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From May 2, 1889, to November 30, 1889. VOL. XLVI. Oe PE ov OF saith oan Ole@O7, SNe LONDON: HARRISON AND SONS, ST. MARTIN’S LANE, Printers i Ordinary to Her Majesty. MDCCCXC. LONDON? HARRISON AND SONS, PRINTERS IN ORDINARY TO HEK MAJESTY, ST. MARTIN’S LANE. )D CONTENTS. VOL. XLV. eit No. 280,— May 2, 1889. Note on the Effect produced by Conductors in the Neighbourhood of a Wire on the Rate of Propagation of Electrical Disturbances along it, with a Determination of this Rate. By J. J. Thomson, M.A., F.R.S., Cavendish Professor of Experimental Physics, Cambridge ..............0 : Researches in the Chemistry of Selenic Acid and other Selenium Com- pounds. By Sir Charles A. Cameron, M.D., F.R.C.S.1, V.P.LC., Professor of Chemistry and Hygiene, R.C.S.I., and John Macallan, fee Demonstrator of Chemistry, B.C.S2Lii.c:.ccciescciesessdasteteetonessssceroces On the Wave-length of the chief Fluting seen in the Spectrum of Man- Pee Gee NOFMAM, LOCK YOM EIS. cc.ccsosscosnecescoessceseotitcetaiousrencesesctasoes The Accurate Determination of Carbonic Acid and Moisture in Air. By J.S. Haldane, M.A., M.B., and M.S. Pembrey, Pell Exhibitioner of Christ Church, Oxford. (from the Physiological Laboratory, Oxford) On the Spectrum, Visible and Photographic, of the Great Nebula in Orion. ey Willian Huggins, D.C.L., LL.D., F.R.S., and Mrs. Huggins (Plate 1) .:. List of Presents O08 6 6 008000000 0008 OSTEO ES TOTO HESS OSES OTE HEOR OSES SORE TOET PEOD SOO DOOs SOOT OGEH COPS OGHG SESS VECSCIO May 9, 1889. On the Magnetic Rotation of the Plane of Polarisation of Light in doubly eee aG memo ees. Ey A NV 2 WANG. cinics, up a) where shat ome = GIL cen) )ie and re ie a yp dar | . in the outer conductor, qa. 2 dx up dy where vos “i LI, (en’r). From the continuity of ¢ at the surfaces r = a, r = b, we have AJj(qa) = BIJo(eq'a) coon DI) (eg"b) = BJo(eg’b) + C1p(eq'b) 4 Prof. J. J. Thomson. On the Effect produced by [May 2, From the continuity of H we get HJ (na) = FJo (ea) + GI,(e«a) +S xf mAST o(ega) 7 L1,(en'b) = FI,(ub) + GI, (ub) +~ =a emDI, (qb) j l From the continuity of F and G we get Lape J ABS, (ena) = “(FI y'(vea) + GIy! (ea) +2 (BIp (eg'a) n K “wp +CI,/( tease ae (qa), + eudatee <; UI, '(n'b) = ™R) (ecb) + GI,’ (ud) 4° (BJ,' (cq’b) + CJ («g'b)) — “1 Day (eq''b). 4 The magnetic force parallel to the surface of the wire is Ef 2 ae a dr dr/J’ and, since this is continuous, we have dt (na) = aE piece) 4 eee )) tT K pb \.. (4). 2-7/2 Qi A res Taare) = ae (BF,'(osb) + GIy (ucb)). Bb n K Eliminating E and L from equations (2) and (4), we get Dee a pee F (“> Jo(exa) J’ (raa) nea J, (+ea)To(ena) ) m—n?2 7, 2 Gi ee Jo (ena) (una) Ip (ewa) pn PY om, OS AT pas enya (5), ip pr « F (==5 aryl (a ya Jy (usb) Ty(end) ) » ‘(2 K 4G ( — Ti ecb My (rE) ae Ty/(esb)T(enb) mY” ig CORED OT Copy WL ae (6). “p bn 1889. | Conductors in the Neighbourhood of a Wire. i) EKliminating E and F from equations (35) and (4), we get ; , al 2 4-2 {Fy (ea) 4 Gy (ewal)} = ! ject w} m?—n? TEES ATH (ego) ea (BIg alee Oly (ala ye... (7), p UC ' 5 a ill mM? — K2 1 {¥Ip! (eed) + GIy! (ued) } 2a, i K m*—nN _ =f DI, (q')-“L (BI (:q'0) = Clg Caro) (8). We can substitute for B and © from equations (1) and get four equations from which we can eliminate F, G, A, and D; as, however, the result is lengthy, we shall only solve it for the particular case with which we are concerned, when qa, q’a, q’b, and q’’b, «a and xb, are allsmall. We get, substituting in the terms multiplied by v'—», the approximate values of the Bessel’s functions for small quantities of the variable —— Jo(eca) Jy (ena) meets tet) Jo (ua) Jo(ena) \ wn Kk —n'2 eee { oe LG) 1. Gas) iia) Pega (20) \ ue { BT Cen ena) LC ieh) pcaSe an pn K 1 V ve, (i—») m?* me — 1? — aJ, (ina) log =| \ K un 2 !2 a x { Some icy ihy ee” TC ub Gad) \ pn K In this equation the approximate values of the Bessel’s functions have been used only in the term multiplied by v’—». This equation simplifies very much, since «a and xb are very small, and therefore approximately Jo(cka) = 1, Jo (tka) = —tka, I)(tka) = log yika, and I,’(uka) = 1/ika. Making these substitutions, the above equation reduces to ee a pn 1 Jo(ma) pn V ¥,(nb) 1 alae) V m—rnady (ena) m*—n'?b I,'(n'b) J log (b/a) 6 Prof. J. J. Thomson. On the Effect produced by [May 2, (see also “Electrical Oscillations on Cylindrical Conductors,” ‘London Math. Soc. Proc.,’ vol. 17, p. 320), or, mee = Ey i+. ( = aa oP Tr) eat | m—nad (ma) m*—n’? bI,(un'b) The nature of the solution of this equation will depend upon the magnitudes of na and n’b. Case I. na and n'b both small. In this case Jo(ena)/Jg (ena) = —2/ma and = I) (en'b)/Tp'(en'b) = end log qyun'd. Making these substitutions, equation (9) becomes oP eg _ logy mb o Aine 10 an tR yee log (b/a) | 2Qma%p log (bja) J °° °°" Beas Since na is by hypothesis small, «/27a*p is large compared with unity, and unless log (b/a) is very great, it will be much the largest term inside the bracket, so that (10) may be written 2 1 Vv to Fae oe P vy ® Qra% log (2/2) ; ere ae Se v4rarp Te (b/a) J Cae: This represents a disturbance propagated with the velocity of (=) tos (la) f and dying away to l/e of its original value after traversing a distance 2 ; { a (v/a) } : yop This case, which is that of slowly alternating currents, was solved many years ago by Sir William Thomson. Case II. na large,n'b small. This is the case a rapidly alternating currents travelling along a wire which is surrounded by a substance whose conductivity is so small that 4 zp’pb?/o' is a small quantity. In this case, since Jy) (ima) = wJy(ena), equation (9) reduces to Pry he) ee eee (11). ve na log(b/a) log (b/a) J - 1889. ] Conductors in the Neighbourhood of a Wire. 7 Since na is large, the second term in the bracket will be small for wires made of non-magnetic metals ; so that for this case (11) reduces to Pf logan v log (b/a) / or, substituting for n’ the approximate value ae (= ) o Vv m? — = Vv Q he ae ple elderx'nb) | 7/4) 1s sproximately, me—- = — v log (b/a) log (b/a) or =Pix cece re) | 7 i } aly log (6?/a?) ESA los (o'/Azrp'pa*) J This represents a disturbance propagated with the velocity n/ y oy (racicieais) “pb?)\ log (b?/a”) and fading away to 1/e of its original value, after traversing a distance av \/ > a/ (lee 50 o ma) 7 1p y' a ae Am’ pa or if \ is the wave-length of the electrical vibration, the distance a disturbance travels before falling to 1/e of its original value is oe Arp! pa Thus in this case, even if v' equals v, that is, if Maxwell’s theory is correct, the rate of propagation of the disturbance along the wire will not be the same as that of electrodynamic action through air; and yet the conditions may be such as to allow a disturbance to pass over several wave-lengths before falling to 1/e of its original value. It will be noticed that the velocity of propagation does not depend on the specific resistance of the wire, and that it increases with the rapidity of the reversal, and that the rate at which the vibrations die away is independent of the resistance of the wire, and only varies slowly with the resistance of the outer conductor, since o' only enters in the form log o’. We can see the reason of this if we consider the amount of heat produced in the outer conductor. If 2 is the current parallel to the axis of z passing through a section of the wire, then, assuming in the investigation that v’ = », 8 Prof. J. J. Thomson. On the Effect produced by [May 2, a é = —P Hetne+ nt) | 2rrJ (nr )dr, (oy 0 — P elmervo R27 may o (una). o n The rate of production of heat in the wire is 9 a PY Bee2e(mne cal 2rr(Jo(ur))*dr oO 0 . | = 2 Bra?{I)2(ma) +I,2(ena) permet v9, oO Hence the ratio of the heat generated in the wire to o1?/za?, the heat which would be generated if the current were uniformly distributed, I pq? 190 (na) + Io? (ena) § 4 Fa or es Jo (na) Since when na is large Jy(ma) = (€%4// 2ena)(1+5 ), this ratio = 3na 4 2 The rate at which heat is generated in the outer conductor is 2g 0 Je er(mz+pt)] 2 | Qrrl,?(in'r)dr, ° b 2 ; PE L2arb?f 15'2(en'b) + 1y2(n'b) } ereme+ v0), Oo By equations (7) and (8) we have Ae AD) (Ae 77 ° so that TLbI,'(m'bjemte) 1 eh po mi—n'? p ¢ , = ae . 4, approximately. Thus the heat generated in the outer conductor © = AB 1a o ny? 12(@7b) since n’b is small, I)'('b) is large compared with I)(m’b), and n’? is approximately A rpu'ip|c’. 1889.] Conductors in the Neighbourhood of a Wire. a Thus the rate at which heat is generated in the outer conductor is approximately pipe’, and is therefore approximately independent of the resistances of the wire and of the outer conductor, and large compared with the heat developed in the wire. The case of an iron wire would differ from that investigated in the case when though wa is large, u/na is also large; in this case equation (9) becomes approximately which represents a vibration travelling with a smaller velocity than that of the electrodynamic action through the dielectric, and dying away to l/e of its original value after traversing a space comparable with a wave-length. When the rate of alternation of the currents gets sufficiently rapid, n’b gets large, and «/na small, and we get Case III. na and n’b both large. In this case, since Jy (ena) = WJ (ma) and I)/(en'b) = —el)(n'b) and equation (9) reduces to 5 pee(S+ alert log (b/a) cant = {1+ Tem Gas) +A beara: mah flare | a/(S)t4/() heal: This represents a vibration travelling with the velocity v./(v/v'), and dying away to 1/e of its original value after traversing a distance SESS B/E} POI From this equation we see that if c/a? is very much greater than a’ /b*, the decay of the disturbanve will be due chiefly to the resistance of the wire, but if, on the other hand, o'/b? is very much greater than o/a”, the decay will be due chiefly to the resistance of the outer con- ductor. This case includes that of a wire surrounded by a metal tube, the space between the tube and the wire being occupied by any dielectric, in this case the electrical conditions are perfectly definite, and we see that the velocity of propagation along the wire will be v/(v/v'), where v is the velocity of propagation of the electrodynamic action through the dielectric. Thus if v’ = v, as in Maxwell’s theory, the velocity along the wire will be the same as that through the 10 Prof. J.J. Thomson. On the Liffect produced by [May 2, dielectric, but it will not be so unless this condition is fulfilled. Thus this case would afford a definite means of testing whether or not Maxwell’s theory is true. The taickness of the outer tube would be immaterial, as with these very rapid vibrations the currents are entirely confined to the inner skin of the tube. By comparing the results for this case with those of Case II, we see that if the rate at which the electrical disturbances die away depends on the conductivity of the wire, the velocity of propagation through the wire must be the same as that through the dielectric if Maxwell’s theory is true. - The preceding equations can be modified so as to include the case when the outer conductor is replaced by another dielectric; all that we have to do is in equation (9) 10 replace n' by «’, where «9 = mi — (p/p), v, being the velocity of propagation through the outer dielectric. In this case equation (9) becomes Jo(ena) ek’ nee’) \ oe oe log (bja)* a If both «’b and na are large, the velocity is the same as before, viz., v/(v/v'). If na is large and «’b small, the equation becomes approximately eee ae we LU mP—n? Jy (ema) m?—«,? Ip (ced) p” 4 Ty (ex'b) ye v —_ mn? — = «KP v log (b/a) v? or substituting for Ip(u«’b) we get nb} log (A/y«'b) ot _ — oo y' ' loz (bia) a oe log (b/a) Thus the velocity of propagation is 1 cue log (1/y'b) % a v" log (bja) * Tig en log (b/a) As it has been shown above that if the rate at which the vibrations decay depends upon the nature of the wire, the rate of propagation of the disturbance along the wire will be v./(»/v'), I thought it would be of interest to determine the rate of propagation in this case, in order to see whether the velocity would still differ as much as in Hertz’s experiments from that of the propagation of the electro- dynamic action through air. 1889.] Conductors in the Neighbourhood of a Wire. Al The method used is shown in fig. 1. AB, CD is the action of a vibrator (shown in elevation in fig. 2) of the same shape and size as the one used by Hertz in the experiments described in Wiede- mann’s ‘ Annalen,’ vol. 34, p. 553, AB, CD being squares of tin-plate, 40 em. square. BH, EF wires, each 30 cm. long, terminating in the brightly polished balls E and F, these balls being separated by an air space of 30r4mm. The terminals of the induction coil are fastened to BH, CF respectively. lL, N are pieces of tin-plate placed in front of AB and CD, having insulated wires about 25 metres long fastened to them, the ends M and O being covered with sealing-wax. The resonator (fig. 3) is, as in Hertz’s experiments, a ring of wire about 70 cm. in diameter, terminating in two balls, the distance between which can be accurately adjusted by means of a screw. The way in which the resonator was used was different from Hertz’s method. ‘l'wo wires of equal length covered with gutta-percha and 12 LEffect'of Conductors in Neighbourhood of a Wire. [May 2, surrounded by tin-foil, connected at both ends with the earth, were fastened close to the balls of the resonator; the other extremities of these wires could move aiong the wires LM, NO respectively. When the coil was working, sparks passed between the balls of the reso- nator, and it was found that the intensity of these sparks depended on the position of the points P and Q, to which the extremities of the wires of the resonator were attached. The experiments made to determine the velocity through the wire were as follows: the end Q of one of the wires of the resonator was placed at O, the end of the wire NO and the extremity P of the other wire moved along LM until the sparks in the resonator were as faint as possible; the dis- tance P,M, when this was the case, was about 5 metres. We may conclude that in this position the points P, and O are nearly at the same potential. The end of the other wire was then moved along NO until the sparks were again as faint as possible; the position Q,, when this was the case, was such that Q,O was between 10 and 10°25 metres. Since the sparks are again a minimum, we may conclude that P, and Q) are again at nearly the same potential, hence the potentials at Q, and O must be very nearly equal, but when this is the case, Q,O must be very nearly a wave-length; the wave-length in the wire LM was found in a similar way to be also about 10 metres. Hence the wave- length of the electrical vibration in the wire must in this case be about 10 metres, but Hertz has shown by the interference of the direct electrical waves, and those reflected from a large metal reflector, that the wave-length of the action propagated through the air from this vibrator is also about 10 metres, and the length of the wave must be approximately the same in our experiments as the resonator which responded to the vibrations was of the same dimensions. So that in this case the velocity of propagation through the wire is the same as that through the air. Since the sparks between the balis of the resonator never actually vanish, the determination of the places where they are as faint as possible is a matter of judgment, and thus the method is not capable of any very great accuracy. I found, however, on comparing my results with those of another observer, Mr. H. Everett, that the two sets agreed within about 2 feet in 10 metres. The rate at which the disturbances die away was determined by a preliminary experiment. In this only one wire was used, and this was carried over the laboratory until when the resonator was used in the way described by Hertz no sparks passed between the balls; the length of wire necessary for this was more than twice as great for copper as for German silver wire of the same diameter. Thus the rate of decay depends on the material of which the wire is made, and, therefore, by the above investigation the velocity through the wire is v/(r|v'). 1889.] On Selenic Acid and other Selenium Compounds. 13 [On repeating the experiments after the Haster Vacation, an effect was observed which may explain the difference between the value of the wave-length along the wire found in the above experiments and those of Hertz. It happened that the plates after the vacation were placed further from the wall than they had been before, and it was found that the wave-length was much less, being now between seven and eight metres; on moving the plates nearer the wall the wave- length increased, the increase being evidently due to the increase in the capacity of the plate produced by the proximity of the wall. Thus if the distance of the plates from the walls was different in the determination of the wave-length along the wire from what it was in the determination of the wave-length through air, the wave- lengths would not be equal even if the velocity of propagation were the same. I endeavoured to determine the wave-length in air by measuring the distance between the nodes after reflection from a large metal screen, but could not succeed in fixing the position of the nodes with sufficient definiteness to determine the wave- length with any accuracy. The fact, however, that I got a wave-length in the wire the same as that obtained by Hertz through air, is sufficient to show that it is not necessary to suppose that the velocities through the wire and air are different, but that the difference in Hertz’s results may have been due to a change in the position of the vibrator rela- tively to the walls of the room.