of phenomena. M. H. Doolittle. Title only viii 54 Can the attraction of a finite mass be infi- nite? C. H. Kummell. In full viii 58 on the use of Somoff's theorem for the evaluation of the elliptic integral of the third species. C. H. Kummell. Reference ix 54 graphic methods in research. G. K. Gil- bert. Abstract x 4 association ratios. M. H. Doolittle. Ab- stract x 83 a problem in probabilities. Symposium. Abstract x 87, 89 on the free cooling of a homogeneous sphere initially heated to a uniform temperature. R. S. Woodward. Ref- erence x 90 on the brachisthode on the helicoid. C. H. Kummell. Reference x 90 the motion of Hyperion. G. W. Hill. Ab- stract and reference x 90 the parallax of a Tauri. A. Hall. Ab struct * 91 Page. Mathematics, List of papers on—Cont'd, the most probable value of the latitude and its theoretical weight from entangled observations occurring in the use of Talcott's method. A. S. Flint. Ab- stract x 91 association ratios. M. H. Doolittle. Ab- stract x 93, 94 [solution and generalization of a problem requiring the division of a rectangle into parts which form a square.] H. Farquhar. No abstract x 96 a collection of solutions of the trisection problem. M. Baker. Abstract x 96 [on the trisection problem.] G. E. Curtis. Abstract x 98 the integration of differential equations admitting periodic integrals. G. W. Hill. Abstract and reference x 100 Euler's theorem (generally called Lam- bert's). A. Hall. Abstract x 101 [a new computing machine.] E. B. Elliott. Abstract x 102 on the constant P in observations of ter- restrial magnetism. W. Harkness. Abstract and reference x 102 the conditioned cooling of a homoge- neous sphere. R. S. Woodward. Ref- erence x 103 the orbit of Hyperion. O.Stone. Abstract and reference x 104 the quotients of space-directed lines. E. B. Elliott. Abstract x 105, 106 methods of finding n^-power numbers whose sum is an nth-power. A. Martin. Abstract x 107 Matter and force vii 30 Combination of. vi xxxv Properties of. i 27,v 127, vi 5, vii 40 Three states of. v 136 Matteueci cited on muscular contraciion...v 59 Matthews, Washington, communication on natural naturalists. Read by J. S. Bill- ings. Abstract vii 73 mythological dry paintings of the Nava- jos. Abstract viii 14 anthropometric and reaction-time appa- ratus. Abstracts _..viii 25 Mauna Loa vi 13 Maxima and minima, Special case in..vi 149, 152 Maxwell, Prof. J. C, cited on matter v 128 on elasticity v 132 theories of heat v 13*4 radiant energy v 136 Boyle's law v 139 molecular orbits v 140, 147, 149 INDEX TO VOLUMES I-X. 155 Page. Maxwell, Prof. J. C, cited on—Cont'd. dissipation of molecular energy v 153 surface repulsion v 155 vortex rings vii liv matter vii 44 Mayer, A. M., communication on a method of determining a definite interval of time, and its application to measuring the number of vibrations of solid bod- ies. Title only ii 64 Mayer's topophone viii 13 Mechanical representation of a problem in least squares i 89 Medallic medical history vi 39 Medals, Exhibition of. v 22 Meehan, Thos., cited on the common names of plants iv 113 Meek, F. B., communication on new species of fossil plants from Alleghany Co., Virginia; with some remarks on the rock seen along the Chesapeake and Ohio railroad, near the White Sulphur Springs of Greenbrier county, West Virginia. Read by T. Gill. In full. 2 plates-..: i 62, ii (26) Death of. „ ii 111 Meigs, M. C, communication on a map of the head waters of the Yellowstone and Lewis rivers. No abstract i 21 the movements caused in large ice-fields by expansion and contraction, as illus- trative of the formation of anticlinal and synclinal axes in geological for- mations. In full. 4 figures ii 33, (22) remarks on glacial period ii 37 Members. See List of Members. Membership statistics of scientific socie- ties x 29 Memoir on the scientific work of Joseph Henry ii 203 Memorial to B. Alvord vii 127 (See also Biography.) Mendenhall, T. C, communication on the measurement of temperature at dis- tant points. Title only viii 18 the Charleston earthquake. Abstract, ix 37 remarks on Japanese customs ix 21 Mercadier, M., cited on radiophony iv 158 Mercury, Theory of. viii 41 Transit of. ii 199, iii 43 Meridian, Proposed initial vi 106 Meridian transit time determinations...viii 55 Merriam, C. H., communication on the eco- nomic phase of the English sparrow question. Reference x 16 Page. Merrill, G. P., communication on geological museums. Title only ix 36 Metaphysic philosophy vi xxx Metaphysics vii xxix Metcalf, Capt. H., cited on theory of target practice vi 145 Meteor, Explanation of explosion of ii 143 of December 24, 1873 i 94, ii 123, 139 (See also Meteors.) Meteoric matter and planetary motions, ii 1S8, 190 Meteorite, A new vii 32 Meteorites at Concepcion and San Gregorio, New Mexico i 24 Meteorological work by Joseph Henry ii 236 of the Smithsonian Institution ii 295 Meteorology, List of papers on (See also Thermometry) : on the aerial currents observed in fifty balloon ascensions. S. A. King. Com- municated by C. Abbe. In full i 35 [on aerial currents observed in balloon ascensions.] C. Abbe. Abstract i 38 on certain remarkable effects of lightning. E. J. Farquhar. Communicated by J. Henry. Title only i 42 on the aurora. W. B. Taylor. Abstract. ,.i 43 on the aurora of February 4th [1872]. J. E. Hilgard. Abstract 1 47 on the effects of winds and barometric pressure on the tides of Boston, and on the mean level of the sea. W. Fer- rel. Abstract and reference 1 53 on the meteorology of Japan. T. Autisell. Title only i 70 on the results of astronomical observa- tions at Sherman Station, Wyoming Terr. R. D. Cutts. Abstract and refer- ence i 70 on the laws of condensation of aqueous vapor in the atmosphere. E. Foote. Title only i 74 on the meteorology of Russia. A. Woeikof. Reference i 75 on atmospheric electricity. (3 papers.) J. Henry. Title only 175,87 on electrical phenomena in the Kocky Mountains. F. M. Endlich. Title only, i 95 on the distribution of temperature over the surface of the globe. W. Hark- ness. Reference 1 96 on some causes that produce rain. E. Foote. Title only 1 98 on the laws governing the movement of storm centres. C. Abbe. Abstract... 1 99 156 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Meteorology, List of papers on—Cont'd, on the law connecting the velocity and di- rection of the wind with the barometric gradient. W. Ferrel. Abstract i 106 on the correlation of the winds and the temperatures of the surface waters of the ocean along the coast of New Hampshire. J. W. Chickering. Ab- stract ii 17 meteorological observations in Peru, and some of the meteorological conditions of that country. A. Woeikof. Title only ii 38 the glacial theory. J. Henry. Abstract.Xi 35 the causes of glacial climate. Symposium. Abstract ii 43, 45 the comparison of rain-gauges at different elevations. J. R. Eastman. Abstract.Xi 49 a new meteorological instrument. J. W. Osborne. Abstract ii 63 the hygrometrical condition of the air in high latitudes. E. Bessels. Title only, 11 66 the horary oscillations of the temperature of the atmosphere. G. K. Gilbert. Ab- stract ii 67 horary oscillations of the atmosphere. G. K. Gilbert. Abstract ii 69 facts relating to the falling of waterspouts in North Carolina. T. L. Clingman. Abstract ii 104 the causes of electrical developments in thunderstorms. E. Foote. Abstract..Ii 189 suggestions respecting the study of mete- orology in regard to the causes of yel- low fever. J. W. Osborne. Title only, lii 21, 27 a curious manifestation of force by the wind. J. VV. Osborne. Title only....ill 27 air currents on mountain slopes. G. K. Gilbert. Abstract ill 38 on the meteorological conditions affect- ing the culture of the sugar beet. W. McMurtrie. Reference iii 142 [the aurora boreatis.] C. Abbe. Abstract.Xv 21 on the' conditions determining tempera- ture. W. Ferrel. In full v 90, 91 on errors of barometric observations pro- duced by wind. G. K. Gilbert. Refer- ence v 91 on solar radiation at Sherman, Wyoming. W. Ferrel. Title only v 101 on the retardation of storm centres at ele- vated stations, and high wind as a probable cause. H. A. Hazen. In full v 108 Page. Meteorology, List of gapers on—Cont'd, [a remarkable halo.] W. B. Taylor. Ab- stract v 112 on a graphic table for computation. G. K. Gilbert. Abstract v 120 on the coming winter of 1882-'83. H. A. Hazen. Abstract v 122 the response of terrestrial climate to secu- lar variations in solar radiation. G. K. Gilbert. Abstract vi 10 the thermal belts of North Carolina. J. W. Chickering. Abstract vi 11 hygrometric observations. H. A. Hazen. Abstract vl 36 the Rochester (Minnesota) tornado. J. R. Eastman. Abstract vii 3 the sun-glows. H. A. Hazen. Abstract and reference vll 17 the relations between northers and mag- netic! disturbances at Havana. G. E. Curtis. Reference vll 25 methods of verifying weather predictions. C. Abbe. Abstract viil 8 thunderstorms of 1884. H. A. Hazen. Ab- stract vlli 10 the condensing hygrometer and sling psy- chrometer. H. A. Hazen. Abstract, viii 25 normal barometers. T. Russell. Title only lx 46 the sky-glows of 1883. H. A. Hazen. Title only x 6 the theory of the wind-vane. G. E. Curtis. Reference x 9 the electrometer as used in observations of atmospheric electricity. C. F. Mar- vin. Title only x 9 relation between wind velocity and press- ure. H. A. Hazen. Reference x 10 the Signal Service bibliography of meteor- ology. C. Abbe. In full x 20 memorandum on the Signal Service bibli- ography of meteorology and terrestrial magnetism. C. J. Sawyer. Read by C. Abbe. In full x 23 Meteors and comets 1 94 Method of least squares..i 62, 89, vl 150, vlli 41 research 11 163, vl xxxiii, vll li Methods of evolution vi xxvii modern petrography vll 36 verifying predictions vll 122 verifying weather predictions viil 8 Metric system vl 4 advocated by Geodetic Commission. ...vl 109 for postal purposes ii 15, 19 in microscopy ill 22 INDEX TO VOLUMES I-X. 157 Mexico, Gulf of. iv 52 Meyer's atomic volume curve vil 15 Mica mines of North Carolina vii 9 Michelson.A. A.,communication on the mod- ifications suffered by light in passing through a very narrow slit. Abstract.iii 119 Michigan, Altitude of Lake li 23 Micrometry, Standard for ill 22 Micron itt 23 Microphone, Hughes' iv 184 Modification of Wheatstone's iv 183 Microscopy, List of papers on (See also Optics) : on the desirability of reproducing photo- graphs of scientific objects and espe- cially of magnified microscopical prep- arations in a permanent form by some photo-mechanical method. J. J.Wood- ward. Abstract i 41 on the use of monochromatic sunlight