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Ana fran Fete V4.0taoheb en, See 2 68-80> ~~ — eS a ae a ee ee , PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. From November 18, 1886, to ae 16, 1886. MOI. Nan: te eee eoaseeeesararee LONDON: IIARRISON AND SONS, ST. MARTIN’S LANE, Printers in Ordinary to Her Majesty. MDCCCLXXXVII. LONDON: HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN’S LANE. COON TE NPs VOL. XUI. —— £26 32> — No. 246. On Underground Temperatures ; with Observations on the Conductivity of Rocks ; on the Thermal Effects of Saturation and Imbibition ; and on a Special Source of Heat in Mountain Ranges. By Joseph Soe tremmmeteete ee Eno, BO OS. ES 2 eh ela dech an dvacean-odeconthntnnseetsomoet On the Agency of Water in Volcanic Eruptions ; with some Observations on the Thickness of the Earth’s Crust from a Geological Point of View ; and on the Primary Cause of Volcanic Action. By Joseph ere aummen VIS RAS), HGS.) Be. 9 CP late, 1), cosseeds scree wicsaneant edecbssacenveose No. 247. Preliminary Report on the Pathology of Cholera Asiatica (as observed in Spain, 1885). By C. 8. Roy, F.R.S., J. Graham Brown, M.D., &c., and Oe PNR SOP ORES NR I CE tre oo Gh Siac cag say eiea eA a vonacan sae teudsctredepoces acon ssinvess An Instrument for the Speedy Volumetric Determination of Carbonic Peete sya Wy tltiam Marcet, M.D., B.RS, (Plate 2)> scsctccsscosssliceseconeede Researches in Stellar Photography. 1. In its Relation to the Photometry of the Stars; 2. Its applicability to Astronomical Measurements of Great Precision. By C. Pritchard, F.R.S., Savilian Professor of PembespeMUR RED BME IT DS CRSEOEOE ge eee sacl oee gad se loectastitieen vicpssvubcstestaveuasdesnibacieane sees Contribution to the Study of Intestinal Rest and Movement. By J. 2D EDT TS) RN IBD OS IEE eer et Pa RR et CC On the Practical Measurements of Temperature. Experiments made at the Cavendish Laboratory, Cambridge. By H. L. Callendar, B.A, peerobane Ub berveitiy Collemes Crarit bend re! 516,525 1 200 ie. ceaeesanscoasentsssvsacnvetotves The Determination of Organic Matter in Air. By Professor Thos. Carnelley, D.Sc., and Wm. Mackie, M.A., University College, Dundee. Page Liss; 181 195 212 251 238 7S er eS Lv. No. 248.—WNovember 18, 1886. On the Method of Condensation in Calorimetry (Abstract). By J. Joly, B.E., Assistant to the Professor of Civil Engineering, Trinity eis. DOUBLE scoseeeserecescesorseccussessesisnoecetsansssecete 248 On the Specific Heats of Minerals. By J. Joly, B.E., Assistant to the — Professor of Civil Engineering, Trinity College, Dublin 2... Se 250 Note on a paper entitled “Ona New Form of Stereoscope” (‘ Roy. Soe. Proe.,’ vol. 40, p. 317). By A. Stroh © ...0:.2¢:26e 274 On the Intensity of Light reflected from certain Surfaces at nearly Perpendicular Incidence. By Lord Rayleigh, M.A., D.C.L., Sec. R.S. (Plate 3) 2... .cccsssessoensszadsecsatnesenealosie coosvteoessdsecasdnanceass gee 275 A Theory of Voltaic Action. By J. Brown (Plates 4 and 5) ......0. 294 The Coefficient of Viscosity of Air. Appendix. By Herbert Tomlinson, BD, ATS. cease bunts ascecave’ osetia ives geese: oneade sean e cotacse aSekeaxnanaitale c-ce rrr 315 November 25, 1886. Additional Evidence of the Affinities of the Extinct Marsupial Quadruped, Thylacoleo carnifex, Ow. By Sir Richard Owen, K.C.B., F.R.S. ........ 317 On the Structure and Life-History of Entyloma Ranunculi (Bonorden). By H. Marshall Ward; M.A., F.LS., Fellow of Christ’s College, Cambridge, and Professor of Botany in the Forestry School, Royal Indian Engineering College, Cooper’s Hull ”............ ...1-.-.-.ete ee 318 On Jacobi’s Figure of Equilibrium for a Rotating Mass of Fluid. By G. H. Darwin, M.A., LL.D., F.R.S., Fellow of Trinity College and Plumian Professor in the University of Cambridge ............ccsscesceencen sees 319 On the Dynamical Theory of the Tides of Long Period. By G. SEE Darwin, M.A., LI..D., F.R.S., Fellow of Trinity College and Plumian Professor in the Univer sity of Cam brid ge -2c..dcte..t.i02 soins er 337 ASG OF PKESCMUS 02.0... ceescedsccseuoanoon otnacegeccssasdbsctnes snteeeteont tans: 0 re 343 On the Method of Condensavion n Calorimetry. By J. Joly, B.E., Assistant to the Professor cf Civil Engineering, Trinity College, = Dublin (Plates 6.and 7) > 22.05.88... sccéececsssserisccecs kere teeceese one 352 No. 249.— November 30, 1886. ANNIVERSARY MEETING. Report of Auditors ........ votwtane caddabde Heal CoO RURRpWOs rut crnt'sconsavedes\'veecitt be genera a 372 List of Fellows deceased since last AMMIVersary .........ccccceeccecesceseeceeeceeeceneeene 372 Clected . cvissnrcaradesese cee esderstnsfvacansu+cigsteangseenssee pein nee ae 373 madness of the President)S...2ta... 1380 ,, Seals 78 Sith AS, Mr. Fox does not give the temperature of the air, but states that the abnormally low temperatures of Stations IT and IV arose from the passage of strong currents of air. The effect of these conditions, in estimating the rate of increase of temperature with depth, is clearly shown in the last column which I have added for this purpose. But although there may be extreme cases, it is probable, as a general rule, that the ventilation does not produce the extent of difference between the temperature of the air and of the rock that it does in coal mines. Mr. Fox who, to avoid the effects of ventilation, always, if possible, made his observations near the ends of the levels, states that in those cases there is little difference between the temperature of the air and the rock. At the same time it is possible that, even then, the uniformity may be owing to the rock having permanently cooled down to the temperature of the air—though it may not be much. The following are cases in which the temperatures of both are given. Temperature. Rate ooo of increase Depth. Air. Rock. pen iah: No. 71. Par Consols.... 1248 feet.... 82° 84° 38 feet We. 72. Botallock:...... Sn ae Shiono 40 ,, Meg? evant...) 4. TSE 0) pap peas Aue fis No. 79. Tresavean...... 771 | aie ie a 91°5 90°5 On ts Here it will be observed that there is only a difference of 1° to 2° between the temperature of the air and the rock, and that the rate of increase with depth is, with one exception, much more uniform. May not circumstances such as these account for the marked dis- 28 Rrota, Prestwich. crepancies in the rate of temperature with depth observed in the Talargoch Mine (No. 158, 160) ; for although the temperature of the air is not there given, we know that it will vary with the distance from the shaft, of which particulars are given in the Brit. Assoc. Reports :— Rate of Distance Temp. increase with Station. Depth. from shaft. of rock. depth. Hi. <. ‘660 feet 120 yards S. 54° FB. 132 feet We Poe & 170 ,, SE. 52:9 10" [Ve ess | ACOn ig, LOO" FeistheOoNY 53°A ig vey Tepe OTE 100 A REDE 60:8 88, Wis 1) Goon 840 , SW. 58:8 64°", Vil... 660, 1240 .. SSW. 62]. The two partial exceptions (IV, V) are in both cases at stations of lesser depths, and, being still near the shaft, are possibly more exposed to the influence of the outer air. The effects of ventilation are also shown in another way. Some of the early experiments of Dr. Forbes were made in the water in swmps and pools, which necessarily would be much exposed to the cooling effects of the circulating air. His tables, which give the results of observations in six mines (No. 18), show a rate of increase of tempera- ture relatively less with increased depth. The observations are so much at variance with those subsequently made by Mr. Fox and Mr. Henwood, that I can only attribute the discrepancy to the cause I have here named, viz., a relatively greater cooling of the water, due to increased ventilation at increased depths. It is not necessary to give the whole series: the following instances bring out the fact :— Temperature Rate of increase Depth. of the water. * 2.) per Meat, 500 to 550 feet ares 65° Bieler 35 feet* 900 ,, 950 , co poe i | Se 1350 ,, 1400 ,, Peis Sag his ATL ,, The early observations of Mr. Fox, which were made in the same way in the water in fifty-three mines, gave also a diminished rate of temperature with increase of depth :— Rate of increase Mean depth. per 1° F. Son Teh ava eile ties: 1° in 35°4 feet BABU Lot ce arte alee be letie tats 1, 40° GAS 5 iat ebstome een a Le? .,,) (O40 ee * The rapid rate constantly observed near the surface is probably in great part owing to chemical decomposition in the lodes which is most active near the surface, and also to a less active ventilation. On Underground Temperatures. 29 No further particulars and no greater depths were given, but Mr. Fox’s later observations in rock give different results. The Hffects of the Percolation of Water.—But while the effects of ventilation are not so general and disturbing in Metallic Mines as in Coal Mines, the effects produced by the underground waters are of much greater importance. The alternation of impermeable with per- meable strata, and the multiplicity of faults in the Coal-measures, so impede the descent of the surface-waters, that there are mines so dry as to necessitate the introduction of water to keep down the dust. The Metallic Mines being, on the contrary, commonly in crystal- line, schistose, and slaty rocks, have more uniformity of structure ; and, being also generally hard and compact, they are more or less impervious. When, however, they have been disturbed and fissured, they give freer passage to water; and when, further, they are traversed by veins and faults, these frequently serve as channels or conduits, more or less free, for the surface-waters, and considerable quantities of water pass through them. Consequently water is one of the great obstacles to deep mining with which the workmen have to contend. Water finds its way to all depths, and with more or less rapidity. Mr. Henwood states that in some mines a great increase follows soon on heavy autumnal rains, and that in others, months intervene before the effects are felt. In districts formed of the usual alternations of sedimentary strata, it is estimated that on an average about one-third of the rainfall passes underground; while in Cornwall, where granites and slates exclu- sively prevail, Mr. Henwood estimated in his survey of the Gwennap district—which consists chiefly of slates—that about a fourth of the rainfall is absorbed, the mean annual rainfall there being 46 inches, — or equal to 166,834 cubic feet per acre. The local percolation is, how- ever, extremely variable, as in some mines the quantity pumped up does not exceed 5 gallons, while in others it amounts to 186 gallons per minute. The same observer found that water passes more freely through slate than through granite, the quantity yielded by mines in slate being about four times as much as that in granite. In a period of five years (1833-7) the water pumped per minute from forty mines, amounted on a mean to the following proportions :— Granite. Slate. wei Cian hy ENT gene me Noni 1g Maximum. Minimum. Maximum. Minimum. Opn Rass 16 ee 122 ee 631 cubic feet | per minute. Mr. Henwood’s account of the quantity of water that passes under. 30 Prof. J. Prestwich. ground in the Gwennap district is of much interest. The mines in that district, over an area of 5500 acres, were combined for drainage purposes. A great adit carried away the water above the sea-level, while a deep-seated level collected the water at the depth of from 1100 to 1200 feet. At the time that Mr. Henwood wrote, the former was discharging 1475 cubic feet per minute, and from the latter 909 cubic feet were being pumped up, or together above 10 million gallons in the twenty-four hours. Taking the mean temperature of the surface at 50°, as the water issues at a temperature of from 60° to 68° F., or at an average of more than 12° above the mean of the climate, it is easy to conceive how large must be the amount of heat which the waters abstract from the mines, and how considerable the cooling of the enclosing rocks which must result therefrom. Another observer, writing a few years earlier, states that the dis- charge at the Huel Vor Mine from a depth of 950 feet, was 1,692,660 gallons every twenty-four hours; at Dolcoath Mine, from about 1400 feet, 535,173 gallons; and at Huel Abraham Mine it reached the large quantity of 2,098,320 gallons.* Mr. Henwood remarks that ‘‘the largest streams of water flow through cross-veins ; small ones through the lodes, whilst but little issues from the rocks whether granitic or slaty.” Where the water dribbles slowly through the rocks to great depths, it will no doubt acquire the normal temperature of the depth, but where it passes more rapidly through the veins and lodes, the temperature will depend upon the time occupied in transit and on the volume of water. If the flow is rapid, as it evidently is in some mines, the surface-waters may carry the influence of the above-ground tempera- ture to considerable depths. If on the other hand, the vein is one in which the ore is subject to decomposition by the surface-waters, those waters will have their temperature more or less raised. A copious - stream of warm water is considered among the Cornish miners a favourable indication of the proximity of a lode. Nevertheless, Mr. Henwood, who, as we may feel assured, fully understood all the contingent conditions, considered that by a careful selection of the underground springs and by taking them when freshly opened, they gave safer temperature results than did the undisturbed rock. Hor Sprincs.—These are not uncommon in metallic mines. They are due to two causes. Istly, to chemical decomposition ; 2ndly, to water coming from greater depths. The first of these causes is a very general one—especially in copper and iron mines, in which the lode consists of iron and copper pyvrites. The surface-waters decompose these sulphides, converting them into sulphates, which by further changes that need not be here described, pass into the oxides and carbonates of these metals. That the action * Dy. Forbes, ‘‘ Trans. Roy. Geol. Soc. Cornwall,” vol. ii, p. 167. On Underground Temperatures. 31 is general is shown by the circumstance that the upper part of all these lodes consists near the surface of a crust, several feet and some- times several fathoms thick, composed of the oxidised products of copper and iron sulphides; this part of the vein is known in Cornwall under the distinctive term of gossan. In these cases, the water is commonly impregnated with some of the resulting soluble sulphates, and has its temperature raised by this decomposition. Mr. R. Hunt mentions* two marked instances of the heating effects arising from this cause. In one case the temperature in the level of a copper mine stood at 100° F., but on the removal of a very large deposit of the copper pyrites “the level became cold enough to make the agent wish for a great-coat.” The exact difference is not given. In another case, a large deposit of iron pyrites was opened at about half a mile distant from a hot lode, 1530 feet deep, in the Clifford Amalgamated Mine, and the mere fact of opening the mine there and removing the iron pyrites, considerably reduced the temperature in the mine. When it was closed the temperature rose to its former height. Springs of various degrees of heat (one was as high as 124°) are often met with. The miners of Cornwall have long held that the lodes containing tin are, at equal depths, colder than those in which copper ores occur ; a fact which is no doubt due to the facility with which the cupreous pyrites decomposes. There must also be cases in which water from greater depths is brought up along lines of fissure (lodes and cross-veins) ; for as these are prolonged downwards, they may traverse at greater depths strata, veins, or faults, charged with water, which, when thus tapped, will outflow at any levels lower than the height at which the water stands in the supplying source. It sometimes also happens that at the same depths, but in distant parts of the same level, the water is of different temperatures. In one instance there were springs at 102°, 110°, and 124°, and in another case (Wheal Wreath), the temperature of a small stream at the east end of a lode (tin) was 71°°5, while a spring at the west end of the lode had a temperature of 75° (both being at the depth of 1422 feet). On the other hand, when the water is in considerable volume, and percolates rapidly, it must tend to have a lower temperature than the normal rock temperature, as in the instance where, in two adjacent mines, large streams both coming out of veins, had the same tem- perature of 67°5° at the respective depths of 588 and 722 feet. The observations of Henwood likewise tend to show that the range of temperature of water in the same level is subject to great variation. In consequence of the uncertainty attaching on the one hand to * Coal Commission Report, A 4—10. 32 Prof. J. Prestwich. observations taken in rock, and on the other to those in water, Cornish geologists have been divided in opinion as to the best plan to adopt. The two great authorities on the subject, Mr. R. Were Fox and Mr. W. J. Henwood, respectively gave preference,—the one to rock and the other to water (or rather springs),—and we may feel sure that the subject was well weighed and considered by both. Hither system is in fact open to some objections, and neither can be employed with- out recourse to those safeguards and precautions, which no one knew better how to use than these two experienced observers. Mr. Henwood gives as his reason for preferring springs,—that the rocks forming the sides of the shaft and levels must, to a certain extent, partake of the temperature of the air circulating through them, and that this air could not escape the influence of heat-producing causes at one time, and at another of the cooling effects of the intake- air. For the same reason he objected to the use for temperature pur- poses of the water standing in the levels, or swmps. He found it difficult to select stations at which the influence of those conditions would be always alike, and he was led to confine his observations as much as possible to the temperature of the streams of water imme- diately as they issue from fresh opened unbroken rock,—before they could be affected by the temperature of the levels,—as the places which would give the most correct temperature readings. The following observations appear to me amongst the most reliable of those obtained in springs. The deepest seated springs are probably the most free from interference by the surface temperature and other disturbing causes. No.in Mine. Therm. | Spring in | ) Table. ED al a a gradient. | rock or lode. feet Fahr. feet 2A Mist dives OOnsols) cseye ea 2 3 810 ile 41 Rock. 49f.| Wheal Trenwith ............ 660 66 44, Lode. | 49g.| South Roskear . Sis ores 834 71 40 Lode. | AXa.| Hast Wheal Crofty.. bere aeRO TOUT 39 Rock. 59. | Tresavean . ee Ee reaee aA fee 72 93°5 48°5 Rock. 23. | Dolecoath. DTA Batt sce ol LAA) 82 AD Lode. | 490. Consolinneds ferret ere etal; cad g OAt 92 °5 Al *5 Lode. | 49c.| United Mines. Peele LOSO 74, 45 Lode. | 491. | Hast Wheal Virgin . ca 1722 94.°5 39 Rock. | 52. | Devonshire Wheal Friendship. 810 69-5 41 °5 Lode. Mean. . 42 °4 Instead of a few selected observations, Mr. Henwood took a larger number and a wider range, though to this there is the objection that he thereby includes a number of extreme and doubtful cases. Thus, On Underground T emperatures. 33 he took the large number of 415 observations made in ten Cornish mines, and on reducing them to given mean depths, obtained the following rate of increase of temperature with depth :— Average Mean temp. Rate of increase depth. at depth. per 1° Fahr. 1. 180 feet Neate 548° eee 36 feet Me Ae |, at 60°8 aide AQh ts; ime (O02 ., eas 67°4 Nisa 43°5* ,, Ive toO: .,, are taae 730 Bat. « Ahi He elsewhere gives the mean temperature for other depths :— Mean depth. Mean temp. | Rate of increas 672 feet sas 66°9° rele _ 40 feet 1440 Ae Vie 85'5 Aes 40°5 ,, 99 He noticed also that there was a difference between the tempera. ture of the springs issuing from the granite and those from the slate rocks. The mean of 134 observations made to a depth of 12006 feet in Cornwall and Devon, gave the following thermometric gradients— Imieramite . 64... 41-5 feet per 1° Fahr. asslaterc wll... 39°0 i Further, taking separately the springs issuing from veins of dif- ferent characters, he arrived at the following results :— For cross-veins at a depth of 594 feet .... 40-0 feet per 1° For lodes generally __,, COO eM ee ailG For copper lodes ao SAO Ee een aie e500) Hf For tin lodes . OO Ten Meter erat) cok 7G < The result of these and various other calculations, is that for the springs issuing from the rock, the mean thermometric gradient was 40-1 feet, and from the lodes 40°3 feet per degree. The early observations of Mr. Fox were made in the mine waters, but his later experiments were made in the rocks, and he expressed afterwards some doubts as to the value of his earlier experiments.t He considered that the rock observations were free from the direct influence which the descent of the surface-waters exercises on the lodes * T am unable to explain this difference. The more rapid gradient in No. 1 is probably due to the heat resulting from the oxidation caused by the surface-waters + There would appear to be some mistake in this figure, as in another page he states that the temperature in the tin and copper lodes conjointly at a mean depth of 444 feet is 61'4°, which gives a rate of increase of 39 feet per degree. ft Some were made in still water or swmps ; others in the air of the levels. VOL. XLI. D } fe . 34 Prof. J. Prestwich. and cross-veins—of which the effects may either be to raise the tem- perature of the underground springs when chemical decomposition is going on in the upper part of the lode, or to lower the temperature when the surface-waters are abundant and infiltrate rapidly. The following observations made in the rock appear to be amongst the most reliable of the results obtained, the temperature having been taken in holes 2 to 3 feet deep, and the stations having been selected at places where no working had recently been going on, and as distant as possible from the shaft :— | No. in : Temp Hate Table I, | Name of mine. Rock. Depth. | oe vock of increase | Observer. ; "| for feet. feet. 19 Doleoath ..... Granites. |) 1350 oer 48 Fox. 36a—%3%| Levant.......| Granite and| 1530 87 i x 43 °7 ” slate Mi 85 52 Botallock ..... Granite and| 1128 | 79 40 A greenstone ‘ 80 Fowey Consoli- dated.o. <6 < the! sis cael) SO e2Ga BOs Al a rfl Par Consols... Bey EA terials 1248 | 84 38 i 40 Consolidated..| Slate ......| 1740 | 85°3 49 Henwood. 122a |Tresavean ....| Granite....| 2130 | 99 43°5 | Hint. 48 Tresavean .... ¥, P 1572 82°5 48 °5 Fox. Mean.. 44 feet This gives a mean thermometric gradient of just 44 feet per 1° F., or combining the results obtained by observations in springs with those in rocks, we get an average gradient of 4:3°2 feet per degree. Mean of observations in springs ......... . 42-4 feet ‘ if ROCKS) Jey entice ames -, 440 Mean.. 4372 ,, Foreign Mines.—We know too little of all the conditions which obtain in foreign mines to draw any definite conclusion as to the rate of increase of temperature. Possibly the observations may prove available when we have more certain information respecting the mean annual temperature at each place, the height of the mine above the sea, and the position, especially in mountainous districts, of each station with reference to its depth beneath the surface. This latter element is one, which the coal-mines observations pre- viously given, clearly show should be taken into account. In Cornwall it is not of much importance, as the elevations are small, and the On Underground Temperatures. 35 mines are rarely more than 100 to 300 or 400 feet above the sea level; but the mines of Freiberg are on higher ground, whilst those of Prizbam and Chemnitz are situated amongst high hills, and the tem- perature at the end of a long gallery may be, in relation to depth beneath the surface, very different to that given by the depth of the shaft. The mines of Freiberg are those in which the greatest number of observations have been made, though none of them are of very recent date. The deepest mine, and one in which the observations were made in holes in the rock (gneiss), gives, if we are right in our estimate of the surface temperature,” a rate of increase with depth of o4 feet per degree. But in this instance,—as in the case of Mr. Fox’s observation (No. 73) in Dolcoath Mine, where the thermometer was left In position for one and a half year,—it was here left two years, and there must have been as before described, a cooling of the rock, such as would reduce the temperature so far below the normal, as to place it in equilibrium with the temperature of the cooler air in the galleries. The temperature of 66° at Freiberg, and of 76° at Dolcoath, with their thermometric gradients of 54 and 53 feet, I take to represent the normal temperature of the rock, minus the loss of heat due to ventilation; and if that can be estimated at anything like the loss shown to have taken place in a level in the Wheal Vor Mine, which, after it had been opened some time and the mine had been deepened, amounted to about 6°, or in a similar instance mentioned by Mr. Hen- wood, where the difference amounted to 7°, it would indicate a normal temperature of these mines more in accordance with the gradient which we have adopted on other grounds. For the same reason the numerous observations made by Mr. Hen- wood in the mines of Brazil and Chili, are, for the present, not available, though it is possible that they may be rendered so at a future period, should the other factors necessary for determining the difference between the surface and the underground temperature be ascertained. III. Artesian Wells and Borings. (Table IV, p. 106.) This class of observations presents results much more uniform than those taken either in Coal or Mineral Mines, and whereas the obser- vations in Mines were in Paleozoic or crystalline rocks, those in Wells are, with few exceptions, either in Cretaceous, Jurassic, or Triassic * This is based on the temperature of Dresden, the nearest place where we have . recorded observations. The mean annual temperature of Dresden is 47°, and as the mine is situated at the height of about 1300 feet, or about 900 feet above Dresden, if we allow 1° for every 300 feet of elevation, we shall have about 44° for the surface temperature at the mine. D 2 36 Prof. J. Prestwich. strata, where the rocks are, as a rule, softer, more permeable to water, and less disturbed. Many of the interfering causes difficult to eliminate in the case of the Mines, do not exist with the Artesian Wells. The causes of interfer- ence in the latter are reduced mainly to two, namely, pressure on the instruments and convection currents. The early experiments, where no precautions were taken against pressure, are consequently un- reliable. Walferdin introduced improved and protected instruments, although in some previous cases, as in Marcet and De la Rive’s observations, protected thermometers had been used. The need of protection against convection currents had also not escaped attention, but it was not until the later observations, instituted by the Com- mittee of the British Association, were made, that more efficient safe- guards were introduced to protect more completely against the subtle influence of these currents. It is clear that we must reject all the early experiments made with unprotected thermometers; and it is not certain whether also a large number of those made with protected thermometers, but without pro- tection, and sufficient protection, against convection currents, should not also be rejected. In large bore-holes the disturbance from this cause is so great that the consequences are at once sufficiently apparent to oblige the rejection of the observations. The ordinary deep artesian wells of Paris, such as Grenelle and others, all agree in showing a rate of increase of 55 to 58 feet per degree F.; but the great bore-hole (4¢ feet in diameter) through the same strata in another part of Paris (La Chapelle St. Denis), where the water does not overflow, gave arate of increase of 394 feet per degree for the first 100 métres (328 feet), which is too rapid, whilst at the depth of 660 métres (2165 feet) the rate of increase was only 1° in 84 feet. This is clearly due, as stated by Professor Everett, to the over- heating of the upper part of the column of water and to the cooling of the lower part by the action of convection currents. In the report of a deep boring at Moscow it is stated, but without explanation, that from 350 feet to the bottom at 994 feet the temperature was nearly constant at 10°1° C. (50°2° F.). The diameter of the bore-hole is not given, but I judge from other circumstances that it is not less than 2, feet, and can only account for the uniformity of temperature by the action of convection currents. The mean annual temperature of Moscow is 39°4°. Professor Everett* also directs attention to the manifest action of convection currents in a shaft at Allendale, about 350 feet deep, with nearly 150 feet of water, in which the temperature was practically the same at all depths. * Brit, Assoc. Reports for 1871 and 1869. On Underground Temperatures. 37 Depth. Temp. 160 feet. aheeatte 475° 2005) 53 ae A7 DO! ge 5 als A7-7 B00) 5; Sas ad, One of the pits at Allenheads (No. 130) which was nearly full of water gave similar results. Depth. Temp. 50 feet. Netaes 472° OO; ye Aas 46°8 OO me Re ae 46°6 SOU) ali 46°9 While in another shaft at Ashburton 620 feet deep, and with water standing to within 50 feet from the surface, the temperature at all depths was 53°, except at one point, where it rose to 53°4° and 53:2°. Hven in the deep and narrow bore-hole at Sperenberg, it was shown that the first experiments with thermometers protected against pressure, but not against convection currents, gave wrong results, for in the first instance at a depth of 100 feet, the temperature was found to be 11° R., and at 3390 feet, 341° R. Afterwards, when plugs were inserted to stop the currents, the temperatures at the same respective depths had altered to 9° R. and 36:16° R., showing therefore that the first readings were too high by 2° Reaumur near _ the top of the bore, and too low by 2°05° Reaumur at the bottom. _ Another experiment in the same well later showed that the difference at the bottom, between plugging and no plugging, was as much as oO, Hahr.* Another narrow bore-hole, showing clearly the action of convec- tion currents, was that sunk to a depth of 2000 feet, at Swinderby, Lincoln (No. 143).+ The Eole had remained undisturbed for nearly three weeks, and the water stood within a few feet of the top. Depth. : Temp. 100 feet. mee GSiokr. B00 Rai: Eee 68°75 500 ,, otal 68°70 GOO fs poder’ 69 G00 ai) Tok 69 NZ00 se qaere 69°5 2000 ,, Les, 79 Taking the mean annual temperature of Swinderby at 48°, this * Brit. Assoc. Report for 1876, p. 205, and 1882, p. 3. The differences were even considered to be under-estimated. {~ Brit. Assoc. Reports for 1875 and 1876. Part only of these are in Table I. 38 Prof. J. Prestwich. gives a difference of 31° for the whole depth, or 644 feet increase for each degree F. If it stood by itself this might appear nothing remarkable, yet it is evident, from the series of observations that were taken in this bore-hole, that the temperature or rate of increase at the depth of 100 feet, which was equal to 1° in 10 feet, and at 300 feet to 1° in 28 feet, is excessive, and that this excess can only have been acquired through loss of heat by convection currents at the bottom and a corresponding gain at the top, and thus making the readings too high at top and too low at bottom. If, however, we take an intermediate station at a depth of 1000 feet, where the temperature averages 69°2°, we get a mean, and more probably truer, rate of increase with depth of 47 feet per degree. Owing to the large diameter of the bore, to the many water-levels in the rocks, and to the circumstance that when the observations were made there was no sufficiently free outflow of water on the surface, such as would check the convection currents, there can, I think, be no doubt that the temperature of the well at Bootle (No. 163), sunk in the New Red Sandstone at Liverpool, is influenced both by convection currents and by the influx of waters at different levels. It is clear, therefore, that great uncertainty attaches to all observa- tions made in bore-holes with standing water, the error being in proportion to the diameter of the bore-hole; and that where experi- ments have been made without plugging, all the deep temperature readings will be too low. Hven with this precaution, it may be a question whether the bottom water and that of the adjacent rock may not have had their temperature permanently lowered before trial. This might be remedied to some extent by the use of more than one plug, and the stoppage of the circulation throughout the whole depth of the bore-hole for a certain time. There are, however, some artesian bore-holes, where the sources of error have been reduced to a minimum. Amongst those are— 1. Kentish Town (No. 129).—These careful experiments were carried on for some years by Mr. Symons. From the circumstance that the mud at the bottom of the bore-hole into which the thermometer was sunk, was free from convection currents, the results obtained show, in all probability, a near approximation to the normal temperature. At the same time the long period that the well had stood neglected allowed the play of those currents in the water standing in the tube above the mud, and this may possibly have effected a slight reduction of temperature, but it cannot be very material. 2. Richmond.—The observations here were made by Professor Judd. with standard instruments. The overflow was too small to give the correct temperature, though enough to check convection currents, — and consequently the temperature was ascertained by letting down a thermometer to the bottom of the well. On Underground Temperatures. 39 3. The first experiments at Grrenelle were made when the bore-hole had reached the depth of 400 métres (1312 feet), and when no work had been going on for some weeks. The thermometers, of which three sets were used, were left down thirty-six hours. They were protected against pressure, and Arago remarks that the chalk through which they were boring made so thick a paste filling the bore-hole, that convection currents were hardly possible. All three sets of instru-. ments gave results within a fraction of a degree to one another.* 4, In the bore-hole of the well at the Ecole Militaire the experi- ments were made by Walferdin under very similar conditions. 5. Pregny near Geneva.—The thermometer was here protected against pressure, and toa certain extent against convection currents. The bore-hole was small, and the water stood at a small depth below the surface. 6. The observations at the well at Ostend, with the water also slightly overflowing, were made by Professor G. Dewalque, of Liege, with protected thermometers at the bottom of the bore-hole. 7. At Sperenberg, especial care was taken against convection cur- rents, though how far these currents may have operated in reducing generally the temperature in the lower part of the bore-hole, before the experiments commenced, may be a little uncertain. These seven wells give a mean rate of increase of rather more than 51 feet for each degree F. in depth (see p. 40). The reason why I have not included a larger number, is because in these cases I believe in the existence of some undetected errors, such, for example, as, amongst many others, those mentioned in the following instances. Swinderby.—I have already explained my objections in this case. Of the first series of observations down to a depth of 1500 feet, Pro- fessor Hverett remarks “it is obvious that nearly all the tempera- tures are largely affected by convection,” he considered the bottom temperature at 2000 feet as less likely to be vitiated by convection in consequence of the small diameter of the bore-hole. [But if we take, as I have suggested, a mean depth and a mean temperature, I believe we should have in the thermometric gradient of 47 feet per degree, a nearer approach to the true normal at Swinderby. Hiven in cases where the temperature is uniform from top to bottom, and there appears to be no clue to follow, as in the instance with the Moscow Well (No. 135), where Professor Lubinoff records a tempera- ture of 10°1° C. (50°2° F.), if not for the whole depth of 994 feet, at least from 350 to 994 feet, it seems possible to obtain an approximate gradient. F'or the mean annual surface temperature being 39°5° F., and the half depth 494 feet, if we divide this by 10°7° (the difference * T have adopted this observation for Grenelle, in preference to that on the over- flow water, for the reasons given further on. 40 Prof. J. Prestwich. between the surface and the well temperature), we get a quotient of 46°5, which agrees nearly with the thermometric gradient of the well at St. Petersburg (No. 44). March, 1886. | Southampton.—The well was too long disused; during that time convection currents operated; apparently no protection against con- vection currents during the experiment. Bootle.-—The influx of water at different levels, and convection currents, render the results here valueless. fiouen, St. Sever.—The thermometer was not protected against pressure, but-the effect of the pressure was estimated and allowed for. Troyes.—M. Walferdin thought it probable that the observations were affected by the heat caused by the boring tools, sufficient time not having been allowed to elapse after working before the thermo- meter was sent down. Artesian Wells and Bore-holes in which the Water stood below the Surface, or rose very slowly so as to render it necessary to take the temperature at the bottom of the bore-hole. Temperature. aux a aera ie Place. Strata. Depth. metric a0" Mean | gradient. Og Bouse surface. feet. | Fahr. Fahr. feet. | | | 129 Kentish Town | Tertiary, Chalk, and Old Red Sandstone | 1100 | 69:9° | 49° 52°3 ‘231| Richmond....| Tertiary, Chalk, Ju- PASSIC, OCC» reeuns «eT |i OES 49-6 515 37 | Grenelle, Paris| Tertiary, Chalk, and Greensand........ 1312 | 74:7 5l 55 36 Ecole Militaire,| Tertiary and Chalk..| 568 | 61°5 51 54 Paris 29} Pregny ......| Tertiary (Molasse)..| 713 | 62°7 47 48 °5 203) Ostend ......| Tertiaryand Chalk..| 981 | 71°6 50 45 144 | Sperenberg...| Triassic rock salt and} E. ft. Gypsum ........| 3490 | 115°5 48°38 52 Mean 651°2 Overflowing Artesian Wells—We now come to surer ground. Under certain conditions, these wells must give not only the nearest, but a very near, measure of the underground temperature, at the level from which the water rises. These conditions are— lst. A sufficient depth and a sufficient distance of the out-crop of the water-bearing strata from the point of overflow. In a case like the Grenelle well, which is nearly 2000 feet deep, and where the stratum which serves as a channel for the water does not come to the On Underground Temperatures. 41 surface for a distance of above 100 miles, these conditions are most favourable. It is very interesting to find, from information which M. Daubrée has just (Dec., 1884) obligingly obtained for me, that the temperature of the water at the Grenelle well is now precisely the same (27°8° C.), if not 0°1° C. higher, than it was at the commence- ment of the overflow forty-two years ago. In London, the distance of 10 miles at which the Lower Tertiaries and the Chalk out-crop is also no doubt sufficient, but itis a question whether the excessive pumping and constant passage of water may not have cooled the channels. 2nd. A sufficient volume and consequently rapid upward flow of the water in proportion to the depth, otherwise the water will part with some of its heat, as it rises through the tube. This may possibly be in some small degree the case at Grenelle, for in the carefully con- ducted observations of Arago and Walferdin, when the well had reached a depth of 400 métres, the temperature (23'75° C.) gave a rate of increase of 55 feet per degree, instead of that of 58 feet when it overflowed. At the Ecole Militaire, the rate was, as ascertained by Walferdin, 54 feet. It is possible, therefore, that the slower rate of increase at Grenelle indicated by the overflow water at a greater depth (548 métres) may arise from a reduction of temperature due in part from the water overflowing with a velocity by no means great, but mainly from the diameter of the tube at the top being considerably greater than at the bottom. The conditions of depth and volume are generally satisfactory in the case of the great saline wells in Germany, especially in the instance of the well at Neu Salzwerk. Humboldt states the supply of water was very abundant, the outflow being then at the rate of 422,000 gallons daily. Its ascensional force was remarkable, as was also the enormous discharge of carbonic acid. The deep artesian wells of Minden, which derive their water from the same source, give very similar results. The discharge of water at the thermal springs of Mondorff in Luxembourg is very much less than at those of Neu Salzwerk. It is situated further south, and the height of the ground is consider- ably greater, being 673 feet above the sea-level; the mean annual surface temperature adopted by Walferdin was 48°4° F., but this was only an estimate. The mean temperature of Luxembourg, according to Arago, is only 8° C. (46°5° F.). The depth of the artesian well at Tours is much less than that of the above, but the ascent of water was rapid and the discharge large. The observations there were made by Walferdin, as were also those at Rochefort. The following list is confined to those wells where the overflow is abundant, and where the observations have been made by competent observers. 49 roe ereetavieht Artesian Wells in which there is an abundant overflow of Water at the Surface. Temperature. Rate = a of = 8 Piace. Strata. Depth. _ | derease Sis Mean er 5 = At depth. surface, | 1° Fahr. feet. Fahr. Fahr. feet. 4% Paris, St. Quen) Tertiary.......-..|- 216 | 5a°3- 51° 50 32 | Lille.........) Cretaceous ; Carbo- niferous limestone] 329 | 57°2 50°5 49 2 Vours,...5). woe |Oretaceous sca. |, 460 63 °5 ra}o) 44, 101 | Rochefort..... UD Gen sie ies i a eRe am ore 2812 | 111 54°5 50 63 | Mondorff..... Lias and Trias ...| 1647 | 78:3 47 °3 53 182 | Minden ......| Triassic (?).......| 2230 | 90-9 48 52 34 | Neu Salzwerk.| Liassic and Triassic | 2038 88°3 48 50°5 144q| St. Petersburg.| Silurian.......... 656 | 54 he) a7, 44. Mean.. 49:1 We thus have in these wells an average rate of increase of 49 feet for each degree F., or if we take the mean of the two lists, of almost exactly 50 feet per degree. Before, however, accepting this conclusion, two points should be reserved for correction hereafter, namely: Ist, the determination of the precise temperature at a depth where the annual surface changes cease to be felt. 2nd, whether there is any loss of heat, and what the amount, by the water in ascending through the tubes. This latter is, I believe, not an unim- portant consideration. The experiments at Grenelle indicate the probability of some such loss, and the form of construction of the tubes gives strength to the supposition. If the tubes of an artesian well were of the same diameter throughout, the passage of any given portion of the water from the depth to the surface would be direct, and the velocity the same throughout ; but the tubes in almost all these wells decrease in diameter from the top to the bottom, consequently, instead of the whole body of water being in continuous and uniform motion throughout the length of the tube, the velocity of the water gradually decreases from the bottom to the top, currents are established at the points where the tubes enlarge, and a certain time beyond that required for its direct trajectory must - elapse before the whole of the water issues at the surface. For example, at Grenelle, where the difference between the size of the tubes at the top and bottom of the bore-hole is less than in some wells, there are four tubes of the respective diameters of 0°25 m., 0°22 m., 0°18 m.,and 0°17 m. As the lesser the depth of the well tie On Underground Temperatures. 43 fewer the changes of tubes, the differences in this respect, together with the differences in length of the tube, may possibly help to explain the reason why the wells of 300 to 600 feet deep gave gene- rally a more rapid rate of increase than the wells of 2000 feet, and may also account for the different rates of increase at the several wells, for which otherwise there is no apparent cause. I have excluded a large number of overflowing wells because of the uncertainty which attaches to the instruments used, or to some essential point of which we are in ignorance, such, for example, as the influx of other springs, the precise depth, the size of the tubes, &c. These reasons apply to such wells as those of Newport (No. 210), Falkirk and Midlothian (45), Dunkirk and Bourbourg (209, 208), Alfort (49), Meaux (62), Arcachon (183), and others, where we do not know whether or not standard and protected instru- ments were used, or whether the experiments were in all such cases made by competent observers. With respect to the extra-Huropean observations, still greater un- certainty attaches from our ignorance of the general conditions, and especially of the exact mean annual temperature of the several places. At the same time there are some exceptions worthy of consideration. The experiments in the Sahara Desert (No. 88a) were made by an engineer of great experience in the construction of artesian wells, and accustomed to observations of this description, and are the mean of results obtained at a number of wells. The observations at Charleston and St. Louis appear reliable, only in these cases more particulars are desirable. The African and Indian experiments seem to indicate a more rapid rate of increase of temperature with depth than occurs in EKurope. Not so the American (U.S.) observations, which appear to indicate con- ditions very similar to those which obtain here. Not much weight can be attached to the solitary observation in South America. It requires confirmation. IV. Tunnels. The few observations of this class, limited as they are, show not only the modifications of the gradients caused by inequalities of surface, but bear also on some important geological questions con- nected with the structure of mountain chains and metamorphism. The first great tunnel was that of Mont Cenis, which is about 7 miles long, and passes under a ridge of the Alps rising 9532 feet above the sea level, and 5280 feet: above the tunnel. After making a correction for the convexity of the surface, Professor Everett estimates the rate of increase of temperature with depth to be 1° F. in 79 feet. But the observations there were commenced late, and were not very complete. 44 Prof. J. Prestwich In the St. Gothard tunnel, where very full and complete observa- tions were carried out by Dr. Stapff, the results are of much interest. The tunnel is about 9 miles long; the summit level of the ridge above the tunnel is 10,040 feet above the sea level, and 5578 feet above the tunnel. This, after allowing for the convexity of the surface, gave a rate of increase of 1° F. in 82 feet. But Dr. Stapff* has since pointed out that in one part of the tunnel the rate is considerably more rapid. He found that the relative tempera- ture of the ground above the northern end of the tunnel was much higher than in other parts—that in the plain of Andermatt the mean rock temperature was several degrees above the normal, while at the south end of the tunnel it was some degrees below it. The latter circumstance was easily explained by the presence of cold springs; and some higher temperatures in other parts of the tunnel were attributable to the decomposition of the rock; but there were no apparent reasons for this excess of temperature in the northern end of the tunnel, where it passes through gneiss and granite. The difference was such that instead of a rate of increase of 1° in 85 feet in the centre of the tunnel, or of an average rate of increase for the whole tunnel estimated by him at 57:8 feet, the rate was here 1° F. in 38 feet. Dr. Stapff says that there is no obvious explanation of the rapid increase in the granite rocks at this end of the tunnel, and that it is probably to be attributed to the influence of different thermal qualities of the rock. He mentions, further, that this granite be- longs to the massif of the Finsteraarhorn, which is of a different (newer) geological age to that of the central axis of St. Gothard, and that it is therefore not to be wondered at “if one of them be cooler than the other.” He elsewhere remarks that there is also a well- known local focus of heat (decomposition of rock) below the valley of Andermatt, which may exercise a sufficient influence. I myself am disposed to attribute the greater heat of these rocks to mechanical action rather than to the later protrusion of the Plutonic rocks, or to any subsequent decomposition of these rocks. If the pressure, force, and friction accompanying elevation of mountain chains be attended by the development of great heat—a heat sufficient to produce great chemical changes even in the Tertiary strata—then it may be possible for some of the newer mountain chains still to retain a portion of that heat. The facts brought forward by Dr. Stapff in the St. Gothard tunnel give material support to this view. Although Mallet failed to show that the heat produced in the crush- ing of rocks by the lateral pressure, arising from the contraction of the crust of the earth as a consequeuce of its slow secular refrigeration, * “Trans. North of England Inst. Min. and Mechan. Engineers,” vol. xxxiii (1883), p. 19. On Underground Temperatures. | 45 was sufficient to fuse the rocks and account for volcanic phenomena, he nevertheless brought prominently forward the enormous _ heat- producing power of the disturbances caused by this contraction. He made a series of elaborate experiments to ascertain the force re- quired to crush blocks of a given size (3 or 3} cubic metres), and measured the work done by the estimated heat evolved by the crush- ing of 1 cubic foot of several classes of rock by the number of cubic feet of water at 32° F. converted into steam of one atmosphere, or 212° F. This method, although not perfectly satisfactory, is sufficient to prove the essential fact that a mechanical disturbance of the rocks may develop a large amount of heat. I must refer to his valuable paper* for full details of his results. The following is an abstract from his large table of experiments. ee sn Tempera- | Number of Specific | Weight. | at which| ture of 1 | pounds of Ee. (pressure) cubic foot | water at Class of rock gravity. | per squar ee of rock | 32° ass of rock. Water | Per square! one , evapo- —1000. inch at first Rate due to | rated into yielding. ae work of | steam at nantes! crushing. 212°. lbs. lbs. Fahr.+ lbs. Caen Oolite ........... 2 °337 1,620 4,966 Sy 0-288 Magnesian Limestone ..| 2°571 3,699 16,333 26 0-9 Coal-measure Sandstone.| 2°478 10,970 29,783 86 2°5 Devonshire Marble..... 2°717 11,708 34,938 114 3°44 Bangor Slate .......... 2°859 15,510 41,590 144 4°51 Rowley Ragstore....... 2-827 24,039 | 63,737 213 6°86 Aberdeen grey Granite..| 2°678 16,868 51,123 155 4°44 Inverary Porphyry .....| 2°594 26,149 69,786 198 5°22 Thus with the ordinary sedimentary rocks the crushing weight (or that at which the blocks yield to pressure) is from 24 to 154 tons per square inch of surface, while for the crystalline rocks it rises to 31 tons. The heat produced on the metal surroundings by the crushing was in most cases easily perceptible to the hand, and was so great in some of the granites and porphyries as to necessitate a delay for the apparatus to cool. Both Mallet and Rankin were of opinion that “in the crushing of a rigid material such as rock, almost the entire me- chanical work (with the small residue of external work) reappears as heat.” If, therefore, the disturbance affecting the massive strata of a great mountain range were sudden or of short duration, an intense degree of heat might be rapidly developed; but there is reason to suppose that such movements have been of extreme slowness during * < Phil. Trans.,” vol. 163 (1873), p. 147. + Omitting fractions of a degree. 46 Prof. J. Prestwich. long periods of time, and it was only when the tension had reached a certain point that fracture and disruption, accompanied by a more rapid motion of the parts, took place. What the force of the pressure may have been in these cases is shown by the compression of the strata in the Alps, by the extra- ordinary folds and inversions of the rocks, and by the vertical cleavage (a resultant of pressure) which the whole mass of rocks has undergone. We may illustrate this point by the following generalised section across the central axis of the Alps along the line of tunnel. Fra. 5.—Section across St. Gothard (reduced from the large section of Dr. Stapff). - Massif of the s : Massy of the 3 SC Oothard ee Bastn of Finsteraarhorn / / the Ticino N : 1 x : N S rape os MN OdOLe rae ie F North. ee erate 004 vA South ejeck, ; Forel ‘ \ \ \ Speaks \ Coe ae ey cIICE PEO a Nal Rail gr. Granite. gn. Gneiss. m. Metamorphic schists. ¢. Temperature curves. But although the compression may have been excessive, and the actual mechanical displacement great, the crushing was not so complete nor so sudden as to produce the extreme effects indicated by the expe- riments. Complete crushing is not, however, necessary for our object, since the experiments show that on the first yielding of the rocks, which takes place when the weight is rather more than one-third of the crushing weight, a large portion of heat is given off. Consequently not only would the heat be developed very gradually (and much of it might be dissipated during the long periods that the disturbances lasted), but also the major effects obtained artificially would never be realised in nature. Nevertheless, although fusion may not have taken place, there were molecular and chemical changes produced in the rocks which indicate the existence of very considerable heat ; and there is reason to believe that this heat was often due to mechanical causes, and not to the protrusion of the molten granitic centres. In fact M. A. Favre and other Swiss geologists now consider the granite in those ranges to have been in existence in its present relative place when the elevation and crushing occurred. Mallet further showed that the quantity of heat developed varied greatly in different rocks, and that, although compressed by the same force before their elastic limits were passed, yet, when released, it would render a quartz rock nearly three times as hot as a slate rock. : »; “ y ee ee eee ee eee ee ee On Underground Temperatures. 47 Consequently granite and gneiss, with their large proportion of free quartz, would be more affected than the other rocks. When, therefore, we consider at how late a geological period some of the great mountain chains have been uplifted, it is not impossible, looking at the magnitude of the massifs, that some residual portion of the heat produced by compression, faulting, and crushing, may still exist in such modern chains as the Alps and the Himalayas, or in Continental areas of recent elevation when that elevation has been accompanied by compression and faulting. This is a consideration which, although exceptional, should not be overlooked in the general question of underground temperatures, especially in mining districts, where we have to deal with disturbed areas, with their faults, dykes, and Mineral veins; at the same time, there can be little doubt that the disturbances in most of these areas are of such high antiquity that there is in most instances small probability of the rock showing remaining traces of thermal effects due to these causes. Neverthe- less, when the area has been affected by late disturbances, it is possible for the thermic normal to be influenced by such a cause independently of the action of any volcanic or igneous rocks.* ConDUCTIVITY OF THE Rocks. EFFECTS OF SATURATION AND IMBIBITION. Although it is evidently possible to account for many of the appa- rent discrepancies in the thermometric gradients by the causes dis- cussed in the foregoing pages, yet it is equally evident that there are irregularities —not only between the rocks in the three groups of observations, but also common to individual instances in each separate group—which these causes do not adequately explain. As the rocks in each group are of very different Jithological characters, and as . there are also occasional lesser differences of characters in the members of each separate group, the common disturbing cause may in some measure depend upon those differences of structure and composition which variably affect the conductivity of the rocks. The researches which bear most directly on this inquiry are those of Professors Herschel and Lebourf in this country, and M. Jannettazt in France, the former relating more especially to the differences de- pendent upon the lithological structure of the rocks, and the latter to those dependent on the component minerals. Tabulating the results of Professor Herschel and Lebour’s experiments in accordance with their. geological relations, as grouped in Tables II, ITI, and IV, we obtain the following mean conductivities for the several groups of rocks :— * For a further discussion of this subject see a short paper by the author on ** Regional Metamorphism,” in “ Proc. Roy. Soz.,” vol. xl (1885), p. 425. + The results of their investigation are recorded in the reports of the British Association for 1874-1882. ft “ Bull. Soc. Géol. de France,” 3rd Ser., vol. ii, e¢ seq. 48 Prof. J. Prestwich. Table of Thermal Conductivities of Rocks, compiled from the Tables of Professors Herschel and Lebour. Absolute | Absolute Average. thermal con-; thermal Nature of rock. ductivity, | resistance, k di k. t, (| Granite (mean of five]; 0:°00584 172 varieties). ; 4 Crystalline Porphyry (Germany)..| 0°00513 ss} OUR Les and Volcanic | Porphyritic trachyte ..| 0°90590 169 rocks. | Basalt (Loch ane .| 0:00560 179 Trap (Calton Hill) . 0 -00352 zi} 0°00475 | 221 || Serpentine 000515 199 (| Gneiss (Germany ee 000514 195 Schistose || Mica schist (Scotland) 0 -00520 122 0°00531 | 190 rocksand 4 | Slates (three varieties)..| 0°00561 184: Slates. | » (across cleavage). 0 °00395 263 | Clay-slate (two varieties)| 0°00327 307 Quartzitel ile. . cose cien (RO 200954: 105 (| Ganister sandstone . 000630 159 Craigleith _,, ...| 000947 105 ales | Hard sandstones ...... 0 -00672 = INS fe Micaceous flagstone | 0*00690 145 | (along cleavage). Micaceous flagstone | 0°00492 2038 across cleavage). Sandstones. Soft red ae a aut 0°00397 |. a Uae BEE New red sandstone....| 0°00250 ed | 3 3 wet. | 0:00600 166 Firestone (Upper Green-| 000240 427 sand). 0°00172 | 689 Moe ee sand.. 0:00105 952 | Wee. 0 -00820 122 cbse marble ......} 0°00530 189 Devonian yey ts wiser 0 :00645 UES : eat Carboniferous limestone| 0 °*00550 182 pe Obseak | ae Oaks Nees Magnesian 0 00522 192 olites, &¢. | | Oolite (Ancaster)... 0-00370 | 270 Lias Cn stone) « 0 -00366 278 L| Chalk . 0 -00220 455 Coal-measure ighale 0 -00235 425 L Argillaceous } | Clay (sun-dried) . 0 00250 398 UU S strata. », (the same wet and| 000350 270 soft). White quartz ........| 0°00957 104: Mineral f Alabaster .....2+..+...| 0°00360 278 + | Rock salt . 001280 78 tr ts) || Coal (Newoastle) . 0-G0068 | 1470 \ Camneliconl einen ay nOnOOL20.% 787 Or dividing this series into groups corresponding with the nature of the rocks in the several Tables of underground temperatures, the results are as under :— On Underground Temperatures. 49. Mean Mean conductivity. resistance. k. Ts 1. Coat Mines (carboniferous strata). SAMOSEOMES). otis css ece cess ee 7 mules Clave). is. ss... suas (ial Ee eat 2. Minera Mines (metamorphic and crystalline rocks). Wrystalline rocks ....-......- Schistose rocks; Clay-slates. . . \ > UNITS sou WEB 3. ARTESIAN WELLS (mesozoic and ter- tiary strata). Soft, and New Red, sandstones ; i abeataeescet ae 0-00308 .... 331 Chalk; Greensands.......... i SR Clays; Marlstones (Lias) .... This shows a considerable difference between the conductivity of the metamorphic and paleozoic rocks of the Mineral and Coal Mines, and that of the newer strata in which the Artesian Wells are usually situated; but there are conditions, hydro-geological and structural, obtaining in the rock masses themselves, which introduce many modi- fications affecting the value of these differences. For example, in each group there are subordinate beds, which may have more or less local influence. In the first there are seams of coal, of which the conductivity is extremely small, though these seams form but a fraction of the entire mass. Thus there are— Total No. of Total thickness workable thickness of coal- seams. of coal. measures. In the coalfield of Newcastle .... 16 Bho At LOM 5, se 3,000 ft. e is N. Staffordshire 30 Pose Oneal ri, eo OOO “3 ms South Wales... 75 Batch oe LOG ceo, sll (0) Olas The coal therefore only enters as a very small fractional part into the constitution of the Coal-measures. Besides, the coal seams vary very much in thickness, and are of limited range, that is to say, they form thin plates never coextensive with the Coal-measures them- selves; at the same time, when one thins out, it may be replaced by another on a different level. In the crystalline and schistose rocks, veins and layers of quartz and of quartzite are of common occurrence, though very irregular in their mode of distribution. ° The quartz veins and seams are generally thin, but the quartzite often forms masses of large dimensions. In the Artesian Wells gypsum and rock salt are of not unfrequent occurrence in the Triassic strata; in the remarkable instance of the VOL. XLI, E 50 Prof. J. Prestwich. Sperenberg bore-hole, the latter forms a mass several thousand feet thick.* ) The Influence of Water—The above, however, are but local and minor conditions, subordinate to one of a much greater and wider influence. The conductivity experiments of Messrs. Herschel and Lebour were, with few exceptions, made with blocks of dried rock. In a few instances they repeated the experiment with wet blocks of the same material, and with a remarkable difference in the result. Thus— Conductivity. poe [aa na = Dry. Wet. New Red Sandstone .... 0°00250 ...... 0-°00600 Quartzose'sand Yess 4.) 0 <00105 ous eras 0 -00820 Olay ssekieieie eh area ce 000250. %, ame 0 :00350 Meane sock. 0500202) teers 0 00590 Here we have substances which when dry present great thermal resistance, becoming when wet amongst the best of the rock conduc- tors of heat—equal, if not superior, to that of the crystalline and schistose rocks. This condition becomes, in considering the question of conductivity in relation to underground temperatures, a matter of very great importance, for in nature dry rocks are the exception and wet rocks the rule.. The level of permanent saturation of the strata is regulated by the sea level on the outside, and by the level of the river valleys and their tributaries inland. All the rocks below those levels are, as a rule, per- manently saturated with water, while between the valleys the line of water level rises in proportion to the distance the water has to travel, and the friction offered by the rocks before it escapes as springs. In the chalk hills of Kent or Surrey, for example, which rise to the height of 500 to 600 feet, the water level stands 200 to 300 feet beneath the surface, while below that level, the rock, whatever its thickness, is in a state of saturation. In the valleys the chalk is saturated to the surface ; and Artesian Wells are always in relatively low levels. It is the same with the sandstones of the Trias or of the Coal-measures, only that in the latter the presence of faults often cuts off the supply, and segments exist with but little water except that of imbibition. This water of imbibition, or quarry water, is present in rocks above the line of permanent saturation, it being a property that depends on the capillarity of the rock, which is very strong in chalk and oolite, while it is slight in quartzose grits and sands. There are therefore few rocks in which the influence of water is not felt. * Tt may, however, be a question whether it is not intercalated with thin seams of gypsum. 4 On Underground Temperatures. ol The following is the proportion of water held in rocks by complete saturation :—* Complete ; saturation. Granite (hornblendic) ...... 0:06 in 100 parts. Be ne rae, «.....¢ 4.21. 0:12 Me Basalt, Auvergne .......... 0°33 i Silurian slates, Angers...... 0-19 Devonian limestone ........ 0:08 ' Woalbehales sj. 35 swiss lors ees 2°85 fs Coal-measures sandstone .... 14°30 M New Red Sandstone........ 13°43 i. Imrerivor Oolite: ...5 26 +. « . 23:98 - Calcareous freestone, Paris.. 16°25 Be tacts, tery eee alc eckens 2410 es In the hard granites, sandstones, and limestones, the water of im- _ _ bibition differs but little in proportion from that of saturation. The difference is considerable in the softer rocks. The following are some of the few experiments that have been made on this point. Quarry ' water } Gneiss, slightly decomposed ........ 3°00 F lasbie clay it. 208 i. oh A 19°56 4 Wrullkmetya the Jedi N aie a lls ot 19°30 4 It is clear then that the conductivity of the underground rocks ' must, except in some very hilly districts, be taken solely as that of wet _ rocks. In the harder and more compact rocks there will be little _ difference, but in the softer and more porous rocks the difference arising from this cause must be very considerable. y The conductivity even of coal will be increased, although the _ quantity of water that coal imbibes is very small. But unwrought coal also contains a large proportion of gas—and gas in a state of extreme condensation, or possibly in a state near liquidity, and this also may have an effect upon its conductivity. 4 Foliation and Cleavage.—The other condition, to which we have _ already alluded, is that produced by foliation and cleavage, and by the angle at which the strata lie. Messrs. Herschel and Lebour showed, for example, that the conductivity of slates varies accordingly as it is taken across or along the planes of cleavage—that while the conductivity along the planes of cleavage is equal to that of the crystalline rocks, it is no greater than that of soft sandstones across * These are on the authority of the late M. Delesse, “Bull. Soc. Géol. de France,” 2nd Ser., vol. xix, p. 64. ng 52 Prof. J. Prestwich. those planes. The lamination in micaceous sandstones produces a similar result :— Conductivity. Resistance. ~ Slates, along the planes of cleavage... 0°00561 184 » across i a .. 0700395 253 Micaceous flagstone, along the laminz 0°00690 145 otha 3 0) Beross \,) a MO NOMEIE 203 M. Jannettaz* has extended the inquiry to a great number of other rocks, and he shows that the variation in conductivity in many rocks is largely dependent upon the presence of mica. He found that in a crystal of mica, heat was conducted about two and a-half times more rapidly along the planes of cleavage than perpendicular to it. In augite these axes of the thermic curve are in the proportion of about two to one. Fic. 6.—Mica. Fic. 7.—Augite (var. diopside). a, 6, c, d, the thermic curve; a, 6, the major axis; c, d, the minor axis. M. Jannettaz obtained results of a similar character, varying according to certain physical conditions, in a number of other minerals and in many rocks. The ratio of the minor to the major axis in the following rocks he found to be as follows :— Gueiss ob St, GObiardvi ye 2. «gsc 0. eure Lalo oy) AEOM Meare Mo aIMOM Mi. «tau © «oe oe Lez >» passing imto mica sehist.......,.425ee Le e6s Schists (triassic), St. (Gervais 2. .....).. eee 12a »,., (Carboniterous),,Col Voza /.... .¢ pene 1 : 1:80 Argillacecous schists fied. th oct o A0 cee 1 2 tZo Cambrian Slate, Deville (Belgium) ........ T2186 Fissile micaceous limestone ................ 1: lol Black and white limestone, Bonneville ...... 1: 1:06 * “ Bull. Soc. Géol. de France,” 3rd Ser., vol. ii, p. 265; vol. iii, p. 499, e¢ seq. On Underground Temperatures. 53 The thermic curves attain their maximum variation in talcose and micaceous schists and in slates. The greatest inequality, 1 : 3, was shown by a specimen of a talcose rock, of sp. gr. 2°7. The variation exists in all rocks showing schistosity or lamination, but in ordinary stratified rocks the thermic curve remains that of the circle. It was found that the variation exists also in rock crystal, gypsum, felspar, &c. All the specimens experimented upon were dry. It is evident then that in gneissic rocks and slates, the dip, cleavage, and foliation may have a very important effect on the conduction of heat; lamination has a similar but lesser effect in argillaceous shales ; in ordinary sandstones aud limestones no such effects are produced. Whilst these effects therefore may be very manifest in the rocks generally associated with Mineral Veins, they can only be small in Coal Mines, although they may be in some places increased by a larger proportion of mica in the sandstones and shales. There is also the further consideration with strata, such as those of the Coal-measures, that although there may be separately little difference in the thermic axes of the different rocks, the differences of conductivity in the various component strata may, as with foliation, allow of a variable transmission of heat along the planes of the inclined strata at their outcrop. But, even if that be the case, the effect would be merely local, possibly affecting the mass of inclined strata to a given depth, but in no ways affecting the special problem in relation to the general body of strata unaffected by those local conditions. CONCLUSIONS. The list of selected cases on which these conclusions are based may appear small, but I feel satisfied that the sources of error in experi- ments of underground temperatures are so many and so obscure, that without the fuller information which we have in these few instances, the larger number are not available for our purpose, though they all bear on the general question, and with the corrected data before named it may be possible to utilise some of them hereafter. We now require, however, for this object those observations only which give the nearest possible approximation to the true thermo- metric gradient, and for this it is necessary to reject all the doubtful and more uncertain cases. For these reasons I have confined myself, in the case of the Coal Mines, to the limited number of the eight instances given in the list at p. 24; and in the Mineral Mines to eighteen of the seemingly most reliable rock and spring observa- tions of Fox and Henwood. The Artesian Wells give more uniform results,—results which, under certain conditions, should be perfectly true. I have, however, only been able to select fifteen wells, of which eight are overflowing wells, and seven not-overflowing. ak Prof. J. Prestwich. Taking these three classes of observations we obtain the following values for their several gradients :— Thermometric gradient per 1° Fahr. Coalsmines? oO is cae eee 49°5 feet Mines other than coal............ 43°2 ,, Artesian wells (22.2). 2b os lene 30°0 che. The mean of the three thus gives a general thermometric gradient of 47°5 feet per degree. I do not, however, by any means consider this more than an ap- proximation to the true normal gradient. In Coal Mines the effects of ventilation, and in other Mines the effects of chemical action and the circulation of water, have yet to be more accurately determined ; while in the case of Artesian Wells, I believe the gradient of 49°5 feet may be too low in consequence of the unequal velocity of the water in deep overflowing wells, and of the uncertain measure of convection currents in those which do not overflow. Admitting, however, these determinations to be approximately correct, they show that different geological areas have, in all pro- bability, different gradients, and indicate possible inequalities in the underground isothermals, unless the altered conditions which come into play at greater depths tend to reduce and level them. There is reason also to believe that the conductivity of the rocks at great depths may be affected by their hydrometric state and tempera- ture. The descent of the surface water may ultimately be retarded or stayed by friction and heat. TFaults, although they may stay its descent, leave untouched the water originally inclosed or imbibed. M. Delesse, who made some calculations on the probable depth to which water descends, concluded that water might circulate to the depth of about 8 miles before this limit was reached. Further the experiments of Regnault determined the expansive force of the vapour of water up to a temperature of 239° C., the pressure then being equal to 275 atmospheres. Beyond this, it has only been carried by empirical formule, but both experiment and calculation indicate that, with the increase of temperature, the increase of force is extremely rapid, and there is in all probability a point at which the vapour- tension of the heated water will equilibrate the hydrostatic pres- sure. With respect to the possibility of change in the thermometric gradient at depths, it is known that the conductivity of wrought iron diminishes as the temperature increases, and at a rate agreeing very elosely with the empirical law that the conducting power of iron for heat is inversely as the absolute temperature. What the variation in rocks may be has yet to be determined experi- On Underground Temperatures. 5d mentally ;* we may presume it to exist, although it may differ materially in degree. Therefore, taking into consideration the probable limitation of the percolation of water, and the possible diminution of conductivity with increase of depth, if there should be any alteration in the thermo- metric gradient, at great depths, it will *be more likely to be in the direction influenced by these more or less certain factors, or in favour of a decreased conductivity and a more rapid thermometric gradient, rather than otherwise. I have made a few attempts to ascertain, with the data in our possession, whether there exists any indication of such variation within the limits of the depths reached, by comparing the gradients of the upper with the lower portions of the mines, but without arriving at any satisfactory result.{ It is true that in the Coal Mines, taking a depth below 1000 feet, the gradient, in all cases except two, shows, with increased depth, an increased rapidity, but it is a question whether this is not due to ventilation and convection currents causing too low a reading of the gradients in the upper part of the mines, and so throwing an apparent gain into the gradients in the deeper parts of the mines. In the Mines other than Coal, some show at great depths a more rapid, and others a slower gradient, but it has to be observed that generally there is greater steadiness in the gradients at depths beneath 500 or 600 feet, than in those which are shallower. In Artesian Wells and bore-holes, on the contrary, the gradient is often more rapid in the upper than in the lower section of the wells, but this is clearly due to the action of convection currents; while the decrease in the diameter of the bore-hole with the increase of depth, by unequally checking the flow of water, differently affects the tem- perature of the water in the tubes as successive depths are reached. Looking, however, only at the more certain and determined causes which have interfered with the value of even the best observations, I believe that the effect of them has been to make the readings for the Artesian Wells and bore-holes especially, as well as the Mines, too low; and it may be a question whether a general average gradient of 45 feet per degree would not be nearer the true normal than the one of 47% feet obtained by the foregoing investigation. * The large proportion of iron present in the deeper seated igneous rocks is an, element to be considered. + See the figures between the brackets and in italics in Tables II, ILI, and IV. 56 Prof. J. Prestwich. I. GENERAL TABLE OF | In this Table the observations are placed in order of date. The is generally due to the use of improved methods and instruments, or All the observations are tabulated in the terms of the original papers, rected in accordance with later and better determinations. JI am some of these corrected temperatures (marked m), and for others to ‘Notices Scientifiques’’ of Arago (marked a). In other cases they and additions have also been made for the surface heights. Where the place of observation is given, allowance being made for difference the other columns having reference to the same observations. By an Artesian Well is meant a drill-hole carried down to a deep- face. By bore-hole is meant a boring of the like description, made | A few ordinary wells are introduced merely as guides to the mean if II Iii IV Height of | Mean, : . surface mee Locality. Place of observation. tempera- above ture of sea-level. surface. Feet. Fahr. 1. Giromagny, near Belfort..| Copper and lead mine. . 1535 47°? 2) 73 ee 3) 9 wee! UO 3) 3) - 3) 20 9 >? one Li) 39 bP] >) one 9 3” wo ere PP) 2. Bex, Switzerland........| Salimine™®.......... ne 45? 3. Guanaxuato, Mexico.....| Silver mine........... 6632 67? 4. Cabrera Lore yes eaten ree es ae §510 60? S. Tehuilotepec. 4,,... sn -s0 3 dial d temlavnrs ee 5776 63 ? G6. Micuipampa, Peru....... Me sie: byeiievs alas, eneia ll) AGI 46 ? 4. Freiberg, Saxony........ Beschertgliick lead and 1378 Le ded aoe silver mine ” Tt es OS OLY Oe ee 3) 39 ” >) ” 2s ele ayes Lene Te. Oe. bP} bP) 9) ” -— a ook Re woseee..| Himmelfahri ,, 577 46 ? > ” CET CS ON 9) 99 ” ”? » » CHOSE MCh yt) 9 3 ” ” | me SpA TU eis panenetins Kuh-schacht ,, 656 45 ? 10. _,, - Junghohe-Birke ,, 1050 44? ” bh Maca ee) ae > 39 3) ” * The mine had been disused for three months. On Underground Temperatures. Table L. a7 ox ey, 3) UNDERGROUND TEMPERATURES. (discordance in those observations, which are repeated more than once, to corrections of the mean temperatures of the place. _ with the exception that the mean annual surface temperatures are cor- | indebted to Mr. R. H. Scott, F.R.S., of the Meteorological Office, for 1 the lists of the Scottish Meteorological Society (marked s), and to the ‘are those given by the original observers or by Dove. Corrections | temperature of the place has not been recorded, that of the nearest ( in height, &c. (ante p. 7). (a) in Column VII refers to notes in seated spring, which rises by that means over or near to the sur- ‘either in search of minerals or of water, and with or without water. | temperature at surface or at small depths. Vv VI AVIOL Depths | Tempera- below ture at REFERENCES AND REMARKS. surface. depths. Feet. Fahr ; 1 332 520 On 675 55.4 Gensanne, 1740; Arago, “ Notices Scientifiques,” 1010 66°2 vol. ili, p. 317 (1856). Temp. of Mulhouse, 51°. : 1420 72 } 2 721 6355 Saussure, 1796; Arago, up. cit. me s| 1712 98t » -4 164 63 | ‘ 5 358 75 °R Humboldt, quoted by Arago, op. cit., p. 338. _ 6|{ 1500? Sri} - 3 722 54°5 870 58 984. 60 : ws : Daubuisson. The original observations were pub- 8 328 5O ished % ve RS MEER ae 590 54°5 ished in the “Journal des Mines,” vol. xin, 870 8 p. 118 (1808). The observations recorded here 5 are given by him in his “ Traité de Géognosie,” 9 870 Be || 8 Mi 1819, p. 444, as the most reliable. 10 656 Bare Temp. of Dresden, 47° F. 804. 59 | 936 61 | 1082 625 | + Temperature of spring issuing from lode. The air of the working galleries was 92° Fahr. 58 Prof. J. Prestwich. I iG III IV Height of | "ean, : ° surface aise Locality. Place of observation. tempera- above ' ture of sea-level. surface. Feet. Fahr. 11. Brittany, Poullaouen ....| Lead and silver mine 348 57° (a) ” ” spears ” ” ” ” ” ” see ” : ooh ” [ ” tm Huelgoet ......| Lead and silver mine.. 568 50 bP) ”? LI b>) ) ” 29 9 Ose tay lOO CL Osc ” ” 13. Freiberg, Saxony ....... Alte Hoffnung Gottes.. 1300 ? 43? A Sieee bate ee) cinta ||, ISOLUCIIOIUICE Harel sree tneeemne a er ” ” SiS chenjensnsiieyss ” 9 ” ” ” ” Sie eheueneineleiie ” ” ” ” Wy Wiltiteliaiven am .). 22), cy | MO OGL 00 orm oles ale eee 50—100 $8 48°5 15. Workington ...... ee eet at 5 - A LG?) Perey, Maine aan. sae 5 4 “s 14. Killingworth.... Rata sshwsldiaorediers) anne te Reet nS e. 18. Cornwall ....... wseeee.| Various copper and tin | 700—500 50* mines 9 bP) 9? bP] 3 +) eeeeeeeeeeeeee 93 3° bP) bP) 39 exe ” 99 bP) 2) ” ” ” bP) ” DOT, view oF tine tkes raga onen egbera a Golkeke mioike, bb) oP) ” bP) br) 9 bP] ” ”? ” 3) 9 ES 19 ae Doleoath Copper and tin mine 280 50 9 9) ” +P) 9 2 9 bP] aa bP) 2) ” bP] 3 92 99 3) 99 -)) i) 3) CCN OH) Sh bP) 3 ” bP) ”? oO 09 ” ” 29 ” 20. 3 Huel Worl. ee oe TUR ANTNE am ovate em ie 51 9 - fo Paseo ia Yee Ee) B9) > | Lda ens henge elie eeee ee ” * Tn Cornwall a mean surface temperature of 50°, 51°, 52°, or even 53° F. was | adopted in the early underground observations, and thermometric gradients were calculated on those several different scales. The more recent observations of mean annual temperature, which I have received from the Meteorological Office, give for Penzance 51°8°, Truro 52°, Falmouth 51°4°, while Plymouth is 51°3°, and the high ground of Dartmoor 45'8°. Taking the height of the mining districts to vary from 100 to 800 feet, we may take the mean annual temperature of those districts “in block” at 51°. Mr. R. Were Fox placed thermometers 3 feet underground, at a height of 300 feet above the sea-level, near Dolcoath Mine, which gave a mean annual temperature of 49°94° F.; at 300 feet near Gooland Mine, which gave 48°99°; and at 120 feet at Falmouth, where it recorded 50°67°. His opinion was i te See On Underground Temperatures. Table 1. 59 vV Vi Vil Depths | Tempera- below ture at REFERENCES AND REMARKS. surface. depths. Feet. Fahr. ll 246 gee a) es 2 : | | Daubuisson, “ Journal des Mines,” vol. xxi, p. 119 (1807). = sa he -s (a) Temperature of St. Brieuc. 781 66; 13 2U0 48 °2 De Trebra, 1805-7, ‘‘ Ann. des Mines,” vol. i, p. 377 558 eG (1816), and vol. ili, p. 59. Obs. made in glazed 886 59 niches in rock. The mean of 2 years’ obs. No 1246 66 working going on. 14 430 60 ) 15 504 60 R. Bald, “ Phil. Jour.,” vol. i, p.135 (1819). 48°5° 16 900 68 is the temperature of Cockermouth. 1z| 1200 ; ee AS | 500—550 G55). t.) 600—650 6 Dr. Forbes, “Temperature of Mines,” “‘ Trans. Roy. 700-750 ey Soc. Cornwall,” vol. ii, p. 159 (1820). Average of : 5 observations made in six mines. Grves the tem- 800—850 66 900—930 71 (a) perature of the air and water. These are the water temperatures. 1150—1260} 71 (a) Here there was a strong current of air. 1260—1350] 74 1350—1400] 7 J 19 | 240-300} 58 1% 540—600 59 (a) || R. W. Fox, “Trans. Roy. Soc. Cornwall,” vol. ii, 720—780 63 p. 19 (1820). 1140—1200} 64 (a) r (a) Here there were strong currents of air. Obs. 201380) 78F | in rock, except the last, which was in water. 1380—1440| 82 | 20 6—60 Bape =) 180—240 61 | Ibid 480—540 63 : 600—660 64 < All these are water temperatures. 660720 66 OT es the temperature of the air in gallery was 720—780 70 ‘ 780—840 69 (a) ) that the mean surface temperature of Cornwall was under 51°, and possibly even less than 50°. This will account for the apparent discrepancy between the gradients of many of the original observers and those given in the Tables II, III, IV. ~ A subsequent observation (No. 73) of Mr. Fox, made a year later, at the depth of 1380 feet, gave a rather lower reading. A thermometer 4 feet long was placed in a hole 3 feet deep, at a spot where no workmen were employed, and where the current of air was small. The hole was filled with clay round the stem of thermometer, which was left in that situation for eighteen months, and was found always to indicate a temperature of 76° or 763°. In the experiment of 1820 the thermometer was buried in the rock to the depth of 6 or 8 inches, and filled round with earth. ites a ae : feof, 60 Prof. J. Prestwich. I II tia IV Height of as . . surface 24. Littry, Calvados .. 