—May 15. | IT. «‘ Researches in the Chemistry of Selenic Acid and other Selenium Compounds.” By Sir CHARLES A. Cameron, M.D., F.R.C.S.L, V.P.L.C., Professor of Chemistry and Hygiene, EAC Sul, aad JouN MAcALLAN, F.I.C., Demonstrator of Chemistry, R.C.S.1. Communicated by Sir Henry Roscox, F.R.S. Received April 6, 1839. Although selenic acid was prepared by Mitscherlich so far back as the year 1827, few chemists appear to have studied its properties. This want of interest in selenic acid is rather surprising, seeing that it possesses so close a relationship to sulphuric acid, which is so important a compound. Finding the chemistry of selenic acid so meagre, we resolved to make an investigation of this body, with the view of bringing, so far as we could, its chemistry abreast with that of sulphuric acid, and also in the hope that its study would yield results which might throw additional light on the relations of the latter acid. The following pages contain the results at which we have arrived. : 14 Prof. Sir C. A. Cameron and Mr. J. Macallan. [May 2, Preparation of Anhydrous Selenic Acid, H,SeO,. Selenic acid has hitherto heen known only in a dilute form. When heated to about 260° C. it commences to decompose into sele- nium dioxide, oxygen, and water, which prevents any further concen- tration. Berzelius describes it as containing, when of greatest strength, 4 per cent. of water ; but since his time it has been obtained in a more concentrated condition by Fabian, who, by evaporating the acid to a temperature of 265°, found it to have a strength of 94°9 per cent., and by placing this acid, while still hot, under the receiver of an air-pump, increased. its strength to 97°4 per cent. Sulphuric acid, as is well known, has not been obtained in a perfectly anhydrous state by ebullition—although in its case decomposition does not occur ; for when it reaches a strength of about 98°66 per cent. it boils without further change. When, however, an acid of this strength is sur- rounded with a freezing mixture, the anhydrous acid, H,SQ,, crystal- lises out. An attempt was first made to obtain anhydrous selenic acid by similar means. Great care was taken to obtain an acid of pure quality. An examination was specially made for nitric, sulphuric, hydrochloric, and hydrobromic acids. Selenious acid, when present, was removed by diluting with about 30 parts of water, saturating with hydrogen sulphide in the cold, filtering and concentrating on the water-bath. The acid thus treated was then examined for sulphuric acid and found to contain none. A portion of the acid, when ignited, left a residue equivalent to 0:07 per cent. of the anhydrous acid present in the specimen used in the experiments ; this was ascertained to consist of neutral sodium selenate, and was, of course, derived from an acid salt, of which it was necessary to take account in the suc- ceeding experiments. Some of this acid was gradually heated until the temperature rose to 250°. It was next poured into an open dish, and allowed to cool slowly over sulphuric acid, under an exhausted receiver. Thestrength was then taken with seminormal soda solution, which was specially prepared for those experiments, by making a solution in water of pure caustic hydrate prepared from sodium, and bringing it carefully to the required strength: 11°81 cubic centimetres of soda solution were required for neutralisation by 04371 gram of acid, equivalent to 97°75 per cent. of selenic acid, being thus a little stronger than that obtained by Fabian in a similar way. The acid thus concentrated was then poured into a stout wide glass tube, having one end closed, and the open end fitted with an india- rubber cork, through which passes a glass rod for the purpose of keeping the viscous liquid stirred, and a capillary tube for admis- sion of air, in order to expose the acid to the full atmospheric pressure. The necessity for those precautions in the case of sulphuric acid has 1889.] On Selenic Acid and other Selenium Compounds. 15 already been fully pointed out by Marignac (‘Annales de Chimie,’ vol. 39, 1853, p. 184), the discordant results arrived at by various observers being probably due to the different conditions under which they worked. The latter precaution is particularly necessary, as we have observed that sulphuric acid occupies less volume in the solid than in the liquid state. The temperature of the acid was then gradually lowered. Its viscosity increased as it became colder, until at a temperature of —51-5° C. it was as thick as soft pitch—the tube might be inverted without the acid flowing, and a glass rod could be moved in it only with great difficulty. Still it did not freeze, until after vigorous stirring maintained for a couple of minutes, a crystal appeared, and then the entire mass almost instantaneously crystallised, the tem- perature rapidly rising. When removed to a warm room, the crystals were rather permanent, and when nearly melted, recrystallisation could easily be induced by exposure to moderate cold so long as any erystal remained, showing that previous to freezing the acid had been in a more or less superfused condition. It was found to be impossible, however, to separate the crystals by draining the liquid portion, as the latter was so viscous that it carried the crystals with it. Under the microscope they were seen to be long prisms. An attempt was next made to examine the conditions under which selenic acid becomes strengthened in a vacuum, with -the object of obtaining, if possible, a more concentrated acid; and the following arrangement was made for the purpose:—The glass receiver of an air-pump was fitted tightly at its neck with an india-rubber cork, through which passed a bent tube, connected horizontally with another and wider tube containing solid potash. This was connected with a wide (J-tube, filled with pieces of potash about half an inch long, and kept cool by immersion in a beaker of water. Connexion was then made with a small stout flask containing the selenic acid, and varying in size from 100 to 250 cubic centimetres as required, The potash-tube next the receiver was intended for the purpose of pre- venting acid fumes from injuring the air-pump, and for the same reason a vessel of potash was placed within the receiver. The air-pump employed gave a very good vacuum; when all the connexions were made, and the pump exhausted, there was often scarcely any appre- ciable difference in the levels of the columns of mercury in the gauge. For temperatures up to 100° the flask containing the acid was heated in a beaker of water; for higher temperatures oil was used. Soon after commencing the experiments it was found necessary to make an arrangement for the purpose of stirring up the viscous acid and exposing fresh surfaces to the vacuum, and the following plan was devised :—A test-tube, which fitted easily the neck of the flask, was shortened by removing evenly a portion of the open end. It was a ee ee eee Per aes ge 16 Prof. Sir C. A. Cameron and Mr. J. Macallan. [May 2, then inverted and pushed down into the flask, so that when the open end was below the surface of the acid, the closed end extended suffi- ciently far into the neck of the flask to prevent the tube from being thrown down by the ebullition of the liquid. The vapour given off from the acid within the tube became gradually expanded as the temperature rose, and passed in a stream of bubbles through the acid, keeping it well agitated. The tube also served the purpose of pre- venting splashing from the boiling acid up into the neck of the small flask. Some selenic acid, which had been previously partially concentrated, was kept in an open dish on the water-bath forfour hours and its strength . then determined: 0°6364 gram required for neutralisation 14°72 c.c. of seminormal soda solution, equivalent to 83°68 per cent. of selenic acid—a strength intermediate between a monohydrate and a dihydrate. The acid thus obtained at 100°, under the ordinary pressure of the atmosphere, was stronger than that obtained by Graham from dilute sulphuric acid by heating it to the same temperature in a vacuum until it ceased to lose weight—the dihydrate, H,SO,,2H,O, remaining showing the greater affinity for water possessed by the latter acid. Selenic acid, concentrated as above described, was poured into the flask previously referred to, and gradually heated. Weak selenic acid commenced to pass over at 56°, evidenced by the potash liquefying and effervescing, owing to the presence of potassium carbonate which it contained, being the ordinary commercial potash. It was then heated slowly up to 100°, kept at that temperature so long as any acid distilled over, and the strength of the residue taken: 0°9432 gram re- quired for neutralisation 24°10 ¢.c. of seminormal soda solution, equivalent to 92°44 per cent. of selenic acid. Subsequent to this experiment, acids heated on various occasions to 100° were found to have the following percentages of anhydrous selenic acid :—92°03, 92°08, 93°28, and 93°70; the different results being found due to the varying conditions of the experiments, such as the length of time of heating, the quantity of potash, and its proximity to the acid, the amount of the latter, and the size of the flask containing it. The acid which had been heated to 100°, was next heated to 150°. At the latter temperature the more or less dilute acid distilling over appeared in the form of dense white fumes resembling those of sul- phuric acid. 0°6898 gram of the residue left nentralised 18°42 c.c. of seminormal soda solution, equivalent to 96°58 per cent. of selenic acid. It was again heated to 150°, and kept at that temperature so long as any acid distilled over: 0'417 gram of the residue left neutralised 11°21 c.c. of seminormal soda, equivalent to 97°25 per cent. of selenic acid. A fresh portion of acid was heated to 155° and kept for some time at that temperature : 0°3045 gram of the residue neutralised 21°72 c.c. 1889.] On Selenic Acid and other Selenium Compounds. 17 of seminormal soda, showing 97°67 per cent. of selenic acid. It was next heated to 162°, and the strength of the residue taken: 0°7291 gram neutralised 19°72 c.c. of seminormal soda, equivalent to 97°85 per cent. of selenic acid. The same acid was then heated to 216°, and the residue obtained was allowed to remain in the flask during the night. In the morning it was found to be frozen into a crystalline mass so hard that it was necessary to use a steel chisel 1n order to remove portions for examina- tion. When dissolved in water and tested it was found to contain some selenium dioxide. Trials were then made to ascertain if a lower temperature would produce a similar result without decomposition of the acid; 180° was found to be sufficient for the purpose, and the fol- lowing course was finally adopted:—The acid, which had been con- centrated on the water-bath as far as possible, was heated gradually im the flask to 100°, and kept at that temperature so long as any acid distilled over, the greater part of the water being thus removed. The U-tube was then disconnected, emptied, and refilled with stick potash. The flask was next heated gradually to 180°, kept at that temperature until no more acid distilled over, and then immediately cooled. A still better arrangement was to use so little acid that it was unnecessary to change the potash. The acid was heated gradu- ally and continuously up to 180°, allowing bubbles to pass slowly through it, as before described. When 180° was reached the potash was watched, and as soon as it ceased to be acted upon the flask was immediately cooled. An hour or less was generally found sufficient time for a small quantity of acid. A specimen obtained in this way was found, when examined, to be very free from selenium dioxide, a little of it diluted with water and saturated with hydrogen sulphide, merely giving a faint yellow colora- tion without any precipitate. Another portion was acidified with hydrochloric acid and barium chloride added; on boiling the filtrate with stannous chloride it only became darkened in colour without any precipitation of selenium. 06725 gram was taken to estimate the strength: 18°54 c.c. of seminormal soda were required for neutralisa- tion, equivalent to 99°73 per cent. of selenic acid. 0°724 gram of another acid, prepared in a similar way, but which contained rather more selenium dioxide than the last, required for neutralisation 19°94 ¢.c. of seminormal soda, equivalent to 99°64 per cent. of sele- nic acid. A portion of a third acid, weighing 0°329 gram, was dis- solved in water, barium chloride added, and also hydrochloric acid in order to prevent any selenious acid from precipitating. The resulting barinm selenate weighed 0°6337 gram, equivaient to 99°75 per ceut. of selenic acid. As has been already mentioned, the acid employed contained an acid potassium selenate equivalent to 0°07 per cent. of neutral sodium selenate found. Taking this. into account, and calcu- VOL. XLVI. C 18 Prof. Sir C. A. Cameron and Mr. J. Macallan, [May 2, lating on the acid with the sodium selenate deducted, the three results become respectively— I. TI. alee 99:80 99-71 99°77 The difference between the above results and 100 per cent. must be ascribed partly to the very hygroscopic character of the acid in the anhydrous condition, and consequent slight absorption of moisture during the process of weighing. It is necessary to observe, however, that in making the above caleulations, and all through in this paper, 78°87 has been adopted as the atomic weight of selenium, the number given by Meyer and Seubert in their ‘ Recalculations of the Atomic Weights.’ If 78°80, the number given in Clarke’s ‘ Recalculations,’ be taken, the three results become— i i dU aoe fotate 99°75 99:66 99-72 Petersson and Hkman state that the results of a great many analyses show that the most probable atomic weight of selenium is 79°08 (‘Berichte Deutsch. Chem. Gesell.,’ vol. 9, p. 1210). If this number be taken, the above percentages become respectively — I. | II. TIT. 99°94, 99°85: 99°91 The results arrived at from the foregoing experiments lead to the conclusion that at 180° in a vacuum,.selenic acid parts with all com- bined water, and remains as the anhydrous acid, H.SeO,. It may be well here to summarise the precautions necessary to be taken in preparing the anhydrous acid, so far as we have ascertained them. They are briefly as follows:—To use for the purpose an acid as pure as possible, to have a thoroughly good vacuum, to avoid too high or prolonged heating, and to keep a sufficient quantity of solid potash in close proximity to the acid all .through—which may’ be arranged by using a small flask, and having the tube leading from it short and wide. Properties of Anhydrous Selenie Acid. Anhydrous selenic acid is a white crystalline solid melting at 58° to a colourless oily-looking liquid. When thoroughly melted it remains in a, superfused state, and usually requires to be cooled to about 5° with constant stirring before it again freezes. The temperature then rises rapidly to 58°, and remains stationary until complete solidifi- eation of the acid has taken place. When at rest it can be cooled lower than 5° without freezing, and it will remain in a stoppered bottle for months, and during frosty weather, in a liquid condition: i a ] 889. | On Selenic Acid and other Selenium Compounds. 19 It instantly solidifies at any temperature below 58° if a crystal of the solid acid be dropped into it, and it freezes sometimes at ordinary temperatures when rubbed with a sharp piece of glass or with the point of a pipette. It thus exhibits the property of superfusion in a remarkable degree, and to a greater extent than anhydrous sulphuric acid, which, according to Marignac, possesses eminently the property of superfusion (‘Annales de Chimie,’ vol. 39, 1853, p. 184). Its melting point, 58°, is higher than that of anhydrous sulphuric acid, 10°5°, but lower than that of telluric acid, which may be heated nearly to redness without melting. Anhydrous selenic acid erystallises in long interlacing hexagonal prisms. Jn animpure condition from the presence of selenium dioxide and other substances, its melting point is lowered, and under those circumstances it is sometimes deposited slowly and spontaneously in the form of double pyramids, many of them intersecting in pairs. Although much has been written upon the freezing-point of sul- phuric acid, but little information appears to be published regarding its crystalline form. It is stated, however, in Graham’s ‘ Chemistry,’ vol. 1, that the most concentrated acid, when frozen, often yields regular six-sided prisms of a tabular form. Chaptal describes the erystals as being six-sided prisms terminating in pyramids with six faces. Both accounts agree in placing them inthe hexagonal system. In order to see if the appearance of the crystals agreed with either of the above descriptions, some sulphuric acid was strengthened by boiling for some time, and then cooled down until it froze. The crystals obtained were found to be long six-sided prisms ending in pyramids, as described by Chaptal, and no prisms of a tabular form were observed. It is thus interesting to find that both anhydrous sulphuric and selenic acid crystallise in prisms in the hexagonal system, but it remains doubtful whether or not they are strictly iso- morphous, Selenic acid in the anhydrous condition possesses a powerful affinity for water, absorbing it quickly from the atmosphere. Their combina- tion is attended with contraction and considerable evolution of heat, but less so than in the case of water and sulphuric acid. Like the latter, it disintegrates and blackens many organic substances, such as cork, india-rubber, &c. From others it withdraws the elements of water; thus, alcohol heated with it yields ethylene, and glycerine, acrolein. On cellulose it has an action similar to that of strong sulphuric acid, paper being converted by it into a tough parchment- like substance. For this reason it should not be filtered through filtering paper, except when cold and very dilute. Iodine dissolves in the superfused acid when heated, forming a brown-coloured solu- tion. It is acted on violently by pentachloride of phosphorus in the cold—a reaction which we are at present examining, Oxychloride of o 2 20 Prof. Sir C. A. Cameron and Mr. J. Macallan. [May 2, phosphorus also acts strongly upon it when warmed slightly, the reaction being attended with copious evolution of gas and reduction apparently to lower compounds. Selenium dioxide dissolves in it when heated, but the greater part crystallises out again in the cold. There is no evidence of formation in this way of an acid analogous to hyposulphuric acid, H,S,0,. The crystals of the solid acid dissolve in strong sulphuric acid, and also in Nordhausen acid. The specific gravity of the superfused acid, taken with a Sprengel tube at 15°, was found to be 26083. The specific gravity of the solid acid was taken in pure benzene of specific gravity 0°8851, which is not acted upon by it in the cold, and in which it is insoluble. As might be expected, it at once blackens commercial benzene. Its specific gravity, taken in this way, proved to be 2°9508 at 15°. It thus resembles anhydrous sulphuric acid in being denser in the solid than in the liquid state. The specific gravity of the liquid acid is much greater than that of anhydrous sulphuric acid, 1°8384; and on the other hand the specific gravity of the solid acid is less than that of anhydrous telluric acid, which is stated by F. W. Clark to be 3°425 at 188° (‘American Journal,’ vol. 14, 1877, p. 281; vol. 16, 1878, p. 401). Monohydrated Selenic Acid: tts Preparation and Properties. Some selenic acid, which had been concentrated on the water-bath, was heated for some time in a vacuum at 100°, and its strength de- termined: 0°7858 gram neutralised 20°00 c.c. of seminormal soda solution, equivalent to 92°08 per cent. of selenic acid. The acid so prepared was diluted with sufficient water to reduce its strength to 88°96 per cent., corresponding to a monohydrated acid, H,SeO,,H,0. It was then poured into a wide tube and its temperature gradually lowered, the same precautions being taken as to stirring and admissien of air as were adopted previously in freezing out the anhydrous acid. Its viscosity increased with the fall in temperature, until at —32° it froze into a mass of crystals. These were melted and re-crystallised several times, and the resulting product examined. A few of the crystals obtained were long needles, but most of them were large and broad, having a general aspect to which the term “elacial” might be applied appropriately, but differing in appearance under the microscope from those of glacial sulphuric acid. Its melting point was found to be 25°. Like glacial sulphuric acid, and also like anhydrous sulphuric and anhydrous selenic acid, when once melted it exhibits the property of superfusion, and to as great an extent as the last-mentioned acid, since it may be cooled to more than 90° below its melting point, with constant stirring, before it again freezes. When frozen it remains quite solid at ordinary temperatures; but if the bottle containing it be removed to a warm 1889.] On Selenic Acid and other Selenium Compounds. 