as an aid to high power definition. J. J. Woodward. Abstract and reference i 47 on micrometric writing on glass. J. J. Woodward. Title only i 93 on the modern microscope, Nobert's lines, and the attempts of others to construct them. J. J. Woodward. Title only.. .ii 25 diffraction phenomena in the field of the microscope. J. J. Woodward. Abstract and reference ii 60 the microscopical structure of wool. J. J. Woodward and John Leconte. Title only ii 62 the use of photography in connection with the micrometer measurement of blood corpuscles. J. J. Woodward. Title only ii 79 a simple device for the illumination of balsam-mounted objects for examina- tion with certain immersion objectives whose "balsam angle" is 90° or up- wards. J. J. Woodward. In full. 1 figure ii 126 on the apertometer of Prof. E. Abbe, of Jena, Germany. J. J. Woodward. Ab- stract iii 18 on a standard for micrometry. J. J. Wood- ward. Abstract iii 22 on the oil-immersion objectives of Zeiss, and on convenient methods of obtain- ing oblique illumination for these and similar objectives. J. J. Woodward. Abstract iii 25 a new apertometer for microscopic ob- jectives. J. J. Woodward. Title only Hi 37 microscopy, List of papers on—Cont'd. Riddell's binocular microscopes—an his- torical notice. J. J. Woodward. Ab- stract and reference iv 35 [exhibition of a collection of microscopes.] J. S. Billings. No abstract vii 73 recent improvements in microscopic ob- jectives, with demonstration of the resolving power of a new l-16th inch. R.Hitchcock. Title only ix 16 Milneria minima viii 5 Mills, cited on thermometry ix 30 Mind and body v 72 Mineralogy, List of papers on : on mineralogical systems. F. M. Endlich. In full i 77 on specimens of meteoric iron from Chi- huahua, Mexico, and the structure of meteorites in general. F. M. Endlich. Title only I 98 on the occurrence of pure tellurium in certain gold mines of Colorado. F. M. Endlich. Title only i 101 on some interesting cases of metamorph- ism. F. M. Endlich. Title only iii 27 some observations on the crystalline state of matter. J. R. M. Irby. Abstract...iii 39 topaz from Stoneham, Maine. F.W. Clarke and J. S. Diller. Abstract and refer- ence viii 5 the enlargement of mineral fragments as a factor in rock alteration. R. D. Irving. Title only ix 16 the present status of mineralogy. F. W. Clarke. Title only x 6 Misapplication of geographical terms i 39 Miscellaneous Papers, List of: anniversary address, Nov. 18, 1871 ; [on the organization and objects of the Soci- ety.] J.Henry. In full i v, 34 on the preservation of foods. A. B. Eaton. Title only i 22 [exhibition of a chronoscope.] J. E. Hil- gard. No abstract i 23 on the construction of the bridge across East River between Brooklyn and New York. Major King. Title only i 23 on the new coinage of Japan. E. B. Elliott. Title only i 31 on apothecaries' weights and measures. B. F. Craig. Title only i 34 on the measurement of the pressure de- veloped by the explosion of gun- powder in firearms. C. E. Dutton. Title only * 62 158 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. miscellaneous Papers, List of—Cont'd. on the expenditure of the income of the Bache fund for 1872. J. Henry. Title only 1 63 an account of some recent experiments on different kinds of gunpowder at Fort- ress Monroe. C. E. Dutton. Title only 1 54 [the Woodbury photo-relief process.] J. J. Woodward. Abstract i 57 [the condition of the Society.] J. Henry. No abstract 1 64 on the water supply of cities. B. F. Craig. Title only 1 65 on the collection of a large library. J. S. Billings. Abstract i 92 a description of a new spirometer. G. A. Otis. Title only i 94 on recent improvements in the economy of fuel. C. E. Dutton. Title only i 96 on recent improvements in the manufac- ture of steel. C. E. Dutton. Titleonly, 1 97 on Giffard's injector. J. Henry. Title only i 99 on the method adopted in writing the in- ternational scientific telegrams. A. Hall. Abstract I 101 [on scientific culture in the Argentine Re- public] B. A. Gould. No abstract...ll 15 on the present state of the sciences. C. W. Shields. Abstract and references...U 16 on the gathering, packing, transportation, and exposure of fruits for sale. S. C. Busey. Titleonly 11 16 on the failure of the wooden pavements of Washington City. L. D. Gale. Ab- stract 11 26 on latent impression* on polished glass plates produced by heating the plates in close connection with engraved me- tallic plates. A. C. Ross. Abstract...11 39 iron facing copper plates. J. E. Hilgard. Abstract 11 42 the progress of the natural sciences dur- ing the past century. T. N. Gill. Ref- erence 11 56 cylinder condensation, steam jackets, and superheated steam. G. B. Dixwell. Title only 11 64 the coinage of the Argentine Republic. B. A. Gould. Communicated by E. B. Elliott. Abstract 11 65 the progress which [has] been made in educational matters in [Japan.] D. Murray. Abstract 11 69 Page. miscellaneous Papers, List of—Cont'd. illuminating materials. J. Henry. Title only 11 71 [kerosene oil tests.] Mason. Ab- stract 11 72 paper made of asbestos. J. Henry. Title only 11 86 the burning of theatres and public halls. 'J. M. Toner. Reference 11 95 the rulings on glass by Mr. Rogers, of Cambridge. J. J.Woodward. Abstract, 11 130 the uses of [the] dynagraph, and the work performed in determining the resist- ance of trains, etc. P. H. Dudley. Ab- stract Ill 29 phosphorescent clocks. J. E. Hilgard. Abstract HI 33 the work of tho National Board of Health. J.S.Billings. Titleonly Ill 50 [yellow fever disinfection.] F. M. Gun- nell. Abstract Ill 51 [exhibition of a time globe.] Juvet. Abstract Ill 106 sugar from sorghum. P.Collier. Abstract, 111 140 the scientific work carried on under the direction of the National Board of Health. J. S. Billings. Abstract, lv 37 the history of the light house establish- ment of the United States. A. B. Johnson. Abstract and reference lv 135 relation of meteorological conditions to the summer diarrhoeal diseases. S. C. Busey. Abstract and reference lv 165 [exhibition of a panoramic photograph.] W. B. Taylor. Abstract v 21 [exhibition of coins and medals.] J. M. Toner. Abstract v 22 on the ventilation of the House of Repre- sentatives. J. S. Billings. Abstract, v 99 on the philosophical order of the sciences. C. W. Shields. Reference v 105 on the fisheries of the world. G. B. Goode. Reference v 117 the cultivation of eucalyptus on the Roman Campagna. F. B. Hough. Ref- erence vi 36 sketches from medallic medical history. W. Lee. Abstract vl 39 fisheries exhibitions. G. B. Goode. Ref- erence vll 26 American scientific societies. A. Hall. Presidential address. JnfulL.-vUi xxxiii, 30 INDEX TO VOLUMES I-X. 159 Page. Miscellaneous Papers, List of—Cont'd, the systematic care of pamphlets. G. Brown Goode. Abstract and reference, viii 29 the systematic care of pamphlets. C. V. Riley. Abstract viii 29 scientific men and their duties. J. S. Bill- ings. Presidential address. In full, ix xxxv, 46 when I first saw the cholera bacillus. R. D. Mussey. Title only ix 22 the frequency of coincidences. L. F. Ward. Abstract x 8 Manchester meeting of the British Asso- ciation for the Advancement of Sci- ence, 1887. F. W. Clarke. Title only...x 19 on reference indexing. B. P. Mann. Ab- stract x 38 Mississippi delta 1 (10) Missouri, Valley of the Upper vii 20 Mivart, St. G., cited on life v 52 Model of the basin of the Gulf of Mexicc.lv 52 Mohs, cited on mineralogy i 78, 79 Molecular excursions v 140, 141 heats of similar compounds i 104 kinetics v 133 physics. See Physics. Molecules, atoms, and waves i 66 size of v 141 complexity of v 147 Mollusks, Appendages of vii 32 found at great depths v 90 Observations on iii 75 Two remarkable viii 5 Moore, Commander, cited on Plover Bay..iv 124 Moon, Theory of iv 57, vi 136 Moon's eclipse of June 11, 1S81 v 90 motion, Computation of. vi 136 Money, Gold and silver iii 78, 107 Mono craters vii 19 Monochromatic aberration in aphakia vi 5 sunlight as an aid to high definition i 47 Monoclinal ridges ...ii 74 More, Henry, cited on matter vii xlii Morphology, Biologic —iv 123 of the antlers of the Cervidse ii 135 Morse, E. S., cited on disparity of sexes in Buccinum iii 75 Mortality among army officers „ ii 49 statistics of the tenth census iv 164 Mosher, Experiments of ». ii 40 Mosler, cited on phosphorus and cerebral activity _ v 75 Mosquito inoculation vi 5 Mosso, Plethysmograph of. v 77 Motion, Laws of vii 56 Page. Motion, Modes of._ vi xxxviii of a particle toward an attracting centre, i 88, 11 19, vii 122 Transmutation of vi xxviii Mount Dana glacier vii 5 Mount Lyell glacier vii 6 Mount Rainier and its glaciers x 10 Mount Taylor, Geology of vii 77 Mount Washington meteorological observa- tions v 108 Movement of storm centres 1 99 Muir's glacier observations vii 8 Munroe, C. E., communication on the esti- mation of manganese as pyrophos- phate. Read by T. Antisell. Referenccit 132 the determination of the specific gravity of solids by the common hydrometer. In full vi 26 Murdoch, John, remarks on throwing- sticks Ix 13 Murray, David, communication on the pro- gress which has been made in educa- tional matters in Japan. Abstract.. ..11 69 Muscular contraction v 58 Museum, National Ii 292 Museum specimens illustrating biology...ix 35 Music and the chemical elements vii 26 Musical intervals 11 199 Mussey, R. D., communication on the appli- cation of physical methods to intel- lectual science. Abstract vii 18 when I first saw the cholera bacillus. Title only Ix 22 remarks on artesian wells v 101 phonetic alphabets ix 18 Myer, A. J., Death of. Iv 23 Resolution on the death of. iv 31 Mythological dry painting of the Navajos, viii 14 Mythology of the Numas i 96 National Academy of Sciences viii xl National Board of Health, Scientific work by the iv 37 National Museum 11 292, x 57 Natural naturalists vii 73 Navajo dry painting viii 14 Naval Observatory, New telescope of. 1 62, 63 star catalogue 1 74 Navigation, Sumner's method in ii 105 Nebraska, Quaternary of iv 120 Nebula of Andromeda ix 14 Nebulsa, Drawings of ii 51 Planes of certain i 109 Nebular hypothesis and the satellites of Mars- ii 186, 188, 190, vi 45 160 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Necks of volcanoes vll 78 Nerve currents v 60 Neve and glacier denned vii 37 Nevada, Glacial epoch in i 84 Physical features of i 54 Volcanic activity in 1 99 New Hampshire, Relation of winds to sea temperature on the coast of. ii 17 New Mexican volcanoes and lava-fields. ..vii 76 New star .