1.0... ‘ 197 d1t 25. Decise, Niévre.......... m ative atevaye ee Bice 492 D5? 3) Db) eseeeeeeeee 5) eeereeveeete ee ” bb) +b) 3 eeeoeeerdrae bP) eeeoeeereeeteeetee 5) 3° 26. Cornwall, Huel Alfred ...| Copper mine......+... : : 50 2%. 5 Dolcoath......| Copper and tin mine... 280 50 28. Ls Huel Trumpet .| Tin mine ........00. ss 30 29. Pregny, near Geneva....| Artesian boring (not| 808 feet 48 overflowing) above Lake of Geneva 33 9 9 9 39 ” 3) 9 2) bP) > bb) be) 3 bP] 3? bP) 3 3) 9 oe ers 9) 9 ”? 9 %@. Sunderland ............| Coal pit 000.2002. 00- 87 47° 5 SS Tours: s tie semana eter Artesian well. cevesene 180"~ 53 ? (a) 32. Lille (St. Venant)....... * Spell eanbaretwieoeis 79 ad50°5 33. Aire, Pas de Calais...... Re or 50? . 49°F 34. Neu Salzwerk(a). West-| Artesian salt-well..... 270 m48 (b) phalha. Neu Salzwerk pete cic 4 PRU pte rtm a a: ” 930° MS whe el eel ave ” 99 Ow ” ” ” 3” ereeecee ? 99) 1) et ehefe! pia ” ” 35. Sheerness (c) ...........; Artesian well ........ 10 m 49° 2 36. Paris, Ecole Militaire.... a BNA. Dr Ot 213 a dl 34%. Paris, Grenelle Well.... iy 350) eee een Pe a d1tt bP) ) 29 ARs bP) ? th IY, he) 9? ” ) ”? 9) At) ) MOY 4 OO CTO ae Cle 99 ” * The thermometer was here buried for some hours 1 to 2 fect under the ground. + Temp. of Rouen is 50°7°. { Temp. of Geneva, 48°4°; height above sea, 1335 feet. § French feet. || Observation made in hole filled with water. §| The temperature of water at outflow in the first three observations did not On Underground Temperatures. Table I. G1 ys + : Vv VI VII ia Depths | Tempera- : below ture at REFERENCES AND REMARKS. : surface. | depths. Feet. Fahy. 21 | 300—360 Sie 480—540 | 69 600—660 | 70 ; 720—780 70 ~~}! Ibid. All these are air temperatures. 730—840 | 73 840—900 | 70 | 22 540(a)| 62 Jj (a) Recorded by J. T. Price. 23 20 55 33 595 Cordier, “ Essai sur la Température de l’Intérieur 597 83 | de la Terre,” 1822. Temp. of the air in galleries . 630 67 s at Carmeaux 23 °5° C., and at Littry 21° C. ee 325(a)) 61 (a) The mean surface temp. was estimated from 25 29 RAUB | shallow wells adjoining the coal pits. 351 64 | 561 75 ae au 930 79 R. W. Fox, “Trans Roy. Soc. Cornwall,” vol. iii, 24 1440 82 (a) bak (1828). 28 768 65 (a) Air 80. 29 100§ 51°6 ) | De la Riveand Marcet, “ Mém. Soc. Phys. Geneva,” 200 a vol. vi, p. 503 (1833). Thermometer protected 400 - i against pressure. This depth is equal to 713 600 ae ¢ English feet. 650 62.77 30 1584 72°6|| | Phillips, ‘ Phil. Mag.,” vol. vi, p. 446 (1834). 31 460° 6375 Arago, “ Notices Scientifiques,” vol. i, p. 347, et seq. 32 329 57°2 j (a) Overflowing spring. 33 205 55°9 || Arago, “Not. Scient.,” vol. ii, p. 347 e¢ seq. 34 787 10°79 | (a) Recorded by Humboldt. 1033 73 r (6) Temp. of Boehum, which is one degree further 1073 81°5 | south, is 48°6°. The boring was ultimately carried 2038 38513) ) to a depth of 2113 feet. 35 361 60 (c) No reference given. 36 568 615 Walferdin, “Comptes rendus,” 1836, p. 314.** : a4 ie HG f Walferdin, ‘Comptes rendus,” 1837, p. 977; and | 1656 79°6 #Sego. a! agree with the temperatures at depth (which are those given here) owing probably | to the influx of water at intermediate depths. ** All Walferdin’s observations were made with overflow thermometers pro- tected against pressure. ++ Temp. of Paris. Another datum line of invariable temperature (53° F.) at the depth of 28 métres (92 feet) in the cellars of the Paris Observatory, is sometimes taken. Prof. J. Breseaiehn Locality. | $%. Paris, Grenelle Well . 38. 39. 40. 41. AZ. 43. 44, AS. 46. 4%. 48. 48a. 49}. 49c. 49e. A9f. 499. * Nos. 49a to 49p are from Mr. Henwood’s paper, ‘Trans. 49. 497. 49d. Cornwall, Levant ...... a Tresavean .... a Consolidated . Rudersdorf, Berlin.. II III Hast of Place of observation. surface above sea-level. Feet. Artesian well .ssesers 213 Copper and tin mine .. 8&0 Copper mine .....+.0.. 362 +B) +} ) eeeeoe#ee#ee#ees 818 Artesian well ?2...0..+. 153 Artesian boring..... 128 St. Sever, Rouen.. St. André (Eire) Yakoutsk, Shera 9) 39 oy) ” e@eeovevesd Scotland, Garse of Falkirk. ”) 3) : Midlothian.. Cosseigne- les- Luxembourg Cornwall . Troyes, Aubein’ soa St. Ouen) Paristiss sive Alfort, Marne . Cornwall, East en Crofty.* ‘Cornwall, Consolidated . 9) United Mines. . 29 Grcat Wheal For tune. Cornwall, Marazion 9 ”» Artesian well ........ ” Artesian bori ing BY vot ee Various tin and copper mines ” bP) Artesian MOTE Tate im Weave 359 of Copper and tin mine. ») ” | oy ee des a | i ‘ Wheal Trenwith Copper fittest) Ae 3) x South ’Roskear, Cambourne. ” 9) Cornwall,” vol. v, pp. 3889—402. Arago gives a depth of 377 feet with a temp. of 31° F. IV Mean annual tempera- ture of surface. Fahr. a 61° 50 Roy. Geol. Soe. On Underground Temperatures. Table I. 63 37 =e 39 40 41 42 43 44 45 46 44 48 48a 49 49a 49b 49 49d 49e 49f } 499 Vy Depths below surface. Feet. 1797 1380 1572 1740 880 600 246 830 50 77 119 182** 231 270 380? 1105 354 438 684 43 0t 216 177§ 480 810 1704 1764 1080 1260 804: 864 222 480 600 180 660 702 774 834 VI Vil Tempera- ture at REFERENCES AND REMARKS. depths. Fahr. z 81 °o2 {| Walferdin, “Comptes rendus,’ 1837, p. 977; and | 9 Arago. 80 3 Henwood, “Report Brit. Assoc.,” 1837. 3 Thermometer buried in rock. 850.3 74.°3 Bischof, “ Edin. New Phil. Mag.,” vol. xxiv, p. 132 (1838). 63°7+ | Girardin, ‘‘ Comptes rendus,” 1838, p. 507. 54°5 Walferdin, ‘Comptes rendus,”’ 1838, p. 503. 64.4 Pp p 18°5 Z e Erman, ‘‘ Comptes rendus,” 1838, p. 501. 31 = : R. Paterson, “ Edin. Phil. Mag.,” vol. xxvii, p. 71 53 (1839). ig Only the rate of increase given. 78 Biver, ‘‘ Comptes rendus,” vol. x, p. 41 (1840). Fox, ‘ Brit. Assoc. Rep.,” p. 310 (1840). Average of 53 mines. Only the rate of increase is given. ee In these cases,see Table IIT. 60 Walferdin, “ Bull. Soc. Géol. France,” vol. xi, p. 29 (1840). 55°3 Arago, “ Notices Scientifiques.”’ Ls ice: Lassaigne, “ Comptes rendus,” October, 1842. 61 Small stream from lode. 90°47 Small stream from rock. 89 Moderate stream from lode-end. Pets Large stream from lode-end. 74 Very large stream from cross-course. 89 °5 Moderate stream from lode-end. ie } Large stream from rock. 56°5 Moderate stream from lode-end. 63 Large ” ” ” 66 Small BS Ps ais Small stream from lode. 66 Large ” ”? ) 62 Moderate ,, * Re oe | Selle Ate) 1° 71 + Thermometer not protected, but pressure allowed for ; remained down 16 hceurs. ft The last 107 feet wer2 obstructed, so that the actual depth was 517 feet. § Water overflows. 64 Prof. J. Prestwich. I II III IV | Height of Sen surface cbues Locality. Place of observation. tempera- above sea-level ae 5 ’ | surface. | Rivers onianer Our Pinter BUEN” | Feet. Fahr. | 49h. Cornwall, North Roskear.| Copper mine ........ Be 50° 9 99 bb) oe) eerse ee eve ee 39 | 9 ” 99 99 eevcecvece ee 39 ' J ” 5) ” ” one p 0 es 492. 9 East Pool eeoe 9 Oy e ee 39 : 99 99 eeee by) 99 eooeesee eo 39 49). 4 Wheal Uny,| Din mine «oss io caceur P i Redruth. 99 99 99 ee aeeveere ee ee ee > 49k. Cornwall, Chacewater, . wa Se. ace, hea “ak ve Redruth. 9 99 99 eat ee Car acts CS ee +b) 491. Cornwall, East Wheal| Copper mine ........ we * Virgin Consolidated Mines, Redruth. ” > bb) ” wets Os) ” 49m. Cornwall, Wheal Towan, i a oi : - St. Agnes. bP) 39 9 ” eeceecvecee ee ” 49n. », Wheal Prudence ns at OSs arenes A ” 4Qp. ., Wheal Vor ...| Copper and tin mine... ci Sib a9 : 99 ” 99 yh ee 3”) 50. Cornwall, Binner Downs .| Copper mine.......+. 5 50 bb) eeeeoeeswrteeoeeeeee 99 eeoeeoeeert#e8e6 ee 33 9) eenee@nene re e@eeeveence ”9 eeeoeervree ae ee by) } bb) ee@eeve@eeeveeeesvse eee 99 eeeecsve58e8e8es ee 59 9 ae Sole, (8 ie sie) ei su ese ieee ” er7m~weeeeeee ee 99 51. Devonshire, Wheal Friend- sre mabe.cieyals te ate » ship. >}s) eeeeereesesesee 99 ee@t@eeeeee#ee e a 99 eeeoeeeee@ee @@ @ by) eeeeeeee8ee ee 59 09 eevee ere ee ee Oo 9 See ig sac ee can io Bh) 52. Cornwall, St. Ives Consols| Copper and tin mine... : 51 39 e@vevece @eeovesece oy) eee ee 99 oy) @eecrecere ee .@ ee ee ” eee ee 59 9 eeceeoeveeve ese ee eee ‘ 9 ees e 99 53. Cornwall, Wheal Wreath.| Tin mine .esesereeess ove » 599 eeeeevoseseseoeeee eee 99 @eeseeeveeeeeee ee bb) ewe OG, Cheb XN ORCA EO eoee@e 9 eeceoeeeeve se ee ee bb} | 99 eeeeceveve eee ee 99 eeoeoeoeseeve ee eae ee 3° Oy ” eeceoeeoe ee ee oe e 9 | 54. Cornwall and Devon.....| Various tin and copper 5 50 | mines | ” I 2.21239 ” ” a eve 33 ”> 59) nuevas iene) ” 9 ee ee "Ps ) i 5) 9 ee cee 99 99 ee ee ” 55. Monte Massi, Tuscany* - Shaft aaa Oe 174 56? | ” 9 ” eee ” ee eteoeeeoe ee te oe ” ” * No water. Shaft well ventilated. An abnormal centre of heat in this district. a = 49h 497 49) 49k 49/ 49m 49n 49p a2 53 55 On Underground Temperatures. Table I. 65 V WE Depths | Tempera- below ture at surface. depths. Feet. Fahr 402 61° 642 66 786 60°47 822 Ti 372 59 »” 58 5 390 58°3 432 60 486 61°5 768 ols %9 68 53 72 1500 86°5 1722 94.°5 ” 92 9 GI 648 62 804. 40 924, GP 654 65 °5 1420 80 °5 \ 1706 gI 300 BET) 756 64 | 816 65 936 7475 | 1056 82 l 282 pean 450 54 | 690 64 810 69.75) 108 57 642 60°5 462 65 810 71 162 ES san 1242 70 1422 41°5 | ” 75 | 1482 OI 180 Bes 3) | 432 60°8 L 762 Cig) ETE 1050 48°6 ] 1440 85 °5 1122 103 1214 107 VOL. XLI. VII REFERENCES AND REMARKS. —— eee Small stream from lode. Large ” +P) +e) Large stream from cross-course: Large stteam from lode. Large stream from rock. Small stream from lode. Large ,, ae wee) Small ”% oD) oe Small stream from rock. Large stream from lode-end. Large stream from rock. Small stream from vein. Hole in rock. Moderate stream from lode. Small stream from rock. Small stream from lode. Large stream from lode. Temperature of rock. Henwood, “Trans. Roy. Gecl. Soc. Cornwall,” vol. v, p. 389 and 402 (1843). The observations in all these mines were taken in springs issuing from the lode or rock. Ibid., p. 387. Ibid., p. 402. Average of various mines in ten districts. Matteucci, ‘“‘ Comptes rendus,” 1843, p. 937; 1845, p- 816. 66 Prof. J. Prestwich. I II III TV Height of | "02, . . surface i ines Locality. Place of observation. tempera- guano ture of sea-level. | — surface. Feet Fahr 56. Neuffen, Wurtemberg* ..| Shaft and bore-hole.... 1878 46°? 59. Mondorff,+ Loxembong. Artesian well ........ 672 47 ? A Malcwnete cere e jy) ae ieee a n e eee | oi agg) ho, ee ae ; 58. Mons (Couchantde Flénu) § Coal pit .. ate breacareee f 5&9. Hastern Virginia, U.S.,| Coal pits............ a 36°7 Mills’s Pit.|| 60. Eastern Virginia, U.S., pes rs ba Se aby, ee ae : Bs Wills’s Pit. 61. Eastern Virginia, WES: i *: ie Rea i: i Midlothian Pit. e eMart oh The ool LE er sree ans A 3 G2. Meaux, Marne ......... Artesian well......... =H 51 63. Ostend, Belgium........ - & ; 20 m 50 Ga. Vienna... s.s'cesse. nme: - ae. Rae 637 m 50 65. Mondorff, Luxembourg.. is Ses aikpts Bi eh aes 584 47°53? 9 9? 29 bP) SSP e nee mens bP) 3 GG. Charleston, U.S.A...... ‘ wait lene Cen ee 20 m 66 3) 99 9 Iie RSE Ape. (Sh BLOTASES, bP oP) ” ” ” ” ch] ” ” 3) ” +) +9 sik eo 3) ” 6%. Conselica, Ferrara, Italy { i vai tetas eet 27 m 53°9 GS. Creuzot (Torcy) Sadne et | Bore-hole ........000. 1017 48 *5 Loire. ** 69. Creuzot (Mouillonge) .. sy nistaiateastare peeteeste 1052 Ps 70. 1837. Comma lin MUNG ‘aaa iors a bod 08 wa 51 31. 1837 Pa Copper Mine 1.2.0.0 a6 ‘i 42. 1837 », Botallock. i; Shi th oavasayel Gaerne 40 51 * The abnormal temperature in this boring is attributed by M. Daubrée to the proximity of masses of basalt of post-miocene age ; and by which basait the adjacent rocks have been altered. The surface temperature of Tubingen is 8°7°C. The temperature from 30 métres downwards marked 38°7° C . + The water overflowed from a spring met with at a depth of 450 métres. Bore- hole continued to further depth of 730 métres. Thermometer not protected. { Temperature of the water which overflowed at this level. § Temp. not given: only the rate of increase of 1° C. in 33°25 métres. || At Mills’s and Wills’s pits the temperature given is that of the water collected at bottom of shafts. On Underground. Ti emperatures. Table I. Vv VI VII Depths | Tempera- below ture at REFERENCES AND REMARKS... surface. depths. 67 Feet Fahr 56 1263 101° Daubrée, “ Comptes rendus,” 1845. Yr | 1476 gana 2200 On 72 Rivot, “‘ Ann. des Mines,” vol. viii, p. 79 (1845). 2297 2 § | 58 Bp ie “ L’Institut,’ April, 1845. 59 420 6a) 60 386 62 | 570 OBIE Professor H. D. Rogers, 1846. Observations in 61 330 61°7 | Report on Coal Mines of Eastern Virginia. 600 66°2 | 780 68°7 ) 62 230 Ba 2 D’ Archiac, ‘‘ Histoire des Progrés de la Géologie,”’ vol. i, p. 77 (1847). 63 967 a1 6 Dewalque, “‘ Bull. Géol. Soc. de France,” vol. xx, p. 235 (1849). 64 616 60°8 “‘ Bull. Géol. Soc. de France.” 65 1647 = |(a) 78°3 Walferdin, “‘ Comptes rendus,” 1853, p. 250. 2362 = |(0) 81 °7 (a) Temp. of first overflowing spring. (6) ,, of the mud in bore-hole; this is un- : reliable on account of convection currents. oe i oF | Hume, “Edin. New. Phil. Journ.,” vol. lvii, p. 178 400 (1854). Nothing said about protection against 1000 La pressure or convection currents. Observations 1106 oe 5 were taken at every 100 feet. 64 164 59 Searabelli, “ Bull. Soc. Géol. France,” vol. xiv, p. 102 (1856). 68 1817 81 Walferdin, “‘Comptes rendus,” 1857, p. 971. 69 2677 100 ae ie 74 R. Were Fox, “ Brit. Assoc. Reports for 1857,” a1 1248 84 p. 96.47 52 nee) Oye (a) Under the sea—gallery quite dry. § Water rose 2 métres above surface. ** Highteen protected thermometers used. The boring at Torcy had been sus- pended for six months. The observations at Mouillonge were made only after one to three days’ rest. The two borings are 1500 métres apart. ++ Most of these experiments were made at or near the ends of the deepest levels of the mines. Casella’s thermometers were used in the later experiments. were placed in holes 15 to 20 inches deep in the rock, which were carefully closed with clay, tow, or cotton. Thermometer left in for + to 1 hour. F 2 They 68 against convection currents ; "+ The surface temperature of Manchester is M 48°6°. Locality. ——_ —— ee 43. 1822. Cornwall, Dolcoath 44.1857 if 45.1853 _,, . 46. 18528 it Levant Ga. ,, a SA 44.1857 é 38. 1837 - Tresavean 49.1853 _,, “ $0. 1853 is United or Fowey Consols. $1. 1857 % oh $2. bb) 9 bb) eB: Olt ee wee he SIR 84. Columbus, Ohio, U.S.A.*. 85. Dukinfield, 1848. me Makiaticld) 1658/0 e. 0 bP] 9 8%. Rehme, Westphalia se 88. Louisville, Kentucky§ 88a. Sahara Desert.......... 89. Naples, Largo Vittoria]. . 90. __,, 91. Ben Tallah, Algeria .. 92. Baraki, ee oes 93. Oued-el-Halleg, ,, Royal Palace.... Prof. J. Prestwich. IT Place of observation. ee a Copper and tin mine.. 39 bP] Another lode........+. Copper and tin mine.. 9 bP) 39 9) Copper mine...... Ocul Shafi Gaon eeecerve ee wea III IV Height of | 7/020, surface t empera- above a ture OL sea-level. surface. Feet. Fahr. 280 50° ee ” 80? 51 362 50 bb) bb) 51 3656 BE 834 m 53°83 br) 48+ bb) ; 48 -6t * Walferdin’s thermometers in strong iron case were used, but without protection left down 28 hours. { This is the temperature of Boehum. Dukinfield stands higher. On Underground Temperatures. Table I. 69 v Vi VII Depths | Tempera- below ture at REFERENCES AND REMARKS, surface. depths. —————— fee. Feet. Fahr. 43 1380 76° > 44 1632 73 | 5 . g = une R. Were Fox, ‘“‘ Brit. Assoc. Reports for 1857,” 46 15380 |(@) 74 p. 96; also ‘Coal Commission Report,” vol. ii, [oy ea las aoe 2 2) 87 (a) Near bottem of shaft. cir | 56 (ce) 85 - (6) Not far under the sea. 8 : | (c) Far under the sea—no working going on. a ls ae (dz) A copious spring of water here gave 98 5°. 49 2112 |(d)90°5 | (e) A hot spring in another lode. sO 1728 93 | 81 1530 ford, 5) $2 = (e) 116 83 288 64.°8 | Henwood, “Edin. Phil. Mag.,” N.S., vol. vii, _ CONS! p. 147 (1858). The mine is 1500 feet deep ; well ventilated. No water: rainless district. Obs. He62 a : J in holes in rock 2 feet deep. 9) 84 90 53 } Wormley, ‘“‘ Amer. Journ. Science,” 2nd Ser., vol. 2575 Seer 2) xxx, p. 106 (1860). 85 17 51 711 58 ae = Fairbairn: ‘‘ Brit. Assoc. Reports,” 1861, p. 53. ; - Observations made in holes on side of shaft; ee 87. UN th left from half an hour t 1734 a: r thermometer left from half an hour to two hours. The holes all dry and mostly in shale 2151 y J S6 502 2 or rock. No mention of temperature of air in 5 the shaft, or of the depth of the holes. 924 60 1000 62? 1401 66°5 J 87 2280 88? Fairbairn, “ Brit. Assoc. Reports,” 1861. 88 2086 83/5 Delesse, ‘“‘ Revue de Géologie,” vol. i, p. 9 (1862). 88a 56 oe Only the rate of increase given. See Table IV. 89 909 71°6 | Mallet, ‘“ Neapolitan Earthquakes,’ vol. ii, 90) 1460 cq, J| — p-811 (862). 91) 459 76 : L. Ville, “‘ Ann. des Mines,” 6th Ser., vol. v, p. - oO 77 369 (1864). Overflowing wells. 93 371 734 § Overflowing salt water; said to rise 52 métres above surface. || The water rose above the surface. § Attributes this low temperature to the influx of water at different depths. ** The mean temperature of Algiers is 64°5°. » Locality. ————-s ———————— ————————— ee Prof. J. Prestwich. 94. Reggio, Italy ........ 95. Ghadamés, Tripoli...... 96. St. Petersburg ........ 97. Messis, Algeria ........ | ” Ci ae Oe eOn CRON 98. Meiahadalon, Algeria.... 9 2”? 9 ? 99. Chega, 5 100. Bothwell, Ontario, U.S.. 101. Rochefort, Charente Inf. . 102. Virac (Tarn) 103. Montigny, Belgium ..... 104.|| Pendleton Colliery, Manchester. 105. Hucknall Torkard Col- liery, Nottinghamshire. 106. Annesley Colliery 10%. Kiveton Park Colliery ,, 108. Swanwick Colliery 109. Moira Colliery, Warwick- shire. 110. Ruabon, North Wales * Temperature of Messina. + The rate of increase is given at 1° C. in 30 to 31 métres. No other particulars. { Water rose above surface, at rate of 700 gallons per hour, from the Corniferous Limestone. 99 29 II Place of observation. § Temperature of air in gallery 68° F. || Nos. 104 to 122 inclusive are from the Royal Coal Commission, 1866-70, vol. ii, “Report on the Possible Depth of Working.” {| This was in the floor; temperature in coal 70° at a distance of 500 yards from the down-brow. In the same level 1000 yards from the down brow, the temperature was 83° in the coal, and 82° in the floor. Ti" 4 IV Height of | _ pee surface t saute empera- above ture of sea-level. surface. Feet Fabhr. 65 °5°* , 73°4 15 m 38'6 68 P 3 i} bb) 45? wre 54°5 705 55? 51 126 m 48-6 b)>) ” >) ”” 9” Jy) s 48 9TT e by) oe ” 460 48 48 °5 420 48 bb) ” $))) ” +)) ” On Underground Temperatures. Table I. 71 v ME Vil Depths | Tempera- below ture at REFERENCES AND REMARKS. surface. depths. Feet. Fahr. 94 2297 + “Revue de Géologie, vol. iii (1864). 95 394 84.°2° bb) 3) 9? ” 96 525 50°5 Ibid., vol. iv (1865), the water overflows. 97 144 69°5 >) 277 41°6 | Degoussée et Laurent, ‘‘ Revue de Géol.,” vol. iv, 98 67 75 p- 25 (1865). Discharge of water per minute, 193 46 respectively 150, 1200, 15, 50, and 270 litres. 263 Tighe 3 99 138 43 “4. Ibid., p. 26 (1865). 100 AT5t Ph { pay ee “Chem. and Geol. Hssays,” 1866, 101 2812 Ue Letter from Mauget and Lippmann, Paris, January, 1872. Overflowing mineral water. 102 971 84.°2 “Revue de Géol.,” vol. viii (1869). Overflowing well. ..¢J | W. Warington Smyth, ‘ Quar. Jour. Geol. Soce.,” mes | 2180 75°48) |” Aol xxiv. p. 81 (1868). nA TORU 74 | “Coal Commission Report,” vol. u, pp. 90, 192, and 199. lee ie | The work here had been open six years. 2214, ae i] Work here had been open six months.tf 105 1250 70 ‘Coal Commission Report,” vol. ii, p. 96. A new pit. 106 1425 73 2 33 +) 10% 1200 71 is 33 »» 108 966 62°5 s a Very wet shaft. 109 | 1030 Hoy . E 110 1002 608§ Ibid., p. 104. Temp. of air in gallery.. 58° 1503 7O°S ‘: 33 3 2. | 8rd 1605 73 ” ” ” O° ae 1770 78 ” ” ” ac 71 ** At 200 yards from the down-brow, the temperature was 80° in the coal and 84° in the floor. At 400 yards it was 82°in the coal and 86° in the floor. Ina tunnel at the same level, the temperature of the shale was 76°; further on in fireclay it was 79°, and still further in hard rock 82°. Holes from 3 to 4 feet deep. Thermometers verified at Kew. Left 3 to 12 hours in holes perfectly dry. t+ When open one year the reading gave 84°. {tf This is the mean annual temperature of Nottingham. §§ This observation was not taken until long after the pit was sunk, and coal evidently cooled. "2 Prof. J. Prestwich. I II TT IV Height of wee surface annual Locality. Place of observation. . tempera- above ture of sea-level. surface. Feet. Fahr. 11. Norley Coal Co., Wigan ..| Coal pit ............ 157 48° oy) 99 3° eeneeeee eee @ > 99 39 93 a9 39 bP) a9 99 99 29 : 39 oe 112. Aberdare, Upper Duffryn* 55 sienalt iota etehete 400 48 °5 Colliery, No. 1 Station. 3 Sh aaa Pe Me iit oko 1220 35 . a erOATE Ts, 5 a icyetegeye ile aoe 1330 aie 55 Spee Aer is ci ice ehavetonetcene 1540 | on 113. ,, New Tredegar Colliery,+ n ite Rusia’ inten eee 720 48? No. 1 Station. i pe Li te sy po her AGientey sfavern scien 679 ‘ ‘% Ba eed yl Whigs Bact pete Bshevepanevs 1495 ae 5 Wn? Re aon ‘3 atte a tore terres 1287 A 114. ,, Dowlais Colliery, Iron- Behe si ga ee ateners icles 1170 47 stone Mine. ”9 oe) = COR Wea ee Ch Op Cinta ye Cir SOs Crt} .O ‘ 99 * 99 MMs. 4, Cavimlbbachs tae seat on FB aie Sratreiia acannon Goel 480 48 °5 3 53 Shileeee ers Gtatere NMR seen eieseroes 1300 59 116. Hetton Colliery, Durhamft i Teutofekeiehs topes 400 - 478 ” ” ” MF 1.9.9.0 9.0.0,0'9'0'9 0.0 ” ” ” ” ” ” VO 99D 0Q0 O ” ”? 39 9 99 39 99 99 99 39 9 bP) Soe Oe kenies ieee /eresene, 9 be) 99 33 +9 ID gery Pr Mietimete wc eene ee cke, relieate: O10 9) 9 ai i bs R Bo icilicts Go 33 a 414. South Hetton Colliery, 5 sia voveremate Mion 204 ‘ Durham. 99 9 93 39 e ve 9 3 RS i - St edi Sicha : 4 118. Rosebridge Colliery, Wigan ‘ dd doba 064 157 48 ” ” ” MP BOO R0 OG 8.09.0 ” ” ” ” ” DS O98 0/0-070,,0.0" 0'0 ” ” 9) 9) a9 ” Q bP) 2) * Beyond No. 2 station the circulation of air was partially stopped, and beyond No. 3 station entirely stopped, that part of the colliery having been abandoned for 18 months. The other Aberdare experiments were in collieries that were working at the time, and the air not shut off. The temperatures taken 4 feet deep in the coal. ‘ + Although the surface at No. 3 station is 124 feet lower than at No. 4, it is: 112 113 114 115 116 11% 118 Vy Depths below surface. On Underground Temperatures. Table I. VI Vie Tempera- . ture at REFERENCES AND REMARKS. depths. Fahr. _.o )| “Coal Commission Report,” 2 | p- 104. Temp. in gallery.... iy le r 3) bP) +S) ee 72 a | >») bP) +»? 73 2 D ” ”? ” 70 3) Distance Ibid., p. 105, et seg. Tem- from shaft. 61 perature of air in gallery.. 62°F. 27 yards. 65 = 53 =< 66 LSSZ~ * 5 68 : i a0 OG TSG 75 » » -- &4 2327 — y, 58 L 3 Z -- 60 TO <;, 63 | fe is eNO 570, 69 3 Ss Roar A! 2090.) | 67 es 3 ue. §2 1320), 56 7 5 wee O 59 2 .» 58 55 : 61 Distance ‘| | Zord., p. 123. eee of from shaft. 60 air in gallery....... 50° F. 312 yards. 68 S ie soa 00 1935 ,, 63 ¥ £ SO EBS Bue Deon 65°56. | Fe iJ So és! 2980 ,, 66 i» i ..» 62 1640 _,, Ae i ? = in the 4332 ,, 70°5 J = 55 far (28, 3000!” 5, 72| 82 Ibid., p. 123. 96 pp: 5 i Ibid., pp. 148 and 188. All the holes were 1 yard 3 \ deep and made air-tight. Holes allowed to stand H | 8 hours before thermometers were put in. 83 J Thermometers left 30 minutes. further in the heart of the mountain, and the rise of surface at No. 4 is very abrupt. Temperatures taken 4 feet deep in coal, in dry holes and no gas. _ Holes in coal 3 feet deep, filled with water, and left 48 hours. Thermometers _ then placed in them for 24 hours. § The mean annual temperature of Durham is 47°1°, and of Seaham is 47 °7.° | || These temperatures were taken after boring operations had been suspended || about a week ; bore-holes full of water. ca | 74 Prof. J. Prestwich. | I le | | III IV Height of ea j ; surface ance Locality. Place of observation. A tenipera- ture of sea-level. surface. Feet. Fahr. Rosebridge Colliery, Wigan| Coal pit ...........6. 157 48° " oH) 3 ) DD). 8) Fe eee et ear eae Ne ” 99 99 3) 39 39 3%) ed iseneatastor aid cae DL) Bt 33 99 39 bP) 33 bP) ”) aCe aa eee be iC pC) pp) 39 3) bP) 2) >) bb) * 33 ” 39 99 99 9) 29 chy) 3) bb) 3) 399 99 39 39) Ly) bP) 2) 39 x) 9 ie bb) 9 119. Sharlston Colliery, Barns- sith site? wey eu aie lava tole apes 240 we ley+ 120. Victoria Colliery, Wake- Lie ihgig. Riga teteban ensue eR ORR 140 m 48 °5 field. 121. Worthington Colliery, Lan- See kei uetusne ee henaone 2 48 ? cashire. 122. Ram’s Mine, Lancashire, ee Bitlet 175 486 Pendleton Coiliery.§ ” ” ” MD B. S809 09 99 2000 ” ” ” ” ” I. 2D 90990005 ° ” ” y) 9 ” 3/9 pan o)9) a ne emeneneniefe\ neh ee 9 ” 122a. Cornwall, Tresavean|| ..| Copper and tin mine... oe 50 1234. Blythswood, nr. Glasgow] Bore-hole..... fatol eter sores P m 47 ** oh) 99 ° 59 e@eeeeee eeeeeee ee 99 39 99 c 399 eeoeeeteeeeeeeee ee 99 124. South Balgray 99 e 99 eeoeesveeeee eee P 99 ” 99 bP) bE) peda hE) Hey CRs 0 ” ” 29 99 a9 ba AE i nae oo Ca ” 59 5) 99 e 99 eeeeevsvee# eeeevee oe 59 125. Carrickfergus, Belfast....| Salt pit shaft ........ Ps m 48 S++ 59 eeeeoeveaeeeteee 99 99 eeetteee ee 99 126. Rosebridge, Wigan......| Coal shaft............ 157 | ss 48 93 399 eeoevce#e 99 eee e@eeeneo0eseee 99 99 9 99 ° e 99 @erereeeete ce 9 9 ” ” ” aie C 29 ” ” 9 99 eeeeoe 9 e@ecvce ee ee oe oo 3 9 124. St. Louis, U.S. America..| Shaft to 71 feet, then a 481. m 55 as Hi AM ka bore-hole ...... see by - 128. Mont Cenis Tunnel...... S548 05 9529 Af Soe * The air at this depth was 18 to 22° lower than the rock temperature. + The holes in this and the following pit were in coal and 2 yards deep, and perfectly dry. Thermometers left two days. { This was the temperature of a brackish spring issuing from a grit rock 2’ 9” thick met with in sinking the shaft, and discharging about 1600 gallons per hour. § These observations were taken two years after those of Mr. Knowles ; the first three were made in holes 3 feet deep. On Underground Temperatures. Table I. 75 wo v1 VII i | Depths | Tempera- below ture at REFERENCES AND REMARKS. surface. depths. | Feet. Fuhr. 1989 Sia. ZO a7 “Coal Commission Report,” pp. 143 and 149. All | eed oe the holes were 1 yard d d made air-tigh | 9935 89 e holes were 1 yard deep and made air-tight. 9983 Be L Holes allowed to stand 8 hours before thermo- 9399 7 e 5 meters were put in. ‘Thermometers left 30 2349 a > minutes. 2400 93* Distance eee ee & from shaft. Ibid., p.157. Air in gallery.. 63° 270 yds. 120 1455 78 5 ” 65 600 ,, 121 1803 82t Lbid., p. 194. 122 1944, 92, Lbid., p.199. At 300 yds. from engine brow, 3 feet deep. le 2088 78 At 50U yds., hole 3 feet deep. | Pt 82 At 1000 yds., hole 3 feet deep. 2214 84 At 930 yds. from brow; hole 7 ft. 9 in. deep. 122a| 2130 99 Ibid., p. 85. Dry level hole, 4 ft. deep. 123 60 47°9 180 50's Brit. Assoc. Report of 1869. Water in bore-hole. 347 Bae 124 60 48°2 180 aaa Ibid. Original depth 1040 ft.; bore-hole silted 360 554 up to 526 ft., and full of water. 525 59°5 “Aad es a 4 } Ibid. A few feet of water in both shafts. Tang ioe oe ? || the temperatures (except the first) were taken 1989 P | during the sinking of the shaft by drilling a 2935 ee r hole to the depth of a yard, plugging with clay, | 2445 Fe ; and leaving the thermometer % an hour. = pon te Brit. Assoc. Report of 1870. Better data wanted. | 128 5282 85 "1 Brit. Assoc. Report of 1871. | || Coal Commission Report, A 4, vol. ii. , §| Nos. 123 to 165a@ are from the reports of Prof. Everett, Secretary of the Com- mittee of Underground Temperatures, in “Trans. Brit. Assoc.,” 1869-83, inclusive. ** Mean annual temperature of Glasgow. ++ Mean annual temperature of Belfast. {i This is the estimated mean temperature of the surface summit level. 76 Prof. J. Prestwich. I IL III IV : Mean Height of | annua Locality. Place of observation. ° | tempera- above sea-level Sand " | surface. Feet. Fahr. 129. Kentish Town ......--.. Artesian well ......0-- 187 49° 9 » 33 33 PAN | Senne 33 3) a ao) Meehan es ea _ 3. FS eee “ - 33 9 hh as ” 33 9 33 130. Allanxheads, Northumber- | Lead mines.... 1360 ? s 44°2 land (Gin Hill Shaft) 3) 9 33 + )> aged i calc gd ~ Bcxie mh, — — 23 131. Allanheads, Northumber- ef x * land (High Engine Shaft) 132. Allanheads, Weardale, a “3 -- 45°3 Slit Mine 133. Allanheads, Breckonhill : thy weke eee 1174 44? Shaft 2) 3) b> 99 at shia ” bb) 134. Crawriggs, near Glasgow.| Bore-hole ...... 200 47 3 3) 3) ne 33 33 bb) 29 3) 3) ” / 135. Moscow a: 466 a 39-5 3” p) ee. se) @ 0 sre) \s Bien ya's i >” aevssoeooe'a ge 880880 33 33 136. Durham, South Hetton | Shaft and bore-hole.... 100 ? 47°53 Colliery 39 ” 33 3 33 2) 33 3) 3 32 33 33 3) 39 13%. Paris, La Chapelle St.| Artesian well ........ ae ay Denis »”»? > 33 33 7G ee elit Mat ind 2 = > 39 >) 33 3) 3? P= 33 138. Stowmarket............ 5 Pope Pie 185 549-4 | 9 3) 33 3) 33 139. Przibram, Bohemiat ....| Adalbert silver mine ? 44°7? 9 3) 9 3 me =p j ry) ” » ” ° es 9 33 By ” ~ te! | 140. Seraing, Liége, Marie) Coal pit ............ 1ST @ m 51°*1 | | Colliery ) | - 3 a Se BES ior on: ss Be | | 1Al. » Henri Guillaume 5 = 9 | * Subsequent observations made in 1879 established a temperature of 67 ‘06° at 1008 feet. + The thermometer could not be sunk below 857 feet, but the shaft extends to the depth of 957 ft. On Underground Temperatures. Table I. cui > Vi VI VII Depths | Tempera- below ture at REFERENCES AND REMARKS. surface. depths. Feet. Fahr. 129 305 Om ne) 500 60 || These are the results* of repeated observations | 700 62.78). commenced in 1869, by Mr. G. J. Symons. 850 65 Rate of increase down to 910 ft. is 56 ft. for | 1000 67°8 1° F. Below that 49 ft. for each degree. 1100 6y"9 J 130 340 49 °3 : : 3 | Water stands in shaft at 328 ft. No reliance is | 390 Rls placed on this determination. | 440 51°3 131 857+ 65°7 Water stands at 797 ft. 132 660 65 "1 Shaft full of water. 133 42 46 °5 Water stands 24 ft. down shaft. Unreliable. | 342 46 °6 { 134 50 47 ; : ; : 200 50 No weight attached to this determination. | 350 I | 994 Ef \ Same temperature at all depths. 136 1166a ee a. 100 feet deep in bore-hole. Brit. Assoc. Report of 1872. Shaft is 1066 feet deep, 1466 ae and bore-hole 863 feet. Total depth 1924 feet. 1736 7% 13% 2 595 Brit. Assoc. Report of 1873. The diameter of this bore-hole is 4 feet. Convection currents inter- Esl 69 fere with these results. 2165 76 138 100 53 Original depth was 895 feet. Blocked. Uncertain 283 54 \ results. 139 621 Sor 7 Brit. Assoc. Report of 1874. Observations made in 1209 Dee holes 2 feet deep and far from the workings. 1652 One Temperature of air not given. | 1900 61 ‘4 lord =" ie My Temperature of air in gallery 773° F. Obser- | 1017 78 vations made in holes 5 métres deep. Thermo- meter left 24 hours. 141 1656 87 | + The section of this mine shows fifteen shafts. Herr Grimm attributes 1 o the slow increase of heat to the rocks, which are of Silurian age, being very quartzose. 78 | Prof. J. Prestwich. I II Iil IV Height of | Mean, . . surface SS a Locality. Place of observation. tempera- ; above + ture of sea-level. surface. Feet. Fahr. 142. Chiswick, Middlesex.....| Artesian well ........ 25) 49 6° % eeeceeveeeece ceee ” ” ec ee ee 39 ee 99 eeeeeeeeeeee ee 59 bbs eeeeoeeev#e 3” ee 143, Swinderby, Lincoln ....| Bore-hole............ 120? 48 °5 ? 5} ) 99 eoeee bb) eeeseoeeeeeseeee eae 39 99 a9 39 39 99 ”” OY a? ? ” ” oe ” oeee 9 39 9 ei, ” C oy) +P) ” ere yie ” e 33 144, Sperenberg, Berlin = siete oes ? m 48° 3* ” ” has oe : ” ” 3) 9) bP) 9) 99 39 bP] 2) +4 LE 9 3) ” 9 2) ane ® oP) 29 ” 2? i 2) om 2 ” 39 99 eee +B) eosee@eeeeeee ee bb) 39 99 eeee 3° eeeete e ”) 1444. St. Petersburgh .......| Artesian well ........ ap 39°17 145. Anzin, Nord, France....| No.1 Colliery shaft... os 50°5 ” ” eeeeeeeee#e ” = 9 eee ee ” 146. oD) 99 ceeoeeevteoeee No. 2t ” ” eee ee 99 vs Ree Nc Lateee iets ec eteie s Pipers 5 ue i 145. bb) 9 eoeeeeeeeee No. 3 99 3” eee ee 33 ” 99 ee e e +») ” eee ee 3” 148. 5B) +B) eeeeoe34ee*eeee No. 4, 9 9 eee ee 99 99 bB) e eeeveoe3s#ee#8e 39 5} e . ee ee 149. Schemnitz, Hungary ....| Elizabeth silver mine. } f from gh rom ys 5 ....| Maximilian ,, "al 1633 47 to ., ~ -...| Amelia i SF - 42 id RS Nee Stefan 6 ; i 9504 (mean ” ” eoee Siglisberg ” . 44 “3) 150. Boldon, Newcastle ......| Coal pit ..........0.. 97 47°18 »” ” eeeeee bb) ” eoeeesee4eeeeeete ” ” 151. Manegaon, India........| Bore-hole .........45- 1400 75 ? ” Sho) @eeeese#ee#e ” eeeeteeeeenstereee ” ” ” ” ” eeeseeseeeeeeeee 3” 39 ” ” ee eceeeee 9 se@ ee eee , 33 152. Pontypridd, South Wales.| Coal pit|| ............ 554 49? * This is the mean temperature of Berlin. + The depths here given are in Rhenish feet, 4052 Rhenish = 4172 English feet. t In this shaft there was a seam of decomposing coal at a depth of 90 metres. § Temperature of South Shields. : On Underground Temperatures. Table I. 79 ~ Vv Ve VII a Depths | Tempera- below ture at REFERENCES AND REMARKS. surface. depths. : | Feet. Fahr. ne t 142 65 56°2° | | Brit. Assoc. Report of 1875. Water stands 60 feet t. 206 55 from surface. 5 feet shaft down to 200 feet, ia 395 58 then a bore-hole. ij 145 100 68 9) 500 684 1000 6923 Brit. Assoc. Reports of 1875-6. Springs at 790 93 p pring ? 13800 yok +| and 950 feet. Strong convection currents affect Se 1500 73 results. = 1950 78 | , 2000 79 SJ | ie 144 100+ Berk.) } 700 70°8 if 1100 79°5 Brit. Assoc. Report of 1876. Diameter of bore at »: 1500 84.°5 ' 3390 feet, 12 inches ; then reduced to 6 inches. 4 1700 Sym | Bore-hole plugged to protect against convection it 2100 96 °3 | currents, and observations corrected for pressure. w 3390 115 °5 4 4.052 sf - 1442 656 54 Water overflows. i 145 126 56% ij ' 3 —s«-446 Bee a: | Obs. made in holes 0°6 to 0°7 m. deep in sides 4 607 2 Dies of shaft during sinking. Little circulation of ig 2 . air; 4 hour elapsed between boring hole and % 144 286 56 | inserting thermometer. Temp. of air in the ie 472 625 wet shafts, 1, 2, and 3 was from 52 to 54°: in m was 69 ae | the dry shaft, No. 4, 59°. . 4 . 442 Big ue? meee Brit. Assoc. Report of 1877. The actual tempera- 935 $ tures are not given; only the rate of increase 715 he which averages for the 5 mines 75} ft. for each 1358 1° Fahr. s Still air in gallery 783°. Trial holes 10 ft. deep ; oe oP 75 left four weeks to cool, temp. falling from 81 to 1514 7 P g 7 79°. Air travelled 3 miles and nearly stagnant. 151 10 81 . 60 81 The bore-hole had been 20 months at rest. 150 S27 Water stands to near top of tube. 310 84°7 152 855 62)°7 Report of 1878. Hole in coal 4 ft. deep. || The air current down the shaft amounted to between 20,000 to 30,000 cubic feet per minute. Neither the temperature of the air in gallery, nor the distance from the shaft are given. In the other parts of the mine, the air currents showed differences of 2 to 3°, according to the season of the year. 80 I Locality. 153. Bootle, Liverpool........ ” 399 ee eeeeoe by) 99 eetcesese 154. St. Gothard Tunnel ..... 99 99 99 3) eee@e 99 3) 99 33 155. Bristol, Kingswood...... 39 39 - 0 3) 39 2 156. 99 99 e e ” ” so 158. E59. Dulkkinfieldsp se..c cis ec wee 9) 9) 160. Talargoch, Flintshire.... 161. Manchester, Ashton Moss 162. Cheshire, Bredbury...... Nook Pit ...... a) 163. Radstock, Somerset, Wells May Pit 164. 59 Ludlow Pit.... 9 99 165. Southampton Common .. 1652. Ballarat, Australia...... 166. Pitzbuhl, Magdeburg.... 164. Artern, Thuringia ...... Prof. J. Prestwich. II Place of observation. Part shaft part bore-hole 99 59 eeeeeeeoe Tunnel® (oan enone Deep pit colliery...... 3) 9 Speedwell colliery..... ” 5B) ° » 34653530 c0 sorink oats Weve tel aves sane 33 e gg. a) ware eile) ele eece Coal pit 39 Be tee etiabetie ch-atet anole 99 = Lead mine, 2nd pit.... Coal pit ..... iravoWerekele 95 ee » e ” ae 59 eeee3eweeeertkees: 35 @eeeeeoerereeeve 99 @eeeseevoeneveee 08 Artesian well ......3. Copper mine........ Artesian well ?...csees ” 99 eeeeeeere IIL IV Height of san surface pers above = ee sea-level. ie. surface. Feet. Fahr. 40? 49 “6° ” 3%” ”” 33 Sur temp. of crest. 216 m 50 39 +” bb) >b) 216? e bb) bb) 190 49°5 bP) 3° ‘ 49 ” bP) +3 33 48 ” 190 49 48? 48 °6 ” 50 ee ” a ” 140 a 48°5? 47 °5? * The temperature of the springs in the tunnel was found to be higher than that of the rock. + These additional observations by Mr. Garside were made in the coal eams in On Underground Temperatures. Table I. Vy Depths below surface. Feet. 226 1004 1302 3100 4101 4615 4965 4108 44. 1367 1769 1232 1439 1769 465 555 636 660 1041 1987 2407 2416 2700 660 2790 1020 1050 560 810 1000 1210 760 VE Tempera- ture at depths. \ a I ES el Vil REFERENCES AND REMARKS. Bore-hole at top 24 in. in diameter. No correc- tion for convection currents. at depths-of 318, 800, and 1303 ft. | Reports of 1878-9. Swiss end of tunnel. Italian end of tunnel. “ Brit. Assoc. Report,” 1879. Ventilation slight, and care’ taken to avoid air- currents. Trial holes 2 ft. deep, plugged, and thermometer left twelve hours. Report of 1880.—Obs., distant from shaft 570 ft. Holes 2 feet deep. ” ” ” 321 ,, ” ” » 2022 ,, ” ” ” 360 ” ” »” ” 570 ,, Distance from air shaft, 1380 ft. ; air 714°. »” ” ” ESOOV ia hoa: ” ” ” SOOT 3 os 79. » ” ” SOO as) i> 753. Report of 1881. 1200 ft. from shaft. Air still. Hole 33 ft. deep. The temperature of air in the galleries in these and preceding pit are not given. In holes 2 ft. deep. Distance from shaft and temp. of galleries not given. A moderate cur- rent of air was passing. “ Brit. Assoc. Report,’ 1883. Holes 3 ft. deep filled with water. De Lapparent’s, “‘ Géologie,” 1881, p. 372. Ibid. The rate of increase only given. 81 Springs met with . holes 4 feet deep, and thermometer left 48 hours. The pit was entirely free from water. I The gallery was free from any strong air-current and the ground newly opened. YOL. XLI. G 82 16 8. 169. 170. Prof. J. Prestwich. Locality. Buda-Pesth, Hungary .. OMG Se s45ce5 a0 3405 Chili, Chafarcillo ...... W431. Brazil, Minas Giraés .... 132. 132’. 143. 174. 145. 136. 19%. 148. 179. 180. 181. 182. 183. 184. 185. 186. 18%. 188. Sark and Herm, Channel Islands Sheboyan, Wisconsin}... Ireland, various mines .. Cornwall, mean of ten mines. Ireland, Wicklow ....... 5, WMatertord..'.... » County Cork... .. Venice, Villa Grande. Venice, Gasworks....... Francisco Brussels, Belgium ...... Aerschot, Minden, Prussia ........ Arcachon, Gironde...... Pondicherry, East India . Dundee. sicee hee Seay 4 Bradford, Yorkshire.... . Black bpri swede rire Birmingham private well. II Place of observation. Artesian well Artesian well Silver mine TTON BUNCE Ve e's dic pinecone Artesian well .esesens Metalliferous mine.... bP) Ordinary well bb) eeoeceeeee Abandoned coal shaft.. Ordinary well eeeoeatesn Iil Height of surface above sea-level. Feet. 600 620 100—300 * An infiltration of water from a higher level was suspected. + Flowing water was obtained at 1340 feet in the upper portion of a Silurian sandstone. Water rose 104 feet above the surface. Discharge of water = 225 gallons per minute. IV Mean annual tempera- ture of surface. Fahr. a 50°5° 168 169 1470 191 142 132’ 193 134 145 176 137 178 1439 180 181 182 183 184 185 186 184 188 On Underground Temperatures. Table I. 83 Vv VI VII Depths | Tempera- . below ture at REFERENCES AND REMARKS. surface. depths. ——— Feet. Fahr. 190 598), | 216 64.°4 ee ae ny Communicated (1882) by Professor Judd, from 1640 ae letter of Professor Szabo. The observations were 1948 125 made in 1877 and 1878. There are hot springs 29917 ie r and trachytic rocks in the neighbourhood. The 9487 S high temperatures are dependent upon neigh- 2900 ae bouring old volcanic centres of activity. 2966 178 3183 TGs tou, 751 55* Schott in “Smithsonian Inst. Report,” p. 249, 1874. 930 69 *2 318 67°9 Henwood, ‘“‘ Trans. Roy. Soc. Cornwall,” vol. viii, uns ae p. 751 (1871). 1475 59 °1 Chamberlin, “Geology of Wisconsin,” vol. ii, 349 ee p. 165 (1873- a4): 672 68:8 | 552 55°5 The observations were made in sumps or springs. 672 57°5 840 Gun] 118 58 ; Laurent, “Revue de Géologie,”’ vol. xi, p. 258 (187 5). 236 62°5 215 54 Vincent and Rutot, “Ann. Soc. Géol. Belg.,” 453 5772 \ vol. v, p. 77 and 99 (1878). 2230 90 °9 413 ore \ Raulin’s “ Géologie,” 1879, p. 84. 261 O37 Medlicott, ‘ Geol. Survey of India,” 1881. 238 50 geo 54°5 alt Sixth Report of Rivers’ Pollution Commission, 210 49°5 1868. “Temperature of Wells.” 300 50 J t The water rose 5 métres abcve surface. § See temperature of Boehum, p. 60. || The temperature of Stonyhurst is 47: 9°, S4 Prof. J. Prestwich. I ee. SEE IV eight of i tae Locality. Place of observation. prin tempera- sea-level. ee surface. Feet. Fahr. 188’. Birmingham Waterworks.| Ordinary well ........ 350 m 48°7° 189. Kidderminster ......... “ oo as eee 320 4G ? 1990. St. Helen’s Waterworks . a 5y Ls a ee 100 ? 49 191. Tranmere, Cheshire..... By eH ES +5 49 -4* 192. Wallasey, SA ee eee s seit dale eee te 35 AOS. Worksop... ec ae ees 33 5p | eel wieheim eae 127 m 48°7 194. Scarborough ........... 5 ee A 176 m 47-8 195.~Hastbourne ..... da. enc. Artesian well .....2.0- 25 m 50 °9 196. Deal Waterworks ......| Ordinary well ........ 20 50 BOs. Dover soaptles.s Scmisie aie “5 55° pais eis See 380 m 50°3 198. Dover Waterworks...... o sa ttis =k DOES 40? ies 199. Grimsby Docks ........ > 55 wubareraee 10 48 200. Deptford Waterworks... 4 igo ee cee Ze | s 50°3 201. Sittingbourne.......... 33 Set tee ee ae 50 49°35? 202. Braintree........ deus ca)| Artesian awell eee. ae 220 49-5? 203. Wimbledon: :i.2<26 «<< s 551’ o/0 eho alee 170 49-6 204. Carisbrooke Castle, I.of W.| Ordinary well ........ a 50 ? 20%. Colchester «22 5,0000.02 45 Artesian well ......0. 109 m 49-4 206. Trowbridge Waterworks | Ordinary well ........ 140 49°5? 20%. Ostendy....... See oe Artesian well ........ 10? m 50 te rd ee é 208. Bourbourg,f near Dunkirk s. sy nad Wars Bogeioesle da 50 °2 209. Dunkitk’.3...:4.23 soe ys ale 2-2 a ae m d0°2 210. Newport, Isle of Wight.. igen ares 60 50 °9(a) ZES, Gosport...22--6 =e 6) ¥ pt Nae bee gee 20 m d0°6 212. Bothwell,§ Ontario...... - ok si eae BS cha a 45? 213. Croix, Dept. du Nord.... + aa eee aa 50 ? 214. Mons, Grameries Colliery.| Coal pit ............ 344 50°5 i as Te ee ds Bs, Siw Beata, Seen 3 is a x alerts tae sr, |, | resem ie Reena es ep as i, MAM pee orion 55 : u at * 49°4 is the temperature of Chester. + The water issued at the surface with a temperature of 18° C., wy rose 8 métres above sea-level at the first depth, and 11 métres at the last depth. + The well was carried at a depth of 250 métres into the chalk. § The water rose above surface at rate of 700 gallons per hour, from the Cor- niferous limestone. On Underground Temperatures. Table I. 85 J ie 5 40 VI VII | ae Depths. | Tempera- # below ture at REFERENCES AND REMARKS. surface. depths. | Feet. Fahr. Iss’ 400 53°60° | iIs9 160 54 190 270 50 | 191 | 428 | | isz| = 246 g1°8 = 1938 214 51°8 | 194 214 195 100 £0 ah vad af Sixth Report of Rivers’ Pollution Commission, : 19% 367 sy ars 1868. “ Temperature of Wells.” (I am respon- 198 220 52 sible for the description of wells.—J. P. 199 300 52°56 _ 200 250 54 | _ 201| 400 53 202 430 | «4 203 200 54°3 + 204 240 Louis | 205 400 52°6 206 200 bee) 207 567 Bari a 617 i ; Letter from Prof. Dewalque ; February, 1883. t 981 516 | | 20s 54d. : 209 426 } Letters from Prof. Gosselet, February, 1883.. 210 467 62 Letter from Mr. H. Turner, September, 1883. +211 372 ts I (a) The temperature of Osborne. «212 475 54 | Sterry Hunt, ‘ Chem. and Geol. Essays,” p. 159. ' 213 271 iy Letter from M. Ortlieb, Feb., 1883. Average of 7-wells. —— noe oa Letter from M. F. L. Cornet, April, 1883. 1141 ve A great aoe of water flowed from the rocks || These wells pass through Tertiary strata and end in Carboniferous limestone. ‘ The water in all of them rises above the surface; one well delivers 12,000 litres | per hour. {| Thermometer placed for not less than an hour in holes, 1 métre deep, excavated . in side of gallery. 86 Prof. J. Prestwich. I II III IV Heipht of | “team ; : surface vate Locality. Place of observation. tempera- above ture of sea-level. surface. Feet. Fahr. 215. Mons, LaLouviére Colliery} Coal pit .........++. 410 . 50D 39 99 e@eeeoev 399 eeeeeoeeeeeeeese 3” by) 5 55 : . another pit.. 351 5 9 +) eeeeee 3” eeeeovaeeesee? bb) 3) 216. Mons, Cuesmes Colliery .. aN ERG Fy 213 Ps bb) 9 ee pute: ne, seers be us ke +) ee e ee 33 99 ” Damme egereweue)iszs op ee ” 9 9 ” oy) eecereceavtrteoce 99 or) 99 3” eeeeoeeee 99 ee 33 ee 99 99 @eocsveeee goo) Si eher eke! exe felene, eee 197 ee 219. North Seaton, Newcastlet Bad yt ae diag. s eee — 40 475 218. Ashton Moss Oolliery, ¥5 IG ete Waa Si 48 Manchester 220. Dolcoath, Cornwall .....| Tin mine ..... oe traniee 280 50 ” ” eecene 99 eceocee ry e¢ ” 99 SL ieieleiione ” oe ° +B) 99:4.-7 | aera eee, 99 e ee 39 by) 9, Te ONS ere neler el ehae ene) e e 9 913) 27. ee ree a Reire: 99 e 9 ? eee 992 1 eeler ais) «Seiki ele! wit ee es 221, Passy,{ Paris ..........| Artesian well......... 158 51 223. La Fayette, Indiana .... oO eee ee i bie 224. Buenos Ayres .......0¢- i WG oes oe 62°7 226. Croft, Whitehaven§ ....| Coal pit ............. 72 48 °5 22%. ” ” eeoeee 99 PHO RO oe Co ee ee ee ” 228. Lye Cross, Dudley|| .... 53 one Sie eee Coe 822 47 5 229. Denton,§ Manchester ... 55. | Selnala oreo eee ee ‘ia 48 230. Richmond,** Surrey ....| Artesian well......... Se 49-6 231. 9 ” eee ee £3) or) eeeeeuee eee ee 33 * In another trial made 300 métres from the shaft, the temperature at the same depth was found to be 70°75° F. t+ These observations were made by Professor Lebour at a point under the sea, half a mile beyond water-mark, and 660 feet below O.D. { Diameter of well at top, 4 feet. The observations recorded in the preceding list (Table I) are grouped in the following Tables II, III, IV, according to class, geo- logical structure, and geographical position :— a PPE NTRP On Underground Temperatures. Table I. 87 ¥ VI VII Depths | Tempera- below ture at REFERENCES AND REMARKS. surface. depths. Feet. Fahr. = ° Letter from M. Cornet, April, 1883. Observa- ais ik Ns tions made 1200 métres from the shaft in galleries; perfectly dry and not ventilated. 787 69* Ibid. In dry gallery 100 métres from shaft. 1361 81 Ibid. Ina new shaft without water. 216 1548 79°5 Ibid. At 2180 métres from shaft. ) ie 49°7 », 2400 Ag Pe | In galleries - Fills », 2600 pe a rdry and not 1680 82 ee 400 a4 fe | ventilated. Gee thes acd 46! f salt wat er. placed in a spring of salt water issuing 1709 85 { from a bed of sandstone. 217 620 61 ‘“* Brit. Assoc. Report,” 1883. P 218 2880 84 Ther. left 48 hours in hole. 220 252 7 390 65 | awe Dy (a “Brit. Assoc. Report,” 1883. 1884 ee , r (a) Observations considered defective. 2124 83 2244, 90 J 221 1924 82°5 Letter from MM. Mauget and Lippmann, Jan. 1872. 223 213 55 ** Rev. Géol.,’’ vol. i, p. 9. 224 255 69°8 “Quart. Journ. Geol. Soc.,” vol. xix, p. 69. 226 1140 \ | 73 | 22 125 : * te r| “ Brit. Assoc. Report for 1882.” 8 Biase | 229 1370 Ebina 230 1176 7° i Professor Judd in “Quart. Journ. Geol. Soc.,” 231 1337 46 “5 vol. xl, Pp. 724, (1884). § Hole 4 feet deep, bored upwards in roof of coal. The stations in this pit were under the sea. || Hole 4 feet deep in shaly floor, under the “10 yards”? coal. §| Situated in the valley near Dukinfield. ** Slight overflow, 4 or 5 gallons per minute. 1st. Coal Mines. 2nd. Mines other than coal. ord. Artesian Wells and Bore-holes. 88 Prof. J. Prestwich. Column 1 of these tables gives the original number of the obser- vation in the general list of Table I. Instead of the columns for the height and temperature of the surface, given in Table I, another giving the thermometric gradient, are substituted in the following tables. For subjects peculiar to the separate tables, special columns are introduced in each case. The gradients for the total depths are given in stronger type than the others. 7 Column VIII in Tables II and III gives the temperature of the air in the gallery in which the rock or spring temperatures are taken. TasLe II.—COAL In this table there is no separate column for the strata, as they all In the few instances where they are overlaid by newer strata, the par- Column IV gives the distance in yards of the place of observation the face of the coal. It is, however, not often recorded. Columns V and VI give the depth of the hole drilled for the ther- In Column VII, the numbers in brackets show the difference of while the rate of increase between these depths is given also in italics in depth. I Tie Til IV Number in __ | Distance of the general - Name of colliery and place. et ae rie oy een blo a or shatt. o servation | a from shaft. Feet. Yards. England. 14 Whitehaven Collieny* 2 cai... 0% + <0 «> « 480 15 Workimptow Colliery, cinisctsct oe vie eee 504 16 Northumberland, Percy Main........... 900 193 bg Killingworth .......... 1200 150 Nieweastle, i oldotine wiariss icy > ain. ss easier 1865 : MRT me BAR Se 1/k are 1514 9 We ik faleaststeiste nies oats wshd je nul elo U ae ner 214 $5 NorGhwSe2bOMwit 2) om a icie sinrsuners 620 30 Sunderland, Monkwearmouth........... 1584 116 Durham, Biettoniitgwns vince ce ees) were ee 1100 312 er Te sent 1135 1935 +P) 9 On Underground Temperatures. Table LI. 89 Those observations in which there are readily-apparent errors, or which are repeated more correctly at later dates, are not brought forward from Table I. Nor has it been considered necessary to repeat the fuller particulars there recorded, nor other observations, except such as bear upon the rate of increase of temperature with depth. The numbers in the first column will readily enable the reader to refer back to these details in the first general list. The thermometric gradient is in all cases calculated upon the mean surface temperatures, and allowing for height above the sea- level. PITS AND SHAFTS. consist of the usual shales, sandstones, and coals of the Coal-measures. ticulars are given in Column II or in the notes. from the shaft, showing the distance the air has to travel before reaching _ mometer, and whether placed in the coal, rock, or water. temperature between the two depths given in ?ttalics in Column III, Column IX ; the figures in thicker type refer to the gradient of the entire V VI VIL “VEE 1.6 xe Position and = , : : h emperature a ae depth Bate of : increase of Notes and remarks. depth in feet Coal (C). of coal, |p ain in| . tor each Rock (R). | Depth.} rock or ae degree Fahr. Water (W). water, | 5° °'Y- Feet. Fahr. Fahr. Feet. 14 W we 60° Fens 42 * At Whitehaven and Work- ington the Coal-measures are ial in 60 mg a unconformably overlaid by 200 2G. ,; a 68 70° 46 to 300 feet of Red Sandstones 12 74, oy ay and Marls. ” ve 150 R 10 75 LD 49 = - 79 78°5 47 a ce (4:0) Be 37 219 ee ee 61 ee 45 30 R os 72°6 es 62 116 =C 3 60 50 85 9 9 68 69 5d 90 Number in the general list, Table I. 116 136 a 4 | ill 126 104 122 139 Prof. J. Prestwich. II Name of colliery and place. England—continued. Durham) Wletton Wg. <2)... se ic see eine +) +B) peoeeoeveeveevedseeveeo ee eo ee 2) 99 e eee e@eeeveere7ee e200 o © Sa wouth Hethome 4... sec neti bP) 99 POCO CLC CO Fe Oe Ce ee CP) 9 99 ” e ee bP) 99 eovevees on eevee Lancashire, Worthington....... Seinretanl ae Wagan, Norley Coal (Co. ..). tia. «ee oe oe b>) 93 eseeoeeeee*eseeeeee eee Manchester, Pendletont (340 feet of Trias- sic and Permian strata overlie the Coal- MACASUILES) (ie iele ioe ateleee crometett ito eleters 32 2) 39 ON bP 93 9} IO 99 39 39 Keo Dukinfield, Astley’s|| (708 feet of New Red Sandstone overlie the Coal-measures) 9) 9) 39 ONO III Depth of pit or shaft. Feet. 1270 1315 1360 1395 1400 1060 99 1166-1786 1466—1736 1803 1487 600 1674 2445 1674— 2087 2037—2445 1674—2445 1944. 2214 1944—2214 2088 99 1987 2416 IV Distance of station of observation from shaft. On Underground Temperatures. v VI VII Position and VIII IX Temperature at depth of hole Ratcvon for thermometer. depth pe on depth in feet Coal (C). of coal, | oe air i for eaeh Rock (R). | Depth. | rock, or fle m| degree Fahr. Water (W.) water, | 82 CTY: Feet. Fahr. Fahr. Feet. 16 C 3 63° 58 5° 79 ” ” 69°5 68 59 ” PP 66 62 72 2) 99 71 73 58 33 399 70 5) 72 60 136 R 100a 66 a 60 ” 400 72 ie 59 ” 670 77 a 58 9 oo (11 “L) 6.0 a2 39 ee (7 27h) a 52 121 W we 82 62? 53 1 OR 4 80 70 46 = eo 66 ee ee 126 R 3 78 if 56 2? ” 94 ee 53 : (9 0) fe 40 fe ee (7 ‘0) eo 58 as (16 :0) : 58 104 RS§ | 3to4 17 64 68 bP) 99 86 67 a9 BiG aa (9:0) co 30 122 R 3 78 65 70 ” » 82 71? 63 1539 _,, 4, 74, Wil OS) 74: ” ” 81 79°0 73 Table I. 91 Notes and remarks. * The temperature observa- tions in this pit were made in a bore-hole (a) drilled at the bottom of the shaft, which is 1066 feet deep. The first series of observations were made by Mr. Atkinson in April, 1869 (Coal Commission Report, vol. ui, pp. 128 and 133), after the boring opera- tions had only ceased twenty minutes. The temperature at the bottom of the bore-hole, then 858 feet deep, or 1924 below the surface, was 96°. The experiments were re- peated after the boring opera- tions had been suspended about a week, and the tem- perature found to be the same as before. But those made three years later (April, 1872), and recorded in the British Association Reports, show a considerable decrease of tem- perature. The abandoned bore-hole had then silted up to the depth of 644 feet. The encased thermometer was pushed down to 26 feet in this, or to a depth of 1736 feet from surface, where the temperature was found to be Tia". + The observations were made in hoies at bottom of shaft during sinking. t The distances in Column IV are from the down-brow. § The temperature of the rocks in this pit was from 2° to 4° higher than that of the coals. || The first series of observa- tions at Dukinfield, although taken with great care, are wanting in details. We neither know the tempera- 92 Number in the general list, Table I. 1539 112 Lis 2s 7 Prof. J. Prestwich. ft Name of colliery and place. England—continued. Dukinfield, Astley’s (708 feet of New Red Sandstone overlie the Coal-measures) 2) > 99 Manchester, Ashton Moss (1881) ........ Ashton gloss mUGSe) ace ec seins) eine hie ese Cheshire, Bredbury ...... Sedooyas 53 INGOMGR bs ck seine es Sn Riccio Sates Barnsley, Sharleton Pit ..........ss--:. Wakefield, Victoria Pit . aelesetelel Nottinghamshire, Hucknall 1 Dorkardt . 4, Annesleyt 55 Kiveton Parkt Swanwick§ ....::.... y Moiral| Bristol, Kingswood Pit... 2......%%.. bh Ge CR tt ec . ieiscub etmietene ape «satel Denton, Manchester. .\.cis%ic 0 cess «=o 2 «510 Bristol, Speedwell] .. coc... tate ve ws om 0 + e@eeeoeeover e 9 ” eeeecVaeevce gpeoe ee ee ee ee Bath, Radstock, Wells May Pit** Tiudlow Pit ....sscn%.s- ) ” 3) 3) bP) eeeesn 99 e@eees e@eeee eeeoene New Tredegart}..... Til IV Distance of Depth of pit | station of or shaft. observation from shaft. Feet. 2'700* 1987—2700 ve 2790 ny 2880 1020 1050 1005 1455 1250 sic 1425 1200 966 1030 441 45 1367 ee 1767 “s 1867 —1767 oe 1317 ve 1232 oe 1439 ee 1252—1439 560 ee 810 1000 1002 1503 1605 1770 1002—1770 360tt 1210 1400 1690 1210—1690 _ On Underground Temperatures. | Vie vin” YET 1x Bien and depth of hole eat at Rate of |_fer thermometer. for thermometer. dept Baars ars, oh depth in feet | Coal (C). of coal, for each Rock (R). | Depth. | rock, or ot ah im degree Fahr. | Water (W). water. Sea Feet. | Fahr. Fahr. Feet. is9 R 4 865°: | .707oe 70 ee es (12 cenye ee 51 161 R 35 85 °3 a 74 21s _,, $5 84 ) Bb) 3 ee 67 110 _—,, 3 60 58° Si. o 7 70°5 58° 70 ¥ a 73 71 68 ” ’ 78 ” 61 we : (13) es 59 112 C,R i 61 62 30 C ¥5 65 65 58 C,R ae 68 66 60 ze FP 75 74 54 ee ee (8) ee 60 131 OC J 58 60 80 - 3 63 70 61 % % 67 72 80 ” ) 69 an 74, Table II. 93 Notes and remarks. ture of the air in the shaft nor the depth and position of the holes. Nevertheless, the later observations here given show also low temperatures. Mr. Dickinson, however, calls attention to the fact that before the shaft was sunk two of the principal seams of coal in the upper part had been worked away from the out- crop down towards the Astley shaft, and in one case a tunnel had been driven to where the shaft had come. * This pit has now (1884) been carried to the great depth of 3150 feet. + These were all new pits. {£ Hole at bottom of shaft. § Very wet pit. || An old pit. {| The strata dip about 1 in 6. ** Dip small. The Coal- measures in this district are covered unconformably by 100 to 200 feet of Jurassic and Triassic strata. tt The dip is small in these Aberdare pits. {t£ The depths in these pits are not the depths of the shaft, but are, in each pit, taken on one and the same level, and the depths given are those beneath the surface, the differences of depth being caused by the coal seam passing from the valley in which the shaft is situated under an adjacent hill. oe Number in the general list, Table I. 113’ 114 Lis 1532 22 226 229 228 140 141 214 215 216 145 24 25 23 Name of Prof. J. Prestwich. II IBUL . Depth of pit colliery and place. a eer England—-continued. Bees: South Wales, Aberdare, Vochriw Dowlais*. 11038 ” ” ” . 1320 39 bb) 99 628 », Dowlais (ironstone). 371 ” y) ” 5 536 ss 3 Cwmbach (nace: 230 93 99 99 988 ‘ Bomby ard cli: e-jeoielenetete ere 855 >} ) Neath eeeaeceveeveaeeeseeee eevee 540 Croft, Whitehaven .......... Sie Sa S06 1140 99 99 eeeaeveaeeeeeesee#eteeee ee 1250 dive Cross, Wudley -ntetcte. «1-12 e)c (intel t= 700 — Belgium. Liége,t Seraing Collieries .........see0- 761 939 eeeeoveeoeeeeveeee eee 1017 99 eeeeeoeeoeeeeeee 1656 ath Be aE Magee US ei Meee 761—1656 . dies ee E sc eeveee 1017 —1656 Mons,§ Grameries Colliery...........20. 679 be) bb) eeeeo0aeseeeese e@ @eeeeoeeee 1013 : La Louviére Colliery........... 1194 of GEER ain ae - 1456 e Ce ion ee ree 8: 1194—1456 - 4 a new shaft ........ 1361 Hf Cuesmes Colliery........ estate 1548 re) ” : 1680 i Aoi. AA OREN TIS 53 1548—1680 France. Anzin,|| Valenciennes ee 126 3 eth No. sie 658 126—658 Dittry, Calvados) Wiens: %is2 +020 0s » aisle 325 Deeise, Nieware tere mtetes leis cln/e =i Gielete) esas 561 Carmeaux,tf Tarn ....... Sis ie’ Ore terol MaMa 630 1V Distance of | station of observation | from shaft. 197 69 V On Underground Temperatures. Position and depth of hole for thermometer. Coal (C). Rock (R). Water (W). 13’ C bP] 29 14 R bP) mus C 99 152 ,, 22 R 226 _,, 227 228 ,, 140 R 3) 141 ,, 214 R 9) 215 _,, 99 R 216 ,, 2? 145 R bP) 24 C 23 ,, 23 4, VI Vil VIII IX T t t en ane increase of depth in feet of coal, Reon for each Depth. | rock, or 1 degree Fahr. water. | 8° CTY- | Feet. Fahr. Fahr. Feet. A 60° 59° 80 A 62 BS 83 Ae 61 65 42 “5 56 55 61 Be 59 58 45 x 55 48 36 * 61 63 78 iy 62°7 a 62 2; 42 é 45 4, (83 ate 47 ” 5B) OO 51 ”9 57 5) ee 70 16 77. 78 30 S5 78 77 40 r 87 VT D 46 ae (10) le 90 oh (9) sie 70 34 66 is 45 93 69 ae 56 a 76 ar 48 3 81 ae, 49 (5) av 62 ot 81 oe 45 “A 79°7 ae 53 i 82 Ae 54 ae (2 °2) ae 58 2 56°5 a 21 5 67°7 54 39 : de (11° 2) 47 2 61 70 386 be 72, vie 33 és 67 74.3 53 Table IT. 95 x Notes and remarks. * In this pit the working proceeds from a hill towards a valley. + These are the distances of the stations under the sea. The sea there being about 12 fathoms deep. Taking the temperature of the sea at 48°, or deducting 72 feet, Professor Everett makes the thermo- metric gradients 45° and 47°, which is probably the more correct. { The dip of the coal in these pits is considerable. In the “ Brit. Assoc. Reports,” the temperature of the ground at a depth of 5 métres, is esti- mated at 54° F. The gradient here given is, however, cal- culated on a mean surface temp. of 51°. § The dip here is also con- siderable, and the Coal-mea- sures are overlaid by a thick mass (300 to 400 feet) of water-bearing Lower Cre- taceous strata. || Observations were made during sinking, in holes in- serted horizontally in side of shaft. { Strata nearly horizontal —pit dry. ** The strata here dip 25° S.W., and overlie crystalline rocks. t+ A new and dry pit; slow ventilation. The water of a well immediately above this pit, 38 feet deep, had a temp. of 55°5° F. 96 Prof. J. Prestwich. I il Number in the general Name of colliery and place. Til Depth of pit list, Table I. ute Feet. North America. 59 Eastern Virginia,* Mills’s pit............ 4.20 6O os Wall's pitas cr eae 570 Gl hi Midlothian pit...... 780 A (Another account (@)) 600 Pe ss ee ne ott Resets 780 16Vi Distance of station of observation from shaft. Yards. Those observations which were made in Springs issuing from the in Wells or sumps, W, and those in holes drilled in the Rock, R. an afix is made of Ror L. The distance of the point of observation, The nature of the strata The Thermometric Gradient in Column [X refers to the entire refer to the gradients for the intermediate depths (also in italics in at the spot is known in very few instances. Taste III.—MINES depths that is given (in brackets) in Column VII. I II Number in general Name of mine and place. list, Table I. England. 24 Cornwall, Dolecoath Mine* ....,.. 53 % ‘ (1822) ri 9) 9 (1853) 44 9? 9) (1857) 220 a III Nature of rock. IV Depth. On Underground Temperatures. Table III. a Vv WEL WEE VIII. IX x Position and depth of} Temperature at hole for thermometer. depth _ Rate of increase of depth in feet Notes and remarks. Coal (C). of coal, Pate i for each : Rock (R). | Depth. | rock, or | ° Heat degree Fahr. | © Water OW), water. | 8° °tY: . Feet. | Fahr. | Fahr. Feet. is * Temperature of water eee. | 68 “ 7 collected at bottom of pit. 60, - fa 65°5 se 65 Prof. Lebour’s later statement ; relating to Virginian coal-pits or 3 8 | e8 ae i. (a) seems more reliable. ? | ? © 55 || OTHER THAN COAL. ; rock or lode, are marked S, in Column V; those in water collected Accordingly as the springs (S) are known to issue from rock or lode or station, from the shaft and the temperature of the air in the gallery in the following tables is given in Column III. : depths given in Column IV; but where the figures are in ttalics they : Column IV). It is only the difference of temperature between those _ i ite i VL VAL Vill IX | OX ‘ Position of Temperature at | Rate 3 thermometer. depth of _ | Number _| increase i in of @ | general depth Notes and remarks. ¢ lisf, {Water (W).| Depth of | Of the | Of air for |) | Table I. Spring (S).| hole in | rock or in each ; Rock (R). rock. water. | gallery. | degree FE. Feet. Fahr. Fahr. Feet. | y 25 g is 82° 80° 45 * TheSlate in this mine } extends to depths of , 53 | RB 2 76 ad about 800 to 900 feet, ri ss 2 79°5 78 55 the deeper levels are in pe = Granite. This, the deep- 34 » vs 13 A is est of the Cornish mines, 220 ss “a 64 ave 18 has now (1884) reached L | a depth of 2400 feet. | VOL. XLI. Ji a | oe. ie 98 Number in general list, Table I. aor 499 49h 491 49j 49k 491 49m 49n 49a 49) 49c 49d Prof. J. Prestwich. II Name of mine and place. a a ee | England—continued. Cornwall, Doleoath Mine ........ resavean. wicca cis Huelivor sce Euel Damiselieve © a: Botallock AO, 30 000N. == O20 34,404 ,, = 773 Critical pornt. A000) wi) ==. 88a DO000 a 2 LOO? NCO 000 e2ila3 WSO OUO SHS If there are experimental errors, as I consider not improbable, such as would reduce the gradient to 45 feet per degree, the tem- perature at the depth of 150,000 feet would be 3383°, unless the increase of heat modifies the conductivity of the rocks at depths. Or if in centres of crystalline rocks and slates, as in Cornwall, and with a gradient of 40 feet, a temperature of 3000° might be reached at a depth of 120,000 feet or about 23 miles. * M. Delesse, in his paper on the water in the interior of the Earth, considered that notwithstanding that water tends to pass into vapour at the high temperature of great depths, the pressure of the overlying strata and the resistance they offer to its return being greater than its tension, would cause it to retain its liquid state. But at a depth which he estimates at about 60,000 feet, and at a temperature of about 1100° F., the overlying pressure (taken at the rock weight), and the elastic force of the vapour of water would be in equilibrium. ‘‘ Bull. Soc. Géol. de France,”’ 2nd Ser., vol. xix (1861), p. 64. 24 Prof. J. Prestwich. Besides these, there are other considerations which should not be overlooked, although it is impossible at present to assign a value to them. Still they may be placed to a suspense account. ‘The first is whether there may not be areas of certain rocks in which the gradient is more rapid than in other areas; and whether in tropical regions there is not generally a more rapid thermometric gradient. In the paper on Underground Temperatures, a few of the observations raise these questions, as questions for further inquiry. The second point, which I have already mooted,* is more purely hypothetical. It is whether the effect of the excessive cold of the glacial period—or cold prolonged during so many thousands of years —may not possibly have left its mark on that portion of the earth covered for so long a period by perpetual snow and ice,—whether the loss of heat in the upper layers of the crust may not only have altered the thermometric gradient, but also induced, as it were, premature contraction by an excessive abstraction of heat during that period. Whether also that outer portion of the crust so affected might not now present a slower gradient than the present mean surface tem- perature would warrant, while at greater depths a normal more rapid gradient may still prevail. And whether or not this might possibly be an element in the present effective rigidity of the crust ? Taking therefore into consideration all the conditions to which water becomes subject with increasing depth and the rapid increase of temperature, together with the circumstance that while the pres- sure of water increases with depth in simple arithmetical progression, that of the elastic vapour of water is one of a very rapid geometrical progression, it becomes extremely improbable that water can penetrate beyond a certain depth beneath the surface. Roughly, it is a ques- tion whether 7 to 8 miles would not be a limit. At all events I feelit— impossible to accept any hypothesis based upon an assumed percola- tion to unlimited depths, and am forced to look to other causes in explanation of the presence of water in volcanic eruptions. It is true that the experiments of Daubrée, which will be further alluded to, show that owing to the force of capillarity, water can pass through porous strata against a considerable resisting pressure, but on the other hand Wolft’s experiments show that the effects of capillarity decrease with the increase of temperature, and tend to prove that there is a point at which they would altogether cease. ‘It may also be a question whether at the high temperature at great depths, the vapour of water would not undergo decomposition, for M. H. St. Claire Deville} has shown that under certain conditions, at a temperature of from 1103° to 1300° C., it is dissociated into its * “ Phil. Trans.,”’ vol. 164, p. 305. + “ Sur le phénoméne de la dissociation de |’Kau,”’ “ Comptes rendus,”’ vol. lvi, p- 199. On the Agency of Water in Volcanic Eruptions. 125 elements, and in so dissociating it augments its volume by one half, and its pressure in proportion.* That water is decomposed in contact with lava during eruptions, is rendered probable by the observations of M. Fouqué during the last great eruption of Santorin, for he found that the gases given off under water during the eruption, and collected as they ascended through the sea, often contained as much as 30 per cent. of free hydrogen, and from the circumstance that he also found free oxygen occasionally present, he considered it likely that the vapour of water exists in a state of dissociation in the lava during eruptions.f : Other geologists have contended for the possibility of water gaining access to the volcanic foci by fissures opening into the sea-hed.t These fissures are supposed to be formed by the molten matter struggling to escape. To this it has been rightly objected, that in such a case the lava would at once fill the fissure to the exclusion of the water. By others it has been suggested that the fissures are caused by the escape of imprisoned elastic vapours ; but as Mr. Scrope remarks, this is reasoning in a circle, for while it supposes the aqueous vapour to be the cause of the disturbance, it yet proposes to introduce the water after the effects attributed to it had been pro- duced. The second objection is, that supposing it were possible for water to penetrate to the molten magma and to be converted into high pressure steam, would it be possible for it to force forward and gradually erupt a column of lava extending from the molten mass below to the volcanic summit? Bischof’s§ hypothesis was founded on an erroneous estimate of the elastic force of steam. Would not also, on the fissure hypothesis, the pent up elastic vapours, which are supposed to force the lava up the volcanic duct, necessarily take the line of least resistance, drive back the column of water in the fissure and escape with it? But the objection to which I attach most weight and importance is one which deals with facts which are within the scope of actual observation. On the hypothesis that attributes the extrusion of lava to “‘the expansive force of some elastic aeriform fluid, struggling to escape from the interior of a subterranean body of lava,” it would follow that no lava could escape without the accompaniment of the propelling aeriform fluid, nor could any large evolution of vapour or gases take place without a large eruption of lava, for the relative * At the same time it is to be observed, that enclosed in a platinum tube water does not decompose at a temperature near the fusing point of the platinum. + “ Santorin et ses Eruptions,” p. 232. t “ Bull. Géol. Soc. de France,” vol. xiii, p. 178; vol. xvi, p. 43; and 2nd Ser., vol. i, p. 23. § “ Edin. New Phil. Jour.,” vol. xxvi (1839), p. 132. 126 Prof. J. Prestwich. discharge of steam and lava could not fail to bear some proportion one to the other. Although the phenomena accompanying volcanic eruptions are so constantly recorded, those which bear in particular on this question are generally so mixed up with the other details, that it is not always possible to determine their relative bearing and sequence. There are, however, an ample number of cases to show that the dis- charge of lava is not in proportion to the discharge of steam, nor is the discharge of steam always in accordance with the escape of lava, which they should be if the hypothesis were correct. These con- ditions would seem on the contrary to be perfectly independent one of the other. It 1s of course conceivable that lava of an extreme fluidity and offering less resistance to the escape of the elastic vapours, might be ejected in lesser quantity than a more viscid lava, which presented more resistance, or that paroxysmal explosions may disperse the lava in aerial discharges, and reduce the importance of the quieter outflow ; _ but these occasional occurrences would not affect the more general results. There are too many great eruptions that have been attended with a small discharge of lava, and too many of the largest lava streams have been erupted quietly and with a very small exhibition of explosive violence, to allow of much doubt on the subject. Sometimes, when the discharge of lava has been at its maximum, the explosive violence has been at its minimum, and, on the other hand, violent detonations have been attended with small overflows of lava. According to Daubeny,* there is no recorded lava-flow accompanying the eruptions of Vesuvius prior to the eruption of A.p. 1036. This, however, may be the mere absence of record. Still, it would seem to point to the prevalence of paroxysmal eruptions like that of the great eruption of 79 B.c. Mr. Scrope divides volcanic outbreaks into periods of moderate activity and of paroxysmal violence,t and he himself remarks that ‘the volume of lava poured out by an eruption does not preserve any constant proportion to the force or continuance of its explosions.” He instances Htnat as an example of almost continual moderate activity with occasionally more or less paroxysmal outbursts. The voleano of the Island of Bourbon offers another example of the same kind. He further points out§ that “in all cases where lava is emitted its protrusion marks the crisis of the eruption, which usually attains the maximum of its violence a day or two after its commencement. The stoppage of the lava in the same manner indicates the termina- tion of the crisis, but not of the eruption, for the gaseous explosions * “ Description of Volcanos,’ znd Edit., 1848, p. 225. + ‘“ Volcanos,” 2nd Edit., p. 16—19. t Ibid., p. 24. § Op. cit., p. 23. On the Agency of Water in Volcanic Eruptions. fe continue often for some time with immense and scarcely diminished energy.” Vesuvius “has often continued in eruption for periods of several months, discharging moderate jets of scoriz, lapill, and sand, from temporary orifices at the summit or flank of the cone, or at the bottom of its crater, when there was a crater; while streams of lava welled out, sometimes almost with the tranquillity of a water-spring from the same or from contiguous openings.”’* . Professor Palmierit says of Vesuvius, that on some occasions the eruptions commence with explosions and detonations of greater or lesser violence, ending with a great eruption and a copious flow of lava; and that at other times great eruptions have taken place with- out any precursory signs. Professor Phillips observes of the great eruption of Vesuvius of 1794, which was characterised by the flow of some of the largest lava currents ever erupted from this mountain, that ‘‘for nearly a month after the eruption (of lava), vast quantities of fine white ashes mixed with volumes of steam were thrown out from the crater.’’t M. Ch. St. Claire Deville§ states that the great eruption of Vesu- vius in 1855 was one of the most tranquil. The projections only lasted a few days, and the detonations soon ceased. The lava continued to flow for twenty-eight days, and formed the largest current which has passed out in the north-west direction.|| This eruption was in great contrast with that of 1850, which was one of the most violent and par- oxysmal, when the mountain was changed in form, the central cone reduced, and the crater enlarged to 2 miles in circumference, yet the flow of lava was comparatively small. The eruption of Htna of 1852 was one of unusual magnitude, and the flow of lava greater than ever witnessed, except probably in 1669. It commenced in August with violent explosions and ejection of scorie. The lava then began to flow from several openings, and flooded the country for a length of 6 miles and a breadth, in places, of 2 miles. The ejections of scoriz continued during sixteen days, but after that time they almost ceased, except in a few smaller craters, though dense volumes of steam were occasionally discharged from the central crater, but the flow of lava continued with little interruption through September, October, November, and December, and did not entirely cease until May, 1853.4 An eruption, which seems of itself almost sufficient to prove the * Op. cit., p.17. The italics here and in the following pages of this chapter are mine.—J. P. + “ Eruption of Vesuvius of 1871-2.” Mallet’s Translation, pp. 94, 99-100. ft “ Vesuvius,” pp. 92-4. § “ Bull. Soc. Géol. de France,” 2nd Ser., vol. xii, p. 1065. || “* Vesuvius,” p. 107. {| Lyell, “ Phil. Trans.,” vol. 148, p. 18. 128 | Prof. J. Prestwich. | ane independence of the causes leading to the outflow of lava, and those generating the elastic vapours, is that of Santorin in 1866, recorded by M. Fouqué.* In the centre of the bay formed by the great encircling old crater-walls of the islands of Thera and Asprosini, stands the small island of Kaimeni, the product of later eruptions. On the 26th January, 1866, the loose blocks on the southern slope of this island began to move—on the 27th slight shocks were felt, gases evolved, and fissures rent in adjacent buildings. The ground in a small sandy bay was observed to rise, and by the 4th February the erupted mass consisting of blocks of lava, had attained a height of 32 feet. By the 5th, this protuberant mass of lava had increased to 230 feet in length by 98 feet in width, and 65 feet in height, and on the 7th to 492’x197’x98'. The adjacent water was hot and the surface of the lava was consolidated, though it was incandescent at night. Until the 12th February there were no detonations and no explosion, notwithstanding the large quantity of lava emitted, for it was not confined to the matter above water, but it was, in places, gradually filling up the bay itself; and where there previously had been soundings of 103 fathoms, the depth was now reduced to from 40 to 70 fathoms.+ M. Fouqué remarks,t that ‘‘at the beginning of the eruption the discharge of lava was the most salient phenomenon ; the rock-emission proceeded in silence ; it was only at the end of several days that the explosions and ejections commenced and a crater formed (the volcano of Giorgios).” The explosions attained great violence on the 20th and 22nd, and on the latter day the column of vapour and ashes rose to a height of about 7000 feet. In April and May lava flowed more freely. The eruption was prolonged to 1869, when the explosions were still frequent but the discharge of lava very small. Another eruption commenced in February 1867, in the sea-bed west of Kaimeni, and by the 17th an island (Aphroessa) was formed 328 feet long by 196 feet wide and 32 feet high; while the adjacent sea-bed was in places reduced from a depth of 296 fathoms to 108 fathoms. This also was effected quietly and without noise, and it was not until later that the explosions began. So noiseless and so steadily continuous was the protrusion of these masses of lava at first, that Dr. Cigalli, who watched them from day to day, compared their growth to the steady and uninterrupted growth of a soap bubble. Much of the lava of this great eruption was very compact, and not at all scoriaceous.§ * “ Santorin et ses Eruptions,” Paris, 1879. + Ibid., p. 36 et seq. ih LO Ve § Op. cit., p. 72. On the Agency of Water in Volcanic Eruptions. 129 But probably the eruption most remarkable for its magnitude, and at the same time for its quiet, was that of Mauna Loa in 1855. In speaking of this eruption Dana says that there was no earthquake, no enternal thunderings, no premonitions at the base of the mountain. A small glowing point was seen at a height of 12,000 feet, which gradually expanded, throwing off coruscations of light. A vent or fissure then formed, from which a vast body of liquid lava rapidly but quietly flowed during several weeks (a later account says 10 months), forming a stream of lava which extended a distance of 65 miles, with a breadth of from 3 to 10 miles. He adds that those eruptions of fiery cinders which mark so strikingly Vesuvius, are almost wanting about the craters and eruptions of Mauna Loa, and the few that there are, are mainly in connexion with the lateral cones. On the other hand, Mr. Scrope remarks that the great paroxysmal eruptions of volcanoes are preceded by earthquakes more or less violent, frequent, and prolonged, ‘“‘and begin generally with one tremendous burst, which appears to shake the mountain from its foundations. Explosions of aeriform fluids, each producing a low detonation and gradually increasing in violence, succeed one another with great rapidity from the orifice of eruption, which is in most instances the central vent or crater of the mountain.” As a con- Sequence of such eruptions, the cone is frequently found truncated, “the upper part having been blown off, and in its place a vast chasm formed, of a caldron-like appearance, and of a size proportioned to the violence of the eruption and its duration.* One of the most violent of the explosive eruptions was that of the Cosequina in 1835.f This volcano is situated on a promontory south of the Bay of Formosa in Central America. The detonations were so violent that they were heard at a distance of 280 miles. So enormous was the quantity of ashes and scoriz shot out of the crater, that for a distance of 25 miles they covered the ground to a depth of about 15 feet, and the finer dust was carried by the wind as far as Jamaica, a distance of 800 miles. It is not recorded that this great outbreak was accompanied by any lava-flow.{ The mountain itself is only 480 feet above the sea-level. From time to time the violence of other paroxysmal eruptions has blown off and truncated the cone of the volcanoes, and enlarged the craters, from the small dimensions they have when the eruption issues at the finished apex, to gulfs sometimes several miles in circumference and of great depth, eviscerating, as it were, the very centre of the * “ Volcanos,’ 2nd Edit., pp. 20-21. + The great eruption of Krakatoa has taken piace since this was written. It was one of the same character ; we wait the report now preparing by a Committee of the Royal Society. t Reclus, “ La Terre,” p. 668. VOL. XLI. K 130° 3 Prof. J. Prestwich. mountain. Scrope* mentions as examples of such paroxysmal erup- tions,—13 eruptions of Vesuvius, 8 of Etna, 2 of Teneriffe, 1 of San: Georgis in the Azores, 3 of Palma, and 1 of Lancerote (Canary Islands), and all the recorded eruptions of Iceland. “Sometimes in these eruptions no absolute escape of lava takes place, scoriz alone being projected. In all cases when lava is emitted its protrusion marks the crisis of the eruption, which usually attains a maximum of its violence a day or two after its commencement. The stopping of the lava in the same manner indicates the termination of the crisis, but not of the eruption, for the gaseous explosions continue often for some time with immense and scarcely diminished energy.” ¥ It seems to me therefore evident from these and such other cases, that there is no definite relation between the quantity of explosive gases and vapours and the quantity of lava discharged from the volcanic foci. It is conceivable that the enormous force of some of the explosions may, in the paroxysmal outbursts, shatter and blow to fragments all the lava as it rises in the crater, but this seems hardly sufficient to account for the proportionally large quantity which should accompany such vast volumes of vapours, were those vapours * the cause of the extrusion of the lava. It is still more difficult to conceive on this hypothesis the excessive discharge of lava in tranquil eruptions without a greater escape of vapour. If the escape of lava depended altogether on the escape of the im- prisoned vapours, it 1s not easy to see how the constant supply, whether of the lava or of the steam, is maintained. The rise and escape out- wardly of the lava in a volcanic vent has been likened to the boiling up and over of any other thick and viscid matter exposed to heat from beneath in a narrow-mouthed vessel,t and Constant Prevost compared it to the overflow caused during fermentation by the evolution of car- bonic acid gas. But the cases are not analogous. In the one the aeriform fluid is part of the substance of the vaporisable matter, which is not the case with the lava where the substance causing ejection 1s foreign to it. In the first case the elastic fluids are generated by a molecular change of the heated substance itself, and the supply is therefore, so long as that lasts, unlimited ; whereas in the case of lava, which cannot undergo such changes, it is only the supposed occluded vapour in it, that, with the relief of pressure would be subject to expand and escape, and thereby displace and expel a proportionate quantity of the lava. Besides, could that result take place before the lava began to rise? If not, there must be an independent cause to originate the rise. We might also ask whether that very rise of * “ Volcanos,” p. 25. + Ibid., p. 23. { Scrope’s “ Volcanos,” p. 40, and Lyell’s “ Principles,” vol. ii, p. 221. On the Agency of Water in Volcanic Eruptions. 