21 room, or much handled, it commences to melt. Like the anhydrous acid, it at once freezes at any temperature below its melting point when a crystal of the same acid is dropped into it. It resembles the anhydrous acid also in having a melting point much higher than sulphuric acid of the same strength, that of glacial sulphuric acid — being given by Pierre and Puchot as 7°5°, by Jacquelin as 8°, and by Marignac as 85°. It resembles the latter acid in having a melting point lower than its anhydrous acid, but while the difference is about 2°5° in the case of sulphuric acid, the melting points of the two selenic acids differ by 33°. In the following table their melting points are compared :— Anhydrous. Monohydrated. Sulphate acide, 6 « 10°5° 8° PeIeMIC ACID. os esos 58°0 » 25 It may be well to state here that 0° is given erroneously in several chemical works as the melting point of anhydrous sulphuric acid. Marignac, the most recent investigator who has studied the subject, assigns the temperature 10°5° as its true melting point. _ The superfused monohydrated selenic acid has a specific gravity of 92-3557 at 15°. That of the solid acid was taken in pure benzene, in which it is insoluble, and on which it is without action at ordinary temperatures, even after standing all night. A portion of the liquid acid was poured into the specific gravity bottle, a crystal dropped into it, and the acid, having become firm and cold, weighed, and the bottle filled with benzene. The specific gravity was found to be 2°6273 at 15°. It thus resembles the anhydrous acid in being denser in the solid than in the liquid state; while melting, the crystals sink rapidly in the liquid portion. This acid commences to boil at 205°, the acid vapour given off being at first very weak, but it increases in strength with the rise in temperature. A more dilute acid gives off water only until the tem- perature reaches 205°. Dilute sulphuric acid is stated to behave in a similar manner, giving off nothing but water until the boiling point reaches 205—210°, at which temperature it has the strength of the monohydrated acid, H,SO,,H,0. The ease with which an acid of this strength can be obtained and crystallised, supplies a means of separating impurities from selenic acid, all that is necessary to do being to boil a dilute acid until the temperature reaches 205°, cool, and drop in a crystal from an acid already frozen ; the resulting crystals can then be melted and recrys- tallised. It may be well here to draw attention to the conflicting statements which are made in various works regarding the crystalline form of glacial sulphuric acid. Watts’s ‘Dictionary,’ vol. 5, and Richter’s 22 Prof. Sir C. A. Cameron and Mr. J. Macallan. [May 2; ; Inorganic Chemistry, state that it crystallises in six-sided prisms ; but in several chemical works the crystals are described as rhombic prisms, while Pelouze and Fremy mention that it forms large trans- _ parent crystals which are rhomboidal prisms. The crystalline form is thus referred to three different systems. The first description is probably copied by mistake from that of the anhydrous acid. The most recent investigators of the point are Jacquelain (‘ Annales de Chimie,’ vol. 30, 1850, p. 343), and Pierre and Puchot (‘ Annales de Chimie,’ vol. 2, 1874, p. 164). The latter say that the crystalline form appeared to them to be the oblique rhomboidal prism, and that they obtained the crystals, some very large, others thin and very long. Jacquelain describes them as being oblique prisms very in- clined and very large; and states that he obtained them, by a rather slow crystallisation, distinctly oblique and very short, and by a quick crystallisation, in very long oblique prisms. | The Existence of higher Hydrates. A portion of dilute selenic acid was concentrated on the water-bath and its strength taken: 0°8603 gram neutralised 19°48 c.c. of semi- normal soda solution, equivalent to 81°92 per cent. of selenic acid. The acid so prepared was diluted with sufficient water to reduce its strength to 80°11 per cent., corresponding to a dihydrated acid, H,SeO,,2H,O, and its temperature then gradually lowered. When kept at —51° for some time it became as viscous as thick syrup, but did not freeze. The last acid was then diluted to a strength of 57°32 per cent. of selenic acid, corresponding to a hydrate of the composition H,SeO0,,6H,O. The acid thus prepared did not freeze when kept at —49°, and was quite liquid at that temperature. Although no proof of the existence of higher hydrates than the monohydrated acid was obtained in the foregoing experiments, it appears probable that a dihydrated acid, and perhaps other hydrates, are capable of existing. Sulphuric and telluric acid have both been obtained as dihydrates. Considerable heat is evolved when mono- hydrated selenic acid is mixed with suflicient water to reduce its strength to that of a dihydrated acid. When the latter is further diluted, there is an additional slight evolution of heat. It is probable that as the freezing point of monohydrated selenic acid is consider- ably below that of the anhydrous acid, so the freezing point of a dihydrated acid is still lower. In order to get an approximate idea of the amount of water which anhydrous seienic acid absorbs, a portion weighing 0°9776 gram was placed on a watch-glass protected from dust, but with free access of air. After twenty-four hours the acid weighed 2°0284 grams, showing an absorption in that time of between 8 and 9 molecules of water by 1 molecule of anhydrous acid. Another portion weighing 0°4416 gram was exposed until it ceased to: 1889.] On Selenic Acid and other Selenium Compounds. 23 absorb water; the acid then weighed 1°8152 grams, indicating absorp- tion of rather more than 25 molecules of water by 1 molecule of anhydrous acid. Having arrived at this stage, it commenced to give off a little of the water which it had previously taken up, but the weather became warmer just at this period, so that probably the above amount does not represent the total absorption of which the acid is capable. It is less, however, than the amount taken up by the molecule of sulphuric acid, which is variously paced at from 80 to 100 molecules of water. The Conditions which affect the Freezing Points of Selenic Acid and Sulphuric Acid. It has long been recognised that in order to determine the melting point of a chemical compound with accuracy it is necessary, by crys- tallisation or other means, to obtain it in a pure condition. The necessity for such a precaution is well shown in the case of the oxides and acids of sulphur and selenium. An example taken from the former class of bodies is furnished by sulphuric anhydride. Up toa comparatively recent date great diversity of opinion prevailed regarding the melting point of this substance until Weber showed that, as hitherto examined, it had usually contained a minute quantity of water, which had the effect of altering its melting point, crystal- line form, and other properties. Sulphuric acid supplies another instance of a similar effect. Its melting point in the anhydrous condition is 10°5°, while that of the monohydrated acid is 8°; yet commercial sulphuric acid has usually been found to remain liquid above a temperature of —30° or —40°, and it is stated in some chemical works that by addition of a little water to the commercial acid its freezing point has been lowered to —80° ; but it is not men- tioned whether or not this occurred in closed or open vessels. A still more striking example of the influence of want of purity upon the melting poimt is afforded by selenic scid. In the anhydrous state it melts at 58°, but a slightly dilute acid, as we have found, was frozen only when a temperature of —51°5° was reached, showing a fall of 109°5°, and probably further dilution would be attended by a still greater reduction of the freezing point. The depression of the freezing point can be due only partly to superfusion since the super- fused anhydrous acid freezes at about 5°. The monohydrate present in the dilute acid therefore exerts an influence in lowering the freezing point of the anhydrous acid, and also its melting point. An analogous action probably occurs in the case of some metallic salts, which, although without apparent chemical action upon each other, have a lower fusing point when mixed than when heated separately. A consideration of the foregoing facts leads to the conclusion that dilute selene acid having a strength greater than 88°96 per cent. contains the ON a ee ‘e - a ti ye 24 Prof, Sir C. A. Cameron and Mr. J. Macalian. [May 2, anhydrous and also the monohydrated acid existing in a superfused state, and exerting a solvent action upon each other. In the case of sulphuric acid a similar action evidently occurs. The effects of agitation and of alteration of pressure upon the freezing points of the above acids have already been referred to. The Method used in Freezing Selenic Acid. Liquefied sulphur dioxide was poured into a thick glass tumbler, holding about half a litre, fitting into a somewhat wider and deeper cylindrical gas jar, which served to retain any of the dioxide splashed . from the interior vessel, the whole being imbedded deeply in a con- siderable quantity of cotton wadding contained in a wooden box. A rapid current of air was driven through the sulphur dioxide, the air — being first dried by means of sulphuric acid and then cooled by pass- ing through a leaden worm surrounded by a mixture of salt and pounded ice, or less effectively, sodium sulphate and hydrochloric acid. Any desired degree of cold within limits could easily be main- tained by regulating the current. When the outside air was at 0°, about half a kilogram of sulphur dioxide was found sufficient for more than two hours’ use, evaporation taking place but slowly at the low temperature reached, the latter, measured with an alcohol ther- mometer, falling below —50° C. In warmer weather nearly as low a temperature was obtainable, but consumption of the sulphur dioxide was much more rapid. No arrangement of freezing mixtures produced nearly so low degrees of cold as were attained in the above manner. Doubtless when a supply of dry snow is available, and the weather is very cold, so that the apparatus and materials used can be well cooled down previous to mixing, a very low temperature is obtainable by ordinary freezing mixtures, but those conditions are not often to be met with in these climates. On the other hand, sulphur dioxide is cheap and easily procurable, and convenient when used in the manner described. The Specific Gravities of the Higher Strengths of Selenic Acid. The specific gravities of selenic acid for the higher strengths, taken in the liquid state at 15°, are given in the foliowing table. The most concentrated acid, of $9°73* per cent. strength, has been referred to under the head of the preparation of the anhydrous acid ; . its specific gravity, 2°6083, was taken while in the superfused con- dition. The next acids down to 94°74 per cent. were obtained by diluting that of 99°73 per cent. The acid having a strength of 93°70 per cent. was obtained by heating dilute acid in a vacuum at * 99°73 per cent. of selenic acid, acid sodium selenate, equivalent to 0°07 per cent. of neutral sodium selenate, and 0°20 per cent. of water (Se being = 78 87). 1889.] On Selenic Acid and other Selenium Compounds. 25 100°, and it supplied the following strengths, down to 82°52 per cent. by progressive dilution. That of 81:73 per cent. was prepared by concentration on the water-bath, and the remaining four by dilution of the latter. Neither the acid heated in a vacuum, nor that which was kept on the water-bath, contained any trace of selenious acid. Table I. Percentage of anhydrous selenic acid. Specific gravity. 99°73 2°6083 99°08 2°5993 98°68 2°5901 98°16 2°5790 97°37 2°5676 96°97 2°5099 96°16 2°5424 94:7 4: 2°51U5 93°70 2°4852 92°83 2°4534 91:59 2°4218 90-06 2°3863 89°20 2°3642 88°55 2°3402 87°34 2°3158 85°60 2°2946 85°67 22712 84°59 2°2463 83°82 2°2196 82°52 2°1878 81°73 2°1694: 80°86 2°1438 79°99 271213 79-06 2°0940 73°43 19609 Table II is calculated from Table I, and gives specific gravities interpolated from equal increments of strength. It will, perhaps, be found most convenient for purposes of calculation, and for showing the relation of the rate of increase of specific gravity to that of the strength. 26 Prof. Sir C. A. Cameron and Mr. J. Macallan. [May 2, Table II. Percentage of anhydrous selenic acid. Specific gravity. 99°73 2°6083 99-50 2°6051 99-00 2°5975 98°50 2°5863 98-00 2°5767 97°50 -2°5695 97°00 2°5601 96°00 2°5388 95°00 2°5163 94-00 2°4925 93°00 2°4.596 92°00 24322 91-00 2°4081 90°00 2°3848 89-00 2°3568 88°00 2°3291 87°00 2°3061 86°00 2°2795 85°00 2°2558 84-00 2°2258 83°00 7 2°1946 82°00 21757 81:00 2°1479 80°00 2°1216 79-00 2°0922 2°d0 1:9675 The rate of increase of specific gravity is not uniform for equal increments of strength. It diminishes as the strength increases, as in the case of sulphuric acid, but not regularly. The diminution is very marked at the highest strengths. When sulphuric acid has arrived at the greatest strength attainable by ebullition—98°66 per cent.—its specific gravity is stated to decrease until the anhydrous acid, H,SO,, is reached. Selenic acid behaves dissimilarly in this respect; the increase of its specific gravity, although not uniform, is main- tained throughout. : Berzelius (‘ Traité de Chimie,’ 1830) mentions that selenic acid of 95°9 per cent. strength has a specific gravity of 2°6. Fabian gives 2°609 as the specific gravity of an acid of 94°9 per cent. strength, and 2°627 for an acid of 97'4 per cent. It will be seen that these results do not agree, nor are they consistent with those we have obtained. If values for the strengths mentioned be calculated from the foregoing oo 1889.] On Selenie Acid and other Selenium Compounds. 27 tables, an acid of 95°9 per cent. will be found to have a specific gravity of 2°5366, while the specific gravities of 94°9 per cent. and 974 per cent. acids will be respectively 2°5141 and 2°5680, being less than those assigned above. Furthermore, the difference between the two specific gravities given by Fabian is much less than we find between two acids differing by 2°5 per cent. The most probable explanation of the discrepancy is that the acids which gave the above results contained sufficieut selenium dioxide to raise their specific gravities appreciably. It may be shown that the effect of the development of selenium dioxide in selenic acid is to increase the specific gravity relatively to the acidity. In the acids above-men- tioned, selenium dioxide would exist as such, and not as selenious acid, owing to dissociation of the latter at a temperature below those at which the acids were formed, and the weak affinity for water possessed by the resulting dioxide. Clausnizer (‘ Liebig’s Annalen,’ vol. 196, 1879, p. 265) gives the specific gravity of selenium dioxide at 15°3° as 3°9538. We have also recently taken its specific gravity, and are in a position to confirm his result. It is thus more than one and a half times as dense as the strongest selenic acid. C. Blarez (‘ Comptes Rendus,’ vol. 103, 1886, pp. 804806) has examined the saturating power of selenious acid. He finds that it is monobasic with cochineal or methvl-orange. With litmus, 1t is monobasic to ammonia, lime, strontia, and baryta, but with soda or potash the litmus only becomes blue-violet when about 1°5 equivalent of alkali is added. We have obtained a hke result with soda or potash and litmus. When one equivalent of acid is saturated, there is a distinct change in the colour of the litmus, so that in the absence of other acids if might be used as an indicator for selenious acid. Taking 1°5 equivalent of alkali as the limit, the molecule of selenium dioxide in solution will have a less saturating power than that of selenic acid in the ratio of 2:15. This will be partly counterbalanced by the higher molecular weight of the latter, but the final effect of the sub- stitution of selenium dioxide for selenic acid will be to reduce the acidity. A gravimetric method, by which selenium dioxide would he oxidised and estimated as selenic acid, would also show a less acidity compared with the specific gravity than if the pure acid were used, but not to the same extent as when a volumetric process is employed for estimating the strength. The Action of Heat upon Selenic Acid. Action of Heat in a Vacuum.—The effect of heating dilute selenic acid ina vacuum up to 180° has already been described—dilute acid distils until that temperature is reached, when the anhydrous acid remains. - The result of further heating is merely for a time to raise the 28 Prof. Sir C. A. Cameron and Mr. J. Macallan. [May 2, temperature; the acid does not distil in the anhydrous condition. At about 200° it begins to decompose slowly, and at higher tempera- tures rapidly, into selenium dioxide, oxygen, and water. The latter serves to dilute a portion of the remaining acid, which then at once distils. In order to examine the effect of distilling the anhydrous acid destructively in a vacuum, a portion was heated in a flask con- nected with a condensing arrangement until rapid decomposition took place. The residue always consisted of a mixture of anhydrous selenic acid with selenium dioxide, the proportion of the latter increasing with the rise of temperature and length of time of heat- ing. The former was proved to be present by dropping in a crystal of anhydrous acid, when the liquid froze, and it also gave a coloration in the cold with the selenium test for the same acid which will be described hereafter. A portion which had been distilled for some time left a residue of which 0°7107 gram neutralised 18°50 e.c. of seminormal soda solution, using litmus as indicator, equivalent to 94°27 per cent. of acid calculated as selenic—a result which might be expected, owing to the influence of the selenium dioxide in diminish- ing the acidity, as has been already pointed out. The distillate consisted of selenium dioxide mixed with selenic acid. The latter was in a dilute state, since it would not solidify on addition of a crystal of anhydrous acid, nor would it respond to the selenium test: 04703 gram neutralised 11°11 ¢e.c. of seminormal soda solution, equivalent to 85°46 per cent. of acid calculated as selenic. Taking into account the diminution of acidity caused by the selenium dioxide, it is evident that a very concentrated, although not anhydrous, acid distils over. Action of Heat under ordinary Pressures — When dilute selenic acid is boiled at ordinary pressures nothing but water is evolved until 205° is reached, at which temperature it has the composition of the monohydrated acid. In these respects it behaves like dilute sulphuric acid. After passing 205° the distillate contains at first mere traces of selenic acid, but its strength gradually increases. ) >) 7 “ih x) 3) >>) 9 “3 bP) bP) 5 ft 3S gle ee approach. i. 240... approach. ” oy) 24°35 ” ” ” 24: a0) ” ” Oy i LOGS) Mike recession, 45 Or 3, recession. Remarks: Lines in nebula very faint and bisections very rough.” (‘ Greenwich Spectroscopic and Photographic Results,’ 1887).—May 13. | + Programme Royal Society Soirée, May 9, 1888, p. 12. f£ ‘ Greenwich Spectroscopic Results,’ 1884, p. 5. K f) A 1889.] On the Spectrum of the Great Nebula in Orion. 53 lines” (with two-prism train) “‘are very sharp. 