*..ix 14 Newberry, Dr. J. 8., cited on fossil plants from Virginia ii (38), (42) Newcomb, Simon, communication on the transits of Venus, past and future. Title only i 29 the possibility of a universal atmos- phere. Title only i 52 the progress of the construction of the new telescope for the Naval Observa- tory. Reference 1 62, 63 the proceedings of the commission to arrange for the observation of the next transit of Venus. Title only i 65 the mechanical representation of a problem in least squares. Reference..! 89 the transit of Venus. Title only ii 41 tt thermodynamic theory of the spec- trum. Title only iii 41, 43 the cosmogony. Titleonly ii 113 the recent transit of Mercury [1878]. Abstract- ii 199 observations of the total solar eclipse, July 29, 1878. Abstract ii 202 the recurrence of eclipses. Titleonly. .iii 33 a recent visit to California to inspect a site for the new Lick observatory. Title only iii 45 the future of the human race regarded from the standpoint of evolution. Presidential address, 1879. Title only.Ml 52 the principles of taxation. Title only, iii 119 the relation of scientific method to so- cial progress. Presidential address, 1880. In full iv 40 the speed of propagation of the Charles- ton earthquake. Reference x 28 remarks on auroras i 46 the radiometer ii 81 passage of light through a narrow slit, iii 120 auroras iv 22 Benjamin Peirce... iv 26 Newton, Henry, Researches in the Black Hills by iii 125 Newton, Prof. H. A., cited on the aurora...iv 22 Page. Newton, Sir Isaac, eked on action at a dis- tance V 159 atoms vii xliv elasticity v 130 laws of orbits v 146 the spectrum v 142 the ultimate v 165, 167 trisection of angles x 97 Newton's rings v 155 Newtonian formula of gravitation, Modifica- tion of. viil 39 philosophy vii 45 Niagara Falls, Earth tremors at iv 186 Nichol, J. P., Thermometric experiments of v 93 Nicholson, W. L., report of the committee to collect information relative to the meteor of December 24th, 1873. In full. Map and 2 figures ii 139 remarks on the effect of magnetism on the length of magnetic bars ii 373 Nomogram x 4 Normal section in geodesy vi 123 North American Indians, Errors respecting, ii 175 North Carolina coast, Geology of. vl 28 earthquakes i 101, 104 mica mines vii 9 thermal belts vi 11 waterspouts ii 104 Northers and magnetic disturbance vii 25 Nt&-power numbers whose sum is an n">. power x 107 Numas, Genesis and demonology of i 104 Mythology of. i 96 Nymphalidse, Pupation of. iii 41 Objective, Interior angle of iii 19 Achromatic iii 65 Objectives, Color corrections to achromatic, iii 39 Oil-immersion iii 25 Oblateness of the earth, Change in viil l!i Oblique illumination in microscopy iii 25 Observation and experimentation, Princi- ples of. ~ ii 163, vii Ii Observation equations, Special treatment of certain vi 156, viii 41 Observations of the meteor of Dec. 24, 1873..U 1 1 1 Occult force vi xxxiii qualities WO Oceanography, List of papers on : on the effects of winds and barometric pressure on the tidws of Boston, and on the mean level of the sea. W. Fer- rel. Abstract and reference i 53. INDEX TO VOLUMES I-X. 161 Oceanography, List of papers on—Cont'd. [letter on changes of sea-level at Ber- muda.] J. H. Lefroy. Communicated by J. Henry. No abstract i 75 on the tides of the Bay of Fundy. Mr. Ramsay. Communicated by J. J.Wood- ward. Title only t 94 Sumner's method in navigation. J. H. C. Coffin. Infull 14 105 the navy compass. B. F. Greene. Title only 11 123 an adjustable binnacle for the correction of a ship's compass. B. F. Greene. Title only 11 134 optical salinometer. J. E. Hilgard. Ab- stract 11 185 temperatures of the Pacific OEean. T. Antisell. Abstract 11 192 the deepseadredgingsin the Gulf of Mex- ico and the West Indies in 1873-1878, by Professors Louis and Alexander Agassiz and the officers of the U. S. Coast Survey. W. H. Dall. Title only, iii 45 on Siemens' deep sea thermometer and Carre's ice machine. J. E. Hilgard. Title only v 100 some eccentricities of ocean currents. A. B.Johnson. Abstract vii 14 historical sketch of deep sea temperature observations. J. H. Kidder. Title only Ix 14 Odor, Theory of. viii 27 Office, Rotation in v 49 Officers, Duties of. (See Standing Rules.) for 1871 1 20 1872 1 32, 33 1873 1 64 1874 1 91 1875 11 16 1870 11 x, 59, 84 1877....'. 11 86 1878 11 161 1879 ill 17 1880 11151,53,151 1881 lv 30 1882 v 14, 85, 112 1883 v 175, vl xiv, 41, 122 1884 vl xv, vii xiv, 36, 85 18S5 -vii xv, viii xiv, 30 1886 .-viii xv, ix xiv, 52 1887 ix xv, x xiv, 82 1888 x xv of the Army and Navy as scientific admin- istrators Ix xlix 57 Page. Ogden, H.G., communication on What is to- pography? Abstract x 15 Oil-immersion objectives Ill 25 Oldberg. R., The Flora Columbiana of lv 65 Omaha Indians, Gentile system of. Ill 128 Omar Cheyam, Calendar proposed by il 38 Onatsevich, Lt. M. S., Co ordinates of Plover Bay by lv 128 Ontario Basin, Changes of level in Ix 8 Ophthalmology. (See Optics.) Optical salinometer 11 185 Optics, List of papers on (see also Micros- copy) : on a new method for detecting and measuring the optical defects of the eye. W.Thomson. Reference i 22 on achromatic object glasses. R. Keith. Title only 1 73 [exhibition of spectra and spectroscopes.] J. J. Woodward. No abstract 1 89 half-vision. J. Henry. Title only 11 60 the markings on Navicula rhomboides. J. J.Woodward. Title only 11 69 the color corrections of achromatic object- ives. W. Harkness. Abstract Ill 39 a thermodynamic theory of the spectrum. S. Newcomb. Title only ill 41, 43 some apparatus recently brought into use by the medical department of the Army for the examination of the eye. J. J. Woodward._ Abstract Ill 53 the number of lenses required in an ach- romatic objective, consisting of infi- nitely thin lenses in contact, in order that, with any given law of dispersion whatever, the greatest possible num- ber of light-rays of different degrees of refrangibility may be brought to a common focus. W. Harkness. In full Ml 65 the modifications suffered by light in pass- ing through a very narrow slit. A. A. Michelson. Abstract Ill 119 color perception and color blindness. S. M. Burnett. Abstract and reference, lv 54 refraction in the principal meridians of a triaxial ellipsoid, regular astigmatism and cylindrical lenses. S. M. Burnett. Reference vi 4 the monochromatic aberration of the human eye in aphakia. W. Harkness. Reference vl 5 the character of the focal lines in astig- matism. S. M. Burnett. Abstract, vl 45 162 PHILOSOPHICAL SOCIETY OF WASHINGTON. Optics, List of papers on—Cont'd, why the eyes of animals shine in the dark. S. M. Burnett. Abstract and reference, vii 13 the Javal and Schiotz ophthalmometer. S. M. Burnett. Title only vlil 11 on a device for viewing the sun by light of any desired wave length. W. Hark- ness. Abstract x 13 Orange Mountain, N. J viil 19 Orbit of comet, Correction of ii 22 Hyperion x 90, 104 Swift's comet iv 59 Orbits illustrated by models x 28 of Titan and Hyperion Hi 2C, 40 Special case in elliptic vii 122 Ore deposition by replacement vi 32 Organization of the Society i v, 19, 20, 21 Orthocenter viii 47 Osborne, J. A., cited on the pupation of the Nymphalidse Hi 41 Osborne, J. W., communication on a new meteorological instrument. Abstract, ii 63 the study of meteorology in regard to the causes of yellow fever. Title only, Hi 21, 27 a curious manifestation of force by the wind. Title only Hi 27 a case of peculiar corrosive action on metallic tin. Title only i Hi 44 remarks on auroras iv 22 Otis, G. A., Biographical sketch of iv 171 Bibliography of. iv 181 communication on fractures of the inner table of the cranium. Title only 1 73 a new spirometer. Title only i 94 Death of. iv 120 Resolutions on the death of. iv 134 Ox-eye daisy as an insecticide vU 12 Pacific Ocean, Temperatures and currents of H192 Painting with dry colors viii 14 Paleontology. (See Zoology and Botany.) Palaeotherium, Structure and shape of. i 99 Pamphlets, Care of viii 29 Papers read to the Society. (See Acoustics, Anatomy, Anthropology, Archaeology, Astronomy, Biography, Biology, Botany, Calendars, Chemistry, Electricity, Geog- raphy, Geology, Mathematics, Meteor- ology, Microscopy, Mineralogy, Miscella- neous, Oceanography, Optics, Physics, Political Economy, Psychology, Seis- Page. mology, Social Science, Thermometry, Zoology.) Statistics of the Society's x 32 Papyrus Ebers ii 64 Parallax of aTauri x 91 Methods of measuring v 39 Parker, Peter, communication on the me- teor of December 24, 1873. No ab- stract i 94 Joseph Henry. In full ii 368 remarks on Chinese vocabularies ii 28 calendars ii 30 electrical treatment ii 40 origin of the American Indians ii 94 report of the committee to collect infor- mation relative to the meteor of De- cember 24th, 1873. In full. Map and 2 figures ii 139 resolutions on the death of Salmon P. Chase i 87 Patterson, H. N., cited on the flora of Illi- nois iv 99 Paucker, Prof. M. G., cited on Malfatti's problem H 116 Paul, H. M., communication on earth trem- ors as shown by astronomical observa- tions. Abstract Hi 120 problems connected with the physics of the earth's crust. Title only viii 17, 18 the Flood Rock explosion. Title only, viii 28 the Charleston earthquake. Abstract.Xx. 41 remarks on sun glows vH 35 earthquakes vii 73, ix 42 the topophone viii 13 dry painting by the Japanese viU 16 time determinations viii 58 graphics x 5 Pavements, Failure of wooden ii 26 Peale, T. R., Death of. viii 10 Peirce, Benjamin, cited on curves similar to their evolutes vii 87 communication on the heat of the sun. Abstract i 31 the theories of the nature of comet's tails. Reference i 74 Death of. It 21, 23 Remarks commemorative of iv 23 Resolutions on death of. iv 23 Peirce, C. S., cited on verification of predic- tions vii 124 communication on the appearance of Encke's comet as seen at Harvard Col- lege Observatory. Reference i 35 stellar photometry. Reference i 63 INDEX TO VOLUMES I-X. 163 Page. Peirce, C. S., communication on—Cont'd, the coincidence of the geographical dis- tribution of rain fall and illiteracy, as shown by the statistical maps of the ninth census reports. Abstract i 68 logical algebra. Reference i 88 quaternions, as developed from the gen- eral theory of the logic of relatives. Title only i 94 various hypotheses in reference to space. Title only i 97 Peirce's criterion , vi 155 Pendulum formulae vii 89, 101 Perception of color, form, and light vii 72 Periodic integrals .x 100 law of the chemical elements vii 15 Permian formation of North America. ..iii 67, 104 Persian calendar ii 38 Perturbations of moon's motion, Computa- tion of -vi 136 Polyhymnia by Jupiter Tiii 54 Peru, Meteorology of ii 35 Peters, Prof. C. H. F., cited on supposed