131 the lava in the duct would not on the contrary increase the pressure in the volcanic foci in which the occluded vapour is present ? We have already pointed out the difficulty of accounting for the introduction of water into the volcanic foci. Hven supposing it to be introduced and to cause a boiling over, that ebullition would go on so long as any of the imprisoned vapour remained in the lava; but when the expulsion of one or the other was effected, then the introduction of fresh materials from the outside, as in the case of the water in the Geyser pipes, would become necessary, or the boiling over of the lava would cease for want of supplies. If the water were present in combination with the lava in the volcanic foci, there is no reason why the passage to the exterior once formed, the eruption should cease until all the mass susceptible of boiling over should be expelled, in which case each eruption would be of longer or shorter duration, and a volcano would become extinct after one eruption. If, on the other hand, the expulsion were due to the access of water from the exterior, whether by fissures or by permeation, it is dificult to imagine such an influx of water without the previous action of some disturbing cause whereby the existing equilibrium under which the descent of the water is stayed, would be destroyed. The only logical hypothesis on which I can conceive the vapour of water of gases to be present in the fluid magma of the volcano is the one suggested by Dr. Sterry Hunt, who considers that the magma is not part of the original molten anhydrous nucleus of the earth, but an intermediate layer derived from the first outer crust of old surface rocks which had been exposed to meteorological agencies, and retained, when fused under pressure, the water with which they had become permeated when on the surface. He supposes the original nucleus to have gradually become solid by pressure and loss of heat, and an outer crust to have formed. As that crust became thicker and covered by sedimentary strata accumulated upon it, its under surface, owing to the rise of the isothermal bars, was gradually remelted, forming an intermediate fluid layer between the solid nucleus and the solid outer crust. Or else that of Mr. Fisher, who, from investigations in which he com- pares the existing inequalities of the earth’s surface with such as could possibly have arisen from secular cooling, concluded that the interior of the earth had shrunk more than mere cooling alone would account for, and suggested that this was due to the presence of superheated water in large quantities in the original nucleus, and that the blowing off of this water during volcanic eruptions might have contributed materially to the diminution of the volume of the magma.* In a sub- sequent work} Mr. Fisher has applied this hypothesis more particularly * “Trans. Cambridge Phil. Soc.,”’ vol. xii, p. 414. + “ Physics of the Earth’s Crust,” chap. xv, p. 185 e¢ seq. K 2 1:32 Prof. J. Prestwich. to the explanation of volcanic action. He supposes a solid crust of about 25 miles thick resting on a fluid substratum of highly heated rocky matter in a state of igneo-aquecus fusion, and shows that if a crack were produced by any cause in the under surface of the crust it would become filled with the water substance or vapour given off from the fluid magma at a high tension. Whenever the rent, commencing below, opens upwards, vapour at a high tension will escape, and after a certain time will be followed by the magma itself, which will overflow at the surface because the water-substance expanding, owing to the dimi- nished pressure, will render the whole column of less weight than an equal column of the crust. On this view he considers that any disruption in the crust which is sufficient to permit the passage of steam at an enormous pressure, would originate a volcano; and “‘ much of the lava poured out might consist of the materials of the crust itself, fused by the passage of the gases through it, and so vary in its compo- sition at different vents, and even at the same vent at different times.” I need not dwell on the other objections I feel to these hypotheses because the special one before-named applies equally to this, —namely, that, if they were true, all rocks formed under such conditions should exhibit evidence of the presence or of the escape of vapour. All volcanic matter should be more or less scoriaceous, whereas there are many lavas which are little, and others not at all scoriaceous; while the great sheets of basaltic rocks which have welled out from fissures at former geological periods, are likewise neither scoriaceous, except very superficially if at all, nor are they accompanied as a rule by débris indicating explosions and projections due to the presence of vapour and gases. Why also should not all rocks of igneous origin, as well as voleanic rocks proper, be scoriaceous, if such were the conditions of the molten magma beneath the solid crust? The general want of hydration in Sian rocks and their associated minerals is likewise incompatible with such conditions. It has been contended by some writers that large subterranean cavities may exist at depths in the earth’s crust, and that the vapour of water under high pressure may be stored up in such underground cavities. But the pressure of the strata is so great at depths, that, as in deep coal pits, where no permanent cavities can be formed, owing to the “‘ creeping”’ and falling in of the strata, it would be impossible for such cavities to exist in Sedimentary Strata, while in Igneous rocks the initial plasticity of the rock and pressure would effect the same object. Even if such cavities did exist, they could only be maintained by the action of an elastic fluid, whose pressure would exceed that of the superincumbent strata. Geology affords no evi- dence of such underground reservoirs, or of any having existed in former times. No great explosions of pent up steam show themselves during the disturbances, shocks and rents accompanying earthquake On the Agency of Water in Volcanic Eruptions. 133 movements, and no persistent issue of steam gives countenance to the supposition that the water permeates the rocks to great depths or exists there in natural cavities. Natural cavities at depths in the earth’s crust I hold to be impos- sible. There may be cavities in the Igneous rocks near the surface, due either to contraction, to rapid cooling without pressure, or to the shell left by the escaping lava streams. But these cannot take place at great depths. ‘They are connected with subaerial action. With regard to such cavities as those so common and of such extent in limestone rocks, it must be remembered that these cavities are entirely due to the descent of the surface waters to a definite level, and to their escape by the most readily available outlet, either in adja- cent valleys, or at or near the tide line on the adiacent coast. Below that level there can be no active circulation of water, and no possi- bility, therefore, of great cavities, due to the passage of water through underground channels, being formed. Changes of level may have carried some of these superficial cavities to certain depths beneath the surface, but that they should have been carried to the great depths we are referring to, or be of any sufficient size, is more than problematical. In limestone strata they occur near the surface, or at a short distance beneath the surface; wherever these rocks have been worked at a depth beneath the line of water saturation, such cavities are of very rare occurrence. Deep mines reveal occasionally a few fissures, and some comparatively small cavities, but these are in mineral veins, which show no relation with active volcanic phenomena. : § 3. Influence of Volcanic Eruptions on Spring and Well Waters. It is a singular circumstance that although the presence of water in volcanic eruptions has been go long recognised, and the disturbances caused to wells and springs have been so often noticed, no systematic series of observations has been made either on the surface or on the underground waters in connexion therewith. There are many allu- sions and incidental notices, but nothing in the form of special and exact details. Most writers on the subject speak of the disturbances to wells and springs as a common or obvious fact; but a series of extended and accurate observations is much needed.* In the absence of more exact data, we have to avail ourselves of general observations made by witnesses on the spot, amongst whom are many competent authorities. The great eruption of Vesuvius of 1813-14, which commenced with a few trifling explosions and shocks in September, and by a small eruption of lava in October and November, followed by the great * The observations should rot be limited to the volcanic area, but should extend to the sedimentary strata around, and to some distance from the centre of eruption. 134 Prof. J. Prestwich. eruption of December, was witnessed by M. Menard de la Groye,* who remarks that ‘‘ towards the end of May the well-waters of Torre del Greco and Torre dell’Annunziata failed, and that this was an ordinary precursory symptom of the eruptions.’’ In June the waters continued further to lower, and “‘in the first fortnight in July they fell so low as to alarm the population,’ while ‘‘in October the wells of Resina, Torre del Greco, and other places failed in a surprising manner.” Professor Phillips briefly recordsy the following instances :—“‘ July, 1804. Severe earthquake—diminution of springs.” In May, 1812, the wells failed or were much lowered at Torre del Greco and Resina, as well asa thermal spring. In June, July, and August, heavy rains occurred ; yet this did not restore the water in the wells, which still remained low, and even lower than before in September, and this scarcity was felt along the whole Vesuvian coast, and in the valley of the Sarno. LHarly in 1822 the wells lost their water. August, 1833, water failed in the wells.t| The loss of water has sometimes been attributed to other causes, such as the state of the rainfall, &c., but Professor Phillips specially observes that this sinking of the wells cannot be explained by reference to the previous state of the weather ;§ and, after a careful examination into all the phenomena connected with the eruptions of Vesuvius, he alludes again to “the sinking of water in the wells around Vesuvius—the total drying up of some, and the increased descent of the bucket in all,” during times of volcanic disturbances, as an important fact. M. Ch. St. Claire Deville|] remarks: ‘‘ It is well known that there is only one tolerably certain indication of an approaching eruption of Vesuvius, and that is the disappearance of the water in the wells of Resina and Torre del Greco.” According to Poulett-Scrope,§/ the threatening indications of an approaching crisis “‘are accompanied by the disturbance or total dis- appearance of springs, and such accidents as the cracking, splitting and heaving of the substructure of the mountain must naturally occasion.”’ Professor Guiscardi, of Naples, in answer to my inquiry, writes,** “As a rule, the water of wells in the neighbourhood of Vesuvius undergo changes in quantity, and even quite disappear before the com- mencement of eruptions. Only as well as I know in the eruption of 1861, the phenomena followed the eruption. I add a list of such diminishing and drying wells. * “ Journ. de Phys. et de Chim.,” vol. lxxx, p. 390. t ‘* Vesuvius,” p. 96 e¢ seq. t Ibid., p. 140. § Ibid., p. 141. || “ Bull. Soe. Géol. de France,” 2nd Ser., vol. xiv, p. 254 (1856). { ‘ Volcanos,” 2nd Hdit., 1862, p. 21. ** Letter to the author dated 1st Sept., 1881. On the Agency of Water in Volcanic Eruptions. 135 “1843. Decrease of water in the wells of Resina; it was preceded by emission of lava. ©1846. Some wells of Resina dried, and emission of lava fol- ' lowed. “1846. Six adventive cones in the crater; water decreases at Resina in wells. “1847. Decrease of water in the wells of Resina; great lava flowing. | “1848. Water decreases in the wells of Resina and Torre del Greco. Harthquakes in the neighbourhood of Vesuvius. Lava flowing. “1849. The same decrease of water—strong explosions, bellowing, and lavas. “1850. January 23rd, at Resina and Torre del Greco decrease of water in wells. Strong explosions. February 5, lava poured out with bellowing. “ Before the eruption of 1794, there was at Torre del Greco a small torrent, capable, it is said, of moving four mills. After the eruption the torrent got very poor, so that the water scarcely supplied a foun- tain. After the eruption of 1861, there was an increase of water in this fountain, and in some small springs near the shore, and one was noticed in the sea itself, which lasted nearly a month. “There is a well on a farm of some relatives of mine, at St. Georgio di Cremano, in right line nearly 4: miles from Vesuvius, 150 feet deep, and plentifully fed by a spring. After the eruption of 1861, the water began to decrease, and a year after it was quite dry. This was followed by so abundant an emission of carbonic acid, that the well had to be stopped up.” I must observe, however, that the high authority of Professor Palmieri is against this view.* He states that previous to the eruption of Vesuvius in 1871-72, the water in the wells was neither deficient nor scarce, but was very acid afterwards. He elsewhere mentions that he considers these supposed premonitory signs either only to happen occasionally, or to be mere coincidences, such as the coinci- dence of a dry or rainy season. But the weight of evidence is certainly against this opinion, and, as I shall presently explain, there may be tracts that have an independent water-level which escape the surrounding disturbance, and it is not impossible that this very cir- cumstance has led to the selection of such areas for the sites of towns and villages on the slopes of the mountain. The more local springs which supply the shallow surface wells may remain undisturbed, while at other points the deeper-seated springs having a wider range may be tapped and drained. Again, the water in * “The Hruption of Vesuvius of 1872,” translated by R. Mallet, F.R.S., p. 135. 136 Prof. J. Prestwich. the superficial volcanic strata will usually flow towards the circum- ference of the mountain, in consequence of the beds by which they are held up dipping from the central crater; while the springs in the sedimentary strata lie in the continuous planes traversed by the vol- canic duct, and towards which they may often dip. Some irregularity in the phenomena is therefore to be expected, and while in most places the wells suffer, it is quite intelligible that in others they may be but little affected. Fig. 1.—Diagram section of a volcano. The dark bands represent lava-streams ; the dotted spaces, ashes and scorie ; and the line /, the water level in the mountain. As bearing upon the subject of the disturbances to which water- bearing strata are liable in volcanic districts, we have the evidence of M. Mauget, a well-engineer of great experience, respecting the sudden changes of water level in the Neapolitan area, during his residence there. There were eruptions of Vesuvius in 1865 and 1867, but none in 1866. Nor were there any important earthquakes, but a number of minor ones are recorded. M. Mauget says that in May, 1866, the wells and springs around Naples began to be affected, and continued to diminish until June, but considers that this might be due to ordinary causes, such as lesser rainfall. On the 29th June a sudden change took place. ‘The waters of the aqueduct, which brought in the water from a distance of 12 miles, and of the canal of Lagno di Mofita, as well as of various rivers, became troubled and reduced in a surprising manner. The next day the waters became bright, but were found to be reduced to the extent of one-fifth of their volume. The great springs of the Sannio district were reduced by one-third; and the town of Sorrento was de- prived of all potable water. This water is brought in by an aqueduct from the neighbouring hills, which consist of Hocene or of Cretaceous strata. The whole district, from the foot of the Apennines to the Neapolitan coast, was affected over an area of 66 miles square. At the same time various artesian wells in the valley of Sebito became sanded up and greatly reduced in their flow, and the two deep artesian wells of Naples threw up above 200 cubic métres of trachytic and pumiceous sands and lapilli.* It is evident that this diminution in the surface waters could only * “ Sur les variations subites dans le régime de divers cours d’eau dans Italie Méridionale,” “ Comptes rendus,” vol. lxiv, p. 189 (1867). On the Agency of Water in Voleanic Eruptions. 137 have been caused by their absorption under ground, either to restore some water level reduced by a former eruption, or to fill fissures in course of formation preceding the eruptions of 1867 and 1868. It seems to me, therefore, to use the words of Professor Phillips, that the observations respecting the effects produced on wells and springs by volcanic eruptions and earthquakes, ‘“‘ have been too often and too carefully made to allow of a serious doubt on the subject ;” he asks, ‘‘ What is the cause of it P and why is it an indication of coming | disaster P”’ § 4. The Hydro-geological and Statical Condition of the Underground Waters in and under a Volcanic Mountain. The cause is, I believe, not far to seek, when the hydro-geological conditions of the strata composed above of volcanic matter, and below of sedimentary strata, are considered. So well known is the absorbent power of a volcanic surface, that the mention of the fact hardly seems necessary, except in corroboration of subsequent statements and for the purpose of independent testi- mony. On ordinary strata it is roughly estimated that about one- third of the rainfall passes under ground, but on volcanic surfaces the whole rainfall soon disappears, a small proportion only being lost by evaporation. Amongst innumerable notices of this fact, it will suffice to mention those of two experienced authorities. Lyell re- marks on the dry and arid surfaces of Htna, and on the rapid absorp- tion of the rainfall, and observes that ‘‘ the volume of rain-water and melted snow commonly absorbed by a lofty mountain like Htna, is enormous ;* again, Piazzi Smyth, in describing his ascent of Teneriffe, says, ‘‘that though so much rain had fallen lately, not a trickling stream, not even a drop of standing water, was anywhere to be seen; the pumice-stone ashes had swallowed all up.” + - Voleanic mountains being composed of streams of lava of very vari- able width and length, irregularly alternating with more widely spread layers of scoriz and ashes, the whole mass would be permeable were it not that the decomposition of some and the consolidation of other beds, by atmospheric and aqueous agencies, have formed here and there impermeable beds, which hold up the rain-waters, and furnish local supplies to wells and springs. But where such impermeable beds do not intervene, the rain-water penetrates to greater depths, and is there stored until the line of water-level reaches to such a height that the hydrostatic pressure forces it outwards, and causes it to escape at the points J as springs either temporary or perennial (fig. 1). _ This storage may take place either in the lava or in the beds of acoriz and ashes. Solid lava is impermeable, but water penetrates * “ Phil, Trans.,” vol. 148 (1858), p. 763. + “ Teneriffe,’ p. 349. 138 Prot. J. Presacich! through, and is held in, the numerous fissures and cavities by which it is traversed. These fissures are due to contraction on cooling, and to the fractured state of the lava produced by the split- ting caused by subsequent disturbances, whilst larger cavities are produced by other causes. Of these, the two most important are— Ist, the escape of vapours while the lava is consolidating. Sometimes the hardened outer crust of the lava is raised in great blisters, which, on the escape of the vapour, are sufficiently solid to retain their posi- tion, and remain like so many empty beehives on the surface of the lava streams. The Grotta delle Palombe, on Htna, which, according to Waltenhausen, has a length or depth of about 500 feet, and a height in places of from 70 to 80 feet, and the great ice cave near the top of the Peak of Teneriffe, described by Piazzi Smyth,* and so large as to contain a lake of water of considerable size, are attributed by them - to the escape of elastic vapours.. 2nd, the escape of lava from a lava stream after the exterior of it has become solid, when an empty. shell in the form of a cave or tunnel is left. These tunnels or caverns are of common occurrence, and often of large size. Scrope observest that “‘among the lavas of Etna, Bourbon, Iceland, St. Michael, Teneriffe, and many others, caverns of very large dimensions are thus formed beneath the surface of a lava stream, and often imitate in their extent and windings the well-known caves worn by water in limestone rocks.” Phillips and others notice the occurrence of similar tunnels in the lavas of Vesuvius, but they are all small. In the great volcanic mountains of South and Central America, Humboldt long ago inferred that large cavities filled with water must exist in consequence of the ejection of water, with small fishes and tufaceous mud, from fissures caused by the earthquake shocks which precede the eruptions of the volcanoes in the Andes.f A French geologist, M. Virlet d’Aoust, has, moreover, given particu- lars of two great tunnel-caverns of Central America,§ which will serve to indicate the magnitude of some of these subterranean reservoirs. The first is that known as the Cueva de Chiuacamoté, near Pérota, which he was assured extended several leagues in length(!) He found it to be a cavern of great size, and divided into compartments by falls of the roof. The floor is covered with a sandy gravel, and the side walls, here as in the cave of Custodio, exhibit grooved lines covered with slight calcareous incrustations indicative of old water- levels. The other is the Brefia de Custodio, in the State of San-Luis Potosi, of which he says that it forms a perfect semispherical tunnel * “ Teneriffe,” p. 352. ¢ “ Volcanos,” 2nd Hdit., p. 79. t “ Cosmos,” Sabine’s Translation, vol. 1, p. 230. § “ Bull. Soc. Géol. de France,” 2nd Ser., vol. xxii, p. 34. On the Agency of Water in Volcanic Eruptions. 139 of the size of our largest railway tunnels, at its end dipping towards the centre of the mountain. Cavities originating in these ways must have been formed at all times and in many lava streams, and although a certain number of them, especially those due to the upward escape of elastic vapours, may have been filled up by succeeding lava streams, this would not be the case with tunnel-caverns opening downwards. Nor would these streams always fill up even open fissures, as they push before them a mass of solidified débris, which forms a pavement protecting the underlying mass. The lava throughout a volcanic mountain may therefore contain a greater or lesser number of caverns, which serve, whenever they happen to le below the normal line of water-level, as so many reser- voirs. The mass of the lava is further riddled with fissures of all dimensions, which act as water-channels and channels of intercom- munication. Again, the beds of scoriz, ashes, and tufaceous deposits serving to build up volcanic mountains, and which overlap the lava streams, and extend to considerable depths, are often water-bearing. Some contain powertul springs, hike stratum No. 4, which was met with in the Palace well ata depth of 368 feet beneath the surface at Naples (p. 141). The shallow surface wells of the district are commonly in beds of this character. Even the more impermeable tufaceous beds contain cavities which when under the line of water-level, must serve as reservoirs. These cavities, which attain a size of 2 feet or more in height, and are lengthened out in a vertical direction, like the flues of chimneys, have been formed by the disengagement of elastic vapours during the con- solidation of the beds, that consist, in the Naples district, of volcanic tuff with trachytic and other rock pebbles.* These beds have a wider extension than the lava masses, which further decrease in importance as they trend from the central area of eruption.+ The dykes running in vertical lines through volcanic mountains form another structural feature having an important bearing upon the question under consideration, for they traverse radially the beds of ashes, scorie, tufa, and lava wrapping round the central duct, with which they serve to place them in communication. Besides these great radial dykes, which are often extremely numerous, there is a network of small fissures or dykes branching off from them in all directions. During the eruption of Hina in 1865, a rent was formed at the * Dufrenoy, ‘‘ Ann. des Mines,” 8rd Ser., vol. xi, pp. 113, 120 (1837). + Some volcanic mountains are, however, composed almost entirely of ash and scoriz beds, and others of lava streams; the line of water-level will be modified in accordance with these conditions. 140 : | Prof. J. Prestwich. crater of Frumento, which extended in a direction away from the central cone for a distance of 15 mile. Scrope says that in nearly every lateral eruption of Etna, the production of such a fissure has been observed. Similar instances are not wanting in Vesuvius. In 1738 a fissure crossed the whole island of Lancerote; while in the great eruption of Hecla of 1783 the fissure which was then formed was supposed to extend not less than 100 miles in length.* Fig. 2.—Diagram plan of a volcano, showing the radial lines of fissures or dykes. | Scrope further remarks that “‘the rents thus produced in the frame of a volcanic mountain are sometimes of such a size as to cleave its whole mass in two. This occurred in the volcano of Inachian, one of the Moluccas, in 1646. The crater of the Soufriére of Montserrat, and the volcanic cone of Guadaloupe both appear to have been thus split through. So also the Montagne Pélée of Martinique.” Piazzi Smyth states that the cinder beds surrounding the summit of Tene- riffe are traversed’ by dykes proceeding in radial lines from the Peak.+ Phillips describes some of the dykes and fissures of Vesuvius, and gives | a section showing the relative position of the ejected débris and lava beds of this mountain, and of the dykes radiating from the central core. These dykes, like other masses of lava, have generally become fissured in cooling, and the interstices thus formed serve as water channels, not only for the rain which falls upon them, or to small springs high up the mountain as in Teneriffe,§ but, what is more im- portant, they may serve as channels of drainage to the water-bearing scoriaceous and lava beds which they intersect. For it will be under- stood from the preceding account that these latter beds may often “ Volcanos,” 2nd Edit., 1862, pp. 161—163. “ Teneriffe,” p. 80. “ Vesuvius,’ pp. 132 and 191, and Pl. VI. “ Teneriffe,” p. 86. t+ —-+ On the Agency of Water in Volcanic Hruptions. 141 form independent and isolated water-reservoirs; but, traversed as they are by dykes communicating with the central mass, these dykes serve as so many conduits to carry the water from the separate water- reservoirs and drain them into the central duct (fig. 2) whenever the normal hydrogeological conditions are disturbed. At such times the dykes therefore contribute greatly to the discharge of water into the interior of the volcano. Very little is known of the substrata of a volcanic mountain. We know that Vesuvius, Etna, and Hecla stand on Tertiary strata—-that some volcanoes in America stand on Cretaceous or Jurassic strata, and others probably on crystalline rocks, but of the stratigraphical details underground we have very scanty information. The only instances that I am acquainted with are the sections obtained in boring for the two artesian wells constructed in 1865-66 at Naples by MM. Degousée and Laurent, of Paris. These supply very important data not only respecting the volcanic beds, but also respecting the sedimentary strata beneath. One well is situated in the Piazza Villa-Reale, and was carried to a depth of 1106 feet, and the other, in the gardens of the Royal Palace at Naples, 72 feet above the sea-level, was carried to the depth of 1524 feet. The details given of this latter by M. Laurent are as follows :—* _ Section of Artesian Well in the Palace Gardens, Naples. Thickness. Depth. métres. metres. ( 1. Soiland made ground .... 16°50 16°50 2) Wellow volcanic tufl,.. 5...) ) 0200 69°00 3. Green = the eect Css oles 33°00 102:00 4. Voleanic ashes, in places Volcanic argillaceous, and containing ejecta- < numerous pebbles of tra- menta. Clyey ate chataiey spas Ist spring 103°40 205°40 ©. Greenish volcanic tuff .... 7°00 212°40 GaiGirevclayian..)vas. 8 6 senso « 8°10 220°50 | 7. Grey marly tuff with tra- ij ClyGes, cota je orale Be eienailehi seria 4-00 224°50 ( 8. Sandy marl with veins of APormmibes Mere ey ed icice aie aco kas 25°00 249°50 9. Grey marly and bituminous Sub- sands, with mica. 2nd spring 27:00 276°50 Appenine < 10. Hard sandstone .......... 1:80 278°40 strata. 1) Compact shelly marl ...... 44°80 323°20 12. Alternating micaceous sands, soft sandstones and carbo- naceous marl....3rd spring 48°70 371°90 * “ Guide du Sondetr,” 2nd Edit. 1861; vol. i, p. 187; u, p. 496; and Pl. L. 142 Prof. J. Prestwich. Thickness. Depth. meétres. metres. (13. Micaceous mar] and siliceous Sub- | limestone, jaa / en 2 ) if =, pm w BS co Seed MILLIMETRES MEASURED EVERY. 2 MINUTES (o>) oO oO oO 218 Dr. J. T. Cash. Experiment II (Chart I (continuous line, diagrammatic), and Curve I).—The dog had not been fed for nineteen hours. A small sound consisting of $ gram of lean meat on which a little piece of tendon was left, was attached by a thread to the pen already described which moved vertically upon guides. This sound was introduced deeply into the upper fistulous opening. The following notes indicate its progress through the fistula :— Experiment IJ, Curve I. Reduced scale= 3th. 0’. Sound introduced into the intestine. 4’, Definite peristalsis has commenced ; animal sleeping. 7’. Roused; a little movement with deep respiration. 17’. Again asleep; gentle peristalsis. 19’. Started in sleep and awoke. The loop of intestine was evi- dently twisted or moved away from former position (roll move- ment) to which it shortly returned ; again sleeping. — 21’ 5". Roused. Deep respiration with slight peristalsis. 33’. Propulsive peristalsis, strong and regular. Dog roused just before expulsion of sound from the lower opening. (The meat was not in the least degree digested.) It will be observed that during sleep the sound continues to travel forwards with considerable regularity. In all 12 cm. of the fistulous intestine is traversed in forty minutes. The experiments of Ranvier have shown that if a travelling sound which is passing down the esophagus be hindered in its transit by traction being exerted upon a thread connected with it, the contrac- tions become inoperative, i.e., fail to forward the body, and then cease, the muscular tube becoming ‘“‘ accustomed” to its presence. The same holds good if we introduce a moderately large sound into the intestinal fistula and allow it to travel. The fact of its introduc- tion and presence favours its passage onwards for a certain distance with considerable rapidity; but if gentle traction be made on the thread after a period of active but futile contraction,* rest occurs and no advancement takes place till a new phase of activity develops itself. * These contractions are local. I have hardly ever seen them pass the body whose presence is to a large degree the cause of their occurrence and travel to a lower part of the intestinal tube. On Intestinal Rest and Movement. 219 It is thus that during a fasting condition, the sound being unrestrained, the first part of the fistulous intestine is traversed rapidly ; but that afterwards a marked diminution in speed occurs, whilst with a smaller sound moving freely, ora larger sound restrained for a time, the rapid initial peristalsis would not be observed. In illustration of this point I give the notes of an experiment. Experiment JIT, Chart II. Experiment VI, Chart V. ACTUAL CONTRACTION MILLIMETRES MEASURED EVERY 2 MINUTES Haperiment IIIT (Chart If and Curve II).—0’. Introduced large oblong sound (metal capsule, weight 3:4 grams, 18 mm. long by 9 mm. greatest breadth) into upper fistulous opening. Sound allowed to travel, no traction being made upon it but that occasioned by the weight of the pen (2 grams). Experiment III, Curve IT. Reduced scale= ths. 220 Dri Jz TS Cash 1'. Active propelling peristalsis; sound has travelled 2 cm. into intestine. 2’. Continuation of active peristalsis; sound advanced in all 52cm. (At this time effect due to the introduction of sound passes off, and advancement occurs more slowly; local non- - propulsive movements taking place from time to time.) 8'. Has advanced in all 7°4 cm. 14’. Has advanced in all 8:2 cm. 18’. Advancement has been slow; is now 10 cm. from upper open- ' ing of gut. At this point contraction becomes more active. 25’. 12°8 cm. traversed ; peristalsis succeeded by a pause. 29’. 12°9 cm.; pause in contractions. 35’. 16:2 cm.; active propulsive peristalsis reappeared. Capsule expelled fram lower fistulous opening. The total time occupied in the passage of the sound through 16°2 em. of fistulous intestine was 35’. eines Effect of Feeding.—I will now turn to the effect produced upon the fasting intestine by the introduction of food into the stomach. The method of experimentation will be at once apparent. A fixed or travelling sound was introduced through the fistula, and the condition of the fasting intestine, as regards its movement, was recorded. At a noted time the dog, whose head had been kept covered with ‘a cloth, had a series of pieces of meat given to it which it rapidly swallowed without changing its position on the table. (The covering of the head was a necessary precaution which I adopted in almost all the observations in order that this experimental procedure should not be associated in the mind of the animal with the administration of food only ; for if the dog saw meat when in a condition of hunger, or had its proximity suggested in any way, it was sufficient to produce an active though frequently transitory contraction in the fistulous gut.) The notes of the following experiment which was made when the animal was showing unmistakeable indications of hunger, will illus- trate the modification in an already existing peristalsis on the intro- duction of food into the stomach. _ Heperiment IV (Curve LIT).— 0’. Introduction of large sound, used in the previous experiment. 1'. Active peristalsis has commenced. 3'. Propulsive movements alternate with local or non-propulsive. 5’. The animai was somewhat excited by the movement of a plate on to the table on which it was lying. 7'5'. About 50 grams of meat were presented to the dog in pinges and rapidly swallowed. 10’. Intestine quiet, except for faint local movements around the sound. On Intestinal Rest and Movement. 221 Experiment IV, Curve ITI. ie ww Gf, we as AG. DL rdar, I (pease aes Minutes Reduced scale=ith. I’. Active peristalsis has developed, the sound passing with great rapidity onwards; so little relaxation occurs that the curve has the appearance of steps at some parts. 16’. Sound lying within lower fistulous opening through passage of which it is retarded by thick muscular and cutaneous walls, which somewhat overhang in this position. In order to render the alteration in the speed of peristaltic propul- sion more apparent, I formulate from the experiment the distance traversed by the sound in every two successive minutes. Distance accomplished by j , 3 sound in centimetres. Time after introduction of sound in minutes. Fasting. Fed. O 0) = 2 1°6 4. ZO —— 6 2°2 — 8 O°5 — 10 0°5 12 4°3 14 34> IL 16 2°2 Total for 8 minutes before food............ 5°3 cm. o GURDON Trach Gvepmicr cial wauersyelee on Guies If we employ a rapidly revolving drum, the time elapsing between the introduction of food into the stomach and the occurrence of con- VOL. XLI. Q 222 Dr J. Te Cash. traction is easily estimated. It is then found that the intestine from a condition of entire rest or very faint contraction frequently passes with great rapidity to a state of powerful and regular propulsive con- traction. If the movement be registered by a stationary sound connected with a manometer, the course of the contractions occurring at the part of the fistulous intestine surrounding the bladder is recorded. It will be observed then that the individual contractions develop gradually to a maximum, and thereafter decline rapidly, their rhythm or rate of recurrence being very constant throughout. Experiment V, Curve IV.—Administration of Meat to Fasting Animal during Absence of Contraction of Intestine (fixed sound and mercurial manometer). { ree ANALY ‘5 Seconds Heperiment V (Curve IV).—Dog fasting, sound, moderately dis- tended with water, introduced 3 cm. into upper fistulous opening. The contraction round the sound as a result of its mtroduction and extension occurred regularly at the rate of ten for 1’, After spontaneous movement had ceased the smell of the meat produced excitement with distinct contractions, which did not entirely disappear for 3’ 30". 0’ 0”. When rest had again intervened, a small piece of meat weighing 5 grams was given. 1’ 30". Another piece of the same size. Both of these were swallowed the instant they were presented. 1’ 45". Contraction commenced at the rate of seven in 40”. 3’ 20'". Active contractions reached their maximum. Some tonic contraction is still seen between active compression of the sound, so that the curve remains elevated above the abscissa. 4' 16". The active contractions which had been declining markedly for 30” came to an end,'and were succeeded by a series of short waves which lasted for 1’ till at 5'16”. The intestine came to rest. Five minutes later a piece of meat was again offered, faint move- ment being present at the time, the maximum of the powerful con- tractions was reached in 40”, in exact correspondence with the former experiment. In the first result there were nineteen well- On Intestinal Rest and Movement. 225 marked contractions, having approximately a maximal value; in the second there were seventeen. After the lapse of another five minutes, the administration of another piece of meat failed to arouse any contractions. Immediately after a full meal a travelling sound introduced into the upper fistulous opening is forwarded by a powerful and regular peri- stalsis to the lower opening and promptly expelled, no marked halt occurring during the passage. Not only do the local contractions manifest themselves to a striking extent, but writhing, &ec., rolling movements (‘‘ Roll-Bewegungen ”’) of the fistulous intestine are also observed. It is during this period that the most rapid propulsion of the sound occurs, relaxation between the contractions is very imper- fect, the sound being held without marked retrogression till the next powerful wave drives it onwards. The presence of abundant peristalsis in the small intestines gener- ally is evidenced by borborygmi and movement communicated to the abdominal parietes. The increase of secretion which is extruded from the lower fistulous opening, and to a much smaller extent from the upper opening, is very apparent. I select two experiments for illustration. Experiment VI, Curve V.—Fifteen minutes after full Meal. Reduced scale = ths. Haperiment VI (Chart V (broken line, diagrammatic) and Curve V). —Taken 15’ after a full meal (contrast this with Observation III made on the same day before the meal). Large capsule employed. The animal slept the whole of the time. Q 2 6’. Dr. J. I. Cash. . Sound introduced; pendulum movements for first minute. 5 advanced 7 mm. 99 99 20 99 . Movement of all intestine. . Sound advanced 60mm. The propulsion of the sound greatly accelerated. . Contractions eleven to the minute; relaxation between. Waves very imperfect. Sound advanced 111 mm. 6’ 30”. Sound advanced 142 mm. No marked pause takes place in the occurrence of the waves. A maximum rapidity of 38 mm. in the minute is attained towards the end of the curve. Contrasting this result with Observation III gives the relative speed of the progressive peristalsis in the two cases. ee eee | Sound travels Time after introduction of sound in minutes. Before food (hunger). | 15 minutes after food. cm. em. 2, 5°3 2°5 The progressive peri- stalsis stimulated by introduction of sound. 4, 0-2 3°5 6 0°4 5-1 7 30 3°1 8 0'8 cae Experiment VII, Curve V1.—See Chart VI. Reduced scaie=4ths. On Intestinal Rest and Movement. 925 The last experiment was made with a metal capsule, and in order to show that the nature of the sound has no marked influence upon the rapidity of propulsion immediately after food has been introduced into the stomach, I shall quote the results obtained when the meat sound employed in Experiment II was substituted for the metal capsule. It will be seen that whether the body to be forwarded by peristaltic movement be incompressible or soft and plastic, the result obtained is practically the same. Experiment VI (Chart and Curve VI).—The dog had finished a full meal six minutes before introduction of the sound. 0’. Introduce meat sound deeply through the upper fistulous open- ing. Animal sleeping. a 11 mm. traversed. 2! es tas 5 ae “ Very strong peristalsis with some 3. O27. 1 “roll” movements of the loop of AV, Ome: ‘A intestine. ee Oo e Animal awake, deep respirations. 6. KOSS es pf rg Ti eae as Sheth ; gt 119 ight delay towards lower mouth of 4 %@ fistulous tract, the last 2 em. of which / ¢ ei = om * seems occasionally to act more feebly as ‘ she than the rest. Tabulated with the results of Experiment II (Chart I) the speed of propulsion is relatively the following :— Sound travels Time after introduction of sound in minutes. Before food (hunger). Six minutes after food. cm. cm. 0 0) 0 2 O 3 °4 A 0°5 43 6 1 3°4: 8 1 2°6 10 0°3 2° 12 O — 14 0-1 us 16 0°6 ee ! t The sound traversed 11°5 cm. of the fistulous intestine of the fasting animal in 46’. fed i 6°57. »P) oP) 39 During the later stages of digestion, ¢.c., one and a half to three hours after a full meal, the transmission of a solid body through the 226 Dr. A Gash fistulous intestine is fairly regular and rapid. There is, however, more tendency to occasional pauses and to the development of local non-propulsive movement which often inaugurate a phase of peristal- tic activity. Four or five hours after a meal and until the recurrence of hunger—period of repletion—the progression of a solid body through the fistula is at its slowest, long pauses being frequently observed without the occurrence of any propelling contractions. Even when peristalsis is occurring it is slow, and has much of a forward and backward character, complete relaxation behind the sound succeeding an active local contraction. A short tabulated statement of the results of several experiments dealing with the speed of transmission of a solid body during fasting (hunger), digestion, repletion, &c., may be found useful for purposes of comparison. The average time for each centimetre of the intestine traversed is not of course of absolute value. Length of Average time Condition fistulous Total time | for each cm. Sonwdselnieee of animal. intestine occupied. | of intestine lata traversed. traversed. cm. / 4/ ua 4/ Fasting (a).. 15°25 20 30 1 30 Large metal capsule. .. (O)%. 9 150 1 40 Small s 3 (c) 15°5 27 30 1 48 Large * ma (d) 16 33 2 Cork, 9mm. x 14 mm. 7; (e) 15 38 2 30 Large metal capsule. e 12 40 3 20 Lean meat. After ex- ercise (g).. | 13°5 16 30 LZ Large metal capsule. Digestion (a).. | 14:2 6 48 0 26 Large metal capsule. (15’ after food.) Oe | 15°5 8 48 0 36 Lean meat. (8’ after food.) shame 2) es 14°75 13. 36 .O 54 Large metal capsule. (2h. 34m. after food.) Repletion(a).. 7°5 76 10 Large metal capsule. (4 hrs. after meal.) (The transit in the last case I have quoted is one of the slowest I have observed. During the first 10' there was a progression of 15 cm., preceded by a pause. Local non-propulsive movements followed by peristalsis succeed in 20' (4 cm. in 9’); passage of the next 3 cm. took 36’.) Some variation in peristalsis according to the sound employed became On Intestinal Rest and Movement. nied evident after a few experiments had been made with each. The introduction of the larger metal sound (9 x 14 mm.) was usually followed by a well-marked peristalsis occurring immediately after- wards (Experiment III), lasting for 1’ to 3’, and propelling the sound 2 to 5 cm. into the fistula of the fasting animal. With the cork sound of equal size, but lesser weight, the effect was the same; with the narrow capsule (6 x 14:mm.) and the meat fragment, this primary peristalsis of introduction was much less marked. After the period ‘of activity had passed, the time occupied in the transit through the entire length of the fistula appeared to be closely similar in the larger and smaller bodies ; in other words, those of greater size which at first excited motion soon ceased to do so, the intestine becoming ‘accustomed ’’—as the cesophagus does—to their presence. When a phase of activity is present, as during the time imme- diately succeeding the introduction of food into the stomach, all evidence that larger bodies contribute by their size to a more rapid propulsion through the fistula, is lost. (Jf there were greater varia- tion in the diameter of the sounds employed than existed in those used in these experiments, it is possible that some slight exceptions to this statement might be found.) Changes in Character of Peristaltic Contractions. Jt is not my purpose at the present time to enter into a minute examination of the character of individual peristaltic contractions occurring under various circumstaaces, although I have alluded to this question very briefly on page 214. As, however, the consideration of peristalsis, stimulated by the introduction of a large sound into the fistula, has been brought under notice, I can scarcely omit contrasting the nature of the waves produced in this manner (and which are very similar to those occurring in all portions of the fasting intestine), and the digestive peristalsis occurring in the same animal half an hour after a full meal. It is found on registering them upon a cylinder having a medium velocity, that the contractions occurring in the first (fasting) condition are much more numerous in a given time, frequently nearly twice as many as in the latter; that the individual contractions have a shorter maximum which is attained more quickly, and that their relaxation is more abrupt and complete. As a result we find that in spite of the greater number of contractions the sound advances further in the same time after food than it did when food had not been recently administered. Some hours after the meal the change is even more striking, long periods of rest occurring which are from time to time broken by a few faint contractions, having a sustained maximum and an imperfect relaxation. 228 Dr. J. T. Cash. The quotation of one experiment will illustrate these facts suffi- ciently. Experiment VIII, Curve VII.—Travelling Sound in Upper Fistulous Opening (quick drum). a. Peristalsis on introduction of large sound (before feeding). b. 3) bP) C. o in advanced stage of digestion. ,», Lower line indicates respiration. (after | Haperiment VITT (Curve VII, a, 6, c).—Dog fasting sixteen hours. Large travelling sound (9 x 18 mm.) introduced into upper fistulous opening. Record on drum of medium velocity. On a, 30’. In 80” succeeding introduction of sound twenty-three contrac- tions occur (a). Average length of each contraction 3°3”. Total advance of sound 28 mm. Sound removed. Full meal of meat given to dog. Sound again placed in upper opening. (Slight irregularity in curves caused by tremor of animal, which often occurred for a time after meal, and to a lesser extent by respiratory move- ments.) In 80” succeeding introduction of sound, fourteen contractions occur (b). Average length of “forwarding ” peristaltic waves 5”. Average length of two contractions succeeded by a more complete relaxation occurring in the middle of tracing 3°3". Actual advance of sound 38 mm. 4 hours. At time of registration contractions take place at the rate of six and a half in 80". Sound advances at rate of 10 mm. in 80” (c). Contractions which are long maintained recur for 20" to 60”, and are succeeded by pauses of several minutes’ duration. This change in the rhythm, character, and potentiality of the peristaltic contractions shows how extensive the range of adaptation of these movements to the necessities of the time must be. Ory Intestinal Rest and Movement. 229 In the experiment quoted we see (1), vigorous propulsion accom- plished by frequent repetition of contraction; (2), more vigorous propulsion accomplished by fewer, but more sustained contractions ; and (3), the leisure and cccasional movement of the intestinal tube which would be favourable to active absorption. Direction of Propulsion of Bodies introduced into the Fistulous : Openings. The result of an examination of this question experimentally may be given in few words. Peristaltic progression in the fistulous intestine is always in the physiological direction. If the sound be placed well within the lower mouth, it is invariably rejected from this mouth. Very occasionally a sound introduced just within the upper mouth, but not far enough to be thoroughly “‘ gripped,” may be expelled by the same opening, but after it has passed 2 cm. into the fistula, this retrogression is never seen. A slight anti-peristaltic movement observed on the introduction of water into the fistula will be described below. Two Solid Bodies in the Fistula at the same Time. This experiment was performed with a double sound and register- ing apparatus. ‘The second sound, which was introduced after the first had passed several centimetres into the fistula, was perforated for the free passage of the thread connecting the latter with its pen. It was found that the condition of peristalsis or local contraction was not necessarily common to the whole length of the fistulous intestine, and that therefore movement of one sound occurs frequently quite independently of the other which lies within a few centimetres of it. On several occasions a distinct alternation in movement was observed, one sound resting whilst the other advanced. The first sound, ¢.e., that nearest the lower opening of the fistula, seemed usually to travel more rapidly than the other, and therefore to gain upon it. This fact may speak for a slight stimulation originated by the presence of the upper sound when at rest, favouring a more pronounced peri- stalsis lower down the intestinal tube. Upon this point I am seeking for further information. The introduction of water or almost any liquid, whether cold or at the body temperature, into the upper end of the fistula through which the sound had already passed, was invariably productive of some slight anti-peristaltic movement often associated with writhing or rolling of the intestine, the result being a retrogression of 2 or 38cm. This reversed movement, which lasted for 2’ to 5’, was suc- ceeded by a return of propulsive peristalsis which frequently showed a marked acceleration. - 6 SO ee 230 On Intestinal Rest and Movement. Experiment JX, Curve VIII. Reduced scale= 3th. Haperiment [IX (Curve VIII).—Injection of 5 ¢.c. of water at the fourth minute into the upper fistulous opening, peristalsis being present, caused on the first occasion a relaxation lasting for 4’, and on the second, between the twelfth and thirteenth minutes, for 2’, the pen falling 18 mm. After each of these injections the peristalsis became for a time more active. Propulsion of a.Sound upon which Traction is being Haerted. If the pen were weighted with a burden of 8 or 10 grams at a time, when the sound was being passed onwards by well-developed peri- staltic movement it was found that not only was the portion of intestine in which the travelling body was situated at the moment drawn towards the mouth of the fistula, but that the powerful con- tractions which occurred were incapable of materially forwarding the body. Even the traction caused by applying a weight of 5 grams to the pen produced much hindrance, and the spasmodic contractions induced and which had a propulsive character created a most distinct discomfort or colic. After the removal of the hindrance to effective transmission, the intestine unfolded itself, whilst the discomfort gave place to the most evident manifestations of satisfaction on the part of the dog, and active peristalsis—which was, however, soon reduced to its orginal character—took place. In contrasting this experiment with the well-known result obtained by Mosso, who observed that the cesophagus could hold a sound con- nected with a falling weight which exerted a traction of 450 grams, and forward one of but little less, the rectilineal course of the tube, and the fact that it is practically fixed at both ends—in both of which respects it acts at a far greater advantage than the intestine—m ust be borne in mind. I possess evidence, however, which I hope to be ina position to produce shortly, that even if these unfavourable conditions are obviated, the small intestine is physiologically unfitted for the systematic propulsion of bodies upon which more than a very On the Practical Measurements of Temperature. 231 moderate degree of traction is made. Fortunately this condition of traction upon a solid body already engaged in the intestinal tube can but rarely come into operation in the animal body, or it would un- doubtedly prove peculiarly difficult to overcome. Mechanical irritation of the lower mouth or upper mouth of the fistulous intestine, if persisted in, developed a powerful peristalsis which caused the rapid passage of a solid body through the fistula and its expulsion by the lower opening. Thus if the animal was induced—which it readily was—to lick the mouth of the fistula after the sound had been inserted in the upper opening, expulsion from the lower opening occurred in four to eight minutes. By moving a glass rod—passed within the mouth of the fistula—gently round or in and outwards, the same result was occasionally pro- duced, but not with the same speed or certainty. The consideration of the effect of electrical stimulation and of a number of drugs, upon whose action I believe new light will be thrown by this method of experimentation, I must leave to a future paper. I have purposely avoided entering into a discussion of the physio- logical rationale of the various phenomena I have described in this communication, because they cannot find their full explanation in the examination of a fistulous animal. This explanation must be sought by experiment of another character, and although much has been rendered clear to me by the ‘analytical research I have already made, other points are still lacking their complete elucidation. Until the latter research appears, I likewise postpone reference to the literature of the subject. To the Royal Society, which presented me with a donation in aid of this research, and to Prof. Hugo Kronecker, of Berne, who most kindly placed his laboratory at my disposal for its accomplishment, my best thanks are due, and I gladly take this opportunity of recording them. “On the Practical Measurements of Temperature. Experi- ments made at the Cavendish Laboratory, Cambridge.” By H. L. Canuenpar, B.A., Scholar of Trinity College, Cambridge. Communicated by J. J. THomson, F.R.S., Professor of Experimental Physics at the Cavendish Laboratory, Cambridge. Received June 9.—Read June 10, 1886. (Abstract. ) The experiments were undertaken with a view to investigate the possibility of establishing strictly comparable standards for high temperature ,measurements for which the air. thermometer is in- 232 Mr. H. L. Callendar. applicable or unsatisfactory, since even the best observers using all possible precautions disagree.* The platinum wire used was the purest obtainable, with an unusually high temperature coefficient, and very unalterable. If R; be the resistance of a given coil at 100° C., and Ry the resistance at 0° C., and R the resistance at any other temperature, the experiments abundantly prove (1) that with proper precautions Ry is constant to 0°01 per cent., even if the coil has been subjected for hours to a temperature of 1300° C. (2) For several different pieces of wire from the same reel it was found that the ratio ri was constant 0 to the same degree of accuracy, and equal to 1°3460. (3) That for two different wires of pure platinum, though the values of Bas Bo Ro ae 100, that is to say, of aE the temperature Centigrade by platinum —— agree to Q°l per cent. through the range 0—600°. The method of comparing the temperature variations of different wires is very accurate. The wires to be compared are interwound symmetrically so as to form a double screw thread on non-conducting material (e.g., clay), and are heated in a vacuous porcelain tube in a gas furnace regulated to produce steady temperatures. When the temperature is steady we may assume that the mean temperatures ot the two wires are accurately the same. The simultaneous resistances are measured by the Wheatstone bridge method with a sensitive mirror galvanometer and resistance boxes accurate to 0°01 per cent. The comparison of two similar pure platinum wires might be effected with even greater accuracy than 0°01 per cent. by using a wire bridge (Carey Foster’s method), since the ratio of their resistance is very nearly constant (variation perhaps 2 per cent. between 0° and 600°), and all sources of error affect both wires equally. The resistance of the connecting wires at each steady temperature is measured and allowed for, and thermoelectric effects are carefully eliminated : as a precaution the insulation is also measured. It is evident then that by adopting one wire as the standard and comparing others with it, temperature measurements may be made strictly comparable through a very wide range, since the platinum thermometer is almost universally applicable, and is usually more convenient, sensitive, and accurate than any other kind. The chief objection to its use is the need of auxiliary apparatus for accurately measuring the resistance: its great superiority lies in 1ts wide range, its freedom from zero error, and its adaptability. A length of wire is may differ 3 per cent., yet the values of * See article by W. N. Shaw, “ Pyrometers,’”’ ‘Encycl. Brit., 9th Edit., vol. 20, p. 129. On the Practical Measurements of Temperature. 233 cut off and disposed in whatever way is most suitable to the require- ments of the particular experiment. Comparisons were also made between the platinum pyrometer and the air thermometer at constant mass and volume up to nearly 600° C. By enclosing the fine platinum spiral inside the bulb of the air thermometer itself, errors of unequal heating were to a great extent avoided. A modified form of air thermometer was devised for the purpose, in which the air is confined at constant volume by sul- phuric acid in an auxiliary gauge which is connected to the mercury manometer by vulcanised rubber tube. For the high temperature observations the bulb was made of a combustion glass tubing which does not soften till 700° C.; the linear expansion of this kind of glass was determined by a very accurate method, in which the mean temperature of the glass tube is given by a platinum wire extending down its axis. It was found that if kept for any time at about 500° C., or higher, the glass bulb is lable to capricious changes of volume amounting to about 0'l per cent. or more; by a slight and convenient modification of the sulphuric acid gauge such changes may be determined on the principle of the volumometer and allowed for. By avoiding the permanent change the linear expansion could be represented by the formula + =1+ 00000680 bad «LO c2, wake 0 a mean error of 0°2 per cent. per single observation. Among other sources of error affecting the air thermometer at these temperatures we may mention surface condensation. It seems certain that the surface air film varies with the temperature, and when completely removed by exhaustion at a high temperature does not recover its normal state for some time, so that the zero pressure may decrease upwards of a millimetre of mercury in a week. The investigation of this is, however, still incomplete. . The results of all the observations with three different instruments are well! represented by the formula at re sren meee Sale sl shen SF where ¢ is temperature Centigrade by air thermometer, and the values of the constants are a=0 °0034259, B=0 0015290. Between 0° and 200° C. the curve (e) is very nearly a straight line, ~ R=1+0-003460¢, as it has a point of inflexion at about 80° C. The mean deviation of an observation between 400° and 600° from this curve is about 2°5° C., but it would be rash to use the formula (e) outside the range covered by the experiments: it is for all reasons far 234. Me TE Oallendee R —R, preferable to use t= 100, and to call the temperature so R, — Ry . calculated temperature by platinum wire, as this involves no assump- tion and different wires nearly agree. It is from athermometric point of view that the method above described of comparing different wires with the standard is most valuable: but it might also be em- ployed to form very accurate comparative tables of the change of resistance with temperature for different metals referred to platinum as a standard. Such tables would, however, be of little use apart from the actual specimens of metal employed, except in so far as they tended to elucidate the general phenomenon of the variation of resistance with temperature. With this view a comparison was made between platinum and iron, the resistance variation of which metal appeared likely from previous observations to differ widely from that of platinum. The curve deduced resembled the steam pressure curve, and suggested the formula* al Rage °c A formula of the same type was found to satisfy the air thermometer observations for platinum better than any other. The corresponding differential equation is . he (logR)“!= 0. If R,, Ry be any two observed resistances of the platinum coil, and dashed letters express corresponding quantities at the same temperatures for iron, we have a a oe. _B-p __ Coal gal a log R, logR’, loge logR, log R%’ ratures. ‘The comparison observations are tested. and found to satisfy this equation of condition; from which we may deduce the ratios a:a':(8—f'). Assuming the values of « and 6 for platinum to be a—0°0034259, B=0-0015290, we find for iron the values 2’ =0°0045657, G= 00007767. | The following table containing some of the observations taken by this method, with the temperature varying, shows the capabilities of the method and the sensitiveness of the platinum spiral. The time observations show the rate of variation of the tempra- ture. The resistance calculated by formula (a) B =1-+0:0034604, 0 shows the extent of the deviation from the straight line. The difference column shows how nearly the observations agree with formula (e), and the smallness of the probable error of a single observation. by equating tempe- from (e), * Reenault, ‘ Paris, Acad. Sci. Mém.,’ vol. 21, 1847, p. 619. 235 €T- 0 F000-0- — G696- T OFL6: T 6696-1 G- 186 i) CONE aera 00-0 0000. 0 + 0200: @ 6S10-% 0200-6 9- 66 & GL &T S €1-0 7000-0 E1Z0-2 9980-2 110-2 9. 662 oO a BI = 60: 0 T000. 0 + L080: @ 9660-% 9080-6 8-416 WAS = UIE ek a 9T-0 000: 0— 8660-2 S061 +6 SOOT: @ 8: &G& eg TL OT & . = €T-0 F000: 0—- CEGI-G O8VI- 3 6EEL-Z 8-T&& 67 II 6 S % 60-0 1000: 0 + {6ET-G 6Z9L-6 POSL-% T: 968 Ly It 8 =~ s 60-0 1000-0 — GOVI-@ EEL41-6 S6PT- ZG T: 6&8 {op IT L Se) S &T-0 7000-0 + G6ST-G LV8I-@ T6S1.-@ V-Gvs Vy LE a a) < 90-0 6000: 0 + TILT -3 CL6I1-& 6OLT. G 0. 9F& ev Tt g ae 9T- 0 ¢000- 0 + S6LT- Z 6906 -é 8841-3 9. SVE 6€ IT v a : “ULUL “SAT So 2a Ses ae eed ee Exerackes see ee fol > "LOLIO “JUD Ry eoieap tty *suULO UT (a) (‘») = *poArosqo *19JOUMOULIYY -TOTywA.T8q0 : s — onyea ae £q “yudD “OU, 70 ‘ON S QoULISISAT PIATOSqO "eB [NUULOT . RU ae ats ernyesodura J, pue (a) weeMgoq souo10 I(T eorrdue Lq poye[nopvo oouRysIsoy sc es ee lee A SEE Mr. H. L. Callendar. 236 —10.0 —10-0 -FT.0 —81-0 + 60-0 + 11-0 +0Z-0 To) +T1-0 + 60-0 —cT.0 —OT-0 0 0) +PFL-O + 10-0 0 0) See ee aa JO sooadop ur possord xa ur possoadxqy "poqyenoyeo pur | poeAtesqo WseMJoq SeoueLETICT 9290-4 9990. 4 V1E0-§ G- SPIT T- 48S 6-OV9 $116.9 4996-9 OV88- 3 VT: 866 G- PPS 6.98% CVE8 -T 96€8 -7 8SPSg.@ 0-964 Vv: OPV 6- OLP 9899. & STL49.€ 6866: & V- 90g 0. S96 T-V9E L99L-6 G69L-6 0666. T P- SEE g- 992 G- 696 LS00-@ 9600. @ : 0669. T 6-061 G- ELT §- SLT 696%. T 986%. T Sore -T 64. 66 6L. 66 64- 66 PELT- 1 GELT- T Gecl-T 8.68 TV. SS LG. Gs 1 1 1 Q Q Q 80 re NT SO] ‘UO1T WNUYV ‘OOT fat. L)\OOT a“ = 109 9 io (a) uorenbe fq (0) vpuutoy | (m) BpwuAog ot cope Pe Ue wee ‘poatosqo sured snosmez[Na1ig one woe Se are Ag ") .0 78 T 09 poonpoed sooueystsoyy ‘quog, sinyerodutay, ‘MOL, pus tanUYye[g jo uostavdwmoy JHE SME b 200 On the Practical Measurements of Temperature. — — T I T 06-% 098200. 0 PZS66-0 1290: T 0¢90-T €8.Z Z92E00-0 96966. 0 99IT- I OOZL-T 81.2 P9SEOO- 0 68Z66- 0 PEs. T 62ST €9-% 69800. 0 0686. 6 CGE. OOLT-Z €9.% 69800. 0 09286: 0 0628-2 0086. Z ‘097 200-0= : ae queqstoo ‘odIM porvdimog | ‘orm paepueyg prepueys ; Jed sytueroygeco eres SOOULISISOT JO Uvoul in Wusesog | See IO OUCH jo souereyiggy =| * PUB O yeh : S}WeLOqJa00 UBITL "poatosqo sated snoeweqnutg ",0 38 [ 0} poonpet soouvysisoyy ‘SOITAA WUnUAe[G Jo uostuedu0\g SHOE STEN b 6g-0— 94-0—- ‘apeVasIywIA seeidop UI SOUELOTIC, oT Sst ale 7a (») epnutao; OTT poredutoa kg ny (2) eMuULLoZ OTTAA paepueys Lg ‘epeisyuen ornqyerodwmoy, = ra bt I Oo = 238 Prof. T. Carnelley and Mr. W. Mackie. The chief difficulty of the comparison is that of protecting the iron wire from alteration when it is maintained at a red heat for some time. The following Table, II, gives some observations selected at random from a long series in which the zero variation of the iron did not exceed 0:05 per cent. The observations were mostly taken on different days; and the resistances observed at the air temperature in the intervals show the direction in which the correction for zero variation should be applied, but not its amount. It is noteworthy that in all cases the correction for this would tend to reduce the small differences between the formula (e) and the observations. As it is, the mean difference is only 0°1 C. Tt does not appear that any other equally simple and convenient formula could be found representing the observations equally well. Treating the observations on the comparison of two platinum wires in precisely the same way, we shail find for the values of the constants, assuming #3 as before for the standard wire— Standard wire « =0 ‘0034259. B =0 0015290 Compared wire a’=0 ‘0033382. B’=0 0015256 so that the values of B are almost identical. If B=f' we have the relation between the resistances at the same temperature CR | ETS Coe wee eae di de dese Ri, Ape ge! Tig! it is intended to continue the experiments at higher temperatures, and to apply the platinum thermometer to other investigations. “The Determination of Organic Matter in Air.” By Pro- fessor THos. CARNELLEY, D.Sc, and WM. MAcKIE, M.A., University College, Dundee. Communicated by Sir H. E. Roscog, F.R.S. Received June 10. Read June 10, 1886. The only methods hitherto proposed for determining the amount of organic matter in air are the two devised by the late Dr. Angus Smith (“‘ Air and Rain’’). According to the first of these methods, a defi- nite quantity of the air to be examined is slowly bubbled through a dilute solution of potassium permanganate of known strength until it is fully or considerably bleached, and in the latter case the amount of undecomposed permanganate determined by oxalic acid. In the second method a known volume of air is bubbled through distilled water, and the latter examined for free and albuminoid ammonia by Wanklyn and Chapman’s process for water analysis. The Determination of Organic Matter in Air. 239 These methods are open to one or more of the following objec- tions :— 1. The time required for a single determination is very considerable, and recessarily varies with the amount of organic matter present. 2. There is great uncertainty as to whether the organic matter has been fully absorbed and acted on by the permanganate in the first method, or absorbed by the water in the second. 3. It is difficult to determine the exact point of full bleaching, or to estimate by oxalic acid very small degrees of partial bleaching. 4. The methods are inapplicable (chiefly on the score of time and of the extent and complication of the apparatus required) in circum- stances and places where such determinations are most desirable. Analyses, especially by the second method, cannot be completed on the spot, except in very rare cases, so that unless a large quantity of apparatus be taken, several consecutive determinations in a series of buildings or rooms is impossible (cf. De Chaumont, ‘ Roy. Soc. Proc.,’ vol. 23, 1875). 5. The results obtained by the method proposed below show that very considerable variations in the organic matter are sometimes liable to occur within the period of determination required by Dr. Angus Smith’s method. By the new process, which it is the object of the present paper to describe, the above difficulties are in a great measure overcome. The special advantages we claim for it are:—(1.) Rapidity and simplicity of execution. (2.) A higher probability, though not absolute cer- tainty, that the organic matter is fully absorbed. (38.) A more general applicability. The principle of the process is the same as that of Angus Smith’s first method, viz., reduction of potassium permanganate. It differs, however, from Smith’s method, more particularly in the mode of estimating the amount of reduction. This consists in determining colorimetrically, by comparison with a standard, the fractional bleach- ing effected in a given volume of air. N : | 1000 strength, of which 1 c.c. = 0:008 mgrm. of oxygen = 0:0000056 litre of oxygen at Method.—The solution of permanganate used is of O° and 760 mm. It is ‘usually kept of a strength, and diluted as required, about 50 c.c. of dilute sulphuric acid (1 to 6) being added to each litre of the weak solution. For the collection of the samples of air large well-stoppered jars of about 3°5 litres capacity are used. The jars are first rinsed out with a little standard permanganate, and when not in use some of the solu- _ tion is always left in them, so as to ensure complete cleanliness from any reducing substance. Before use the jars are drained, and the 240 Prof. T. Carnelley and Mr. W. Mackie. sample of air collected by pumping out the contained air with a small bellows, and allowing the air to be examined to flow in. 60c.c. of the standard permanganate are next run into the jar, which is then tightly stoppered and well shaken up for at least five minutes. 25¢c.c. of the permanganate are afterwards withdrawn by a pipette and placed in a glass cylinder holding about 200 ¢.c., 25 c.c. of the standard solution being placed in a similar cylinder for comparison. Both are next diluted up to about 150 c.c. with distilled water, and allowed to stand for ten minutes, after which the tints in the two cylinders are com- pared. Standard solution is then run in from a burette, until the tints in both cylinders are of the same intensity; usually from 3% to 6 cc. are required. The amount of solution added from the burette is a measure of the bleaching effected by the known volume of air on half the perman- ganate employed. This multiplied by 2 gives the total bleaching. The results may be expressed either in terms of the number of c.c. of the = 7 bleached by 1 litre of air,‘or, as we prefer, by the number of volumes of oxygen required to oxidise the organic matter in, say, 1,000,000 volumes of air; e.g., 25 c.c. of solution from a 3° litre jar, in which 50 c.c. had been used, required 3 c.c. of the permanganate to bring it up to the standard, or the whole 50 c.c. would have required 3xX2=6c.c. This represents the number of c.c. of standard perman- ganate bleached by 3500—50=3450 c.c. of air; consequently Es 1:74 cc. is the bleaching effected by 1 litre of air. But 1 c.c. of KMn0O,=0:0000056 litre of oxygen; .*. 1°74 ¢c.c. KMn0,=0-0000056 x 1°74=0:0000097 litre of oxygen is required to oxidise the organic matter in 1 litre of air, or 9°7 volumes of oxygen to oxidise the organic matter in 1,000,000 volumes of air. Correction for temperature was not considered necessary, as it falls within the limits of experimental error. It requires about twenty minutes to collect the samples and complete the analysis. Scrupulous cleanliness is, of course, necessary in all the operations. We have examined many hundreds of samples of air by this method, | and in this large experience of it have found it to be a very con- venient and ready process. We believe it to be as accurate as is possible in the present state of the knowledge of this subject. Dupli- cate analyses of the same air give very concordant results, as evidenced by the examples given below. We are nevertheless fully conscious that objections may be taken to the method on the following grounds: —(1.) That it does not directly estimate the organic matter, but only measures the amount of oxygen required to oxidise either the whole, or more probably only a portion of it. (2.) That the permanganate acts upon various matters in the air, besides the organic matter, The Determination of Organic Matter in Air, 241 such as sulphuretted hydrogen, nitrous acid, sulphurous acid, &c. _(3.) That the organic matter in air is of various kinds, and that con- sequently the permanganate will most probably be selective in its action. Our knowledge on this point, however, is so defective that no definite conclusion is possible in regard to it. (4.) There is no satistactory means of checking the results, the only method being to make duplicate determinations of the same air. This test, such as it is, the method stands extremely well, as will be seen from the results given below, which are taken quite promiscuously from a large number of examples :— Organic Matter. Vol. of O required to oxidise the O.M.in 1,000,000 vols. of alr, 1st 2nd Determi- | Determi- | Mean. | nation. nation. Outside air (Dundee) 9°0 8:9 8°95 | Immediately after rain. a Fe 12°9 11°5 11°85 | No rain during day. as 10°0 10°2 10°1 Heavy rain, with wind. _ fe 8°6 8:1 8°35 | Rain shortly before. 5 (Perth) .. 2°0 1°6 1°8 Strong wind and rain. 4 i 2-0 1:5 1°75 { ye wind, rain at in- ervals. = 45 2°4 2°0 2°2 Storm shortly before. - Fs 4°8 46 4:7 Fine. rail ' ; : oy Unoceupied, but just | Class room (Dundee) | 10°5 8°8 9 65 er ‘ after dusting. me (Perth) .. 7°6 es Of 0 29 present for one hour. ey) ” 4 °O 5°0 4°5 31 ” 9 4 Unoccupied, but with Smallroom | s.0. 5 : A : 3 F 5 7. BLS November 25, 1886. I, Additional Evidence of the Affinities of the Extinct -Marsupial - ee Thylacoleo carnifex, Ow. By Sir Ricuarp Owen, K.C.B., E.RS. ‘ F : : ‘ . Z . : 1 oS II. On the Structure and Life- -History of Entyloma ranunculi (Bonorden). By H. MarsHatt Warp, M.A., E.L.S., Fellow of Christ’s College, Cambridge, and Professor of ie in the Forestry School, Royal ou Indian Engineering College, Cooper’s Hill . : : : og) coke III. On Jacobi’s Figure of Equilibrium for a Rotating Mass of Fluid. By . G. H. Darwin, M.A., LL.D., F.R.S., Fellow of Trinity College and Plumian Professor in the dee of Cambridge : : 0 | One - On the Dynamical Theory of the Tides of Long Period. By G. H. Darwin, LL.D., F.R.S., Fellow of Trinity College and Plumian Professor in the University of Cambridge . , : ° : : For continuation of Contents see 4th page of Wrapper. Price Six Shillings. BDL IF LSIOIO e Part I, 1886, CoNTENTS. I. A Memoir on the Theory of Mathematical Form. By A. B. Kemps, M. A. E.R. II. On Evaporation and Dissociation.—Part I. By Professor W1nli1AM RAMSAY, ‘ Ph.D., and Sypnry Youne, D.Se. III. On Evaporation and Dissociation.—Part II. A Study of the Thermal © ' Properties of Alcohol. By Wittiam Ramsay, Ph.D., and Sypyey @ Youne, D.Sc. 3 TY. On the Theory of Lubrication and its Application to Mr. Beauchamp Tower's a Experiments, including an Experimental Determination of the Viscosity of Olive Oil. By Professor OsBorne Reynotps, LL.D., F.RS. E VY. Further Observations on.Enterochlorophyll and Allied Pigments. By C. A. 4 MacMouny, M.A., M.D. 3 VI. Researches on Myohzmatin and the Histohematins. By C. A. MacMouny, M.A., M.D. VII. An Experimental Investigation into the Form of the Wave-Surface of : Quartz. By Jamzs C. McConnet, B.A. f VIII. Description of Fossil Remains, including Foot-bones, of Megalania prisca.— = Part IV. By Sir Ricwagp Owen, K.C.B., F.R.S., &e. IX. Dynamo-Electric Machinery. By J. Hopxinson., M.A., D.Sc., F.R.S., and 3 E. .HOPKINSON, M.A., D.Se. Index to Part I. Price £1 8s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the — Transit of Venus Expeditions. Price £3. 4 Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, may be had of Triibner and Co., 57, Ludgate Hill, - The Determination of Organic Matter in Air. Q47 definite intervals the carbonic acid and organic matter present in the air of the room were determined, the analyses being made in the room itself so as to avoid opening the door. The room being un- provided with outside light, one gas jet was kept burning during the whole of the experiments, but the effect of this on the organic matter may be neglected, for, as previously shown, the combustion of coal gas does not appreciably increase the amount of organic matter. The results obtained are shown below :— Outside | After 20 | After 30 | After 60 | After 100 alr. minutes. | minutes. minutes. minutes. 2 CO, 3°8 11 °4 14:8 — — lst experiment O.M. 9°5 12-9 14.8 pee Nits é CO, oe ee al! 23 °°5 28 °2 2nd experiment O.M. a i 14, -2 15°9 17-0 J CO, a Se 17 °2 yA | 321 8rd experiment 4 © 4. vi 13°5 15 °7 20°3 Here it is seen that the amount of organic matter becomes greater as the period of vitiation increases, but very much less slowly, so that the increase in the quantity of organic matter is by no means pro- portional to the time. It also increases less rapidly than the carbonic acid. (8.) An atmosphere which has been entirely at rest for some time is found to contain less organic matter than it did previously. This is not necessarily entirely due to the settling down of the solid organic dust, but is probably due in part to oxidation. The statement made in ‘ Nature’ (vol. 33, 1886, p. 130), in an article on ventilation, to the effect that the organic matter in respired air increases part passu with, and is therefore estimated by the amount | of carbonic acid present, may be true when the average of a large number of determinations is taken, but is certainly very far frora being true in individual cases. At any rate the amount of carbonic acid is no certain index of the quantity of organic matter present in an atmosphere (see above). That air in which respiration has gone on for some time gives invariably a higher result than outside air at or about the same time is all that can be confidently affirmed. It should not be forgotten that the organic matter in air is most probably partly solid and partly gaseous. The solid obeying a different law than diffusion slowly settles down, whilst the gaseous part, unlike carbonic acid, is most likely an unstable compound or compounds, and readily undergoes oxidation. Hxperiments were made in regard to this, but they did not give decisive results. = YOU. XLI. S ON eb 248 Mr. J. Joly. “[Noy. 285 November 18, 1886. THE PRESIDENT in the Chair. In pursuance of the Statutes, notice of the ensuing Anniversary Meeting was given from the Chair. The Right Hon. Lord Thurlow was admitted into the Society. Professor Bonney, Sir James ‘Cockle, Mr. Preece, Dr. Rae, and Mr. Stainton, having been nominated by the President, were by ballot elected Auditors of the Treasurer’s accounts on the part of the Society. The Presents received were laid on the table, and thanks ordered| for them. | The following Papers were read :— I. “On the Method of Condensation in Calorimetry.” By J. JOLY, B.E., Assistant to the Professor of Civil Engineer- ing, Trinity College, Dublin. Communicated by Professor FITZGERALD, F.R.S. Received June 28, 1886. (Abstract. )* A substance at the initial temperature ¢,° of the atmosphere, suddenly immersed in a saturated vapour at the higher temperature t.°, abstracts from it a quantity of heat equal to WC(¢,° —4,), where C is the thermal capacity of the substance between the limits 4° and t,, and W its weight. There is then a weight w of the vapour precipitated, so that WC? —1t,°)= wr, d being the latent heat of the vapour. By the observation of the weights and the temperatures, either ¢ or » may be the unknowns sought from the equation. The method is, in short, applicable to the determination of the specific heat of a substance or the latent heat of a vapour. The paper contains an account of experiments illustrating the application of this method of condensation to the determination of the specific heats of substances. The condensation of steam is em- ployed, its latent heat being accurately known, and. its use affording * This paper is printed in full at p. 302. u a 1836.] On the Method of Condensation in Calorimetry. 249 a considerable range of temperature. Two forms of the apparatus employed are described. The calorimeter consists essentially of a vessel of thin metal in which the substance is suspended by a fine wire, the wire issuing through an aperture in the top of the vessel and reaching up to one arm of a balance. The vessel is so constructed that steam can be passed through it from a small boiler, displacing the air around the substance. . The substance rests on a light carrier of platinum wire provided with a little catchwater beneath to receive the drops of condensed water. The manipulation involved is very simple. The substance being placed onthe carrier which depends from the balance, is counterpoised. The calorimeter is then closed around it, the suspending wire passing freely through the aperture provided. This aperture is formed in an absorptive material (plaster of Paris), which ensures that it remains free of precipitated water. A thermometer reading to ;3, degree C. is inserted in the calorimeter, and allowed to remain with the substance for an interval sufficient to secure close equilibrium of temperature. The thermometer being read is removed, and the calorimeter suddenly placed in connexion with the boiler, which supplies a brisk current of steam and fills it immediately. It then remains to note the incre- ment of weight when the substance has finally attained the tempera- ture of the vapour. This stageis revealed in the persistent equilibrium of the balance. {#,° is observed directly by a thermometer inserted in the boiler, or deduced by noting the height of the barometer and seeking the corresponding temperature of saturated steam from Regnault’s tables. A correction is applied to the weight observed in experiment, necessitated by the difference of the weights of the dis- placement of the substance in air and in steam. In accurate experi- ments the value of \ is corrected according to Regnault’s formula for its true value at #3”. The method is convenient for the reasons that it involves no preparations as in Bunsen’s change of state method, no delicate > thermometry, and the calorimeter being roomy permits of bodies of various shapes and bulks being dealt with. The apparatus, too, is of a simple and durable nature. The experiments quoted in support of the method are (1) on the metallic elements, zinc; silver, lead, platinum, and aluminium. The results are in accord with those of Regnault, Bede, Mallett, &c. The degree of consistency between the experiments is greater than that attained in Regnault’s researches. (2) On pure water sealed in thin glass bulbs. The results agree closely with the values deduced from Regnault’s formula. (3) On mineral substances in various states of aggregation. It appears from these that the result is but little influenced. by the extent of surface exposed to the steam. The accuracy displayed by the method is explained on the probable 8 2 250 Mids Joly: [Nov. 18, supposition that the substance is throughout the period of heating coated with a film of water adiathermanous and the external surface of which may be considered as appreciably that of the steam. The danger then of radiation error, that is, of steam condensing elsewhere than at the surface of the substance, is small. Condensation, in short, may be considered as taking place by abstraction of the energy of the molecule on impact with the water film. II. “On the Specific Heats of Minerals.” By J. Jouy, B.E., Assistant to the Professor of Civil Engineering, Trinity College, Dublin. Communicated by Professor FITZGERALD, F.R.S. Received June 28, 1886. A number of experiments were made on minerals by the method of condensation, using the form of gravimetric calorimeter described in the beginning of the paper on calorimetry (p. 353). The con- densation of steam being in all cases employed, the values recorded are the mean specific heats between atmospheric temperatures ap- proximating to 12° C., and steam temperature, about 100° C. More exactly, the values recorded are the mean calorific capacities for a rise of one degree between the limits ¢, and ¢,, tabulated in each case. The specimens dealt with were chosen as good samples of the mineral free from visible impurities.