5005 showed a faint fringe mainly on the side nearer the blue.” Mr. Maunder has. recently sent a note to the Royal Astronomical Society, in which he explains that the observation was made with a second half-prism added to the half-prism spectroscope. He says: “‘ The three principal lines of the nebular spectrum were seen as very narrow bright lines, but none of them were perfectly sharp, each showed a slight raggedness at both edges; but in the case of the line near X 5005 it was clear that this fringe, or raggedness, was more developed towards the blue than towards the red. In the case of the other two lines, they were not bright enough for it to be possible to ascertain whether the fringes were symmetrical or not. But » 5005 was clearly a single line. There was no trace of any bright line, or series of bright lines, close to it on either side; no trace of a fluting, properly so called. The entire line, fringes and all, was only a fraction of a tenth metre in total breadth.”* [It should be noticed that the instrumental conditione under which Mr. Maunder observed showed the second and third line “ not per- fectly sharp, but with a slight raggedness at both edges.”—May 13.] My own observations of this line, since my discovery of it in 1864, with different spectroscopes up to a dispersion equal to eight prisms of 60°, show the line to become narrow as the slit is made narrow, and to be sharply and perfectly defined at both edges. As some importance attaches to the precise character of this line, I wrote to Professor H.C. Vogel for permission to quote the result of his experience, which has been nearly as long as my own, of the character of this line. He says in his reply, dated 20th March, 1889: ‘‘ Beeile ich mich Ihnen mitzutheilen, dass meine langjahrigen Beobachtungen tiber die Spectra der Gas-Nebel vollkommen mit den Thrigen darin itibereinstimmen, dass die Nebellinie X) 5004 schmal, scharf und nicht verwaschen ist. Auch D’Arrest hat in seiner Unter- suchung tiber die Nebel-Spectra (Kopenhagen, 1872) nicht erwihnt dass die hellste Nebellinie unscharf sei.” Dr. Copeland permits me to quote the following sentences of a letter dated March 19, 1889 :—‘‘ Respecting the appearance of the line X 5004 in the spectrum of the Orion nebula, I may say that I have always drawn and seen it quite sharp and well defined on both edges. About nine years ago I made a special effort to divide it, if possible, with a large spectroscope in which the viewing telescope was 3 inches in aperture. The lines were then seen as sketched.” (The diagram shows the nebular lines with sharply ruled lines for edges.) ‘They were drawn by holding the note-book 10 inches from * ‘Monthly Notices R.A.S.,’ vol. 49, 1889, p. 308. 54 Dr. W. Huggins and Mrs. Huggins. [May 2, the left eye, in such a position that the image seen in the instrument with the right eye was apparently projected on the paper. If I had noticed any peculiarity about \ 5004, it would certainly have been noted.””* In an early observation of the dumb-bell nebula Professor Vogel, indeed, (‘ Beobachtungen zu Bothkamp,’ p. 59, 1872), describes this line as less defined towards the violet side. In a letter (April 3, 1889) Professor Vogel says this appearance of the line was probably due to a slit not sufficiently narrow. He says that he re-examined this line in his observations with the great Vienna refractor, and that it did not then appear otherwise than defined and narrow. The other line in the spectrum of the nebule upon which Mr. Lockyer mainly relies for the presence of magnesium is the line shown in my photographic spectrum of 1882,+ and to which I assigned - the wave-length of about 3730. Mr. Lockyer says of this line :{ “In the Bunsen as ordinarily employed the fluting at 500 far eclipses the other parts of the spectrum in brilliancy, and at this temperature, as already observed by Messrs. Liveing and Dewar, the ultra-violet line visible is that at 373.” Passing by a minor point, which Liveing and Dewar have already pointed out,§ namely, that their observation was made at the higher temperature of burning magnesium, this statement is insufficiently complete, for what occurs at this part of the spectrum, and is characteristic of the magnesium-flame spectrum, is a triplet, of which the line given by Liveing and Dewar at about 3730 is the least refrangible member. In the accompanying Diagram I give a representation of this triplet at the wave-lengths given by Liveing and Dewar, namely \ 3730, 3724 and 3720. In the photograph of 1888, in which the strong line can be seen distinct from the lines near it, the line is found to be very near the middle line of the triplet. I have therefore assigned to this line the position of about \ 3724. This line appears pretty strong, and there- fore if it were really one of the lines of the triplet, the other two members of the triplet should have appeared on the plate. On one side of the star-spectra this line is a little broader than on the other * Mr. Taylor, late of the South Kensington Laboratories, observing at Sir Henry Thompson’s observatory in November, 1888, says: “ The 5001 line is by far the brightest in the spectrum. It is never seen sharp, but with the narrowest slit always has a fluffy appearance, this being much more marked on the blue than on the red edge. This line was most carefully examined for evidence of structure, but was always found to be single, and no decided evidence of fluting structure could be made out. It may be that greater dispersion may show structure, but with the dispersion used here no structure could be seen.” ‘ Monthly Notices R.A.S.,’ vol. 49, p. 125. + ‘ Roy. Soc. Proc.,’ vol. 33, p. 425. {£ ‘ Roy. Soc. Proce.,’ vol. 43, 1887, p. 122. § * Roy. Soc. Proc.,’ vol. 44, 1888, p. 244. 1889.] On the Spectrum of the Great Nebula in Orion. 55 3710 vluuilanlu Nebula Lime side, but as a similar appearance is presented by G, and the stronger of the lines of the group, it may arise from some optical or photo- graphic cause. The line at 3724 impresses me strongly as asingle line, and there s certainly no trace of the first line of the triplet at 3730. The line appears to me stronger where it is upon the star-spectra. As therefore there seems to be little doubt that the ‘‘remnant of the fluting at 500” is not coincident with the brightest nebular line, and the next most characteristic group of this spectrum, the triplet at 3720, 3724, and 3730, according to Liveing and: Dewar, does not appear to be present in the photographs, we may conclude that the remarkable spectrum of the gaseous nebule has not been produced by burning magnesium.* IT should mention that Mr. Lockyer attributes one other line occa- sionally seen in the gaseous nebule to the flame spectrum of magnesium, namely, a very faint line at about \ 4700. Now, accord- ing to my experience, it is only in the spark and are that a line of magnesium appears at this place, a condition of the spectrum wher the lines at b are very conspicuous, and the band at A 5006°5 is usually absent. When, however, the spark is taken in magnesium chloride, the band is present under some conditions, but the triplet at b is always bright. I therefore consulted Professor Liveing, who * On the narrower basis of the magnesium spectrum only, Professors Liveing and Dewar point out that: “‘ the appearance of a line in the position of the first band without any trace of the second band, which is nearly as bright as the first, and without any trace of the 6 group, is quite sufficient to create a suspicion of mistaken identity when Mr. Lockyer ascribes the sharp green line in the spectrum of nebulz to this band of magnesia. This suspicion will be strengthened when it is noticed that the line in question is usually in nebule associated with the F line of hydrogen, if it be borne in mind that the spark of magnesium in hydrogen does not give the bands, and that the oxyhydrogen flame hardly produces them from magnesia when the hydrogen is in excess.” (‘ Roy. Soc. Proc.,’ vol. 44, p. 245.) Mr. Taylor records a brightening of the continuous spectrum of the nebula at A 5200, which he suggests may be magnesium. But this position is twenty-five units from that of the middle of the magnesium triplet at “0.” (‘ Monthly Notices R.AS.,’ vol. 49, p. 125.) 56 one OR: W. Huggins and Mrs. Huggins. © [May 2, says: “I have never seen the line at \ 4703 in the spectrum of the -magnesium flame. As it is a conspicuous line in the are and spark, we looked for it in the flame, but did not find it.” With reference to the second nebular line at \ 4957, Mr. Lockyer says:* ‘The lines at 500 and 495 have been seen in the glow of the Dhurmsala meteorite when heated, but the origin of 495 has not yet been determined.” And further (at p. 135): “I should add that the line at 495 makes its appearance much more rarely than the one at 500 in meteorite glows.” In the diagram on the same page this line is represented as coincident with the nebular line. The circumstance of a line appearing at 495 can scarcely be regarded, considering the very great number of spectral lines, as amounting to a presumption that the material to which it is due in the meteorite is the same as that present in the nebule which gives the line at 4957. If it should be shown that the unknown substance in the meteorite gives rise to a line at the position of the nebular line, namely, \ 4957, in that case the observation would have sufficient importance to make it desirable to compare the spectrum of the meteorite directly with that of the nebula. ‘Lanes Observed and Photographed in the Spectrum of the Nebula. Line measured by Dr. Copeland, probably D, A 5874:0 Brightesh limes sreleless esis c's Mine wees erat 50046 to 50048 WECONG MIME See nee as ale cw arcton ig RCA 49570 AiR FsVepae Fe, i MAN lleva ga 4860:7 Fourth dine. ley i Oe eo teia ess sesss, S anolontemercrer ees 4340°1 Line measured by Dr. Copeland .......... 44.76°0 Strong line in photographs 1882 and 1888 about 3724-0 Line in photographs 1888 about ........ » 3109:0 bP) 97 99 39 3699°0 ‘ anoub si... ofonw Photograph 1889. Ist pair.. { a ae 8741-0 : Te ee 3285:°0 d Zen: 1 Ronett(o% 3275-0 Line at.. Mesa e 3060°0 : ee 3053°'0 : ae gies { Meneame (07-0 (a 4116°0 La gees 4123-0 Photsoaraph 1688.5... Je. a: tis pres Lines across star spectra, 1st ape aN 4149:0 group eooeeeeveeeeeeeeeeese | Ba a dee 4154:0 Ch ae 4167-0 * “ Roy. Soc. Proc.,’ vol. 48, p. 183. i , # i ks { oo ; peak 4 , ; ze 1889.] On the Spectrum of the Great Nebula in Orion. 57 approximate 3998-0 ” 3988'0 PNG O OT OM basa aiaye) 120 shovels: e:ane) « 3975-0 mf 3959:0 , 3896-0 ¥ 3887°0 . 3878:0 aA 3870°0 EG OU OUD aia, a Aso me, © £6. .: AgCl. (1) Berzelius’s determination,........... 1 ee a ce UA Tie he cee ae pose stele 1s Sao (a) Washed with ether and alcohol.,..... 1 : 2206 bin wy Ge <) Ll. 2 2226 ]\. 2. 2268 (c) Exposed in vacuo over KHO.......... 1: 2'264 Without wash; 322... ee eres ele aL 2 reas 12 "2309 1 ae PrOOl (Gr = 90) ‘caleulated 25-05 eee Po. 23am The whole of the specimens analysed dissolved in water to a clear solution, with a slightly acid reaction. The determination which ~ 1889. ] Zirconium and its Atomic Weight. 83 shows the highest proportion of chlorine would give the atomic weight of zirconium as 92, which is undoubtedly too high, and, more- over, it will be quite evident from these numbers that no trustworthy determination was to be expected from this salt. The Tetrabromide. This salt was prepared by heating zirconia in an atmosphere of bromine vapour, but proved no more promising in its behaviour than the corresponding chlorine derivative. The Sulphate. Several methods of preparing the sulphate were tried, but ulti- mately that originally used by Berzelius was adopted. Finely powdered zirconia (air-dried) was heated with concentrated sulphuric acid, and most of the excess of acid driven off at as low a temperature as possible. In order to obtain the normal sulphate Berzelius drove off the excess of sulphuric acid, and then heated for a quarter of an hour, but never to redness; Mats Weibull heated till constant at 300°, a temperature manifestly too low. Cléve, ina private communication, advised me to heat in a sulphur bath (442°). It seemed, however, that in this instance, where the atomic weight depended on deter- minations from the sulphate alone, and especially since this is a general method applicable to several other elements, it was desirable that the limits of temperature within which the normal sulphate was stable ought to be ascertained. This was done in the case of a number of sulphates (Bi, Mg, Zn, Di), and the details of the investi- gation have already appeared (‘ Chem. Soc. Journ.,’ vol. 51, p. 676). The salt containing excess of sulphuric acid was heated in a bath, described in that communication, which could be easily kept within 5°, and at any temperature up to 500°. The boat containing the salt was weighed from time to time until it became nearly constant. The salt was then finely powdered, and the heating continued in periods of about four hours, until no further diminution of weight occurred, showing that the free sulphuric acid had been got rid of. The tem- perature of the bath was now raised by intervals of about 10°, and the heating continued for several hours at each limit, weighings being made after each increment until a point was arrived at at which loss of weight was again observed. This indicated that the temperature had been attained at which the normal salt began to undergo decom- position. We have then the limits of temperature within which the normal sulphate is stable. Several series of determinations were made, and one of these is given to show the character of the values obtained. — ei EE 84 » BEG. Mie Bailey. [May 9, Grams. Weighing tube. and: boat... ~~ ..2. 6.j-0 2.62 son eee 20°64962 ‘es af and sald 38 sseow no Ree 22-9095 After heating 6 hours at 300° ............ saan 22S aN OU sso Seno ee 22°9015 ee As, 300 Sek vee oo Ee eee 22-9002 : Bie as SS ey MAE Se 22°90012 Se Ae Se SON nore er Sacer Beha 22°90025 ‘ ASy s. SoU) sane bee hae ae aoe 22°90020 . AP gee ATO 3 tine tage ase eee 22°89820 The above numbers have not had applied to them the small correc- tions for variations of barometer and thermometer, and no importance need be attached to the differences of one or two tenths of a milli- gramme between 350° and 400°. It appears, therefore, from these experiments that zirconium sul- phate is stable up to 400°, and that the excess of sulphuric acid is driven off completely at 350°. If, therefore, a mixture of the salt and the free acid, prepared as above, be heated at any temperature between 350° and 400° till constant, we shall obtain the normal sulphate. The temperature of the sulphur bath would be too high, and of course at dull redness decomposition would set in. The Atomic Weight of Zirconium. After what has been said it may appear that the previous determi- nations of atomic weight from the sulphate would be too high rather than too low, since there can be little doubt that Berzelius heated the salt above 400°. It does not follow, however, that by heating it for a short time at a moderately high temperature more than a small fraction of the salt would be brought under conditions favourable to decomposition, nor even would the temperature of the mass be such that the whole of the free sulphuric acid would be got rid of. And the fact that on repeating such a treatment no variation in weight occurred, would be no guarantee that the salt was normal zirconium sulphate. My own experiments show that to get rid of the excess of acid requires prolonged heating, and at the same time renewal of the atmosphere in the vessel containing the sulphate. Apropos of this, Berzelius’s precaution to introduce into the crucible in the last stage of the ignition of the sulphate a little ammonium carbonate is a very necessary one, as it displaces often 2 or 3 milligrams of sulphuric acid, which otherwise seems to remain in the crucible time after time and fix itself in the zirconia, when the crucible begins to cool. Further- more, whatever previous experience may have been (for no special - precaution is mentioned in any case), I have found it most difficult to ignite zirconium sulphate without loss; the decomposition occurs 1889.] Zirconium and its Atomic Weight. 85 with such violence at first, and the resulting zirconia is so extremely light that, though every care was taken, varying results were got, even in igniting very gently over the bunsen burner, some as low as 43 per cent. of oxide instead of 43°3 at least. On carefully watching, it was seen that minute particles of zirconia were being carried out of the crucible, although the cover fitted well. This loss was only avoided by enclosing the crucible within a second larger one, whose cover fitted quite closely and only communicated with the external atmosphere by a drawn-out neck, so that there were no air-currents. Even then, if the crucible was placed over the blowpipe flame at once, loss occurred and it was necessary in every case to commence the’ operation over the flame of a bunsen burner, and then after half an hour to transfer to the blowpipe. Part of the determinations were made by Berzelius in the wet way —that is, the zirconia was first precipitated by means of ammonia, and then the sulphuric acid determined in the filtrate by precipitation with barium chloride. Having satisfied myself by careful comparative experiments that the results of both methods, under favourable conditions, correspond, I decided to adopt the dry method, viz., that of conversion of the sulphate into the oxide by ignition— (a.) Because it involved the least complicated operations and the fewest assumptions. (b.) Because under some circumstances basic zirconium sulphate is thrown down when ammonia is added to a solution of the sulphate. In the following paragraphs are given the determinations of Ber- zelius and Mats Weibull from the sulphate, followed by those based upon my own experiments. Berzelius’s Determination (‘ Pogg. Anun.,’ vol. 4, p. 126). From the analysis of the sulphate :-— SO; : ZrO, :: 100 : 75°84 | Ove : 75°80 > 75°74 shor Oe = (D100 Mieaa 25s. a. 75°853 ZrO, : 280;:: 15171 : 2 Bais ROE eS SHPO ek Me AES Ss BOIS Ek 86 Zirconium and its Atomic Weight. [May 9, Mats Weibull’s Determinations. ZrO, Zr(SO4)>. ZrO. Zr(SO4)a” 1°5499 grams. 06684 gram. 43 *126 per cent. 1°5445 __,, 0°6665 43 °153 4 2°1683_—y,, 0°9360 __—=z, 43 -168 55 1:0840 0:4670__,, 43°08h Soe 0-73i3" | 0°3422 so, 43 °321 es 0°6251_ soa, 0°2695 43 +113 9 | 0°4704 ,, 0°2027 43 091 "0 Total .. 8°2335 grams. ' 3°65523 grams. 43 °146 per cent. Mean determination :— Ge 2) QO) 225: O2:= Ad Zr > T:: 89:255 : 1 My own Determinations. ZrOz Zr(SOxz)2. ZrOz. Zr(SOs)a Portion A. 2-02357 grams. 0°87785 gram. 43 ‘381 per cent. 2°6185 ,, 1°1354 ~ ,, 43-3600 Portion B. 227709 grams. | 0 -°98713 gram. 43 *350 per cent. 221645, 0-96152 _,, 43°385 i, Portion C. 1°75358 grams. | 0°76107 gram. 43 4016 per cent. 1°64065_,, 0-7120 ,, 43397, Portion D. 2 °33255 grams. 1-°01143 grams. 43 361 per cent. 1°81105__,, 0-78485 _,, 43 3377 Totals... 16°67344 grams, 7 °23125 grams. 43°37 per cent. Maximum sgccins ete 5674: ] Zr.:H.2: GOes9 - 4 Minimum .....5.2 Ze 0:2 eos 1 Zt =Hize 90-237 - 1 Mean? \.5 sad .oe ) are 5664 : 1 Tee 90°401 : 1 1889.] Physical Properties of Iron at a High Temperature. 