trans-Neptunian planet Hi 20 letter on transit of Venus, 1874. Commu- nicated by A. Hall. Abstract ii 31 Petrographic methods vii 36 Phenomena, Physical basis of. vii 40 Philosophical Society of Washington viii xlv Growth of x 47 why this name wai chosen i v, x 45 Phonetic alphabet ix 17 Phosphorescent clocks iii 33 Phosphorus and cerebral activity v 75 Photo-engraving i 41 Photographic panorama v 21 Photographing the sun's corona iii 117 transit of Venus, 1882 vi 21 Photographs of transit of Venus, 1874 ii 31 Photography as an aid to astronomy i 28 an aid to research i 41 Composite vii 25 Photometry, Stellar i 63 Photophone iv 143 Phthisis ii 124 Physical geography. (See Geography and Geology.) Physical-geographical divisions of the south- eastern portion of the United States, lx 22 Physical investigations by Joseph Henry..ii 271 method in intellectual sciences vii 18 Physics, List of papers on (see also Acous- tics, Optics, Electricity) : on the nature and origin of force. W. B. Taylor. Abstract and reference i 27 Page. Physics, List of papers on—Cont'd. on the fatigue of metals. Major King. Title only i 53 on waves, molecules, and atoms. W. B. Taylor. Abstract i 66 on the rectilinear motion of a particle toward an attracting centre. A. Hall. Reference i 88 on the motion of a particle towards an at- tracting centre. H. H. Bates. Title only i 89 on the nature of the force of gravitation. R. Keith. Title only i 89 on a method of developing magnetism in bars of steel. J. Henry. Title only, i 97 on the movement of a particle attracted towards a point. H. H. Bates. Ab- stract ii 19 a method of determining a definite inter- val of time, and its application to meas- uring the number of vibrations of solid bodies. A. M. Mayer. Title only ii 64 Crookes' radiometers. J. Henry. .46- stract _ ii 80 force and momentum. E.B.Elliott. Title only ii 84 a thermodynamic theory of the spectrum. S. Newcomb. Title only iii 41, 43 vortex motion in ordinary fluids. T. Craig. Reference iii 143 curious fallacy as to the theory of gravita- tion. B. Alvord. In full v 85 on physics and occult qualities. W. B. Taylor. Presidential address. In full, v 125, 126 the three methods of evolution. J. W. Powell. Presidential address. In full, vi xxvii, 110 the nature of matter. H. H. Bates. Ref- erence vi 5 substance, matter, motion, and force. M. H. Doolittle. Title only vi 14 the atomic philosophy, physical and meta- physical. J. C. Welling. Presidential address. In full vii xxix, 81 music and the chemical elements. M. H. Doolittle. Abstract vii 26, 27 review of the theoretical discussion in Prof. P. G. Tait's " Encyclopaedia Brit- annica" article on mechanics. H. Farquhar. Abstract vii 29 the physical basis of phenomena. H. H. Bates. Infull vii 40 a formula for the length of a seconds- pendulum. G. W. Hill. Reference..iril 101 164 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Physics, List of paper9 on—Cont'd, a slight modification of the Newtonian formula of gravitation. W. B. Taylor. Abstract viii 39 Can the attraction of a finite mass be infi- nite? C. H. Kummell. In full viii 58 Newton's vis. M. H. Doolittle. Title only, x 38 the free cooling of a homogeneous sphere initially heated to a uniform tempera- ture. R. S. Woodward. Reference x 90 the conditioned cooling of a homogeneous sphere. R. S. Woodward. Reference.* 103 Physics of the Mississippi river i (13) Piedmont region ix 24 Pile of balls Hi 76 Piles bored by teredo v 98 Pisciculture x 55 Plains, Artesian wells on the v 101 Plane curves, Contact of vi 157 Planet, Centre of apparent disk of ii 181 search for intra-Mercurial ii 85 supposed discovery of a trans-Neptunian, iii 20 Planetary mass determined from two satel- lites vi 132 motion as affected by meteoric matter, ii 18S, 189, 190 motions iii 26, vi 41 perturbations of the moon vi 136 Planets, Theory of iv 57 Plants, Climate of. ii 183 on Roan Mountain.. iv 03 Plateau region .• i 55, vii 76 Plato cited on philosophy.. vii xxxvi Plethysmographs v 77 Pleurotomaria, Notch in shell of. iii 70 Plover Bay, Alaska ..iv 124 Plucker, Prof. J., cited on Malfatti's problem ii 118 Plumb-line deflection. ..ii 82, vii 92, 101, ix 15, 53 Poggendorf corrections in thermometry...ix 29 Poinsot, Louis, cited on impact of inelastic bodies v 131 Poisoned arrows ii 180, 1S2 Poisson cited on temperature of space ii 7:; Polar expedition ii 89 Polaris expedition i 92 Polarization of light by a narrow slit.iii 119, 124 Pole, Shifting of the earth's viii 10 Political Economy, List of papers on ; on the statistics of the borrowing power of the United States. E. B. Elliott. Title only i 29 on international coinage. E. B. Elliott. Tifa only 1 75 Page. Political Economy, List of papers on — Cont'd. [change in value of dollar.] E. B. Elliott. No abstract i 91 on the credit of the United States, as shown by the value of its securities. E. B. Elliott. Title only 1 109 on the transition in Germany, and the Scandinavian nations of Sweden, Nor- way, and Denmark, from the silver standard of coinage and money of ac- count to a gold standard. E. B. Elli- ott ii 25 the mutual relations as to price of gold, silver bullion, silver coin, and green- backs. E.B.Elliott. Title only ii 50 mutual relation as to price of gold, green- backs, silver bullion, and silver coin. E.B.Elliott. In full ii 52 two propositions, now before Congress, for changing the coin of the United States. E. B. Elliott. Title only ii 68 monetary standards. E. B. Elliott. Title only ii 85 mutual relations of gold and silver, and of prices of commodities. E. B. Elliott. Abstract ii 87 optional monetary standards. E. B. Elli- ott. Title only ii 135 the progress of international coinage in France and America. E. B. Elliott. Title only iii 27 the subject of international coinage. E. B. Elliott. Abstract iii 38 the silver question. C. E. Dutton. In full iii 78 the silver question. Symposium. Ab- stract iii 107 the construction of the Government sink- ing fund. E. B. Elliott. Abstract...lU 113 the principles of taxation. S. Newcomb. Title only iii 119 the distribution of loans in the Bank of France, the national banks of the United States, and the Imperial Bank of Germany. J. J. Knox. Abstract, iv 31 [bi-metallism.] E. B. Elliott. Abstract, iv 141 accrued interest on Government securi- ties. E.B.Elliott. Title only v 21 on the credit of the United States, past, present and prospective. E.B.Elliott. Title only v 102 on some formulae relating to Government securities. E. B. Elliott. Title only..jv 106 INDEX TO VOLUMES I-X. 165 Page. Political Economy, List of papers on— Cont'd, the distribution of tho surplus money of the United States among the States. J. J. Knox. Abstract vi 103 a financial problem. E. B. Elliott. Title only vi 149 annual profit to banks of national bank note circulation. E. B. Elliott. Title only ix 14 quantity of United States subsidiary silver coin existing and in circulation. E. B.Elliott. Title only ix 14 Polyhymnia, Perturbations of. viii 54 Poncelet, cited on Feuerbach's circle....viii 45 Population, Animal, of the globe iv 27 of the earth lv 28 Westward movement of i 35 Porter, communication on recent ex- plorations in Syria under the auspices of the Palestine Exploration Fund. Title only i 54 Porter, Miss S., cited on the instruction of the deaf. vi 81 Porter, R. P., cited on statistics of sheep...lv 28 Portrait of S. F. Baird x 41 of Joseph Henry 11 frontispiece. Potato rot 1 97 Pouillet, cited on temperature of space. ....11 73 Pouillet's formula for rate of cooling v 91 Powell, J. W., communication on the struct- ural geology of the valley of the Colo- rado of the West. Abstract 1 48 the mythology of the Numas. Refer- ence 1 96 the genesis and demonology of the Numa tribe of Indians. Reference 1 104 the UiDtah Mountains. Title only 11 34 the causes of the glacial climate. Ab- Stract 11 44, 45 some types of mountain building. Title only 11 65 monoclinal ridges. Abstract 11 74 life of Archibald Robertson Marvine. In full 11 83, (53) geologists versus physicists. No abstract, 11 85 the philosophy of the North American Indians. Title only 11 109, 110 poisons among the North American In- dians. Abstract 11 182 the lands of the arid region of the United States. Abstract 11 189 the evolution of language. Title only..ii 199 limitations to the use of some anthro- pologic data. Reference iv 134 Page. Powell, J. W., communication on—Cont'd, the three methods of evolution. Presi- dential address. In full vi xxvii, 110 plan for the subject bibliography of North American geologic literature. Title only vii 71 the personal characteristics of Professor Baird. In full x 71 remarks on auroras 1 48 volcanism in Arizona and Nevada 1 99 distribution of volcanic action 1 102 the vocabulary of the Utes 11 28 ripple marks 11 62 khivas 11 66 landslip lakes 11 69 interior of the earth 11 79, 85 aboriginal historical charts 11 93 fallacies concerning Indians ....11 180 mounds as evidence of population 11 181 western Permian strata ill 106 organization of primitive society ill 137 plants of Washington and vicinity iv 119 auroras lv 22 uniformity of peak altitudes in the Ap- palachians lv 64 force and vital principle v 104 eruption and elevation vi 92, 93 drainage system of Iowa vi 97 glaciers vii 8 distribution of volcanic eruption vii 79 Precession and terrestrial rigidity 11 77, 78 Precipitation measured at different heights, 11 49 Preece, cited on photophonic experiments, lv 149 radiophony lv 183 Predictions of weather and their verifica- tion vii 122, vili 8 Presidential address. See Address. Pressure and temperature, Diurnal changes of 11 67, 69 Prevost's theory of exchanges v 140 Prico, cited on infinite attraction viii 58 Price-Edwards E., cited on refraction of sound iv 137 Prices of gold, greenbacks, and silver 11 52 Probabilities, Meteorologic v 122 Problem concerning spheres v 107 Financial , vl 149 in hydrostatics vii 92, 101, ix 15, 53 probabilities x 87, 89 Problems in geometry Hi 55, 64, v 88, 107, vi 157, viii 45, x 96 Proctor, Richard, cited on the zodiacal light, i (20), (22) Prodromus Methodi Mammalium 11 (3) 166 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Prognostication for the winter of 1882-83....v 122 Proorthode , vi 123 Protagon v 75 Protoplasm, Possibilities of v 102 Psychical research x 8 Psychology v 72 Psychology, List of papers on : on logical algebra. C. S. Peirce. Refer- ence i 88 on the number of words used in speaking and writing. E. S. Holden. In full, ii 28, (1G) unconscious cerebration. E. M.Gallaudet. Title only ii 48 dreams in their relation with psychology. E. J. Farquhar. Abstract vi 37 the atomic philosophy, physical and meta- physical. J. C. Welling. Presidential address. In full vi! xxix, 81 the application of physical methods to* in- tellectual science. R. D. Mussey. Ab- stract vii 18 Are there separate centers for light-, form-, and color-perception ? S. M. Burnett. Abstract and reference...... vii 72 recent experiments on reaction time and the time sense. G. S. Hall. Title only viii 4 modern ideas of brain mechanism. P. Baker. Title only viii 17 anthropometric and reaction-time appa- ratus. J. S. Billings and W. Matthews. Abstract viii 25 an attempt at a theory of odor. F. W. Clarke. Abstract viii 27 the frequency of coincidences. L. F. Ward. Abstract x 8 Psychrometer, Sling viii 25 Publication of mathematical papers. ..vi 115, 135 of bulletin. See Bulletin. Publications of scientific societies. ..viii xxxvii the Philosophical Society x 114 Pumpelly, Prof. R., Researches on sewage in soils by iv 38 Pupation of the Nymphalidse iii 41 Pyrethrum puwder vii 10 Pythagorean philosophy vii xxxiii Quadrature of circle i 57 Quadratures, Approximate ii 48 Quadric transformation of elliptic integrals, vii 102 Quaternary climate of the Great Basin v 21 deposits of western Iowa and eastern Ne- braska iv 120 of the middle Atlantic slope x 16 Page. Quimby, Prof., cited on the aurora of Feb. 14, 1872 i 48 Quotients of space-directed lines x 105, 106 Radcliffe, C. B., cited on muscular contrac- tion .