* But before detailing the particulars of the experiments a few notes on the discriminative value and physical interest attached to this application of calorimetry may not be amiss.} It seems probable that the neglect of the use of the specific heat constant is to be ascribed to the difficulties besetting its determina- tion. Certainly if its determination was as easily effected as we effect the determination of the specific gravity of a body, there are on the other hand sufficient reasons to recommend its use as in general of more physical value and interest than the much used specific gravity. There are cases indeed where specific gravity, as it is possible to obtain it, is misleading, and where specific heat gives at ‘once valuable information on the probable chemical nature of the substance. Such cases would arise with bodies of loose vesicular or hollow structure. No misleading variations need be introduced into the thermal constant by mere conditions of volume. The method of condensation permits of the determination of this constant with very little experimental difficulty. On the whole the _* T have to thank Professor Sollas for the loan of useful specimens from the Museum of Trinity College. ' + In November, 1883, I suggested this use of calorimetry to the Experimental Science Association, Trinity College-—‘‘ On the Determination of Minerals by their Specific Heats.” 18386.] On the Specific Heats of Minerals. 251 process is involved with no more liability to error than the process of weighing a body in air and in water. If, however, accuracy —greater than 1 per cent.—be desired, the operation takes con- siderably more time, as it is necessary, in securing ¢, accurately, to leave thermometer and specimen a sufficient time together in the calorimeter. The simplicity of the method is perhaps best in- ferred from the fact that of over 130 experiments on minerals there were but three spoiled—due to mishaps ; and it will be seen that the repetition experiments reveal in no case appreciable discrepancy. That this specific heat constant is very sensitive to the presence of impurities or variations in the chemical nature of the substance can- not be considered a disadvantage. It is supposable that this might lead occasionally to useful enquiry. This sensitiveness is shown in the case of tourmaline. Of three specimens the specific heats were— Hemihedral, black crystal ........ = 0°2000 Siriated, black evystal 2252... = 0°2008 Hemihedral, brown crystal ......-. == (A. The same, a second experiment.... = 0°2112 The variation from the black to the brown is over 5 per cent. Now tourmaline experiences considerable variations in the two con- stituents iron and magnesium. Approximately in percentage com- position according to Dana’s table of analyses— FeO. Fe,03. MgO. Black tourmaline contains.... 6 8 1 Brown tourmaline ae vrs th O) 1 11 which in view of the high molecular heat of magnessia and the low molecular heats of the oxides of iron would account for the differences in the experiments. It will be seen later in the particulars of these experiments that the densities of these crystals also, in a less degree, reveal the difference in composition. Again attention is suggestively drawn by the thermal constant to the chemical compositions of the first two of these three aerolites from the Museum of Trinity College. (1.) Fell in Co. Limerick, September 10th, 1813...... 01787 (2.) Fell in Maryland, U.S.A., February 10th, 1825.... 0°1785 io eiian Spain, daly Sth 1S eo es le Ske 0°1856 The specific gravities, too, of the first couple, are found to be identical, thus: (1) =3°604; (2) =3°601; (38) =3°435. The experi- ments, in fact, evidently afford strong reasons for believing that the first two aerolites constitute a case of the strange similarity ailuded to by Daubrée :—“‘Il y a des météorites éloignées au double point de 252 Mr. J. Joly. [Nov. 18, vue géographique et chronologique qui présentent parfois l’identité la plus complete, de telle sorte qu’il est impossible d’en distinguer les échantillons respectifs.”* He adds a list of the few such occurrences known. It is an important feature that the value of the thermal constant admits of being approximately, sometimes closely, calculated on an assumed chemical composition, and thus can be used in identification where comparative data do not exist or are not at hand. This fact rests on the experimental basis that the specific heat of the atom is preserved nearly constant through various atomic groupings. This applies indeed, only so far as the specific heats of the elements have been determined in the solid state; when the generalisation is applied to molecules containing elements whose specific heats as solids have never been directly determined it ceases to be accurate, and it appears at present as if in each kind of grouping a particular thermal capacity must be assigned to the atom. Approximate values of these thermal capacities have, however, been calculated by Kopp and others, and thus it is possible in all cases to pronounce for or against an hypothesis as to the nature of a substance, and this not alone in the case of simple salts, but when dealing with the silicates where many different kinds of atoms are present. In the case of the bisilicate beryl, for example, the most probable formula is 5BeO,2A1,03,H,O0,11Si0,.¢ Of these molecules the specific heat of BeO has alone not been directly determined. We take for the specific heat of Be 0°4380,f and taking the atomic heat of solid oxygen as 4°5—the value it affords approximately in com- pounds having the constitution RO§—we assume its sp. h. in the molecule to be 0°281. On these assumptions the sp. h. of BeO would be 0335. The atomic weight of Be is taken as 91. Taking advantage, then, of direct determinations as far as possible, the data are, sp. h. of BeO 0°335, of Al,O, 0°198,|| of H,O 0°501,4 of Si0,, 0°188.** From these, by an equation similar to Woestyn’s—t}t WS = mW y8, + ngWys.+..-., where s,, S,, . . . are the specific heats of the several kinds of mole- cules as above; 7, W, %, Wa, . . . the numbers and atomic weight of * “Géologie Expérimentale, Constitution des Météorites,’ p. 507. + From Penfield’s result that the composition is Be;,A14,8i,,;034, ‘Nature,’ vol. 30, 1884, p. 378. The ratio is not quite bisilicate. Mr. Penfield thinks, however, that water should be included in the formula. ft 11° to 100°, Humpidge, ‘Roy. Soc. Proc.,’ vol. 39, 1886, p. 8. § Kopp. || From my own results on corundum, agreeing with Regnault’s. § Person’s result, on ice, —20° to 0°. Landolt and Bornstein’s ‘Tabellen.’ ** My own result on quartz, agreeing with Neumann’s. t+ ‘Annales de Chimie,’ vol. 23, 1848, p. 295. 1886. | On the Specific Heats of Minerals. 253 each kind of molecule present in the substance; W the molecular weight of the entire compound = 2 wn; s the required specific heat _ —the sp. h. of beryl is found to be 0°2140. The experimental re- sults are ¢. Uramsparemt crystals .....2.... .. 0°2066 las Clompledi cry stalsis.). 3)... ae. 60 <6 0°2126 With the last variety the agreement is very close, but in either case the agreement is sufficient to render the calculation strong evidence had the case been one of hypothesis as to the nature of the sub- stance. } I proceed to quote a case where the identification of a mineral was in this way left to the calorimeter. The mineral had been assigued a place in a small collection as cryolite, on supposition. Its sp. h. was found to be 0°2558. This at once distinguished it from gypsum—sp. h. = 0°278—which it re- sembled in appearance. As I knew of no experiments on cryolite it was necessary to calculate the constant. The formula of cryolite— dNak + Al,F,—includes the sp. hs. of Na, F, and Al. Of these I’ has not been directly determined. Its probable value was deduced from the sp. h. of fluorspar, which I had found to be 0:2118. Ascribing to the calcium in this compound the value 0°170 (Bunsen), the sp. h. of fluorine is deduced as 0°251, which agrees with Kopp’s result. The other atoms in cryolite were assumed as follows: to the sodium was assigned Regnault’s value 0°293, to the aluminium that obtained by myself, 0°223. On these assumptions the calculated sp. h. of cryolite is 0°2569. The experiment on the hypothetical cryolite affording 0°2558, the diagnosis was assured. 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Altogether the evidence favours the conclusion that recently polished glass surfaces have a reflecting power differing not more than 1 or 2 per cent. from that given by Fresnel’s formula; but that after some months or years the reflection may fall off from 10 to 30 per cent., and that without any apparent tarnish. The question as to the cause of the falling off, I am not in a position to answer satisfactorily. Anything like a disintegration of the surface might be expected to reveal itself on close inspection, but nothing of this kind could be detected. A superficial layer of lower index, formed under atmospheric influence, even though no thicker than 754/995 inch, would explain a diminished reflection. Possibly a combined exami- nation of the lights reflected and transmitted by glass surfaces in various conditions would lead to a better understanding of the matter. If the superficial film act by diffusion or absorption, the transmitted light might be expected to fall off. On the other hand, the mere interposition of a transparent layer of intermediate index would entail as great an increase in the transmitted as falling off in the reflected light. There is evidently room here for much further investi- gation, but I must content myself with making these suggestions. Plate Glass Silvered Behind. This glass was silvered chemically by the milk-sugar process, and by transmitted light showed the sky of a normal deep blue colour. The film was not polished. In determining the efficiency of this and other good reflectors, the black glass mirror D’ was replaced by one silvered behind, The first trial without a revolving disk gave for the reflecting power 0°82. This result, of course, depended entirely upon the assumed influence of various obliquities of the adjusting plate. A disk was therefore prepared with two opposite projecting teeth, in which the ratio of aperture to circumference turned out on careful measurement to be 0°8230. This number, therefore, represents the transmission of light by the disk. Using this disk I found the follow- ing values for the reflecting power of the mirror for light incident upon it at an angle of 13° 52’ :— Asie s, ieee tet 0°823 Oe eM tet seh een des Beier 4 0°833 Meaity sy ivcic 6°828 This result relates, like all the others, to light polarised in the plane of incidence. Mirrors of this kind are durable, and not being exposed to tarnish are more convenient than specula, whenever the double reflection is not objectionable. The high reflecting power is a satis- factory feature. 1886.] Light reflected at nearly Perpendicular Incidence. 291 Silver-on-Glass Speculum. This was the silver side of the same glass as the last, polished with wash leather and a little rouge. The milky film was not perfectly removed. Four observations, not over concordant, probably in con- sequence of variation of reflecting power at different parts of the surface, gave— Lord Rayleigh. Mrs. Sidgwick. Mr. Gordon. met 6-902 .... Aug. 16.. 0938 ..... Aug. 14. 0-920 Pel... 0895 Mean. . 0°912. The surface was then repolished and remounted with the following results :— Lord Rayleigh. Mr. Gordon. meu Seo O98 ee eas AMG ou... O92 BO en iret Oreo) <7). sss are ee ae OO — BV olaa ite Mclsees O 950 Micame iiss) O94 eve es. Mean.... 0°934 Mean. . 0°939. The increase in efficiency may have been due to a more careful selection of the best polished central part as much as to actual improve- ment in the polish of the speculum as a whole. The transmission of the disk used with this surface is 0°9105. Sir John Conroy* found an even higher number (0°975) as the reflecting power of silver films for light polarised in the plane of reflection, and incident at 30°. Mirror of Black Glass. A plate of opaque glass has the advantage that the influence of the hinder surface is eliminated without more ado; but, on the other hand, it lends itself less readily to determinations of index, The following results were obtained with such a plate :— Mrs. Sidgwick. Lord Rayleigh. duly ZO. CeO aS eyes. — SOU are s ORO) ci] le Tae iA 0-0570 ousiNion) < WeOS88r LY elon. 0-0572 Bias Diets OOTTA GS enise as 0:0578 ee oe POSSE Wh byte: 0-0577 Mean... O CD80 4 ay a seid, 0:0574 Final mean. .0°0577. * ‘Roy. Soe. Proc.,’ vol. 37, 1884, p. 38. 292> | Lord Rayleigh. On the Intensity of — [Nov. 18, During these observations a disk was employed giving trans- mission 0°0577, so that in this case the final result is absolutely independent of the effect of the adjustable oblique plate. It will be observed that the separate results obtained by Mrs. Sidgwick and by myself differ, even in the means, by 1 per cent. This is not the only instance in which the errors have presented a suspiciously systematic appearance; but the differences being always small could not be sub- mitted to any satisfactory examination. It rarely happened, for instance, that Mrs. Sidgwick and I could find definite fault with each other’s settings. | When these results were first obtained, I thought that they would turn out to be too high for agreement with Fresnel’s formula, suppos- ing that the index of the glass was low. A subsequent measurement of “De specific gravity, however, gave reason for suspecting that the glass might be flint, a conclusion confirmed by determinations of the refractive index. These were made by two methods: (1) by observation of the polarising angle in air, (2) by observation of the angle at which total reflection sets in when the mirror is immersed in bisulphide of carbon. The first is, perhaps, the simpler in respect of experimental arrange- ments, but it is open to the objection that the inference of the refractive index from the polarising angle is somewhat theoretical. The black glass was mounted upon the turntable of an ordinary goniometer. In the focus of the collimator was placed a wire, seen dark in abright field of view. Various positions of the turntable were then tried, such that on rotating a Nicol held at the eye the dark patch appeared to pass somewhat to the right or to the left of the collimator wire. After each observation the web of the telescope was set to coincidence with the collimator wire, and a reading taken. Success depends in some degree upon the use of a suitable light. Sunshine diffused through ground glass answered the purpose very well. Right. Left. Central. 64° 25’ chaos 63° 56’ ee 64° 7! 16 aielete 40 plete 64 0 a7 a5 las D0 cae == 14 leks 50 ris deus = The table gives a set of circle readings. In the first column the patch was to the right of the collimator wire, in the second to the left, and in the third there was no appreciable deviation. We may, therefore, take as the reading for the polarising angle 64° 5’, with a probable error not exceeding 3’ or 4’. The reading for a direct setting of the telescope upon the collimator wire was —95’, so that the polarising angle is $(180—64° 10')=57° 55’. Whence according to Brewster’s law— 1886.] Light reflected at nearly Perpendicular Incidence. 293 ji Se OY os SUN This relates to white light. To find the index of refraction by the method of total reflection, the mirror was mounted vertically in a small tank of plate glass, cemented with glue and treacle, and containing bisulphide of carbon. The mirror H, as shown in fig. 2, was parallel to one of the sides of Fria. 2. the tank, and a cover was provided to check evaporation. A uniform field of homogeneous light could be obtained from a salted spirit lamp, A, with the aid of a plate of ground glass, B, and a collimating lens, C. The eye looking in along such directions as GF, is able to mark with considerable accuracy the direction in which total reflec- tion begins. By the aid of plumb-lines, &c., this direction and that of the face of the mirror (seen from above) were marked upon a board, and it appeared that the angle GLK, between the face of the mirror and the direction GULF of the first totally reflected emergent light was 18°. A beautiful variation in the experiment may be made by replacing the spirit lamp with a candle, and subsequently analysing the reflected light by a direct vision prism. For this purpose a screen carrying a slit should be interposed as near F as conveniently may be. As the incidence of the light upon the black glass becomes more grazing total reflection sets in, but first at the violet end of the spectrum. 294 Mr. J. Brown. [Nov. 18, When the eye is looking nearly in the right direction, the spectrum appears to be covered by a veil proceeding from the red end up toa point dependent upon the precise direction of the light. By slightly shifting the eye, the veil may be made to reach any desired part of the spectrum, and then we know for what ray total reflection is just commencing. By bringing the veil to touch the soda line (rendered visible with the aid of the spirit lamp), precisely the same direction was found as had previously been marked out with use of homo- geneous light. It would be possible in this way to determine with considerable accuracy the dispersive powers of opaque bodies. The angle of 18°, , being measured in air, is not the complement of the true angle of rofldenie al If we take 1:630 as the index of CS, for soda light, we find for this angle ee / Sit Se Winey a )=10 car whence for the index of the glass relative to soda light, p =1°680 cos 10° 56’=1°600. The amount of reflection according to Fresnel’s formula, with an incidence of 13° 52' and an index 1°600, is 0°05726, a little Jess than that actually observed. The agreement is as good as could be expected, but it should be noticed that this mirror was merely cleaned and not repolished with putty powder. If repolishing were to produce as much effect in this case as upon the acute-angled prism (1), Fresnel’s formula would be left consider ably 1 in arrear.* P.S. Nov. 9, 1886: oy am indebted to Mr. Glazebrook for a deter- mination of the refractive index of the prism of crown glass II]. He finds » = 15328. The introduction of this into Fresnel’s formula (9 = 18° 52’) gives for the reflecting power 0°0477, V. “A Theory of Voltaic Action.” By J. Brown. Communi- cated by Lord RayYueIcn, Sec. R.S. Received October 4, 1886. [Puates 4 anp 5.] 1. From a series of experiments made more or less continuously during the last five years the following conclusions have been drawn :— That the difference of potential near two metals in contact as observed either by the bi-metallic condenser (Volta’s) method, * Some of the results here given were communicated to the British Association at Birmingham, where also was read a paper by Sir John Conroy on the same subject, Proc.Roy. Soc Vol4H.PU.3. Mirror outside of window. Si en ee haatter. Ground glass. Shutter. | | | if ' Tron Sur tauce Plate. Seale = 12 WestNewman &Co. sc. (oe ~ 1886.) A Theory of Voltaic Action. 295 or by the bi-metallic ring or quadrants method of Sir William Thomson, is due to the chemical action of a film of condensed vapour or gas on the surfaces of the metals.* That the two metals with their liquid or quasi-liquid films are quite similar to a galvanic cell composed of the same metals as elements, and a liquid similar to that of the films as electrolyte ; the said electrolyte being (in the ordinary static “contact” ex- periment) divided by the intervening insulating diaphragm of air or other gas. 2. Therefore in these experiments it is the difference of potential at the outer surfaces of the two films that is measured. In the case of a single metal, e.g., zinc covered by its chemically active electrolytic film, there is, according to the view here advocated, at the surface of contact between the film and the metal, an electro- ‘motive force due to the chemical action between them, charging the zinc negatively and the film positively. The two charges being bound have no outer manifestation of any kind. Copper again, for example, is affected similarly, but less strongly, than zinc. If it be connected metallically to the zinc, the potentials of the metals will be equalised, a portion of the negative charge going through the connexion from the zinc to the copper and thence to the film on the copper. 3. This theory as applied to the Volta condenser experiment is referred to somewhat in detail by Wiedemann (‘ Die Lehre von der Hlektricitat,’ vol. 2, pp. 986—987); and the view held by De la Rive (‘ Traité de l’Electricité,’ vol. 2, 1856, p. 776) was very similar, differ- ing mainly in the supposition that the positive charge separated off in the film was maintained there by the insulating nature of the film whereas it is evident that an electromotive force at the surface of contact of the film with the metal sufficient to cause the separation _ of the two charges will also be sufficient to keep them separate. We are, therefore, in so far not debarred from considering the film an electrolytic conductor. De la Rive’s view seems, however, to have received little general attention, perhaps less than it deserved. 4. It seems advisable to discuss these views experimentally while trenching as little as possible on the uncertain domain of. speculative molecular physics, and in describing the experiments [I shall refer in detail to those only which gave reliable results. Many preliminary trials were made before disturbing causes were eliminated, and many negative results were obtained. It has, however, been gratifying to find that no reason has appeared requiring the alteration of anything in the two short papers previously published on this subject (‘ Phil. Mag.,’ Aug., 1878, Feb., 1879). %* (No account is here taken of any infinitesimal effects that may be due to thermo-electric action, &c.—December 3, 1886. ] VOL. XLI, X Se ee 296 Mr. J. Brown. [Nov. 18, 5. The principal piece of apparatus used was a _ bi-metallic quadrant electrometer represented at fig. 1, about one-fourth actual size. Its design was an elaboration of the temporary apparatus described in a previous paper (‘ Phil. Mag.,’ vol. 2, 1878, p. 142). A is a metal case supported on levelling screws; B a thick vulcanite tube provided at its upper end with a brass cap containing a collar of leather in which slides the brass rod C. D is a brass ball with clamping screw to retain the rod at any desired height. E is a platinum torsion wire, 0°00] inch diameter, carrying the stouter wire F, on which are fixed a light concave mirror G, the ‘‘ needle” H, and a glass weight J dipping in water or other liquid contained in a glass vessel, resting on a vulcanite plate on the bottom of. the instrument. R and L are the quadrants of the metals under examination screwed to a vulcanite piece M which is adjusted by hole, slot, and plane on the points of three long fine-threaded levelling screws, O, P, Q, passing up through stuffing-boxes in the bottom of the instrument. The quadrant L is connected to an insulated wire N passing out air- tight through the back of the case. R is connected to the body of the instrument and to “earth” by aslip of foil under the vulcanite support touching the screw O. A _ stopcock T in the top of the vulcanite tube and another in the bottom of the instrument of which the opening is shown at 8, provided means for varying the nature of the gas surrounding the metals. The opening in front of the instru- ment was provided with a flange, faced up to a plane, on which a pane of plate glass was jointed by grease or other suitable means. The needle was electrified either positively or negatively by connecting its suspending wire through a Pohl’s reversing commutator to either pole of a battery of 100 small Daniell cells: the opposite pole being at the same time connected to the body of the electrometer and to “earth,” 6. To make an experiment with this apparatus the quadrants were first carefully adjusted with their upper surfaces in the same plane, then put in position, roughly levelled, the connexion to wire N made, and the pair dusted with a camel-hair brush. The needle which had been raised by the sliding-rod C was now lowered to within about 0:05 inch of the surface of the quadrants, and adjusted with its centre line over the slit between them and its suspension wire in the centre of the system. If now on connecting the quadrants metallically, and electrifying the needle positively and then negatively, it was found that the | deflection (as observed by lamp and scale) was greater on one side of ~ zero than on the other, due to one quadrant being higher than the ~ other, the necessary adjustment was made by means of the screws O vi and P. A second concave mirror fixed on the ball D was now e| clamped, so that its reflected beam also fell on the zero of the scale, A 1886,] A Theory of Voltaic Action. 297 so that after raising the rod C it could be readily brought back to its original position. The quadrants were now levelled by a spirit-level from front to back, after which the difference of potential might be at once taken, or they might be removed again to be cleaned, rapidly replaced, and a reading taken as quickly as possible afterwards with- out the loss of time in adjusting them. A ‘‘reading’”’ was taken by causing the needle (by reversing its potential twice) to deflect first on one side (say right) of zero, then to the left, and again to the right. The mean of the two right-hand deflections was added to the left-hand one in order to eliminate the effect of a slow shifting of the zero which sometimes occurred, caused apparently by a slow untwisting of the suspension wire, or a slight warping of the vulcanite piece M. 7. The readings were either qualitative when the two quadrants were put in metallic connexion, or quantitative when the difference of potential of their films was compared with a standard cell. In order to make the connexions conveniently for both kinds of readings a modified Pohl’s commutator was used, by means of which the quadrants could either be directly connected with each other, or else one to each pole of the standard cell W in either sense. 8. At first two standard cells were used, a Clark’s cell purchased from Hlliot Brothers, and a Daniell constructed asat W. X, Y, Z are three test-tubes fixed in a block of paraffin. X contains a half- saturated solution of zine sulphate, with a rod of redistilled zinc not amalgamated. In Z is a gutta-percha covered copper wire, having its lower end cleaned, wound into a spiral, and covered with crystals of copper sulphate and water. Y contains distilled water with a strip of zinc to reduce any copper salt that might diffuse over from Z. When the Clark’s cell was used, the results were reduced to the Daniell as unit value. Comparisons with both cells were at first frequently made. 9. The measurement of the difference of potential near any pair of quadrants was made by a well-known method as follows. The cell was first connected, so that its electromotive force should increase the defiection due to the difference of potential near the quadrants, and a reading a taken. The connexion was then reversed, and a reading b taken. If d is the deflection due to the standard cell, and p that due to the difference of potential near the quadrants— d+p=a d—p=b therefore ee —. For example, in comparing the difference of potential of the films on slightly tarnished copper and zinc in air the following deflections were found— ' Dap 248 Mr. J. Brown. [Nov. 18, Copper of cell to zinc quadrant— Right, 76; left, 75; right, 74°5. a=150°25, Copper of cell to copper quadrant— Right 19° 55 left, 11°5; right, 20°5. b= 31°5. (ae p=0°'65 Daniell. Owing to the nature of the apparatus, extreme accuracy in the results as absolute quantitative measurements is not to be expected. They are meant in most cases more for comparisons among them- selves. 10. A number of experiments were made to ascertain the rate of decrease of difference of potential of the films on copper and zinc in air due to gradual tarnishing of the metals. The curves corresponding to two of these with zinc of different degrees of purity are given in fig. 2, where ordinates are in decimals of the electromotive force of one Daniell, and abscisse represent the time elapsed after cleaning the metals with glass paper. Ten more observations were made on the pair of copper and redistilled zinc giving curve A. The remainder of the curve has the same character, falling in 613 hours to 0-64 Daniell. | The object was to estimate the difference of potential due to the clean metals by carrying the curve back to the time at which they were cleaned, and compare this with the difference of their heats of combustion in oxygen as compared with the heat equivalent of the standard cell. The result agrees fairly well with the thermochemical data of J. Thomsen (‘ Wiedemann, Beiblatter,’ 1880, Nos. 7 and 8). We are met, however, with the fact that with many other pairs of metals in air we do not find the same agreement, although in most cases there is a more or less near approximation. This I believe is due to two causes :— (1.) We cannot tell the exact nade of the chemical process going on at the surface of the metals, whether it be simply an oxidation ; which particular oxide of the metal is formed, or if the other pire ammonia, carbonic acid, &c., take any part in the process, nor do we know exactly the physical state of the film. (2.) We do not know how much protective effect the pane formed coating of oxide, &c., exercises on the metals. 11. The comparatively Sel and often irregular difference of potential observed when experimenting with copper and iron may be due to the formation on the latter, immediately after cleaning, of a highly protective oxide coating, producing a more or less passive state analogous to that which this metal assumes under other well- known conditions. The rapid tarnishing of lead may also produce a similar effect supposing the oxide formed be of a very coherent and protective nature. 1836. | A Theory of Voltaic Action. 299 The consideration as to which oxide is formed leads to the question whether any difference of potential would be found near the contact of two different oxides of the same metal—I experimented on litharge and red lead, and on stannous and stannic oxides, but did not get results sufficiently definite to be reliable—but I think the experiments worth repeating with freshly-formed oxides, which mine were not. 12. It has been suggested in criticising my former experiments on the effect of various gases on the difference of potential near certain metals in contact, that it would have been better to have had quanti- tative results. Although for the reasons given above these are perhaps not of very much value, I have, however, made measurements in several cases. The following are the results with a copper-iron pair in hydrogen sulphide gas. Quadrants of these metals after being freshly cleaned with glass- paper were put in position, and the difference of potential in air measured as quickly as possible was found to be 0°059D, 0°062D, mean 0:06D, iron side positive. _ Hydrogen sulphide was now sent into the electrometer, reversing immediately the relative potentials near the metals. The stopcocks were then closed and the following measurements taken :—+ repre- senting the time elapsed after admission of the gas, and P/D the ratio of the difference of potential near the metals to that of the terminals of a Daniell cell. ; zt, 8m. 15 m. 25m. Lh.18m. 2h.10m. 2h. 35m. 12h. 10m. P/D. 0-4. 0-48 0°53 0°55 0°4:7 043° 03 Some fresh hydrogen sulphide now sent in caused a slight rise, P/D=0°32, after which it fell slowly, and im about 11 hours more (¢=23h. 25m.) it was 0°26. The instrument was now cleared of gs and left open for about 14 hours, when P/D fell to 0:1. Re-admiss.on of gas raised it to 0°32. This was repeated with the same result, after which the instrument was left open for 24 hours, when the iron side was found positive, P/D=0°32. This somewhat high value may be due to oxidation of the iron sulphide, but more probably perhaps to oxidation of the iron itself, coupled with the protective action of the very thick coating of sulphide on the copper. After again ad- mitting the gas the copper side became again positive, P/D=0 26D. Several more changes of the atmosphere were made, the corresponding change in difference of potential taking place each time. The electro- meter was then charged with the gas and closed up, the water vessel having been removed (so that its vapour might not interfere with insulation inside the instrument), and its place suppled by paper vanes cemented to the weight. The difference of potential then fell gradually till at the end of eight days after the gas had first acted on the metals it was sensibly zero. On opening the electrometer plenty 300 | Mr. J. Brown. [Nov. 18, of the hydrogen sulphide was found still present in it, and the metals were much corroded; the copper brown with lighter patches; the iron greyish with patches also, but having a thinner coating of sul- phide than the copper. On allowing the metals to remain exposed to: the air, the iron side became again gradually more positive; the difference of potential rising during 26 hours to 0°:26D, after which it fell in about a week to 0°22D. 18. As the electrochemical relation of silver and iron in water is also reversed when solution of potassium sulphide is added, I had little doubt that an addition of hydrogen sulphide to the air about these metals when in contact would reverse the potentials near them. To test this the upper surface of the copper quadrant used in the last experiment was covered with a piece of thin silver sheet cemented on, thus forming a silver-iron pair with the iron quadrant. The difference of potential just after cleaning the metals with emery- and glass-paper was 0°23D, iron side positive. In three minutes after admission of the gas the next ‘reading showed the silver side positive; difference about 0'4D. The following readings were then taken, t as before the time after admission of the gas. ih 12m. 16m. 1h.Om. 23h. 40 m. 33h. 30m. 58h. 40 m. P/D. 042 . 044 0:43 0°38 0°35 0°35 , 84h. 20m. 94h. | 0°365 0°38 The sulphide formed on the inside of the metal case of the instru- ment by the action of the:gas, now began to peel off in scales and jammed the vanes of the weight. After cleaning these out fresh gas was sent in, and P/D became 0°36D; silver side still positive: Measurements were then made at intervals, the difference of potential falling gradually to 0°23D, on the fourteenth day after admission of the gas at the outset. By that time, however, the gas was found to have been all or nearly all absorbed by combination with the metals and the sides of the instrument. The conclusion of the experiment is therefore in- complete, but it indicates that the difference of potential decreases with these metals also, although more slowly than with copper and iron. 14. It was suggested by Mr. Cross, of Barrow-in-Furness, that the difference of potential near a copper-iron pair in air and in ammonia gas should be compared. The electromotive force of a cell formed by these metals immersed in distilled water is about 0°35D, copper the positive pole, but if ammonia solution be added, this electromotive force reverses and becomes 0°27D. | Three experiments were made with copper-iron quadrants in this gas, which was sent. into the instrument by boiling strong lquor 1886.] | A Theory of Voltaic Action. 301 ammonie in a flask connected by glass tubing to the stopcock T. In each case the potential was reversed, and the difference of potential appeared rather less in the ammonia atmosphere than in air, but owing to the action of the gas on the vulcanite piece M, causing it to twist and so alter the position of the quadrants, I was unable to get reliable quantitative comparisons with the standard cell. _15. In a cell composed of copper and nickel in distilled water, nickel is the positive metal, and the electromotive force is about 0:24D. On adding a few drops of a solution of ammonia a reversal. takes place and copper becomes the positive metal. The electro- motive force appears at first rather greater than that of the water cell but falls off quickly. The analogous experiment with gaseous ammonia was made in a qualitative way only. The quadrants of the electrometer were re- placed by a flat ring half copper and half nickel, the two metals soldered together. (This had been used in a former experiment with hydrochloric acid gas.) The metals of the ring having been rubbed bright with emery- paper, the potential in air only near the nickel was positive to that near the copper, the index passing over about 45 divisions, when the electrification of the needle was reversed. After admitting ammonia gas in the same way as before describea the copper side became positive, at first slightly, but after two hours the index moved over six divisions for a reversal of the needle. Tha two kinds of experiments therefore agree here also fairly well. 16. I now sum up the results (regarded qualitatively only) ob- tained in this kind of experiment, where a change in the constituents of the atmosphere surrounding a pair of metals in contact reverses the difference of potential near them in correspondence with the reversal of electromotive force, which takes place after a similar change in the corresponding liquid electrolyte used with the same metals as a voltaic cell. a Compound whose addition Compound whose addition ag gas to the atmosphere in solution causes a reversal | surrounding the metals in of electromotive force in a | contact causes a reversal of hydvro-element or cell. the difference of potential observed near them. Pairs of metals. Copper-lron..... Potassium sulphide ......| Hydrogen sulphide. Copper RtOn. sae.) AMMOMG . 0.000600 yo nwess Ammonia. Silver-Iron......} Potassium sulphide....... Hydrogen sulphide. Copper-Nickel...| Ammonia...... ...s.| Ammonia. Copper-Nickel ...| Hydrochloric td ats Hydrochloric acid. 302 Mr. d. Browne | [Nov. 18, These are the only cases tried; no exception has, therefore, been found by me, nor, so far as I know, by others. 17. One of the most ingenious explanations (from the pure contact theory point of view) of the change of potentials near the copper- iron or copper-nickel pair effected by hydrogen sulphide or chloride is that of G. Wiedemann (‘ Lehre von der Hlectrikitat,’ vol.1, p. 205), who suggests that in addition to the films of sulphide or chloride formed on the metals, a film of hydrogen may be deposited, and the contact effect of all these substances is added to that of the metals. It may be pointed out that precisely the same explanation may be given of the usual experiments made in presence of water-vapour where the oxygen combining with the metal forms an oxide film, : which may again be covered with the hydrogen left free. 18. Several other authors have urged as an objection to these expe- riments, that the action of the gases causes the formation of coatings of various compounds, and so the whole state of things is altered by the introduction of additional bodies or substances assumed to intro- duce new so-called ‘contact effects.” (See Ayrton and Perry, ‘ Phil. Mag.,’ January, 1831, p. 48; Pellat, ‘ Journal de Physique,’ vol. 10, 1881, or ‘Theses présentées a la Faculté des Sciences de Paris,’ No. 461, p. 16.) : Dr. Lodge also states (‘Brit. Assoc. Report,’ 1884, p. 50), ‘‘ but satis- factory observation in these gases is difficult, because they not only tend to attack the plates, but they do attack them, and so a film is formed and everything is rendered uncertain.” But it is surely too much to say that no such film (of oxide) is formed in the experiments as usually made in air. We are even jus- tified in inferring that such a thing as a “contact”? experiment on clean metals has not yet been made, since they are invariably cleaned while exposed to the atmosphere, and therefore covered with a layer or film of highly condensed water-vapour containing other dissolved gases. Hach abrading point of the polishing material (emery, glass-paper, or whatever it be) may almost be said to be working under water on the metal. It seems difficult to suppose that even for an instant after each little abrading point has passed, the surface of the metal exposed in its track remains unoxidised. All such critics assume quite unwar- rantably that in the old contact experiments of Volta the surface of the plates is not altered by the atmosphere, whereas the alteration is not only after a time visible to the naked eye, but is accompanied by a sequence of electrical effects in a quite similar way to that when other gases are used, which attack chemically one or other of the metals, so as to mask or overpower the action of the oxidising atmosphere still present. On the other hand, when gases are added 1886. | A Theory of Voltaic Action. a0a that have not an action differing from that of the air (still present to a greater or less degree), or are merely neutral, there is no great difference in the electrical effects produced (Pellat, ‘Theses pré- sentées a Ja Faculté des Sciences de Paris,’ p. 109; Schulze-Berge, ‘Wiedemann, Annalen,’ vol. 12, 1881, p. 293). The effect of a hydro- gen atmosphere in gradually decreasing the negative potential near platinum is an exception, and has been already well explained. by the hypothesis that it. forms an alloy with the platinum of a more positive character; or which, according to the chemical theory, has a greater affinity for the oxygen still present than the platinum has. 19. Many attempts have been made to remove completely from the metals under examination all oxidising or other chemically active substances, and thus show that the metals per se have no power of producing a difference of potential. Some of the older writers claim to have effected this by thickly varnishing the plates of the copper-zinc Volta condenser. I doubt if even a thick coat of varnish, which is more or less pervious to gaseous matter, would so effectually protect the surfaces as to leave no effect discernible by the more sensitive modern appliances. JBesides, the varnish itself is objected to. as a new element in the chain of ‘ con- tact” effects. Some experiments on the effect of varnish were made with the large Volta condenser shown at fig. 3. 20. This instrument was in general form copied from that described by Schulze-Berge (‘ Wiedemann, Anualen,’ vol. 12, 1881, p. 294). Referring to fig. 3, A is a triangular piece of mahogany 1 inch thick, turning on pointed screws at B, and resting at its other end on a support M. Itcarries on its lower surface three vulcanite fittings, DD, supporting the copper plate C, which can thus be raised from or lowered towards the zinc plate Z, lying on three vulcanite levelling screws, SS. The plates were 8 inches diameter, and about ; inch thick. A measurement of the difference of potential of the films on these plates was made by a method similar to that employed by Schulze- Berge and shown at fig. 4, where D is a Daniell’s cell, of small internal resistance, connected to RR’, a set of resistance coils, of which the part a is 200 ohms and @ is. variable. The key K breaks the connexion of both the condenser plates Cu, Zn at once. In making an experiment the resistance 2 was adjusted till on breaking the contacts at K, and immediately afterwards separating the plates, no sensible deflection was observed at the quadrant electrometer E in connexion with them. Then the amount of resistance in x divided by the whole resistance RR’ gave in terms of the Daniell the difference of potential required to neutralise that of the films. 21. The zine plate of this condenser was carefully varnished all over while hot with repeated coats of “ silver lacquer” (shell-lac and other gums dissolved in spirits of wine), but the difference of 304 Mr. J. Brown. [Nov. 18, potential between the varnish on the zinc and the film on the opposed copper plate did not fall below 0°29D taken while the zinc was hot. On cooling for 15 minutes the value rose to 0°35D, and after some hours to 0°46D, an effect easily caused by the passage of moisture into the varnish. Fifteen hours after it had fallen to 0°'4D, in- dicating probably the formation of a partially protective coat of oxide under the varnish. The commonly accepted value for plates of these metals recently cleaned in air is about 0°8D. 22. I have also endeavoured to obtain this result, although without much hope of success, by immersing the platinum-zine quadrants of the electrometer, fig. 1, in naphtha which had been divested with metallic sodium for several mouths in order to free it if possible from oxidising matters. Metallic sodium was also placed on the bottom of the electrometer. The naphtha was contained in a glass jar, and connected by a syphon tothe stopcock 8. The difference of poten- tial of the polished metals measured in air was 0°38 D. The naphtha. was now run in for five minutes, when its level was about 0°05 inch over the surface of the quadrants, and about the same distance below the needle. The following observations were then made ; ¢ denoting time elapsed after the metals had become covered :-— t=8m. 40m. 1h: 40m. 2h. 40m, 4h. 7h. 12h. 22h. 066D G61D ~ 0-49D 05D 049D. O39D. 0O39D 0°31D. Two hours after this Jast observation the naphtha was partially run out of the instrument, so as to bring its surface below the level of the quadrants, when a measurement gave only 0:23D. It is difficult to see why the thin film of naphtha still present on the plates should possess a more protective power than the bulk of the liguid. . It may be that there was in the naphtha some small quantity of water or other substance chemically active towards the zine (the deterioration of sodium or potassium under naphtha is well known) which would soon become exhausted from the thin film, but the hypothesis is open to doubt. 23. Faraday considered that electrolytic ‘‘ decomposition and the transference of a current are so intimately connected that one cannot happen without the other” (‘ Exp. Res.,’ vol. 1, p. 252), I thiak it in the highest degree probable that the same theory applies to the production of the momentary current which gives rise to a difference of potential near the surfaces of two apparently dry metals when placed in contact, and that the electrolyte then active consists of the water supplied from the air and condensed in invisible films on them. Hence the chemical action producing the electrical effect is not only. 1886. ] A Theory of Voltaic Action. 305 the mere oxidation by free oxygen, but is associated with the decom- position of the condensed film on the metal. 24. The apparatus, fig. 1, was admittedly not sufficiently imper- vious to gaseous diffusion to permit of a crucial experiment on the effect of drying the atmosphere surrounding the metals. However, in the hope of partial success, the following experiment was begun in 1884. The copper and zinc quadrants were adjusted in position, the water vessel having been removed, and a weight with paper vanes substituted. The difference of potential was found 0°68D. Two small porcelain capsules containing phosphoric anhydride were placed inside the instrument, and the joint between the glass front and the metal facing made as good as possible with grease. The following measurements were then made in terms of standard Daniell; ¢ in this case standing for days after closing up the instrument. t=0 1 2 3 4) 7 9 11 13 P/D=064 062 064 O61 059 O89 #058 0°58 0°57 t=20 Sy 0 78 124, 134 304 305 P/D= 0°56 0°56 0°557 0°54 0°50 0°52 0°51 The phosphoric anbydride was now taken out, and the instrument, allowed to remain open for twenty minutes, after which a very care- fully made and satisfactory observation showed that the difference of potential had increased to 0°646D. Fresh phosphoric anhydride was now placed in the instrument, which was closed as before, and the value measured immediately afterwards found to be 0°659D. A similar series of observations was then made for a period of 173 days, during which the observed difference of potential fell more or less regularly to about 0'5D. Then on allowing the instrument to remain open for one hour it rose to about 0°67D. These results were quite as marked as I had hoped for with such unsuitabie appa- ratus, and seem to show very clearly that even a partial drying of the metallic surfaces alters the difference of potential near them in a decided manner. 25. In 1881 I had endeavoured to construct a copper-zinc quadrant electrometer hermetically sealed in a glass vessel, from which I could exhaust the air and absorb the oxygen compounds by potas- sium. Repeated failures in the construction of the apparatus have hitherto ‘debarred the experiment. A similar idea occurred to Herr Von Zahn about the same time (‘Untersuchungen iiber Contact- Hlektricitit,’ p. 48). He enclosed a platinum-zinc condenser in a hermetically sealed. tube, together with metallic sodium. The difference of potential was reduced in this case to about 0°5D, which the author attributes, in part at least, to the absence of moisture. He considers the experiment 306 SOME Browser) a [Nov. 18, would be a crucial one in favour of the chemical theory, if, after opening the tube, the difference of potential was found to have increased. He does not, however, open it. There are two objections to this particular experiment. The tube, &c., was washed out with water which tarnished the zine. The action of the sodium on moisture would evolve hydrogen, which would alloy with the platinum. The former would reduce the difference of potential permanently, and the latter perhaps temporarily, but neither would, I think, much aifect the conclusion to be drawn from a measurement made imme- diately on opening the tube. 26. Von Zahn also experimented qualitatively on the difference of potential between a copper plate and a flat spiral of glass tube con- taining sodium used as. a Volta condenser plate, but does not seem to. have tested the effect after the lapse of any considerable time, although he states that the surface of the sodium remained bright after standing some years. If Bunsen’s hypothesis (‘ Phil. Mag.,’ vol. 17, 1884, p. 172) that glass may gradually, year after year, absorb a part of the liquid film in contact with it, be true, it would probably be necessary to allow such apparatus to stand a long time before the absorbed water had freed itself from the glass. The same criticism applies to Von Zahn’s experiment with a sodium copper condenser mm vacuo, where the tube broke after the first observation. 27. The foregoing observations, the fact that gases under ordinary conditions are non-conductors, and the much greater simplicity of the theory, all point to the view that the so-called ‘‘ contact” effects are due to the action of condensed films on the surface of the metals. When the copper and zinc quadrants are wet with water, the difference of potential near them is practically that of the terminals of a cell formed of the same metals dipping in water. If instead of the water we use copper sulphate saturated solution on the copper quadrant and zine sulphate solution on the zinc, the difference of potential is almost exactly that of the Daniell cell, of which this arrangement is the analogue. In fact whether we break such simple galvanic circuits in their metallic parts, or in their liquid parts, we obtain the same value at the terminals in either case. _ 28. Considering: then the two metals of a copper-zine Volta con- deuser as the elements of a cell, and the moisture film on them as the electrolyte, we have a simple copper-water-zine cell, divided on its electrolyte, and showing, when the metals are clean, approximately the difference of potential appropriate to such a cell. The well-known experiment of Sir William Thomson, where a water-drop was placed between the previously disconnected metal quadrants, is thus easily explained. The water-drop connexion 1886. ] A Theory of Voltaic Action. 307 equalised (sensibly) the potentials of the films, by altering those of the metals which were previously at one potential.* 29. Hvidently then, as I have before suggested (‘ Phil. Mag,’ Feb., 1879), in experiments purporting to give the difference of potential between a metal and a liquid by the condenser method, such as those of Hankel, Gerland, Clifton, Ayrton and Perry, &c., we have really a two-fluid cell (one fluid being that under examination and the other that condensed on the metal plate), with a dielectric division of air between the two fluids. Any observed differences of potential can readily arise from differences between the nature and constitution of the film and those of the liquid under examination, even if the latter be water. The film can, for instance, more easily replace by absorp- tion from the air any oxygen in solution which may have entered into combination with nascent hydrogen liberated by the oxidation of the metal. These differences naturally cause different actions on the metal, entailing different states of its surface, which again react on the electrolytes differently. If in experiments of this kind the metal dipping in the liquid be different to that of which the plate is formed, we have of course then a two-metal two-fluid cell. 30. This aspect of the Volta condenser as a copper-fluid-zine cell divided in its electrolyte, suggested the possibility of joining the films only on the two metals, without bringing the metals them- selves in contact, and so producing a real galvanic current-producing cell from the apparently dry metals. This I succeeded in doing after a very great expenditure of time and patience; an expenditure partly owing to the unsuitability of the apparatus—the condenser, fig. 3, described § 20, having been designed for another purpose, was not capable easily of sufficiently fine adjustment. After the first few preliminary trials had given promise of a decided result, a micrometer screw was added, instead of the support at M, in order to be able to form an approximate idea of the distance between the plates during an experiment. The copper and zinc plates of the condenser were first carefully faced up to a plane surface by the use of a surface plate, and then lightly ground together with washed emery-powder, after which the zinc received a light rubbing with fine emery-paper. Wire connexions were fixed by screws to each plate, and the pair could thus be joined by means of a mercury cup arrangement either to a reflecting galva- nometer, giving a deflection of about seventeen divisions for a millionth * [When the quadrants of copper and iron were disconnected and then joined by a drop of potassium sulphide solution, the difference of potential near them was (as would be expected) increased instead of annulled, It became about double its former value-—November 1, 1886. ] 308 : Med. Browns: [Nov. 18, ampere current, or to a circuit consisting of a Leclanché cell and an ordinary astatic galvanoscope. A telephone was also generally included in the circuits. When joined up with the cell in circuit it was possible by very careful adjustment of the distance between the plates to find a point where although they were not in metallic contact still a current would pass. The needles of the galvanoscope (which flew to the stops when the plates were in actual contact) were deflected unsteadily to about the same extent as if the condenser were replaced by a resistance of 50 to 100 ohms, and a faint hissing sound was heard in the telephone.’ If now the terminals from the plates were transferred to the galvanometer, a current was observed varying in different experiments according to circumstances from a few up to 130 divisions, but which at once ceased when the plates were either placed in metallic contact or so far apart as to separate the films on them. rer: 31. Measurements of the thickness of the two films were made by the micrometer screw at M. Its indications are, however, only approximate, since the upper plate does not remain parallel to the lower while being raised; and also (the whole apparatus not being very rigid) it is quite possible that when the upper film rested on the lower one, there was sufficient pressure on the surface of the plates to prevent the upper one falling to the extent indicated by the micro- meter readings, although a weight of six pounds was placed on the end of the upper board at A to help to depress it. I give, however, a series of readings typical of those obtained in all the experiments. M denotes the reading on micrometer corresponding to the distance through which it rose in thousandths of aninch. D is the deflection on galvanometer. (The adjustment for great sensitiveness rendered its zero unstable. ) Hygrometrie state of air measured by Regnault’s form of hygro- meter was 0°77. Me O05! OIE PO DBO OSS a Og D0 By Om9e Tea OG D216) 290817 070! ! GO. 2029O° BBL OTage Mao LON Od eGR eae a Plates in contact. Films apart. M= 3:5 3 2-5 2 15 1 0:5 0 D=so 38 640 50 BO 50 15 Lo : ) Plates in contact. Hygrometric state of air=0°655— M= 0 1 i a 2 25 3 3°5 3 2°5 2 1°5 D=830 65 68 75 65 40 32 32 58 67 35 A —$$—— ae Plates in contact. Films apart. The plates were very carefully dusted before use with a camel- hair brush, and it was necessary also to avoid breathing on them, as 1886. | A Theory of Voltaic Action. 309 the slightest puff of breath over them caused the formation of a film, which, though quite invisible, easily formed enough current to send the index quite off the scale. 32. I now made some experiments to ascertain whether the film cell could be polarised by the current from a Leclanché element connected to the plates. The following examples show that this is so, and that the polarisa- tion effect is so great as at first even to overpower the ordinary electromotive force of the film cell. | Column I gives the mode of connexion of the poles of the cell to the plates; P the carbon pole. I1.—The deflection observed on the galvanoscope. Il1.—The zero point of scale of reflecting galvanometer. IV.—lts initial swing on having the terminals of film cell changed to it. V.—tThe point at which the index rested after its first swing. (1.) Hygrometric state of air=0:8— 12kO KORA 25 17 30 Falling. IPO Fie sss el 20 16 Rising. Readjusted plates. Pita Oute. <%.1,.. 12 30 45 | Falling. LOW 65 os aie 68 32 22 Rising beyond 32. Readjusted plates. Pio. Lildnl 16 40 60 47 Falling. PEO: Zs 0 00 of2 74, AA 31 40 Rising. (2.) Hygrometric state of air=0°826— 1 II. | III. | IV. | V: | PEAEO WIL .\ wia.5's 52 12 60 30 Falling. ELD) Zi Dire siahe\e 74 21 14 Rising till after some : minutes the deflec- tion passed the zero, showing the ordinary current from film cell. [32a. Several of the foregoing experiments go to show that a cessa- tion of chemical action at the surface of the plates implies a subse- =—4 "n°! ©. . au eR a i ee hy wl 310 Mr. J. Brown. [Nov. 18, quent disappearance of the difference of potential wear them, and a decrease of the former produces a subsequent decrease of the latter. In the case where the decrease of chemical action is due to drying, it is, perhaps, sufficiently in correspondence with the theory to sup- pose that when the film is partially removed, the effect it produces should also partially disappear, although we may not be in a position to specify the particular nature of the molecular process involved, or whether there is included with it anything of the kind described next following. In the case, however, of the hindrance of chemical action by the formation of an intervening oxide or other compound layer, there appears at first sight a difficulty, smce if may be said that after the separation and disposal of the two opposite charges on the two films resident on the metals in contact as above described, the mere forma- tion of intervening oxide on other layers would tend more to keep these charges apart than to allow them to combine. It must, however, be remembered that in this case the films them- selves are also in contact, and that a conducting connexion between them may reasonably be supposed to provide a continuous leak, by which the difference of potential suffers a constant reduction below — the normal, and. would, therefore, disappear altogether, if the leak were not greatly overpowered by continuous electrolytic combination at the surface of the metal. | The lateral resistance of the film must of course be very great, in order that so much difference of potential may be obseryable ; but it is obvious that unless the film were of infinite conductivity some difference would still exist. Where the metals are not in immediate contact the films on (or moisture in the pores of) the supports may readily provide the neces- sary electrolytic connexion, considering the very small quantities of electricity involved. I have observed that when the vulcanite piece, M, fig. 1, carrying the quadrants, became damp from remaining some days inclosed with the water in the vessel below it, the potential difference was considerably decreased. The existence of ‘local action” or local currents in the film would -geem also not improbable, and would account for some of the pheno- ‘mena connected with tarnishing, otherwise difficult to explain.— November 1, 1886. | ; 33. I may here refer to an experiment made prior to these last but related to them. It was based on the supposition that the molecules of water in the condensed film on a metal must (in order to oxidise it) have their oxygen atoms turned and attracted towards it, but if we could reverse this arrangement by attracting the hydrogen atoms, we might be able to retard the oxidising action. Possibly the fact ‘that the potential for a charged conductor is constant throughout 1886.] A Theory of Voltaic Action. 311 negatives this view. It was thought, however, the results might throw light on questions as to the molecular nature of any electro- chemical polarisation of the condensed films as a cause of the static voltaic effect, and for that reason they are here shortly stated. The condenser, fig. 3, was provided with a pair of zinc plates faced up together. The difference of potential of their films after metallic contact of the plates was tested qualitatively by a quadrant electro- meter in the usual way. A very small value was found, due doubtless to some slight difference in the state of their surfaces. The plates were then separated toa small distance, and joined to the opposite poles of a battery of 100 Daniell cells. After 175 days the battery was removed, and the difference of potential of the films on the plates again tested. It was supposed that if any greater oxidation of the positively electrified plate, as compared with the other, was caused by polarisation of the films, there would be a greater difference of potential than before; the film on the tarnished plate being negative. If anything, the reverse was the case, but the effect was very slight, and may have been due to some kind of storage cell action in the supports of the plates. A second trial with the Daniell battery joined the reverse way gave a like negative result. Probably the effect suggested does not take place, or it is masked by local actions in the film. | 34, An old experiment of Gassiot (‘ Phil. Mag.,’ vol. 25, 1844, p. 283), where electrical disturbance is produced by altering the capacity of a Volta condenser without contact between its copper and zine plates, which are merely connected to the gold disks of an electroscope, is assumed by some authors (Von Zahn, ‘ Untersuchungen. iiber Contactelectricitit,’ p. 55; Wiedemann, ‘Lehre von der Elektri- citadt,’ vol. 2, p. 988). to be difficult or incapable of explanation by the contact theory, though I think wrongly so, as there is contact of dissimilar metals, viz., copper-gold and zinc-gold on the connexions to the gold disks of the electroscope used. (Von Zahn’s inability to repeat the experiment so as to get Gassiot’s result seems to me unaccountable. ) : 30. In order to exclude any uncompensated contact of dissimilar metals, as in Gassiot’s experiment, I modified it by joining the copper plate of the condenser, fig. 3, to the copper quadrant in the electro- meter, fig. 1, and the zinc plate to the zinc quadrant. The latter connexion was made by a copper wire, but the dissimilar contacts thereby introduced compensate one another. ; On altering the capacity of the condenser a very decided alteration of the potentials near the quadrants was observed. The following table gives the results :—Column I gives the sign of the electrification of the needle. II, the position of the index with condenser plates apart. III, the point to which the index swings on closing them to VOL, XL. ¥ 312 oc) Ma. J? Brown, [ Nov. 18, within about 0°01 inch. IV, the point where index came to rest with the plates so closed. V, the swing on separating the plates. VI, the final deflection with plates apart. The prefix L signifies a left-hand deflection towards the copper quadrant; RK a right-hand one towards the zinc quadrant. SD L 44 L 29 L385} L55 | L435 - R55 R395, R485| R66 | R54 _- R 54 R38 R48 R63°5 | R535 ais L 44 L 32 L 39 L51:5| L435 It is evident there were electrical charges present, although there was no actual metallic contact at which any ‘‘ Scheidungskraft ” could exist to produce them. (See Appendix.) 36. In conclusion, the following diagrams represent the distribution of potential according to the theory here adopted. Fig. 5 gives the state of things in a closed zinc-water-copper cell of uniform resistance throughout its circuit; N and P understood as joined in closed circuit. Fig. 6 shows the same cell with the metals apart; the two metals being covered with moisture films, which are practically a portion of the electrolyte and (in so far) at the same potential. This shows also graphically the explanation of Sir William Thomson’s “ water- drop ” experiment, referred to before (§ 28). Fig. 7 is a cell divided in the copper part of the circuit, where instead of the potential of a film on the zine, as in fig. 6, we have the lower potential of that on the copper piece connected to the zinc. The terminals of like metal in this way permit the electromotive force of the cell itself to be measured in the usual electrometric way. Fig. 8 represents either a zinc-water-copper cell divided in its electrolyte, or the ordinary static experiment where the difference of potential of the films on two metals in contact is measured. It is to be borne in mind that these diagrams are only of a qualita- tive nature, as the difference of potential between the dry metals and water, &c., in contact with them has not yet been experimentally determined, Appendix, The experiment described, § 35, leads to the following theoretical considerations which have been in part suggested and put into form by Mr. J. Larmor, of St. John’s College, Cambridge. 1886. ] A. Theory of Voltaic Action. 313% 37. The zinc sector of the electrometer and the zinc plate of the condenser in connexion with it form an insulated conductor of zinc; the copper sector and the copper plate of the condenser form an insulated conductor of copper. Consider first the hypothesis which asserts that after recent metallic connexion, the potential of the zinc exceeds that of the copper by a definite amount. The plates being primarily at a distance, make them approach each other gradually. As they do so the experiment shows that the difference of potential between them gradually diminishes. Their behaviour is just that of an ordinary charged condenser; as the plates come closer together their capacity is increased, being always inversely proportional to their distance, and therefore for a given charge the difference of potentials is diminished, being always directly proportional to their distance. By bringing the plates very close together their difference of potential may be reduced indefinitely. Having brought them within avery minute distance of each other, establish metallic con- nexion between them. According to the hypothesis this restores. them to their original difference of potential. This is done by the separation of a quantity of electricity equal to the difference of potential multiplied by the capacity of the condenser; the two plates. acquire charges of this amount but of opposite signs. This operation involves a gain of energy to the system of amount equal to half the capacity of the condenser multiplied by the square of the difference of potentials. The plates being very close together these quantities are of considerable magnitude. Now the operation of making metallic contact was merely directive and involved no supply of energy from without. This supply must therefore come from an absorption of the heat of the system, or from chemical combination either partial or complete. The first alternative is inadmissible, as it would lead to a perpetual motion; we are, therefore, driven to that of chemical combination, which may either be an action between the zine and copper at the point where the metallic connexion is made, or an action between one or both of the metals and the surrounding gaseous medium. In either case its amount, though very minute, is not infinitesimal. As there is no evidence of any action between clean zinc and clean copper at ordinary temperatures which involves any liberation of energy worth considering, it seems nearly certain that the actual liberation of energy is due to the other cause, which in the atmosphere is oxidation whether nascent or complete. The plates with their acquired charges may now be separated by mechanical energy, and their charges imparted to an electric receiver by contact. The plates being now as at first the same cycle may be repeated indefinitely, and a permanent supply of electricity may be thus theoretically obtained at the expense of continued oxidation of the plates in air, we 314 A Theory of Voltaic Action. [Nov. 18, These considerations apply very much in fact to Sir W. Thomson’s gravity battery with copper filings and zinc funnel. . 38. But now suppose that any atmosphere capable of acting che- mically on the plates has been removed. On bringing them close together and making metallic connexion between them, they will not be able to return to their original difference of potential, for the energy required to effect the electrical charge is no longer forth- coming. The facts thus far encourage us therefore to hold the view that the difference of potentials is not an intrinsic property of zinc and copper in themselves, but is the result and manifestation of the fact that their contact in the atmosphere has started a chemical action which has proceeded till choked off by its own results. According to the ideas of the theory of chemical equilibrium of Clausius, Gibbs, and Helmholtz, it has proceeded until the accumula- — tion of its products has secured that further progress shall not any longer lead to a dissipation of energy. 39. Tf this argument which refers the difference of potential to an initial chemical action on the surface of the plates where they are in contact with the atmosphere or to a condensed liquid surface film derived from it, be allowed, the next step would be the assignment of some mode of action which would account for the result. And here the idea of a double electrical layer, which has been elaborated by Helmholtz from the phenomena of electrolysis, and so successfully applied by him in explanation of the polarisation of voltaic cells, comes up hopefully. The oxygen of the moisture in the atmosphere will under proper circumstances combine chemically with the zinc, giving rise to electrical effects, as in Sir W. Thomson’s gravity battery already mentioned. When the circumstances are such that actual combina- tion is not possible, the two substances will feel each other’s presence, and take up along their surface of contact a conformation of mole- cular equilibrium; we have a right to assume that this configuration will present a sheet of positively charged atoms, facing an equal sheet of negatively charged atoms, and thus forming a double layer. A precise explanation of how this comes about could hardly be required of us, for so long as we continue to apply to such questions our ordinary notions of electrical attractions at all, there is no way open for explaining the dynamical fact of a difference of potential between two substances in contact, except the assumption of such a layer along the surface of contact. How it is formed may be at any rate illustrated from the phenomena of voltaic polarisation. 40. We may then provisionally contemplate a zinc plate as surrounded by such a double layer, negative inside and positive out- | side ; and a copper plate as surrounded by a similar layer of smaller moment, the moment being measured in the same way-as for magnetic (JBrown Proc.Roy. Soc: Vol. 41. PU.4. Pig Ser West Newman & Co.lith J. Brown. Prow Roy.Soc. Vol. 41.PU.5. IN Fulm on Gave Film orn Copper N Cw Z 2 toe Le Iga se Cw ke ake). © FuGm on Copper - FU or. Copper Wee Me a | : Give Gia Tw Gi. Ful or Water om Lue Film or Water on Copper West Newman &Co hth 1886. | The Coefficient of Viscosity of Atr. 315 shells, by surface density multiplied by distance between the com- ponent layers. When the two plates have attained electrical equil- brium with surrounding objects, the potentials just outside the layers will be equal (e.g., by electrolytic connexion as in Sir W. Thomson’s experiment of a zinc and a copper plate connected by a drop of water), but the potentials of the metals inside will be different, each being less by the moment of its layer. The zinc will therefore be at a lower potential than the copper. If a metallic connexion is now made between the metals, positive electricity will flow from the copper to the zinc until the potentials of the metals are equalised, and the difference of potentials of the air outside the plates will now be exactly opposite to that which subsisted between the metals before metallic contact. There is this difference between the view just mentioned and that of pure contact difference which was examined, § 37, that here the metallic connexion involves a running down of electric energy, while there it involved an addition of energy from without. 41. The explanation by superficial double layers once accepted, there is no longer any reason for retaining contact of the two metals as one of the conditions necessary for the setting up of this action between a metal and its surrounding atmosphere. We may hold that when a piece of clean zine, or a piece of clean copper, kept insulated, is introduced into an atmosphere capable under favourable circumstances of acting chemically upon it, a change of a chemical or semi-chemical character is thereby initiated over its surface, which involves a transformation of energy, though in minute quantity, and which proceeds until a state of equilibrium is estab- lished, as indicated by the setting up of a certain definite difference of electrical potential between the metal and the gas near it, but out- side the sphere of the action. VI. “ The Coefficient of Viscosity of Air. Appendix.” By H@RBERT 'TomLiInson, B.A. Communicated by Professor G. G. STOKES, P.R.S. Received November 15, 1886. (Abstract. ) In the previous experiments by the author on this subject the coefficient of viscosity cf air was determined from observations of the logarithmic decrement of amplitude of a torsionally vibrating wire, the lower extremity of which was soldered to the centre of a hori- zontal bar. From the bar were suspended vertically and at equal distances from the wire a pair of cylinders, or a pair of spheres. The distances of the cylinders or spheres from the wire were such that the 316 The Coefficient of Viscosity of Arr. [Nov. 18, maw part of the loss of energy resulting from the friction of the air may be characterised as being due to the pushing of the air. A small part, however, of the whole logarithmic decrement was due to the rotation of the spheres or cylinders about their axes, and Professor Stokes has kindly added to the paper a note in which are deduced formule which serve to correct for this effect of rotation. Acting on a suggestion of Professor Stokes, the author proceeded to determine the coefficient of viscosity of air by suspending a hollow paper cylinder about 2 feet in length and 4 foot in diameter, so that its axis should coincide as to its direction with the axis of rotation. The cylinder was supported by a ight hollow horizontal bar, about 7 inches in length, to the centre of which the vertically suspended wire was soldered. The wire was set in torsional vibration, and the logarithmic decrement determined with the same precautions as before. The mode of eliminating the effect of the internal friction of the metal wire, and also the effect of the air on the ends of the cylinder, is fully described in the paper. . The following were the results :— Vibration-period Coefficient of viscosity Temperature in degrees in seconds. of air, y. Centigrade. 3°6038 0:00017708 12°225 8°8656 0:00017783 13°075 In these experiments the loss of energy arising from the friction of the air may be characterised as being due to the dragging of the air, and it is very remarkable that there should be such close agreement in the values of «4 as determined by this and the previous ‘methods. The mean value of the coefficient of viscosity of air obtained by this method is 0°00017746 at a temperature of 12°650° C., and the mean value deduced from the previous experiments when proper correction has been made for the rotation of the spheres and cylinders about their axes is 0°00017711 at a temperature of 11°79° C. The above values of w are given in C.G.S. units. The author expresses his great obligation to Professor Stokes for his valuable suggestions and advice during the progress of the in- vestigation. 1886.] A finities of Thylacoleo carnifex, Ow. 317 November 25, 1886. Professor STOKES, D.C.L., President, in the Chair. In pursuance of the Statutes, notice was given from the Chair of the ensuing Anniversary Meeting, and the list of Officers and Council nominated for election, was read as follows :— President.—Professor George Gabriel Stokes, M.A., D.C.L., LL.D. Treasurer.—John Evans, D.C.L., LL.D. Professor Michael Foster, M.A., M.D. Secretaries.— { The Lord Rayleigh, M.A., D.C.L. Foreign Secretary.—Professor Alexander William Williamson, LL.D. Other Members of the Council.—Professor Robert B. Clifton, M.A.; Professor George Howard Darwin, M.A., LL.D.; W. T. Thiselton Dyer, M.A.; Professor David Ferrier, M.A., M.D.; Edward Frank- land, D.C.l.; Arthur Gamgee, M.D.; Archibald Geikie, LL.D. ; Professor Joseph Henry Gilbert, M.A.; John Hopkinson, M.A., D.Sc.; J. Norman Lockyer, F.R.A.S.; Sir Lyon Playfair, K.C.B., LL.D. ; Professor Bartholomew Price, M.A.; Professor Pritchard, M.A.; Admiral Sir George Henry Richards, K.C.B.; Professor Arthur Schuster, Ph.D.; Philip Lutley Sclater, M.A. The Presents received were laid on the table and thanks ordered for them. } The following Papers were read :— I. « Additional Evidence of the Affinities of the Extinct Marsupial Quadruped, Thylacoleo carnifex, Ow.” By SIR RICHARD OWEN, K.C.B., F.R.S. Received October 5, 1886. (Abstract. ) The subject of this paper is an entire lower jaw of the large extinct marsupial which the author from previous fragmentary fossils con- cluded to be part of a carnivorous beast of the size of a lion, the probable prey of which had been the larger herbivorous marsupials, also now extinct. Every additional character in the subject of the present paper confirms the fitness of the genus named Thylucoleo. 318 On Entyloma ranunculi (Bonorden). [Nov. 25, Il. “On the Structure and Life-History of Hntyloma Ranuneuli (Bonorden).” By H. Marsaann Warp, M.A., F.L.S., Fellow of Christ’s College, Cambridge, and Professor of Botany in the Forestry School, Royal Indian Engineering College, Cooper s Hill. Received October 12. (Abstract. ) The author found plants of Ranunculus Ficaria, the leaves of which were all spotted with white patches; the white patches spread from leaf to leaf, and the disease assumed the nature of an epidemic. The rise, progress, and climax of the disease were observed: both ‘on isolated plants and in the open country, and the nature of the lesions in the leaves was made out. Evidence was found to support the view that some plants succumb more rapidly; this evidence was tested, and the circumstances to which the differences are due ex- plained. The white disease-spots contain the extremely delicate mycelium of Hntyloma Ranunculi, and the resting-spores of this fungus (one of the Ustilaginez) were observed on it. The mycelium is intercellular, and makes iis way in the middle lamella between contiguons cells. The white powder on the outside of the disease-spot consisted of conidia, very like those of some Ascomycetes. The author examined the anatomical connexion between the conidia and the resting-spores, and showed that the conidia really belong to the same mycelium —in other words, the conidia are a second kind of spore of the Entyloma. Even more important is the germination of the conidia. This has not been before observed in any Hntyloma. The germination was traced step by step, not only on glass slips, but also on the living plant. These infections yielded the result that the germinal hyphe entered the stomata, and produced a mycelium exactly like that in the disease- spots first investigated; not only so, but the resting-spores of the Entyloma were produced on this myceliwm, thus placing beyond doubt the connexion of the two spores. It was observed that it required a certain time for the disease to spread: this interval of time is the same as that occupied in infecting plants with the conidia. Moreover, all the symptoms of the disease produced by infection with the oqiadne were as before. Peco; On a Rotating Mass of Fluid. 319 III. “On Jacobi’s Figure of Equilibrium for a Rotating Mass of Fluid.” By G. H. Darwin, M.A., LL.D., F.R.S., Fellow of Trinity College and Plumian Professor in the University of Cambridge. Received October 12, 1886. I am not aware that any numerical values have ever been de- termined for the axes of the ellipsoids, which are figures of equi- librium of a rotating mass of fluid.* In the following paper the problem is treated from the point of view necessary for reducing the formule to a condition for computa- tion, and a table of numerical results is added. Let a, 6, ¢ be the semi-axes of a homogeneous ellipsoid of unit density ; let the origin be at the centre and the axes of 2, y, z be in the directions a, b, c. Then if we put— ; =a +u, 2—=F2? + u, C=c?+u, and * du ¥=| ay G4 . . . ° . ° . (1) it is known that the potential of the ellipsoid at an internal point @, y, 218 given by— sees yi adv ydv z2dyv¥ : srabe [v4 4 ES ==). (2) Now let us introduce a new notation, and let * The following list of papers bearing on this subject is principally taken from a report to the British Association, 1882, by W. M. Hicks :— dacobi, ‘ Acad. des Sciences,’ 1834; Liouville, ‘Journ. Ecole Polytech.,’ vol. xiv, p. 289; Ivory, ‘Phil. Trans.,’ 1838, Pt. I, p. 57; Pontécoulant, ‘Syst. du Monde,’ vol. ii. The preceding are proofs of the theorem, and in more detail we have :— C. O. Meyer, ‘Crelle,’ vol. xxiv, p. 44; Liouville, ‘ Liouville’s Journ.,’ vol. xvi, p- 241; a remarkable paper by Dirichlet and Dedekind, ‘ Borchardt’s Journ..,’ vol. lviii, pp. 181 and 217; Riemann, ‘ Abh. K. Ges. Wiss. Gottingen,’ vol. ix, 1860, p- 3; Brioschi, ‘ Borchardt’s Journ.,’ vol. lix, p. 63; Padova, ‘Ann. della Se. Norm. Pisa,’ 1868-9 (being Dirichlet and Riemann’s work with additions) ;° Greenhill, ‘ Proc. Camb. Phil. Soc.,’ vol. iii, p. 233 and vol. iv, p. 4; Lipschitz, ‘Borch. Journ.,’ vol. Ixxviii, p. 245; Hagen, ‘Schlémilch Zeitsch. Math.,’ vol. xxiv, p. 104; Betti, ‘Ann. di Matem.’ vol. x, p. 173 (1881) ; Thomson and Tait’s ‘ Nat. Phil.’ (1883), Part II, §778; a very important paper by, Poincaré, ‘ Acta Mathem.,’ 7, 3 and 4 (1885). _ + Thomson and Tait’s ‘Nat. Phil.’ (1883) §494, 7, The form in which the formula is ‘here given is slightly different from that in (8), (11), (15) of §§ 494, &, 7. 320 Prof. G. H. Darwin. On Jacobi’s Figure of [Nov. 25, c=acosy, sina = == and b=a cos f, —c (3) so that sin B=sin asin y, and b=a/(1—sin2a sin?y.) a—C? sin’y ) ] t — 2— —— 72 5 gana See 8 | whence B=u+e= a —— (1—sin?a sin’@), | asin? C?=u+c?=—- c0s?0, eae sin*0 ; and ieee” BEN, os 0 d0, fe sin’d and | du= 2utsin’y | 2 a sin?y a dry. | 0 0 sin°0 gst in'y ot Lastly, let A=./(1—sin?a ay and in accordance with the usual notation of elliptic integrals let pa( E | ONE SS. =| Ady. 92 aaa iE A : (9) Then we have the following transformations :— a v -| ae : pABC asing dv ae 2 ¥ sin?y — = — dl —- F—E ada =| ABBO ~ absindy \ ne 1 asin2a td ) : aa ape 3/3 oe a Ysin? in 7 bdb =| aFO — asindy Jy Ae 7 ay du 2 “tan2y — = =) Wer 230:n8.. dry COC. Hy BO orsinvy \ 1 A It remains to reduce the last two of (6) to elliptic integrals. If k and kh’ be the modulus and its complement, the following are known transformations in the theory of elliptic functions, viz. :— [da at k?sin y cos y —~— 3 —TJFTo ie FO ee ae . . . e . 7 la Mee k'?A : (7) Y tan2q Atany: 1 —— Pe iy ; \ A a h'* A Oe Th saath, ae (8) Y sin? 1 (7 2+A2 1 sinycosy 1 sinty et) Mins seiitiey Cail yh yeh yore | Ula a Tet OS peli pe oe 1886. ] Equilibrium for a Rotating Mass of Fluid. 321 In the present case k=sin a, k’=cos «a, A=cos 8. Thus (8) and (9) enable us to complete the required transformation to elliptic in. tegrals of (6). Substituting then from (6) (8) (9) in the expression ae dv y? dv z2 els Varin 4} corr aa Ie aR == @ — 477938 where m = 4+7rabe =£7a*cos B cos y, we have asiny asin®y sin y COs y F cos*acosB sin?a sin?a ee =) aa s( ag) tag (Eton y 008 8) |. do) Now suppose the ellipsoid to be rotating about the axis of z with an angular velocity w, and let us choose the axes a, acos 6, a cos y, and the angular velocity w, so that the surface may be a surface of Pete, For this purpose V +1w?(«?+y?)=constant, must be identical with at ea coy oe Now in (10) we have V in the form Vie ye Ne P.O ee ELL) whence a®(L +4 a) =a2(M+2 w) cos?B=a2N cos*y. Hence L—M+N cos’y tan?@=0, 7 tu2=N cos*y—L, és een: Cla) or w*sin?B= M cos*B—L. There are two kinds of solutions of these equations (12). First, since dv L=~7b SSS 3 3 or. ™a”COS B COS y Bg 0O8 cos Bc COS sin?ry ty sin?y A dv 1 fc mae —7a°cos B cos y . ———s— cos 8 cos sin®,, ASSN seal a an if sin*y Qo it ig obvious that L—M vanishes when «=0. 322 Prof. G. H. Darwin. On Jacobi’s Figure of [Nov. 28, And since when « vanishes, 6 also vanishes, the equation L—M-+N cos?*y tan?B=0 is satisfied by ae a s=0. That is to say there is a solution of the problem which makes C=) s Thus there is solution which gives us an ellipsoid of revolution. When sin «=0, we have also B=0, A=1, and Qrecosy(” . , 7C f= er, sin*y dy= inky 7 (sin Yy COs Y—V) BeOS dane dy=" i 2 tan y). Pe Mami aad a Y Therefore ay PINT Eten 50"=N cos*y—L, = By —,- [2y—2 tan y— (1 + tan®y) (sin y cos y—) J, = ca ty@+tonta)—3tamny, 2... and the eccentricity of the ellipsoid of revolution is sin ¥. To find the other solution when @ is not zero, we have by com- parison between (10) and (11), sin2s sin®y E_F 9 " 2rcosBcosy — sin’asin’y sin®a sin y cos 7 27 cos B cos y cos*a cos B +F—Esecta, 4 . (15)) sin*a sin?y | ba Roa he: : ; Dados tan?a(H—tan y cos B) ; Hence the first of (12) gives —(2F—E) +E sec?a sin?s siny cosy _ + tana tan®® cos*y(H—tan ¥ cos 8) ipacamiesasias COs*a cos i Compare with Thomson and Tait’s ‘Nat. Phil.,’ aa (8) or ay other y work which gives a solution of the problem, 1886.] Equilibrium for a Rotating Mass of F'luad. 323 or Esec?a{ 1+ (sin 2 tan B cos 7)?]—(2F—E) —sec’z sin a tan Bcosy(1+sin?8)=0. . . . (16) In order to adapt this for computation, we may introduce the auxiliary angles defined by tan €=sinatanBcosy,tanéd=snf,. .. . feu) and the equation becomes | K cee sec?¢— (2F—E)—sec*z sec’étang=0. . . (18) The second of (12) gives w* sin?z sin?y = tan?z cos*y(H—tan y cos 8) —(E—F), 47 cosBcosy a dee Keos*y __cos Soe Ease 4 cos B cos 1 sin? sin3y ' sin3ycos?e cos’a sin’ whence 2 “=cot B cosec B cot y(F —E) + cot®y cos 8 sec?«H —cos?B cot*y sec?a. = (19) Some of the subsequent computations were, however, actually made from a formula deduced from the third of (12), which leads to 2 : *=cot B cot y cosec?B(1 + cos?8)(F — E) —cot38 cot y tan?« cosec BE 4a + cot?B cot*y sec’a. ... (20) By subtracting (20) from (19) we can deduce (16); hence it follows that (19) and (20) lead to identical results. Most of the subsequent results were computed from both (19) and (20), thus verifying the solution of (18). The formule (18) and (19) are suitable for finding the solution, except when 2 is small or nearly 90°, when the elliptic integrals become awkward to use. I have, therefore, found approximate formule for these cases, but as the algebraic process necessary to establish them is somewhat tedious, the details are given in a note.* * Approximate Solutians of the Problein. From (7) we have { sim yg _ pie a Ay: é A? ' = A? 1 sin y cos y =p Bp OEE) pO 324 Prof. G. H. Darwin. On Jacoli’s Figure of [Noy. 25, Approximate Solutions of the Problem—continued, Now, since (16) may be written k? sin y cos kA ON ae sin?y cos?y 7 TA E + 3 “tan |, if Hae — (2F—E) — it follows from (a) and (8) that it may be written : Y : Us sid o% tan? “| aa dy=sin?y cosy ade ohn dep icp eee ’ o A Again, we may write (19) thus :— w Acos SYR E) + Acos*y,, A*cos*y An ksin?y kindy >sin?y _A maces y{ Pca ae A a " tanty a sin?y A sinty A (apes _ Acosy sin*y J x ’ sin*y i Amo 0 2 oar]... Tt is easier to develop the equations when written in the forms (6) and (c) than when we work directly from the elliptic integrals, Write for brevity k=sina, g=cosa, p=cosy, g=siny, Q=tany, A=log.cotG@a—3y). First, when k is small— The following definite integrals are required :— uf n—1 n | eal tn fin OE n—2 ea ie {o dy. 2s = 9) see n n—1 eur eee Se a 1 3 3.5 2 Eee 2 2 4,4 From (d) and from =: =1+5k¢ +5 hg +o. g! at gies 3.1 S( 1 5 5.8 5.3.1 \s gas aed? hae te" \e le? ae tom en + (f) =1—f'q’, and q' 1 3 3.1 31 1 35 31 Re 98 pe wales il ide (eradcemehidieaa |= ya, Mae. Oo |S Wg Pate eae 62° 4)? \Gan ape 3853. +> (3832_31 V1 , 2.6.4.2 2 2.6.4.2 4.22 ik 1 3 3 15 es _3 eo ie = 2 rE, its 2 5 ote 1 Again, mot + 5 hig? + »» 4 and by (e)— 1886.] Equilibrium for a Rotating Mass of Fluid. 325 Approximate Solutions of the Problem—continued, [Siey—[ Bayt 7st [2 +20p-27] .., pre | Lay PPP Pay : ke Ez = Pa + 5 Pa a So | 7) =p rey 8( boat +2p0— Sate) + ah ae SM ma . ° 2 The equation (4) is p’q? [ayaa ae zd whence, equating (g) and (A), 5 8 11 15 Se 3 is Pas 2 gt iapt epg =7( +3? “gt) +h | - 4PY +76 PY +55 Pa— -(B + eo ia’) | + ...=0. 5 If & be zero, we have a2 ‘p+ pq— —r(3 +p"q :)=0. : : in 2y —-5, sin 4 1 _ Sin 2y—3% sin 4y | 4 This easily reduces to Wr cos OR Rea ee ek) of which the solution is y=54° 21’ 27”, as stated in the text. Now d|5 3 I : ae +|3 ap + -p9- -7(3 +r) = —5 [1-2 cos 2y + cos dy + sin 4y], and with the above value of y is equal to —0°1355014, Also, with this value of y the coefficient of k? is 00160432 ; so that 0:0160432 sin (y—54° 21’ 27”) =0°135501422, or, sin?x = 1092658 sin (y—54° 21/ 27”), which is the equation (21) of the text. Y : 1 1 3 Again | fe=—Lept brs} (—Loe—2ar+3) 0 p? Y y= ip 2) 1 ie 3 yee (l— 5 ae iL 2 =e -O-Dyt5 eM \ p+ capl—g)— py 9’) =gp—7t y+ 8 igi + 9p ay + og? , 2 2 De Deo Therefore [far-re| Sy=—Son (3 r+} aay y—P ap +(% ~34)y |. : ‘Now A=1—}3h'7?=.., 326 Prof. G. H. Darwin. On Jacobi’s Figure of [Nov. 25, Approximate Solutions of the Problem—continued. Therefore Bee ol OS .3 age | \am “3 i | = “pa +(5 q° W so id 15 15 45% | GT PsP Nee “o-Gdop elie teh tev) Hence from (c) and (7) ei 3 w 3 2 3 2 15 ie 2 20)2 Fea 5qslO+ Wy-8A]+ 5 Ge| gFO- GB O+( Gee reer), which is the equation (22) of the text. Secondly, let k be neariy unity and g small— Then we require the following definite imtegrals :— grt} 1 Fe gr} bs aE : dy= (i= eee teeny Vee est / wif) gto nae eae | Poa oa | fy, a) = . ¢, ‘a { 8 2 Edy SMe Oe [tiv | 0 Now A?=1—k'q?=p*(1+9°¢"p-). Anse ak Se ie sk Sy (ee ee A* al ao gt” ) By (x) and ()— A2 Now ' i therefore AA g? ee ie = {Bop 3 meer 2 raceme ea +9" eit ae pelt +9 (Fae aay But b ST Q?,. a Z therefore A, qt 3 4 1 15° 28 i ees A pee pee pee 74 —() eae 2 pase ! | ay = Fi[2+5@ +32 sl - eer ae tat) : oe fisers (lS Bora)) os 2 6 Equilibrium for a Rotating Mass of Fluid. 327 1886.] Approximate Solutions of the Problem—continued. s sage 1 Again col Pears) (gr age oe ) gain, anal! aye ) Sha 2s ee 6 4 Pe Bere NPB 2 1 3. 3 i 1 5 Bi Bo, BB Rat 70? + 9 — ie Se =} Sey QC) SS ae (eee pee et [a i (520 “78 ZA )+( a) 59°| (722 4,319 z.at*g 34) 1 3 3 3902 4 Lg a= +(500 +59 54) |. _t 2 1 2 3 1 2 1 4 A 3 2 =59(1+Q) +509 (5 +5048 —5A(1+=92).-- Q? Qay=2 Eo +9? (535 oo) ~5a(5o +570) 2 (n) The equation (6) for determining the axes is £[e-e| So Hence equating (m) and (zm) and dividing by =9 we have 4areg (4a sa'e sa") —2| 145 ares ara) |. . =0, which is the equation (23) in the text. The equation (c) for w may be written f= Gl 1+) [fay | oa| pe fe ib eG Z)+ -(1-5)a-s)-5 0 | jae +505 | eres sa] |. a+ey(far—a{ (j-1)a+er+ 50 -[Faa+ay—pa+ay] } [Eerea{ga+a- -asbe[ptee—at-o4 | | asan|fey -|So =q ens (2+0°)-3a+0. aR +50") p29 | -70'| }. Z VOL. XLI. ES ee, 328 Prof. G. H. Darwin. On Jacobi’s Figure of [Novy. 25, If « be infinitely small, so that the Jacobian ellipsoid of three unequal axes becomes in the limit an ellipsoid of revolution, we have ¢ given by 1) ae __ sin 21 — x's sin Airy 1—icos 4y The solution of this is yor OC BB If we write tany=/f, as in Thomson and Tait’s ‘Natural Phi- losophy,’ §778’, this equation becomes tanlf 14+43f? jf It eee which is the equation (9), §778’, of that work. The ellipsoid of revolution of which the eccentzicity is sin 54° 21' 27” belongs to the revolutional series of figures of equilibrium, and is the starting point of the Jacobian series of figures. As shown by Sir William Thomson, it is the flattest revolutional figure which is dynamically stable. The Jacobian figures of equilibrium are initially stable, and as stated by M. Poincaré,* there is for this value of y a crossing point of the two series, and an exchange of stabilities. If « be small, it appears that sina is given by sin2a = 10°92685% gin (y—54° 21'27"), . . . QL and w by w2 = 3 ae +tan*y)y—3 tan yx] 7 +35 q—*¢ tan y+9( 3 —(3—sin’y) tan’y)] . (22) Approximate Solutions of the Problem—continued. Now A=p (2 + a ; .) Therefore a[ +a (far | Pay] = raf FG +0")-F0+0 ee EG +2Q%+ ei) 1 te te i. Hence os oy at +Q)-F A+) 45 abG spol Fe-Te'| }, which is the equation (24) in the text. * “Sur l’Equilibre d’une Masse de Fluide, &c.,”’ ‘Acta Mathematica,’ 7, 1886. 1886.) Equilibrium for a Rotating Mass of’ Fluid. (329 These formule are, it must be admitted, of but little use; since it : would be necessary to take in higher powers of sina to obtain nepitles for a variation of y of more than 1°. ; yee Tf « be near 90°, so that cos a is small, the approximate equation between «2 andy is © 1+tan?y+cos’a(15 + 27 tan’y +3 tanty +2 tan®y) log cot(g7—Fy) . [1 +2 2 tan?y + cos’a(415+ 12 tan®y+tan4y) | =0. . . . (28) sin ¥y And w is given by las losedi(e 4 1) . (2+ tan?y) —2 sec®y w? ., sin2y Acr bo|H . tandy_ +4 cos*« E log-cot(47 —Sy) . (442 tan*y + tan4ty) —2— 2 tan®y x Y —Hianty]). 2 (24) Syercrail return later toa modification of (24) which will he applicable to very long ellipsoids of equilibrium. Besides the angular velocity and the axes of the ellipsoid, the other important functions are the moment of momentum, the kinetic energy of rotation, and the intrinsic energy of the mass. In order to express these numerically we must adopt a unit of length, and it will be con- venient to take a, where a? = abe = acos B cos x. Thus a =.a(sec B sec y)?. Let o be the density of the fluid which has hitherto been treated as unity, and let (470)1a°n, (g7)/are be the moment of momentum and kinetic energy, then (470) 2a°u—= 3m (a? + b*)w= st 7ea°(sec B sec y)?(1 + cos’B) (Aro) =). TO Thus p =1,/3(sec Axce DAL +eos?s)( =) ee ee Co The function (25) is the quantity which will be tabulated. 2\3 Again (470)*a'e=4t 4a) al p.w=t/3(4r0)?a5. pw 2 ; dae = bins w* so that | = / ot ( ree (26) 330 Prof. G. H. Darwin. On Jacobi’s Figure of [Nov. 25, The function (26) is the quantity which will be tabulated. Thus in the tables the unit of moment of momentum is taken as (47c)%a°, or m2a3, and the unit of energy as (47<0)?a® or m?/a. It remains to evaluate the intrinsic energy, or the energy required to expand the ellipsoid against its own gravitation, into a condition of infinite dispersion. If dé be an element of volume, then this energy is == integrated throughout the ellipsoid. This will be denoted by (470)?a°(t—1), or m?a~! (¢—1), so that 7% will be positive. Now V=L2?+ My?+ Nz*+/P, and if we denote by A, B, C, the prin- cipal moments of inertia of the ellipsoid, we have | || dt=1(B+C—A) =2ma?, Rn and similarly, | | ya dt=1mb, \ |e. di=2 me. Also [[Jeae=m. | 2 Hence ™ (i—1)=~)m[La?+ MU?4+NE+5P] a =-,1,ma*(sec 8 sec y)3[L+M cos*B+N cos*y+5Pa?]. But if we take the values of L, MW, N given in (15), and note that By P = 7a®cos B cos y . — asin y it easily follows that L+M cos?B+N cos*y+Pa?=0. 2 Hence —” (i—1)=—2ma?(sec B sec y)?. Pa-? a — 2 9 2 aul — = — 2ma?(sec Bsecy)* . = Bae Fae 3 m* (Cos p cos ha “ sin y Therefore jan pura (On Bees hn isi). rn sin For a sphere + becomes infinitely small, and F becomes equal to ¥, — so that F/siny=1. Thus i—l=—%. Therefore the exhaustion of 1886. ] Equilibrium for a Rotating Mass of Fluid. 331 energy of a sphere of radius a is 2m?/a; which is the known result. For an ellipsoid of revolution «=0, and B=0, and F=y4; so that The function (27) is the quantity tabulated below. It seemed pre- ferable to tabulate a positive quantity, and it is on this account that the intrinsic energy corresponding to the infinitely long ellipsoid is entered as unity. Having now obtained all the necessary formule, we may proceed to consider the solution of the problem. We have to solve sec*a sec’¢ H—(2F—E)—tan €sec®asec*é=0, . . (28) where tan€=sinatanfcosy, tanéd=sinB=sinasiny, Y d Y and P=| ; 1D =| cos 8 dy. 9 cos B 0 The axes of the ellipsoid are a 1 4 ee is (sec B sec 1), = cosy: - (29) . Lf e), eg, eg, are the eccentricities of the sections through ca, cb, ab respectively, we have é,= sin f, €)= sin y, €g= coSasinysecfB. . (30) Having obtained the solution, we have to compute 2 == cot 8 cosec f cot y(F— E) + cot? Bcos 8 sec?«K—cos?B cot*y sec?a* (31) Then we next compute w and e and 7 from the formule (25), (26), (27). The functions F and E are tabulated in Table IX of the second volume of Legendre’s,‘ Traité des Fonctions Elliptiques,’ in a table of double entry for a and y¥ for each degree. The solution of (28) by trial and error was laborious, as it was necessary to work with all the accuracy attainable with logarithms of seven figures. The method adopted was to choose an arbitrary value ‘of y, and * As stated above, some of the computations were actually made from the formula (20). 332 On Jacobi’s Figure. of [Nov. 25, Prof. G. H. Darwin. t+a=q faapsod saynsas ay) ayn 02 pappy uaag soy hjvun ayqn) aaogn yp we gng ‘(T—2),-B,ue Lo *(T—2) ‘ot, (ov£) 92 hbsaua onsepaiquy ay Bua ae 10 ‘9°6t,(0uF) sv hbsaua ayauy ayy f rigegus Lo ‘x: ‘ng (045) st umazshs ayz fo wnguamow fo zuamow ayt—'g' N 000- T OF. ece9. GLLG. 068. | PPS. G00¢. ETON; 000: T cpg. VEE. - SO8P.- 6807. POEL. ~ S8TF. COPTP- % “AS10U0T 000. TOT. 6I0T- 7960- 1060. 0280. L180: 9P080- ) ‘OISUTLLJUT) *OLOULT (ea) 9TO-T PPO. 608F- 0268. LOVE. FSIe. 908. FOS. C1808. ‘TUN ULIUTOUE jO “MOT, 000: €10. PEE0- 9890. L¥OL0- 6280- 09060. 860. 60. 99860. ‘ony /- oa ‘Buy "SULO[GOIg 8,1qoovr yo STOTyN[OY 000: T 966. PC86- CPc6: éF06- 89I8- LVg9. 8LV IPG. 0000- “85 C2) 000: 826. V89E- PLOG-: T66S:- L089. 002. F8L- 908 - L9GI8.- (:29) 000: T 966. S86. 6596. 1686 - 2906. 0998. gs. 618: 19218 - (90) "SUOTJOOS JO SOTILOLIZUIIO TT 00- PP: ChrS. ZL09- P6P9- 919. 9169: 969. 869. 1169. ‘e/a 00. 0 cy. 0-¢ 8gs¢. 9ST. € 6102; IVE. 3% TTI8: 668-1 GEc6- 4009. T PSPO-T | L€8é-T €61-T | 6246-1 641-T | 912-1 GL6L- TL | G461-T “6/9 ‘soxY ‘e/p ,06 sP8 461 98 GL eh £9 OF FS FS OF 486 TFL 9. 0 0 06 ~¢88 c8 708 08 ry 8 GL CL FL OL 6L ¥9 r g9 he Gite. O09 pia Lg E41 cc 0-0 LG 16 ¥S / ° Mt / co) the L ‘sopsue Arerixny 1886.]' . Equilibrium for a Rotating Mass of Fluid. - 333 then by trial and error to find two values of « one degree apart, one of which made the left-hand side of (28) positive, and the other negative. The smallest value of y is 54° 21’ 27”, but after that value integral degrees for y were always chosen. The solutions for y=55° and 57° could not be found very exactly from the elliptic integrals with logarithms: of only seven figures, but the solutions were confirmed by the approximate formule (21) and (22). The solution for y=80° was confirmed by the approximate formule (23) and (24), and that for y=85° was only computed therefrom, since when y=80° the approximate formula gave nearly identical results with the exact one. The solution obtained is embodied in the table opposite. The first three columns give the auxiliary angles y, «, 8, from which the remain- ing results are computed. As a graphical result is much more intelligible than a numerical one, I have given two figures, showing the three principal sections in two cases, namely, where y=60°, and y=75°. For these figures a is. taken as 2 cm., so that the volume of fluid is #7 x 23 cubic cm. 334 Prof. G. H. Darwin. On Jacobi’s Figure of [Nov. 25, 6072 (t= 2-346 It will be noticed that the longer the ellipsoid the slower it rotates. It is interesting to observe that while the angular velocity continually diminishes, the moment of momentum .continually increases. The long ellipsoids are very nearly ellipsoids of revolution about an axis perpendicular to that of rotation. Thus in fig. 2 the section through b and ¢ is not much flattened. The most remarkable point is that there is a maximum of kinetic energy when a/a is about 3, or when the length of the ellipsoid is about five times its diameter. However, notwithstanding this maxi- mum of kinetic energy, the total energy always increases with the length of the ellipsoid. _ The kinetic energy is the product of two factors, one of which always increases, and the other of which always diminishes; thus it is obvious that it must have a maximum. The result was, however, quite unforeseen, and it seems worth while to obtain simpler formule for the case of the long ellipsoids. This may be done by taking as the parameter a/a, or the length of the ellipsoid, instead of y. From the table we see that in the later entries $8 is very nearly 1886. ] Equilibrium for a Rotating Mass of Fluid. 339 equal to y, and that « becomes very nearly equal to 90°. Hence we may put a=90°, and B=y. Thus, approximately, o (sec 8 sec y)s== (sec y)8 a and cos r=(2); y=3r—(2). a a The axes of the ellipsoid are ay ( a3\t , _—_ 9 —— ° a a Now if in formula (24) we only retain the oe powers of tan ¥, we have w sinycosy[ 1 ] AS Poa ist —= _—— og.cot (g7—sy)—# Aro - tany = G31) —3 si get =F" slog.cot (4741) —sin y |. But — sin ¥ log.cot (¢7—3y) =log, ae ee +3 log. Therefore writing 1—2Zlog,2=C, so that C=0°3573, we have If we put a/a=5'042, this formula gives w?/4z7o=0°01264. The full value in the preceding tables was 0'0131; thus even with so short an ellipsoid as this, the results agree within 4 per cent. With rougher approximation we have of which the limit, when a is large, is zero. For the moment of momentum we have = F we \F in == (see B sec y)#(1 + cos*B) (=) =z; “(+5 =;)(tog f°) 336° Ona Rotating Mass of Fluid. . - [Nov. 25, or, with rougher approximation, - “= sal; Yoeth of which the limit is aie: 1 2 Again, aes =) “) a ae | ad Now the function | (log. — C ) has a maximum, when log—=1 +C =1:3573, that is when -=1-696. On comparison with our tables it is obvious that the approximation is bad, and that the true solution for a maximum is considerably dif- ferent from the above. Nevertheless this investigation shows that there is actually a maximum of kinetic energy. ., Since F=log,cot (47—4y) =2 E= = log. | , we have : es AKEOS Bi COs Dp ane a t=l- “ayes Yay F=1—4(> [togc+ § log |. If we like we may express these several results in terms of the minor and major axes of the ellipsoid, for b=c= = and therefore a ae=ca. | alt . Thus . a 8 8d 46] 1886.]. Dynamical: Theory of the Tides of Long Period. 337 IV. “On the Dynamical Theory of the Tides of Long Period.” By G. H. Darwin, LL.D., F.R.8., Fellow of Trinity College and Plumian Professor in the University of Cambridge. Received November 5, 1886. In the following: note an objection is raised against Laplace’s method of treating these tides, and a dynamical solution of une problem, founded, on .a paper by Sir William Thomson, is offered. and 7 sin @ be the displacements from its mean position of the water occupying that point at the time ¢, let ) be the height of the tide, and let e be the height of the tide according to the equilibrium theory ; let n be the Oyoular velocity of the earth’s rotation, g gravity, a the earth’s radius, and y the depth of the ocean at the point 8, ¢. | Then Laplace’s equations of motion for tidal oscillations are— a ae —2nsin 9 00807 = ae e) ] dt? dt ado dy dg d ee ea bMS | sino +21 008 OFF qe aan oad) And the equation of enaaltinctle 1s— | 7 ie ha ign saacesinty=0. 2. The only case which al be considered here is where the depth of the ocean is constant, and we shall only treat the oscillations of long | period in which the displacements are not functions of the longitude. As the motion to be considered only involves steady oscillation, we assume— e=ecos(2nft+a) ) b = hcos (2nft-+2) B= woos Onprt a) Os i Mon. GD se gin (ore a | u=h—e J Hence, by substitution in (1), we have | 1 du 2 0 ije—= na See af? +yf sin 0 cos ae Wa O+ af cos 0=0, Let 0, ¢ be the colatitude and longitude of a point in the ocean, le ae 338 | Prof. G. H. Darwin. On the [Nov. 25, where iss ee g 1 du a 2 ——— —-) W hence «( f*?—cos?6) EAT : 1 cos 0 du De Q = — ——_ —-e y sin 0( f?—cos*0) dn fae Then substituting for # and y in (2), which, when y is constant and » is not a function of ¢, becomes yt id ; mi ha eae aot sin 0) ==(0) y d@ [sin@du/de sin 6d@ _ f*—cos®6 we get ] +4ma(u+e)=0. This is Laplace’s equation for tidal oscillations of the first kind.* In these tides f is a small fraction, being about 3; in the case of the fortnightly tide, and e the coefficient in the equilibrium tide is equal to H(4—cos*6), where His a known function of the elements of the orbit of the tide-generating body, and of the obliquity of the ecliptic. If now we write B=4ma/y, and ~=cos @, our equation becomes d i 2 du 9 oS = Blut HQ—)1. . . . . @ In treating these oscillations Laplace does not use this equation, but seeks to show that friction suffices to make the ocean assume at each instant its form of equilibrium. His conclusion is no doubt true, but the question remains as to what amount of friction is to be regarded as sufficing to produce the result, and whether oceanic tidal friction can be great enough to have the effect which he supposes it to have. The friction here contemplated is such that the integral effect is represented by a retarding force proportional to the velocity of the fluid relatively to the bottom. Although proportionality to the square of the velocity would probably be nearer to the truth, yet Laplace’s hypothesis suffices for the present discussion. In oscillations of the class under consideration, the water moves for half a period north, and then for half a period south. Now in systems where the resistances are proportional to velocity, it is usual to specify the resistance by a modulus of decay, namely, that period in which a velocity is reduced by friction to e! or 1+2°783 of its initial. value ; and the friction contemplated by Laplace * * Mécanique Céleste.’ 1886.] Dynamical Theory of the Tides of Long Period. 339 is such that the modulus of decay is short compared with the semi- period of oscillation. The quickest of the tides of long period is the fortnightly tide, hence for the applicability of Laplace’s conclusion, the modulus of decay must be short compared with a week. Now it seems practically certain that the friction of the ocean bed would not much affect the velocity of a slow ocean current in a day or two. Hence we cannot accept Laplace’s hypothesis as to the effect of friction. We now, therefore, proceed to the solution of the equation of motion when friction is entirely neglected. The solution here offered is indicated in a footnote to a paper by Sir William Thomson (‘ Phil. Mag.,’ vol. 50, 1875, p. 280), but has never been worked out before. The symmetry of the motion demands that wu, when expanded in a series of powers of mw, shall only contain even powers of pm. Let us assume then ee ate ; pe—f? Gn buet Bub ar leprae iio) os eee ee Then 1—p? du 3 aie ee ; B eek %+) ep ahi Biu+(B, By) pi + . +( 2i-+1 By; De amie ad Tl—npn?2 du . a, =B,+3(B,—B)pe+ ... +(2t+1) (Bains — By) wit (5) Again ad ion —f? By t+ (b,—f cul 3) JU a ica OP Tee eet Megl op PE) Pele i 0-4 pPBY+4(By—f°By)uh+ tos +5 (Bus —f? Boa) w+ (6) where CO is a constant. Then substituting from (5) and (6) in (4), and equating to zero the successive coefficients of the powers of », we find, C= —3H+ B/p ay —B,(1—2,f°8) + 46H = 0 | Seri ae. win f*8)— ai (i za en Sek, SS = 0 | 340 oo PpofGl A. Darwim.~~On the > [Nov. 25, Thus the constants O and B;, B;, &c., are all expressible in terms of B. | We may remark that if —%-3-PB_4{=3BE, or B_=—2H, then the general equation of condition in (7) may be held to apply for all values of 7 from 1 to infinity. Let us now write it in the form— Poissy a oh Aba When 1 is large, B,;,,/B,;, either tends to become infinitely small, or it does not do so. Let us suppose that it does not tend to become infinitely small. Then it is obvious that the successive B’s tend to become equal to one another, and so also do the coefficients B,,_,—f?B,,, in the expression =1— accor B+ aati SOW, es) for du/dpm. Hence alt ic where LI, M are finite, for all values of up. fh du ., See r iat ae (2 Hence aa —LY\— 2 +——— — and therefore 2 is infinite when w =1 at the pole, and dé/dt is infinite there also. Hence the hypothesis, that B,;,,/B,,, does not tend to become infinitely small, gives us infinite velocity at the pole. _But with a globe covered with water this.is impossible, the hypothesis is negatived, and B,;,,/B;-, tends to become infinitely small. This being established let us write (8) in the form— it ‘g a — By-4 : ESN S => ae Pep ee By; 3 La) Po Oe Pa Ps (9) By repeated applications of (9) we have in the form of a continued fraction Bel > amie | Saar be EEENEE yi 8 [+&e. Sain] 2 Sa Late ae Brg ae Twa J B 1—aeeyl P 1—Tao 8 (10) And we know that this is a continuous approximation, which must hold in order to satisfy the condition that the water covers the whole globe. Let us denote this continued fraction by — Ni. Then, if we remember that B_|=—2H, we have By B,=2EN,, a= —Np, a +Nsz, &e., 1 3 -1886.] Dynamical Theory of the Tides of Long Period. B41 so that | ar aS B = OnN.N,, 5.— —2HN,N,N3, By= —2HN,N,N3N,, &e. and C= 40+ 22k, is Then the height of tide } is equal to 2 cos (2nft+a), the equilibrium ia e is equal to H(4—p?) cos (2nft+«), and we have h=u+ (Zp) | =C+ ae +3 f° By)u? +4(B —f?Bs) ut +g Bs—f?Bs) ng + 2 OAT. 2 2 Fa TPN) +N TPN ANNA + PNG) Hot Now when B=40, we have Y=zo X 4ma= 7 4= 7260 feet; so that B=40 gives an ocean of 1200 fathoms. With this value of 8, and with f=-0365012, which is the value for the fortnightly tide, I find , | N,=3°040692, N,=1:20137, N,='66744, N,=-42819, N;, ='29819, Ng= °21950, N,= ‘16814, Nz="13287, Nj=107, Nyp="l, &e. ' These values give . 3 1= "15203, 14/2M,=1-0041, 4 EN,(1+f2N,)=1-5228, LN\No(1-+f2N,)=1:2187, «ANN, (1+2N,) "6099, aN, ... N4/2N,)=-2089... 2M) od (142, ) 0519, IN, ... N,(1+f2N;)="0098, 3N,... Ni(14+f2N,)=0014, LN, ... Na(1+f2N,) = 00017, &e. So that h ap = 15201-00412 + 152284 121878 + 60998-20890 + 05191? —-0098u'4 + -0014u16—-0002u18+4 . At the pole, where pol, the equilibrium tide is ere at the equator it is +12. Now at the ae h=—Hx:1037=—3H x 1556, and at the equator h=+HxX'1520= 43#x:4561. In a second case, namely, with an ocean four times as deep, so that 6 =10, I find 342 Dynamical Theory of the Tides of Long Period. [Nov. 25, 4, = 23631-0016 .2+ 5910p —"1627p8 + 02588 —-0026u19 + 000212 At the pole h=—Hx°31387=—2E x'47], © at the equator h=+Hx:2368=+4H x :709. With a deeper ocean we should soon arrive at the equilibrium value for the tide, for N,, Nz, &c., become very small, and 2N,/8 becomes equal to 4. These two cases, 8=40, 8B=10, are two of those for which Laplace has given solutions in the case of the semi-diurnal and diurnal tides. We notice that, with such oceans as we have to deal with, the tide of long period is certainly less than half its equilibrium amount. In Thomson and Tait’s ‘Natural Philosophy’ (edition of 1883) I have made a comparison of the observed tides of long period with the equilibrium theory. The probable errors of the results are large, but not such as to render them worthless, and in view of the present investigation it is surprising to find that on the average the tides of long period amount to as muchas two-thirds of their equilibrium value. The investigation in the ‘ Natural Philosophy’ was undertaken in the belief of the correctness of Laplace’s view as to the tides of long period, and was intended to evaluate the effective rigidity of the earth’s mass. The present result shows us that it is not possible to attain any estimate of the earth’s rigidity in this way, but as the tides of long period are distinctly sensible, we may accept the investigation in the ‘Natural Phiiosophy’ as generally confirmatory. of Thomson’s view as to the great effective rigidity of the whole earth’s mass. There is one tide, however, of long period of which Laplace’s argu- ment from friction must hold true. In consequence of the regression of the nodes of the moon’s orbit there is a minute tide with a period of nearly nineteen years, and in this case friction must be far more important than inertia. Unfortunately this tide is very minute, and as I have shown in a Report for 1886 to the British Association on the tides, it is entirely masked by oscillations of sea level produced by meteorological or other causes. Thus it does not seem likely that it will ever be possible to evaluate the effective rigidity of the earth’s mass by means of tidal observa- tions. 1386.] Presents. 343 Presents, November 18, 1886. ‘Transactions. Adelaide :—Royal Society of South Australia. Transactions and Proceedings and Report. Vol. VIII. 8vo. Adelaide 1886. The Society. Amsterdam :—Genootschap “‘ Natura Artis Magistra.” Bijdragen tot de Dierkunde. 13e Aflevering. 4e Gedeelte. 4to. Amsterdam 1886. Baltimore :—Johns Hopkins University. Circular. Vol. V. Nos. 50-51. 4to; Studies from the Biological Laboratory. Vol. III. No. 7. 8vo. Baltimore 1886; Studies in Historical and Political Science. Fourth Series. Nos. 6-10. 8vo. Baltimore 1886; Register, 1885-86. 8vo. Baltimore. The University. Medical and Chirurgical Faculty of Maryland. Transactions. 88th Session. 8vo. Baltimore 1886. The Faculty. Peabody Institute. 19th Annual Report. 8vo. Baltimore 1886. The Institute. Basel :—Naturforschende Gesellschaft. Verhandlungen. ‘Theil VIII. Heft 1. 8vo. Basel 1886. The Society. Batavia :—Genootschap van Kunsten en Wetenschappen. Notulen. Deel XXTV. Aflevering 1. 8vo. Batavia 1886. The Society. Berlin :—Ko6nigl. Akad. d. Wissenschaften. Abhandlungen. 1885. Ato. Berlin 1886. The Academy. Birmingham :—Mason Science College. Calendar, 1886-87. 8vo. Birmingham 1886. The College. Bombay :—Natural History Society. Journal. Vol. I. No. 3. 8vo. Bombay 1886. The Society. Boston :—American Academy of Arts and Sciences. Memoirs. Vol. XI. Part 4. No. 4. 4to. Cambridge 1886; Proceedings. Vol. XIII. Part 2. 8vo. Boston 1886. The Academy. Brussels :— Académie Royale de Médecine de Belgique. Mémoires Couronnés et autres Mémoires. 8vo. Tome VIII. Fasc. 1. 8vo. Bruxelles 1886. The Academy. Musée Royal d’Histoire Naturelle de Belgique. Bulletin. Tome IV. Nos. 2-3. 8vo. Bruwelles 1886. The Museum. Société Royale Malacologique de Belgique. Annales. Tome XX. 13°68 | 99°60 | 9°183 0°0328 a 12°80 | 99°75 | 0-185 | 0-0328 . 14°16 | 99°82 | 0°182 0 -0328 Mean....| 14° 100° 2 00328 Lead.—Pure, cast. W. t. to. w. Sp. h. Other observers. 89-508 ....| 16°70 | 99°85 | 0-428 | 003091 | Regnault...... 0°0307 » vee | 16°34 {100-04 | 0°481 | 0-03093 ys oe gael ae he a Kopp .i..'...-, On@eis Mean....| 16° 100° oie 0 03092 * Received from Professor Reynolds. On the Method of Condensation in Calorimetry. 359 Some diversity of result exists among the determinations by other experimenters. Probably much of this diversity is to be ascribed to actual difference in the molecular condition of the samples operated on. The veracity of the present method must be judged then by general agreement with previous observations. In the case of zinc, however, the most reliable observations are probably those of Bede, Bunsen, and Regnault. The first of these observers, it will be re- membered, extended his observations to the variations in the specific heat of zinc with change of temperature limit.* From those ohserva- tions the value for the mean calorific capacity between 10° and 100° is deduced as 0:09412.- This is identical, it may be said, with the value found by the method of condensation. Compare, also, in this list of experiments on zinc—and throughout the table—the variations of temperature interval, sufficiently revealed in the varying values of #,°, with the delicate compensating variations in the weights of condensed vapour, resulting in the close agreement of the values deduced. It will be seen too that among the five results on zinc the extreme variation from the mean amounts to no more than 0°17 per cent. The experiments on aluminium, silver, and platinum tax more severely the consistency of the experiments, owing to the limits of accuracy imposed by the balance. Of the experiments made on aluminium, one is not recorded owing to a doubt about the accuracy of the initial temperature coupled with an abnormal result. The mean finally arrived at agrees with Mallet’s experiments effected in Bunsen’s ice calorimeter. This value accords better with Dulong and Petit’s generalisation than the lower values of Regnault and Kopp. In the experiments on silver, much care had to be taken in esti- mating the value of w. No bucket was used, the specimen being looped in a fine platinum wire, the small quantity of water precipi- tated adhering to its surface. It is the smallest condensation I have attempted to deal with. ? The series on platinum were some of the earliest effected by the method, and that in a very rude form of the apparatus. Two of the first experiments are not included in the list. As, I think, some import may fairly be attached to consistency in experiments where prevailing conditions vary, I quote for comparison the extremes of Regnault’s experiments on metals I have dealt with. Platinum ....+. 569 grams 7 experiments.. 0°03223—0-03279 LG Ope ee ZA eh 3 3 .. 0°09528—0-09589 UC ie aa sh «3 1. 345, 5 Pe .» 0°05679—0-05739 LC ie noe I260 53 3 ‘, -- 0°03129—0-03150 * “Mém. Couronnés de l’Acad. de Bruxelles,’ vol. 27, 1856. + ‘Chemical News,’ vol. 46, 1882, p. 178. VOL. XLI. 28 360 | Mr. J. Joly. If these be compared with the extremes contained in the table it will be found that, except in the case of silver, the comparison is fayvour- able to the method of condensation. At the suggestion of Professor Fitzgerald, experiments on distilled water sealed in glass envelopes were undertaken. It appeared probable that the specific heat of this substance, as obtained in experiments made ona very large scale by Regnault, would afford more reliable data for comparison than metallic solids, in the ease of which too it is likely that differences in molecular freedom may exist affecting the calorific capacity to a considerable extent. Again it was easy to obtain this substance sufficiently pure with facility. The experiments were carried out as follows :— A very thin glass bulb is blown before the blowpipe. Its capacity is to be some 15 or 20 c.c. In drawing off the tube, a little hook is left for conveniently suspending the bulb in the calorimeter. It is sealed by closing the extremity of the hook; but before doing so we see that no appreciable quantity of moisture is enclosed, introduced from the breath in blowing it. If moisture is visible it is expelled by repeated heating and cooling, the cooling finally being effected several times in a desiccator. Neglect of this caused appreciable error in some of my experiments; it was ultimately detected in the abnormal specific heat ascribed to glass by the initial experiments on the envelope. It is probable that this trace of water, as suggested by Professor Fitzgerald, and contrary to my original idea when ignoring it, acts more by its latent heat of vaporisation than by its specific heat. To ascertain the amount of precipitation to be allowed for this envelope, it is hung from a wire loop between the stirrups of the carrier, so that condensation falling from it is received in the bucket beneath. The total condensation for bulb and carrier together with that due to the air contained in the bulb, including also the effect of displace- ment difference from air to steam, afford— . Ly, =O TTS. eb g Range, 11:0—100°35° ( 1 oe C22) 0, OG: apie Ghee Range, 11-°3—100°35° The bulb is now opened by removing the extremity of the glass — hook, and weighed = 2:84 grams. The height of the barometer (760) and temperature (11°) are noted. The next operation is to fill it with distilled water. This is effected under the receiver of the air-pump by exhausting while the orifice of the bulb is submerged, and again cautiously exposing to atmospheric pressure. A space is left unfilled to allow for subsequent expansion. The contents of the bulb are now raised to boiling point by immersing in a bath of boiling water, and it is sealed with the blowpipe while at this temperature. This is necessitated by the thinness of the On the Method of Condensation in Calorimetry. 361 glass; it was found that such bulbs will not stand the internal pressure otherwise obtaining at steam temperature. Its weight is now 15°930 grams. It is estimated that its content is altogether 16°5 c.c.; this quantity of air at 760 mm. and 11°, as above, weighs very closely 0°020 gram. The deduction for the weight of the glass envelope in order to deduce the weight of con- tained water is, then, 2°084—0-020 affording W=13°866. In subsequent experiments with this bulb of water, it is necessary from the precipitation obtained to deduct w, as ascertained by experi- ments (1) and (2), above, diminished however by the quantity of precipitation to be ascribed to the calorific capacity of the contained air present in those experiments. Taking the specific heat of air as 0°2389, this retrenchment calculates to be nearly 1 mgrm. of precipi- tation, and it is taken as such as it probably contained. still some moisture. This leaves the deduction as 0-115 fora range of 89:2”. Although the nearly constant displacement difference of the bulb from air to steam is here included, this quantity may without sensible error be recalculated for variations in temperature range as the cor- rection on the large condensations subsequently obtained. The further process of experiment is the same as previously described in the case of zinc. In this way, the six experiments contained in the following table have been carried out :— Table of Experiments on Distilled Water. No. W. i Se r. W. Sp. heat. i 13 °866 11°20 49-30 536 °56 2°3125 1 -0087 2 ‘ 11°70 99°45 | 536°90 | 2-2760 | 1-0044 3 : 8 80 99°55 | 536°80 | 2°3610 | 1-0074 4 oS 9°70 99 -50 536 ‘80 2 °3320 1 -0055 5 4s 9°47 100-00 536-50 2°3530 1 -0055 6 58 8°80 100-10 536 °40 2°3740 1°0059 Mean ..| 10° 100° ae ate 1 -0062 Between same limits, according to Regnault, specific heat = 1-°0055. The last four experiments in the table were carried out in such a way that the rate of precipitation was much retarded, in fact the conditions were altered to those prevailiug in the case of a very badly conducting body. This was effected by shielding the glass bulb from direct contact with the steam by a loose fitting copper-foil box, an intervening air-jacket being left around the bu!b. With this arrange- ment precipitation was hardly completed in 15 minutes; the naked 2B 2 362 | Mr. J. Joly. bulb was quite heated in something less than four. A deduction was of course made for the shield by preliminary experiments. I would point out that any error in Regnault’s estimate of the increase of specific heat of water with rise of temperature will militate in a double sense against the agreement of his results with mine. For this increase is assumed by Regnault in deducing, from his formula for the total heat of steam, the heat of evaporation, and, as it is subtractive, an error on the side of excess in his estimate of the specific heat of water introduces an error on the side of insufficieney in the value ascribed to \, and vice versé. Thus not alone would the quantity with which I compare my results be erroneously assumed, but in proportion as error exists in its value, error in the opposite direction would be introduced into my results. I add some experiments bearing on questions of radiation error as affected by extent and nature of surface exposed to the steam. They are from those made on minerals, and are embodied in a paper on the specific heats of minerals. (‘ Roy. Soc. Proc.,’ vol, 41, p. 250.) The following table contains cases where experiments were re- Table I. | Wi. W. ty. t,°. |Sp. heat. Limpid crystal of Barites ....| 76°109 | 1°405 9°65 | 100°30 | 0+109238 A eee te ne Same im small | bes-143 | 1-195 | 9-60 | 99°80 | O-loa10 PCASTOTIGS /ae\cleta aie ei lepete ete Rhombohedron of Iceland spar| 33°904 | 1°156 | 10°00 | 99-76 | 0°20383 Same in small fragments...... 33059 | 1°079 | 18°34 | 99°50 | 0°20345 Specimen of Zale in one piece..| 47 °445 | 1°685 | 12°32 | 100-25 | 0°21671 Two Sagments from same hand: |\ 44-681 | 1-568 | 18-30 | 100-20 | 0 -21686 SPECIMEN), a.s/5 5.0 Lis aie Gb cisi- jes | Specimen of Lepidolite — one \ 49°47 PIECE se veeeeeseseeeneenes Two pieces from same hand- \ 48 26 | 1°470 | 12-20 | 100°20 | 0°20978 *823 | 1°676 | 12°38 | 100°20 | 0°20967 BPCCIMEN «2 00s aineae sees een Five crystals of Amphibole ....| 57°192 | 1°835 | 12°00 | 99°72 | 0°19634 The two largest of the five ....| 45°183 | 1°443 | 12°94 | 100°30 | 0°19635 The three largest of the five ...| 51°309 | 1°640 | 12°90 | 100-30 | 0°19619 hed milkewhite Ol" | Las-o74 | 1546 | 12-60 | 99-10 | o-19974 Pieces from same hand-specimen| 41°829 | 1°366 | 11°60 | 99-40 | 0°19967 Flakes of Biotite ............| 20°291 | 0°685 | 12°63 | 100-30 | 0°20651 Part of same.........00s0-+-| 177809 | 0593 | 12°70.) 99-95 1 mene Crystal of Muscovite ......... 20°541 | 0°687 | 12°40 | 99-90 | 020519 Toose Hace trom same hand: | L2s-7s5 | 0-778 || 18-80 | 99-75 | Omzndae BPC CRINGM. is\2's o's iais ioe seins On the Method of Condensation in Calorimetry. 363 peated under very different conditions of surface area. It is evident from them that the extent of surface exposed by a substance to the steam affects the result only in a very trifling degree; the repeated consistency can hardly be the result of chance. As liability to radia- tion errors will increase, ceteris paribus, with extent of surface, they reveal, I think, that the method is not open to appreciable error from such sources. - Table II illustrates, in the cases of gypsum, calcite, and aragonite, minerals fairly constant in chemical composition, fidelity to the chemical nature of a substance through varying conditions of weight, bulk, shape, and surface texture. Table IT. W. W. ty”. t,. | Sp. heat. Hydrous calcium = sulphate.. Gypsum :— Clear crystal of selenite ....| 21-048 | 0-965 | 10-00 | 100-10 | 0-27264 Four clear crystals of selenite | 13°204 | 0°623 | 7°24 | 100°40 | 0°27164 Fibrous silky gypsum ....| 30°150 | 1°393 | 9°20 | 100°40 | 0:°27167 Fragments of rough white ‘| fs 547 | 1°456 | 9°98 | 100-40 | 0-27374. SUR Gono qenpumododo Calcium carbonate — Calcite, rhombohedral :— Iceland spar, limpid erystal..| 33-904 | 1:156 | 10°00 | 99°76 | 0-20383 Milk-white rhombohedron...| 35°815 | 1°135 | 16°75 | 99°93 | 0°20489 Three slender hexagonal | | 15.944 | 0-329 | 18-04) 99-60-| 0°20340 crystals, limpid ........... f ea. EEN re “| ft 524 | 1-075 | 11-90 | 99-50.| 0 -20908* White chalk, in fragments. . 22°454 | 0°747 | 12°30 | 99°80.| 0°20415 White chalk, fragments roan I 21 7397 a) ‘706 13 77 99°35 | 0-20390 same specimen .........4. Calcium carbonate—Aragonite, orthorhombic :— eo bras pareny Crys: boa ‘331 | 0:806 | 12°45 | 99-65 | 0-20401 Two limpid crystals ........| 28°161 | 0°934 | 11°60 | 99-00 | 0°20393 Apart from experiment, I think sufficiently careful consideration shows that we might expect very considerable accuracy from the method. ‘There is theoretically, it will be found, but one source of error needing serious consideration; it is the danger of precipitation occurring, not on the surface of the substance, but at points close to * For a brief notice of such abnormal cases see my paper “On the Specific Heats of Minerals,’’ ‘ Roy. Soc. Proc.,’ vol. 41, p. 250. 364 Mr. J. Joly. the surface; in other words, the formation of mist by radiation from the steam to the cold substance. Now it is assured that on the replacement of air by steam a film of water is instantaneously deposited on the surface of the substance, and, assuming an abundant supply of steam, condensation then pro- ceeds as fast as heat is transferred by conductivity and diffusion across this film to the cold surface of the solid beneath. Whi'e then we must assume that the inner surface of the film is appreciably at the temperature of this cold surface, it is probable that we may also assume the outer surface of the film to be throughout the experiment nearly at the temperature of the steam. There can be but little difference, for fall in temperature is made good with great rapidity by fresh condensation. There is here in the first place a favourable condition, as surface radiation can, under such circumstances, be but insignificant in amount, and radiation from points in the surrounding steam can only be supposed as affecting points within the film or, in — some cases, within the substance. Only in this way can we suppose the formation of precipitation elsewhere than at the very surface of the film by actual contact. But again, the opacity of water to radia- tion from aqueous vapour will here afford protection. This opacity, it will be remembered, has been shown by Tyndall and others to be very great. Thus I find that Tyndall records among his experiments that a layer of water but 0°07 of an inch in thickness transmitted but 1:1 per cent. of the radiation from a hydrogen flame. It may be supposed that the more perfect accord between the vibration periods of radiator and absorber obtaining in the calorimeter will ensure greater, if not perfect, opacity. The contact precipitation, consequent on the loss of vis viva of the impinging molecules—the film transmitting the energy to the sub- stance—insures that there will be many molecules entering and few leaving, and hence extension of free path or diminution of pressure in directions normal to the surface of the substance. There is then super- added as a protective element a converging drift of steam upon the sub- stance, tending to restore to it what precipitation may possibly be due to radiation. Under perfect conditions of steam supply—could we suppose, for example, the substance, in a chamber which could be supplied with steam from so many points that we might substitute the idea of an unlimited region of steam suddenly brought around it —this drift, I think, excludes almost the possibility of error supposing radiation. In attainable conditions, where cross draughts will prevail to some extent, there would still evidently be protection involved in the very fact of condensation. , There are, then, three circumstances tending to nullify this error; the high temperature of the external surface, the adiathermanous nature of the water film, and the converging drift of steam. Whether On the Method of Condensation in Calorimetry. 365 all three act, or whether the first two are not practically efficacious of themselves, I think that theory is here in accord with experiment in showing that on this count no appreciable inaccuracy is to be appre- hended. There are a few other considerations. From the facts that there is a fall of temperature across the film, the gradient descending nearly to the temperature of the substance on the’one side, and that through- out the period of condensation the film continually gravitates down- wards as it receives accretion from without, it might be expected that water which had not yet risen to steam temperature might in some cases reach the bucket. This occurs, but need obviously be no source of error. If experiments be made in glass calorimeters, the formation of a dew on the underside of the bucket will often be noticed; to this extent it does no harm. But in the case of sudden and copious precipitation, especially in the case of smooth substances, where water runs off more freely at points close to the surface of the body, the precipitation on the outside of the bucket may collect in such quantity that drops fall off. I have occasionally noticed this, and it should be borne in mind; but with the flat form of bucket used, and the safe- guard afforded by the supporting claw, there is little danger of this occurring up to rapid precipitations not much exceeding a couple of grams. Over that amount a second catchwater, which may be of small dimensions, should be provided beneath the claw. The substance hanging in the steam is safe from radiation errors. The phenomena attending accretion of weight terminate in the con- ditions which prevail in the case of a liquid in presence of a saturated atmosphere of its own vapour, the whole maintained at constant temperature and pressure, when the relative weights of liquid and vapour remain constant statistically, and absolutely so far as we can measure. If radiation from the hot substance to the cooler walls of the calorimeter occurred, constancy of weight would not be attained. Jt is certain that the least radiation across the steam-jacket would be revealed in continued slow accretion of weight. But there is nothing so striking in experiments effected by this method as the steadily maintained equilibrium of the balance once the substance has attained the temperature of the steam, the pointer vibrating with perfect equality so long, apparently, as we chose to prolong the experiment. If the steam supply be cut off for a moment there is loss of weight, and on restoration of steam there is finally on the whole gain of weight, for radiation, as well as evaporation, occurs in the absence of steam. If the pressure be appreciably increased by throttling the exit pipe and partially closing the boiler for a couple of seconds, the balance reveals increase of weight; but so long as the pressure is neither increased nor diminished equilibrium is absolutely preserved. _ It is obvious that disturbing effect due to water-dust or mechanically 366 Mr. J. Joly. suspended water in the steam is negatived by this constancy of weight. Probably such dust is all deposited in the steam pipe shortly after leaving the boiler. Mist or water-dust doubtless is present at first, due to the condensa- tion produced in heating up air in the calorimeter. Some of this is thrown upon the substance, but this will be small in quantity, probably inappreciable, and acts against what error is due to radia- tion from the incoming steam to the substance. This last is an error analogous to the error of transference in other methods, but with easily attainable rapidity of air displacement probably far less. The degree of accuracy attainable in effecting the measurements remains to be considered. Of these, it is evident that in obtaining ~ the temperature limits great accuracy is attained by the use of thermometers of no extraordinary sensitiveness. If ¢,° and #,° are reliable to ~5 part of a degree, over a range of 80° we are observing to s45 part the quantity to be measured. As regards the observation of w, the weight of water condensed, obviously the degree of accuracy attainable depends on the sensitive- ness of the balance and the magnitude of w. It is also necessary, however, to consider in some detail how far it has been found possible to perfect the mechanical conditions attending the observation of the weight of the substance while immersed in steam. It is evident in the first place that as regards the danger of intro- ducing error into the equilibrium of the balance by heat radiating to its parts, the difficulty may at once be got over by arranging things so that the calorimeter is outside the balance case, as beneath it, the balance standing on a shelf, suppose, and a wire taken down through apertures in balance floor and shelf. In the form already described, indeed, I have detected no error due to unequal heating of the beam, although I have frequently looked for it by unhooking the substance during experiment and testing for want of equilibrium. This is due to the protection afforded by the non-conducting material of the tunnel. It was necessary, however, to retain but one pan, as heat conducted by the rails through the floor of the calorimeter set up a draught tending to draw up the pan. I have detected no error, measurable by the balance, due to con- densation on the wire for suspending the substance, where it issues from the calorimeter. If this wire be closely observed it will be seen that a little bead of water forms on it just above the mouth of the aperture, and although occasionally reinforced by another little bead slipping down to it, it soon reverts to its original bulk, probably by evaporation promoted by heat conducted along the wire. With the size of wire used—about 0°15 mm. in diameter—I do not think this bead of water ever exceeds half a milligram in weight, and, as I say, the balance shows no sign of any gradual increment of weight. This On the Methad of Condensation in Calorimetry. 367 experiment on the constancy of weight has been extended to over half an hour on many occasions. The use of plaster of Paris in forming the aperture avoids what uncertainty and want of sensibility would be introduced into the weighing by water permitted to accumulate in the orifice. Until this plan of cutting the aperture in a bibulous material was resorted to, the accumulation of water gave much trouble. The plaster remains dry when in use for an indefinite time, and wears well. That now in the calorimeter has served through more than 300 experiments. Itis also very easily renewed. In order to avoid as far as possible escape of steam up the wire and ensure constancy of pressure, I have lately adopted a plan which acts automatically in keeping the calorimeter full of steam sensibly at atmospheric pressure. The arrangement consists in locating the escape valve of the boiler at a level so much below the level of admis- sion into the calorimeter, that a small and constant pressure—due to the levity of the steam—is established, urging the gas to ascend the tube leading to the calorimeter. This end is secured by affixing the escape-valye to the end of a wide tube which is taken from the boiler bent twice at right angles and carried down to a level outside the boiler sufficient to secure the requisite pressure; a couple of deci- metres “head” will in general be sufficient. The effect on the weighing of steam draught within the calorimeter can be entirely avoided by shielding or jacketing. In the form already described, indeed, it seldom gave trouble, but in this respect I have in a recent form improved the apparatus. It is worthy of notice, also, that the conditions prevailing when we weigh a substance at a temperature different from that of the air within the balance case do not obtain here, the substance in the calorimeter being surrounded by an atmosphere at its own temperature. Description of an Improved Gravimetric Calorimeter. I have designed an apparatus intended to carry out such conditions as have suggested themselves as conducing to accuracy and to ready working. Its advantages have already toa great extent been prac- tically tested in a recently completed instrument, but this instrument serving itself to suggest improvements is not the same as that now described. Plate 7 shows a vertical section and plan. The apparatus it will be seen consists of a cylindrical chamber with conical ends. This chamber is divided in a vertical plane passing through its axis, the separate halves being firmly hinged on a tripod borne on three adjusting screws. The chamber is thus readily opened by turning back the halves, and closed by pressing them together, when they meet on a ground edge. It is made vf brass and kept as 368 Mr. J. Joly. slight as possible. The half chambers being closed, steam is admitted at the top of the apparatus, the expelled air escaping at the bottom through a tube which passes through the base of the instrument. In plan it will be seen that the steam is admitted by a forked or branching tube at two tubulures, which in elevation are seen to be cut back so.as to afford a ready seat for the supply pipe, and also that the latter when placed in position may conduce to bind closer the half-chambers. The steam pipe is supported further and retained in . position on a light pillar springing from the tripod base. To its seat on this pillar it is clipped by a spring bearing against the centre of the fork, but so that it may readily be laid in its position. A little tubulure is also provided for conveniently taking the temperature by inserting a thermometer.* At other times this tubulure is closed by a little cap (not shown in the drawing).. Two half-cylindrical plugs of plaster of Paris, notched at their meeting faces, serve as before to pass the wire depending from the balance,, which is supposed to rest upon a Shelf placed above the apparatus. Within the outer shell of the calorimeter an inner shield of very slight brass is provided, similar in shape, and capable of a rotational motion of about 60° about its vertical axis.. This is effected by attaching it to a tube which rotates smoothly in the exit-tube at the base of the calorimeter. It is worked by a stud projecting through a horizontal slot cut in the latter. The shield is made in halves, and opens on hinges affixed to the rotating tube. Above, each half of the shield is perforated, so that when in one extreme position it receives within it all the entering steam, but on being rotated 60° no longer admits steam directly, the perforations being then. turned away from the entrance tubulures. When it is desired to close the exit-tube of the calorimeter, a stop is pressed in through a horizontal slot in the tube.. Water condensed from the steam by radiation from the calorimeter is received in a little trough placed beneath the tripod stand. The apparatus is worked as follows :— The carrier being suspended at the right height on the wire from the balance, and the substance being arranged upon it, the calorimeter, with its inner and outer cases drawn. back, is moved under and then closed upon it. The inner case is now rotated so that the calorimeter is thus still further closed, and also one of the apertures of the shield, so placed that a thermometer may be passed through the small tubulure into the interior of the calorimeter. To guard the calorimeter against sudden changes of temperature while the thermometer is assuming * The effect of scale parallax in reading thermometers may conveniently be avoided by bringing the scale into coincidence with its reflection on the mercury thread of the thermometer. The way of’ doing this is easily acquired after a couple of trials. On the Method of Condensation in Calorimetry. 369 the temperature #,°, it is necessary to provide a cover of nonconducting material—as wood—made in halves, and closing so as to permit the reading of the thermometer. When it is desired to carry out the experiment, the forked tube, which is connected with the boiler by 2 or 3 metres of rubber tubing, is separately heated with steam, the valve on the boiler being closed. The thermometer in the calorimeter is then read and withdrawn, the cover removed, and the shield rotated into the position for admitting steam. The steam-pipe is now laid in position; the construction enables this to be done very rapidly and easily. Steam is thus passed directly into the inner chamber at two points, and the inner chamber being very slight condenses but a small quantity of steam, so that the displacement of the air is retarded as little as possible, and is, in fact, with the empty calorimeter almost immediate. On steam flowing out freely at the exit-tube, the valve in the boiler is opened and the calorimeter closed by pressing home the stop in the exit-tube. The adjustment of the wire in the orifice is now effected by the screws on the tripod. LEffected in this way this is a very easy opera- tion, although the orifice may be hardly 1 mm. in diameter and the wire some 40 cm. long. Balance and calorimeter must, however, be steadily supported. The weighing is now begun, and when it is found that the substance is no longer condensing steam, is finished with the shield in the calorimeter in its position for sheltering the substance from draughts. On this operation being completed, the thermometer for taking ¢,° 1s inserted in its tubulure, which is now again over one of the orifices in the inner shield and hence admits the thermometer freely into the calorimeter. Appendix. Corrections for Displacement in Steam. (1.) The substance being counterpoised in air is not when immersed in steam—apart from the occurrence of condensation—any longer in equilibrium with the counterpoise, the density of saturated steam at ordinary pressures being different from that of air. The deduction from the apparent weight cf condensation on the substance is equi- valent to the volume of the substance multiplied by the difference in the weights of unit volumes of steam and air. By the apparent weight of condensation is meant that deduced on subtracting from the weight added to the counterpoise during an experiment the weight due to condensation on the carrier. Let this apparent weight be w,. The difference in the weights of unit volumes of steam at 100° and air at 15° is 0°000636, calculated on the absolute densities of dry air and steam according to Regnault. 370 Mr. J. Joly. The correction on w, is then— —V x 0:000636 gram, where V is the volume of the substance in cubic centimetres. (2.) If extreme accuracy be desired, it is necessary further to reduce the weight of condensation to vacuo. Calling w, the weight deduced after correction (1), the second correction is on w,, and is— + we x 0°000589, the factor 0000589 being the absolute density of saturated steam at 100° (Regnault). It is assumed that we may for the purpose consider unit weight of water at 100° as equal to unit volume. Finally the true weight of water w is very nearly— w=(w,—V X0:000636) x 1:000589. Regarding the factor 0:000636 I may mention thata direct experiment made in the calorimeter afforded 0°00062 as the difference in weight of unit volume of steam at 100°2° and air at 177° and 766 mm. The experiment consisted in hanging a heated sphere of blown glass in the calorimeter—it having been previously counterpoised—and admitting steam before the sphere had cooled to steam temperature. When a sufficient time had elapsed to secure equilibrium of tempera- ture the amount necessary to add to the counterpoise to restore balance was ascertained; this divided by the volume of the sphere afforded the relative density sought.* In the experiment the volume of the sphere was 38°7 c.c., the weight added 0:024 gram. On the Value of X. If the value of be calculated from Reegnault’s formula for, say, the cases of a barometer at 720 and 780, the values 537°2 and 536:0 are obtained; at 760 it is 536°6. In careful experiment this variation must be considered. My practice has been to allow for it by the approximate assumption for ordinary variations of pressure that the — correction on the value of X for the standard pressure 760 mm. is — _+0°7(100—#,°), that is I take A=536°5 +0°7(100—#,°) where ¢,° is the temperature of the steam, read directly by a thermo- meter or deduced—as it conveniently may be and with great accuracy _—from the height of the barometer and reference to Regnault’s tables for the corresponding boiling temperature of water. * See “On some methods of Measuring the Densities of Gases,’ by G. F. Fitz- gerald, F.R.S., ‘ Roy. Dublin Soc. Proc.,’ vol. 4, 1885, p. 481. Proe. Roy Soc. Vol.41,.PL 6. 3 : | CARRIER AND PAN. Proce leoy: 300, VOl.41, PU. 7. Peer le Ener we NOR | VERNER: “TNE ELEVATION SECTIONAL PLAN. West, Newman & Calith, | NOTICES TO FELLOWS OF THE ROYAL SOCIETY. Applications and Reports to be considered at the May Meeting of the Government Grant Committee must be sent in by March 31st. The Library is now open from 11 a.m. to 6 P.M., except on Saturdays, when it is closed at 1 P.M. ‘4 A printed post-card of the papers to be read at each meeting will be sent weekly 4 to any Fellow upon application to Messrs. Harrison and Sons, 46, St. Martin’s Lane, W.C. Ready. Royal 4to. pp. xiv-326, cloth. Price 21s. OBSERVATIONS OF THE INTERNATIONAL POLAR EXPEDITIONS. | 1882-1883. Fort Rak. With 32 Lithographic Folding Plates. Published and Sold by Triibner and Co, LS iat OS May Meni ays SUE Sa Be ae) Laura gS AY ta Welle Soe US ia hat sath cit ay AE a= 2 Pour ; ef of tea OW TRY M \ emma. Stele aN Z Bee \ ‘ x EA. eat ae Ne 4 Ax oy Bek ‘ = es . saparoties aU oo i) . : , " Ps SL * peg ~ CONTENTS (continued). List of Presents On the Method of Condensation in Calorimetry. By J. Joy, B.E., Assistant to the Professor of Civil Engineering, Trinity College, Dublin (Plates 6 SHEL 7) oe GR IRE Mseat SR es Ss of eee Obituary Notices :— JAMES APJOHN . E WILLIAM BENJAMIN CARPENTER PUBLISHED BY HER MAJESTY’s STATIONERY OFFICE, 4 CATALOGUE OF SCIENTIFIC PAPERS, Compiled by the Royal Society. Vols. 1 to 8. Price, each volume, half morocco, 28s., cloth, 20s. A reduction of one-third on a single copy to Fellows of the Royal Society. Sold by Eyre and Spottiswoode. Price 20s. CATALOGUE OF THE SCIENTIFIC BOOKS IN THE LIBRARY OF THE ROYAL SOCIETY. First Section :—Containing Transactions, Journals, Observations and Reports, Surveys, Museums. SEconpD SecTIoN :—General Science. A Reduction of Price to Fellows of the Society. HARRISON AND SONS, 45 & 46, ST. MARTIN’S LANE, W.C., AND ALL BOOKSELLERS. Be SS THE ROYAL SOCIETY. VOL, XLI. | : No. 249. L¢ 3 ‘ % Bees 7 Oe “an f Noite pea) ee ] 1% f y an 7 5 fa ; CONTENTS,- (0 ee November 30, 1886. = ee, ANNIVERSARY MERTING. REPEC PAUNCLILOSS ia ay a ah A ee a o i List of Peticw: deceased since last Anniversary : : 4 é ; . 3872 ; elecied unis : ala ae ; Be Mee any Ok _ Address of the President. : i : ; : d aang A . 373 j : Blection of Counciland Officers .. : : d ee : \ . 886 Table showing Progress end present State of Society with regard to Fellows . 386 Financial Statement . ; , 5 : ‘ ; ‘ i . 3887—390 “ Trust Funds . 3 : } 4 ‘ Arie t : 3 : . S91 SOR as Account of the appropriation of the sum of £4,000 (the Government Grant) annually voted by Parliament to the Royal Society, to be employed in ei aiding the Advancement of Science ; : : a ae : se BOG ie ih Account of Grants from the Donation Fund . : : ; ‘ : | 399; cs Report of the Kew Committee ; : : eee ; , : . 400 The Minute Anatomy of the Brachial Plexus. By W. P. HEerRineuam, i M.B., M,R.C.P, : ; : : : : : : ; . . 423 Price Two Shillings. PHILOSOPHICAL TRANSACTIONS, Part I, 1886, CONTENTS, I. A Memoir on the Theory of Mathematical Form. By A. B. Kemps, M.A., F.R.S. II. On Evaporation and Dissociation.—Part I. By Professor WILLIAM RAMSAY, Ph.D., and Sypnry Youne, D.Sc. III. On Evaporation and Dissociation.—Part iE eA Study of the Thermal Properties of Alcohol. By Witilsam Ramsay, Ph.D., and SypNEY YouneG, D.Sc. IV. On the Theory of Lubrication and its Application to Mr. Beauchamp Tower’s Experiments, including an Experimental Determination of the Viscosity of Olive Oil. By Professor OsBsorNE REeynoubs, LL.D., F.BRS. VY. Further Observations on Enterochlorophyll and Allied Pigments. By C. A. MacMunn, M.A., M.D. VI. Researches on Myohematin and the Histohematins. By C. A. MacMuny, M.A., M.D. VII. An Experimental Investigation into the Form of the Wave-Surface of Quartz. By James C. McConnet, B.A. VIII. Description of Fossil Remains, including Foot-Bones, of Megalania prisca.—- Part IV. By Sir RicHarp Owen, K.C.B., F.R.S., Ke. TX. Dynamo-Hlectric Machinery. By J. Hopkinson, M.A., D.Sc., F.R.S., and BK. Hopxinson, M.A., D.Se. Index to Part I. Price £1 8s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, may be had of Triibner and Co., 57, Ludgate Hill. . | | ] | | | ee ot ee oe ees ee SS + ~ On the Method of Condensation in Calorimetry. 371 Complete Formula for Calculating the Specific Heat. Collecting the foregoing corrections we get a formula for use if very considerable accuracy be desirable, but it is to be observed that under any ordinary circumstances correction (1) on w, of —V x ‘000063 is sufficient. The complete formula for S, the specific heat, is— g— 1:000589[w, —V x 0000636][536-5 +0°7(100—4°)] WG-4) ; the several weights observed being supposed reduced to vacuo as usual, otherwise the letters being as before. VOL. XL. 2 ¢ Anniversary Meeting. November 30, 1886. ANNIVERSARY MEETING. Professor STOKES, D.C.L., President, in the Chair. The Report of the Auditors of the Treasurer’s Accounts on the part of the Society was presented, by which it appears that the total receipts during the past year, including balances carried from the preceding year, amount to £7,226 8s. 9d., on the General Account, and £10,107 7s. 1d. on account of Trust Funds, and that the total. expenditure in the same period, including purchase of stock, amounts to £5,363 12s. 114d., on the General Account, and £6,911 16s. 6d., on account of Trust Funds, leaving a balance on the General Account of £1,838 5s. 10d. at the Bankers’, and £24 9s. 1l4d. in the kands of the Treasurer, and on account of Trust Funds a balance at the Bankers’ of £3,195 10s. 7d. The thanks of the Society were voted to the Treasurer and Auditors. The Secretary then read the following Lists :— Fellows deceased since the last Anniversary (Nov. 30, 1885). On the Home List. Apjohn, James, M.D. Boileau, John Theophilus, Major- General, R.H., F.R.A.S. Bunbury, Sir Charles James Fox, Bart. BAG:S:. Busk, George, F.L.S. Cardwell, Edward, F.G.S. Chapman, Thomas, F.8.A. Cobbold, T. Spencer, M.D. Euniskillen, William Willoughby, Earl of, D.C.L. Evans, Sir Frederick J. Owen, 120d.” BN. Viscount, Fergusson, James, C.I.H., D.C.L. Forster, Right Hon. William Edward. Guthrie, Professor Frederick. Shadwell, Sir Charles Frederick Alexander, Vice - Admiral, K.C;B: Solly, Edward, F.S.A. Strafford, George Stevens Byng, Earl of. Thomas, Edward, C.I.E., ¥.S.A. Waveney, Robert Alexander Shafto Adair, Lord. Withdrawn. Bouverie, Right Hon. Edward Pleydell. 1886. ] . President's Address, | BB) Fellows elected since the last Anniversary. Bidwell, Shelford, M.A. Russell, Henry Chamberlaine,. Colenso, William, F.L.S. B.A. Dixon, Harold B., F.C.S. Sedgwick, Adam, M.A. Festing, Edward Robert, Major- | Thurlow, Right Hon. Thomas General, R.E. John Hovell--Thurlow Cum- Forsyth, Andrew Russell, M.A. ming-Bruce, Lord. Green, Professor A. H., M.A. Unwin, Professor W. Cawthorne, Horsley, Prof. Victor, F.R.C.S. B.Se.. Meldola, Raphael, F.R.A.S8. Warington, Robert, F.C.S8. Pye-Smith, Philip H., M.D. Wharton, William James Lloyd, Rosebery, Right Hon. Archibald Captain R.N. Philip Primrose, Earl of. Wilde, Henry. On the Foreign List. Baeyer, Adolf. Kowalewski, A. Klein, Felix. Lovén, Sven.. The President then addressed the Society as follows :— For many years it has been my duty as senior Secretary to read at each Anniversary the death-roll of the year. The names this year are perhaps slightly fewer than usual, but many recall to us faces once familiar that we shall never see here again. LHarliest among them comes Sir Frederick Hvans, whose death took place only very shortly after our last Anniversary. In the course of the preceding summer he crossed the Atlantic to take part in that International Conference which assezbled at Washington, to deliberate among other things on the choice of a common: prime meridian for all civilised nations. On his return he was looking ill, and the illness increased until it carried him away. Yet even through his illness he kept on working at science, at a task he had undertaken, and which was almost completed when he died. To this I shall have occasion to refer again. In Mr. Busk we have lost one whose detailed know- ledge of certain branches of natural history and comparative anatomy was almost unrivalled. He took an active part in the scientific business of the Society, and repeatedly served on our Council, and both then and subsequently gave us the benefit of his extensive knowledge and sound judgment in the important but laborious task of reporting on papers. In Lord Cardwell we have lost a statesman whose political duties did not prevent him from coming among us and serving on our Council. The public services and singular honesty and straightforwardness of Mr. Forster are appre- ciated by the nation at large. Quite recently, at no advanced age, 202 374 Anniversary Meeting. [Novy. 30, we have lost Professor Guthrie, the occupant of a chair which a great many years ago I held for a time; a man whose genial character drew around him a close circle of friends. Still more recently we have lost the Harl of Enniskillen, whose fine paleontological collec- tions are well known to geologists. Only the other day one passed away whom we seldom missed at our anniversary meeting, and who was frequently with us on other occasions: I allude to General Boileau, whose philanthropic labours will not soon be forgotten, and may, I trust, be recognised in a much needed form. The Fellows will have noticed with satisfaction a very considerable excess of income over expenditure in the balance sheet for the year. At first sight it might be supposed that as the ‘Transactions’ come out at irregular intervals there might have been fewer parts published than usual; but it will be found on examination that the past year has borne its proper share of printing expenses. The excess is really due to a substantial improvement in the Society’s property, under the careful and judicious management of our Treasurer. Last. year our President informed the Fellows of the munificent offer made to the Society by Sir William Armstrong to give to the Scientific Relief Fund the sum of 6,5001., provided an equal sum were raised within a year by subscription from the Fellows, and if need be, other friends of science who might not belong to the Society. As the Fellows are aware, a circular was sent round by the Treasurer men- tioning Sir William Armstrong’s generous offer, and inviting sub- scriptions ; and the Treasurer has also written privately to a number of persons, Vellows, and others. The sum subscribed or promised in response to this invitation amounts to about 4,200/.; and though the sum thus raised does not amount to what Sir William promised to duplicate if it could be raised, he has most generously not only waived the non-fulfilment of the condition subject to which the former offer was made, but has still further augmented it; and he now promises not only to duplicate the sum raised in answer to the Treasurer’s appeal, but to give the further sum of 3,600/., thus raising the capital from the present sum of about 8,000/. to 20,0001. He will be ready to pay the whole sum of 7,800/. as soon as the sub- scriptions promised to the Treasurer have been collected. The only condition attached to this princely gift is, that besides meeting the ordinary objects for which the Fund was instituted, the Council should feel themselves at liberty to apply a portion of the income towards the remission of fees in cases of urgent necessity. The path of the total eclipse of the 9th of September last year, in any place where it fell on land, was so remote from this country that no expedition went out to observe it. It was visible in New Zealand, and in anticipation of it our Eclipse Committee sent out a memo- randum to the Colony indicating the points of special interest to look 1886.] President's Address. Br) out for. We have received accounts, drawings, and photographs of the eclipse from Dr. Hector and others. One of the most remarkable features of this particular eclipse was the appearance of two white and unusually bright prominences which attracted general notice, and were compared to electric lamps, and which, situated on opposite sides of the sun, were just over the places of two large spots, one close to the limb, and on the point of disappearing, the other not seen before the eclipse but visible next day, having in the meantime come round the limb. The present year afforded another of those rather rare occasions, always of brief duration, which are afforded for the study of solar physics by a total eclipse of the sun. Calculations made long before- hand showed that a total eclipse was to be expected on the 29th of August. The path of the total phase on the earth’s surface is always narrow, say 100 miles or so across, and on this occasion it swept obliquely across the Atlantic Ocean, cutting the Western Coast of Africa about Benguela, and sweeping across some of the West India Islands to a part of the mainland of South America, where it ended. Though there was a long belt of ocean over which the totality would be visible, and where the imposing spectacle of a total eclipse might be witnessed, this was not available for regular scientific obser- vations, which require Jand on which to fix the instruments. On the mainland of America the total phase would come on so shortly after sunrise that the sun would be too low for good observations, and therefore the Island of Grenada, which lay within the belt of totality, was much to be preferred. Of the two available stations, one lay in the British dominions, and was pretty easy of access from England, and accordingly it seemed to be the duty of our country to take a foremost place in the observations, the results of which would be available to the whole scientific world. It was contemplated first to send expeditions to both places—to Benguela as well as Grenada. The cost of this would, however, exceed what could be spared from the Government Grant without unduly curtailing what was available for other objects. Ac- cordingly application was made to the Lords of the Treasury for a grant of 1,000/. towards the cost of the expeditions. Enquiries were also made as to the probable climate at the two places; and here I have to express our thanks to the Governor-General of the Windward Islands, who put us in communication with Dr. Wells of Grenada, from whom we obtained valuable information regarding the climate of that island, and to the Consul-General for Portugal, who obtained information for us from the Polytechnic Institution at Lisbon as to the amount of sunshine about the end of August at Loanda, which may be taken pretty well as representing Benguela. _ The information we obtained from various sources as to Benguela 376 Anniversary Meeting. [Nov. 30, was rather conflicting, but there seemed a pretty general agreement that even if the sun should be shining at the time of the eclipse the sky was likely to be hazy. This would much interfere with good observations, especially as regards the corona; and as the expense of the expedition to Benguela would be considerable, and the success very doubtful, we thought it better to give up that part of the project and confine ourselves to Grenada. Being anxious to trench as little as possible on the national expenditure, and finding that a little more could be taken from the Government Grant than we had expected, we wrote to the Treasury reducing our application to 500/., which with assistance from the Admiralty in the shape of the use of a ship-of- war on the West Indian station, and supplemented by some money from the Government Grant and from our own Donation Fund, might enable us to meet the expenditure. The result was that a sum not exceeding 5001., to supplement what could be spared from the Government Grant, was granted, and the expedition, as the Fellows are aware, has sailed and returned. It was fairly successful, the observations having been prevented by clouds at only one of the stations occupied. There has not yet been time to discuss the observations in, full, but two points already appear to have come out pretty clearly. One is that the brightness of the corona, which on this occasion was actually measured, was much less than had been expected, and less apparently than it had been on former occasions. This seems to show that the brightness is liable to great changes when we compare different years, as we know is the case with the form. The other point touches on the question of the possibility of photographing the corona inde- pendently of an eclipse. If the photographic brightness of the corona be not overpowered by that of the atmospheric glare immediately around the sun when there is no eclipse, then when the sun is partially eclipsed we might expect to be able to trace the outline of the limb of the moon for some way outside the sun, since the moon would be projected on the background of the corona. The experi- ment was tried both by Captain Darwin at Grenada, and by Dr. Gill at the Cape, but in neither case was the limb traceable outside the sun. This throws doubt on, but does not disprove, the validity of the method proposed by Dr. Huggins; for he himself has never obtained photographic appearances apparently referable to the corona since the Krakatoa eruption. It may be that the finely suspended par- ticles, whether connected with the Krakatoa eruption or not, which produced those gorgeous sunsets that were so remarkable, have not yet wholly subsided, and cause a considerably increased atmospheric glare. It may be that the corona has actually been much less ese than usual for the last few years. The present year has been signalised by that remarkable volcanic 1886.] President's Address. atT explosion in New Zealand, of which we have read accounts in the newspapers. We have received from Dr. Hector a series of photo- graphs of the district, taken at no great length of time after the explosion. The Krakatoa Committee, which was appointed at the suggestion of our late President to collect information relative to the great eruption, have now I may say completed their work. The Royal Meteorological Society had appointed a Committee to get together information respecting the remarkable atmospheric phenomena witnessed after the eruption. It was thought desirable that the two Committees should work in concert, and accordingly our Committee was enlarged by the addition of two members of the Royal Meteorological Society, even though they did not happen to be members of the Royal Society, who undertook that share of the work, ‘The information collected under this head is naturally volu- minous, since it requires no special training to describe the atmo- spheric appearances. Our late Fellow Sir Frederick Hvans undertook the sea disturbance, and continued to. work at it even in an advanced stage of the disease which carried him off. -Another fortnight, it was estimated, would have enabled him to complete it. His account was found to have been written in pencil on separate sheets of note paper, but his successor in the office of hydrographer, Captain Wharton, our Fellow, was so good as to take up the work; and partly by the use of materials left by Sir F. Evans, partly by his own independent labour, he has now completed it. The report on air disturbance was undertaken by General Strachey, and is ready. Professor Judd undertook the geological part; the materials are ready, and though the actual report is not yet written, the writing would take but very little time. Mr. Scott undertook to collect information as to floating pumice; but as it has been found that the Krakatoa pumice does not possess distinctive features whereby it could be recognised, and therefore the origin of the pumice that ships have encountered at a distance from Krakatoa remains unknown, little trustworthy infor- mation could be obtained under this head, and the report has been handed over to Professor Judd to embody with the geology. The heaviest part of the report, that relating to sunsets and atmespherie phenomena, has been prepared by the Hon. Rollo Russell and Pro- fessor Archibald, the two Fellows of the Royal Meteorological Society who have been mentioned as having been added to the Committee, and is ready, with the exception of a little revision, and it remains only to prepare an introduction, index, &c. The whole report may therefore be regarded as all but complete in manuscript, and it will be for the new Council to deal with it. _ The Circumpolar Committee have now brought their labours to a close, the report on the observations taken by Captain Dawson a6) Anniversary Meeting. — [Nov. 80, at Fort Rae being printed and published. The reports of the expeditions undertaken by Austria, Germany, and the United States © of America, are, I believe, complete, and those by France, Holland, and Russia are in a forward state. Before the accounts of the obser- vations taken at different stations by the observers of different nations shall have been for some time before the public, it would be premature to expect general conclusions to be deduced from this great undertaking. Very satisfactory progress has been made during the past year with the publication of the Report of the “‘ Challenger ” Hxpedition. Tbe volumes already published and in the Society’s Library now amount to sixteen on Goology, and three introductory on other sub- jects. Others are in a very forward state, and it is expected that the whole will be published very nearly within the time mentioned by the Committee, probably by the end of the next financial year. As mentioned in the Presidential Address last year, advantage has been taken of the British occupation of Hgypt to make some explora- tions by way of boring in the Delta of the Nile, to the results of which geologists attach great importance. The War Department has allowed some of the staff of the Royal Engineers, when their services were not otherwise required, to take part in the operations, and has lent the boring apparatus, and the Royal Society voted the sum of 3501. out of its own Donation Fund to defray the cost of Jabour and other incidental expenses. It was contemplated originally to make a chain of borings, but the depth to which it has been found necessary to proceed in order to get through the ordinary deposit has turned out to be so great that it was thought better, instead of attempting many, to try and get if possible down to rock, or to something else which might afford evidence that what could be referred to alluvium from the Nile or drifted sand had really been got through. A deep ‘boring has accordingly been made at Zagazig, under the direction of Captain Dickenson, R.E. This has now been carried to a depth of 190 feet 6 inches below the surface, or 164 feet 5 inches below the mean sea-level at Alexandria, and yet nothing has been reached but sand and clay with small pebbles. Professor Judd is now engaged in the examination of the matter brought up. A derangement of the boring apparatus prevented for the present further progress, and the use of a narrower pipe than any at hand would be required for carrying the boring deeper. The Committee considered that it would be more important to extend this. boring, so as if possible to get down to rock, or else to some deposit with fossils, than to make a fresh boring in a different place, and arrangements are being made accordingly. The inquiry was deemed a proper one to be assisted out of the Govern- ment Grant, and the sum of 200/. bas been voted from this source to supplement the Royal Society’s grant already mentioned. 