87 Corrections in the Weighings. - The balance used could be read directly to 4, milligram, and had been proved to be a most reliable instrument. The weights were an excellent set by Staudinger of Giessen, and showed an average varia- tion from the normal amounting to only 0:000035 gram. Corrections were introduced— (a.) For the weights. (b.) For displacement of air and variations in temperature and pressure. (c.) For variations arising by reason of the different hygroscopic conditions of the desiccator and balance case. In any case where condensation of moisture was liable to occur this was corrected for by noting the increment of weight per minute for several minutes whilst exposed in the balance case, and then con- structing a curve, with increment of weight and time as ordinate and abscissa, from which the necessary correction at the time of weighing could be introduced. In nearly all cases over 2 grams of the sulphate was used for each determination, and even with 2 grams a difference of 1 milligram in the weight of the zirconia obtained implies a dif- ference of 0°25 in the atomic weight; it is, therefore, evident that in some previous determinations, where less than a gram has been taken, there is considerable risk of error in the atomic weight. IV. “Magnetic and other Physical Properties of Iron at a High Temperature.” By JoHN Hopkinson, F.R.S. Received April 16, 1889. (Abstract.) This paper deals with the same subjects as are dealt with in three short papers* already read before the Royal Society. It gives full particulars of the experiments made both on the samples there men- tioned and on other samples. V. “ Determining the Strength of Liquids by means of the Voltaic Balance.” By G. Gorge, LL.D, F.R.S. Received April 17, 1889. * 1. “ Magnetisation of Iron at High Temperatures.” (Preliminary Notice.) ‘Roy. Soc. Proc.,’ vol. 45, p. 318. 2. “ Recalescence of Iron.” Tbid., p. 455. 3. “ Electrical Resistance of Iron at a High Temperature.” Ibid., p. 457. ) 88 Mr. W. N. Hartley. [May 9, VI. “On Films produced by Vaporised Metals and _ their Applications to Chemical Analysis.—Preliminary Notice.” By W. N. Hartury, F.R.S., Royal College of Science, Dublin. Received April 22, 1889. | Having recently communicated to the Royal Dublin Society (March 20th) a paper entitled ‘On the Constitution of the Electric Spark,” I have described a means of obtaining deposits of metals and of metallic oxides, which serves as a very delicate test for some of the metals. It has been considered desirable to devote much further study to the subject, and a method of working has been devised which, so far as it has been applied, appears to be especially useful in the examination of certain metallurgical products, as for instance in the detection and even estimation of the precious metals in copper, lead, and tin, and of certain impurities in copper. The method may be stated to be carried out in the following manner :—Hlectrodes of the metals to be tested are put into communication with the wires of an induction coil used for the production of condensed sparks, such as serve for the photographing of the ultra-violet spectra. When a plate of mica through which a series of pin-holes has been pricked is placed in the path of the spark and the current is passed for a period varying from 5 to 10, 15, 20, 30, and 60 seconds, a series of deposits of different degrees of tenuity are obtained, which are metallic with the noble metals, such as silver, gold, palladium, iridium, and platinum, and are oxides with such metals as are oxidisable, for instance magnesium, zinc, cadmium, lead, tin, copper, tron, nickel and cobalt, aluminium, indium, thalluum, arsenic, antimony, and bismuth. Gold gives films of extreme tenuity and beautiful in richness of colour, partly deep red or rose-tinted, but chiefly of a magnificent blue, with a shade of green in the thinnest part of the deposit. Silver gives yellow films, while palladium, iridium, and platinum give different shades of brown. The films are different as to the area which they cover, the difference being due to the volatility and the colouring power of the metals. Gold is by far the most remark- able in this respect. The colours of the oxides, such as various shades of brown with iron, cobalt, nickel, thallium, cadmium, bismuth, and yellow with zinc and lead, serve as tests by which they can be recog- nised. The vvlatility of the oxides is also a distinctive feature ; arsenic forms a remarkable series of rings round the pin-hole, and other metals, antumony standing next, are thus distinguishable. It is stated in the paper already quoted that beside the metallic deposit which silver gives, there is a yellow colour and a tinge of rose colour and violet. The silver employed was originally prepared by 1889.] On Films produced by Vaportsed Metals. 89 the late Dr. W. A. Miller, F.R.S., for spectroscopic purposes, and it is remarkably pure. The photographed spectra of this metal yield no lines traceable to gold or any other foreign element. (For its spectrum see ‘Phil. Trans.,’ 1884, pp. 109 and 134.) Nevertheless I considered that the rose-red and violet tints on the mica films were due to minute traces of gold. Since then, in order to prove or disprove this point, attempts have been made to prepare specimens of perfectly pure silver by the processes of M. Stas, but so far no samples have been obtained which can be relied upon as absolutely free from gold. In one case the chloride precipitated from a cold solution was digested several . times with hot aqua regia, washed completely free from soluble matter until the washings had no acid reaction, and subsequently _ reduced to metal by boiling with pure caustic alkali and milk sugar. This specimen was found to give a characteristic yellow film, but there was a trace of violet-grey surrounding the yellow of the silver, which resembled the colour obtained from metal to which traces of gold had been added, and which became deeper and deeper in colour as the quantity of gold was increased. An alloy was made by melting this sample of silver and adding thereto ,,4,th of its weight of pure gold.. The alloy was heated to boiling point for a minute; in order to agitate and completely mix the metals, the fused metal was kept in rapid rotation, and it was granulated by pouring it into water. The cooled metal was next treated in a manner intended to render it homogeneous in composition; thus, it was hammered out flat, broken in pieces, and again melted, the fused metal being granulated, and the solidified drops being again hammered into disks. By a precisely similar treatment alloys were made from this metal containing pro- portions of gold amounting to no more than 75355th and zop555th respectively. The hammered beads, generally about a decigramme in weight, were submitted to the action of the spark, and deposits of the metal on mica were obtained by passing the spark for 5, 10, 15, 20, 30, and 60 seconds. The difference between the deposits from the alloy containing seocth of gold was clearly seen with the naked eye in all cases. The alloy containing ,>53,,th was as clearly seen to contain less gold than the foregoing, and more than that with >5¢555th; and that with yousooth gave unmistakeable evidence of gold when examined with a 2-inch power under the microscope. The gold tints of rose-red and blue were observed as rings even in cases where the spark had passed for no longer than 5 seconds. Indeed these tests with the shorter duration of the spark gave the best evidence, since too much of the silver deposit obscured the characteristic colours. On the other hand, a much longer exposure of 10 or 20 minutes widely diffused the deposit of gold, and.rendered it evident outside the silver. It may 90 : 7 Presents. [May 9, © thus far be considered as proved that a decigramme of silver con- - taining y5g5a5th of gold gives a distinctive deposit of this metal, which is recognised by its colour, and that silver as pure as that obtained by the process of M. Stas which I have described gives no such decisive indication, though it does not yield films which can be considered as absolutely free from gold. Furthermore, this test for gold is more sensitive than that depending upon the employment of the spectroscope. Many specimens of copper and silver have been tested, and in each of them there appears to bea trace of gold. Gold of the fineness of 9, 12, 15, 18, and 22 carats has been shown to yield films each with distinctive characters. The various deposits of oxides and of some metals are easily treated with such acid and other reagents as are gaseous or capable of being volatilised, and the colour reactions of the sulphides may be obtained as definite rings of larger or smaller diameter, corresponding with the volatility of the metals. The application of this method may ultimately be made to lead to valuable results, but most of the large number of films already pre- pared have yet to be examined, and their properties described; it is therefore proposed to deal exhaustively with the subject in a future communication. Presents, May 9, 1889. Transactions. Alnwick :—Berwickshire Naturalists’ Club. Proceedings. Vol. XII. Part l. 8vo. [Alnwick 1888. ] The Club. Baltimore :—Johns Hopkins University. Circular. Vol. VIII. No. 72. 4to. Balttmore 1889; Studies in Historical and Political Science. Ser. 7. No. 4. 8vo. Baltimore 1889; Notes Supplementary to the Studies. Nos. 2-3. 8vo. Baltimore 1889. The University. Berlin:—K. Preuss. Akademie der Wissenschaften. Sitzungs- berichte. Jahrgang 1888. Nr. 38-52. 8vo. Berlin. The Academy. Catania:—Accademia Gioenia di Scienze Naturali. Bullettino Mensile 1889. Fasc. 4-5. 8vo. Catania 1889. The Academy. Emden :—Naturforschende Gesellschaft. Jahresbericht 72-73. 8vo. Hmden 1889. The Society. Kew :—Royal Gardens. Bulletin of Miscellaneous Information. No. 28. 8vo. London 1889. The Director. Leipsic :—Astronomische Gesellschaft. Vierteljahrsschrift. Jahr- gang XXIV. Heft 1. 8vo. Leipzig 1889. The Society. 1889.) Presents. 91 Transactions (continued). Konig]. Sachs. Gesellschaft der Wissenschaften. Abhandlungen. Bd. XV. Nr. 3-4. 8vo. Leipzig 1889. The Society. London :—British Association. Report. 1888. 8vo. London 1889. The Association. Entomological Society. Transactions. 188Y. Part 1. 8vo. London. The Society. London Mathematical Society. Proceedings. Vol. XX. Nos. 343-345. 8vo. [London] 1889. The Society. Physical Society. Proceedings. Vol. X. Part 1. 8vo. London 1889. The Society. Royal Meteorological Society. Quarterly Journal. Vol. XV. No. 69. 8vo. London 1889. The Society. Royal Microscopical Society. Journal. 1889. Part 2. 8vo. London. The Society. Royal Statistical Society. Journal. Vol. LIT. Part 1. 8vo. London 1889. General Index. 1873-1887. 8vo. London 1889. The Society. Milan :—Reale Istituto Lombardo di Scienze e Lettere. Rendiconti. Ser. 2. Vol. XX. 8vo. Milano 1887. The Institute. Societa Italiana di Scienze Naturali. Atti. Vol. XXX. Fase. 1-4. 8vo. Milano 1887-88. The Society. New York:—American Geographical Society. Bulletin. Vol. XXI. No. 1. 8vo. New York 1889. The Society. Vienna :—Kaiserliche Akademie der Wissenschaften. Anzeiger. Jahbrgang 1889. Nr. 4-8. 8vo. Wien. The Academy. K. K. Geologische Reichsanstalt. Verhandlungen. 1889. No. 3. Svo. Wien. The Institute. Cameron (Sir C. A.) History of the Royal College of Surgeons in Ireland. 8vo. Dublin 1886. The College. Johnston (R. M.) Systematic Account of the Geology of Tasmania. 4to. Tasmania 1888. The Government of Tasmania. Maiden (J. H.) The Useful Native Plants of Australia. 8vo. London 1889. The Author. Scacchi (A.) Catalogo dei Minerali e delle Rocce Vesuviane. Ato. Napoli 1889; Sulle Ossa Fossili trovate nel Tufo dei Vulcani Fluoriferi della Campania. 4to. Napoli 1888; La Regione Vulcanica Fluorifera della Campania. 4to. Napoli 1887. The Author. Sclater (P. L.), F.R.S.,and W. H. Hudson. Argentine Ornithology. Vol. IL. 8vo. London 1889. The Authors. Uslar (Baron P.) Ethnography of the Caucasus. Linguistics III. —The Avar Language [Russian]. 8vo. Tiflis 1889. | The Author, 92 Prof. E. Hull. Ona possible [May 16, May 16, 1889. Professor G. G. 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 :— I. “ On a possible Geological Origin of Terrestrial Magnetism.” By Epwarp Huu, M.A., LL.D., F.R.S., Director of the Geological Survey of Ireland. Received April 30, 1889. (Abstract. ) The author commenced by pointing out that the origin and cause of terrestrial magnetism were still subjects of controversy amongst physicists, and this paper was intended to show that the earth itself contains within its crust a source to which these phenomena may be traced, as hinted at by Gilbert, Biot, and others; though owing to the want of evidence regarding the physical structure of our globe nm the time of these observers, they were unable to identify the supposed earth’s internal magnet. The author then proceeded to show cause for believing that there exists beneath the crust an outer and inner envelope or “magma,” the former less dense and highly silicated, the latter basic and rich in magnetic iron-ore. This view was in accordance with those of Durocher, Prestwich, Fisher, and many other geologists. The com- position of this inner magma, and the condition in which the mag- netic iron-ore exists were then discussed, and it was shown that it probably exists under the form of numerous small crystals with a polar arrangement. Hach little crystal being itself a magnet, and having crystallised out from the magma while this latter was in a viscous condition, the crystalline grains would necessarily assume 2 polar arrangement which would be one of equilibrium. Basalt might be taken as the typical rock of this magma. The thickness and depth of the magnetic magma beneath the surface of the globe were then discussed, and while admitting that it was impossible to come to any close determination on these points owing to our ignorance of the relative effects of increasing temperature and pressure, it was assumed tentatively that the outer surface of the effective magnetic magma might be at an average depth of about 100 uniles, and the thickness about 25 or 30 miles. The proportion of mag- 1889.] Geological Origin of Terrestrial Magnetism. 93 netic iron-ore in basaltic rocks was then considered, and it was shown that an average of 10 to 15 per cent. would express these proportions ; and assuming similar proportions to exist in the earth’s magnetic magma, we should then have an effective terrestrial magnet of from 24 to 3 miles in thickness. The actual magnetic magma or shell might be very much thicker than that here assumed. Instances of polarity in basaltic masses at various localities were - adduced in order to illustrate the possibility of polarity in the internal mass. The subject of the polarity of the globe was then discussed, and it was pointed out how the position of the so-called ‘‘ magnetic poles” leads to the inference that they are in some way dependent upon the position of the terrestrial poles. The author regarded the so-called “double poles” as merely foci due to protuberances of the magnetic magma into the exterior non- magnetic magma, and considered that there was really only a single magnetic pole in each hemisphere, embracing the whole region round the terrestrial pole and thestronger and weaker magnetic foct, and roughly included within the latitude of 70° within the northern hemisphere. It was pointed out that the poles of a bar-magnet embrace a com- paratively large area of its surface, and hence a natural terrestrial magnet of the size here indicated may be inferred to embrace a pro- portionably large tract for its poles. In reference to the question why the magnetic poles are situated near those of the earth itself, this phenomenon seemed to be con- nected with the original consolidation of the crust of the globe, and the formation of its internal magmas. It was pointed out that, owing to the differences of temperature which must have existed in the polar regions, as compared with those of the equatorial, the process of solidification has been more rapid in the polar regions than elsewhere, and it was inferred that in the case of the magnetic magma the process of crysta!lisation and the polar arrangement of the particles of magnetic iron-ore would proceed from the poles towards the equator in a radial direction. The manner in which the phenomena of magnetic intensity, and of the dip of the needle at different latitudes could be explained on the hypothesis of an earth’s internal magnet, such as here described, was then pointed out, and the analogy of such a magnet with a magnetic bar passing through the centre of the earth was illustrated. The author then proceeded to account on geo-dynamical principles for the secular variation of the magnetic needle, and also to show how the objections that might be raised to the views here advanced, on the grounds of the high temperature which must be assumed to exist at the depth beneath the surface of the magnetic magma, could be met by considerations of pressure, and on this subject read a letter which he had received from Sir William Thomson, F.R.S. ? 94 Drs. 8S. Martin and R. N. Wolfenden. [May 16, In conclusion, the author stated it was impossible in a short abstract to go into the details of the subjects here discussed, and for further information the reader must be referred to the paper itself. II. “ Physiological Action of the Active Principle of the Seeds of Abrus precatorius (Jequirity).” By SipneEy Martin, M.D. London, British Medical Association Research Scholar, Assistant Physician to the Victoria Park Chest Hospital, and R. NorRIS WOLFENDEN, M.D. (Cantab.). (From the Physiological Laboratory, University College.) Communi- cated by E. A. ScHAFER, F.R.S. Received April 11, 1889. The object of the present investigation was to study the physio- logical action of the active principle of the jequirity seed. ... 2... an Oras is Drake oe PRM IOSUCLIONs-. oo.2 > ss uon.. Aga Pe Turning now to specimen b, we find that it presents a most inte- resting state of affairs, although had the animal lived but a day or two longer, all its interest for our present purpose would have vanished, for it has all but completed the process of shedding its teeth. On opening the mouth there was seen the usual set of hollows, surrounded by hardened epithelium (fig. 3), characteristic of the first stage in the development of the cornules. Two large hollows were to be seen on each side of each jaw, and a minute additional one in front above, and behind below, these hollows being of course afterwards the concavities on the surface of the cornules. The hollows were all filled up nearly level with the surface with bits of earth and sand, and fragments of food. On cleaning this out bit by bit, twoy of the eight large hollows were found to contain something in addition, and a close examination proved that this something was in each case a worn-down tooth, reduced to about the thickness of paper, and with all the outlines worn off. These remnants of teeth were quite unattached, coming away freely, and would evidently very soon have fallen out of their own accord. No epithelium was over them, but all that surrounding and beneath them was commencing to indurate and thicken, in order to form what would later have been the cornule. These two specimens, therefore, prove the contentions put forward above; a shows that the teeth are functional, completely calcified, and placed as usual close to the bone; b that, after being worn down by genuine use, they are shed from the hollows in the surface of the cornules, which grow up beneath and around instead of being formed above them. The specimens examined by Mr. Poulton were all from animals far younger than in the case of those now described; so far younger, in fact, that instead of being at, or nearly at, their furthest organs in such a state of decadence as are the teeth of Ornithorhynchus, a view that is borne out by the marked differences between the teeth now described and those of the College of Surgeons specimen.