-. v 59, 61 Radiometer ii 80 Radiophony iv 143, 183 Railroad levellings and their hypsometric value ii 23 trains, Resistance of iii 29 Rain-fall and illiteracy i 68 Rain-gauges at different elevations ii 49 Rainier and its glaciers x 10 Ramsey, , letter on the tides of the Bay of Fundy. Communicated by J. J. Wood- ward. Title only i 94 Rankine, W. J. M., cited on reconcentration of energy v 172 Ratio of circumference to diameter i 57 Ravenfi, Gustave, communication on the as- teroids. Title only viii 18, 54 the theory of Mercury. Abstract viii 41 Rayleigh, Lord, cited on sound produced by heat iv 150, 183 Raymond, C. W., communication on the re- sults of travels in Alaska and the de- termination of the position of Fort Yukon. Communicated by T. L. Casey. Reference i 22 letter on transit of Venus, 1874. Commu- . nicated by A. Hall. Abstract ii 31 Reaumur cited on the pupation of the Nym- phalidte iii 41 Reed, Henry, communication on the physi- ology of civilization. Title only ill 20 Reference indexing x 38 Refraction in the principal meridians of a triaxial ellipsoid vi 4 of sound ii 57, 167 (48), v 35, 39, 44 Uncertainty of correction for atmos- pheric i 69 Rejection of doubtful observations vi 152 Religion and science ii 16, 224 Removal of place of meeting x xxxi, 10, 31 Remsen, Prof. Ira, Researches on impure air by iv 37 Report of committee to collect information relative to the meteor of December 24th, 1873 ii 139 Representation of comet orbits by models, x 28 Research, Endowment of. viii xli Method of ii 163, iv 40, vii li, x 4 Resistance of railway trains iii 29 Resisting medium in space 134, 39 INDEX TO VOLUMES I-X. 167 Page. Resolution on acceptance of membership, ill 149 auditing committee v 84 committees on mathematical papers..vi 135 discovery of the satellites of Mars ii 186 resigned and dropped members v 84 the title "Mr." i 104, x 46 providing for presidential address iv 30 Resolutions of the International Geodetic Commission on unification of longi- tudes and time vi 107 on the death of L. Agassiz i 94 B. Alvord vii 127 S.P.Chase i 87 B. F. Craig ii 130 J. Henry ii 196 J. H. Lane iii 123 A. R.Marvine ii 83 A. J. Myer.., iv 31 G. A.Otis iv 134 B. Peirce iv 23 J. Rodgers v 105 G. C. Schaeffer i 90 J. J. Woodward vii 75 Review of Tait's article on mechanics vii 29 Reynolds, Prof., cited on refraction of sound, ii 58, v 40, 44 Rhymes, Counting out x 13 Richardson, J. G„ communication in regard to the diagnosis of blood-stains. Read by J. J. Woodward. Reference ii 41 Riddell, Dr. J. L., Discovery in microscopy by iv 35 Ridges, Monoclinal ii 74 Ridgway, Robert, cited on Baird's " Birds of North America" x 65 communication on a natural arrangement of the Faleonidse. Read by T. Gill. Reference ii 41 Rigidity of the earth ii 76 Riley, C. V., communication on the pupation of the Nymphalidse. Abstract iii 41 the issuance of silk worms from their cocoons and some striking departures from normal habits in insects. Title only iii 44 recent advances in economic entomol- ogy. Abstract vii 10 the systematic care of pamphlets. Ab- stract viii 29 our city shade-trees, their foes and their future. Reference x 7 Riley, J. C, Death of iii 28 Rings of Saturn ii 94, 102, 188, vi 41 Ripple marks ...ii 61 Ritter, J. W., cited on the chemical rays...v 135 Page. Ritter, W. F. McK., communication on a simple method of deriving some equa- tions used in the theory of the moon and of the planets. In full iv 57 secular perturbations of Polyhymnia by Jupiter. Abstract viii 54 Rivers and terrestrial rotation vii 21 of Iowa vi 93 Roan Mountain iv 60 Robinson, J., Flora of Essex Co., Mass., by iv 95 Robinson, T., communication on the strata exposed in the east shaft of the water- works extension. Abstract vii 69 Was the earthquake of September 19th [1884] felt in the District of Columbia ? Abstract vii 73 remarks on deflection of rivers vii 24 measuring earth tremors viii 28 Robison, Prof. J., cited on elasticity v 132 Newton's rings v 155 Rochester tornado vii 3 Rockwood, C. G., communication on the Charleston earthquake. Abstract. ..ix 37 Rodgers, John, Death of. v 102, 105 Rogers, Prof. H. D., cited on the Devonian in Pennsylvania 11 (34), (38) Rogers, Prof. W. B., cited on geology at Sul- phur Springs, W. Va ii (27), (30) Rogers' rulings on glass ii 130 Ross, A. C, communication on latent im- pressions on polished glass pjates pro- duced by heating the plates in close connection with engraved metal lie- plates. Abstract ii 39 Rotation and rivers vii 21 in office v 49 Rowland, cited on thermometry ix 30 Riicker, Prof. A. W., cited on the constant P, x 102 Rule on communications from sections...vi 38 Rules for Publication of Bulletin. See Bulletin. Standing. See Standing rules. Rulings on glass ii 130 Rumford, Count, cited on theories of heat..v 133 Russell, I. C, communication on the exist- ing glaciers of the High Sierra of Cali- fornia. Abstract and reference. 2 fig- ures vii 5 deposits of volcanic dust in the Great Basin. Abstract vii 18 What is a glacier? Abstract vii 37 the faults of the Great Basin and of the eastern base of the Sierra Nevada. Abstract ix 5 168 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Russell, I. C, communication on—Cont'd, the subaerial decay of rocks and the origin of the red clay of certain forma- tions. Title only ix 16 Russell, Thomas, communication on tem- peratures at which differences be- tween mercurial and air thermometers are greatest. In full. I figure lx 25 normal barometers. Title only ix 46 Russian meteorology i 75 Rutherford, cited on computation of tt i 58 Sabine, Gen., cited on Plover Bay iv 125 St. George Island, Seals on i 91 St. Louis directrix, Altitude of ii 24 St. Paul Island, Seal3 on i 91 Salinometer ii 185 Sand sculpture i 57 Sanderson, Dr. Burden, cited on bacteria..ii 109 Sands, B. F., Death of„ vi 41 Sandwich Islands, Geology of. vi 13 Satellites, Computations concerning vii 93 of Mars ii 181, 186, 188, 190, vi 45 Saturn iii 26, 40 Uranus- i (30) Saturday-NightClub x 45 Saturn and its rings, Revolution of ii 188 Bright spot on ii 102 Rings of ii 94, 102, 188, vi 41 Satellites of. iii 26, 40 Shadow of. ii 102 Saville, J. H., communication on the new Japanese coinage. Title only i 51 Sawyer, C. J., communication on the Signal Service bibliography of meteorology and terrestrial magnetism. Head by C. Abbe. In full x 23 Schaeffer, G. C, Resolutions on the death of. i 90 Schellbach, Prof. K. H., cited on Malfatti's problem ii 118 Schools of Japan ii 69 Schott, C. A., communication on a new eye- piece for observing personal equations. Title only ii 200 the secular change in the magnetic de- clination in the United States and at some foreign stations. Abstract iii 45 remarks on calendars ii 38 rigidity of the earth ii 77 Sciences, Philosophic order of. v 105 Present state of ii 16 Progress of. ii 56 Scientific administrators ;.ix xliii experimentation ii 163, vii li Page. Scientific men and their duties ix xxxv Distribution of. ^. x 7 method ii 163, vi xxxiii, vii li and social progress- iv 40 societies i vi, viil xxxiii of Washington, and Professor Baird x 45 of Washington, Proposed federation of, v 102 of Washington, Statistics of x 29 work by state aid viii xli Scrope, G. P., cited on columnar structure, Viii 24 Sea level influenced by winds and baro- metric pressure i 53 Seals, Fur-bearing i 91 Secchi, Angelo, cited on elasticity v 130 Saturn's rings vi 43 Seconds-pendulum formula vii 101 Secretaries' report...vi 111, vii xxiii, viii xxvii, ix xxix, x xxxii Secular change in magnetic declination. ..iii 45 perturbations of Polyhymnia by Jupiter, viii 54 Seebach's method of determining earth- quake foci x 17 Seitz, E. B., cited on Malfatti's problem ii 118 Seismology, List of papers on : on the earthquake phenomena recently experienced in North Carolina. T. L. Clingraan. Abstract and reference i 104 earth tremors as shown by astronomical observations. H.M.Paul. AbstracL.itl 125 earth vibrations at Niagara Falls. J. M. Toner. Abstract iv 186 seismographic record obtained in Japan. E.Smith. Title only vi 87 Was the earthquake of September 19th [1884] felt in the District of Columbia? T.Robinson. Abstract vii 73 the Flood Rock explosion. F. W. Clarke, C. F. Marvin, and H. M. Paul. Ab- stract viii 28 the Charleston earthquake. Symposium. Abstract. Map ix 37, 38 a recent visit to the scene of the Charles- ton earthquake and resulting conclu- sions. C. E. Dutton. Title only x 16 on the depth of earthquake foci. C. E. Dutton. Title only x 17 the speed of propagation of the Charleston earthquake. C. E. Dutton and S. New- comb. Reference x 28 Series for determining the ratio of circum- ference to diameter i 57 Serpent venom vi 38 Sewage in soils iv 38 INDEX TO VOLUMES I-X. 169 Page. Sexes, Disparity of, in mollusks ill 75 Shade trees and their foes x 7 Shanks, cited on computation of t 1 58 Shasta, Mount x 10 Shastina, Volcanic sand from vii 33 Shell heaps of the Aleutian islands it 65 Shelters for thermometers vi 46 Sherman, W. T., communication on a visit to Egypt. No abstract i 63 travels in Turkey and the Caucasus. No abstract i 65 Sherman, Wyoming, as a site for an astron- omical