1886. | 7 President's Address. 379 The ordinary meetings of the Society are well known, and are frequently attended by strangers by permission of the Fellows present; and the papers brought before us are known to the world through our publications. But a great deal of scientific work is done of which the outside public know nothing. There have been thirteen meetings of the Council during the year, and the attendance at our Council meetings is remarkably good. There have been more than seventy meetings of Committees and Sub-Committees. There is further another task on which a great deal of gratuitous and consci- entious labour of the highest kind is bestowed, I allude to the examination of papers with a view to advising the Committee of Papers as to their publication. The past year has shown no flagging in scientific activity, in relation to papers brought before us. Since the last Anniversary three parts of the ‘ Philosophical Transactions,’ comprising upwards of 1160 pages of letterpress and 95 plates, and eight numbers of the ‘ Proceedings,’ containing 1299 pages, have been published. The preparation of the manuscript for another decade, 1874 to, 1885, of the Royal Society’s catalogue of scientific papers, is now almost complete. This great work has been extremely useful to men of science in enabling them at once to find where a memoir on a par- ticular subject, written by an author whose name they know, as is usually the case, is to be found. To some extent it enables them also to find what has been written on a particular subject, for there are usually one or two authors, whose names they know, who have made it a special study, and on consulting their papers references are frequently found to the writings of others who have written on the same subject. Nevertheless it must be confessed that the value of the catalogue would be greatly increased if it could be accompanied by a key, of the nature of an index rerum. It was originally contemplated that this should be added, but the magnitude of the undertaking has hitherto prevented the Committee from attempting it. To be well done it would require the long-continued labour of a scientific staff representing different branches of science, and they could not be ex- pected to engage in so heavy a work without adequate remuneration. A great deal of work has been done during the past year in relation to the Library. More than 5,000 volumes have been removed to other rooms to make space for the more important works constantly accruing. A list of duplicates and deficiencies has been printed, and circulated among corresponding Societies. A shelf-catalogue is in progress, and is about a third of the way towards completion. Some work has also been done upon a catalogue of miscellaneous literature. The electric lighting of the Society’s apartments, which is now complete, seems to have given general satisfaction. On the 31st of August this year, our distinguished Foreign Member, 380 Anniversary Meeting. [Noy. 30, M. Chevreul, attained his hundredth year. Rarely indeed is it given to anyone to see right through a century, more rarely still to retain his powers to such an age, yet both, I am happy to say, have been granted to M. Chevreul. In anticipation of this event, preparations were made for its due celebration. I received an invitation for our Fellows to assist at the celebration; but unfortunately it was ata time of year when most of us were scattered, and moreover time did not permit of making it generally known. I am afraid we had no representative at the actual ceremonial, but I am sure that none the less our hearts were with the veteran savant. This year has also witnessed the celebration of the 250th anni- versary of the University of Heidelberg. The Council had appointed our Foreign Secretary as a deputation to represent the Society on the occasion. Unfortunately when the time was close at hand, Dr. Wilhamson was prevented by the condition of his health from taking part in the celebration; but acting on the emergency on behalf of the Society, I requested our Fellow, Sir Henry Roscoe, to take his place, which he was so good as to do. In his Presidential Address last year Professor Huxley suggested the idea, I may say expressed the hope, that the Royal Society might associate itself 1n some special way with all English-speaking men of science; that it might recognise their work in other ways than those afforded by the rare opportunities of election to our foreign member- ship, or the award of those medals whieh are open to persons of all nationalities alike. This suggestion has been taken up in one of our Colonies. We have received a letter from the Royal Society of Vic- toria, referring to this passage in the Address, and expressing a hope that in some way means might be found for establishing some kind of connexion between our own oldest scientific Society and those of the Colonies. The Couneil have appointed a Committee to take this letter into consideration, and try if they could devise some suitable plan for carrying out the object sought. The Committee endeavoured at first to frame a scheme which should not be confined to the Colonies and Dependencies of the British Empire, but should embrace all English- speaking communities. But closely connected as we are with the United States by blood and language, they are of course politically a foreign nation, and this fact threw difficulties in the way of framing at once a more extended scheme, so that the Committee confined themselves to the Colonies and Dependencies of our own country, leaving the wider object for some future endeavour, should the country concerned seem to desire it. The scheme suggested was laid before the members of the present Council, but there was not an adequate opportunity of discussing it, and it will of course come: before the new Council. Should they approve of some such measures 1886. | President's Address. 381 as those recommended by the Committee, they will doubtless assure themselves in some way or other that those measures are in accord- ance with the wishes of the Fellows at larye before they are incor- porated into the Statutes. But in connexion with this subject there is another suggestion which I would venture to offer, and which I know has been thought of by others. A good many years ago it was not unusual to elect to the Fellow- ship men of distinguished eminence in departments other than scientific. More recently a change was made in the Statutes whereby Privy Councillors are enabled to become Fellows by a special method, without interfering with the selection by the Council of fifteen from among the candidates, whom they recommend to the Society for election. This to a certain extent superseded the necessity of appealing to other than scientific claims, and in some respects the method had special advantages. Those who attained to a place on Her Majesty’s Privy Council were sure to be distinguished men, whom we should be glad to welcome among us; and by confining the privilege of special election to these, with whose appointment the Council had nothing to do, all invidious distinctions were prevented. But the method has the disadvantage that it applies only to a particular class of merit. A man, for instance, might be of quite first rate eminence in poetry or literature, but that would not lead toa seat on the Privy Council. Such a man could only be elected by being placed on the selected list of fifteen. But it seems to me that there is something not quite courteous either to the eminent man himself, er to the scientific man who would have to be passed over to make room for him, in thus putting him in competition with those who seek admission on purely scientific grounds. I cannot help thinking that it might be well if the Council had the power of recommending for special election men of high distinction on other than scientific grounds, whose connexion with us would on both sides be felt to be an honour, and who, though not it may be themselves scientific, might usefully assist us by their counsel. I do not think 1t would be difficult to devise means for providing that such a privilege should be accorded only in case of very high eminence. The application of photography to the delineation of celestial objects has of late years made rapid strides ; and, partly owing to the improved sensitiveness of the plates, partly to greater exactness in regulating the motions of equatorially mounted telescopes, it has been found possible to photograph even minute stars. ‘The question is accordingly now seriously entertained whether we may not trust to photography for the formation of star maps and star catalogues, taking eye observations on a sufficient number of stars here and there for reference, and trusting to differential measurements taken on the 382 Anniversary Meeting. [Nov. 30, plates for determining the positions of the other stars. Indeed I think the practicability of this application may now be considered as esta- blished, and there only remains the question of the best mode of carrying it out on a uniform plan. In the course of the autumn I had a letter from Admiral Mouchez, Director of the Paris Observatory, in which he informed me that in response to the presentation of specimens of the admirable star photographs taken by the MM. Henry, several of the astronomers to whom they had been sent suggested that it would be well that a conference of astronomers of various nations should be held, with a view to taking concerted action for obtaining on a uniform plan a complete map of the whole starry heavens. He wished accordingly to obtain an expression of opinion on the part of the Royal Society as to the desirableness of holding such a conference ; and as it was contemplated, in case the proposal should be favourably entertained by those consulted, that the con- ference should be held at Paris in the spring, and it would be neces- sary to give timely notice to the astronomers who live in the southern hemisphere, an early reply was requested. As it would have defeated Admiral Mouchez’s object to wait till the Council should reassemble after the recess, I wrote at once to consult four of our Fellows specially named by Admiral Mouchez ; and on receiving their replies I wrote to Admiral Mouchez, saying that under the circumstances I took it upon me to express in the name of the Royal Society our approval of the suggestion, explaining at the same time that I did so on the understanding, which I fully believed to be in accordance with his intention, that the astronomers who might attend the conference should not be considered as pledged to the adoption of the methods or scaie of the MM. Henry, but that the whole subject should be open to discussion. On reporting what I had done to the Council when they met after the recess, I obtained an expression of their approval. In these photographs a remarkable instance was exhibited of the power of photography to reveal the existence of objects wholly invi- sible to the eye. One of the stars of the Pleiades was found to be surrounded by a nebula which cannot be seen with telescopes. The reason of the difference of power of the plate and eye is very obvious ; with the eye an object is either seen or not seen at once, whereas with the plate, provided there be an absence of stray light, feebleness of intensity can be made up for by length of exposure. But the MM. Henry are by no means the only persons who have applied photography to the delineation of the stars. Among others our Fellow, Dr. Gill, who has sent us some excellent specimens of the photographs obtained by his instrument, proposes to take at the Cape Observatory photographs of the whole starry heavens of the southern hemisphere, under such conditions as to include the magnitudes 1886. | President's Address. 383 contained in Argelander’s “ Durchmusterung” of the northern hemisphere, and to subsequently reduce the observations so as to complete Argelander’s great work by extending it to the southern hemisphere. Professor Kapteyn, in Holland, has nobly undertaken to devote his spare time for seven years to superintending the reduc- tion. Dr. Gill has laid the proposal before the Government Grant Committee.- Having regard to the magnitude of the undertaking, and the probability of a conference of astronomers being shortly held in Paris to discuss the whole question, the Government Grant Committee suggested to the Council of the Royal Society that they should appoint a committee to take the subject into consideration, and the Council have acted on this suggestion. Dr. Gill imtends to come to Hurope in the spring, so that the committee will be able to consult him personally. This morning I received through the Foreign Office an invitation from the Académie des Sciences for myself, or some other Delegate of the Royal Society, to attend the conference to which I have already referred, which is fixed for the 16th of April. I shall take the first opportunity of consulting the new Council as to their wishes. The Copley Medal for this year has been awarded to the veteran in science, our foreign member, Professor Franz Hrnst Neumann, for his researches in theoretical optics and electro-dynamics. Having in his earlier years treated of crystallographic subjects, he more than half-a-century ago turned his attention to the theory of light. Fresnel had, with his wonderful sagacity, arrived at his celebrated laws of double refraction from the theory of transverse vibrations, aided by conceptions derived from a dynamical theory which was only in part rigorous. Cauchy and Neumann, indepen- dently of each other, were the first to deduce from a rigorous dynamical calculation, applied to a particular hypothesis as to the constitution of the ether, laws of double refraction, not indeed absolutely identical with those of Fresnel, but closely resembling them. In this case the laws were known beforehand. But ina very elaborate later paper, Professor Neumann deduced from theory the laws of crystalline reflection, laws which appear to agree with the observa- tions of Seebeck, and which had not been discovered by Fresnel, though some of them were independently and about simultaneously obtained by MacCullagh. Professor Neumann is perhaps still better known in connexion with the theory of electrodynamics, and the mathematical deduction of the laws of induced currents due to the motion of the primary and secondary conductor. He may be said to have completed for the induction of currents the mathematical treatment which Ampére had applied to their mechanical action. Of the two Royal Medals, it is the usual, though not invariable, 384 Anniversary Meeting. [Nov. 30, practice to award one for the mathematical and physical, and the other for the biological sciences. One of these medals has this year been awarded to Professor Peter Guthrie Tait, for his various mathematical and physical researches. Professor Tait is well known for his numerous and important papers in both pure mathematics and physics. The late Sir William Hamilton regarded him as his own successor in carrying on and completing the newly invented calculus of quaternions, of which Professor Tait is continually making new applications. Among his investigations in the domain of experimental physics may be men. tioned his determination of the conducting powers of metals for heat by a method which appears to possess special advantages, and his investigation of the effect of extremely great pressures on ther- mometers, undertaken with a view to deducing correct results for the temperatures at great depths in the ocean from the observations made in the “ Challenger” expedition. This latter subject has led him to investigate the behaviour, as to compressibility and develop- ment of heat, of liquids and solids under enormous pressures, a subject in which he is still engaged. Before concluding I must mention his elaborate papers on systems of knots, recently printed in the Transactions of the Royal Society of Edinburgh. The other Royal Medal has been awarded to our Fellow, Mr. Francis Galton, for his statistical inquiries into biological phenomena. Mr. Galton is well known as an explorer and geographer, and his mind is singularly fertile in the devising of ingenious instruments for various objects. Many years ago he brought before us some remarkable experiments instituted with a view to test a particular biological theory, in which rabbits of a pure variety were so con- nected with others of a different variety that the same blood cir- culated through both individuals, and the point to determine was whether this blood-relationship, in the most literal sense of the term, had any effect on the offspring. Contrary to what the theory in question led us to regard as the more probable, the result proved to be negative. It is, however, in accordance with the rules for the award of the Royal Medals, more especially the later investigations of Mr. Galton, in relation to vital statistics, that have been taken as the ground of the award. He has shown that by taking the average of a number of individuals having some condition in common, indivi- dual peculiarities apart from that condition are eliminated in the mean, and results are obtamed which may be regarded as typical of that condition. One way of doing this is by his method of compound photographs. Thus we may obtain typical features of criminals of a particular kind, of consumptive persons, and so forth. By adhering to the method of averages, he has even succeeded in obtaining a mathematical expression, very closely verified by observation, con- 1886. | President's Addvess. 385 necting the mean deviation of some condition (such for example as stature) in a series of individuals from the general average with the mean deviations of the same condition in the relatives of those same individuals of different kinds, such as fathers, brothers, &c. Nor is the statistical method applicable to bodily characteristics alone. Mr. Galton has even extended it with remarkable ingenuity and originality to mental phenomena also. The Rumford Medai has been awarded to Professor Samuel P. Langley, for his researches on the spectrum by means of the bolo- meter. A better knowledge of the ultra-red region of the spectrum, which > includes the larger part of the energy of solar radiation, had long been a desideratum, when Professor Langley commenced his work upon this subject. Finding the thermopile insufficiently sensitive for his purpose, he contrived the ‘“‘ bolometer.”” This instrument depends upon the effect of temperature upon the electrical resistance of metals, a quantity susceptible of very accurate measurement; aud, with its aid, Professor Langley has been able to explore a part of the spectrum previously almost inaccessible to observation. A result of Professor Langley’s work, very important from the point of view of optical theory and of the ultimate constitution of matter, relates to the law of dispersion, or the dependence of refran- eibility on wave-length. Cauchy’s formula, which corresponds well with observation over most of the visible spectrum, is found to break down entirely when applied to the extreme ultra-red. Professor Langley has given much attention to the important ques- tion of the influence of the atmosphere on solar radiation. The expedition to Mount Whitney, successfully conducted by him in face of many difficulties, has given results of the utmost value, pointing to conclusions of great interest and novelty. The Davy Medal has been awarded to our foreign member, M. Jean Charles Galissard de Marignac, for his researches on atomic weights. M. Marignac’s numerous researches on atomic weights, which have been continued for a great number of years, have played an exceed- ingly important part in establishing and consolidating that ground- work of chemistry. They are remarkable for originality in devising methods appropriate to the respective cases, the most conscientious care in discovering errors which occurred in the respective operations, and indefatigable perseverance in finding means to eliminate the disturbing influences. His labours are all the more valuable because he chose for their field chiefly those elements which are most generally used in chemistry, and are most important to chemists, and on which the determination of new atomic weights is most generally made to depend. 386 Anniversary Meeting. [Nov. 30, The Statutes relating to the election of Council and Officers were then read, and Sir Hrasmus Ommaney and Mr. Stainton having been, with the consent of the Society, nominated Scrutators, the votes of the Fellows present were taken, and the following were declared duly elected as Council and Officers for the ensuing year :— President.—Professor George Gabriel Stokes, M.A., D.C.L., LL.D. Treasurer.—John Evans, D.C.L., LL.D. Professor Michael Foster, M.A., M.D. Secretaries.— : The Lord Rayleigh, M.A., D.C.L. Foreign Secretary.—Professor Alexander William Williamson, LL.D. Other Members of the Council. Professor Robert B. Chfton, M.A.; Professor George Howard Darwin, M.A., LL.D.; W.'T. Thiselton Dyer, M.A.; Professor David Ferrier, M.A.; Edward Frankland, D.C.L.; Arthur Gamgee, M.D.; Archibald Geikie, LL.D.; Professor Joseph Henry Gilbert, M.A.; John Hopkinson, M.A., D.Sc.; J. Norman Lockyer, F.R.A.S.; Sir Lyon Playfair, K.C.B., LL.D.; Professor Bartholomew Price, M.A.; Professor Pritchard, M.A.; Admiral Sir George Henry Richards, K.C.B.; Professor Arthur Schuster, Ph.D.; Philip Lutley Sclater, M.A. The thanks of the Society were given to the Scrutators. The following Table shows the progress and present state of the Society with respect to the number of Fellows :— Patron ; = Com- £4 £3 fowl Foreign. pounders. yearly. | yearly. Total. Nov. 30, 1885 .. 5 45 196 182 Since Elected .. + 4 a pet f= ee a Since Withdrawn = | | Since Deceased .. — | tony Nov. 30, 1886 .. 5 49 192 172 iS 6 8 92C°LF 6 8 Y2OLF oD OT G QagiT cette teens ne sromTeg ge aun ap 0 Il Cece cnrreevevrererercecenverscecs Use 4449.7 ‘OIL 66 TIL 6 ue 6 é1 qunodDV onsorezeg ‘ ‘otee uo soured ‘ az Oot Z 84 ee a (onp ‘pT ‘se [ETF soouvape snotaoad N QTL suryeur) peoneanE yseg Or ped xo asdrpoa oe OL 61 1g Coeerereesreoecenee eeccorsces CORPO CODPi coeerereccsseoseoers sodIVI MOT (79 6 aT 0g DOCOCOOOODCOOOOUOCIO C4 sate SnooURTOOST I, (a3 g IL 6 Oe eeoererereeseovercvererers Cee reeeeeecee een sonrvyO A449. pue ‘soo ‘(saepnorty JPY OfQUSTOG Surpnpoul) osxqysog “ a 0 6T ST SUDDOBUOUOOUDCUOOCOUCOCOOOUCDOOO NOOO Ob0000 , SUISTIIOAPW (13 = 0 P 99¢ g cl 19 Welvisisielin stele GOGUOOOS SO QAOOCDOOE SO RATIOOCUDDO COE HOCOO SOxe : OL P 0Z Cevervcesccdevecveccccsserecceee ““-ATIN000V SYST[BAN gw NT yo souReg ce S 0 Cl reye eovcveee Cevcrecccccscccocece ecccecce SoOUBINSUT orl é G 9 SIZ T Core vcecvccsccccoccvesce ssuTpo0001 pur SUOTJOVSUBLT, jo oyeg ¢é Ss STI OT 0% Oo eecesevee teccceees Cer eeeercerconsenoes sosuod xn eoT, (73 0 0 O8¢ Oeveeeeeccvccer Cecececcccecccccceccece eecees Uvory 9SVSLOT TO qso1oquy “ 8 Sy z CZI Per eeeceverecces Cer vccccccecccvecece sostod xq osnoyy (79 OT Cc) OST oer Coc cccccecrcesvceee Coecevere Coe ecereveeenses puny [[otpor ‘op a) 40 OL Gg Pe eecrrcecvecccceeee Cevecscoecccccce Basmoultch sue) cc g y, Cees Coveccccvcce Coccescccce . 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Coast of Ireland .............6 se 100 Dr. W. R. Dunstan, for investigation of the physiological Properties of the glucoside Loganin which occurs in Strychnos NU VOWUUCE aac ws ic toe wiete's oleh 6. © ow lenis oeloce | Sie 75 Dr. F. R. Japp, for an investigation of the reactions of Ketones, Diketones, and allied compounds .......... » econ 75 Prof. Humpidge, for apparatus to continue a Research on the Specific Heats of the Solid Elements in the pure state and ab varying benrperabures 2. 1s. sc. eso elem oe isle 50 Prof. Humpidge, for his Research on Metallic Glucinum.... 12 W. EH. Adeney, for completion of the work of determining the Wave-lengths and Mapping the Lines of the Ultra-vielet Spark-spectra of Nickel, Cobalt, Palladium, Gold, and PRAGA 6s oss oem pie lhe eo inls seek eietie)s fees «a 50 The Scottish Meteorological Society, for an investigation on Sea-temperature, and a discussion of observations from 1855 to present time ......0+ ETE sey EN ele are Were sc 50 1886. ] Appropriation of the Government Grant. 397 Brouotab formar: (2's desc. «'s £1,122 W. Doberck, for aid in making suflicient Observations to construct Hygrometric Tables for use with Rotating Ther- FECES. AF AIMS A STS Rt cea UN REM cone Dcmeany! cris! A 100 W.W. Haldane Gee, for determining certain Magnetic Con- stants of Iron, Nickel, and Cobalt, and their alloys; especially to investigate the temperature coefficients of magnets made from the materials .......... i of ecard SA Saes WS ao, clear alsfonat sy hale “eaten 20 Dr. D. Gill, for constructing an improved apparatus for Pho- Peomeamenior Stary Maps! . . so... oe viele eo svn vis vaviaee Senate cles 100 W. F. Denning, for observation of Shooting Stars, and of their radiant points, with special reference to the long duration and stationary position of many meteor showers ............ 40 G. J. Symons, for studying the Barometric Oscillations of short period which occur only during thunderstorms ........ 22 G. J. Symons, for renewing Rain-gauges on certain mountains in the English Lake District, and in Wales ’................ 30 J. H. Poynting, for the determination of the Mean Density Bede larth by the ordinary balance.............sssc.+.+« 40 The Heclipse Committee of the Royal Society, towards the expenses of the Hclipse (1886) Expedition ................ 400 The Pendulum Committee of the Royal Society, for the expense of Pendulum Observations to be made at the Kew De eer A NUVI Se oe o.5).m, . 5. i's hs cdo caf $04) 6) 6 mse, #1 ol ei aie. S syste Oia) ora ahs 150 G. R. Vine, for further work upon and descriptions of _ British Fossil Polyzoa and other organisms ............ eo S. J. Hickson, for the hire of boats and labour in the pur- suit of work upon the Anatomy and Development of Maille- PeAMCUC He ear Metals arate sbeliteliatclt c\ielelahs alee) o « «es 6) Hie) ej-alein ae wi)s olais 100 H. T. Stainton, in aid of pabiGabon fund of the Zoological PEC OMOP ASSOCIA UIOM es l''s\che) ci aforay el bles) a des o0)e 0 teen sia 00 oa ele ee — 100 J. Starkie Gardner, for concluding investigations into the Fossil Floras of the Basaltic Formations of Ireland and eM HINER 01 hese) ch at's 61 2) eh ota: ov chop Sata eal aliaialg: at a) 2:6 0)'al 2 s)ayel di oie. 0 secant 50 The Liverpool Marine Biology Committee, for the exploration of the Sea Bottom by Dredgings in Liverpool Bay and the sR ONE TC OCR tees chat: Lav aeieter ale Lovee) #1 4 wheels) el siepeis) v0) +/5.5 Ste lays 25 W. C. McIntosh, for continuation of Researches on the ova and development of the Food and other Fishes, and on the feproduction of the Common Mussel ..........5.......00%: 100 Percy F. Kendall, for the exploration by excavation and the removal to Manchester of a large quantity of the Clay of the recently discovered Pliocene deposit of St. Hrth, Cornwall 30 Carmriedshonwatd yee. 4 s6' 50 «nie 2% £2,454, 398 Appropriation of the Government Grant. [| Nov. 30, Brought forward...... oes e a ol meet W. Bateson, for an investigation of the Fauna of the fresh- water and salt Lakes of the Steppes lying to the North of the den OF Aral’. ..'. 0 eee ee ehs ea oe ee ce ee eee BAIA 200 Rey. A. E. Eaton, for cost of illustrations of Terrestrial Tsopod, Crustacea ............- oie ale ei ae.ole bite giole She are 100 J. T. Cunningham, for continuing a Research on the Development of Marine Teleostean Fishes, and of Myzine GUULVWOSE L. o 2's 1s o's lol stem reine + © oho v\e)eis fo )ale lo aie's) 5 le i 100 Dr. P. F. Frankland, for pparathn and ‘cherwi@ate to be used in his investigations on the Micro-organisms in Air and Wiser £5.) (Wile). RPK suc S' ols lee'e ee vle wleidclse Jules ae a 20 Spencer Pickering, for further investigations on Molecular CompoundsiyPeuent 2 er eh 2 ee eee 100 Prof. W. K. Parker, for continuation of Researches into the Morphology of the Vertebrata..............s2c06 hs > > 00 Prof. T. Rupert Jones, for examination and description of the Fossil Entomostraca (Ostracoda) ......... ose scien eee ane £3,374 = Dr. Cr, 18s. 4d £ d. To Grant from Treasury ....... 4,000 0 0| By Balance over- To Repayment.........« wseee 47 6 8] drawn, Noy. 30,1885 301 12 5 To Interest on Deposit.......+. 312 0 | By Appropriations, as aDOVE . sss sa ee See 3,374 0 0 Printing, Postage, Ad- vertising, and other Administrative Ex- PENSES .. ois os 4 eis sul soe By Balance on hand, Nov. 80,1886 .... 27915 4 £4,050 18 3 £4,050 18 3 1886. | Account of Grants from the Donation Fund. 399 Account of Grants from the Donation Fund in 1885-86.. Mr. W. W. Watts, for a research on the Petrology of Prewvorcame Locks of Corndom |. (0000/0 6.0cce5 sence oe Mr. Norman Collie, for a research on the action of Hydrochloric Acid, and Haloid compounds of Hydro- carbon radicles, on the Amide of Acetoacetic Ethyl ther Dr. Cash, for an inquiry on Intestinal Movements .... Dr. Gaskell, to assist in his researches on the relation of the cranial to the spinal Nerves, and on the anatomy of Be ee TEIN OL VESi 1/2) sichtsolsieis. slel«! Fovast'el sv olelni wie ie''s 0% @ ele are Prof. Schafer and Mr. J. R. Bradford, for a research upon the electrical conditions of secreting Glands ...... Rev. 8. J. Perry and Prof. Balfour Stewart, to assist in their comparison of the (on ae Curves of Kew and rr epnyeg AG Bare, are ciepel ee shovel ols opitaneis ose a\'sj/0/06 oism «eis 6) 6)s/4 ahs Captain Absey) for fhe ee ichses of the Bakerian UR aP UI Me EN eVohe cy TS Stree A alerls <2 ele wie’ sv eieiae!' 4) eis «0 wales : Mr. Crookes, for aid in his researches on Yttria ...... Prof. Rupert Jones, for illustrations of the Fossil Hnto- eA (OSUEACOM )io's « sieo cg ecincisisieice ¢o0 a veces ee cioe Dr. McMunn, for purchase of a Microspectroscope with a view to further examination of the Spectra of the organs PME OMSL Ol ANIMA 21 IS tid lee cole, < ofele so sieic « ou oles) Dr. Cash, for a pharmacological investigation into the action of some of the Aromatic Compounds which have Srmatanen Ween EXaININE Cis. sf Hated ce e's Jeeves cae sacie's Mr. G. J. Symons, towards the cost of Thermometric Observations on the tower of Lincoln Minster .......... Mr. Sherrington, for aid to pursue in Italy the researches on Cholera, in which he was engaged in Spain in conjuuc- Seem eM Ol, VOW! ie suevepeleu cpstiol oo) 0) i's) «1 2) 0) 2's, sviehehal elie ei of" Mr. Warren de la Rue, for the completing of his Cata- logue of Latitudes and Longitudes of Solar Spots, £200. On account. . BS Ge toy, OF O Toe Oe 0 Loe On 6 30 0 O 25 0 0 3027 O80 PA SO (0) SOR kK Ope 0) Sy 0) a) 12 10 O 20 O70 20 0 0 100 0 O a) OO = £414 10 0 Report of the Kew Committee for the Year ending October 31, 1886. The operations of The Kew Observatory, in the Old Deer Park, Richmond, Surrey, are controlled by the Kew Committee, which is constituted as follows: Captain W. de W. Abney, R.H.| The Earl of Rosse. Mr. Warren de la Rue, Chairman. Prof. W. G. Adams. Mr. R. H. Scott. Prof. G. C. Foster. Lieut.-General W. J. Smythe. Mr. ¥. Galton. Lieut.-Gen. R. Strachey, C.S.I. Admiral Sir G. H. Richards, Lieut.-General J. T. Walker, K.C.B. ; C.B. The Committee regret to announce the death, in December last, of one of their members, Captain Sir F. Evans, K.C.B., formerly Hydrographer. He had held a seat upon the Committee since 1874, and was a frequent attendant at their meetings, rendering most _ valuable assistance in all questions relating to terrestrial magnetism or navigation brought forward for consideration. The work at the Observatory may be considered under the fol- lowing heads :— 1st. 2nd. 3rd. Ath. Dil. 6th. 7th. Magnetic observations. Meteorological observations. Solar observations. Experimental, in connexion with any of the above depart- ments. Verification of instruments. Rating of Watches and Marine Chronometers. Miscellaneous. I. Macnetic OBSERVATIONS. The Magnetographs have been in constant operation during the year, and in accordance with the usual practice, determinations of the scale values of all the instruments were made early in January. Report of the Kew Committee. 401 The Vertical Force Balance Magnet was found to have a scale value of for 1 inch 6V=0'0296, and therefore appeared wanting in sensitiveness, it was accordingly re-adjusted and brought up to the proper pitch of delicacy. The values of the ordinates of the different photographic curves determined then were as follows :— Declination: 1 inch=0° 22'04. 1 cem.=0° 8’°7. Bifilar, January 11, 1886, for 1 inch 6H=0°0268 foot grain unit. et ems. == 00005 C.Gn5..umite Balance, January 19,1886 ,, 1 inch 6V=0-0274 foot grain unit. 30 Liem, -==0:0005. C.G.Sunis. The chief days on which notable magnetic disturbance was recorded were as follows :—January 9, March 30, July 27, and October 7-11. The magnetic instruments have been studied, and a knowledge of their manipulation obtained by Professor L. M. Russell, Mr. E. Kitto, and Mr. C. Chambers, jun. Professors Riicker and Thorpe visited the Observatory in April, and made several sets of observations with the instruments which they have employed in their magnetic survey of the British Isles, prior to their commencing operations on the southern section, which have occupied them during the past summer. At the request of the Royal Cornwall Polytechnic Society, a set of magnetographs on an improved model has been constructed for the Committee by Mr. Munro, which, after a lengthened trial in the Verification House, were forwarded to Falmouth, and erected at the New Observatory, under the supervision of Mr. T. W. Baker. The cost has been defrayed by a grant from the Royal Society’s Govern- ment Fund. At the suggestion of General Sir J. H. Lefroy, the Committee have caused a plate to be engraved on which sectional lines are laid down on the scale adopted by the International Polar Conference, for plotting all magnetic curves on a uniform system. Impressions from this plate will be kept at the Observatory, and supplied at cost price to persons desirous of making use of such forms. Information on matters relating to terrestrial magnetism and various data, have been supplied to Professor W. G. Adams, Dr. Atkinson, General Sir J. H. Lefroy, Professor B. Stewart, M. Moureau, Captain Schiick, and others. The monthly observations with the absolute instruments have been made as usual, and the results are given in the tables forming Appendix I of this Report. The following is a summary of the number of magnetic observations made during the year :— 402 Report of the Kew Committee. Determinations of Horizontal Intensity........ 30 - Inclination: (5 thm. oY een 155 Absolute Declination........ 36 2 The diurnal range of the Declination having become a somewhat interesting feature in magnetic reductions, an additional table, giving the values for the summer and winter seasons and for the whole year, as determined from selected curves by the graphic method,* has been inserted in the Appendix. ine METEOROLOGICAL OBSERVATIONS. The several self-recording instruments for the continuous registra- tion respectively of atmospheric pressure, temperature, and humidity, wind (direction and velocity), bright sunshine, and rain, have been maintained in regular operation throughout the year. The only alterations made in the above instruments have been the following: a screen of blue glass has been interposed in the baro- graph between the barometer tube and the light, with the result of improving the definition of the photographic curve, and a Stonyhurst lifter has been fitted to the Beckley rain-gauge, causing the pencil to return to its original position after depression more rapidly than it did previously. The standard eye observations for the control of the automatic records have been duly registered during the year, together with the daily observations in connexion with the U.S. Signal Service synchronous system. A summary of these observations is given in Appendix II. The tabulation of the meteorological traces has been regularly carried on, and copies of these, as well as of the eye observations, with notes of weather, cloud, and sunshine have been transmitted to the Meteorological Office. The terrestrial radiation thermometer (grass minimum) was found broken on July 11, and replaced by a new instrument on July 21. The following is a summary of the number of meteorological obser- vations made during the past year :— Readings of standard barometer .............. 1725 e dry and wet thermometers........ 3450 i maximum and minimum thermo- MIObETH OL. cae ees Latlsiw ak eee eee 730 ss radiation thermometers .......... 1480 ms TAIN PAVGES 4.7. elec sles skies epee ote 730 Cloud and weather observations .............4. 1877 Measurements of barograph curves........... . 8751 * See paper by Mr. Whipple in the ‘Quart. Jour. Roy. Met. Soc.,’ vol. 9, p. 45. Report of the Kew Committee. 403 Measurements of dry bulb thermograph curves... 9473 wet bulb thermograph curves... 8681 wind (direction and velocity)... 17515 yammiall Curves J... .esecc sacs 740 Sunshine traces sss). Soe sek: sae 2113 In compliance with the usual request made by the Meteorological Council to the Committee, Mr. Whipple visited the Observatories at Aberdeen, Glasgow, and Stonyhurst, and the anemograph at Swan- bister. He also superintended the erection of new instruments at North Shields and Fleetwood. Mr. Baker has visited the Valencia and Falmouth Observatories for the purpose of inspection. ' With the sanction of the Meteorological Council, weekly abstracts of the Meteorological results have been regularly forwarded to, and published by ‘The Times’ and ‘The Torquay Directory.’ Data have also been supplied to the Council of the Royal Meteorological Society, the editor of ‘ Symons’s Mouthly Meteorological Magazine,’ the Secretary of the Institute of Mining Hngineers, Messrs. B. Latham, Gwilliam, Rowland, and others. The cost of these abstracts is borne by the recipients. Electrograph.—Acting upon the recommendation of the Kew Com- mittee the Meteorological Council have purchased a new quadrant electrometer, constructed on Mr. de la Rue’s principle, with Professor Clifton’s improvements, together with a chloride of silver battery of 60 cells, for the purpose of maintaining the potential of the quadrants at a certain point. By the kindness of the Chairman of the Committee, experiments were made at his laboratory in Portland Place by means of which the scale value of the instrument was determined before it was conveyed to the Observatory, and erected in the place of the Thomson instrument formerly employed. No change has been made in the recording apparatus attached to it. The instrument has been working for the past month in a satis- factory manner. In accordance with a request made by the Meteorological Council, and at their expense, the electrograms for the two years 1882 and 1883 have been tabulated in absolute values. III. Sonar OpsERvATIONS. The sketches of Sun-spots, as seen projected on the photoheliograph sereen, have been made on 169 days, in order to continue Schwabe’s enumeration, the results being given in Appendix II, Table IV. Transit Observations.—3801 observations of solar and 76 of sidereal transits have been taken, for the purpose of keeping correct local time: VOL. XLI. 26 404 Report of the Kew Committee. at the Observatory, and the clocks and chronometers have also been compared daily. The Observatory Chronometers Arnold 86 and Parkinson and Frodsham 2408, have been cleaned and re-adjusted, and the mean-time clocks, Shelton K. O., and Shelton 35, examined and re-adjusted by Dent. The following clocks, French, Dent 2011, Shelton K. O., and the chronometers, Molyneux No. 2125 and Breguet No. 3140, are kept carefully rated as time-keepers at the Observatory. The mean-time clock, Shelton 35, after cleaning, &., was bolted to the wall of the chronometer-room for use in daily comparisons with the chronometers on trial. In order to facilitate the inter-comparison of the clocks, the chronometer “ Parkinson” has been specially fitted up as a “ hack ” instrument. At the request of the Council of the Royal Meteorological Society, certain experiments were made with the view of investigating Professor W. K. Zenger’s solar phenomena and an examination was also made of the Kew solar photographs. The results obtained were however of a negative character only. A note of them has been published in the ‘ Quarterly Journal Roy. Met. Soc.,’ vol. 12, p. 215. A comparative trial extending over five months was made of Professor McLeod’s sunshine recorder (see ‘ Phys. Soc. Proe.,’ vol. 6, p- 216), and the Stokes’ instrument, which proved the results given by the two instruments to be practically identical. ITV. EXPERIMENTAL Work. Photo-nephograph.—The report on last year’s work in cloud pho- tography was duly submitted to the Meteorological Council, and placed by them in the hands of Professor Stokes for consideration. Professor Stokes having investigated the methods employed at the Observatory, devised a new graphic process for determining the cloud heights and motions in a much simpler manner than by the use of mathematical formule only. He invented a special apparatus called a projector, which has been constructed by C. Baker, and is now being utilized in the reduction of the pictures taken during the past season, These have amounted to 112 cloud negatives, and were obtained in 15 days. For convenience of dealing with the cloud pictures in the projec- tion apparatus with greater facility, the negatives have all been printed off on paper prepared by the cyanotype process. Certain minor additions were made to the cameras, and accessory apparatus, which have tended to facilitate their working, and their action has been fairly satisfactory ever since. There is, however, still an occasional failure due to uncertainty of the duration of the Report of the Kew Committee, 409 time of exposure of the twin cameras, although this is apparently instantaneous. Solar Radiation Thermometers—The experiments with these ther- mometers have been continued during the past summer months, and at times as many as 8 instruments have been under observation. It having appeared that during the winter the vacua in certain of the instruments had deteriorated either by leakage or evolution of gas from the lamp-black coating of the bulbs, experiments were made in the Chairman’s laboratory which proved that such was the case. New thermometers were made and enclosed in jackets not provided with platinum electrodes; the bulbs were also made of black glass, having the stems covered with black enamel. These, after careful exhaustion, were placed under observation, but did not register temperatures higher than had been previously observed. Advantage was taken of an offer kindly made by Professor Thorpe to make solar radiation observations on his recent Hclipse Expedition to Grenada, and two of the instruments were lent to him. He has now returned them to the Observatory, together with copies of the readings he was able to procure on the occasion. Hlectrical Anemograph.—This instrument, after a lengthened trial in the Experimental House and the execution of certain minor altera- tions by Mr. Kempe, has been dismounted and forwarded to the Valencia Observatory by instructions of the Meteorological Council. The external parts were previously put into thorough repair by Mr. Munro, in order to fit the anemograph for the rough weather to which it will be exposed when erected on a hill almost overlooking the Atlantic, Dines’ Anemometer.—Trials have been made of two anemometers constructed on a new principle by Mr. W. H. Dines, B.A. Owing, however, to structural defects, both instruments broke down before any final results were obtained, and were returned to the maker for repair. Glycerine Barometer.—This instrument, having very considerably deteriorated by age, was dismounted by Mr. Jordan in June, and after _ thorough cleaning and repair by Mr. J. Steward, was again erected and refilled with new fluid. Pendulum Experiments.—At the request of General Walker, certain experiments were made with the view of ascertaining the stability of the Experimental House as a site for pendulum operations. These having proved that building unsuitable, a wooden erection 13 ft. x 9 ft. x 8 ft. has been constructed, at the desire of the Pendulum Committee of the Royal Society, in the lower South Hall of the Observatory, on the spot occupied in 1873 by Captain Heaviside, when experimenting with the Russian pendulum. (See Report for 1873.) In this room it is the intention to erect the Indian Pendulum Appa- 25 2 406 Report of the Kew Committee. ratus recently returned by Professor Peirce from the United States, and swing the pendulums so as to obtain a differential connexion with recent swings in New York. Subsequently, it is intended to convey the whole to the Royal Observatory at Greenwich, where other series of observations and experiments will be conducted with a view to connecting Greenwich with Kew. At the request of the Meteorclogical Council, various experiments were tried with the view of selecting a suitable paper for use with the Beckley anemographs, and also of remedying certain defects found attendant on the employment of gelatinised photographic curves in processes of mechanical reduction in the Meteorological Office. V. VERIFICATION OF INSTRUMENTS. The following magnetic instruments have been verified, and their constants determined :— 1 Unifilar Magnetometer and an Inclinometer for the Falmouth Observatory. Two Inclinometers have been purchased on commission for the Bureau of Navigation, Washington, 1 each also for the Kkaterinburg Observatory and the Lighthouse Board, Helsingfors. 2 Dip Needles have been procured and tested for the Mauritius Observatory; also 1 pair for the Lisbon Observatory; 7 Thomson’s patent compasses with 7 vertical force instruments have also been examined for the Imperial Japanese Navy. 1 Unifilar, 2 Compasses, and 2 Inclinometers have been tested for opticians, and 2 Unifilars are at present undergoing verification. The total number of other instruments compared in the past year was as follows :— iBbarometers, Mtandard.* 2. s's)<. 2s eee eene 31 as Marine and Station.......... ae 92 NSTC TMINS sai: <2 Ce RIE cons cde eee : 124 Rotal csi beeen 247 Thermometers, ordinary Meteorological ..... 1320 A Standard and Chemical...... 210 as bE RE ETL Fe FO 0 ed ag MINER 2 be ADS Ne Ultnical |. reese. ss ee eee 9054 .. Avibretus 72. .') eee ee 816 Solar radiation .......2.... 45 Report of the Kew Committee. 407 Ree GP. s Salas == Horizontal, with dial up ..... Das 14 days 8 days af Hy ff iby MCLOMMADEL RAT orek: tt Orns — _ i at temp./402 Horst. 6c.. . De. 1 day — 45 op OD ua ee ieee: Deas ile} — NOP TAbed vise. oh em ote Sees | bao — Total duration of test...........00. 45 days 31 days 16 days Owing to the inconvenience and delay attendant on the employ- ment of one safe for both hot and cold tests, a second was procured, and has been fitted up as a refrigerator, thereby enabling two sets of watch trials to proceed simultaneously, and more constant tem- peratures in both heat and cold to be sustained for the necessary periods. Special attention has been given to the examination of pocket chronographs, in accordance with the request of the Cyclists’ Union. Manufacturers have also been advised of certain mechanical defects in the action of the chronograph work, and latterly an improvement has taken place in respect of this. Early in the year a communication was received from the President Report of the Kew Committee. 409 of the Section d’Horlogerie de la Société des Arts 4 Genéve, asking for full particulars of the system of rating at this Observatory. These were forwarded to him, and in acknowledging receipt of the same he expressed the gratification of his Council at the degree of accuracy obtained in the Kew trials during the year. fiating of Chronometers—Application having been made to the Committee to extend their system of watch rating to marine chrono- meters, arrangements were carried out for effecting this. A chrono- meter oven formerly constructed for the Testing Office of the Board of Trade, being unemployed, was obtained on loan from the Meteoro- logical Council, in whose possession it was, and erected with the necessary gas-fittings in the Thermograph-room of the Observatory. A scheme for rating and certifying was drawn up, of which the following is a brief abstract. The trial occupies 35 days, divided into 5 periods of 6 days each, and 5 intermediate days, namely, 1 day at the commencement of each period of test :— Ist period. Chronometer at temperature of 55° F. or 13° C. 2nd $9 99 99 70° 99 24° 29 ord 99 99 99 85° 99 29° 99 4th 99 99 9 70° 9 21° 9 oth 99 99 29 55° 99 13° 99 Certificates are granted to chronometers which have undergone 59 days’ test as specified above, and whose performance is such that :-— 1. The mean of the differences in each stage of the examination, between (a) the average daily rate during that period, and (b) the several daily rates, does not exceed one second in any one of the stages. 2. The mean daily rate has not been affected by change of tem- perature more than one-sixth of a second per 1° F., which is about a quarter of a second per 1°C. 3. The mean daily rate has not exceeded five seconds in any stage of the test. The trials were commenced in August, and up to present date seventeen ordinary marine and one sidereal chronometer have been rated. The Astronomer Royal having on enquiry certified as to the excellent working of Kullberg’s temperature regulator in the chrono- meter oven at the Royal Observatory, Greenwich, the inventor has ‘been instructed to fit a similar one to the Kew testing case. A Richard Thermograph has also been procured, and is arranged to work in the case with the chronometers, so as to afford a continuous 410 Report of the Kew Committee. : record of the temperatures which they have experienced during the whole of their trial. The range of temperature from 55° to 85° F., to which the marine chronometers are submitted, has been decided upon after careful consideration, as being amply sufficient for determining the behaviour of chronometers under conditions to which they are usually exposed at sea, and no objections have yet been received from makers or others to the adoption of the above range. VII. MisceLLANEous. Photographic Paper, §c.—This has been supplied to the Observa- tories at Batavia, Coimbra, Falmouth, Glasgow, Lisbon, Mauritius, Oxford, Stonyhurst, St. Petersburg, and Toronto, and to the Meteoro- logical Office. Blank forms have also been supplied to various Observatories and individuals. | At the request of Senhor Capello, of the Lisbon Observatory, an astronomical clock was procured and shipped to the Loanda Observatory, for use during the recent solar eclipse. Two barograph tabulators, photographic appliances, and various other instruments have been procured, verified, and forwarded to the Observatories at Hong Kong and Mauritius. The Observatory has been presented by the Rev. John Rigaud, B.D., Fellow of Magdalen College, Oxford, with a bust of his father, Stephen Peter Rigaud, Hsq., M.A., F.R.S., Savilian Professor of Astronomy and Radcliffe Observer, who formerly assisted his unele, the Rey. S. Demainbray,.in carrying on the Observatory. Huhibitions, §c.—At the request of the Council of the Royal Meteorological Society a number of old instruments were exhibited at the Hxhibition held by the Society in the rooms of the Institution of Civil Engineers in March, and devoted this year to barometers. Four sets of photographs illustrative cf the various processes in use at different periods at the Observatory have been contributed to the Photographic Exhibition, held in the Corporation Galleries of Art at Glasgow. Inbrary.—In July the Superintendent received a letter from the Secretary of the Royal Society offering a number of duplicate volumes about to be removed from the Library at Burlington House, and forwarding a catalogue. A selection was made of those suitable for the Observatory Library, and sixteen volumes were accordingly sent down to Kew. Presents of publications were received during the year from— 34 Scientific Societies and Institutions of Great Britain and Ire- land, and 92 Foreign and Colonial Scientific Establishments, as well as numerous private individuals. Report of the Kew Committee. A1L Magnetic Reductions —At the request of Professor Balfour Stewart, the Superintendent prepared and submitted to the Committee of the British Association on the Reduction of Magnetic Observations, a report on the comparison between Wild’s, Sabine’s, and the Green- wich methods of determining the solar diurnal range of the decli- nation. Workshop.—The machine tools procured for the use of the Kew Observatory by grants from the Government Grant Fund or the Donation Fund have been kept in thorough order. House, Grounds, and Footpath.—These have all been kept in order during the year. _ Her Majesty’s Commissioners of Woods and Forests have kindly complied with the request of the President and Council of the Royal Society that the Observatory Staff should have a free passage at all hours through the yard tenanted by the lessee of the Old Deer Park, and accordingly an iron turnstile has been erected at the expense of the Committee at the entrance gate to the Park. The necessary external repairs and painting of the building have been carried out by Her Majesty’s Commissioners of Works as usual. Owing to the increase of work now undertaken by the Observatory Staff it has become necessary to consider means of increasing the available accommodation, and of providing more space by addition either to the Observatory building itself or to one of the out- buildings. Plans for both schemes have been submitted to the Committee, together with estimates of the approximate cost. PERSONAL HsraBLISHMENT. The staff employed is as follows :— G. M. Whipple, B.Sc., Superintendent. T. W. Baker, Chief Assistant and Magnetic Observer. H. McLaughlin, Librarian and Accountant. HE. G. Constable, Solar Observations and Rating. W. Hugo, J. Foster, T. Gunter, W. Boxall, H. Dagwell. H. A. Widdowson. F. Oliver. W. C. Gough. H. Redding. M. Baker, Messenger and Care-taker. 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Set seeesaasessacgsbaneeayAWendaaanausin esac hsSssiceseNanensAnenetensss-*< (GOP OG OR OOUB INO On DMO MD Oi teil Qa “‘SLd HOTS ni "JODLGSQ Report of the Kew Committee. 413 APPENDIX TI. Magnetic Observations made at the Kew Observatory, Lat. 51° 28' 6" N. Long. 0° 1" 151 W., for the year October 1885 to September 1886. The observations of Deflection and Vibration given in the annexed © Tables were all made with the Collimator Magnet marked K C 1, and the Kew 9-inch Unifilar Magnetometer by Jones. The Declination observations have also been made with the same Magnetometer, Collimator Magnets 101 B and N E being employed for the purpose. The Dip observations were made with Dip-circle Barrow No. 33, the needles 1 and 2 only being used; these are 34 inches in length. The results of the observations of Deflection and Vibration give the values of the Horizontal Force, which, being combined with the Dip observations, furnish the Vertical and Total Forces. These are expressed in both English and metrical scales—the unit in the first being one foot, one second of mean solar time, and one grain; and in the other one millimetre, one second of time, and one milligramme, the factor for reducing the English to metric values being 0°46108. By request, the corresponding values in C.G.S. measure are also given. The value of log z*K emplceyed in the reduction is 1:64365 at tem- perature 60° F. The induction-coefficient pw is 0°000194. The correction of the magnetic power for temperature ¢, to an adopted standard temperature of 35° F’. is 0:0001194:(¢4, —35) + 0:000,000,213(¢,—35)?. The true distances between the centres of the deflecting and deflected magnets, when the former is placed at the divisions of the deflection- bar marked 1:0 foot and 1°3 feet, are 1:000075 feet and 1°:300097 feet respectively. The times of vibration given in the Table are each derived from the mean of 12 or 14 observations of the time occupied by the magnet in making 100 vibrations, corrections being applied for the torsion-force of the suspension-thread subsequently. No corrections have been made for rate of chronometer or arc of vibration, these being always very small. The value of the constant P, employed in the formula of reduction a2 (1, is —0-00148, eX’ To" In each observation of absolute Declination the instrumental read- ings have been referred to marks made upon the stone obelisk erected 1,250 feet north of the Observatory as a meridian mark, the orientation of which, with respect to the Magnetometer, was determined by the late Mr. Welsh, and has since been carefully verified. The observations have been made and reduced by Mr. T. W. Baker. 4l4 Month, | 1885. Octobery Ze: sos December 22...... RS AT SLL TS ie Mean .. ... 1886. January 26...... Ohi es eoeee Mean... oc February 22...... 23. 26... 0. Report of the Kew Committee. Table I. Observations of Inclination. Mean inclination. Month. 1886. April Dick asian 29, Mean...... May Pita ooo: 26). Mean. eric June DA ardeaene 266 «sree Mean...... July 2 yaegee OF eves eeee Mean.... August 23...... DA eae Mean..... September 23..... 22a ala. Mean inclination. 67 36°8 67 87-2 Report of the Kew Committee. Table II. Observations for the Absolute Measure of Horizontal Force. Value of m*. Month. Log x ec Be mean. 1885. October 29th and 30th . 9°12250 0° 30825 November 26th ........ 9 °12195 0 °30872 December 29th.......... 9 :12187 0 30874: 1886. SPAMGEEY ASE. 6.66 oe veins 9 °12154, 0 °380902 February 24th ......... 912184 0 °30923 Masel) 2300 ee 9°12221 0 °30860 April Ist and 2nd........ 9 -12230 0 -30865 eG IY eho. iw Secete 6 oe 9 -12086 0: 380800 Mle nth... ssc. cepe ec) >) 9712108 0 -30932 June 28th . eae 3 9°12095 0° 30836 July 23rd .. Bre ae As, Gea ae 9°12171 -30807 Mimustyeoths. .oc. 2 ck. 9 -12193 0°30775 September 27th ,........ 9°12122 0 °30823 Sagoo ee]S oo-S *51925 *61919 °61916 51913 51943 *01928 61937 “61812 “ol901L °51838 *51867 61861 51847 Table I1I.—Solar Diurnal Range of the Declination. H Summer Winter Annual our. mean. mean. mean. fi d / 0 +5°6 +2°9 +4:°3 1 +6°8 +4°8 +5°8 2 +6°0 +44 +5°2 3 +5°0 +3°5 +4°3 4, +2°8 +1°5 +2°2 5 +1°8 +0°6 +1°2 6 O4 —0°5 Ord 7 —0-2 —0°4 —0°'3 8 (3: = 11 —0°7 9 —0°3 —0O°9 —0°6 10 er OS) oR —1'1 11 == (rar —1°3 —1:°0 12 — 150 = 1108? —1°2 13 — "2 —1:1 —1°2 14 —2°0 —0°8 —1°4 15 —2:°2 —0°4 —1°3 16 —2°5 —0°8 —1°7 7 —3°:0 —0°7 —1°'9 18 —3°8 -0°9 —2°4 19 —4:°0 —1°3 —2°7 20 —4°2 —1°5 —2:°9 21 —3°5 —2°1 —2°8 22 —1°5 —1°7 —1°6 23 +1°8 +0°8 +1°3 * m=moment of vibrating magnet. 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APPENDIX IV. List of Instruments, Apparatus, &c., the Property of the Kew Com- mittee, at the present date out of the custody of the Superintendent, on Loan. Date To whom lent. Articles. of loan. —— | ee G. J. Symons, F.R.S. | Old Kew Thermometer Screen ..............| 1868 Portable Transit Instrument...... we: lbv atetiatelte 1869 The Science and Art| The articles specified in the list in the Annual} 1876 Department, South Report for 1876, with the exception of the Kensington. Photo-Heliograph, Pendulum Apparatus, Dip-Cirele, Unifilar, and Hodgkinson’s Acti- nometer. Dr. T. Thorpe, F.R.S.| Three Open Scale Standard Thermometers,| 1879 Nos. 561, 562, and 563. Tripod Stand....... PO NAMA ie. oc 1883 Lieutenant A.Gordon,| Unifilar Magnetometer by Jones, No. 102,| 1883 R.N. complete, with three Magnets and Deflection Bar. Dip-Circle, by Barrow, one Pair of Needles, and Magnetizing Bars. One Bifilar Magnetometer. One Declinometer. Two Tripod Stands. General Sir H. Lefroy, Toronto Daily Registers for 1850-3 .........| 1885 | R.A., F.B.S. Professor W. Grylls | Unifilar Magnetometer, by Jones, No. 101,| 1883 Adams, F.R.S8. complete. Professor O. J. Lodge ; Unifilar Magnetometer, by Jones, No. 106,| 1883 complete. Barrow Dip-Circle, No. 23, with two Needles, and Magnetizing Bars. Tripod Stand. Mr. W. F. Harrison .| Condensing lens and copper lamp chimney ..} 1883 Captain W. de W.| Mason’s Hygrometer, by Jones .............| 1885 Abney, F.R.S. Professor Rucker... Tripod stand sa staes» «<5. 020 > dls weleeiee nn eS The Minute Anatomy of the Brachial Plezus. 423 “The Minute Anatomy of the Brachial Plexus.” By W. P. HERRINGHAM, M.B., M.R.C.P. Communicated by W. S. Savory, F.R.S. Received March 8,—Read March 25, 1886. It has for some time appeared probable that the spinal nerves which form the brachial plexus do not become confounded one with another, but retain each its separate course and its separate functions. To the naked eye a nerve is a bundle of parallel threads bound together, and at the same time divided by a sheath of connective tissue. It seemed to me possible that the course of the spinal nerve roots could be traced by a dissection which should follow each through the plexus to the nerves which branch therefrom, and in these to its final destination. My dissections were partly upon foetuses or stillborn children, partly upon theadult. The plexus of an infant is in some: respects better, in some worse than that of an adult for an investigation of this kind. On the one hand its minuteness needs the confirmation of larger tissues, but on the other hand the fibrous sheath uniting the nerves is very. much weaker and less perfect, so that as in the case of the pectorals, the serratus magnus, and coraco-brachialis muscles, arrange- ments which in the adult need great care in dissection, can be seen in the infant without using the knife at all. Adult bodies are best fitted for tracing fibres down a long nerve. The present paper is based upon the dissection of fifty-five plexuses, thirty-two being foetal or infantile, and twenty-three adult. The 5th cervical nerve as it lies between the scaleni gives off a branch which divides into the nerve to the rhomboids, and the upper root: of the posterior thoracic. The latter is joined by the root from the 6th, and lower down by one or sometimes two branches from the 7th. In the adult the 5th and 6th usually join before the first digitations of the serratus magnus are reached, and receive the 7th about the level of the first rib. It can generally, even in adults, be seen that the 7th joins the nerve below the twig given to the first part of the muscle formed by the two upper digitations, and it is often easy to separate the 5th from the 6th, and this from the 7th, so far as to show that the first part of the muscle is supplied wholly by the 5th, and the second by the 6th alone, or by the 5th and 6th, while the 7th does not give twigs until the third part is reached. I have several times been able to show this to students in the dissecting room. But in the foetus there is no dissection necessary. The branch to the first part is given off before the 5th reaches the 6th, and the 7th does not enter 424 Mr. W. P. Herringham. the nerve until it has descended to the third or lowest part of the muscle. The connective tissue which in the adult binds all the nerve together has not in the foetus yet grown up, and the system of the nerve is naturally exposed. ‘The supply of each nerve is variable. If the dth root is large it will send on fibres to supply with the 6th the middle of the muscle. If it is small it spends itself entirely on the upper part, but however the different roots may vary in size I have never in the numerous dissections I have made seen them alter their relative positions. Two typical examples from adults may be quoted. In one, the 5th gave twigs to the first three digitations, and then a small fibre to the 6th. There was no root from the 7th. Inthe other, the 5th supplied the first two, the 6th alone supplied the next two, and the 6th and /th the remaining digitations. In these there was no splitting of the nerve necessary. The drawings shown were made from them. Diagrammatic Sketch of Posterior Thoracic from two Adults. V, VI, VII=Branches from 5th, 6th, and 7th roots. 1, 2, 3= First, second, and third parts of serratus magnus. As the 5th leaves the scaleni it receives a communicating branch from the 4th, which therefore does not enter the rhomboid branch, or the posterior thoracic. The communicating branch varies consider- ably in size, Ihave at times been scarcely able to recognise the twig, at others it is a sixteenth of an inch thick. In the remainder of the paper this branch is not separated from the oth. Soon after this the 5th root joins with the 6th. It is usually at their junction that the swprascapular nerve is given off, but it is not The Minute Anatomy of the Brachial Plexus. 425 uncommon to find it springing from the 5th before the junction is made. When this is the case it contains no fibres from the 6th, but when given off at the junction it usually, though not always, receives a minute fibre from the 6th which passes either behind or through the fibres of the 5th to reach the suprascapular. The 6th therefore exercises sometimes an extremely small influence, and sometimes none at all over the supra- and infra-spinatus. The united 5th and 6th then divide into an anterior and a posterior branch.* The anterior joins with an anterior branch of the 7th to form the outer cord. Just before their junction the united 5th and 6th gives off one, and the 7th two branches for the pectorals. The upper branch from the 7th joins with that from the 5th and 6th to form the external anterior thoracic, which, piercing the costo-coracoid membrane, supplies the clavicular and the upper piece of the sternal part of the muscle as far down as the fibres which arise from the 2nd costal cartilage. The lower 7th branch forms that which is usually called the commumn- cating branch of the external anterior thoracic. It has, however, a separate origin from the 7th trunk, and contains no fibre of the 5th or Diagram of Anterior Thoracics. Fie. 3.—As seen in Adults. Fig. 4.—As seen in a Feetus. y/ yi x \ xX 9 SY 25 V+VI. VI. VIW+IX. V+Vi. VII. VIN +IX. Ny \ V, VI, VII, VIII, [X=5th, 6th, 7th, 8th cervical and 1st dorsal roots. V+ VI, VIII+1X=Trunks formed by union of these roots. a= Twigs to clavicular division of pectoralis major. 6, ec, d=Twigs to upper, middle, and lower parts of the sternal divi- sion of the muscle. X=“ Communicating branch,” of which X, goes over, X, under, the pectoralis minor. 6th. It runs under the costo-coracoid membrane over the axillary artery, and at the upper border of the pectoralis minor divides into two, of which one branch passes in front, running with the branches * Or the nerves may each divide before they join. 426 Mr. W. P. Herringham. of the acromial thoracic artery, to supply the pectoralis major; the other goes behind the pectoralis minor, sends two twigs through it which supply it and the next parts of the pectoralis major, and close to the lower border of the muscle joins with the internal anterior thoracic which appears from under the artery. The united nerve now supplies the lowest part of the pectoralis minor, and turning round its edge serves the lowest fibres of the pectoralis major. This arrangement was constant in eight consecutive adult cases that I dissected. I was, however, able in one of the foetal dissections to see more than this. The branch from the 5th and 6th, before joining the branch from the 7th, gave a twig which ran to the clavicular portion and which alone supplied that part. The union of the 5th, 6th, and 7th supplied the upper part of the sternal muscle. The 7th served the middle as in the adult, but the internal anterior thoracic before receiving the 7th gave off a twig which supplied the lowest fibres of the pectoralis major, its union with the 7th serving the fibre next in order above these. Of the nerves interested in the anterior thoracics the 7th always contributes. Of thirteen dissections the 5th and 6th both gave branches to the external in five, the 6th alone in eight cases. Of ten dissections the 8th and 9th both gave branches to the internal in eight cases, the 8th alone in two. It appears, therefore, that the pectoralis major does not usually receive from the 5th, and does usually receive from the 9th.* Below these branches the 7th joins the 5th and 6th, thus forming the outer cord, which bifurcates into the musculo-cutaneous and the outer head of the median. I have seen three cases where the musculo- cutaneous when about to pass under the biceps to the outer side of the arm gave back a large bundle to the median. ‘Two of these cases were adult, and in them the returned bundle consisted in one wholly of the 6th root, in the other of fibres from both 6th and 7th. The musculo-cutaneous 1s usually described as supplying the coraco- brachialis. In the adult the nerve to this muscle is given off before the musculo-cutaneous enters it. If traced up it is seen to come from the outer cord before the musculo-cutaneous leaves it, and ultimately from the 7th root in the outer cord. It passes under the cord to get to the muscle. Here again the system is very much clearer in the foetus, for in the foetal plexus the coraco-brachial nerve can be seen running from the 7th before it joins the 5th and 6th, and passing under the 5th and * The first dorsal I have here called, and shall henceforth call, the 9th spinal root, the 2nd and 3rd dorsal the 10th and 11th respectively. The 9th receives at its origin a small branch from the 10th in the majority of cases. It is too small to dissect in the foetus, and the conditions of a dissecting room do not allow of its dissection in the adult. I have therefore included it in the 9th root. The Minute Anatomy of the Brachial Plexus. 427 6th to reach the muscle. It is therefore quite distinct not only from the musculo-cutaneous, but from the 5th and 6th also. I have found this arrangement constant in the foetus in more than twelve consecu- tive cases, in fact ever since I first recognised it. I have also seen it in the adult. In one case, however, I found the muscle supplied not only by this nerve from the 7th, but also by a fibre from the 6th in the musculo- cutaneous. The rest of the musculo-cutaneous, or as should be said, the musculo- cutaneous nerve proper, hardly ever contains any fibres other than those of the 5th and 6th. In thirty-nine cases, twenty-one foetal and eighteen adult, the 7th only contributed to the musculo-cutaneous four times, twice in the foetus, and twice in the adult. Of these four exceptions, in two the 7th could not be traced down the nerve, in a third it ran to the short head of the biceps, and in the fourth, an adult case, it entered the cutaneous branch only. Twenty-eight cases were examined to see if both 5th and 6th entered the nerve. In twenty-seven this was found to be the fact, in one, only the 5th was traced into it. In eight cases the 5th and 6th were traced down the nerve. Four of these were foetal, and four were adult. The biceps was found to be served by both 5th and 6th in seven instances, in one the 5th alone was traced to the muscle. The brachialis anticus was supplied by both the 5th and 6th in four cases, and by the 5th alone in four. The cutaneous branch was found to contain fibres from both roots in Six cases; in one it was formed by the 6th and 7th. The bundle from the 5th was noted as very small in two cases, and in two more was found to supply the skin over the outer condyle and the head of the radius, the nerve in the forearm being wholly derived from the 6th root. In another case it ran down the forearm over the flexor carpi radialis in front of the branches from the 6th. The remaining nerve given from the outer cord is the outer head of the median. Into this the 5th does not enter. Thirty-one dissections showed no exception to this rule. The supply of the oth by its anterior branch ends therefore with the musculo-cutaneous nerve. The median is formed by two heads; into the outer the 6th and 7th always enter, while the inner is formed always by branches of the 8th and 9th, sometimes with the addition of some bundles of the 7th. This variety depends upon whether the anterior branch of the 7th bifurcates or goes wholly to the outer cord. In order to see whether both 8th and 9th contribute to the median, twenty-eight dissections were made, fourteen in infants, fourteen in adults. In one foetus, and in one adult, no branch from the 9th was found. These two were, however, the only exceptions to the rule that both roots send . fibres to the nerve. The median then is made of the 6th, 7th, 8th, 428 Mr. W. P. Herringham. and 9th. But these roots do not send to it a constant proportion. There is little variation in the size of the 6th bundle, the 7th varies considerably, the 8th is sometimes equal to, sometimes smaller than, and sometimes larger than the 9th. The 6th bundle runs down the outer side of the nerve from the top to the bottom, though in dissection the nerve generally becomes so twisted that 1t seems otherwise. In the lower third of the arm a pair of fibres are seen crossing from the outer to the inner side. These are the nerves to the pronator teres and the flexor carpi radialis. They are given off almost always by the 6th, and they usually run over in front of the nerve to reach the muscles. I have, however, dissected them running through the nerve and separating the other bundles. The nerve to the pronator usually divides into two before it reaches the muscle, and is sometimes double from the beginning. With the nerve to the flexor carpi radialis runs a nerve to the other flexors, but this comes from a lower root. In eight cases where the 6th and 7th were not separated, these two muscles were supplied by the combined bundle. The nerve to the pronator teres was traced seventeen times to the 6th, once to the 7th; that to the flexor carpi radialis thirteen times to the 6th, twice to the 7th; neither to any other nerve. The 6th does not supply any other muscles in the forearm. The 7th was traced nine times to the flexor sublimis, and in four of these it also contributed to the anterior interosseous. It is to be noted that in two of these four it also formed part of the ulnar. Of the five cases when it did not go to the anterior interosseous the ulnar was traced in four, and did not in any of these receive from the 7th. Where then the 7th goes to the anterior interosseous it is probable that it will form also part of the ulnar; when it is excluded from the ulnar it probably does not contribute to the anterior interosseous. In seven cases no branch could be traced to the flexor sublimis. The 8th and 9th usually supply the flexor sublimis, and always the deep flexors. In seventeen instances the flexor sublimis received from them fourteen times, and three times did not receive from them. The two nerves were separated six times in adults, with the result that they seemed to mingie in all muscular branches in the forearm, and that no muscle could be said to belong to the one and not to the other. After the forearm muscles have been supplied, the remainder of the median which comes from under the flexor sublimis always con- tains fibres from the 6th, 7th, and 8th roots, and sometimes a bundle from the 9th. The 6th was traced separately eleven times, and the /th seven times in this part of the nerve. Neither was ever found absent. The distribution of the lower two roots in the hand was traced in eleven cases. In six of these they were not separated; in the other five the | Lhe Minute Anatomy of the Brachial Pleas. 429 9th ran to the hand in two only; in three of these, and in one other case, it was seen to end in the muscles of the forearm. Of these six cases two were foetal, the rest adult. The 8th always ran to the hand. As arule then the median in the hand contains only fibres from the 6th, 7th, and 8th. The palmar cutaneous branch was five times noted, twice coming from the 6th, three times from the 7th. The branch to the superficial muscles of the thumb was eleven times dissected. In eight cases it came from the 6th, in three from the undivided 6th and 7th, never from the 8th or 9th. The five digital branches* were more variously distributed. The first branch was traced fourteen times, nine times to the 6th, and five times to the united 6th and 7th. The second was traced fourteen times, six times to the 6th, five times to a united 6th and 7th, twice to both 6th and 7th, and once to the 7th alone. The third was traced eleven times, twice to the 6th, five times to a united 6th and 7th, once to both 6th and 7th, and thrice to the 7th. The fourth was traced eleven times, once to a united 6th and 7th, three times to the 7th, twice to the 8th, once to a united 8th and 9th, and in four the radial side of the cleft was supplied by the /th or the united 6th and 7th, and the ulnar side by the lower nerves. The 5th was traced eleven times; in one the 7th served the radial side of the cleft, the other side being supplied by the united 8th and 9th, in three the 8th alone, in five the undivided 8th and 9th, in one both 8th aud 9th (the latter taking the ulnar half), and in one the 9th alone supplied it. These figures are confusing to read, but the table shows that the first branch is always supplied by the highest nerve, the last always from one of the lowest, and that in no case is there a break in the order of supply from the one to the other. No. of case. dle 2. 3. A. Dy 13. Digital branches. Per ae, teres ate 6 6 6 Fy a) Ae 6+ 7+ 6 64+7 647 y 6 ee ed yc 7 of ea Ais OTA eM (E Ror one aM MOF fer an) 8 6+7,849 | 8+9 aie Seen ae 84+9 8+9 9 84+9 84+9 * Ist, radial side of thumb; 2nd, ulnar ditto; 8rd, radial of index; 4th, cleft between index and 3rd finger; 5th, cleft betwten 3rd and 4th finger. + The sign + means that the two nerves were not separated. In Case 1 the first three branches arose from the bundle formed by the union of the 6th and 7th, the fourth had two roots, one from the 7th alone, the other from the bundle formed by the union of the 8th and 9th. 430 _ Mr. W. P. Herrmgham. | No. of case. 14, aD. HRY 42. 43. 52. 53. | 54. Digital branches. | BY ie amie vcheohoue ts 6 6 6 6 6 6 vin PONE. 6 6 6 6 6.7%. 1 Sar 6+7 pas ssh ed hS gig uitog paling bad | Aa ce deiae ne 7 7 8 i 6+7,8 | aT ea 7,8+9 8 8,9 8 | 8+9 The origin of the ulnar nerve was traced in thirty-two cases, of which fourteen were adult. It was found to arise in four different ways. Its most common origin is from the 8th and 9th together. This occurred in twenty- three cases, eleven foetal and twelve adult. With these is sometimes combined a strand from the 7th, as shown in five cases, four feetal and one adult. In three foetal cases it arose from the 8th only, and in one foetal, and one adult case from the 7th and 8th. The 7th is only added to the nerve in some of those cases where it gives a branch to the inner cord. In several cases the branch from the 8th was much larger than that from the 9th. I have never seen the reverse. The nerve was split down in seven instances, of which two were foetal. One of these had fibres of the 7th in it which, however, were not traced separately. Branches were traced to the muscles of the forearm from both nerves in five cases, in two from the 8th alone. The anterior cutaneous branches were in four cases from the 9th, in one apparently from the 8th. The dorsal cutaneous was in all seven a branch of the 8th. The superficial division in the hand going to the fingers was traced in all, and in three contained fibres from both 8th and 9th, in the other four was wholly from the 9th, while the deep or muscular branch traced in six was in five wholly from the 8th, and in the sixth received also from the 9th. According then to these dissections the 8th and 9th usually both supply the forearm muscles, the 8th gives the dorsal cutaneous, and serves the intrinsic muscles of the hand, while the 9th gives sensation to the skin on the palmar surface of the hand, and of the lower third of the forearm. The origin of the ¢nternal cutaneous was noted twenty-three times in my dissections. Nine times it contained a fibre from the 8th as well as the 9th, fourteen times it sprang from the 9th alone. In two cases of the former class the 8th was separated from the 9th in the nerve. In the one the 9th alone supplied the skin of the arm, the 8th not entering the skin until below; in the other the 9th was seen to supply the skin of the arm and of the front of the forearm, while the 8th ran to the back of the forearm. The Minute Anatomy of the Brachial Plexus. 