—May 20, 1889. * This suggestion is confirmed by Professor Stewart’s specimen, in which the teeth have well-defined roots—May 17, 1889. + The anterior right and the posterior left of the upper jaw. VOL. XLVI, K Chats es ie 130 Mr. O. ‘Thomas. [May 16, point of development, as was then not unnaturally supposed, they were merely commencing to undergo calcification within the tooth- capsule, just as would have been the case with those of any other young mammal. But in some ways the point that is of most importance in the discovery of fully-developed Monotrematous teeth is the fact that for the purpose of comparison with those of other mammals, a comparison to which of late great attention has been directed, we have now available perfect calcified teeth, of a size sufficient for inspection with the naked eye, and very far superior to anything that figures compiled from microscopic sections can possibly be. Such a comparison I would have willingly now made, but unfor- tunately the most careful search* among cther animals, fossil and recent, mammalian and reptilian, fails to reveal any teeth quite corresponding to those of Ornithorhynchus. But, nevertheless, their study inclines one more and more to believe in the correctness of Professor Cope’st ingenious suggestion as to the Monotrematous, or, as I should prefer to say, Prototherian, nature of the Mesozoic Multituberculata. These animals, long looked upon as Diprotodont Marsupials, have of late been much studied in America,§ where large numbers of them have been found. Many of them (e.g., Bolodon, Allodon, Ptrlodus, and, especially, the best known of all, Microlestes and Plagiaulax) have molar teeth which are broad and low-crowned, and which have a series of cusps running around their edges, so that each tooth has two rows of cusps corresponding in a general way to the cusps on one side and the crenulations on the other in the teeth of Ornithorhynchus. A figure of one of the molar teeth of Microlestes is given (fig. 5) to show how far it resembles those of the living form. Still it must be insisted that the resemblance between the Multituberculate- and the Ornithorhynchus-teeth is of the most general character, and that the two are certainly widely separated genetically, even if we do admit that they appear to possess a relation- * In this search I have had the advantage of the assistance of Mr. R. Lydekker and Mr. G. A. Boulenger. + ‘Amer. Nat.,’ vol. 22, 1888, p. 259. Professor Seeley’s remarks in 1879 (‘ Quart. Journ. Geol. Soc.,’ vol. 35, p. 456 et seg.) on the relationship to the Monotremata presented by a Mesozoic humerus and femur assigned either to Phascolotherium or Amphitherium do not touch the question, since neither of these animals are Multituberculata, both belonging to the Polyprotodont division of the Mesozoic mammalia.~—May 17, 1889. t The Eocene Neoplagiaulax, Lemoine (Paris, ‘ Soc. Géol. Bull.,’ vol. 77, n. 249), also belongs to this group, and has teeth that present a certain resemblance to those of Ornithorhynchus. Compare Plate V, fig. 3, and VI, figs. 17-19, of that work with the figures now given. § See papers by Cope, Marsh, Osborn, Scott, and others. Proc hoy Soc. Vol46. P12. a ee 1889.] On the Dentition of Ornithorhynchus. 131 ship nearer to each other than to any other known groups of mammals. In any case, since the form and structure of the teeth are of neces- sity the chief means of determining the evolutionary history of the Mammalia, the discovery now made, in giving us gennine modern Monotrematous teeth to work from, provides one of the most im- portant aids to the elucidation of the systematic position of these anomalous mammals that has yet been obtained. Finally, it may be noted that the absolute continuity of the epithe- lium with the developing cornule, combined with the presence of such well-developed calcified teeth, proves again, if after Mr. Poulton’s paper further proof is needed, that the view* as to the cornules being degenerated true teeth is wholly untenable. EXPLANATION OF PLATE 2. Fig. 1. Left upper teeth of Ornithorhynchus (x 5). Drawn from specimen a (see supra) ; the rim of indurated epithelium still present. 2. Left lower teeth (x 5). 3. Left side of palate of specimen 6, showing (a) the empty anterior alveolar hollow, (4) the worn-down posterior tooth not yet shed, and (c) the elevated rims of epithelium that would later have formed the walls of the ccrnules. 4, The same in the lower jaw, but here all the teeth have been shed: ¢ as in 3. . Molar tooth of Wicrolestes, much magnified. 6. Series of diagrammatic sections showing development of tooth and cornule.+ a. Tooth (¢) still in capsule below gum; e, epithelium. This sketch is taken from one of Mr. Poulton’s figures of the early stages of the teeth. b. Tooth just before eruption. e. Eruption of tooth and ccnsequent cutting of the epithelium, which com- mences to thicken at c for the formation of the cornule. d. Creeping of epithelium underneath tooth, until it presses against and gradually causes absorption of their roots. e. Tooth just before it is shed. Its roots have been absorbed, and the epithelium has passed right beneath it. The cornule is now definitely separated (at x) from the ordinary epithelium, and its edges are so developed as to overtop the cusps of the tooth. Jf. Fully developed cornule. On * Seeley, ‘ Roy. Soc. Proc.,’ vol. 44, 1888, p. 129. + These diagrams were drawn up in consultation with Mr. Poulton, so that he is equally responsible for them with myself. LoZ Presents. Presents, May 16, 1889. Transactions. Boston :—Society of Natural History. Proceedings. Vol. XXIII. Parts 3-4. 8vo. Boston 1858. The Society. Kdinburgh :—Royal Society. Proceedings. Vol. XV. No. 128. Vol. XVI. (Pp. 65-128.) 8vo. Hdinburgh 1889. The Society. London :—Quekett Microscopical Club. Journal. Vol. Ill. No. 24. 8vo. London 1889. The Club. Society of Biblical Archeology. Proceedings. Vol. XI. Part 6. 8vo. London 1889. The Society. Zoological Society. Transactions. Vol. XII. Part 8. Ato. London 1889; Proceedings. 1888. Part 4. 8vo. London 1889. | The Society. Lund :—Universitet. Ars-Skrift. Tom. XXIV. 4to. Lund 1887-88. The University. Milan :—Reale Istituto Lombardo di Seienze e Lettere. Memorie (Classe di Lettere e Scienze Morali e Politiche). Vol. XVIII. Fasc. 1. Memorie (Classe di Scienze Matematiche e Naturali). Vol. XVI. Fasc. 2. 4to. Milano 1887-88. | The Institute. Newcastle-upon-Tyne:—North of England Institute of Mining and Mechanical Engineers. Transactions. Vol. XXXVIII. Parts 1-2. 8vo. Newcastle 1889. The Institute. Paris :—Ecole Normale Supérieure. Annales. Année 1889. No. 4. Ato. Paris. The School. Société Philomathique. Bulletin. Tome I. No. 1. 8vo. Paris 1889. | The Society. Rome :—Accademia Pontificia de’ Nuovi Lincei. Atti. Anno XXXIX. Sessione 2-4. 4to. Roma 1886. The Academy. R. Comitato Geologico d’ Italia. Bollettino. 1889. Nos.1le 2. 8vo. Roma. The Comitato. St. Petersburg :—Académie Impériale des Sciences. Mémoires. Tome XXXVI. Nos. 12-13. 4to. St. Pétersbourg 1888-89. ; The Academy. Journals. American Journal of Philology. Vol. 1X. No. 4. 8vo. Baltimore 1888. | The Editor. Annales des Mines. Sér. 8. Tome XIV. Livr. 6. 8vo. Paris 1888. L’Hcole des Mines, Paris. Glasgow Medical Journal. General Index. 1828-88. 8vo. Glasgow 1889. Glasgow and West of Scotland Medical Association. Horological Journal. May—December, 1888. January—May, 1889. 8vo. London. British Horological Institute. Limit of Light im the Ultra-violet part of the Spectrum. 148 Journals (continued). _ Medico-Legal Journal. Vol. VI. No. 3. 8vo. New York 1888. The Editor. Naturalist (The). Nos. 165-166. 8vo. London 1889. The Editors. Revista do Observatorio. 1889. Num. 2-3. 8vo. Rio de Janeiro. Imperial Observatory, Rio de Janeiro. Revue Médico-Pharmaceutique. 1889. No. 2. 4to. Constantinople. The Editor. Stazioni Sperimentali Agrarie Italiane (Le). Vol. XV. Fasc. 3. Vol. XVI. Fasc. 1-3. 8vo. Roma 1888-89. The Editor. Technology Quarterly. Vol. II. No. 3. 8vo. Boston 1889. . The Editors. Zeitschrift fur Naturwissenschaften. 1887. Hefte 3-6. 1888. Hefte 1-4. 8vo. Halle. Naturwissenschaftlicher Verein, Halle. “On the Limit of Solar and Stellar Light in the Ultra-violet Part of the Spectrum.” By Wituiam Hueerns, D.C.L., LL.D., F.R.S. Received March 28,—Read April 4, 1889. It has been long known that the solar spectrum stops abruptly, but not quite suddenly, at the ultra-violet end, and much sooner than the spectra of many terrestrial sources of light. The observations of Cornu, of Hartley, and, quite recently, of Liveing and Dewar, appear to show that the definite absorption to which the very rapid extinction of the solar spectrum is due, has its seat in the earth’s atmosphere, and not in that of the sun; and that, consequently, all ex-terrestrial light should be cut off at the same place in the spectrum. During several years I have attempted to obtain the limit in the ultra-violet for stellar light here, but as it was necessary to make use of a bright star at a high altitude, and at a time when the atmosphere was very clear, it was not until September 20th, 1888, that I was able to obtain a result which seemed to me to be satisfactory. On that night three successive photographs of Vega, with increas- ing exposures, were taken on the same plate. The first spectrum was exposed for 10 minutes, the second for 20 minutes, and the third spectrum nearly four times as long, namely, for 70 minutes. A comparison of the extent of the second spectrum due to an exposure of 20 minutes with that of the third spectrum, to which an exposure of 70 minutes was given, leaves no doubt that the latter spectrum has reached the limit imposed by atmospheric absorption, and has not stopped in consequence of an insufficient exposure of the plate. stil 134 Dr. W. Huggins. On the Limit of Solar and Stellar The original plate has been enlarged about four times; and a spectrum of magnesium and calcium, taken with the same Aeyyaneie and enlarged simultaneously with the plate of stellar spectra, has been placed above to serve as a scale. As the spectra are prismatic it is not possible to indicate the wave- lengths in a scale of equal parts. A short scale only is placed over the spectrum where the light of Vega ends. The spectroscope with which the spectra were taken is furnished with a prism of Iceland spar and lenses of rock crystal, and a mirror of speculum metal was used to condense the light of Vega upon the slit. It will be seen that at my observatory* the light of Vega at about \. 8000 is abruptly weakened, and then continues as a very faint line so the point of apparent extinction at » 2970. Numerous solar spectra taken here during the last four years with the same spectroscope show an average abrupt weakening at about \ 3000, and an apparent total extinction at about \ 2985. On two occasions only the very faint weakened spectrum could be traced as far as \ 2970. The abrupt narrowing of the spectrum at the end towards the red is produced by the rapid falling off of sensitiveness of the silver bromide for light of increasing wave-length. The increase of breadth of the spectra with increase of duration of exposure is due to the same causes, optical and photographic, which produce the increase of diameter of stellar disks on the photographic plate with longer exposures, when a reflector is used. At h the breadths of the spectra, having 20 minutes and 70 minutes exposure respectively, are 0°06 inch and 0°105 inch.T In 1879 Cornut made experiments on the limit of the solar spec- trum with reference to the altitude of the place of observation. On the Riffelberg, at an elevation of 8414 feet, the spectrum reached to d 2932, while at the lower elevation of Viege, 2163 feet, the spectrum stopped at 2954. He concludes that the absorption is due to the gaseous constituents, and not to aqueous vapour in the atmosphere. In 1881§ Hartley stated that an amount of ozone proportional to * Elevation of the observatory 177 feet above mean sea level. Barometer about 30°03 inches at the time of observation. + The law of increase of size of image with exposure is not as yet accurately defined. Bond found that the diameter of star-disks varied nearly as the square root of the time of exposure. Pritchard, using a reflector, found a law near the fourth root ; and Mr. H. H. Turner has recently found a law very near the cube root for plates taken with a photoheliograph object-glass (‘ Astron. Soc. Month. Not.,’ vol. 49, p- 292). t “Sur Absorption Atmosphérique des Radiations Ultra-violettes,”’ ‘Journ. de Physique,’ vol. 10, 1881. § “On the Absorption Spectrum of Ozone, and on the Absorption of Solar Rays by Atmospheric Ozene,” ‘Chem. Soc. Journ.,’ vol. 39, 1881, pp. 57, 111—129. Light in the Ultra-violet part of the Spectrum. 135 the average quantity in a vertical column of the atmosphere, caused an absorption similar to that observed in the solar spectrum, namely, : terminating about » 2950. ' Quite recently Liveing and Dewar have made some important, experiments on the absorption-spectrum of large masses of oxygen under pressure.* They state that with a tube 165 em. long and a pressure of 85 atmos., oxygen appeared to be quite transparent for violet and ultra-violet rays up to about \ 2745. From that point the light gradually diminished, and beyond X 2664 appeared to be wholly absorbed. In some later experiments with a steel tube 18 metres long and a pressure of 90 atmos., oxygen produced complete absorption above P, | 1.0. % 3309 °2. | M. Janssen, from his observations on the Alps, concludes that both the bands which follow the law of the square of the density, and the dark lines obeying a different law of formation, which are due to oxygen in the solar spectrum, are produced exclusively by the earth’s atmosphere—“ L’atmosphere scolaire n’intervient pas dans le phéno- meéne.”’+ * “Chemical News,’ vol. 58, p. 163, and ‘ Phil. Mag.,’ September, 1888, pp. 286— 290. + ‘Comptes Rendus,’ vol. 107, p. 677. ee | * [oa ° i cp 9 Re 136 Dr. J. Monckman. The Specific “The Specific Resistance and other Properties of Sulphur.” By James Moncxman, D.Sc. Communicated by Professor J. J. THomson, F.R.S. Received November 10,—Read December 6, 1888. Resistance. It is well known that sulphur in a solid state insulates electricity of very high potential, and conducts heat badly; also that it undergoes a curious series of changes when heated—melting at about 120° C.., becoming thicker at 200° to 250°, more liquid at 250° to 300°, and boiling under atmospheric pressure at 440°. During the past three terms I have been engaged in the Cavendish Laboratory in trying to determine whether these changes are accompanied by corresponding ones in the electrical resistance and other properties of the element. I expected that the changes would be within the limits of an insu- lating body, hence my first experiment was designed to test the insulating power for frictional electricity. Two platinum wires were placed in a beaker of melted sulphur at a distance of about 1 cm. apart, one being connected to an electro- scope, the other going to earth. When the sulphur became solid the leaves of the electroscope remained open on charging for a con- siderable time, but fell at once if any portion of the sulphur between the wires was liquid. To avoid all discharging by the flame used in melting the sulphur, the platinum wires were fixed to an ebonite rod at the proper distance apart. After melting the sulphur the flame was removed to a distance and the wires placed in the liquid. The discharge was complete and, apparently, as sudden as when con- tact was made with a wire. The same experiment was tried with paraffin, and the discharge found to be very slow. Seeing then that the resistance was removed by melting the sulphur into the region of conductors, it became necessary to find some method that could be used for conductors of very high resistance. At Mr. Glazebrook’s suggestion I tried placing the wires in melted sulphur in circuit with a high resistance reflecting galvanometer and a set of accumulators giving a total electromotive force of 60 volts. With platinum wires in the sulphur no reliable results could be obtained as the current quickly fell away. While thus engaged my attention was directed to a paper by M. Duter (‘Comptes Rendus,’ vol. 106, 1888, p. 836), in which he describes some experiments on boiling sulphur. Platinum he found to be attacked by the sulphur, but gold gave good results; no measurements were, however, given. Following Duter’s plan I ‘used Resistance and other Properties of Sulphur. 137 gold electrodes, but failed to get a steady current to pass; neither did ordinary carbon plates answer any better. ’ Having some graphite rods which had been procured from Hogarth and Hayes, Keswick, for some experiments on carbon, I tried two of them, and obtained a perfectly constant flow of electricity even at the boiling point. The change in the resistance between melting point and boiling point was so great that it was difficult to arrange a method that would give reliable readings. In the Cavendish Labora- tory, where this work was done, we have a set of 26 accumulator cells which when charged give a potential of about 60 volts. This is conducted to all the rooms, and is so arranged that we can use any number of cells, so that we can vary the potential from 60 volts to about 23 volts. When the sulphur was melted (125° C.) 60 volts gave a deflection with a reflecting galvanometer of 11,770 ohms resistance of only half a millimetre on the scale, while at 440° C. one cell gave a deflection of 60 mm. _ By changing the number of cells, and measuring the potential by a Thomson’s graded voltmeter at each change, the results given in the following tables were obtained. The graphite rods were carefully insulated from each other by hard glass tubes, over which shorter pieces of tube of unequal length were placed, and fixed with plaster of Paris, the object being to give as much insulating surface as possible. A cell of mica was placed around the projecting part of the graphite rods to render the path of the current fairly parallel; the ends were left open to allow free access of sulphur and to prevent vapour taking the place of the liquid when ebullition commenced. The form of the mica cell was preserved by an outer cell of thin glass. In the figure, A, A are the graphite rods, B, B glass tubes, C, C 138 Dy. J. Monckman. The Specific larger ones, D mica. The exposed ends were filed flat, and fit loosely into the tube D. The dimensions are: length, 30 mm.; width, 32 mm.; distance, 7 mm. between the free ends, a, b. The change of resistance was so great and fell so quickly at the higher temperatures that it gave rise to a suspicion that the increase of conductivity might arise from particles of the rods being torn off and mixed with the sulphur. To test this, the rods were placed in a second tube of boiling sulphur, so that when placed in the tube of pure sulphur they might not reduce the temperature of the liquid. After removing and allowing the adhering liquid to flow back, they were placed in the other vessel, and the current passed at once. ‘The deflection was the same as before, and steady, neither did the rods appear to be acted upon in any way. Hence we concluded that the change was in the sulphur itself. Resistance.