observatory i 70 Shields, C.W., communication on the present state of the sciences. Abstract and references ii 16 the philosophical order of the sciences. Reference v 105 Shoes, high-heeled v 117 Shoulder girdle of fishes i 64 Shrinkage cracking in basalt viii 20 Siberia-Alaska boundary iv 123 Sibscota, G., cited on dumbness aud deaf- ness vi 49 Side-coefficients, Removal of. viii 41 Siemens, C. W., cited on conservation of solar energy v 172 Sierra Nevada, Geology of. ix 4, 5 glaciers vii 5 Sign language vi 63, 84 Signal Service bibliography of meteorology, x 20, 23 Silver coin, Quantity of. ix 14 Silver-gold ratio iv 141 Silver question, The, iii 78, 107 Similar inventions in areas widely apart, ix 12 Sinking fund, The United States iii 113 Siren 1185,(51) Skinner, A. N., communication on the pre- cession of stars in right ascension. Title only ill 21 Sling psychrometer viii 25 thermometer vi 46, vii 80 Smart, Dr. Chas., Researches on food adult- eration by iv 39 Smith, Edwin, communication on a seismo- graphic record obtained in Japan. Title only vi 87 Smithsonian bonds of State of Arkansas...vi 105 edition of the Bulletin x 113 Smithsonian Institution under administra- tion of S.F. Baird x 49 under administration of Joseph Henry, ii 285 Bnake venom vi 38 \ Page. Social evolution vi xlviii progress and scientific method iv 40 Social Science and Statistics, List of papers on : on the adjustment of census returns. E. B.Elliott. Title only 1 63 on the coincidence of the geographical distribution of rainfall and of illiter- acy, as shown by the statistical maps of the ninth census reports C. S. Peirce. Abstract* 1 '68 on life and annuity tables, based on the census of 1870. E. B. Elliott. Title only 1 74 on the use of metric weights and balances for postal purposes in the United States. E. B. Elliott. Abstract 11 15 further remarks on metric weights and balances for the postal service. E. B. Elliott. Abstract 11 19 on proposed reforms in spelling the Eng- lish language. A. R. Spofford. Title only..., 11 42 the mortality among army officers. B. Alvord. Reference Ii 49 [proposed governmental insurance.] B. Alvord. No abstract ii 49 [a statistical diagram.] E. B. Elliott. No abstract ii 134 animal population of the globe. L. F. Ward. Abstract.... iv 27 the relation of scientific method to social progress. S. Newcomb. Presidentivl address. In full iv 40 the international convention of the teach- ers of the deaf and dumb, at Milan. E. M. Gallaudet. Abstract iv 55 mortality statistics of the Tenth Census. J. S. Billings. Abstract Iv 163, 164 on survivorships, with tables and formulas of construction. E. B. Elliott. Title only v 122 fallacies concerning the deaf, and the in- fluence of such fallacies in preventing the amelioration of their condition. A. G. Bell. In full vl 48 the vital statistics of the Tenth U. S. Cen- sus, J.S.Billings. Reference viii 4 a fonetio sslfabet. H. Farquhar. Abstract. ix 17 the geographical distribution of scientific men and institutions in the United States. G. B. Goode. Reference x 7 the economic phase of the English spar- row question. C. H. Merriam. Refer- ence x 16 170 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Social Science and Statistics, List of papers on—Cont'd, statistics of the Philosophical Society from its foundation. G. K. Gilbert. Ab- stract ...x 29 the progress of science as exemplified in the art of weighing and measuring. W. Harkness. In full x xxxvii, 39 association ratios. M. H. Doolittle. Ab- stract x 83 association ratios. M. H. Doolittle. Ab- stract x 94 Societies, American scientific vlii xxxiii Scientific 1 vi and Professor Baird x 45 Statistics of x 29 Soils and sewage lv 38 Solar corona 1 31, 111 110, 121 eclipse, Jan. 11, 1880 ill 121 July 29, 1878 11 202, 111 116 heat variations and climate vi 10 parallax derived from transit of Venus, 1874 lv 168 from the velocity of light Hi 74 methods v 39 Solid, liquid, and gas defined v 136 Somoff 's theorem ix 54 Sondhauss, cited on refraction of sound. ...11 57 Sorghum sugar ill 140 Soul v 103 Sound, Abnormal phenomena of. 11 37 and fog signals 11 57, 60, (45), lv 135, v 23, 39 heat iv 143, 183 light iv 143 Determination of direction of...ill 69, viii 12 from two syrens ii 85 Joseph Henry's researches on ii 344 Refraction of ii 57, 167, (48), v 35, 39, 44 velocity and air temperature vi 47 waves and earthquake waves ix 42, 43 (See also Acoustics.) Sounds accompanying and following meteor of December 24, 1873 ii 157 South Mountain fault vi 30 Space vli 56 Resisting medium in 1 34, 39 Temperature of. ii 73 Space-directed lines x 105, 106 Sparrows, English x 16 Specific gravity method vi 26 Spectrophone _ iv 143, 101 Spectrum of Pneke's comet i 34 corona Hi 117 Speech, Visible iv 55, vi 60 Speed of propagation of the Charleston earthquake... x 17, 28 Page. Spencer, Herbert, cited on ceremonies ix 20 growth of crystals.* v 67 motion vii 57 nerve currents v 62 the ultimate v 164, 166 Spheres, Problem concerning v 107 Spheroid, Distances on any viii 52 Spofford, A. R., communication on proposed reforms in spelling the English lan- guage. Title only 11 42 Spontaneous generation ii 109, ^» 64, 103 Standard for micrometry Hi 22 Standard time ii 137, 202, vi 106 adopted by the society vii 18 A system of v 112 Standards of declination ix 53 length ii 136 value ill 78, 107 Standing rules of the General Committee, i xvii, il vi, ill vi, 149, lv 11, v 11, vi xii, vii xii, vili xii, ix xii, x xii Standing rules of the Mathematical Section, vl 115, vii 85, viii 35, ix 51, x 81 Standing rules of the Society..i xvi, li iv, Hi iv, 149, iv 7, 30, 38, v 7, vi ix, vii ix, viii ix, ix ix, x ix Star catalogue prepared at U. S. Naval Ob- servatory i 74 New ix 14 Stars, Arrangement of HI 76 Images of. ix 15 Station errors H 82 Statistics. (See Social Science.) Steam as a disinfectant Hi 51 Steiner, Prof. J., cited on Malfatti's problem, ii 115 on Feuerbach's circle vili 46 Stellar photometry i 03 Steno, cited on crystallography i 77 Sternberg, Dr. G. M., Researches on Bacillus malarise iv 39 Stokes, Professor, cited on refraction of sound H 58, (47), v 40 Stone, Ormond, communication on the de- termination of the errors of a pro- visory catalogue of fundamental stars. Title only i 02 the correction of a comet's orbit. Refer- ence H 22 a problem in probabilities. Abstract...x 89 the orbit of Hyperion. Abstract and ref- erence x 104 Stoneham, Me., Topaz from vili 5 Stoney, cited on the radiometer H 81 Storage of electric energy v 46 Storm centres, Movement of. i 99 INDEX TO VOLUMES I-X. 171 Page. Storm centres, Retardation of. v 108 Storms and auroras i 45 Law of i 106 Thunder ii 189 Storr, Dr. G. C. C, cited on the classification of mammals li (3) Strata exposed in shaft of water-works ex- tension vii 69 Struve, Otto, cited on determination of planet's mass from observations on satellites vi 132 satellites of Uranus i (35) Saturn's rings vi 42 Stryker artesian well i 103 Substance vl 14, vii 41 Sugar beet culture and climate iii 142 from sorghum iii 140 Sumner, W. G., cited on bi-metallism iii S4 Sumner's method in navigation ii 105 Sun, Heat of i 31 viewed by light of any desired wave length x 13 Sun-glows vii 17, 35 Sun's apparent diameter i (3) corona i 31, iii 116, 121 Surplus, Proposal to distribute the vi 103 Sweeping mechanism iii 142 Swift, Dean, cited on the scientific crank, viii xl Swift's comet, Orbit of iv 59 Swordfish and its allies iv 162 Sylvester, J. J., communication on the theory of invariants. Title only ii 95 Trisection linkage of. x 99 Symbols, Archeologic ii 72 Symons, Prof. G. J., Bibliographic work of, x 21, 23 Symposium on the cause of the glacial cli- mate ii 43, 45 the silver question iii 78, 107 What is a glacier ? vii 37 the Charleston earthquake ix 37, 38 What is topography ? x 14 a problem in probabilities x 87, 89 Systems of mineralogy i 77 Taconic system of Emmons x 5 Tainter, S., Photophonic experiments by. iv 145, 150 Tait, Prof. P. G., cited on forcc.v 128, 152, vii 29 Talbot, H. F., cited on the history of Mal- fatti's problem ii 114 Talcott's method x 91 Target-shooting and the theory of errors..vi 138 Taxonomic terms of Storr ii (7) Taylor, F. W., Analysis by vii 32 Page, Taylor, W. B., communication on the nature and origin of force. Abstract and ref- erence i 27 the aurora. Abstract 1 43 our present knowledge of the planet Jupiter. Title only i 62 waves, molecules, and atoms. Abstract, i 66 a calendar proposed by a Persian astron- omer in 1079. Abstract ii 38 the causes of the glacial climate. Ab- stract ii 43, 46 acoustic refraction. Abstract li 57 the temperature of space. Abstract ii 73 Joseph Henry. A sketch of his scientific work. In full ii 203, 230 a panoramic photograph. Abstract v 21 the total lunar eclipse of June 11, 1881. Abstract v 90 a remarkable halo. Abstract v 112 physics and occult qualities. Presiden- tial address. In full v 125, 126 the rings of Saturn. Abstract vi 41 a case of discontinuity in elliptic orbits. Abstract vii 122 geological and physical theories. .46- stract viii 6 the crumpling of the earth's crust. Ab- stract and reference viii 18 slight modification of the Newtonian formula of gravitation. Abstract...viii 39 Professor Baird as an administrator. In full x 49 remarks on calendar reform ii 30 interior of the earth ii 76, 77 radiometer ii 80 planetary motions ii 1S8, 189 amplitude of light waves iii 120, 125 death of J. H. Lane iii 124 taboo iii 138 Henry's acoustic researches iv 140 radiophony iv 162 anomalies of sound v 37 binary arithmetic vi 4 sling thermometer vi 47 satellites' orbits vi 133 infinitesimals vi 135 sun glows vii 35 topophone viii 13 resolutions on the death of G.C. Schaeffer, i 90 Telephone, Exhibition of ii 67, 103 Comments on ii 111 Telephonic study of binaural audition iii 09 Telephote ii 102 Telescope for Naval Observatory i 02, 83 172 PHILOSOPHICAL SOCIETY OF WASHINGTON. Temperature and pressure, Diurnal changes of it 67, 69 Conditions determining v 91 distribution over the surface of the globe, i 96 Measurement of atmospheric vl 46 of sea water as related to winds on the coast of New Hampshire ii 17 brain v 75 space ii 73 the air vi 24 the human body i 31 (See also Meteorology and Thermometry.) Temperatures at which differences between mercurial and air thermometers are greatest ix 25 of the Pacific Ocean ii 192 Tenth census mortality statistics... iv 164 Teredo navalis v 98 Terrestrial magnetism, Bibliography of..x 23, 27 Constant P in observations of. x 102 Terquem, cited on Feuerbach's circle. ..viii 46 Texas Cross Timbers x 6 Thanhoffer, cited on the pulse v 77 Theatres, Burning of ii 95 Theology v 103 of the American Indians ii 176 Theory of errors vi 152 practically tested by target-shooting...vi 138 Thermal belts of North Carolina vi 11 Thermometry, List of papers on : on thermometers. B. F. Craig. Title only i 42 a method of verifying with exactness the indications of a thermometer. B. F. Craig. Title only i 43 a comparison of the thermometers used to determine the correction for atmos- pheric refraction at the U. S. Naval Observatory. J. R. Eastman. Ab- stract i 68 on the air thermometer of Prof. Jolly. J. E. Hilgard. Title only i 89 determining the temperature of the air. C. Abbe. Abstract vl 24 hygrometric observations. H. A. Hazen. Abstract vi 36 thermometer exposure. H. A. Hazen. Ab- stract vi 46 thermometer exposure. H. A. Hazen. Ab- stract vii SO the measurement of temperature at dis- tant points. T. C. Mendenhall. Title only _..viii 18 the condensing hygrometer and sling psy- chrometer. H. A. Hazen. Abstract..