431 The lesser internal cutaneous is derived in all but very rare excep- tions from the 9th alone. In twenty cases it only once received from the 8th also. The posterior branches of the nerve roots unite to form the posterior cord. Hach of the four upper roots contributes to the cord, but the 9th rarely joins it. Out of forty-five cases where the point is noted, a fibre from the 9th occurs only six times, three times in foetal, three in adult cases. In one of these there was an unusually large root from the 10th nerve. In many adults the branch to the posterior cord can be seen to leave the 8th root before this is joined by the 9th. It may be taken then, as a rule, that the 9th does not contribute to the posterior cord. In the six exceptions the fibre from the 9th was invariably very small, and ran with the 8th, from which it was not isolated. The branches of the posterior cord are the three subscapulars, the circumflex, and the musculo-spiral. The first subscapular, which serves the subscapularis muscle, is often double, sometimes triple. It never receives from the 7th or 8th root, and is often wholly or partly given off from the 5th and 6th before they are joined by the 7th. Dissection shows that even when given off after the junction the 7th has still no share in it. This rule was invariable in forty-one cases. In twenty-three of these a dissection was made to see to which of the two upper roots the nerve was to be traced. It was found to come from the 5th in eleven cases, from the 6th in three, and from both in nine. I believe that owing to my not being sufficiently mindful that the muscle often receives more than one nerve, I have referred too large a number to the 5th alone. Whether this be so or no, it does not represent the whole supply given to it, for the lower part of the muscle always receives fibres from the second subscapular on its way to the teres major. This is a nerve of rather lower origin than the preceding. It was traced three times to the 5th, all foetal cases; thirteen times to the undivided 6th and Sth; four times to the 6th alone, one being an adult case; nine times to both 5th and 6th, seven being adult cases ; nine times to both 6th and 7th, seven being adult cases; and thrice it was formed by a branch from the cord of the upper two roots, and one from the 7th. This shows out of forty-one cases twelve in which the 7th contributed to the nerve, and twenty-nine in which it was excluded. There were only three in which the supply lay above the 6th, and thirteen where it lay wholly below the 5th. The question then arose—When the 7th enters the nerve, does it form part of the twigs which supply the subscapularis? I divided the nerve in three such cases, and found that in each the 7th went entirely to the teres major. The lower part of the subscapularis, however, is served, though not 432 Mr. W. P. Herringham. by the 7th, yet by a nerve which is of lower origin than the first subscapular. Thus in four instances, three of them adult, where the first subscapular came from the 5th alone, the second contained no oth, and in these cases the lower part of the muscle was supplied by a lower nerve. ‘This confirms also three other adult dissections of the first subscapular. In one it was triple; the first twig going to the upper fibres of the muscle ran from the Sth, the next to the middle fibres from the 5th and 6th, and the third from the 6th alone, below which came a twig from the second subscapular. In the two other cases the nerve was double, the upper twig coming from the 5th, the lower from the 6th root. The third subscapular going to the latissimus dorsi was traced in forty-two cases. Once it came from the 5th and 6th alone, three times it was formed by the 7th and a branch from the undivided 5th and 6th, four times by the 7th and a branch from the 6th (once with an addition from the 8th also), twenty-one times from the ws alone, and thirteen from both 7th and 8th. It is to be noted that in these three muscles there seems a regular progression from above downwards. The latissimus dorsi is usually served by a lower nerve than the teres, and this by a lower than the subscapularis, and though they are occasionally equalised their posi- tions in the series are never reversed. The circumflex nerve was shown in forty-three cases to be derived from the 5th and 6th alone. It never received a fibre from the 7th. In six cases, two of them adult, it came from the 5th alone, in twenty-two from both 5th and 6th, and in the remainder it was un- divided. It never arose from the 6th alone, and in many cases where both nerves helped to form it the branch from the 6th was so small that it could not be traced without breakage. I dissected the nerve three times. In all these the teres minor was supplied by the 5th only, and the deltoid by both 5th and 6th. The cutaneous branch was in one from the 5th alone, in the other two received a fibre from the 6th also. The musculo-spiral is formed sometimes by all fan of the upper roots, usually by the 6th, 7th, and 8th alone. Out of forty-six cases the 5th and 6th were undivided in twelve, in nine of the remaining thirty-four the 5th helped to form the nerve. Two of these were adult. In twenty-five, fourteen of which were adult, it was excluded. 3 In one adult case where the 5th entered the nerve it was found by dissection to run to the external cutaneous branch alone. The branch first given off is the nerve to the long head of the triceps, with which sometimes goes the internal cutaneous branch. The former was twelve times given from the 8th root, thrice from both 7th and 8th, and once from the 7th alone, The internal The Minute Anatomy of the Brachial Plexus. 433 cutaneous was seven times noted separately, in all of which it came from the 8th alone. That part of the muscle which arises below the musculo-spiral groove, commonly called the inner head, receives the ulnar collateral nerve on its inner part, and another branch which also serves the anconeus in its outer part. These two nerves were in six instances derived from the 8th only, in three from both 7th and Sth, in two from the 7th only, and in one from the 7th with the addition of a fibre from the 6th. In eleven cases where the supply of the outer head of the triceps was traced separately, it came from the 8th alone once only, from both 7th and 8th twice, from the 7th alone twice, from the 6th and 7th once, and from the 6th alone in five cases. In fourteen instances the nerves to the separate heads were not traced apart, but the whole muscle together with the internal cutaneous branch was in all supplied below the 6th. In three more the inner and outer heads were taken together, and in these also the supply was from the 7th and 8th. The 6th therefore only entered the triceps in five out of twenty- eight cases, and it is to be noted that in No. 19, the only case where the 6th entered the inner head, it wholly supplied the outer. The next branches given off are the two external cutaneous. The short branch was noticed in fourteen cases. Hight times it was shown to come from the 6th alone, once from both 5th and 6th, and in the remaining five from the first two roots, the 5th not being excluded. The long branch sprang from the 6th five times, in two of which the 5th was not excluded, from both 6th and 7th once, from the 7th thrice, from the 7th and 8th four times,* and from the 8th thrice. The nerve then supplies the brachialis anticus. The branch, or branches, going to this muscle, which are very small, were isolated eight times. ‘They were traced each time to the 6th, but in three cases the 5th was not excluded. The branch to the supinator longus was traced twenty-two times, always to the 6th, but in twelve cases the 5th was not excluded. The extensor carpi radialis longior was served twelve times by the 6th alone (in eight the 5th was not excluded), once by both the 6th and the lower nerves, and ten times by the lower part of the musculo- spiral, in four of which the 7th alone was traced to it, in five the 7th and 8th were not separated, and in one both were found supplying it. The brevior was supplied by the 6th six times, in four of which the 5th was not excluded, once by both the 6th and the lower nerves, and nine times by the lower nerves alone, in four of which the 7th was the agent, and in one both 7th and 8th. * Tn one case formed by the 7th and 8th the twig from the 7th ran nearer the radial border than that from the 8th. / 434 Mr. W. P. Herringham. The nerve to the supinator brevis was traced thirteen times, in every case to the 6th, but in five the 5th was not excluded. The two remaining divisions are the radial and the posterior in- terosseous. ‘The former was composed by the 6th alone thirteen times, in seven of which the 5th was not excluded, twelve times it was partly formed by the lower nerves. In all the seven cases when the two lower nerves had been divided the 7th alone was found to share in the radial. . I was able in only one case to dissect the radial consisting of both th and 7th. In it the 6th supplied the ball and dorsum of the thumb and the radial side of the index, while the 7th took the remainder. The posterior interosseous was in seven cases formed by the lower nerves entirely. In four it received also part of the upper nerves. The question arose whether the 8th ever entered the muscles of the forearm. Out of sixteen dissections, eleven foetal and five adult, twelve of which four were adult showed the 8th to cease before the forearm muscles were reached, four of which two were adult showed the 8th coming round to the back of the arm. In two of these latter the 7th and 8th formed equal parts of the posterior interosseous ; in the other two cases the 8th gave so minute a fibre to the nerve below the triceps that I could not trace it separately. In several of these cases the 5th was not excluded from the musculo-spiral, and must therefore be considered as a possible source of the supply, but it must be remembered that the probability of its taking part in the nerve is only, as before shown, nine in thirty-four, and that when dissected in the nerve it was found only to enter the short external cutaneous branch. These results show considerable variation in the distribution of the nerve roots, although I do not think it is greater than in any other of the structures of the body. But this variation is not extravagant. If a type be composed from the foregoing materials and compared with the varieties, it appears that if a muscle or a piece of skin is not supplied by the typical nerve, the place is filled only by one of its neighbours, not by a nerve far removed from it in the series. The teres major usually supplied by the 6th is on occasion supplied by the 5th, and sometimes by the 7th, never by the 8th or 9th. Again, some muscles seem to bear definite relations to each other, and their nerve supply seems also to vary solidly, so that the relative position of the muscles judged by their nerve supply does not alter although they be not served by the usual nerve. The best example- of this is in the three muscles which are attached along the inner side of the bicipital groove, the subscapularis, teres major, and latis- simus dorsi. The first is usually supplied by the 5th and 6th, the The Minute Anatomy oj the Brachiul Plexus. 435 second by the 6th, and the last by the 7th, and however much they vary above and below their typical place, they do not change their relations to each other. A similar relation exists between the two supinators and the two radial extensors. These last are sometimes supplied by the 6th, sometimes by the 7th, but they are never in any case placed above the supinators. These are always supplied by the 6th alone. The flexor group in the forearm show a similar fixed relation. ; From consideration of the usual regularity of the nerve supply, and of the limits within which alone it varies, I conclude that the nerve roots are not always composed of the same fibres, but that what is in one case the lower bundle of the 5th may be in another the upper of the 6th, and what is now the upper bundle of the 8th will at another time be the lower of the 7th root. This may be expressed as a law. LAW I.—Any given fibre may alter its position’ relative to the vertebral column, but will maintain its position relative to other fibres. It is to confirm laws that exceptions are important. One of my infants showed on both sides a larger root from the 10th or 2nd dorsal nerve than was usual. On the right side the nerve was slightly bigger than the natural, but on the left it was as large as the 9th, and this as large as the 8th, whereas the natural proportion of the 8th to the 9th is about 2 to 1, and the 10th root is a minute fibre only. On the right side the only abnormality in the plexus was that the 9th sent a branch to the musculo-spiral. But on the left the muscunlo-cutaneous received from the 7th, the median received no 6th, the teres major was supplied by the 7th alone, the circumflex received from the 7th, and the musculo-spiral was formed by the 7th, 8th, and 9th. In the ulnar both 8th and 9th entered the deep branch in the hand. Nevertheless the 4th sent a communication to the 5th, and the suprascapular and subscapular were given off normally. It appears that in this case the representation of the muscles in the spinal cord began at the ordinary level, but was more than usually lengthened out, its lowest point sinking so far that the 10th nerve conveyed an excessive proportion of fibres to the plexus. This unusual formation of the peripheral nerves still maintains the relative position of the muscles. I do not, however, find that every muscle comprised in the table holds. fixed relations with all others. There appear to be groups of muscles which are not intimately related. Thus the rise or fall of the three subscapular nerves does not entail a like movement in the nerves of the forearm. I have drawn up from my dissections the following table, giving the usual supply of the muscles of the upper limb. VOL. XLI. 26 436 Mr. W. P. Herringham. - Usual nerve supply. Muscles. ord, 4th, and oth Levator anguli scapule. oth. Rhomboids. 5th, or 5th and 6th. Supra-spinatus. Infra-spinatus. Teres minor. Sth and 6th. Subscapularis. Deltoid. Biceps. Brachialis anticus. 6th. Teres major. Pronator teres. Flexor carpi radialis. Supinator longus and. brevis. Superficial thenar muscles. Sth, 6th, and 7th. Serratus maguus. 6th or 7th. Hixtensores carpi radialis. 7th. Coraco-brachialis. Latissimus dorsi. Extensors at back of forearm. Outer head of triceps. 7th and 8th. Inner head of triceps. 7th, 8th, and 9th. Flexor sublimis. Flexor profundus, carpi ulnaris, longus panies, and pronator quadratus. 8th. Long head of triceps. : Hypothenar muscles. Interossei. Deep thenar muscles. | The pectoralis major receives from the 6th, 7th, 8th, and Yth; the minor from the 7th, 8th, and 9th. The question next arises upon what system are these muscles innervated? Is ita system of form or of function? Are muscles supplied by the same nerve because they act together or Dera they lie near one another ? In the first place the movements of the arm are so varied that there is hardly any combination of muscles unrepresented. In the com- monest and most necessary of all acts, that of putting a piece of food into the mouth, the food is grasped by the small muscles of the thumb and the interossei, the carpus is flexed upon the forearm, the forearm is half pronated and flexed upon the arm, and the pectoralis major draws the limb forward across the chest. Doubtless many other | muscles take an unrecognised share also. But of those here mentioned the anatomy of ordinary text-books shows that some, the flexors of the elbow, are served by the outer cord, the 5th, 6th, and 7th, whilst the interossei are supplied by the ulnar from the 8th and 9th. Ac- cording to my dissections that one action is brought about through every nerve in the plexus, and there is no action which does not involve several nerves at once. Looking at the theory from another point of view, is it trne that muscles which cause the same movement, or which continually con- The Minute Anatomy of the Brachial Pleaus. 437 tract together, are supplied by the same nerve? The action of the two pronators is indistinguishable, but the teres is supplied by the 6th, and the quadratus by the 8th and 9th; the thumb is always acting with the fingers, yet the superficial thenar muscles are served by the 6th, and the others by the 8th. It seems then certain that the place where functions are represented is higher than the peripheral nerves, and that these are distributed according to some other plan. The other system that suggests itself is the system according to place, and I find that the nerve supply of the muscles of the upper limb obeys three rules. LAW II.—A. Of two muscles, or of two parts of a muscle, that which is nearer the head-end of the body tends to be supplied by the higher, that which is nearer the tarl-end by the lower nerve. B. Of two muscles, that which 1s nearer the long aars of the body tends to be supplied by the higher, that which is nearer the periphery by the lower nerve. C. Of two muscles, that whichis nearer the surface tends to be supplied by the higher, that which is further from it by the lower nerve. The first rule has been already clearly exemplified in the supply of large flat muscles which receive more than one nerve, such as the pectoralis major and serratus magnus. The subscapularis is also an example. In ali these muscles it was shown that the upper parts were supplied by upper, the lower by relatively lower nerves. It remains to show how it is exemplified in the remainder of the muscles belonging to the limb. It has been laid down that in the first position of the foetus the great tuberosity and the external condyle of the humerus, the radius and the thumb are turned towards the head; the lesser tuberosity, the internal condyle, the ulna, and the little finger towards the tail. The first set of points have been called pre-axial, the latter post-axial. The muscles corresponding with the pre-axial points will be found to be supplied by higher nerves than those connected with post-axial points at the same level of the limb. Of the muscles which connect the scapula to the spine, the highest is the levator anguli scapule. This is supplied by the 3rd and 4th, and slightly by the 5th. Below this come the rhomboids supplied by the 5th alone. Of the muscles which join the humefus to the scapula those inserted into the outer or pre-axial tuberosity are supplied by the oth, with very slight, if any, aid from the 6th. Of those going to the post-axial part, the subscapularis, which is the highest, is supplied by the 5th and 6th; the teres major below it is supplied by the 6th, the latissimus dorsi which comes from lower down the body, and the 438 Mr. W. P. Hervingham. coraco-brachialis continuing down the post-axial border, are served by the 7th.* Of the muscles running to the upper end of the forearm, the biceps and brachialis anticus are supplied from the 5th and 6th; the triceps by the 7th and 8th, and it is remarkable that of the three heads of the triceps the outer, which is nearest to the pre-axial border, is am highest in the series. At this point the 5th ends. Of the muscles arising about the outer condyle, the highest in rank are the two supinators inserted into the radius, next the extensors of the carpus going to the radial side of the hand. Of those coming from the internal condyle, the two outermost, nearest, that is, to the radius, are supplied by the 6th. The innermost, the flexor carpi ulnaris, is supplied by the 8th and 9th (and at this point the 9th first begins to share in the system); the flexor sublimis, between the two, is supplied by the 7th and the lower nerves. None of the deep muscles are served by the 6th, and the 7th seldom runs to them. They are as a rule innervated by the lowest of the series. Passing to the hand, the superficial muscles on the outer side are supplied by the 6th, the superficial on the inner side by the 8th, the deep muscles being again supplied by the lowest of the nerves supply- ing the hand, namely, the 8th. It is remarkable and unexpected that the 8th and not the 9th should be the nerve going to the muscles of the hand. The explanation I would suggest is that the motor part of the 9th is rather an auxiliary nerve than an integral part of the plexus. The extremely small part which it often plays in the ulnar, and the fact that in two cases none of its fibres could be traced thither at all, confirm this view. The cutaneous supply of the limb exemplifies still more clearly the first of the rules laid down for the motor system. Over the deltoid runs the descending branch from the 3rd and 4th, below this comes the circumflex from the 5th, or from the 5th and 6th. The branch of the 5th in the musculo-cutaneous, and the short external cutaneous of the musculo-spiral given by the 6th, supply the skin over the outer condyle and head of the radius. Down to the end of the radius it is served by the musculo-cutaneous, either from the 6th alone, or as in one case by the 5th and 6th; the thumb is supplied by the 6th in the median and radial. On the inner side, the highest part, the skin of the axilla, is served by the 10th, the area below this by the junction of the 9th and 10th (the intercosto-humeral with the nerve of Wrisberg), next by the 9th * The deltoid, which would also exemplify the law, is omitted. I consider it uniform with the pectoralis major, not truly part of the long muscles of the limb. The Minute Anatomy of the Brachial Plexus. 439 in the internal cutaneous which rans down to the wrist. The little finger is supplied by the 9th in front, and by the 8th behind; the front of the three middle fingers by the 7th and 8th, the back by the 6th and 7th. | In the sensory system, therefore, as in the motor, the upper nerves can be traced down the pre-axial, and the lowest down the post-axial border; but a remarkable difference appears between the sensory and the motor system. Whereas in the latter it seemed the tendency for the lowest nerves to supply the lowest muscles, in the sensory nerves the extreme are nearest the upper, the middle nerves nearest the lower extremity of the limb. Thus, if the limb be seen from the front the two highest nerves on the outer and inner sides respectively are the 4th and the 10th. Lower than these the 5th and 6th take the outer, the 9th and 10th the inner side. Below the elbow the 6th alone takes the outer, and the 9th alone the inner. In the hand, while the 6th and 9th continue their positions, the 7th and 8th for the first time begin to join in the supply. Below the elbow a distinction begins to appear between the dorsal and palmar surfaces. Ifa line be drawn round the lower third of the forearm from the middle of the front surface to the radial border, across the dorsum, round the ulna, and so to the middle line again, it will cut in order cutaneous branches of the 6th, 7th, 8th, and 9th. Thus on the outer side behind the 6th in the musculo-cutaneous comes the musculo-spiral cutaneous from the 7th, and on the inner side behind the 9th in the internal cutaneous comes the dorsal cutaneous formed by the 8th. When the 8th was dissected in the internal cutaneous it was found going to the dorsum, and where the 7th and 8th joined to form the musculo-spiral branch the /th lay nearest of the two to the radial border. In the fingers, again, the 8th is the lowest nerve supplying the back. The 9th the lowest in front. The extremes therefore are on the palmar, the dorsal area occupies an intermediate position. Above the elbow the 8th in the internal cutaneous of the musculo-spiral, holding a position intermediate between the 10th in the intercosto-humeral, and the 5th and 6th in the circumflex, is an example of the same law. The sensory nerves therefore obey the following rules :— A. Of two spots on the skin that which is nearer the pre-axial border tends to be supplied by the higher nerve. B. Of two spots in the pre-axial area the lower tends to be supplied by the lower nerve, and of two spots in the post-amal area the lower tends to be supplied by the higher nerve. This, however unexpected, is not very difficult to understand. The 440 _ Mr. W. P. Herringham. epiblastic layer which forms the skin ensheaths the mesoblast, from which the deeper structures are developed. Suppose nerves, or what will afterwards become nerves, to be distributed to both. The meso- blast now begins to grow and pushes before it the enveloping sheath of epiblast. But, as may be seen with a piece of india-rubber, in any such process the points furthest from the centre of pressure remain nearest the top of the tube, and the point which was in the middle when the stretching began, will be at the furthest point of the sheath when itis finished. If in the arm the centre of pressure be supposed opposite to the area supplied by the 7th nerve, this nerve will always tend to supply the parts lying nearest the axis of the limb, and furthest from the axis of the body, while the 6th, 5th, and 4th in the pre-axial, and the 8th, 9th, and 10th in the post-axial area, will in that order approach the trunk. ‘This is the case. It appears then that in both sensory and motor systems the pre- axial area is supplied by higher nerves, the post-axial by lower; that the supply of the skin follows rules which obtain in any membrane subject to the same conditions, but that the supply of the muscles is modified by laws peculiar to themselves. This subject has not to my knowledge been before this investigated by human dissections. Ferrier’s* classification of the muscles by means of electric stimula- tion of the spinal roots in monkeys, though he explains the system as one of function, is not far removed from that now put forward. Forgue,f who stimulated not the spinal roots, but the branches which they gave to the nerves of the plexus, and who watched the contraction of dissected muscles, draws up the following lst for monkeys :— Median.t Bees ies Biceps. Brachialis anticus. Clavicular part of Médian | l deltoid. Pronator teres. Flexor carpi radialis. ° f Biceps slightly. Pronator teres. Flexor carpi radialis. externe. Méd; Pronator teres and flexor carpi radialis slightly. ae \e and 9 Flexor sublimis. Flexor profundus. Flexor interne. : : oaigle carpi ulnaris. Intrinsic muscles of hand. * + «Roy. Soc. Proc.,’ vol. 32, 1881, p. 12. + ‘Distribution des Racines Motrices dans les Muscles des Nise Emile Forgue. Montpellier, 1883. Page 45. t Forgue’s median is both median and musculo-cutaneous. Médian externe is the musculo-cutaneous and the outer head of the median, médian interne the inner head. NOTICES TO FELLOWS OF THE ROYAL SOCIETY. Applications and Reports to be considered at the May Meeting of the Government Grant Committee must be sent in by March 8lst. The Library is now open from 11 A.M. to 6 P.M., except on Saturdays, when it is closed at 1 P.M. A printed post-card of the papers to be read at each meeting will be sent weekly to any Fellow upon application to Messrs. Harrison and Sons, 46, St. Martin’s Lane, W.C. Ready. Royal 4to. pp. siv-326, cloth. Price 21s. OBSERVATIONS OF THE INTERNATIONAL POLAR EXPEDITIONS. 1882-1883. Fort Rak. With 32 Lithographic Folding Plates. Published and Sold by Triibner and Co. ge, k reduction of aaa on a single copy to Bellows of tho I R papa ‘Sold by Eyre and Spottiswoode. Price 20s. THE ROYAL SOCIETY. Surveys, Museums. SEconp Section :—General Science. _A Reduction of Price to Fellows of the Society. AND ALL BOOKSELLERS, PROCEEDINGS OF PEE ROYAL SOCTET ¥. VOL. XL. No. 250. —— ie ’ a > ai 7 } f £, gle ee a CONTENTS. \o S66 Say € Lo, RS Red kyl December 9, 1886. NG M6 ‘ “5 2 “SP G ot ff PAGE L. Note to a Paper on the Geometrical Construction of the Cell 6fthe-Honey Bee (‘Roy. Soc. Proc.,’ vol. 39, page 253). By Hmnry HENNEssY, F.R.S., Professor of Applied Mathematics in the Royal College of Science, Dublin . : j ‘ : : : : : d . 442 II. A New Method for the Quantitative Estimation of the Micro-organisms present in the Atmosphere. By Percy F. FRANKLAND, Ph.D., B.Sc., F.C.S,, F.1.C., Assoc. Roy. Sch. Mines. . : j d : ; 443 IM. Further Experiments on the Distribution of Miro Grea in Air (by Hesse’s method). By Percy F. Franxuanp, Ph.D., B.Sc., F.1.C,, F.C.S., and T. G. Hart, A.R.S.M. : : : d : . 446 IY. On the Intra-Ovarian Egg of. some Osseous Fishes. By ROBERT SCHARFF, Ph.D., B.Sc. . 3 : : f : : : Havin : . AAT VY. Note on a New Form of Direct Vision Spectroscope. By G. D. Liverne, M.A., F.R.S., Professor of Chemistry, and J. Dewar, M.A., F.RS., Jacksonian Professor of Natural Philosophy, University of Cambridge 449 December 16, 1886. I. Note on ite Inductive Solan os JOHN Hopxinson, M.A., D.Sc., F.RS. : ‘ : ‘ . 453 Addendum to the same. By Professor QuincKE, For. Mem. RS. . 458 IJ. On a Varying Cylindrical Lens. By Tempest ANDERSON, M.D., BSc. . 460 Iii. On the Action of the Excised Mammalian Heart. By Ava@ustus Water, M.D., and E. WaymoutH REID, M.B. . : } 5 . 461 For continuation of Contents see 4th page of Wrapper. Price Two Shillings and Sixpence. ak Part I, 1886. CONTENTS. I, A Memoir on the Theory of Mathematical Form. By A. B. Kemper, M.A., E.R.S. Ii. On Evaporation and Dissociation —Part I. By Professor Wr 1AM RAMSAY, Ph.D., and Sypnry Youne, D.Sc. / III. On Evaporation and Dissociation.—Part II. A Study of the Thermal Properties of Alcohol. By Wirttam Ramsay, Ph.D., and SypNney Youne, D.Sc. IV. On the Theory of Lubrication and its dpolicaee to Mr. Beauchamp Tower’s Experiments, including an Experimental Determination of the Viscosity of Olive Oil. By Professor OsBoRNE Reynoups, LL.D., F.BR.S. _Y. Further Observations on Enterochlorophyll and Allied Pigments. By C. A. MacMounn, M.A., M.D, VI. Researches on Myohematin and the Histohematins. By C. A. MacMounn, M.A., M.D. VII. An Experimental Investigation into the Form of the Wave-Surface of Quartz. By James C. McConnet, B.A. VIII. Description of Fossil Remains, including Foot-Bones, of Megalania prisca.— Part IV. By Sir Richsrp Owen, K.C.B., F.RS., &e. IX. Dynamo-Electric Machinery. By J. Hopkinson, M.A., D.8c., F.R.S., and E. Hopkinson, M.A., D.Sc. Index to Part I. Price £1 8s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. 4 Separate copies of Papers in the Philosophical Transactions, commencing with 1875, © may be had of Triibner and Co., 57, Ludgate Hill. ay te Ce eee Ee es ee The Minute Anatomy of the Brachial Plexus. 441 2 . “¥ Radial.* sand 6 eee from scapula. Supinator longus. Hxtensores carpi radiales. "i Latissimus dorsi. Teres major. Triceps. HExtensores carpi radiales. Extensors slightly. 8 and 9..Latissimus dorsi. Triceps. Extensors. Cubital.+ Flexor profundus. Flexor carpi ulnaris. Intrinsic muscles of hand. He lays down also the following laws :—f{ 1. Hach root furnishes branches to two systems, an anterior and a posterior. § 2. As the stimulus approaches the dorsal pairs, the contraction occurs in lower segments of the limb. 3. As the stimulus approaches the dorsal pairs, the contractions pass from the radial to the ulnar border. He also adds— “It is a secondary law that the superficial layers are supplied before the deep.” Both these observers worked with monkeys, and Forgue’s laws are, with the exception of the first, identical with those which human dissections have produced for me. That the details should exactly correspond is not to be expected in two different genera when indi- viduals of the same vary so widely. Electrical stimulation does not show the sensory supply. I have often tried to complete this account by dissecting the nerves upwards to the spinal cord. I have, however, never been able to rely on the results. The connective tissue permeating the nerve separates | and protects the bundles of nerve fibres composing it, and renders their dissociation impossible. But as the nerve nears the intervertebral foramen this tissue very rapidly diminishes, and in the foramen the root consists of nerve bundles with hardly any connective tissue between them. The nerve bundles in the adult might perhaps be separated even here from one another, but in the foetus, and these alone are for this purpose accessible to me, their minuteness and their _ softness have prevented any satisfactory dissection. * The radial here means the posterior cord of the plexus. + Ulnar. ft Pp. 41-43. . § This refers to the adult position. A truer view is to take the earliest observed position in the fcetus. ¥ 7 WoL; Xi. Y 8 442 On the Construction of the Cell of the Honey Bee. [Dec. 9, December 9, 1886. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The President announced that he had appointed as Vice- Presi- dents— The Treasurer. Dr. Archibald Geikie. Professor Bartholomew Price. Sir George Richards. The following Papers were read :— I. “ Note to a Paper on the Geometrical Construction of the Cell of the Honey Bee (‘Roy. Soc. Proc.,’ vol. 39, page 253).” By Henry Hennessy, F.R.S., Professor of Applied Mathematics in the Royal Cole. of Betence: Dublin. Received November 16, 1886. The result obtained in the paper on the cell of the honey bee, read November 26, 1855, by which the side of one of the lozenges composing the cell was found to be three times the difference between the two parallel edges forming the sides of one of the trapeziums of the prism, gives a very simple method for constructing the figure as follows. On a straight line take a part AD, and lay z 1836.] LHstimation of Micro-organisms in the Atmosphere. 443 off DC equal to twice AD, from D erect a perpendicular, and with radius AC = 3DA cut off DP; AC and AP are sides of the lozenge ACEP, which fulfils the required conditions. It is manifest that from this lozenge the remaining two lozenges and also the six trapeziums can be immediately constructed. The triangular pyramid which terminates the bee's cell may be in- scribed in a sphere whose diameter is three times the side of one of the edges of the pyramid. ‘The base of this pyramid is an equilateral triangle, the side of which is 1/3, and whose circumscribing circle has 2h for its diameter. This diameter is a chord of the spherical | segment whose versed sine is # Hence, if Dis the diameter of the sphere in which 2h is a chord, sD=h?+2?, but also h=2./22, and s=3u, whence | 415 | 9h We have also D = —— > 2h. ny 2/2 Hence the sphere contains within it all that part of the bee’s cell bounded by the three lozenges, together with as much of the hexa- gonal prism as may be measured by twice the side of a lozenge on the shorter edge of the prism. This result, together with the extremely simple mode now given for constructing the figure, divests the problem of the complexity and difficulty with which it was formerly sometimes regarded, and it may also possibly enable the naturalist to more readily azplain the action of the bees in moulding the cells of the honeycomb to their observed shapes. II. “A New Method for the Quantitative Estimation of the Micro-organisms present in the Atmosphere.” By PERcy He HP RANKLAND:, “Ph.D. B.Se., LC. F.C.S., Assoc. Roy. Sch. Mines. Communicated by Professor FRANKLAND, D.C.L., F.R.S. Received November 15, 1886. (Abstract. ) The author commences by giving a sketch of some of the more. important methods which have been devised for the bacterioscopic examination of air. In these he includes the experiments of Pasteur, who was the first to show that the air at different places varied in the number of micro-organisms which it contained, and of Tyndall, who proved that the microbes suspended in the air become rapidly deposited in the absence of any disturbing influence. He further 2H 2 444 Dr. P. F. Frankland. On the Estimation of — [Dee. 9, describes the process of Freudenreich and Miquel for the quantita- tive estimation of the bacteria in air, and points out the great advance which has been made upon their method in the adaptation by Koch, and later by Hesse, of a solid nourishing medium for their investiga- tion. In reviewing these different processes he draws attention to the advantages and disadvantages attending them, and proceeds to describe a new method which he has devised, and in which he has endeavoured to overcome some of the objections to which the others are open. The first experiments consisted in aspirating a definite volume of air through plugs of either glass-wool or sugared glass-wool, and mixing them by violent agitation with a definite volume of either broth or sterilised distilled water. A portion of this liquid was then added to gelatine-peptone, and plates were poured in the usual manner. In this way a much larger volume of air was capable of being examined than was possible hy Hesse’s method, whilst at the same time the solid medium, with its advantages, was retained. The experiments, however, show that although in many cases the results of two or more plates poured from the same mixture were fairly uniform, yet discrepancies did occur, and were sometimes very considerable, pointing to the fact that the organisms had not become evenly distributed throughout the liquid; also as only a portion of the air aspirated was capable of being examined, a very much larger volume of air had to be used in order to give a sensible result. This objection, which applies equally to Miquel’s method, which rests upon the assumption that it is possible to equally apportion out into a series of flasks or tubes the organisms contained in such a liquid, led the author to abandon the plate process, and to devise a method which should enable the whole volume of air aspirated to be examined. The method consists essentially in aspirating a known volume of air through a glass tube, containing two sterile plugs, consisting either of glass-wool alone, glass-wool and fine glass-powder, glass- wool coated with sugar, or sugared glass-wool and fine sugar-powder. The plugs are so arranged that the first one through which air is drawn is more pervious than the second. After a given volume of air has been aspirated, the two plugs are transferred respectively to two flasks, each containing melted sterile gelatine-peptone, and plugged with sterile cotton-wool stoppers. The plug is carefully agitated with the gelatine, so as to avoid any formation of froth, and when the plug has become completely disintegrated and mixed with the gelatine, the latter is congealed, so as to form an even film over the inner surface of the flask. On incubating these flasks at a tempe- | 1886.] ~ Miero-organisms in the Atmosphere, A45 rature of 22° C., in the course of four to five days the colonies derived from the organisms contained in the plugs make their appearance, and can be readily counted and further examined, A large number of experiments were made with a view of testing the accuracy of the process. For this purpose experiments were conducted, using sometimes single plugs, and sometimes double, and it was almost invariably found that all the organisms were deposited on the first plug, the second plug in the very exceptional cases when it did yield anything, containing rarely more than one organism. In connexion with Hesse’s method, it was found that in experiments performed in the open air, when a blank Hesse tube was exposed side by side with the one through which air was being aspirated, a number of organisms also became deposited in the blank tube, thus intro- ducing an important source of error in the quantitative results obtained by Hesse’s process. In the flask method, on the contrary, such blank tubes rarely contained any organisms, and in no case more _ than a vanishing proportion of those present in the other tube. _ This shows that whereas in Hesse’s apparatus any disturbance of the ' air during the experiment vitiates the accuracy of the result, in the flask method such disturbances are immaterial. On the other hand, in the absence of aérial currents, there was a remarkable concordance between the results obtained by Hesse’s method and by the ‘flask method.” This is important, not oniy as showing the quantitative accuracy of the new method, but by clearly demonstrating that the organisms present in the air exist in an isolated condition, and not in aggregates, as suggested by Hesse. It will be remembered that the plug is violently agitated with the gelatine- peptone, during which operation such aggregates would undoubtedly be broken up wholly, or, any rate, partially ; it would, therefore, be reasonable to expect that the ‘flask method” would yield a larger number, and possibly a far larger number of colonies than those - formed in Hesse’s tubes, but as, on the contrary, the numbers agree, under the circumstances described, in so remarkable a manner, it points to the fact that they exist in an isolated condition. The paper is illustrated with drawings and photographs. The following are the principal advantages which the author claims for the “ flask method.” 1. The process possesses all the well-known advantages attaching to the use of a solid medium. 2. The results, as tested by the comparison of parallel experiments, ean lay claim to a high degree of quantitative accuracy. 3. The results, as tested by control experiments, are not appre- ciably affected by aérial currents, which prove such a disturbing factor in the results obtained by some other methods. 4, The collection of an adequate sample of air occupies a very 446 The Distribution of Micro-organisms in Air. [Dee. 9, short space of time, so that a much larger volume of air can be con- veniently operated upon than is the case with Hesse’s method. Thus whilst the aspiration of 10 litres of air through Hesse’s apparatus takes about three-quarters of an hour, by the new method about 48 litres can be drawn through the tube in the same time, whilst a better plan is to take two tubes and alternately draw a definite volume of air through each, as by this means duplicate results are obtained. ) 5. As the whole plug, upon which the organisms from a given volume of air are deposited, is submitted to cultivation without sub- division, no error is introduced through the multiplication of results obtained from aliquot parts, and all the great difficulties attending equal subdivision are avoided. 6. The risk of aérial contamination in the process of flask-cultiwation is practically nil. 7. The apparatus required being very oe and highly portable, the method is admirably adapted for the performance of experiments at a distance from home, and in the absence of special laboratory appliances. Il]. “ Further Experiments on the Distribution of Micro- organisms in Air (by Hesse’s method).” By PrErcy F. FRANKLAND, Ph.D., B.Sc, F.C. F.C.8., andes ~A.R.S.M. Communicated by Professor FRANKLAND, D.C.L., F.R.S. Recerved November 22, 1886. (Abstract. ) The authors record a number of experiments, made with Hesse’s apparatus, on the prevalence of micro-organisms in the atmosphere. The results are intended to form a supplement to those already obtained by one of the authors, and published in the last volume of the Society’s ‘ Proceedings’ (vol. 40, p. 509). The greater number of the experiments have been performed on the roof of the Science Schools, South Kensington, the air of which has now been under observation at frequent intervals during the present year. The authors point out the variations according to season, which have taken place in the number of micro-organisms present in the air collected in the above place. The average results obtained were as follows :— ms — 1886.] . On the Intra-ovarian Egg of some Osseous Fishes. 447 Average number of micro-organisins found in 10 litres of air by 1886. Hesse’s method. AMI ose ae seit Sete a tte A, iar Ching e sae Day otal wots seas 26 MY ae eee sieco ee 8! pe cehe's as 6 31 RUC eerie ese alo are tay be oie oA Oily eo ie a yl tae aaieme sks 63 JUITATSS eg mi Sn ene See MOE Depbemlben. sans.” ya ase 43 Octoberce ses sce .s screen. 35 Experiments are also recorded showing the enormous increase in the number of micro-organisms present in the air of rooms consequent on crowding. In illustration of this point the authors cite a series of experiments made in the Library of the Royal Society during the evening of the conversazione in June last, on which occasion the following results were obtained :— Royal Society’s Number of micro-organisms Library. found in 10 litres of air. June 9, 1886. SOOM epee oe elon tieieis =e) 326 OP ras earls alba co ee ovine 4.32 June 10, 1886. SLC py) Betis ae hae hla site eer OO In addition to determining the number of organisms present in a given volume of air, the authors have also, in each case, roughly esti- mated the number falling on a given horizontal surface by exposing dishes filled with nutrient gelatine and of known superficial area, as in the experiments previously published. IV. “On the Intra-ovarian Egg of some Osseous Fishes.” By RoBeRT ScHARFF, Ph.D., B.Sc. Communicated by Professor McIntTosH, F'.R.S. Received November 17, 1886. (Abstract. ) _ These researches were carried out while acting as assistant to Professor McIntosh, at the St. Andrew’s Marine Laboratory. The chief material consisted of the intra-ovarian ovum of the gurnard (Trigla gurnardus). Many other marine forms, however, were examined. , The paper has been divided into the following five paragraphs : — 448 On the Intra-ovarian Egq of some Osseous Fishes. [Dee. 9, I. The Nucleus and its Changes in the Smaller Ova. In the smallest ova the nucleus occupies almost the whole of the interior, and the nucleoli are mostly attached to the inner surface of the nuclear wall. In somewhat larger eggs, the protoplasm sur- rounding the nucleus has increased, and is seen to be divided into a darker internal portion and a lighter external one. The ring of dark protoplasm becomes separated off from the nucleus in the later stages, and ultimately disappears. The dark protoplasm has no doubt origi- nated from the nucleus. The view that this has been caused by a substance being added from the nucleus is considerably strengthened by an observation made by Ransom, and published in the ‘ Philosophical Transactions,’ 1867, He found in fact that the germinal spots were soluble in some of the constituents of the yolk, At this stage the spots become vacuolate, and assume a variety of different forms, until the nucleus enters a new phase in the development of the intra- ovarian ege described in the following paragraph. II, The Larger Ova and the Formation of the Yolk Spherules, The egg has almost reached its final size, although far from being mature, when the nucleus is seen to have shrunk a little, and from it project protuberances on all sides. These protuberances or diverti- cula, most of which contain nucleolar particles, are ultimately con- stricted off from the nucleus, and travel towards the periphery of the egg. A similar transformation of the nuclear contents has recently been observed by Balbiani, Roule, and Fol, in invertebrate ova, and by Will, in amphibia. The buds with their enclosed contents form the yolk spherules, the solid mass in their interior soon breaking up into fine granules. Both Gegenbaur and Balfour speak in support of the view that yolk spherules originate within the egg. As the egg reaches maturity the nucleus degenerates still more, but I believe it never entirely disappears, _ Ill, The Egg Membranes. Much has been written on this subject, and it is still doubtful how many membranes exist. Almost all observers, however, agree that in the mature egg there is a membrane pierced by minute pores, which has generally been called “‘ zona radiata,” though other terms, such as vitelline membrane, egg-capsule, &c., have been applied to it, In the intra-ovarian egg of the gurnard I found a semi-fluid layer inside the zona, corresponding to the ‘‘helle Randschicht”’ described by Gegenbaur in the ova of birds and reptiles. It disappears in the ripe ovum. No membrane external to the zona, such as mentioned by various observers, was seen in this or other fish eggs. With regard to the pores in the zona radiata, it seems very probable 1886.) Ona New Form of Direct Vision Spectroscope, 449 that they are filled with processes from the follicular epithelium, and that the ege is nourished in this manner. In the ova I examined I could not see any processes, but they have been noticed by other observers in larger eggs of fishes, as well as of reptiles and mammals. IV. The Follicular Layer. The follicular layer in the mature ovum consists usually of a layer of closely-set cells, which, seen from above, have an hexagonal appear- ance, A peculiar modification of the follicular cells is found in the shanny’s egg (Blennius pholis). On one-half of the egg’s surface the cells are elongated, their depth gradually increasing towards a central point, In this way the depth of the cells varies from 0°007 mm. to 0°032 mm. I never noticed follicular cells passing through the zona radiata, as has been described by many authors. V. Development. No observation was made as to the origin of the egg, and it could not be determined whether the ovum originated from a simple trans- formation of an epithelial cell, or whether several unite, as in ‘“elasmobranchs.”” Jam inclined to the belief, however, that Brock’s and Kolessnikow’s views are correct, according to whom only one cell is concerned in the formation of the primitive egg. In small ova the follicular epithelium is composed of a few large cells. There are several possible ways in which the follicular layer might have origi- nated, either by an aggregation of epithelial cells round the ovum, as in elasmobranchs, or by a collection of connective tissue cells at the periphery of the ovum, or from the nucleus, as in many inverte- brates. I have not been able to come to any definite conclusion on this subject, The egg membranes appear after the follicle. The zona radiata is formed first, and, as well as the zonoid layer, it takes its origin from the yolk. VY. “Note on a New Form of Direct Vision Spectroscope.” By G. D. Liveine, M.A., F.R.S., Professor of Chemistry, and J. Dewar, M.A., F.R.S., Jacksonian Professor of Natural Philosophy, University of Cambridge. Received November 18, 1886, Direct vision spectroscopes are very useful in the observation of shifting objects, such as aurore and other meteors. They are generally in request for telescopic work, and also in all cases where rapidity of observation is of consequence, Ordinary direct vision 450 Messrs. G. D. Liveing and J. Dewar. [Dec. 9, spectroscopes with compound prisms have the disadvantage that the dispersion of the red end of the spectrum is small; less in proportion to that of the blue end than in spectroscopes with simple prisms. Also no measurements of lines can be made with them, except by means of a scale fixed in the field of view, which it is often difficult to see for want of illumination. | Some time since (‘ Roy. Soc. Proc.,’ vol. 28, p. 482) we brought under the notice of the Society a direct vision spectroscope on Thollon’s plan, which had not the faults of the instruments with compound prisms. It gave a dispersion equal to that of two prisms of 60°, and excellent definition, but the number of reflecting and refracting surfaces which had to be truly wrought was rather large, and the movement of the prisms by a screw made measurements with it slow. Since then we have tried a spectroscope with one of the Astro- nomer Rvyal’s half prisms, but we found it impossible to get good definition with the half prism for more than a small part of the visible spectrum; and in consequence faint bands near either end of the spectrum were quite invisible with this instrument. The arrangement we have’now to describe was intended to obviate the defects of the others. It has three prisms symmetrically arranged, the middle one serving both for refraction and reflexion. The course of a ray through the prisms is indicated in the annexed diagram. A ray lm in the line of the axis of the collimator meets the first prism ABC in m, is refracted at m and n, meets the second prism HGB at o, and is then refracted, undergoes two internal reflexions at p and q, and is refracted out at 7; it is then refracted through the third prism DEF at s and t, and emerges in the direction tu, which is a prolongation of its original direction Jm and coincides with the axis of the observing telescope. The prism EGB is fixed, the other two prisms are movable about axes parallel to their edges passing through the points m and t. They are rotated simultaneously in opposite directions by a pair. 1886.] Ona New Form of Direct Vision Spectroscope. 451 of linked levers, of which one carries a graduated arc of 94 inches radius, by which the angle of rotation can be determined. Those rays which suffer no deviation in passing through the train, must all follow a course through the fixed prism parallel to opgr, whatever their refrangibility ; but the angle of incidence at o will be different for the different values of the refractive index. By turning the two movable prisms into the positions shown by dotted lines the angle of incidence at o will be diminished, and a less refrangible ray will follow the course of no deviation. If then the first position of the prisms ABC, DFE, be that for which an extreme violet ray incident in the line lm suffers no deviation, all the less refrangible rays incident in the same direction may be successively brought to suffer no deviation by turn- ing the prisms towards the position shown by the dotted line. The angles of the prisms have, of course, to be adjusted so that the extreme violet ray may suffer no deviation. A simple calculation suffices for this when the refractive indices of the glass employed are known. We have had the fixed prism constructed with the acute angles about 333°, and the movable prisms with angles about 62°. With these angles, when the movable prisms are so placed that the angles of incidence at m and of emergence at o are equal (the position of minimum deviation), the ray which suffers no deviation is one somewhat more refrangible than K of the solar spectrum. When then the prisms are turned, less refrangible rays are successively brought into the field of view, but no ray much more refrangible than K can be brought into the field. By increasing the acute angles of the fixed prism, or by diminishing the angles of the movable prisms, a longer range can be given to the instrument, but at the expense of some dispersion. To prevent light passing directly from the collimator to the observing telescope, a stop HK is placed midway between the movable prisms. It will be observed that the fixed prism serves both as a reflector and refractor, the dispersion produced by it being the same as that of a simple refracting prism of 46° (or 186°—4EBG) in the position of minimum deviation. The dispersion for the extreme violet is there- fore that of two prisms of 62° and one of 46° in the position of minimum deviation. For less refrangible rays the position of the movable prisms is not that of minimum deviation and the dispersion is proportionally increased, so as to help, in a small degree, to correct the inequality of dispersion of the two ends of the spectrum. At the same time the symmetry of the arrangement is maintained for all rays when in mid-field, and sharp definition is secured for all parts of the spectrum. This isa most important character. We find that with our instrument A and H of the solar spectrum are equally well seen, and so are the red and violet lines of the flame spectrum of potassium. 452 On a New Form of Direct Vision Spectroscope. [Dec. 9, For greater convenience in manipulation, and at the same time to ensure a large angular aperture, our instrument has a short collimator and telescope. The magnification of the image is in consequence but small, but nevertheless it is easy to see the nickel line between the two D lines in the solar spectrum, and the large angular aperture makes it easier to see faint spectra from large objects, as well as to catch the light of a moving object. With an eyepiece of low power it serves well for the observation of absorption spectra. Measurements are made with it by bringing the line of which the position is to be measured to a fixed pointer in the middle of the field of view. The whole angle through which the prisms have to be moved in passing from A to H is 10° 15’, and as it is easy to read quarter minutes with the vernier, considerable accuracy of measure- ment may be attained. It must be observed, however, that the change of angle is not proportional to the change of refrangibility of the rays brought to mid-field, because a larger proportional rotation is required at the violet end, when the prisms are near the position of minimum deviation, than at the red end. Still there is a rotation of 33' 30” in passing from A to B, The prisms are enclosed in a box, and though this is an advantage in viewing faint spectra, it would sometimes he difficult to see the pointer without some means of illuminating either the pointer or the field. We effect the latter object by a slit in the side of the box, and a small white paper reflector, ab in the figure, which throws light from the opening in the box on to the side of the object glass, clear of the prism. The slit in the box may be closed with a shutter or with glasses of different colours. Lastly, the instrument can be used either with or without a stand. Without the stand it is light enough to be held in the hand and directed to the sky or to a moving object. It has been constructed for us by Mr. Hilger with his usual skill, 1886. ] On Specific Inductive Capacity. 453 December 16, 1886. Professor STOKES, D.C.L., President, in the Chair. ' The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— L “Note on Specific Inductive Capacity.” By JoHN HopkKINSoN, M.A., D.Sc., F.R.S. Received November 9, 1886. Consider a condenser formed of two parallel plates at distance z from each other, their area A being so great, or the distance:z so small, that the whole of the lines of force may be considered to be uniformly distributed perpendicular to the plates. The space between the plates is occupied by air, or by any insulating fluid. Let e be the charge of the condenser and V the difference of potential between the plates. If the dielectric be air, there is every reason to believe that V«e, that is, there is for air a constant of specific inductive capacity. My own experiments ({1880] ‘Phil. Trans,’ vol. 172, p. 355) show that in the case of flint-glass the ratio of V to e is sensibly constant over a range of values of V from 200 volts per em. to 50,000 volts per cm. From experiments in which the dielectric is one or other of a number of fluids and values of V upwards of 30,000 volts per cm. are used, Professor Quincke concludes (‘ Wiedemann, Annalen,’ vol. 28, 1886, p. 549) that the value of e/V is somewhat less for great electric forces than for small. From the experiments described in that paper, and from his previous experi- ments (‘ Wiedemann, Annalen,’ vol. 19, 1883, p. 705, e¢ seq.) he also concludes that the specific inductive capacity determined from the mechanical force resisting separation of the plates is 10 per cent. to 50 cent. greater than that determined by the actual charge of the condenser. The purpose of the present note is to examine the rela- tions of these important conclusions, making as few assumptions as possible. The potential difference V is a function of the charge e and distance #, and if the dielectric be given of nothing else. The work done in charging the condenser with charge e is Vde. If the “0 distance of the plates be changed to «+d, the work done in giving 454 Dr. J. Hopkinson. [Dec. 16, ik |g dV : the same charge is | (V+ 5, a de, hence the mechanical force re- 0 4 sisting separation of the plates is | Made. If the dielectric be air, Vv ra 2 A—=4re, and the attractive force between the plates is — or a AV? ment on the force between the plates when the potential difference is V and distance is 2, If K, be the dielectric constant as determined by an experi- ‘dV , /AV? K SS = —_———. e . . . . . . : J da j Sra? 1) If K be the dielectric constant obtained by direct comparisons of charge and potential, Axe . —— TC: (2) | ‘dV, [Ve . whence K,K= | e/a 2%) & lip) sae) sete We ordinarily assume that V« we; if so, K,/K=1. These results follow quite independently of any suppositions about the nature of electricity, about action at a distance, or tensions and pressures in the dielectric. Yet another method of determining the dielectric capacity of fluids has been used by Professor Quincke. Let a bubble of air be intro- duced between the two plates, let the area of the bubble be Aj, and let P be the excess of pressure in the bubble above that in the external air when the potential is V, allowance being first made for capillary action. The condenser now consists of two parts, one a fluid condenser area A— Aj, the other an air condenser area A,, we have mechanical work done in increasing the area of the bubble from A, to A,+dA,, with constant charge— but this work is wPdA,, “dV = | —de. whence x#P | aK, e v Now : Are = Ay, + (A—As) (V), 1886. | On Specific Inductive Capacity. 455 where 4re=Af(V), when the whole space is occupied by fluid, and the distance is @. The charge being constant we have— V A | z= 15 7f) \ dA,+ \oi+ (A— A,)f'(V) \ dV and for the purpose of transforming the integral hed 1s eek Gn) \ av, os A Tat? = {yv)-~ hav, Vv 1 Vv | whence azP =z) y— } ONY che Vetere a hy ee Gal eleus l f V T= {ims}. sien te ae Me ae Writing with Quincke K, for the dielectric constant determined by a measurement of P, we have by substituting in (4) f(V) = ae and © integrating as though K, were constant, 1 K,—1 V? ahr Aur Fo 8rra?P which may be taken as the definition of K,, 207 | f(V) whence Bae @ but from (5) we have, since in fact K = —) dP | ee = [a ee J | Sia a f(V)av ae | eB (fing te}, 456 Did; Hopkinson. [ Dec. 16, Hitherto we have made no assumption excepting that energy is not dissipated in a condenser by charge and discharge. We now make an oe concerning f(V), namely, that it is of the form ¢(V/z), 2 what a or in words, that the capacity of a condenser varies aw inversely as the distance between the plates. Then we have— 2 gk [ Dar} — 2K—K,. e e e « . e . . e e . (9) In words, the specific inductive capacity as determined by charge or discharge of a condenser at any given potential and distance between the plates is the arithmetic mean of the inductive capacity deter- tained by the force resisting separation of the plates and of that deter- mined by lateral pressure, the potential and distance being the same. This is true whatever be the relation between charge and potential difference, but it is at variance with the experimental result that K, and K, are both greater than K. Ry _ yy" 1 Thales Gp = |v (V)av /EV/(V). In the accompanying curve, let abscissa of any point P of the curve OQP represent V, ordinate f(V). If K,>K area ONPQO>area of triangle ONP, 1.e., unless the curve y = ( fx) has a point of inflexion between O and P, the fact that K,>K implies that K increases with V,—a conclusion again at variance with experimental results. We are thus unable to account for the observation on the hypo- thesis that the capacity varies inversely as x. Let us now suppose that f(V) = Vo(), that is to say, that however the capacity may depend on the distance, it is independent of the charge, or is constant for any 1886. ] On Specific Inductive Capacity. 457 given condenser. It at once follows that K,=K, which is discordant with observation. Consider, however, the ratio— ik ois 2 hl KK= | Zeenav [ati = 2, bey since 0= 9a) +Vo'@) when e is constant. Suppose ae =m, a positive constant quantity greater than unity— mop(x) tap (x) = 0, a™p(x) = C, a constant as regards a, or h(2) cc a-™, We could, therefore, account for K, being greater than K by sup- posing that the potential difference with given charge per unit of area does not vary as # but as #”, Such a supposition would be sub- versive of all accepted ideas of electrostatics. There remains one other consideration to be named. We have assumed throughout that the charge of the condenser depends only on the distance of the plates and their difference of potential, and is independent of previous charges or of the time the difference of poten- tial has existed. We have ignored residual charge. It is easy to see what its effect will be on determinations of K made by measuring the potential and charge of the condenser. It is not so obvious what its effect will be in all cases on the force between the plates. Consider a complete cycle of operations : the condenser is charged with quantity e, the distance between the plates is increased from x to ~+dz, the con- denser is discharged and the plates return to their initial position. The work done respectively in charging the condenser, separating the plates, and recovered in discharging the condenser, will depend on the rate at which these operations are performed. There are ideally two ways of performing them, so that no energy is dissipated by residual charge, first, under certain reservations, so rapidly that no residual charge is developed ; second, so slowly that at each potential the residual charge is fully developed ; in either case. the potential is a function of the then charge, and not of the antecedent charges. The attraction between the plates will differ according as the charge is an instantaneous one or has been long applied. If a liquid were found exhibiting a considerable slowly developed residual charge, the capacity determined by attraction with continuous charge would be greater than the capacity determined by an instantaneous discharge of the condenser through a galvanometer or into another condenser. VOL. XL, 21 458° Prof. Quincke. [Dec. 16, I am not aware that residual charge has been observed in any nie dielectric. Z The results shiva by Professor Qatdete are sce easy to recon- cile. For that reason it is the more desirable that their full signifi- cance should be ascertained. Full information is given of all the details of his experiments except on one point. It is not stated whether, in the experiments for determining K by direct discharge of the condenser, the capacity of the connexion and key was ascertained. It would in most ordinary arrangements of key be very appreciable in comparison with the capacity of the condenser itself. If neglected the effect would be to a certain extent to give too low a value of K, the effect being most marked when K is large. I have made a few preliminary experiments to determine K for colza oil with several different samples, and both with continuous charges and intermittent charges from an induction coil. The values. of K range from 2°95 to 3:11. Professor Quincke’s results in his first paper are K=2°443, Kya? 385, K,=3'296. The property of double rabiaettaned in liquids caused by electrifica-' tion is sometimes cited as showing that electrification is not propor- tional to electromotive force. The fact that the double refraction in: a liquid under powerful electromotive forces is very small would further show that there is a close approximation to proportionality, and that the deviation from proportionality would be insensible to any’ electrostatic test. Such conclusions, however, cannot be safely drawn in the case of bodies such as castor-oil, in which K+y?. In such bodies, assuming the electromagnetic theory of light, the yielding to electromotive force is much greater if the force be applied for such time as 10-* second than when applied for 107! second, and it is’ quite possible that the law of proportionality might be untrue in the’ former case, but very nearly or quite true in the latter. “Addendum to Dr. Hopkinson’s ‘ Note on Specific Inductive Capacity.” By Professor QUINCKE, For. Mem, R.S. Received December 5, 1886. Notiz tiber die Dielectricitatsconstante von Flissigkeiten, von G. Quincke. Bei Gelegenheit einer Untersuchung der Higenschaften dielectrischer Fliissigkeiten (‘ Wiedemann, Annalen,’ vol. 19, 1883, p. 707; vol. 28 1886, p. 529) hatte ich die Dielectricitatsconstante mit der electrischen Wage oder dem hydrostatisch gemessenen Druck einer Luftblase vrosser gefunden, als mit der Capacitaét eines Condensators, der von. Luft oder isolirender Fliissigkeit umgeben ist, und beim Umlegen eines Schliissels durch einen Multiplicator entladen wird. 1886.] On Specifie Inductive Capacity. 459 Die Capacitit des Schliissels und des kurzen diinnen Verbindungs- drahtes, welcher den Schliissel mit dem Condensator verband, wurde aber dabei als verschwindend klein vernachlassigt. . _In Folge einer brieflichen Mittheilung von Herrn Dr. John Hop- kinson habe ich in neuster Zeit die Capacitéat des Schliissels und des Zuleitungsdrahtes mit der Capacitét C des Condensators durch Multiplicator-Ausschlige bei derselben Potentialdifferenz der Beleg- ungen verglichen und dabei das Verhaliniss— = 01762 gefunden, also viel grésser als ich vermuthet hatte. ‘Zieht man von den heobachteten Multiplicator-Ausschlagen s, und S, fur den Condensator in Luft und in der dielectrischen Fliissigkeit den Ausschlag ab, der von der Electricitat auf dem Schliissel und Verbindungsdraht herrthrt, so erhalt man in der That durch das Verhaltniss der so corrigirten Ausschlige (s,) und (s;,) Werthe der Dielectricitatsconstante (K) der Flissigkeit, die fast genau mit den Messungen der electrischen Wage iibereinstimmen. Die Ueberein- stimmung ist so gross, wié bei der Verschiedenheit der benutzten Beobachtungsmethoden nur erwartet werden kann. So ergab sich z. B. Dielectricitatsconstante mit Multipl. Wagung. (K) P Aether .. sete 4,211 4,°394, Srlnveteliohlenstot, . an 2 °508 2 623 a Ss lial 2°640 2-541 BensGl TCs,» Maes MOS « hele. 2°359 2 °360 SS Eevee be ctai's- 3 schen& af iiobiw “eles cc pits 2°025 2:073 _ Heidelberg, December 1, 1886. [Note added Dec. 4th.—Professor Quincke’s explanation sets the questions I have raised at rest. There can be little doubt that K, K, and K, are sensibly equal and sensibly constant. The question what will happen to K, and K, if K is not constant has for the present a purely hypothetical interest.—J. H.] 25 2 460° On a Varying Cylindrical Lens. [Dec. 16, If. “On a Varying Cylindrical Lens.” By TEMPEST ANDERSON, M.D., B.Sc. Communicated by Professor A. W. WILLIAMSON, For. See R.S. Received November 18, 1886. A cylindrical lens of continuously varying power has long been a desideratum, and one was constructed and described by Professor Stokes, at page 10 of the Report of the British Association for 1849 (Transactions of the Sections). He points out that— “‘ Tf two plano-cylindrical lenses of equal radius, one concave and the other convex, be fixed, one in the lid and the other in the body of a small round wooden box, with a hole in the.top and bottom, so as to be as nearly as possible in contact, the lenses will neutralise each other when the axes of the surfaces are parallel; and by merely turning the lid round an astigmatic lens may be formed, of a power varying continuously from zero to twice the astigmatic power of either lens.” This very beautiful optical contrivance has the disadvantage that the refraction varies from zero in both directions at once, the refraction at any given position of the lenses being positive in one meridian, and negative or concave to an equal degree in a meridian at right angles to the first; moreover, there is no fixed axis in which the refraction is either zero or any other constant amount. It has in consequence never come into extensive use in the determination of the degree of astigmatism. The author has planned a cylindrical lens in which the axis remains constant in direction and amount of refraction, while the refraction in the meridian at right angles to this varies continuously. A cone may be regarded as a succession of cylinders of different diameters graduating into one another by exceedingly small steps, so _ so that if a short enough portion be considered, its curvature at any — point may be regarded as cylindrical. A lens with one side plane and the other ground on a conical tool is therefore a concave cylindrical lens varying in concavity at different parts according to the diameter of the cone at the corresponding part. Two such lenses mounted with axes parallel and with curvatures varying in opposite directions produce a compound cylindrical lens, whose refrac- tion in the direction of the axes is zero, and whose refraction in the meridian at right angles to this is at any point the sum of the refrac- tions of the two lenses. This sum is nearly constant for a con- siderable distance along the axis so long as the same position of the lenses is maintained. If the lenses be slid one over the other in the direction of their axes, this sum changes, and we have a varying cylindrical lens. The lens is graduated by marking on the frame the relative position of the lenses when cylindrical lenses of known power are neutralised. 1886.] On the Action of the Excised Mammalian Heart. 461 It was found by a practical optician to be impossible to wor _ glasses on a cone of large diameter, consequently a conical tool was ‘constructed with an angle of 45° at the apex, and 8 inches diameter at the base. A glass about 4 inches long was ground on the sides of this near the base, and as the resulting lens if ground on plane glass would have been too concave for most purposes, the outer side of the glass was previously ground to a convex cylindrical curve, and its axis applied parallel to the generating line of the cone in the plane of the axis of the cone. The result was concavo-convex cylinders of varying power suitable for the practical measurement of astigmatism. Lenses were exhibited varying from 0 to —6DCy, and from 0 to + 6DCy. III. “On the Action of the Excised Mammalian Heart.” By Aucustus WALLER, M.D., and E. WayMouTH REID, M.B. Communicated by Prof. BURDON SANDERSON, I’.R.8. Received November 18, 1886. (Abstract. ) The graphic method, the galvanometer, and the capillary electro- meter were made use of in this research. 'The animals used were the dog, rabbit, cat, rat, guinea-pig, and sheep. The chief results were as follows :— 1. Spontaneous ventricular contractions, complete and capable of being recorded, continue after excision of: the heart for periods which are variable, but which as arule are longer than has generally been received to be the case (Czermak and Piotrowsky). 2. Spontaneous ventricular contractions frequently outlast auricular contractions, both spontaneous and excited. 3. After spontaneous ventricular contractions have ceased to occur, electrical and mechanical excitations can still provoke contraction.. 4. The length of contraction of both auricle and ventricle of the excised heart is very great (15 to 20 times the normal duration), whether the contraction be spontaneous or excited. o. The length of the latent period increases with fe length of contraction ; it may be as long as 0°75 sec. 6. These nedewena (4 and 5) depend principally upon the sur- rounding temperature. 7. The heart (of a rabbit) can regain its excitability and its power of spontaneous contraction after it has been frozen hard. 462 On the Action of the Excised Mammalian Heart. - [Dece. 16, - 8. In an excited beat, in ventricle or auricle, of an excised heart, all parts are not in action simultaneously. 9. An excited contraction starts from the point excited—from ao base if the base is stimulated—from the apex if the apex is stimu- lated. 10. The excited contraction travels from its brs of origin, indif- ferently in any direction in the substance of the ventricle. 11. The rate of the wave of contraction measured by the graphic method varies, according to the temperature and state of the heart, from 3 to 85 cm. per second. 12. The velocity is (ceteris paribus) greater in the hearts of large than in the learts of small animals. 13. In spontaneous contractions of the ventricle the movement of the apex appears to precede that of the base. Note.—We have followed the wave of both spontaneous and pied contraction of the frog’s ventricle by the graphic method, and measured its rate. The rate is from 40 to 80 mm. per second. In spontaneous contraction, the movement of the base precedes that of the apex. 14. All parts of the uninjured heart are iso-electric; the Gere however, is often slightly negative to the base. 15. The electrical variation of spontaneous contraction 1s sometimes diphasic, (corresponding to the double variation of the beat of the frog’s heart), sometimes monophasic. 16. Electrical variations can be detected after visible contractions have ceased. 17. The direction of the electrical current follows no definite rule in our observations, negativity of apex preceding sometimes. negativity of base, at other times the reverse taking place. 18. The diphasie variation of excited contractions indicates that the part stimulated is first negative then positive to other parts. 19. Under conditions of lowered excitability a weak excitation will give a monophasic, a strong excitation a diphasic variation. 20. Towards the close of the period of excitability, the variation of the excited heat is single. It is less frequently single at the outset of experiment. 21. When excitatory variations can no longer be obtained, injury will produce a change of electrical state indicating negativity of tne part injured. 1886.] On the Reflexion of Light from Iceland Spar. “463 IV. “On the Effect of Polish on the Reflexion of Light from the Surface of Iceland Spar.” By C. Spurce, B.A., St. Catherine’s College, Cambridge. Communicated by R. T. GLAZEBROOK, M.A., F.R.S. Received November 18, 1886. | (Abstract. ) The most complete experiments which have been hitherto instituted to determine the optical effect of polishing the surface of a trans- parent body are those of Seebeck, described in ‘ Poggendorff, Annalen,’ vol. 20, 1830, p. 27; vol. 21, 1831, p. 290. Seebeck’s method was to quench, as far as possible, the reflected light with a Nicol, and to measure the angle of incidence. It was from a change in the angle of incidence, 7.e., the angle of polarisation, that an alteration of the state of the surface was inferred. ' This method is open to the objection that the light is not completely quenched, and, therefore, since the effect of polishing as observed by Seebeck was not very large, our conclusions as regards the surface state may be modified. Besides, the investigation is incomplete, for the precise change produced in the reflected light by polishing is not determined. The present paper, of which this is an abstract, is an account of experiments made to determine with greater accuracy the effect of polishing the surface of a crystal of Iceland spar, and also the exact alteration produced in the reflected light, 7.e., the change in the ratio of the axes of the ellipse, and in the azimuth of the major axis of the elliptically polarised light. To effect this, an elliptic analyser, pene of a Nicol aa a quarter undulation plate, was employed. If 17,7’ be the mean readings of moveable verniers attached to the Nicol in the two distinct positions in which the light is extinguished, and R, R’ similar readings of fixed verniers which determine the azimuth of the quarter plate, then tana, the ratio of the axes, and I, the azimuth of the major axis of the elliptically polarised light, were calculated from the formule— cos 24 = sin (r'—7r)/sin(R’—R) and IT = (R+R’)/2. Especial care was taken to secure fixity of position in all permanent parts of the instrnment, and in the setting of the face of the crystal, since a small change was to be detected. A first series of experiments was made with light reflected from a natural face, and with light reflected from the same face when polished. The polishing was performed by myself, and precautions 464 On the Reflexion of Light from Iceland Spar. [Dee. 16, were taken that the polishing was effected under exactly the same conditions. To ensure that the face was polished parallel to itself, the inelinations of the face to fixed faces were measured before and after polishing. The mean of about 400 readings was taken with each state of the face of the crystal, to obtain as accurate a result as possible. A second series of experiments was instituted with a view to determine the accuracy with which the means of each of the previous sets of observations could be determined. At the same time, a simple analyser, consisting of a Nicol and a graduated circle, was set up in addition to the elliptic analyser, with the object of testing the conclusions of Sir John Conroy as regards polished surfaces, which are given in the ‘ Proceedings of the Royal Society’ for February, 1886. The effect of rotation of the face of the crystal through a small angle in its own plane is also discussed. The observations are divided into sets, the means of which are compared with each other. Lastly, a set of experiments was made with a cleavage face split off near the former, and the results of these experiments were com- pared with those of the first ‘series made some fifteen months previously. The results of the experiments are embodied in tables, from which the following numerical results are extracted. I' in the case of the simple analyser corresponds to I for the elliptic analyser. The general conclusions of the paper are as fellows :— The process of polishing the surface of a crystal of Iceland spar with emery and rouge does most certainly alter the state of the surface. This alteration is evinced by a change both in the ratio of the axes and in the azimuth of the major axis of the elliptically polarised light. Such an alteration was observed in the case of two different crystals which were made the subject of experiment. The light reflected is shown to be exceedingly nearly plane polarised, so that the absolute amount of change in the ratio of the axes is small; but the relative change is considerable, for tan w is changed from 0°0334 to 0°0252. The change in the azimuth of the major axis is not very large. As regards disturbing causes, it is proved that moderate changes of temperature do not cause any very perceptible alteration in the surface state. The experiments prove a result unnoticed by Seebeck, that an emery-rouge polished surface gives perfectly concordant results on repolishing, and in this respect is quite as satisfactory as the chalk-polished surface that Seebeck recommends. And in general the results of the paper tend to confirm the views of Seebeck rather than those of Sir J. Conroy, for Seebeck in his paper prefers polished surfaces because of the liability of the natural surface to tarnish. 1886.] Contributions to the Chemistry of Chlorophyll. AG5 Elliptic analyser. Simple analyser. tan w. I. banis ihe Bed: ings. ings. Natural face. | 0 :03345| 108° 5-3’) 416 = == Ist Series.. eeese Same face polished ..|0°02517| 107 49°1 | 384 — — (Same face | polished ..|0°02655| 107 49°1 | 448 | 266° 5:3’| 100 Same face re- ou Baus polished ..|0-02723| 107 52-6 | 1280 | 265 57-3 | 500 (Elliptic analyser reset)..