—Ordinary roll brimstone :—- Reduced to one standard Temperature. Potential. Deflection. by multiplying by 60/v. Gail, a ul hc. Bh BU) earth. 1560 POO tie Bees PMS es eh Wee b's jo esa al 325 Bi eens Pe es Abe oa kee NN: 52 OD ne fe sw teas 555i eerRials, ovate dpe eee 5 26 ZOO. ee chee exe 5 ae Oy LOe ee Srecheeene 24, DLO cciievaiannct Sele tm: joie) kee eee O*.,| ene tees 7 1D alba Basypiees ese 07 amr ie 8 1 he, alas ene 6 Potro. ee. sila econ: 5 ah eee 5 140) Sete sot salt eines ouees 2a \ Wie lahat peas 2 mera a i) oS) VRE: DR a daa 0°5 Another specimen gave slightly different numbers, but of the same order. With precipitated sulphur the resistance was _ considerably higher. AAW A ee Ai] ices sre DORE we ae ne ae 512 OW) Mim: one re eee DO sat ieee 73 330) Soe ee amare: 3 44 BO hive clcktaeeees 8° 2 Beet teteuiens TAR che wie Cc 51 73) AS e Ai: : Bogota fe stern pene si, We 5°5 OOM. sain ahs ee ig See og 2°8 7, ena 59 | Memenreemewters () 25) os 0°50 sae Se aD a could get upa...... swing only. The specific resistance may be calculated from these tables, using the quantities previously given, namely, 1. 30 mm., w. 33, d. 7; and Resistance and other Properties of Sulphur. 139 the value of each scale division is 0:038 milliampére of current passing per second. Hence since E/R =c we get— a = 000000116 ampare R = 3,553,448 ohms. Specific resistance = R xX ae = Lo” x ky = 9,600,000 neatly, or 5 X 10° ohms at 440°; at 260° it is nearly 1000 times that number, or 5 x 108. Roll sulphur gives the same resistance at 125°, that is, 5 x 108; while at 440° it is one-third precipitated sulphur, or 1:6 x 105. The accompanying curve shows the conductivity of precipitated sulphur. At 290° C. there appears a sharp bend in the line. Up to that point the conductivity rises to 5°5, becoming 51 in the next 45°, after which it rises rapidly. This bend coincides fairly with the second fluid state, and probably indicates some molecular change which appears to produce similar irregularities in its other properties. Deflecttort SHE: I Conductivity, é 500 aie oi Inbal ot eabcdadede TT TTP “Goda ie Balpe | Boiling Povnt. The first of these tested was the effect of pressure upon the boiling point. The apparatus used is given in the next diagram, the sulphur being placed in the space B, whilst the larger spaces, C and also D, were surrounded with sheet asbestos to prevent rapid radiation. The tube A was connected with an air-pump and mercury gauge. When the sulphur in B was heated, on exhausting the air the first time there was a violent temporary evolution of gas at 240°C. if the pressure was 23 cm.; butif the air was withdrawn until the gauge registered 1 mm., this ebullition took place at 150° C. This escape of 140 Dr. J. Monckman. The Specific gas took place even after the sulphur had been boiled at the ordinary pressure of the atmosphere, and also after a considerable evolution at 150° when, apparently, all gas was driven away, a second one occurred on raising the temperature. One or two precautions are necessary in order to get good results. The sulphur is a bad conductor of heat, and therefore one part of it near the flame may be many degrees above another in the interior. The vapour from tke hotter bursts through the cooler liquid and rising into the space C causes a higher temperature to be registered than the true one. By reducing the flame, and by surrounding the portion B with a conductor such as mercury for temperatures below 350°, the heat can be regulated and spread until this is avoided. The curve is drawn from data furnished by experiments at various temperatures up to 340° only, one temperature being taken above that, d GESSUIEC.T i ‘bees Me LAG n OUT: ae "240 oP 60 70 80 390 30 Lemp Resistance and other Properties of Sulphur. 141 namely, 440°. There appears the same change at 290° as in the previous curve which it closely resembles. At one time I thought that sulphur might be added to the list of bodies given by Ramsay and Young in their paper on “ Evaporation and Dissociation” (‘ Phil. Trans.,’ 1884, p. 461) as a means of obtain- ing arange of temperature above 350° up to 440°. The chief difficulty arises from the overheating, before mentioned, and the danger of breaking a vessel of solid sulphur on reheating. The first can be avoided by carefully heating, and the second is very much reduced when the sulphur is allowed to solidify under much diminished pressure. The two curves given above are so nearly identical that one naturally suspects that the former is produced by the increased mobility indicated by the latter, and that if the measurements for resistance were taken at each temperature when the liquid was under pressure so diminished that ebullition took place, the mechanical agitation of the particles would produce a decrease of the resistance in addition to that due to the temperature alone, and carry off the charge somewhat after the manner of air and a pointed conductor in electricity of high potential. That this was not so was proved by placing the graphite rods in the vessel used for the last experiments. After heating and exhausting to expel the gas measurements were taken at various temperatures ; in one set the sulphur boiled under diminished pressure, and in the other set the air was admitted. No difference could be detected. Hapansion. Having failed to obtain measurements with the specific gravity 142 Dr. J. Monckman. The Specific bottle from the difficulty of preserving the bottle on remelting the sulphur, a tube was used shown in the figure at A. The capacity of the bulb was 13°6 cm. The second vessel contained sufficient mercury to cover the bulb of A, and the stem to the point to which the sulphur rose on heating. : The bulb was filled with sulphur, and the whole of it kept beneath the surface of the mercury except when a reading was taken. From several series of experiments the curve was prepared. ,!20,30 40 50 60 70 60 90 200.10 20 30 40 50.60.70 80 Lenp Pei Chemical Affinity. If the changes previously noticed are produced by some change in the molecules of the element, it will probably show itself in the action of sulphur when strips of metal are exposed to its attack. We know that some metals are acted upon at ordinary temperatures in a slight degree, and with increased energy as the temperature rises. Others do not appear to be changed until a high point. It therefore appeared probable that by carefully watching strips of different metals exposed to sulphur at various temperatures, it might be discovered whether there was any point of sudden increase, and if so what relation it bore to the curves already obtained. A test tube was used for the sulphur, and a strip or piece of the metal having been placed in it, the tube was immersed in heated mercury. Temperature. 120° C..... After expelling all the air by a stream of coal-gas, sodium was dropped in. Took fire. TSOP jos, -3) Heated four hours with occasional shaking. Hg, Cu, and Pb slowly attacked. Me, Zn, and Sn not. 245 to 270° He formed a dark malleable mass, filled with globules of the metal. Cu more readily acted on. Resistance and other Properties of Sulphur. 143 Temperature. 290 to 310° Cu almost eaten away. Pb as before. Mg, Zn, and Sn not attacked. Again pieces of copper, of equal sizes and weights, were cut from the same sheet. After having been carefully cleaned and weighed they were exposed to sulphur at different temperatures for 15 minutes, after which they were carefully cleaned and re-weighed. Weight of Te: Loss of Rise of emperature. oi tare 1 copper used. weight. temperature. (1) 11°34 grams.. 24.0° 0°89 12° (2) we a 280 0°92 af (3) 3 He 300 1°62 30 The last column gives the increase of temperature due to the union of the copper and the sulphur. It occurred two minutes after the cold copper was introduced. At first there was a fall of 4° in the two first experiments, and 5° in the last; this was followed by a rise. The lamp was withdrawn when the temperature rose to that at which the experiment commenced. At the end of two minutes the rise given in the fourth line was observed. It appears, therefore, that there is a gradually increasing action up to 290°, or about that temperature, and above that a considerable increase. The point of change in resistance, 290°, appears to be one of considerable importance, carrying also the duidity, boiling point, and chemical affinity, &e. - Action of Light on Sulphur. That the metals of the same group in the arrangement according to the Periodic Law have properties in common is well known. Thus chlorine, bromine, and iodine belong to the same group, and are in many respects very similar bodies. Sulphur belongs not only to the same group as selenium, but is the next element in front of it. Natur- ally, therefore, we expect that they will have properties in common, and possibly the action of light in the case of selenium may be shared in an inferior degree by sulphur. This appears more pro- bable from the well-known fact that a saturated solution of sulphur in bisulphide of carbon is rendered turbid by direct sunlight, part of the sulphur being changed and becoming insoluble in that liquid. A portion of the sulphur undergoes the same change when exposed to a high temperature. In order that the sulphur used in the experi- ment might be as sensitive as possible to light, it appeared desirable as 144 Dr. J. Monckman. The Specific that only pure soluble sulphur should be used, and that great care should be taken not to raise the temperature in melting it so high as to produce any of the insoluble modification. Two rectangular graphite rods were placed parallel to each other, the one projecting about an inch at one end, the other at the other end. The edges were turned towards each other, as shown in the figure, leaving a space of one millimetre, which was filled with melted sulphur. This was levelled off with a hot iron to make the portion between the corners as thin as possible. When one of the projecting ends was placed in contact with a charged electroscope, the other being to earth, the charge fell more quickly when illuminated, on the average as 5 is to 4. As little reliance can be placed on these experiments, a quadrant electrometer was charged, and the graphite rods, separated by sulphur, inserted between the binding screws, so that the negative quadrant was connected with the positive one oe the cape (1°5 cm. long, 1 mm. thick, and 1 mm. broad). The electrometer was charged to the same potential in each experi- ment in a series and allowed to run down for a certaim time. Sun- light was allowed to fall on the sulphur, but shaded from the rest of the apparatus; when not required the ordinary window blind was drawn down. Of course the electrometer and sulphur were protected from induc- tion by surrounding bodies by wire screens. The following three series of readings were taken on different days, and in one or two cases clouds interfered with the experiment, espe- cially in No. 8, when the light was considerably shaded by cloud. a Resistance and other Properties of Sulphur. 145 Scale deflection Ti Fall in scale | at the prec divisions. beginning. minutes. Ist series (1) . 180 30 20 (2) . ‘ 15 20 (3) . # 35 18 2nd series (4). 300 15 25 (5). Ks 17 25 (6). 15 20 (7). ae 15 19 (8). ak 15 20 3rd series (9). 200 15 14 (10) F 15 17 (11) ie 16°5 16 (12) ” 15 10 (13) : 15 10 ! The first and second series were alternated dark and light in the same set of experiments to see that no permanent change was pro- duced and mistaken for the effect sought. In the first the time varied and the deflections were allowed to fall the same distance; in all the others the time was the same and the fall varied. The method of performing the experiments made 1t possible that the effect might be produced by the heat of the sun and not by the light. The variation in temperature observed on a delicate thermometer was about 1° C. ‘To eliminate the effect of heat, a long series of observa- _ tions was made in the dark, whilst the temperature was raised slightly by placing a Bunsen flame 4 or 5 inches away from the screen pro- tecting the sulphur, and the heat radiated by placing an iron spiral in it, then one of copper, and lastly a fine clay tile. The range of temperature was 15:2° C. to 17-1° C. in the first ten experiments, in which the heated ones fell rather more slowly than those at a lower temperature. In the next seven observations the range was 148° C. to 18° C., the fall being exactly the same in each. There yet remained the possibility that the lght falling on the wires which held the rods caused the charge to escape more quickly into the air. When, however, the sulphur was removed, the effect produced by the light on the portions of wire exposed to its influence was too small to produce any change in the rate of fall. Hence it appears that although selenium is the body most sensitive to the action of Jight, it shares its property with its neighbours, and the three elements (constituting the same group), sulphur, selenium, and tellurium, are all similarly acted upon, furnishing another example VOL. XLVI. L 146 Dr. J. Monckman. The Specific of the importance and beauty of the law which classified them together. During the course of this work I have often consulted Professor J.J. Thomson, F.R.S., and received many valuable suggestions and some corrections, for which I desire to acknowledge my obligation. Addendum. May 22, 1889. It having been suggested that the passage of the current at high temperatures through roll and precipitated sulphur was caused by the presence of impurities, and not by any change in the properties of the sulphur itself, that some of the impurities distil over with the element, especially sulphuric acid, compounds of mercury and selenium, whose presence would be quite sufficient to account for the effects given by ‘he specimens used in the previous experiments, it was necessary to btain the purest possible specimens of sulphur, and with this object no pains have been spared. As there also arose the question whether a liquid, being neither a metal nor an electrolyte, could conduct an electric current, it appeared to be preferable to try various methods of purification, and to compare the results obtained. To make this comparison more valuable, the methods should not be simply variations of the one system, but proceed upon distinct lines, so that any impurities, left after all possible care had been used, should be different in the different specimens, and in the measure- ments there would appear the effects due te distinct bodies, and if so, give some indication of the presence, in one or other of the portions used, of some foreign body changing the electric properties of the melted sulphur differently from the cases in which that particular body could not possibly occur. Three methods of purification were employed :— Ist, solution, crystallisation, and distillation; 2nd, distil- lation, without solution, in an atmosphere intended to remove hydrogen compounds; 3rd (pure soluble bodies only were used, easily tested chemically), precipitation, washing with water, and distillation. In numbers 1 and 2, foreign bodies acting upon sulphur were added and afterwards removed; they were different bodies, and if not per- fectly removed might be expected to change the conductivity accord- ing to their own individual properties. In number 3 no such body was introduced. Consequently, if 1, 2, and 3 were alike in their resistances at various temperatures, it must arise from changes in the one body common to all three, namely, sulphur. Before giving further particulars of these three methods, I wish to describe experiments undertaken to prevent the electrodes and the containing vessels from spoiling the liquid after it had been purified. Resistance and other Properties of Sulphur. 147 In the course of the work it was found that the vessels in which sul- phur was boiled for any length of time were attacked. Ordinary test-tubes invariably gave way, becoming coated internally with a thin black film, which remained fixed to the glass. Ordinary tubes and glazed porcelain under the same circumstances showed a number of dark spots, which proved to be sulphide of iron; even combustion-tubing did the same thing. All these experiments had been made with the flame of a bunsen lamp acting directly upon the vessel containing the sulphur, and it appears that no material will resist the attack of that body under such conditions. It seems to be caused by over-heating a portion of the vessel from which the liquid has been separated by the vapour, when bubbles are formed. When the liquid falls back upon this over- heated surface, chemical action commences. Further experiment, however, showed that when combustion-tubing, or retorts of Boliemian glass, are protected from the direct action of the flame, sulphur may be boiled or distilled in them without any action whatever taking place. Investigations were also made on the nature of the electrodes, by means of which a current could be made to pass through sulphur, and upon the best form to be used to avoid chemical action. In the previous work I used ordinary thin platinum wire, and failed to get a current to pass. : In repeating this experiment I used a wire of one millimetre diameter, which had been exposed to great heat for a considerable length of time, and found that the current passed readily. The same thing took place when some thin, very hard, carbon rods were substituted for the platinum. The liquid was, however, dirtied by particles of carbon torn away from the rods, and consequently I have not considered the numbers obtained worthy of being recorded, but simply the fact that with hard carbon rods for electrodes, sulphur will conduct; probably electric lamp filaments may prove good enough to resist Ee aeeee rapier if not too thin for the purpose. To test the effect of sulphur upon the electrodes, the containing vessel was placed in a second one, half filled with mercury, which was kept boiling several hours; this produced a steady temperature of 300°. The platinum electrodes were immersed in the liquid, and after allowing them to remain undisturbed until the whole mass had assumed the proper temperature, measurements were taken at stated intervals. The method was to use a steady electromotive force, with the sulphur in circuit, and a high resistance galvanometer. The numbers given below show a conductivity increasing with the time of contact between the electrodes and the hot aipiace After the experiment I found that the platinum was considerably discoloured. 148 Dr. J. Monckman. The Specific Table showing the action of Heated Sulphur upon Platinum Electrodes. Deflection produced After an by a constant exposure of — electromotive force. GO Aninates:».) bugs 22 scale divisions. O00. bs eae eee eee 29 3 120 <0 salt Si Hab ee eee 32 4 VAS ie 5 spel ies ed had yt re 39 - BOO 4 aes Recs Gh: dace ee te 40 ~ TTA aah ENG: arth 43 é DTS hs bb ae athe AA Lastly, the same graphite rods were used as in the previous experi- ments. These electrodes had been repeatedly exposed to high temperatures, and also boiled many times in sulphur. After being kept at temperatures varying probably not more than from 400° C. to 440° C. during five hours, the conducting power of the liquid was practically the same as at first. Thus, at.12.50 p.m. (boiling) the deflection was 290 scale divisions. The flame was then slightly reduced, and at— PEeQO par fe ME 260 scale divisions. = PS har el es ae 150 - The flame was then raised again, and at— Ay SOB Me ore a eee 220 scale divisions. 