-viil 25 Pagt-. Thermometry, List of papers on—Cont'd, temperatures at which differences between mercurial and air thermometers are greatest. T. Russell. In full. 1 fig- ure ix 25 the gilding of thermometer bulbs. J. H. Kidder. Title only ix 33 effects of solar radiation upon thermome- ter bulbs having different metallic coverings. H. A. Hazen. Abstract. ..Ix 33 Thompson, Gilbert, communication on the physical-geographical divisions of the southeastern portion of the United States and their corresponding topo- graphical types. Abstract ix 22 What is topography? Abstract x 15 remarks on glaciers vii 8 Indian paintings viii 16 Thompson, Prof. S. P., cited on eleetricity..v 168 Thomson, Sir William, cited on rigidity of the earth ii 78 Sumner's method ii 107 Volt-meter of. viii 26 Thomson, William, communication on a new method for detecting and measur- ing the optical defects of the eye. Reference i 22 Three methods of evolution vi xxvii Throwing-sticks ix 13 Thunderstorms in 1884 viii 10 Electrical phenomena of ii 189 Tidal retardation and consequent crumpling, viii 19 Tides at Boston influenced by winds and barometric pressure i 53 Tillo, Col., cited on levellings in Asia ii 34 Time, A system of standard v 112 determination with a meridian transit..viii 55 globe iii 107 Standard U137, 202, vl 106 Titan and Hyperion iii 26, 40, x 104 Titicaca, Climate at Lake il 35 Todd, D. P., communication on solar paral- lax from the velocity of light. Refer- ence iii 74 a mechanical attachment for equatorial mountings to facilitate sweeping in right ascension. Abstract and refer- ence iii 142 the solar parallax as derived from the American photographs of the transit of Venus 1874, December 8-9. Abstract and reference iv 168 Todd, J. E., communication on quaternary deposits of western Iowa and eastern Nebraska. Abstract iv 120 INDEX TO VOLUMES I-X. 173 Page. Todd, J. E., remarks on charcoal in the drift iv 122 Toner, J. M , communication on a method of describing aud locating with ease the approximate positions of geo- graphical regions. Title only i 97 the burning of theatres and public halls. Reference li 95 a malformed dog. No abstract ii 185 earth vibrations at Niagara Falls. Ab- stract iv 186 coins and medals. Abstract v 22 remarks on care of pamphlets viii 29 Tonto Sandstone, Age of i 109 Topaz from Stoneham, Me vlii 5 Topographic map defined x 11 types in the southeastern States ix 22 Topography and geology of the Cross Tim- bers of Texas x 6 and structure x 7 defined x 14 Topophone viii 12 Tornado at Rochester, Minn vii 3 Torreya in Southern States and Japan ii 42 Townley, K., cited on transmission of sound, v 42 Transit flexures viii 27 Meridian viii 55 of Mercury ii 199 Mercury, May, 1878 lit 43 Venus, 1874 i 63, ii 31, 33, iv 168 Venus, 1882 vi 21 Trap of Orange Mt., N. J viii 24 Treasurer's report v 176, 180, vi xii, vii xxiv, viii xxviii, ix xxx, x xxxiv Tremors detected by astronomical observa- tions iii 120 Triangle, Formulae for the area of viii 37 Problem concerning iii 55 Trisection of angles x 96 Trouvelot, L., Drawings of nebulae by ii 51 Tucker, R., Solution of a geometrical prob- lem by iii 65 Tupman, , letter on solar eclipse. Com- municated by W. JIarkness. No ab- stract 4 56 Twining, W. J., Death of. v 102 Tyndall, John, cited on photophonie experi- ments iv 152 sound anomalies v 33, 41 heat absorption by the air v 94, 96 Introduction of i 65 letter on fog signals. Communicated by J.Henry. No abstract i 91 Uinta Mountains, Permian rocks of ill 106 Pago. Unalashka volcanic sand vii 33 Unification of longitudes and time vi 106 Uniformitaiianism viii 6 United States, Centre of population of. i 35 Geographic centre of. i 22 Urara v 62 Uranometria Argentina iii 122 Uranus, Satellites of i (30) Utah, Glacial epoch in i 84 Permian formation of. iii 68, 105 Ute language ii 28 Vacant offices, Filling of. ii 84, iii 53, v 112, vi 41, vii 36 Valentin, cited on mineralogy i 77 Valleys, Classification of. i 49 Values at different times ii 87 Relative, of gold, greenbacks, and silver, ii 52 Van Sant, , communication on a method of lighting gas-jets by electricity. No abstract i 56 Variations of latitude viii 10 Vauquelin, cited on mineralogy i 78 Velocity of earth tremors viii 28 earthquake waves ix 41. x 17, 28 Venom of serpents vi 38 Ventilation of the House of Representatives, v 99 Venus, Transit of, 1874 i 63, ii 31, 33, iv 168 1882 vi 21 Verification of weather predictions vii 122, viii 8, x 83, 94 Vertebrae, Cephalic i 26 Virginia, Fossil plants from ii (26) Visible speech iv 55, vi 53 Vision vii 72 Apparatus for testing iii 53 Vital principle 127,v50, 102 statistics of the tenth U. S. census viii 4 Vocabulary of an individual ii 28, (16) Volt-meter viii 26 Volcanic dust in the Great Basin vii 18 necks vii 78 problem, The vi 87 sands vii 33 Volcano, Latest, in northern California ix 46 Volcanoes of New Mexico vii 76 Von Cronstedt, cited on mineralogy i 78 Von Jherling, Dr. H., cited on the Chito- nidce ii 193 Vortex motion iii 143 . Vulcan, Search for ii 85 Wagner, cited on the sun's diameter i (4) Waite, ChiefJustice M. R., letter announcing the death of Joseph Henry ii 196 174 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Walcott, C. D., communication on the Cam- brian system in the United States aud Canada. Abstract. I figure vl 98 the geologic age of the lowest formation of Emmons' Taconic system. Refer- ence x 6 Discovery of Permian fossils by ill 68, 105 Wallerius, cited on mineralogy i 78 Walling, H. F., communication on topo- graphical indications of a fault near Harper's Ferry. Abstract vl 30 Ward, Lester F., communication on the nat- ural system of plants. Title only.M 186, 187 the origin of the chemical elements. Title only Ill 33 animal population of the globe. Abstract, Iv 27 field and closet notes on the flora of Washington and vicinity. Abstract.Xv 64 the organic corn pounds in their relations to life. Title only v 91 some physical and economic features of the Upper Missouri system. Refer- ence vil 20 the flora of the Laramie group. Refer- ence vlil 17 the frequency of coincidences. Abstract, x 8 the geographical distribution of fossil plants. Reference x 28 remarks on vital force v 105 Dismal Swamp vl 30 deflection of rivers vli 23 Indian observation of nature vil 74 care of pamphlets vlil 29 Warren, G. K., cited on abnormal phenom- ena of sound 11 (48) communication on the geological history of Lake Winnipeg. Abstract 11 27 Warner, A. J., communication on the silver question. Abstract Ill 112 Wasatch Mountains fault 11 103 Growth of 11 195 Washington a scientific centre... .1 xi, vlil xlvi, x 47 Flora of iv 64 Watershed of the Adirondack region ii 67, 82 Waterspouts in North Carolina ii 104 Watson, J. C, communication on the discov- ery of new planets having especial ref- erence to the asteroids. Title only... .1 53 Watson, Sereno, cited on the Great Basin flora iv 99 the classification of plants iv 108, 110 Wave lengths of light '. v 142 Waves, Earthquake x 17 Page. Waves, molecules and at»ms i 66 Weather forecasts v 122, vlil 8 Webb, Capt., cited on phenomena of sound, ii (40), (50) Weiss, Prof., cited on mineralogy i 78, 79 Welling, J. C, communication on the life and character of Joseph Heniy. In full 11 203 anomalies of sound signals. In full v 39 the atomic philosophy, physical and metaphysical. Presidential address. In full vii xxix, 81 eulogy on Gen. A. A. Humphreys. Ab- stract vii 4 remarks on vocabularies ii 2S drifting buoys vil 15 Indian observation of nature vil 75 Wells, D. A., cited on medium of exchange, iil 101 Wenham. cited on microscope apertures. .ill 19 Werner, cited on mineralogy 1 78, 79 Wernich, cited on contamination of air by sewage iv 38 What is a glacier? vil 37 Wheatstone's microphone, Modification of, iv 183 Whewell, Dr. W., cited on attraction v 161 Greek philosophy vii xxxviii White, C. A., cited on the loess of Iowa iv 121 communication on the evolutional history of the North American Unionidce. Title only ii 181 asymmetry in the form of the human cranium. Title only ii 190 the fresh-water shell-heaps of the in- terior rivers of North America. Title only ill 32 the subject of the Permian formation in North America. Abstract ill 104 artesian wells on the Great Plains. Ref- erence v 101 remarks on the relations of plants to geology iv 119 loess of the Mississippi valley iv 122 teredo .v 99 theory of permanence of oceans vi 93 drainage system of Iowa vi 97 White, Prof. I. C, Discovery of Permian fos- sils by iil 105 Whitfield, R. P., Observations on Limnsea by ill 75 Whitney, Prof. J. D., cited on geology of Great Basin i 56 Whitney, Prof. W. D., cited on individual vocabularies 11 (19) Wiebe, H. F., cited on thermometry ix 26 INDEX TO VOLUMES I-X. 175 Page. Wild, Prof., cited on thermometry ix 33 Williams, G. H., communication on the methods of modern petrography. Ab- stract vli 36 Willis, Bailey, communication on the topog- raphy and structure in the Bays Mountains, Tennessee. Reference x 7 development of a perspective map from a contour map. Title only x 9 Mount Rainier and its glaciers. Ab- stract x 10 remarks on geology of Cascade Mount- ains ix 8 Winchell, Alexander, communication on the progressive dispersion of mankind over the surface of the earth. Title only ill 32 Wind and hygrometry vl 30 railway traction iii 31 retardation of storm centres v 108 as related to barometric gradient i 106 velocity and pressure x 10 Winds and barometric pressure in relation to tides 1 53 as related to ocean temperatures on the coast of New Hampshire il 17 observed in balloon ascensions 1 35 on mountain slopes iii 