+s+e++ | Mho frst pol- ished face rotated \_ thro’ 4° 27’ | 0:08305| 107 39:2 960 — _ IIIrd Series. (Base of crystal Natural face. | 0-03368|108 31°4 | 384 — == broken up by cleavage)..... Polished face Dee. 8... — — — {111 15°7 40 Effect of time.. , BAihod ace Jan. 20°... — — Pe h6o Fe 60 Ais eae — — — |111 16-4 60 VY. “Contributions to the Chemistry of Chlorophyll. No. IL.” By EpwarbD ScHUNCK, F.R.S. Received November 29, 18386. (Abstract. ) In this paper the author continues his account of the properties of phyllocyanin, one of the products of the action of acids on chloro- phyll. He shows that by passing a current of CQO, through an alcoholic solution of phyllocyanin holding oxide of zinc in suspension, ‘a compound is obtained containing zinc and carbonic acid, a phyllo- cyanin zinc carbonate resembling phyllocyanin zinc acetate, but that no analogous compounds containing iron or copper are formed in this way. Attention is directed to the points of resemblance between the double compounds of phyllocyanin containing zine and chlorophyll itself, particularly as regards their susceptibility to change when exposed to the action of air and light, and it is shown that while 466 Mr. J.R.Green. Changes in the Proteids in the [Dec. 16, these compounds when in solution lose their colour almost as rapidly as chlorophyll itself, those containing copper are remarkably stable, since their solutions may be exposed for many weeks to light and air without undergoing any apparent change. The products derived from phyllocyanin by reduction are next described. The action of tin and hydrochloric acid on phyllocyanin passes through two distinct stages. During the first stage a colour- ing matter is formed which is remarkable from its solutions showing no less than eight absorption bands. The product formed during the next stage of the process is interesting from its yielding solutions of a bright red colour without any tinge of green, and from its resembling in some respects the colouring matters of red flowers. VI. “ On the Changes in the Proteids in the Seed which accom- pany Germination.”. By J. KR. “GREEN Ses Demonstrator of Physiology in the University of Cam- bridge. Communicated by Professor M. FostEr, Sec. R.S. Received November 25. (Abstract.) The processes of the germination of the seed have been in recent years investigated by v. Gorup-Besanez, who in a series of papers written in 1874 and 1875,* has stated that the changes in the reserve proteid materials are probably due to the action of a proteolytic ferment, as from the seeds of the vetch, hemp, flax, and barley plants he was able to extract a body which converted fibrin into peptone. Later, in 1878, Krauchf disputed v. Gorup-Besanez’s conclusions, and claimed. that his results were erroneous on account of imperfect methods of working. As v. Gorup-Besanez based his statement partly on the detection of peptone by the biuret test after the digestion had gone on for some time, and partly on a diminution of the fibrin, Krauch explained his results by saying that the digestive extract itself gave a biuret reaction, and that the diminution of the fibrin was only due to a shrinkage of its flocks. i During the past year I have been carrying out a series of experiments bearing upon this disputed point, and have succeeded in demonstrating in the seeds of the lupin (Lupinus hirsutus) the existence of such a ferment as v. Gorup-Besanez stated to be present, and in ascertaining some particulars as to its condition in the resting seed, the nature and conditions of its action, and the changes which * “Deutsch. Chem. Gesell. Ber.,’ 1874, p. 1478. Ibid., 1875. + “ Beitrage zur Kenntniss der ungéeformten Penwaniee in den eeaneemy ‘ Land- wirthsch. Versuchs-Stat.,’ vol. 27, 1878, p. 383. 1886.] = Seed which accompany Germination. 467 it brings about not only in the course of its action on fibrin, but also on the aleurone or proteid reserve material in the seed itself. The method which I used in the investigation was somewhat different from that of v. Gorup-Besanez. As Krauch claimed that the biuret reaction obtained was due to some proteid in the digestive extract used, and as the vegetable peptones found in the seed of the lupin do not dialyse, while true peptone does so readily, I carried on -my digestions always in carefully tested tubes of dialysing paper, so that the fluid outside the latter might enable me to see if peptone were really formed or no. Seeds of Lupinus were germinated for about a week, till they had protruded a radicle of about 14 inch in length; they then gave an acid reaction to litmus-paper. They were divested of their coats, the radicles removed, and the cotyledons ground. The resulting powder was extracted with glycerine, and the extract dialysed till no trace of any crystalline bodies that had been formed during the germination could be detected in the dialysate. No trace of peptone or other body giving a biuret reaction passed the dialyser, even after a week’s exposure. The extract was then acidified with HCl to the extent of 02 per cent., put into a fresh dialyser, some swollen-up boiled fibrin added, and the dialyser put into a beaker and surrounded with 02 per cent. HCl. It was then left at a temperature of 40° C. Control experiments, some with boiled digestive extract, some with 0°2 per cent. HCl only, were carried out side by side with the others. The process of digestion was very slow, the time taken up being very much more prolonged than is the case with the gastric or pancreatic ferments. After some time, however, the dialysate in the -beaker containing the tube in which the unboiled extract of the cotyledons had been placed gave a very marked biuret reaction, and after concentration it deposited crystals of leucin. The other dia- lysates contained no peptone or crystalline body. I repeated the experiments many times with varying quantities of the extract of the cotyledons and with varying amounts of fibrin, -and in all cases I was able to see that a proteolytic ferment was present in the germinating seed, and that it formed not only peptone but leucin, behaving like pancreatic rather than gastric juice. In this latter particular I am somewhat at variance with v. Gorup-Besanez, who says he was not able to see that the decomposition of the fibrin proceeded beyond the stage of peptone. Further investigations into the condition of the action of the ferment showed that it worked best in a medium acidified to the extent of 0°2 per cent. HCl: that the temperature most favourable for its working was 37—40° C., that its activity was.somewhat impeded by the presence of excess of neutral salts, and that it was speedily destroyed by contact with alkalis, even to the extent of 1 per cent. 468 Changes in the Seed accompanying Germination: [Dec. 16, In the resting seed the ferment exists in the form of a zymogen, as is the case with those of the stomach and other digestive organs. This is, however, very readily converted into the active ferment by contact with dilute acids. The point was somewhat difficult of proof, but was ascertained by a modification of the method adopted by Langley and Hdkins* in their work on the condition of the ferment in the gastric glands. From this paper it appears that while both alkalis and CO, destroy both the ferment and the zymogen, the latter is much more easily affected by CO, than the former. I found this to be the case with the extracts of the seeds. After a stream of CO, had been passed through them, treatment with acid failed to make them active, though the acid soon developed ferment-power in extracts not treated with the gas. The reaction of the resting seeds was neutral. The proteids existing in the seeds of Lupinus have been ascertained by Vines+ to consist of hemialbumose and globulin. I prepared from a quantity of the resting seeds a considerable bulk of these by the methods Vines describes, and submitted ‘them in a state of fair purity to the action of the ferment. The outcome of a long series of experi- ments so carried out was that the proteids of the seeds were changed by the ferment in much the same way as fibrin. There was soon a quantity of parapeptone formed, which was soluble readily in weak acids or alkalis. This was followed or accompanied by the appear- ance of peptone, and later, leucin and asparagin were formed. The latter bodies were obtained in-some.quantity by the method described by v. Gorup-Besanezt for the separation of leucin from other bodies in the fluids in which it is found. This course of digestion of the seed proteids was corifneadead by examination of the seeds at different stages in their natural germina- tion. In those which were just starting, parapeptone in quantity was present in the germinating cotyledons; a little later abundance of peptone was found. In no case was peptone found in the radicles, but from these plenty of asparagin was easily obtainable. Besides the biuret test for the peptone a more delicate one was generally used, which has been described by many writers. It consists in freeing the solution from all other proteids by boiling with freshly prepared ferric acetate and then adding to it acetic acid and phosphotungstate of soda. Peptone is then precipitated. The conclusions which seem to follow from the whole course of the experiments are :— 1. There exists in the seed of the lupin when germinating a proteo- * © Journal of Physiology,’ vol. 7, p. 371 (1886). + ‘ Journal of Physiology,’ vol. 3, p. 93 (1881). t ‘ Anlcitung zur qualitativen und quantitativen Zoochemischen Analyse.’ 1886.] Eclipse of the Sun in 1886 observed at Grenada. 469. lytic ferment which will convert fibrin into peptone and then into leucin and tyrosin. 2. This exists in the resting seed in the form a zymogen, which is easily convertible into the ferment. ' 3. The ferment acts best in a slightly acid medium; its activity is hindered by neutral salts and destroyed by alkalis, and it is most active at a temperature of 40° C. 4. The process of germination is started or accompanied by a trans- formation of the zymogen into ferment on the absorption of water and the development of vegetable acids in the cells of the seed. 5. The ferment so developed converts the proteids of the resting seed into acid albumin or parapeptone, peptone, and crystalline amides, 6. The nitrogen travels from the cells of the seed to the growing points in the form of the latter bodies and not in that of peptone or other proteid. VII. “Preliminary Account of the Observations of the Eclipse of the Sun at Grenada in August, 1886.” By Captain Darwin, R.E. Communicated by LorD RAYLEIGH, Sec. R.S. Received November 25, 1886. The instruments allotted to me consisted of the coronagraph and the prismatic camera; the two instruments being mounted on the same equatorial stand. The prismatic camera is the same instrument which was used at the eclipses of 1882 and 1884. It consists of an ordinary photo- graphic camera with a 60° prism placed in front of the lens. The coronagraph consists of a reflecting telescope arranged for obtaining photographic records, and in which special precautions are taken to avoid internally reflected light. ; This instrument was designed by Dr. Huggins, with the idea that it might be possible to obtain photographs of the corona in sunlight, that is at other times than at eclipses, and I was especially directed to test the practicability of this method, The test could be applied in two ways :— lst. By obtaining photographs shortly before or after the eclipse, and comparing any irregularity that might appear in the halo round the sun with any photographs of the corona taken during totality; a similarity of form indicating that the corona had been photographed. 2nd. To take photographs during partial eclipse. Then if the light of the corona produces any effect on the plate, the limb of the moon should be visible against it, —z 470 Eclipse of ‘the Sun in 1886 observed at Grenada. oi Dee: 16, ‘On the day before the eclipse I took a considerable number of photographs for the first test. No similarity has yet been traced between the form of the corona as obtained on these plates, and the form of the true corona as obtained during the total eclipse. During totality I had intended to carry out the following pro- gramme :—During the first minute a photograph was to be taken with the prismatic camera. After that four plates were to be exposed with the coronagraph with the same length of exposure as that given during sunlight. The exposure was given automatically by means of a shutter, with an estimated length of between one-tenth and one-fifth of a second. Besides these, two photographs were to be — with exposures of five and ten seconds respectively. | The programme could not be carried out exactly. Immediately after I had commenced exposing the prismatic camera, 1 looked up, and found that the corona was covered by a light cloud. The sky became clear again in about fifty seconds. I was anxious not to take any other photographs at the same time for fear of vibration ; but as nearly a minute had been lost something had to be sacrificed, and I decided to take some-of the photographs with the coronagraph before putting the cap on the prismatic camera. I do not think that the work has suffered in consequence, and at all events I obtained all the plates I had intended to. As to the results, I am not yetin a ponies to fully report on them. The photograph obtained with the prismatic camera shows several images of the prominences, and it therefore gives every promise of yielding good results when measured and examined. The five and ten second photographs of the corona show signs of a slight vibration, but they will be useful for the inner part of the corona. As my main object was to obtain instantaneous photographs, these long exposure plates had to be obtained by working the auto- matic shutter by hand; it was this probably that caused the vibration. The instantaneous photographs of the corona when developed were complete blanks, proving that the exposure was too short. It should, however, be observed that this does not prove that the light of the. corona was insufficient to cause an appreciable effect on the plate if combined with other light. More lght energy is necessary to start photographic action than is required to produce a visible difference of shade when once the action is started. ~ Many of the photographs taken during partial eclipse show what may be described as a false corona, that is, an increase of density near the sun and between the cusps, or in front of the moon. In none of them can the moon be seen eclipsing the corona. The results, therefore, are adverse to the possibility of obtaining photographs of the corona in sunlight; it is, however, I consider by no means proved that the method is impossible. But at present I am 1886.] Presents. 471 inclined to consider that the result tends to show that a practical method of obtaining photographic records of the corona during sun- light is not likely to be obtained. The trial was not conclusive because the conditions were very unfavourable. In order to reduce the air-glare to a minimum, so that the light of the corona shall not be overpowered, the following points must be observed :— - Ist. The air should be clear and dry. . 2nd. The sun should be near the zenith. . 8rd. The station should be at a considerable SA above the sea. Ath. The corona, if it does ey in intensity, should be at its maximum brightness. Now every one of these conditions was unfavourable. The air was saturated with moisture, the sky was of a hazy blue, the sun was low, the station was near the sea-level, and the corona according to the general impression was not so bright as on other occasions. I hope, however, to deal more fully with the considerations on another occasion. The Society adjourned over the Christmas Recess to Thursday, January 6th, 1887. Presents, December 9, 1886. Transactions. Baltimore :—Johns Hopkins University. Studies from the Bio- logical Laboratory. Vol. III. No.8. 8vo. Baltimore 1886. The University. Cambridge, Mass. :—Harvard College. Bulletin of the Museum of Comparative Zoology. Vol, XII. No. 6. 8vo. Cambridge ESSey": The Museum. Harvard University. Bulletin. Vol. IV. No. 6. 8vo. 1886. : The University. Frankfort :—Naturforschende Gesellschaft. Abhandlungen. Band XIV. Heft 1. 4to. Frankfurt 1886. The Society. _ Leipzig :—K6nigl. Sachs. Gesellschaft der Wissenschaften. Ab- handlungen. Band XIII. Nos. 6-7. 8vo. Leipzig 1886. The Society. . 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The Institute. 2x 2 A478 Presents. [ Dee.#46, Transactions (continued). Trondhjem :—Kong. Norske Videnskabers Selskab. Skrifter. 1882. Svo. Throndhjem 1883. The Society. Upsala :—Kongl. Vetenskaps Societet. Nova Acta. Series 3. Vol. XIII. Fasc. 1. 4to. Upsalice 1886 The Society. Universitet. Arsskrift. 1885. 8vo, Upsala [1886]. The University. Vienna :—Anthropologische Gesellschaft. Mittheilungen. Band XV. Heft 3. 4to. Wien 1885. The Society. K. K. Geographische Gesellschaft. Mittheilungen. 1885. 8vo. Wien 1885. The Society. K. K. Naturhistorisches Hofmuseum. Annalen. Band I. Heft 2. 8vo. Wren 1886. The Museum. K. K. Zoologisch-botanische Gesellschaft. Verhandlungen. Band XXXVI. Hefte 1-2. 8vo. Wien 1886. The Society. Warwick :—Warwickshire Field Club. Proceedings. 1885. 8vo. Warwick 1885. The Club. Washington :—Smithsonian Institution. Report. 1884. 8vo. Wash- ington 1885. The Institution. Watford :—Hertfordshire Natural History Society. Transactions. Vol. IV. Parts 1-3. 8vo. 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London 1884. The Observatory. Cordoba :—Observatorio Nacional. Argentino. Resultados. Vol. XIV. Catalogo General. 4to. Cérdoba 1886. The Director. 1886.] Presents. 479 Observations, &e. (continued). London :—Greenwich Observatory. Results of the Astronomical Observations, made 1884. 4to; Spectroscopic and Photographic Results, 1884. 4to; Magnetical and Meteorological Observa- tions, 1884. 4to; Observations, made 1884. 4to. London 1886. The Observatory. Meteorological Office. Monthly Weather Report. February to June, 1886. 4to; Weekly Weather Report. Vol. JII. Nos. 16- 41. 4to. 1886. Ditto, Quarterly Summary. Vol. III. Ap- pendix 1. January to March, 1886. 4to; Quarterly Weather Report. January to March, 1878. 4to. 1886; Hourly Read- ings, 1884, January to March. 4to. London 1886. The Office. Vienna :—K. Akad. der Wissenschaften ; Die Internationale Polar- forschung 1882-83. Osterreichische Expedition auf Jan Mayen. Band II. Abth.1; Band III. 4to. 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Wiirzburg 1885. The Author. Kops (Jan) Flora Batava. Afi. 273-274. 4to. Leiden [1886]. The Netherlands Legation. Kronecker (L.), For. Mem. R.S. Uber einige Anwendungen der Modulsysteme. 4to. Berlin [1886]; Hin Satz tber Discrimi- nanten-Formen. 4to. Berlin [1886]. With seven Excerpts from the Sitzungsberichte d. K. Preuss. Akad. d. Wissen. zu Berlin, by the same author. Prof. Kronecker. Javersidge (Prof.), F.R.S. Address delivered to Royal Society of N.S.W., May, 1886. 8vo. Sydney 1886. The Author. Malton (Louis) Quadrature du Cercle déterminée. [Three copies. } Svo. Paris 1886. The Author. Moore (¥.) The Lepidoptera of Ceylon. Part XII. 4to. London 1886. Government of Ceylon. Morland (Sir Samuel) The Poor Man’s Dyal. Sm. 4to. 1689. Re- print. Mr. R. B. Prosser. Parker (R. W.) Congenital Club-foot. 8vo. London 1886. The Author. Phipson (Dr. T. L.) Outlines of a new Atomic Theory. 4to. London 1836. The Author. Poujade (P.-R.) Notes 4 propos du Choléra. 8vo. Montauban 1886. The Author. 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Applications and Reports to be considered at the May Meeting of the Government Grant Committee must be sent in by March 31st. The Library is now open from 11 A.M. to 6 P.M., except on Saturdays, when it is closed at 1 P.M. A printed. post-card of the papers to be read at each meeting will be sent weekly to any Fellow upon application to Messrs. Harrison and Sons, 46, St. Martin’s Lane, W.C. Ready. Royal 4to. pp. xiv-326, cloth. Price 21s. OBSERVATIONS OF THE INTERNATIONAL POLAR EXPEDITIONS. 1882-1883. Fort Bar. With 32 Lithographic Folding Plates. Published and Sold by Tritbner and Co, CONTENTS (continued). PAGE TV. On the Effect of Polish on the Reflexion of Light from the Surface of Iceland Spar. By C. Spuras, B.A., St. Catherine’s College, Cambridge 463 V. Contributions to the Says of heer: No. II. By Epwarp ScHunck, F.R.S. . : : : ’ : . 465 VI. On the Changes in the Proteids in the Seed which accompany Germination. By J. R. 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MARTIN’S LANE, W.C., AND ALL BOOKSELLERS. far ase bate nadie al i iad Anaaaiitte il Qe rer pict! d bi val | le a, ener / OBITUARY NOTICE OF FELLOW DECEASED. James Apsoun, M.D., was Professor of Chemistry in the University of Dublin from 1850 to 1875. He died on the 2nd of June, 1886, at Southill, Blackrock, co. Dublin, in his 91st year. Dr. Apjohn was born at Sunville, co. Limerick, on the lst of September, 1796, and, having received his elementary education at the Tipperary Grammar School, he entered Dublin University in 1814. After a distinguished undergraduate course, he took his Arts degree in 1817, and in 1821 obtained the M.B. Sixteen years later he proceeded to the M.D. degree. Apjohn’s love for experimental science seems to have been kindled during his medical studies, and after graduating he devoted himself almost exclusively to the pursuit of chemistry and physics. About 1824 several eminent physicians and surgeons—including Groves, Marsh, Jacob, and Cusack—decided to establish a new medical school at Parke Street, in Dublin, and in the following year Apjohn joined the staff of the new school as lecturer in chemistry. Here he acquired considerable reputation as a lecturer, and three years later he was transferred to the newly-established Chair of Chemistry in the College of Surgeons’ School, which he held until 1850, when he was appointed to the University Chair of Che- mistry on the death of Dr. Francis Barker. Apjohn’s official con- nexion with the University began, however, in 1841. About that time the Board of Trinity College founded an Hngineering School, and appointed Apjohn to the Chair of Applied Chemistry and Mineralogy—an office which he continued to hold when he succeeded Barker in 1850. On Dr. Apjohn’s retirement from professorial work, Mineralogy was transferred to the Chair of Geology in the University, and Applied Chemistry was permanently attached to the Chair of Chemistry. The principal sciéntific work of Dr. Apjohn was rather physical than chemical. The general study of hygrometry had a special — attraction for him, and of the forty-nine scientific papers named in the Royal Society’s Catalogue, a large proportion relates to that subject. — In the course of his work on the theory of the wet bulb hygrometer, he arrived at the expression well known as “ Apjohn’s Formula” for ascertaining the dew point. The study of hygrometry led to much interesting work on the specific heat of gases, and in 1837 Apjohn received the Cunningham Medal from the Irish Academy for his paper ‘“‘ Upon a New Method of Investigating the Specific Heats of the Gases.”” The method con- sisted in noting the fall in temperature sutfered by the wet bulb thermometer when immersed in the perfectly dry gas, whose specific VOL. XLI. b iT : heat was required. From 1838 onwards Dr. Apjohn devoted less attention to physical work than to mineralogical chemistry, He was a frequent contributor to the literature of the latter subject. In 1838 he analysed and described a mineral from Algoa Bay, South Africa, which proved to be a somewhat efloresced manganese alum, which has since been named ‘ Apjohnite.” In 1840 he described a mineral found at Kilbricken, co. Clare, which is closely related to | geocronite, but is non-arsenical. Again, in 1852 he was concerned in the description, under the name of “Jellettite,” of a yellowish-green garnet found near Zermatt, Monte Rosa, by Dr. Jellett, the present Provost of Trinity College. Papers on the relations of pyrope, of pennine, and on Mexican hyalite are also to be found amongst his contributions to mineralogy. Dr. Apjohn contributed to the ‘“‘ Cyclopeedia of Practical Medicine” the articles on electricity, galvanism, toxicology, and spontaneous combustion, and it is stated that the latter article supplied Dickens with the facts on which he founded his account of Krook’s death in ‘** Bleak House.” As the representative of the University of Dublin in the General Medical Council, Dr. Apjohn took a prominent part in the production of the ‘‘ British Pharmacopceia.”” Almost every chemical process and test described in the first edition of the ‘‘ Pharmacopceia”’ was care- fully examined in the Trinity College Laboratory, and much of the success of the work was due to Apjohn’s laborious revision in detail. He was elected to the Fellowship of the Royal Society in 1853; he was a Vice-President of the Royal Irish Academy; and at the time of his death was second on the roll of Fellows of the King and Queen’s College of Physicians. Dr. Apjohn was widely esteemed throughout his long life as a thorough and earnest worker, a singularly lucid and able lecturer, and an upright and honourable man. : J, Hie dike OBITUARY NOTICES OF FELLOWS DECEASED. James Apsoun, M.D., was Professor of Chemistry in the University of Dublin from 1850 to 1875. He died on the 2nd of June, 1886, at Southill, Blackrock, co. Dublin, in his 91st year. Dr. Apjohn was born at Sunville, co. Limerick, on the lst of September, 1796, and, » having received his elementary education at the Tipperary Grammar School, he entered Dublin University in 1814. After a distinguished undergraduate course, he took his Arts degree in 1817, and in 1821 obtained the M.B. Sixteen years later he proceeded to the M.D. degree. Apjohn’s love for experimental science seems to have been kindled during his medical studies, and after graduating he devoted himself almost exclusively to the pursuit of chemistry and physics. About 1824 several eminent physicians and surgeons—including Groves, Marsh, Jacob, and Cusack—decided to establish a new medical school at Parke Street, in Dublin, and in the following year Apjohn joined the staff of the new school as lecturer in chemistry. Here he acquired considerable reputation as a lecturer, and three years later he was transferred to the newly-established Chair of Chemistry in the College of Surgeons’ School, which he held until 1850, when he was appointed to the University Chair of Che- mistry on the death of Dr. Francis Barker. Apjohn’s official con- nexion with the University began, however, in 1841. About that time the Board of Trinity College founded an Engineering School, and appointed Apjohn to the Chair of Applied Chemistry and Mineralogy—an office which he continued to hold when he succeeded Barker in 1850. On Dr. Apjohn’s retirement from professorial work, Mineralogy was transferred to the Chair of Geology in the University, and Applied Chemistry was permanently attached to the Chair of Chemistry. The principal scientific work of Dr. Apjohn was rather physical than chemical. The general study of hygrometry had a special attraction for him, and of the forty-nine scientific papers named in the Royal Society’s Catalogue, a large proportion relates to that subject. In the course of his work on the theory of the wet bulb hygrometer, he arrived at the expression well known as “ Apjohn’s Formula” for ascertaining the dew point. The study of hygrometry led to much interesting work on the specific heat of gases, and in 1837 Apjohn received the Cunningham VOL. XLI. b li Medal from the Irish Academy for his paper “Upon a New Method of Investigating the Specific Heats of the Gases.” The method con- sisted in noting the fall in temperature suffered by the wet bulb thermometer when immersed in the perfectly dry gas, whose specific heat was required. From 1838 onwards Dr. Apjohn devoted less attention to physical work than to mineralogical chemistry, He was a frequent contributor to the literature of the latter subject. In 1838 he analysed and described a mineral from Algoa Bay, South Africa, which proved to be a somewhat efficresced manganese alum, which has since been named ‘“ Apjohnite.” In 1840 he described a mineral found at Kilbricken, co. Clare, which is closely related to geocronite, but is non-arsenical. Again, in 1852 he was concerned in the description, under the name of “ Jellettite,” of a yellowish-green garnet found near Zermatt, Monte Rosa, by Dr. Jellett, the present Provost of Trinity College. Papers on the relations of pyrope, of pennine, and on Mexican hyalite are also to be found amongst his contributions to mineralogy. Dr. Apjohn contributed to the “‘ Cyclopedia of Practical Medicine” the articles on electricity, galvanism, toxicology, and spontaneous combustion, and it is stated that the latter article supplied Dickens with the facts on which he founded his account of Krook’s death in ** Bleak House.” As the representative of the University of Dublin in the General Medical Council, Dr. Apjohn took a prominent part in the production of the “‘ British Pharmacopeia.”’ Almost every chemical process and test described in the first edition of the “‘ Pharmacopceia’’ was care- fully examined in the Trinity College Laboratory, and much of the’ success of the work was due to Apjohn’s laborious revision in detail. He was elected to the Fellowship of the Royal Society in 1853; he was a Vice-President of the Royal Irish Academy; and at the time of his death was second on the roll of Fellows of the King and Queen’s College of Physicians. Dr. Apjohn was widely esteemed throughout his long life as a thorough and earnest worker, a singularly lucid and able lecturer, and an upright and honourable man. J. H. R. Witi1am Beysamin Carpenter was born at Exeter in 1813, and was the fourth child and eldest son of Dr. Lant Carpenter, a Unitarian minister. His sister, Mary Carpenter, who died a few years since, achieved the most important work as a philanthropist, in relation to the treatment of prisoners and to questions affecting our Indian fellow-subjects, and will be remembered by future generations with no less gratitude than her brother. In his childhood Dr: Carpenter received an excellent education, il comprising both classics and the principles of physical science, at the school established by his father at Bristol, and it was his intention to adopt the profession of a civil engineer. He was, however, persuaded to accept the opportunity offered by a medical practitioner, Mr. Hstlin, of Bristol, and to enter on the study of medicine as apprentice to that, gentleman. Shortly after this he was sent, as companion to one of Mr. Hstlin’s patients, to the West Indies, and on his return from this visit he entered, at the age of twenty, the medical classes of University College, London. After passing the examinations of the College of Surgeons and the Apothecaries’ Society he proceeded to Edinburgh, where he graduated as M.D. in 1839. His graduation thesis on ‘‘The Physiological Inferences to be deduced from the Structure of the Nervous System of Invertebrated Animals” excited considerable attention, especially on account of the views which he advanced as to the reflex function of the ganglia of the ventral cord of Arthropoda. From the first Dr. Carpenter’s work showed the tendency of his mind to seek for large generalisations and the development of philo- sophical principles. He was a natural philosopher in the widest sense of the term—one who was equally familiar with the fundamental doctrines of physics and with the phenomena of the concrete sciences of astronomy, geology, and biology. It was his aim, by the use of the widest range of knowledge of the facts of Nature, to arrive at a general conception of these phenomena as the outcome of uniform and all- pervading laws. His interest in the study of lhving things was not therefore primarily that of the artist and poet so much as that of the philosopher, and it is remarkable that this interest should have carried him, as it did, into minute and elaborate investigations of form and structure. Although some of his scientific memoirs are among the most beautifully illustrated works which have been published by any natural- ist, yet it is noteworthy that he himself was not a draughtsman, but invariably employed highly skilled artists to prepare his illustrations for him. Yet we cannot doubt that the man who, with his dominant mental tendency to far-reaching speculations, yet gave to the world the minute and ingenious analysis of the beautiful structure of the shells of Foraminifera, had an artist’s love of form, and that the part of his life’s work (for it was only a part among the abundant results of his extraordinary energy) which was devoted to the sea and the investigation of some of its fascinating living contents, was thus directed by a true love of Nature in which ulterior philosophy had no share. Two books, Dr. Carpenter has told us, exerted great influence over his mind in his student days: they were Sir John Herschel’s “ Dis- course on the Study of Natural Philosophy”’ and Lyell’s ‘‘ Principles of Geology ’’—that great book to which we owe the even greater books 1V of Charles Darwin. Taking the “ Principles” in some way as his model, Dr. Carpenter produced in 1839 his first systematic work, under the title “ Principles of General and Comparative Physiology, intended as an Introduction to the Study of Human Physiology and as a guide to the Philosophical Pursuit of Natural History.” Admir- able as was the execution of this work in many ways, its great merit lay in the conception of its scope. It was in fact the first attempt to recognise and lay down the lines of a science of “ Biology” in an educational form. Carpenter’s ‘‘ Comparative Physiology” is the general or elementary “‘ Biology”’ of the present day—traced neces- sarily upon the less secure foundations which the era of its production permitted, viz., one year only subsequent to the date of Schwann’s immortal “ Microscopical Researches.” For five years Dr. Carpenter remained in Bristol, commencing medical practice and marrying in 1840; but in 1844, feeling a distaste for the profession of medicine, he moved to London in order to devote himself entirely to a literary and scientific career. He was encouraged to take this step by the success which his “ Comparative Physiology ” obtained, a second edition having been called for within two years of the publication of the first. He was appointed Fullerian Professor of Physiology in the Royal Institution during his first year in London, and Professor and Lecturer at University College and at the London Hospital, whilst he was also elected a Fellow of the Royal Society. In 1851 Dr. Carpenter became Principal of University Hall, the residential institution attached to University College, where he remained until 1859. During this period he remodelled his treatise on Physiology, issuing the more general biological portion as ‘* Com- parative Physiology,” whilst that portion dealing with the special physiology of man and the higher animals appeared as his well-known “Human Physiology,” which subsequently ran through many editions. The ‘Human Physiology” is remarkable in the first place for the chapters on the physiology of the nervous system, and especially for the theories enunciated with regard to the relations of mind and brain, and the attempt to assign particular activities to particular portions of the cerebral structure. In arriving at his conclusions Dr. Carpenter had to depend on arguments drawn from the facts of comparative anatomy and of diseased or abnormal conditions in man. There is no doubt at the present day of the acuteness which he displayed in his treatment of the subject, and of the truth in a general way of the results which he formulated. Experiment and a wider range of observation have to some extent corrected—but on the whole rather ex- tended and confirmed—the doctrines of the early editions of the “‘ Human Physiology ” in regard to this subject, so that he was able only a few ~ years since to separate this portion of the work and issue it as a separate book, the “‘ Mental Physiology,” in which is contained by far Vy the most complete, consistent, and readable account of the phenomena of mind, and their relation to the actual structure of the brain, which exists. Such topics as Instinct, Mesmerism, Somnambulism, Uncon- scious Cerebration (his own phrase), &c., are discussed in a masterly way, and with an abundance of illustration and knowledge which renders the work one of the yreatest value even to those who may differ here and there from its theoretical conclusions. About the period of his removal to London Dr. Carpenter began to occupy himself with the minute study of the structure of the calca- reous Shells of the Mollusca—being led thereto by a desire to compare the results of the operation of living matter upon distinctly mineral compounds (such as carbonate of lime), by way of comparison and in illustration of the rapidly accumulating knowledge of cell-structure in the softer parts of living things. This study, which resulted directly in some valuable contributions to our knowledge of the structure of shells, shown by these researches to be far more complex than had hitherto been supposed, led on the one hand to Dr. Carpenter’s perma- nent identification with the pursuit of research with the microscope, and on the other hand to those admirable investigations of the struc- ture and law of growth of the shells of the minute Protozoic Foramin- ifera which constitute his most weighty contribution to the special literature of science. His microscopic studies bore fruit in the publication of ‘‘The Microscope and its Revelations,” the sixth edition of which was issued in 1881. The studies on the shells of Foraminifera were continued throughout his life, being published in four memoirs in the ‘“ Philosophical Transactions,” and in a richly illustrated monograph produced by the Ray Society in 1862, whilst the last of his memoirs in the *“‘ Philosophical Transactions” was that on Orbitolites bearing date so late as 1882. It was on this subject that Dr. Carpenter was busy at the time of his death, having during the past few years accumulated a wealth of material and arawings in support of his contention that the Hozoon canudense discovered by Logan in the Laurentian rocks of Canada exhibits the distinctive structure of the shell-substance of the higher Foraminifera. The material relating to Hozoon has been placed by Dr. Carpenter’s executors in the hands of Mr. Rupert Jones, who has undertaken to prepare it for publication. At the age of forty (1853), what with his. larger and smaller books, his original researches, his lectures on medical jurisprudence at University College, and numerous popular lectures on scientific topics, Dr. Carpenter’s life was unusually laborious and productive. In 1856 he was appointed Registrar of the University of London, and for twenty-three years administered the onerous duties of that office in such a way as to contribute in no small degree to the success of the University, and above all to the maintenance of the high b 2 v1 character of its degrees and the ample recognition of the study of © natural science for which the University is now distinguished. He was able now to give a larger amount of time than formerly to his original investigations, and, in his summer holidays at Arran and elsewhere, commenced, amongst other studies, those researches on the structure and development of the beautiful little feather-star, which were from time to time published in the “ Philosophical Transactions,” and led to his association with Wyville Thomson, and thus to the deep-sea explorations of the ‘‘ Lightning,” and subsequently of the ‘“‘ Challenger.” Carpenter’s memoirs on Comatula give a very full and beautifully illustrated account of the structure of the skeleton of the feather-star, but for many years the view which he entertained with regard to the nature of the axial cord which runs through the segments of the arm- skeleton of that animal was regarded by all other observers (with scarcely an exception) as erroneous. Dr. Carpenter considered these cords as nerve-cords, and in the Easter vacation of 1876 he made a special visit to the marine laboratory erected by Dr. Dohrn at Naples, in order to test his views by the repetition, on an extensive scale, of experiments which had already appeared convincing to his mind. These experiments, and others since carried out by younger natural- ists, have at length fairly established the view for the truth of which the veteran observer had long contended. In December, 1875, Dr. Carpenter had communicated to the Royal Society the outlines of his work on the soft parts of Antedon (Coma- tula) rosacea, and on returning from Naples he communicated a supplemental note to the Society on the subject of the nervous system of that animal (‘“ Roy. Soc. Proc.,” vol. 24, 1876, p. 451). He lived to see his conclusions, first formulated in 1865 (‘ Phil. Trans.,” vol. 156, p. 705), fully confirmed by the experiments of Marshall (‘“‘ Quart. Journ. Micro. Sci.,” vol. 24, 1884) and by those of Jickeli of Jena (‘‘ Zool. Anzeiger,” No. 170, 1884). Important evidence in favour of these conclusions was also furnished by the anatomical investigations of Dr. P. Herbert Carpenter on the allied genus Actinometra (‘‘ Journal of Anatomy and Physiology,” 1876). M. Ed. Perrier of Paris, who had strenuously opposed Dr. Carpenter’s conclusions, was thus led to renewed observations and to a complete acceptance of their correct- ness (‘Comptes Rendus,” July, 1883, p. 187), whilst the most care- ful student of Echinoderm anatomy among German zoologists, viz., Dr. Ludwig, who had also previously opposed these conclusions, has now endorsed them. Thus in the “ Roy. Soc. Proc.,” vol. 37, 1884, p. 67, Dr. Carpenter was able to give a complete history of the question, showing how the opposition on theoretical grounds to the view that the axial cords of Comatula were nerve-cords, had gradually given way before an appeal to observation and experiment.. This vii record of the final triumph of the view which he had originated and so long laboured to establish was the last scientific paper published by Dr. Carpenter. The deep-sea explorations which Dr. Carpenter, assisted by Pro- fessor Wyville Thomson, arranged, and for which he succeeded in obtaining the aid of ships of the Royal Navy, were designed not merely to search for organisms in the great depths of the ocean, but especially to study the ocean currents both deep and superficial, Dr. Carpenter having a strong desire to enter upon the explanation of the great physical phenomena presented by the ocean. He himself took part in the earlier expeditions in 1868 and subsequent years, and though unable to leave the ties which bound him to home, so as to join the “Challenger”? Expedition, yet he closely watched the results then obtained, and embodied the whole of his observations, and those reported from the “ Challenger,” in some extremely suggestive and important memoirs and lectures on ocean circulation. These are as follows :—Reports in the “ Proceedings of the Royal Society” on the several cruises of the “Lightning” (“Roy. Soc. Proc.,” 1868), “Porcupine” (ibid., 1869-70), “Shearwater” (cbid., 1871), and *“Valorous”’ (ibid., 1875); a series of memoirs in the “ Roy. Geograph. Soc. Proc.,” 1871, 1874, 1875, 1877; lectures delivered to and printed by the Royal Institution of London and the United Service Institution; articles in the ‘‘Contemporary’”’ and the ‘“ Nine- teenth Century ’”’ Reviews. The more general philosophical views held by Dr. Carpenter, and his conceptions in regard to those topics where science touches religion, may be gathered from a series of articles published by him in the “Modern Review” during the years 1880-84, the titles of which are as follows:—‘‘The Force behind Nature,” “ Nature and Law,” ‘‘Charles Darwin; his Life and Work,” “The Doctrine of Evolution and its Relations to Theism,” ‘‘ The Argument from Design in the Organic World.”’ In 1879 he retired from the Registrarship of the University of London with a well-earned pension, and was at once chosen as a member of the Senate of that body. He now devoted himself with unabated vigour to the prosecution of his studies on Foraminifera and on Comatula, and to more theoretical matters, such as ocean-currents, and the explanation of the frauds of spirit-mediums. Though released from the duties of office, he was still a constant attendant at the Senate of the University, he rarely missed a meeting of the Royal Society or one of the annual gatherings of the British Association, and, besides undertaking the administration of the Gilchrist Trust, delivered many lectures in all parts of the country himself—both independently and as an emissary of the trustees. The scheme of lectures and scholarships instituted by the Gilchrist trustees, which vill is effecting important educational results in nataral science among classes of society excluded from regular University teaching, is Dr. Carpenter’s work. He wrote at this time in the interest of the public health some admirable articles on vaccination, as in earlier life (1849) he had from a similar point of view treated the subject of alcoholic liquors, and had urged the arguments for total abstinence. When past seventy years of age he did not shrink from a journey to the United States, where he spoke and lectured with unflagging vigour. The last public movement in which he took an active part was the foundation of the Marine Biological Association, of which he was a Vice-President, and which is about to carry out, by means of its laboratory on Plymouth Sound, a suggestion which is traceable to his own proposition for the thorough exploration and study of Milford Haven. The abundant and noble achievements of Dr. Carpenter’s public and scientific career did not pass without recognition in the form of awards and titles. He received in 1861 one of the Royal medals awarded by the Council of the Royal Society, and in 1883 the Lyell medal of the Geological Society. In 1871 he was made an honorary LL.D. of the University of Edinburgh, and in 1872 he was President of the British Association for the Advancement of Science when it met at Brighton. In 1873 he was elected Corresponding Member of the Institute of France, and on his retirement from his official position at the Univer- sity of London in 1879 he was nominated C.B. It is impossible to do justice to Dr. Carpenter’s character as a scientific man in a few lines: here no attempt has been made to do more than indicate in something like chronological order and con- nexion of subjects the vast amount of work which he accomplished. Upon the present writer, whose father was his fellow-student at University College, and who has enjoyed since boyhood the privilege of his friendship, Dr. Carpenter always produced the most vivid impression of a man of indomitable energy, who had accepted as the highest duty and keenest delight of his life the promotion, whether by advocacy or by research, of true knowledge. The tenacity and vigour with which he was wont to expound his views on such matters of research as at the time occupied his thoughts, and the importance and respect which he assigned to all genuine research, were evidences of an earnest and just nature which evoked sympathy and esteem in all men of kindred pursuits. In reference to Dr. Carpenter’s private life and tastes, the following extract from a weekly journal states, with the authority of a member of his own family, what might, in its absence, have been here less completely indicated. The journal to which we are thus indebted is an organ of the Unitarian Church, of which body Dr. Carpenter was, throughout life, an active and orthodox member, a fact which may or 1X. may not be brought into connexion with the fact of his incomplete acceptance of the leading doctrines of Darwinism. ‘« He was well versed in literature, and turned for refreshment in hours of weariness to his favourite Scott. Political memoirs of his own time were read with the keenest relish, for he had early learned from his father, Dr. Lant Carpenter, to take a high view of a citizen’s obligations, and the Bristol riots, which he had witnessed, made a life-long impression upon him. A brief sojourn in Italy called forth a susceptibility to the enjoyment of art which was a surprise even to himself ; and in music, from the time that he had taught himself as a young man to play on the organ, he found unfailing recreation. Nature, likewise, in her vaster as well as her microscopic forms, was for him full of charm and delight, and from every excursion he carried back memories which remained singularly vivid and distinct. In society his immense stores of information, his sympathetic interest in others, his thorough enjoyment of humour. though he felt unable to originate it, made him a genial and ever-welcome companion, while his friends learned how strong a confidence might be piaced in his faithfulness. Many young men found unexpected help and encourage- ment in him, and he rejoiced when he could open a way to those who were involved in the struggles through which he had himself once passed. The dominant conception of his lfe—as was fitting in one of Puritan descent—was that of duty. And if this sometimes took austere forms, and Jed him to frame expectations which others could not always satisfy, an enlarging experience mellowed his judgment and enabled him to apprehend their position from their point as well as hisown. Released from the pressure and strain of earlier life, he was able to give freer play to his rich affections; and in his own family they only know what they have lost who will never again on earth feel his support as husband and father, brother and friend.”’ H. R. LL. Wituam Wittovcusy Corn, third Earl of Enniskillen, was born on the 25th of January, 1807, succeeded to the title and estates in March, 1840, and died at Florence Court, co. Fermanagh, on Friday, the 12th of November, 1836, after only a few days’ illness. He sat as Baron Grinstead in the House of Lords. Lord Enniskillen was educated at Harrow and at Christ Church, Oxford, but never graduated. While at Oxford he devoted much time and attention to Geology and Paleontology, assiduously attending the lectures delivered by the Rev. Dr. Buckland. In conjunction with the late Sir Philip de Malpas Grey Hgerton, his friend and college companion, Lord Enniskillen commenced collecting organic remains in the neighbourhood of Oxford and. other parts of the British Islands; together they ultimately succeeded c x in obtaining a most extensive, complete and valuable collection of Fossil Fishes; probably the largest in the world. From that period antil the death of Sir Philip Egerton they were joint collectors, scrupulously dividing their acquisitions, and that so industriously, that nearly the same species occurred m each cabinet; it was owing to this wnion of partnership that the two collections were so inti- mately interwoven, and for the interest of Ichthyic Paleontology inseparable; hence their subsequent possession by the nation, and united preservation in the galleries of the British Museum of Natural History, Cromwell Road. Three years previous to Lord Enniskillen’s death (1883), that portion contained in the Florence Court Collection was purchased by the trustees of the British Museum, through a special grant from the Treasury. Lord Enniskillen* and Sir Philip Egerton, after leavme Oxford, travelled through much of Germany, Switzerland, and Italy, solely for the purpose of studying and eolleeting one group of the Vertebrata, and to this large division of the animal kingdom they appear always to have restricted their researches; their contimental journey was also undertaken to still more perfect their kwowledge of stratigra- phical Geology, in connexion with them palzontological researches ; how completely this was continued, and carried on until both our distinguished Fellows were removed by death, is fully exemplified by the union of the two great collections—or that of Florence Court and that of Oulton Park—now arranged together in the galleries of the British Museum of Natural History. Lord Enniskilten also particularly examined the caves of Germany, Belgium, &c., obtaining from Gailenreuth, Kuhloch, and Hagis, a rich series of bones illustrating the remains of extinct Mammalia, especially those of the hon, mammoth, rhimoceros, hysena, and rein- deer. - At home and abroad every locality and geological horizon yielding the remains of fish attracted Lord Enniskillen’s attention, who never failed to secure every good as well as new form for his Florence Court Collection, duplicates whenever they occurred being also added to the Oulton Park Museum by Sir Philip: Egerton. This dual possession and study of Fossil Ichthyology arose through their intimate acquaintance in 1830 and subsequent years with Agassiz, who impressed upon them the importance of confining them- selves to one line or branch of research; the result of whieh has been the formation of these two unrivalled collections of Fossil Fish, the history of which, through the works of Agassiz and Six Philip Egerton, has greatly enriched the literature of this extensive division in Zoology, especially as regards structure and distribution. * Then Viscount Cole. xi Lord Enniskillen never published any particulars of, or described any species of Fossil Fishes, but the Florence Court MS. catalogue was kept with the most scrupulous care, every specimen being recorded with all details essential to the zoological position, strati- graphical and geographical history of the species in so great a collection; and this was carried out in every detail. This applied not only to the Florence Court catalogue, but also to the almost duplicate volume of the Oulton Park Collection, kept with the same care by Sir Philip Egerton; so that the enumeration of species contained in one, without reference to the other, would be incomplete and unsatisfactory. Lord Enniskillen paid considerable attention to Archeology, especially that relating to Ireland, and was one of the first to call attention to the lake dwellings in that country. Lord Enniskillen’s public services were great, as also indeed had been those of the long line of bis ancestors through nine generations, ever since their settlement in Ireland in the year 1612. He sat as M.P. for Fermanagh from the year 1831 to 1840; was Colonel of the Fermanagh Militia from 1834 to 1875, and Hon. Colonel from 1875, and for more than fifty years leading member of the Orange Society, Grand Master of the County of Fermanagh, Grand Master of Ireland, and imperial Grand Master. He was also one of the Trustees of the Hnunterian Museum. He received the honorary degree of D.C.L. from the University of Oxford, and thatof LL.D. from the University of Dublin and the University of Durham. Lord Enniskillen was elected F.R.S. in the year 1829, and was thus a Fellow of our Society for fifty-seven years. R. EH. Tuomas ANDREWS was born at Belfast on the 19th December, 1813. His father was a linen merchant in good position. He received his early education at the Belfast Academy and at the Royal Academical Institution of Belfast. He then went to Glasgow to study chemistry under Professor Thomas Thomson, whose laboratory was then one of ‘the very few places in this country where systematic instruction in real chemistry was regularly given to students. He continued his studies in Trinity College, Dublin, where he distinguished himself koth in Science and in Classics; and, after spending some time in Dumas’ laboratory in Paris, went to Edinburgh, where he took the degree of Doctor of Medicine in 1835. Returning to Belfast, he devoted himself to the practice of medicine, in which he was very successful. In 1845 he was the first Lecturer on Chemistry in the Royal Belfast Academical Institution, but held this office for a short time only. In 1845 the Queen’s Colleges were founded and Andrews was appointed Vice-President of the Belfast College. With this office Xl there was conjoined, when the preliminary arrangements had been made, that.of the Chair of Chemistry. He held these offices till 1879, when the state of his health induced him to resign them, and to retire almost completely from active work. He continued to take a keen interest in the progress of Science till his death on the 5th November, 1885. He was elected a Fellow of the Royal Society in 1849, he was an Honorary Fellow of the Royal Society of Edinburgh, and a Corre- sponding Member of the Royal Society of Gottingen. He received honorary degrees from various Universities. He presided over the Chemical Section of the British Association at Belfast in 1852, and again at Edinburgh in 1871, and was President of the Association at the Glasgow Meeting in 1876. In 1842 Dr. Andrews married Jane Hardie, daughter of Major Walker of the 42nd Highlanders. He is survived by Mrs. Andrews, by three daughters and by two sons, the elder of whom is Major in the Devonshire Regiment, and the younger a member of the Irish Bar. Dr. Andrews was deeply interested in public affairs, but very rarely took an active part in politics, and was quite free from party spirit. His only writings bearing in any way on political matters are ‘ Chapters - of Contemporary History.’ The first, entitled ‘‘Studium Generale,” and published in 1867, is a historical and critical discussion of the function of a University, with special reference to the Queen’s Colleges. The second, ‘The Church in Ireland,” was published in 1869. Of Dr. Andrews’ strictly Chemical papers we may mention one on the blood of cholera patients, in which he showed that it differs from normal blood only by having a smaller proportion of water; one on galvanic cells with strong sulphuric acid as the exciting liquid, and one on the presence of metallic iron in basaltic and other rocks. Much more important than these careful and interesting papers is his great work on Ozone. ‘This mysterious body had been the subject of in- vestigations by its discoverer, Schdnbein, and also by Marignac, De la Rive, Berzelius, Williamson, Fremy and Becquerel and Baumert, but its real nature was still unknown, it was not even certain that a number of different substances had not been confounded under the name. That ozone, however prepared, contained oxygen, and was a powerful oxidising agent was certain, but it was not clear that it did not, some- times at least, contain hydrogen also. Andrews attacked the problem with characteristic energy and straightforwardness. By a series of experiments, in which it is difficult to say whether the ingenuity, the perfect fitness for their purpose, or the wonderful simplicity of the methods used is to be most admired, he proved that ‘‘ozone, from what- ever source derived, is one and the same body, having identical Xill properties and the same constitution, and is not a compound body, but oxygen in an altered or allotropic condition.” This work was continued by Andrews and Tait, and the results were published in the ‘ Philosophical Transactions’ under the title “‘ On the Volumetric Relations of Ozone and the Action cf the Hlectrical Dis- charge on Oxygen and other Gases.” The theory of the constitution of ozone now universally held is clearly indicated in this paper, although its apparent improbability deterred the authors from dis- cussing it fully. But by far the most interesting and peculiar part of Dr. Andrews’ work is to be found in his investigations in the borderland between Chemistry and Physics. There his special ability, his power of arranging experiments, of devising pieces of apparatus suited to the particular purpose at the moment in view, of detecting sources of error and providing simple effective means of avoiding them, and of doing all this himself with the least possible help from the instrument maker, comes into remarkable prominence. The apparatus with which most of his work was done was made with his own hands, and when, for instance, he wanted a casting, he personally superintended the minutest details. This directness of his work, and his habit of working alone, made him somewhat intolerant of assistance, as it made him independent of it. The only exception to the solitariness of his scientific work, a very notable exception, is the investigation of Ozone, carried out in conjunction with Professor Tait. His researches on the heat developed in chemical actions, for one of which he received in 1844 one of the Royal Medals, and for the other in 1850 one of the prizes given by the French Academy of Sciences, and that on the continuity of the liquid and gaseous states, partly contained in his Bakerian Lectures, and partly communicated posthumously to the Society, were done strictly alone. If this independence and individu- ality limited the amount of work done by him, it has the compensating advantage that we know that every analysis and every observation published by him were actually made with his own hands and eyes, so that a reader of his paper is as nearly as possible in as good a position to judge as to the soundness of his conclusions as if he had performed the experiments himself. In reading his papers we are transported at once to the laboratory; without wearisome repetition we have all the details before us, and we can follow every step of his argument as if we had been present at every experiment on which it was founded. The investigation into the heat given out during chemical action was begun while he was still engaged in medical practice; this work at once established his position as a genuine scientific discoverer, and introduced him to the chemists and physicists of Hurope. But the work which will always be most closely connected with his name is the great investigation into the relation of temperature, pres- X1V sure and volume of carbonic acid, communicated to this Society in the Bakerian Lectures of 1869 and 1876. He showed that for temperatures below about 30°9° C. as the pressure is increased we come to a point where condensation occurs, where the gas is converted into a liquid. At this pressure there are two limiting values of the volume, one when all the substance is vapour, and one when it is all liquid. Between these the substance is partly vapour and partly liquid, the distinction between the two being visible, as the liquid and the vapour refract light differently, and are separated from one another by a distinct meniscus. As the temperature ‘approaches 30°9° the abrupt change of volume on con- densation becomes less and less in amount, above that temperature (the Critical Temperature of carbonic acid) there is no abrupt change of volume, and no visible condensation. Near 30-9°, but above it there is a rapid, but not abrupt, change of volume; as the temperature rises this rapid change of volume becomes less and less marked, and the isothermal approximates more and more to the hyperbolic form. This extraordinary character of the isothermals—discontinuous below a particular temperature, continuous above it—led Andrews to the remarkable discovery which gives the title to his Lectures, “ The Continuity of the Gaseous and Liquid States of Matter.” If we represent the relation of temperature, pressure and volume by means of a surface, where the rectangular co-ordinates w, y, and z correspond to p, t,and v (as was dene by Professor James Thomson to illustrate Andrews’ work), we see that there is what may be called a cliff, points at the top of which correspond to the substance at the condensing point, but all in the state of vapour, while points imme- diately below them, at the base of the cliff, correspond to the substance just condensed and all in the state of liquid. The cliff becomes less and less high as a and y increase, and vanishes at the place correspond- ing to the critical point. From a point on the slope above the cliff Wwe can pass to a point on the slope below, either by dropping down the vertical face or by going round the end of the cliff. To quote Andrews’ words “ . . . . the author has made carbonic acid pass, without breach of continuity, from what is universally regarded as the gaseous to what is, in like manner, universally regarded as the liquid state. As a direct result of his experiments, he concludes that the gaseous and liquid states are only widely separated forms of the same condition of matter, and may be made to pass into one another by a series of gradations so gentle that the passage shall nowhere present any interruption or breach of continuity. From carbonic acid as a perfect gas to carbonic acid as a perfect liquid, the transition may be accomplished by a continuous process, and the gas and liquid are only distant stages of a long series of continuous physical changes. Under certain conditions of temperature and pressure, carbonic acid finds xv itself, it is true, in a state of instability, and passes, without change of pressure or temperature, but with evolution of heat, to a condition which, by the continuous process, can only be reached by a long and circuitous route.” Like most great discoveries, this had been to a certain extent fore- shadowed. In 1822 Cagniard de la Tour observed that certain liquids —ether, alcohol, water—when heated in hermetically elosed tubes, were apparently totally changed into vapour occupying from two to four times the original volume of the liquid. In 1825 Faraday succeeded in condensing to liquids a number of substamces previously known in the gaseous state only. Shortly afterwards Thilorier obtained solid carbonic acid, and observed the very rapid expansion of liquid carbonie acid when heated. In 1845 Faraday published a very remarkable paper im the ‘ Philoso- phieal Transactions’ on the liquefaction and solidification of gases. He there pointed out that as different liquids assume the Cagniard de la Tour state at different temperatures, so the gases which had not been econdensed— oxygen, hydrogen, nitrogen, &¢.—might be supposed to have that point below the lowest temperature he had applied (that of a bath of solid earbonic acid and ether in vacuo), and therefore to be incapable of condensation to a liquid by any pressure unless the temperature were much further lowered. Faraday conjectured from the results of experiment that the Cagniard de la Tour state oecurred im the case of carbonic acid about 90° F., a value surprisingly near that experimentally proved by Andrews. But what others had seen obscurely or partially, or had inferred, Andrews made clearly visible in its entirety, and many physicists and chemists can testify to the startling eharaeter of the revelation made by the publication of his discovery. It is in fact after the discovery has really been made that the historian begins to look for foreshadow- ings, and we are perhaps somewhat inclined to interpret these early indications in the light of the later, more definite knowledge, but the unanimous verdict of the scientific world is that the discovery of the continuity of the liquid and gaseous states belongs to Andrews and to him alone. Dr. Andrews was loved by all who knew him. Warmly hospitable, he was personally almost stoically temperate, allowing himself the minimum of rest, of food, and of sleep. While in theological, as in all other matters, he thought for himself, he was a consistent and orthodox Christian and a loyal member of the Church of Ireland. patos Ope 8 INDEX to VOL. XLI. ADDRESS of the President, 373. Air, the determination of organic matter in (Carnelley and Mackie), 238. - the coefficient of viscosity of. pendix (Tomlinson), 315. further experiments on the dis- tribution of micro-organisms in (Frankland and Hart), 446. Anderson (T.) on a varying cylindrical lens, 4.60. Andrews (Thomas), obituary notice, x1. Anniversary meeting, 372. address, 373. Apjohn (James), obituary notice, i. Atmosphere, quantitative estimation of micro-organisms present in the (Frank- land), 443. Auditors elected, 248. report of, 372. Ap- Balance sheet, 387. Bee (honey), geometrical construction of the cell of the, note to a paper on the (Hennessy), 442. Brachial plexus, the minute anatomy of the (Herringham), 423. Brown (J.), a theory of voltaic action, 294. Brown (J. G.), C. 8. Roy, and C. S. Sherrington, preliminary report on the pathology of Cholera Asiatica (as observed in Spain, 1885), 173. Callendar (H. L.) on the practical measurements of temperature. Ex- periments made at the Cavendish Laboratory, Cambridge, 231. Calorimetry, on the method of eondensa- tion in (Joly), 248, 352. Carbonic acid, an instrument for the speedy volumetric determination of (Marcet), 181. Carnelley (T.) and W. Mackie, the determination of organic matter in air, 238. Carpenter (William Benjamin), obituary notice, il. Cash (J. T.), contribution to the study of intestinal rest and movement, 212. Cell of the honey bee, note to a paper on the geometrical constructionof the . (Hennessy), 442. VOL. XLI. | Chlorophyll, contributions to the chemistry of. No. II. (Schunck), 465. Cholera Asiatica, preliminary report on the pathology of (as observed in Spain, 1885) (Roy, Brown, and Sherrington), 173. Condensation in calorimetry, on the method of (Joly), 248, 352. Conductivity of rocks, on underground temperatures; with observations on the (Prestwich), 1. Council, nomination of, 317. election of, 386. Cylindrical lens, on a varying (Ander- son), 460. Darwin (Capt.), preliminary account of the observations of the eclipse of the sun at Grenada in August, 1886, 469. Darwin (G. H.), on Jacobi’s figure of equilibrium for a rotating mass of fluid, 319. —- on the dynamical theory of the tides of long period, 337. Dewar (J.) and G. D. Liveing, note on a new form of direct vision spectro- scope, 449. Dielectric constants of fluids (Quincke), 458. Donation Fund, account of grants from the, in 1885-86, 399. Dynamical theory of the tides of long period, on the (Darwin), 337. Earth’s crust, on the agency of water in volcanic eruptions ; with some obser- vations on the thickness of the (Prest- wich), 117. Eclipse of the sun at Grenada in August, 1886, preliminary account of the observations of the (Darwin), 469. Enniskillen (Karl of), obituary notice, ix. Entyloma Ranunculi (Bonorden), on the structure and life-history of (Ward), 318, Fellows deceased, 372. withdrawn, 372. — elected, 373. number of, 386. | Figure of equilibrium for a rotating d XVill mass of fiuid, on Jacobi’s (Darwin), 319. Financial statement, 387. Fishes, on the intra-ovarian egg of some osseous (Scharff), 447. Frankland (P. F.),a new method for the quantitative estimation of the micro- organisms present in the atmosphere, - 443. ; -—— and T. G. Hart, further experi- ments on the distribution of micro- organisms in air (by Hesse’s method), 446. Geometrical construction of the cell of the honey bee, note to a paper on the (Hennessy), 442. Germination, on the changes in the proteids in the seed which accompany (Green), 466. Government Grant of 4,000/., account of the appropriation of the, 396. Grants from the Donation Fund in 1885- 86, 399. Green (J. R.) on the changes in the proteids in the seed which accompany germination, 466. Hart (T. G.) and P. F. Frankland, further experiments on the distribu- tion of micro-organisms in air (by Hesse’s method), 446. Heart, on the action of the excised mammalian (Waller and Reid), 461. Hennessy (H.), note to a paper on the geometrical construction of the cell of the honey bee (‘ Roy. Soc. Proc.,’ vol. 39. p. 253), 442. Herringham (W. P.), the minute anatomy of the brachial plexus, 423. Hopkinson (J.), note on specific induc- tive capacity, 453. addendum (Quincke), 458. Iceland spar, on the effect of polish on the reflexion of light from the surface of (Spurge), 463. Intestinal rest and movement, contribu- tion to the study of (Cash), 212. Intra-ovarian egg of some osseous fishes, on the (Scharff), 447. Jacobi’s, on, figure of equilibrium for a rotating mass of fluid (Darwin), 319, Joly (J.) on the method of condensation in calorimetry, 248, 352. on the specific heats of minerals, 250. Kew Committee, report’ of the, 400. Lens, on a varying cylindrical (Ander- son), 460. INDEX. Light, on the effect of polish on the reflexion of, from the surface of Ice- land spar (Spurge), 463. —— reflected from certain surfaces at nearly perpendicular incidence, on the intensity of (Rayleigh), 275. Liveing (G. D.) and J. Dewar, note on a new form of direct vision spectro- scope, 449. Mackie (W.) and T. Carnelley, the de- termination of organic matter in air, 238. Mammalian heart, on the action of the excised (Waller and Reid), 461. Marcet (W.), an instrument for the speedy volumetric determination of carbonic acid, 181. Medals, presentation of the, 383. Micro-organisms in air, further experi- ments (by Hesse’s method), on the distribution of (Frankland and Hart), 44.6. present in the atmosphere, a new method for the quantitative estimation - of the (Frankland), 4.43.. Minerals, on the specific heats of (Joly), 250. Minute anatomy of the brachial plexus (Herringham), 423. Mountain ranges, on underground tem- peratures; with observations on a special source of heat in (Prestwich), ils Obituary notices of fellows deceased :— Andrews, ‘Thomas, x1. Apjobhn, James, 1. Carpenter, William Benjamin, 1. Enniskillen, Harl of, ix. Officers, nomination of, 317. election of, 386. Organic matter in air, the determination of (Carnelley and Mackie), 238. Osseous fishes, on the intra-ovarian egg of some (Scharff), 447. Owen (Sir R.), additional evidence of the affinities of the extinct marsupial quadruped, Thylacoleo carnifex, Ow., 317. Photometry of the stars (Pritchard), 195. Presents, lists of, 343, 471. President, address of the, 373. Prestwich (J.) on underground tempe- ratures; with observations on the conductivity of rocks; on the thermal effects of saturation and imbibition ; and on a special source of heat in mountain ranges, 1. on the agency of water in volcanic eruptions ; with some observations on INDEX. the thickness of the earth’s crust from a geological point of view; and on the primary cause of volcanic action, 117. Pritchard (C.), researches in stellar photography. 1. In its relation to the photometry of the stars; 2. Its applicability to astronomical measure- ments of great precision, 195. Proteids in the seed, on the changes in the, which accompany germination (Green), 466. Quincke (G.), addendum to ‘ Note on specific inductive capacity ’ (Hopkin- son),—Notiz tiber die Dielectricitits- constante von Flissigkeiten, 458. Rayleigh (Lord) on the intensity of light reflected from certain surfaces at nearly perpendicular incidence, 275. Reid (HE. W.) and A. Waller on the action of the excised mammalian heart, 461. Roy (C. 8.), J. G. Brown, and C. S. Sherrmeton, preliminary report on the pathology of Cholera Asiatica (as observed in Spain, 1885), 173. Saturation and imbibition, on under- ground temperatures ; with observa- tions on the thermal effects of (Prest- wich), 1. Scharff (R.) on the intra-ovarian egg of some osseous fishes, 447. Sechunck (E.), contributions chemistry of chlorophyll. 465. Seed, on the changes in the proteids in the, which accompany germination (Green), 466. Sherrington (C. S.), ©. 8S. Roy, and J. G. Brown, preliminary report on the pathology of Cholera Asiatica (as observed in Spain, 1885), 173. to the No. II, Specific heats of minerals, on the (Joly), _ 250. inductive capacity, note on (Hop- kinson), 453. addendum (Quincke), 458. Spectroscope, note on a new form of direct vision (Liveing and Dewar), 449. Spurge (C.), on the effect of polish on X1X the reflexion of light from the surface of Iceland spar, 463. Stellar photography, (Pritchard), 195. ‘Stereoscope,’ note on a paper entitled ‘on a new form of’ (Stroh), 274. Stroh (A.), note on a paper entitled ‘On a new form of stereoscope,’ 274. Sun, preliminary account of the observa- tions of the eclipse of the, at Grenada in August, 1886 (Darwin), 469. researches in Temperature, on the practical measure- ments of (Callendar), 231. Thurlow (Lord), admitted, 248. Thylacoleo carnifex, Ow., additional evidence of the affinities of the extinct marsupial quadruped (Owen), 317. Tides of long period, on the dynamical theory of the (Darwin), 337. Tomlinson (H.), the coefficient of vis- cosity of air. Appendix, 315. Trust funds, 391. Underground temperatures, on, with observations on the conductivity of rocks, on the thermal effects of satura- tion and imbibition, and on a special source of heat in mountain ranges (Prestwich), 1. Vice-Presidents appointed, 4.42. Viscosity of air, the coefficient of. Appendix (Tomlinson), 315. Volcanic eruptions, on the ageney of water in; with some observations on the thickness of the earth’s crust from a geological point of view; and on the primary cause of volcanic action (Prestwich), 117. Voltaic action, a theory of (Brown), 294. Volumetric determination of carbonic acid, an instrument for the speedy (Marcet), 181. Waller (A.) and E. W. Reid on the action of the excised mammalian heart, 461. Ward (H. M.) on the structure and life-history of Entyloma Ranunculi (Bonorden), 318. Water in volcanic eruptions, on the agency of (Prestwich), 117. END OF FORTY-FIRST VOLUME. HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN’S LANE. 1X may not be brought into connexion with the fact of his incomplete acceptance of the leading doctrines of Darwinism. ‘“* He was well versed in literature, and turned for refreshment in hours of weariness to his favourite Scott. Political memoirs of his own time were read with the keenest relish, for he had early learned from his father, Dr. Lant Carpenter, to take a high view of a citizen’s obligations, and the Bristol riots, which he had witnessed, made a life-long impression upon him. A brief sojourn in Italy called forth a susceptibility to the enjoyment of art which was a surprise even to himself ; and in music, from the time that he had taught himself as a young man to play on the organ, he found unfailing recreation. Nature, likewise, in her vaster as well as her microscopic forms, was for him full of charm and delight, and from every excursion he carried back memories which remained singularly vivid and distinct. In society his immense stores of information, his sympathetic interest in others, his thorough enjoyment of humour though he felt unable to originate it, made him a genial and ever-welcome companion, while his friends learned how strong a confidence might be piaced in his faithfulness. Many young men found unexpected help and encourage- ment in him, and he rejoiced when he could open a way to those who were involved in the struggles through which he had himself once passed. The dominant conception of his lfe—as was fitting in one of Puritan descent—was that of duty. And if this sometimes took austere forms, and Jed him to frame expectations which others could not always satisfy, an enlarging experience mellowed his judgment and enabled him to apprehend their position from their point as well as hisown. Released from the pressure and strain of earlier life, he was able to give freer play to his rich affections; and in his own family they only know what they have lost who will never again on earth feel his support as husband and father, brother and friend.” fe Roe On the Agency of Water in Volcanic Eruptions. 173 The lost of terrestrial heat by radiation is now exceedingly small. But small as this loss is, 1t cannot take place without producing con- traction, and Cordier long since calculated that supposing five volcanic eruptions to take place annually, it would take a century to eject so much lava as would shorten the radius of the earth to the extent of 1 mm., or about ,); inch. I therefore conclude that the hypothesis originally propounded, namely, that voleanic phenomena are dependent on the effect of secular refrigeration is, with certain modifications, the one that best meets the necessities of the problem. The Determination of Organic Matter in Arr. 247 definite intervals the carbonic acid and organic matter present in the air of the room were determined, the analyses being made in the room itself so as to avoid opening the door. The room being un- provided with outside light, one gas jet was kept burning during the whole of the experiments, but the effect of this on the organic matter may be neglected, for, as previously shown, the combustion of coal gas does not appreciably increase the amount of organic matter. The results obtained are shown below :— | Outside After 20 | After 30 | After 60 | After 100 air. minutes. | minutes. minutes. | minutes. hy CO, 3°8 11 °4 14°8 — — Ist experiment eae 9°5 12°9 14.°8 ‘ie of Deecpeeinent ee Ae es 118)01L 23 °5 28-2 O.M. Be ae 14 °2 15 °9 17:0 8rd experiment on ae 1 17 °2 24°] 321 O.M. oe Ps 13°5 1S 2r/ 20°3 Here it is seen that the amount of organic matter becomes greater as the period of vitiation increases, but very much less slowly, so that the increase in the quantity of organic matter is by no means pro- portional to the time. It also increases less rapidly than the carbonic acid. (8.) An atmosphere which has been entirely at rest for some time is found to contain less organic matter than it did previously. This is not necessarily entirely due to the settling down of the solid organic dust, but is probably due in part to oxidation. The statement made in ‘ Nature’ (vol. 33, 1886, p. 180), in an article on ventilation, to the effect that the organic matter in respired air increases part passu with, and is therefore estimated by the amount of carbonic acid present, may be true when the average of a large number of determinations is taken, but is certainly very far frora being true in individual cases. At any rate the amount of carbonic acid is no certain index of the quantity of organic matter present in an atmosphere (see above). That air in which respiration has gone on for some time gives invariably a higher result than outside air at or about the same time is all that can be confidently affirmed. It should not be forgotten that the organic matter in air is most — probably partly solid and partly gaseous. The golid obeying a different law than diffusion slowly settles down, whilst the gaseous part, unlike carbonic acid, is most likely an unstable compound or compounds, and readily undergoes oxidation. Hxperiments were made in regard to this, but they did not give decisive results. On the Method of Condensation in Calorimetry. BLL Complete Formula for Calculating the Specific Heat. Collecting the foregoing corrections we get a formula for use if very considerable accuracy be desirable, but it is to be observed that under any ordinary circumstances correction (1) on w, of —V x 000063 is sufficient. The complete formula for 8, the specific heat, is— g_ 1:000589[w, —V x 0:000636][536-5 +.0°7(100—#,°)] Wi) ha) the several weights observed b2ing supposed reduced to vacuo as usual, otherwise the letters being as before. The Minute Anatomy of the Brachial Plexus. 44] Radial.* Deltoid from scapula. Supinator longus. Extensores carpi 5 and 6 2 radiales. 7 Latissimus dorsi. Teres major. Triceps. Hxtensores carpi | radiales.. Extensors slightly. 8 and 9..Latissimus dorsi. Triceps. EHxtensors. Cubital.+ Flexor profundus. Flexor carpi ulnaris. Intrinsic muscles of hand. He lays down also the following laws :—{ - 1. Hach root furnishes branches to two systems, an anterior and a posterior. § . As the stimulus approaches the dorsal pairs, the contraction occurs in lower segments of the limb. 3. As the stimulus suanoe clues the dorsal pairs, the contractions pass from the radial to the ulnar border. He also adds— “Tt is a secondary law that the superficial layers are supplied before the deep.” Both these observers worked with monkeys, and Forgue’s laws are, with the exception of the first, identical with those which human dissections have produced for me. ‘That the details should exactly correspond is not to be expected in two different genera when indi- viduals of the same vary so widely. Hlectrical stimulation does not show the sensory supply. I have often tried to complete this account by dissecting the nerves upwards to the spinal cord. I have, however, never been able to rely on the results. The connective tissue permeating the nerve separates and protects the bundles of nerve fibres composing it, and renders their dissociation impossible. But as the nerve nears the intervertebral foramen this tissue very rapidly diminishes, and in the foramen the root consists of nerve bundles with hardly any connective tissue between them. The nerve bundles in the adult niight perhaps be separated even here from one another, but in the foetus, and these alone are for this purpose accessible to me, their minuteness and their softness have prevented any satisfactory dissection. * The radial here means the posterior cord of the plexus. + Ulnar. + Pp. 41-43. § This refers to the adult position. A truer view is to take the earliest observed position in the foetus. SMITHSONIAN INSTITUTION LIBRARIES “IVETE | 3 9088 01305 9993