38 Wind-wrought errors in barometric observa- tion v 91 Wind-vane, Theory of. x 9 Winlock, W. C, communication on comets II and III, 1884. Title only vtii 16 physical observations of Wolf's comet (1884, III). Abstract vlii 37 Winter of 1882-83, Prognostication for v 122 Woeikoff, Alexander, communication on the meteorology of Russia. Reference 1 75 the results of a recent determination of the elevation of the Caspian and Aral seas. Abstract 11 34 meteorological observations in Peru, and some meteorological conditions of that country. Title only 11 35 Wood, Dr. H. C, Researches on inoculation of diphtheria by lv 38 Woodbury process of photo-printing 1 42, 57 Wooden pavements, Failure of il 26 Woodward, J. J., communication on the al- leged hermaphrodite described by Drs. Accly, Blackman, aud Jackson. Abstract and reference 1 24 he desirability of reproducing photo- graphs of scientific objects, and espe- cially of magnified microscopical preparations, in a permanent form by Page. Woodward, J. J., communication on—Cont'd, some photo-mechanical method. Ab- stract 1 41 the use of monochromatic sunlight as an aid to high-power definition. Ab- stract and reference 1 47 the Woodbury photo-relief process. Ab- stract 1 57 spectra and spectroscopes. No abstract, 1 89 micrometrie writing on glass. Title only 1 93 the similarity between the red blood- corpuscles of man and those of certain other mammals, especially the dog; considered in connection with the di- agnosis of blood stains in criminal cases. Abstract and reference 11 20 the markings on Navicula rhomboides. Title only 11 69 the rulings on glass by Mr. Rogers, of Cambridge. Abstract 11 130 the modern microscope, Nobert's lines, and the attempts of others to con- struct them. Title only 11 25 diffraction phenomena in the field of the microscope. Abstract and refer- ence ii 60 the microscopical structure of wool. Title only ii 62 the Papyrus Ebers. Abstract 11 64 the use of photography in connection with the micrometer measurement of blood corpuscles. Title only ii 79 a simple device for the illumination of balsam-mouuted objects for examina- tion with certain immersion objectives whose "balsam angle" is 90° or up- wards. In full. 1 figure 11126 theapertometerof Prof. E. Abbe, of Jena, Germany. Abstract ill 18 a standard for micrometry. Abstract, ill 22 the oil-immersion objectives of Zeiss, and on convenient methods of obtain- ing oblique illumination for these and similar objectives. Abstract ill 25 a new apertometer for microscopic ob- jectives. Title only iii 37 some apparatus recently brought into use by the Medical Department of the Army for the examination of the eye. Abstract* ill 53 Riddell's binocular microscope—an his- torical notice. Abstract and refer- ence „ iv 35 176 PHILOSOPHICAL SOCIETY OF WASHINGTON. Page. Woodward, J. J., communication on—Cont'd. a biographical sketch of the late Dr. Otis. In full iv 171 modern philosophical conceptions of life. Presidential address. In full v 49 Death of. vil 72 remarks on malformed dog i 185 diagnosis of blood-stains ii 41 a new meteorological instrument il 64 poisoned arrows ii 180, 182 Resolutions on the death of vii 75 Woodward, R. S., cited on infinite attraction, viii 59 communication on the special treatment of certain forms of observation-equa- tions. Abstract vi 150 a concrete problem in hydrostatics pro- posed by Mr. G. K. Gilbert. Titleonly, vii 101 some practical features of a field time determination with a meridian transU. Abstract viii 55 the changes of terrestrial level surfaces' due to variations in distribution of superficial matter. Reference ix 15 the position and shape of the geoid as dependent on local masses. Reference, ix 53, 54 the free cooling of a homogeneous sphere initially heated to a uniform tempera- ture. Reference x 90 the conditioned cooling of a homogene- ous sphere. Reference x 103 remarks on deflection of plumb-line. ...vii 92 Grassmann's geometry viii 53 infinite attraction viii 63 problem in probabilities x 89 Wolf's comet (1884 III) viii 37 Wooiara _ v 62 Words in an individual vocabulary ii 28, (1C) Written language and speech iii 139 Wyandottes, Social and political organiza- tion of iii 137 Yards. Standard ii 136 Yarnall, Mordecai, communication on the general star catalogue prepared from the observations at the Naval Observ- atory since 1845. Reference i 74 Death of iii 28 Yeast ferment as an insecticide vii 11 Yellowstone expedition of 1870 t 21 valley vii 20 Young, C. A., cited on observations at Sher- man, Wyo i 71, 73 zodiacal light i (21) Page. Young, C. A., communication on the expe- dition to Pekin for observing the late transit of Venus. Abstract ii 33 Young, Dr. T., cited on superficial repul- sion v 155 theories of heat and light v 134 Young-Helmholtz theory of color iv 54 Ziwet, Alexander, communication onGras-s- mann's system of geometry. Reference. viii 53 remarks on problem in probabilites x 89 Zodiacal light i (19) Zoological work of S. F. Baird x 62 Zoology, List of papers on (See also Bi- ology) . on the characteristics and zoological rela- tions of man. T. Gill. Abstract i 24 on the number of the cephalic vertebrae. T. Hilgard. Reference i 26 on additions to the fish fauna of Massachu- setts, due to the researches of Prof. S. F. Baird, U. 8. Fish Commissioner. T. Gill. Reference i 29 on the tapir of the Andes and its allied forms. T.Gill. Titleonly i 39 on a tunny new to the American coast. T. Gill. Titleonly i 47 on the decrease of fish on the southern coast of New England. S. P. Baird. Reference i 52 on the homologies of the shoulder girdle of fishes. T.Gill. Reference i 64 on the Scombrocottus salmoneus of Peters. T. Gill. Title only i <;8 on the homologies of the arm in fishes, and the development of the humerus in ganoids. T. Gill. Title only 1 73 on the habits of the fur-bearing seals of the islands of St. Paul and St. George, Behring Sea. H. W. Elliott. Refer- ence I 91 on the primates and their relations to man. T.Gill. Titleonly i 96 on the structure and homologies of the limbs, especially in Aves. E. Coues. Title only i 96 on the structure and shape of Palseothe- rium. T.Gill. Abstract i 99 on the "Prodromus methodi mammal- ium " of Storr. T. Gill. Infull...U 15, (3) on the similarity between the red blood- corpuscles of man and those of certain other mammals, especially the dog ; considered in connection with the diagnosis of blood-stains in criminal INDEX TO VOLUMES I-X. 177 Page. Zoology, List of papers— Cont'd. cases. J. J. Woodward. Abstract and rtfcrence it 20 on the geographical distribution of mam- mals. T.N.Gill. Abstract ii 26 explanatory note on the diagnosis of blood stains. J. G. Richardson. Read by J. J. Woodward. Reference 11 41 outlines of a natural arrangement of the Falcon idee. R. Ridgway. Communi- cated by T. Gill. Reference 11 41 the microscopical structure of wool. J. J. Woodward and John Leconte. Title only 11 02 the markings on Navicula rhomboides. J.J.Woodward. Title only 11 69 shower of the Rocky-Mountain grasshop- pers. C. G. Boerner. Communicated by J. Henry. Abstract 11 87 the relations and sequences of the family Centrarchoides. T. N. Gill. Title only 11 113 the morphology of the antlers of the Cer- vidse. T. Gill. Abstract and reference, 11 135 some phases of the evolutional history of the North American Unionidee. C. A. White. Title only 11 181 a new species of Chimsera found in Amer- ican waters. T.Gill. Abstract 11182 [exhibition of malformed dog.] J. M. Toner. No abstract 11 185 the results of recent investigations into the natural history of the Chitonidse. W. H. Dall. Abstract 11 193 a fish found on the Florida coast. W. S. Abbey. Letter, read by C. Abbe. No abstract \ 11 202 the family of Ceratiids. T. N. Gill. Title only 11 202 notes on the museums and zoological gardens of northern Europe. W. H. Dall. Title only ill 19. 21 the artificial propagation of the cod. S. F. Baird. Abstract ill 29 the embryology of Lin^ula and the sys- tematic relations of the Braehiopods. W.K.Brooks. Title only ill 33 the muscles of the oyster. W. H. Dall. Abstract ill 30 Page. Zoology, List of papers on—Cont'd. pupation of the Nymphalidse. C. V. Riley. Abstract Ill 41 the issuance of silkworm moths from their cocoons, and some striking departures from normal habits in insects. C. V. Riley. Title only Ill 4t some recent observations on mollusks. W. H. Dall. Abstract ill 75 some remarkable instances of ingestion among fishes. T. N. Gill. Abstract.Hi UO animal population of the globe. L. F. Ward. Abstract lv 27 the swordfish and its allies. G. B. Goode. • Reference iv 1C2 on some peculiar features of mollusks found at great depths. W. H. Dall. Abstract v 90 on some peculiar ravages of the Teredo navalis. A. B. Johnson. Title only..-v 98 on the classification of the insectivorous mammals. T.Gill. In full v 118 the prevention of malarial diseases, illus- trating, inter alia, the conservative function of ague. A. F. A. King. Ab- stract vl 5 recent experiments on serpent venom. R. Fletcher. Reference vi 33 analogues in zoo-geography. T. N. Gill. Title only vl 41 ichthyological results of the voyage of the Albatross. T.N.Gill. Title only vi 48 recent advances in our knowledge of the limpets. W. H. Dall. Abstract vil 4 recent advances in economic entomology. C.V. Riley. Abstract vll 10 certain appendages of the mollusca. W. H. Dall. Reference vll 32 two remarkable forms of mollusks. W. H. Dall. Abstract and reference viii 5 the distribution of fishes in the oceanic abysses and middle strata. G. B. Goode and T. H. Bean. Title only...ix 22 our city shade-trees, their foes and their future. C.V.Riley. Reference x 7 the economic phase of the English spar- row question. C. H. Merriam. Refer- ence x 16 Zornow, Prof. A. R., cited on Malfatti's prob- lem 11 118 3* 3> > • z» 3D» > > > 35> 30> > > :*> :30» > 5 » ZJ»1> > > 38> ZJS> > > >i> *> 3> ,7» > > >>3> > > -> 3 > > > } > > > 3 3 > . _^> 5 > > ^ 3 ^3 H> ; 2 3 3 >' > ^ --> 3 3 :>3 :> > - >33 3 3} 33? 3 3 > > -^» t> 5g 3 a 5 <3V>:3 j> > >J3> ;»;3 > p v> ^2? > 5 »j3S» > > *» .^ > > >> 36> > > ^» SMITHSONIAN INSTITUTION LIBRARIES 3 9088 01421 4241 Eg 3 > :ja»B > 3> j> j> - 3> } 3 3 > >3 :» 3 > r> ~^;> > > > :> > > > 3> ** > .."> - = > > a 3» r> ^> •3 3> ""^> 3> 3 5 3 ?' S> 3» C-3> 3 -> ^*>3 . ^» ."3>O J> J> > 3»* »3 "S r» >2> 3 JO O 3>3 " J> ; >-£>?* s> . > > >. 3 o - >1> — 2>X2> -= 3>o ^ ^> 03 > > 3> ,\ ^ 3t> -** 3> ^ 3J> : • » ~ P3 > ^?>3 >0 p> > >> > > 3> > : ^>3» 3>> :> ) )." > J J>3 >3 D3 ^> >3 )3^3 >3 >3 > 3> J >2> > a, ? & » r > » -, S ' > 3> >- > a» jj >- a» » »>- > 3» S^ > a» >>> j 3 > j ' 3»- >, ^•'3 3?