5.30 P.M. (boiling) 280 4 5.00 P.M. ae 280 is New graphite electrodes were next tried, and found to discolour the sulphur considerably ; but the resistance was increased. In all cases the current passed. The objection to using the same electrodes, even after using great care in cleaning them in the different liquids, and in that way contaminating them, and the impossibility of getting new ones that would do without previous boiling in sulphur, caused me to abandon their use altogether, and to depend upon a short exposure of platinum instead. The conclusion, determined by the work described, was that using combustion-tubing for boiling and well- cooked graphite electrodes, the change produced by chemical action is practically nothing, even after boiling several hours, if the containing vessel be protected from the direct flame, and that in the case of platinum electrodes, it tne observations are taken immediately they are inserted into the liquid, the action is slow enough to allow measurements to be taken without fear of error. Resistance and other Properties of Sulphur. 149 Purification of the Sulphur. In the first method, for which I am indebted to Dr. Ruhemann, of the Chemical Laboratory, Cambridge, bisulphide of carbon was purified by being shaken with a little mercury and allowed to stand. It was afterwards distilled over dry calcium chloride. These opera- tions were repeated until the liquid was separated from other sul- phides and from water. It was then saturated with sulphur and half of the liquid distilled off On cooling, crystals of sulphur formed. These were removed and washed with fresh bisulphide to remove any impurities that might have been left on their surfaces by the evapora- tion of the adhering mother-liquid. They were then carefully broken up and placed in a vacuum to remove as much of the bisulphide as possible before distilling. After remaining so for several days, they were distilled im vacuo several times, the first portion coming over, and that portion remaining behind being rejected in each case. The substance thus produced was of a beautiful light yellow colour, and melted into a perfectly clear, transparent liquid, about the colour of olive oil; at higher temperatures it assumed the tint of port wine. No traces of sulphuric acid, nor of chlorides, could be found, and the absence of selenium was proved in the original substance. ! The only objection to this method of working is the presence of a body whose solvent power for sulphur is so great, and the possibility that the last traces are not removed even by repeated distillations in vacuo. The second method consisted in distilling precipitated sulphur in an atmosphere of chloride of sulphur, which removes hydrogen com- pounds. After repeating this several times, it was distilled in vacuo. As before, the middle portion only was retained. This method has been found to give good results in the hands of some experimenters, but I found very great difficulty in removing the chloride, bemg obliged to reduce the body to a fine powder, and wash with water, and finding this insufficient, finally distilled over a few small pieces of pure zinc im vacuo, after which it was redistilled. This specimen was distilled altogether eleven times. The third method is the one used by Professor Threlfall, who takes hyposulphite of soda, free from selenium, and dissolves it in distilled water, then precipitates the sulphur by means of pure hydrochloric acid. The reaction is shown by the well-known equation— Na,S,0,+2HCl = 2NaC1+80,+H,0+8. All the substances produced, being either soluble in water, or gas evolved during the reaction, except the sulphur itself, can be washed out with pure water. L 2 150 Dr. J. Monckman. The Specific To avoid the addition of any objectionable body, no attempt was made to precipitate the sulphur from the sulphur dioxide, hence half the sulphur present was lost. Thus it will be ‘seen at once that a considerable quantity of the salt was required to produce a very small quantity of pure sulphur. 14 lbs. of the hyposulphite were dissolved, filtered, and decomposed by acid, then washed until free from salts and acids, dried, and distilled several times. When the residue appeared to be perfectly free from foreign matter it was repeatedly distilled in vacuo, the middle portion being removed. In this method the only solvent was water, and the other bodies produced could be tested for by delicate chemical reactions. I believe that the three methods described fulfil the requirements mentioned in an earlier portion of this paper, giving as pure sulphur as can be prepared, but at the same time, the bodies that may have escaped removal will differ in each specimen. Resistance and other Properties of Sulphur. 151 An improvement was introduced into the insulation of the elec- trodes. The platinum wires were fused into glass tubes from 12 to 14 inches in length. These were fixed into hard dry wood at a dis- tance of several inches from their ends. In this way the only part that can possibly conduct is removed further from the source of heat. The ends of the electrodes were flat plates, formed by bending the platinum wire upon itself three or four times, and then welding it together, also for greater security a strip of platinum-foil was welded to the back of each. The length of AB was 3: a cm., the width 0°45 cm., and the distance apart 0°2 cm. The tube in which the sulphur was boiled was formed by fusing up the end of a piece of combustion-tubing about 9 inches long, and wide enough to allow the glass tubes to be inserted in the Sete: without danger of touching the sides, and thus forming a circuit through hot glass. It was surrounded to the height of 3 inches by a copper tube, closed at the bottom, the intervening space being filled with sand. To avoid the chemical action which has been shown to take place when platinum is exposed for any length of time to sulphur at a high temperature, the electrodes were kept out of the liquid until every- thing was ready for taking a reading; they were then inserted, and the readings haying been taken as quickly as possible, they were removed. At the end of each set of experiments the wires were examined and found in every case to be free from any appearance of the dark film observed in the preliminary work. Before introducing them into the next specimen of sulphur they were ignited in the blowpipe-flame until perfectly clean. The method used was to place the sulphur in circuit with a battery and a high resistance galvanometer (R 11,700 ohms). In order to avoid chemical action it was considered better to reduce the number of observations and to commence with the boiling point. At 440° C. pure sulphur gave a deflection of 545 to 570 divisions. 350° C. 3 i y, 79 53 300° C. : : is 15 9 Those previously found, for precipitated sulphur at the same tem- perature, were 512, 73, and 15. Ihave therefore concluded that the two curves are identical. When the sulphur was removed from the circuit and a known resistance inserted, the calculated specific resistance was about one- fifth larger than that given by precipitated sulphur. 152 Dr. J. Monckman. The Specific ‘ I have calculated the specific resistance from the experiments, more as an indication of the magnitude of the resistance at the boiling point, and of the changes that take place as the temperature varies, than as an accurate determination of specific resistance. There are several circumstances which prevent the great accuracy usually expected in such cases. First the extreme difficulty of obtain- ing a steady temperature without exposing the electrodes to chemical action. Thus if the readings be taken at 350° C., by using a bath of boil- ing mercury it requires a considerable time to get the whole mass of sulphur to this temperature, the sulphur being a very bad conductor of heat and there being no agitation to assist. When the whole is steady and the electrodes are introduced, they cool the portion in contact with them, and it is necessary to wait until the temperature rises again. Hence arises an uncertainty, we may take it before the temperature is fully recovered, or we may delay too long and allow chemical action to commence. The same objection applies, in some measure, to boiling sulphur, but as the whole is in motion the recovery is quick. Great care is necessary to prevent bubbles of gas rising up between the electrodes and so increasing the resistance. Some error might also arise from the size of the electrodes, 3°30 cm. x 0°45 cm., distance 0°'2cm. They were as large as the quan: tities of pure sulphur obtained by nearly three months’ work enabled me to use them. With these reservations I give the specific resistance of melted sulphur, calculated from experiments with the three specimens men- tioned. Specific Resistances. No.1. At 440°C....... 78 megohms. 2. LoS aes 8:0 r 3, Fe MPa ti ngs 73 2 263. At3o00 Ce. 3.27 968 ‘s sp Go OD MOE 282°5 3 Bowling Point. An objection has been raised to the curve found in the experi- ment on the boiling point of sulphur under varying pressures, on the ground that the vapour-pressure rises in a straight line, and that, therefore, the boiling point would give a straight line also. It is usually stated in text-books that when the vapour-pressure of a liquid becomes equal to the pressure on the surface of that liquid it immediately begins to boil. If this is a scientific fact, the objec- Resistance and other Properties of Sulphur. 153 tion urged is good, and the vapour-pressure of any liquid and the boiling point of that liquid must always be on the same line. I think, however, that it is never absolutely correct, and sometimes it is very far from being true. If we suppose a thin film of the liquid to be acted upon with a downward pressure produced by the air and an upward force pro- duced by its vapour-pressure, these two forces, by hypothesis, equal and opposite in direction, can produce no motion in the film. Let the force necessary to produce this motion be called (a). Besides the mere upward motion of the film in a bubble, there is an expanding action which draws out the substance of the bubble, and is resisted by it with force depending upon the nature of the liquid. let this be called (0). Finally, there is a certain amount of force required to burst the particles of the liquid apart when the bubble begins to form. Let this be (c). We have, therefore, when bubbles are formed in any liquid, a force equal to the pressure on the surface of the liquid together with a + 6+ ¢. If the viscosity of the liquid remains the same through the whole range of temperature, a + b + c¢ will remain the same, and the line for vapour-pressure and that for boiling point will be parallel, but if instead of this, the liquid changes from being a liquid as mobile as water to a thick viscous body, so stiff that the vessel containing it may be inverted without one drop of the substance being lost, a+ b + c wil! change also, and the two lines will not be parallel. The forces a + 6 + ¢ will bea function of the viscosity. To test the truth of this reasoning, I carefully repeated the experi- ments, and found the results to agree with those previously obtained. At the same time, besides noting the pressures at which the bubbles began to form on the surface of the liquid at various temperatures, I observed the pressures at which these bubbles burst, and found that there was a considerable difference. Up to 280° C. it was 4 mm. of mercury, while at 296° C. it fell to 1 mm., or A+B = 4mm. of mercury up to 280° C. A+B=1 . 5 296° C. I did not attempt to measure the force C, but I think it probable that itis much greater than A+B, and that the variation of these (A+B+C) in sulphur explains the form of the line found. The sulphur molecule is known to undergo various changes, at one temperature containing six atoms, while at another only two enter into its formation. What are the molecular modifications that take place when it cools to a liquid, or when it assumes a semi-fluid state VOL. XLVI. M 154 Dr. E. Roux. [May 23, and at last turns back again to liquid, we do not know. But when one of these changes is accompanied by a corresponding one in chemical activity, it appears to mark a point at which the complex molecules are being broken into others of less complex structure. As this is the temperature at which the conductivity changes, I am inclined to suspect that the current is carried by the simpler mole- cules, as they break apart and recombine, acting, to a certain extent, the part of the different elements in an ordinary electrolyte. Sup- posing this to be the solution of the question, other elements that undergo similar molecular changes should give indications of a like nature, and I am at present engaged in work with the object of seeing if it is so. May 23, 1889. Professor G. G. STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The Croonian Lecture was delivered as follows :— CrooniAN Lrcoture.—‘ Les Inoculations Préventives.” By Dr. E. Roux, Institut Pasteur, Paris. Delivered May 23,— MS. received May 23, 1889. MESSIEURS, Au mois d’Aott, 1881, M. Pasteur faisait connaitre aux membres du Conerés Médical International, réuni 4 Londres, les récents travaux de son laboratoire sur les inoculations préventives du choléra des poules et du charbon. Huit années sont presqu’écoulées depuis cette époque. Qu’est devenue lceuvre commencée alors, a-t-elle justifié les espérances quelle faisait naitre? Quelle place ont pris dans la science les principes nouveaux qui venaient d’y étre introduits? C’est ce que M. Pasteur devait exposer devant vous aujourd’hui. Mais l’état de sa santé ne lui a pas permis de répondre 4 l’honneur que lui avaient fait le Président et le Conseil de la Société Royale, en le conviant a faire la lecture de cette année. II a proposé au Président et au Conseil de votre Société d’accepter que je parle en son nom. Je ne saurais, Messieurs, vous parler, comme |’aurait fait M. Pasteur, de ces inoculations préventives qu’il a inventées, et je crains bien d’augmenter aujourd’hui, par mon discours, le regret que vous cause déja son absence. Je n’ai qu’un titre qui puisse expliquer que je sois a cette place, 1889. | Les Inoculations Préventives. 155 cest celui de collaborateur de M. Pasteur. J’ai eu, en effet, avec MM. Chamberland et Thuillier, ’honneur d’étre associé aux travaux sur la prévention des maladies contagieuses, et mon excuse pour oser prendre la parole devant vous est que j’ai vu les choses dont je vais parler. Beaucoup de maladies infectieuses ne récidivent pas. Le plus souvent on n’a qu’une fois la variole, la rougeole, la fievre typhoide etc. Une premiére atteinte, méme légére, met a l’abri de ces maladies pour un temps plus ou moins long. Cette observation de la non- récidive des maladies infectieuses a conduit a linoculation préventive. Au lew dattendre d’étre frappé a Vimproviste par la maladie, souvent pendant une épidémie trés meurtriére, dans des conditions défavorables a la résistance, on a cherché a prendre cette maladie a un moment choisi, avec toutes les précautions capables d’en diminuer le danger. A la contagion naturelle, imprévue, et sur laquelle on n’a pas d’action, on a substitué la contagion artificielle, préparée de fagon 4 donner l’immunité avec le moins de risques possibles. C’est contre la variole que l’on a eu recours pour la premiére fois a Vinoculation préventive. En effet, une expérience involontaire et trop souvent renouvelée, avait appris que le liquide de la pustule variolique est virulent, c’est-d-dire que cette lymphe varioleuse intro- duite dans le corps par une blessure de la peau, communique la maladie 4 une personne qui ne l’a pas eue encore. L’inoculation de la variole était donc facile. II suffisait pour la réaliser de la piqure d’une lancette chargée de pus varioleux. Dans la pratique, on recherchait un cas de variole bénigne et dans les pustules on puisait un virus, supposé peu actif, mais capable de conférer Pimmunité a ceux qui le recevaient. Vous savez, Messieurs, qu’elle extension prit Ja variolisation, qui était loin cependant d’étre inoffensive, puisque Vinoculation que l’on croyait devoir donner une maladie légere procurait souvent une maladie grave, parfois méme mortelle. Aussi, combien grand a été le progrés di 4 Jenner qui a remplacé la variolisation par la vaccination. A l’inoculation d’une maladie grave, Jenner substituait celle d’une maladie toujours inoffensive et qui met efficacement a l’abri de la variole. Depuis le commencement de ce siécle nous jouissons de l’inappré- ciable bienfait de la vaccination Jennérienne, et cependant nous n’en avons pas encore pénétré le secret. Quelle relation y a-t-il entre la vaccine et la variole? Pourquoi la vaccine, maladie du cheval et de la vache, inoculée 4 homme, le préserve-t-elle de la variole? Le virus vaccin est-il le virus modifié de la variole, ou bien variole et vaccine sont-elles deux maladies différentes? Il semble que ces questions soient faciles 4 résoudre, puisque l’on peut expérimenter sur la variole et la vaccine. Posées depuis Jenner elles sont encore sans réponses précises. La grande découverte Jennérienne, si bien faite M 2 156 Dr Ee Roms [May 23, pour éveiller les espérances, est restée unique en médecine. Née d’une observation heureuse, merveilleusement développée par un génie aussi patient que pénétrant, elle était, a Vépoque ou elle a été faite, si en avance sur la médecine, qu’aujourd’hui aprés tant de progrés, nous ne pouvons qu’en soupconner la véritable interprétation. Jenner nous a montré, par un extraordinaire exemple, que Von peut préserver d’une maladie mortelle par l’inoculation d’une maladie bénigne, mais i] ne nous a pas donné de méthode pour nous conduire a4 la prévention des autres maladies infectieuses. La découverte de l’atténnation artificielle des virus nous fournit, au contraire, une véritable méthode d’inoculation préventive qui a déja donné une suite ininterrompue de résultats heureux, bien qu’elle date & peine de quelques années. Comme tous les autres progrés accomplis récemment dans la connaissance des maladies virulentes elle a pour origine les recherches de M. Pasteur sur les fermentations. En nous dévoilant la nature des ferments, M. Pasteur nous a appris celle des virus. Comme la levure alcoolique et la levure lactique, les virus sont des étres vivants, des microbes comme on dit aujour@’hui. De méme que le développement de la levure, dans un liquide sucré, produit la fermentation alcoolique, de méme celui des microbes dans le corps produit la maladie infectieuse. Les procédés qui ont réussi pour obtenir la culture des microbes- ferments 4 Vétat de pureté sont ceux qui ont permis la culture pure des microbes-virus en dehors de l’organisme. La condition expresse pour réussir ces cultures, c’est d’agir avec pureté, c’est-a-dire, d’éviter Vintroduction des germes étrangers qui sont partouf autour de nous. Une technique bien établie maintenant, rigoureuse en méme temps que trés simple, permet d’obtenir ce résultat. Puisque les virus sont des étres vivants que l’on peut entretenir en cultures artificielles, et quils ne se distinguent des autres plantes microscopiques que par la propriété qu’ils ont d’envahir le corps de homme et des animaux, ne serait-il pas possible de les modifier par la culture comme on modifie les autres plantes? Ne pourrait-on pas par exemple les priver des qualités qui les rendent redoutables ? Modifier les virus par des conditions de culture spéciales, telle est Vidée de M. Pasteur, idée féconde d’ou est sortie la suite de décou- vertes que je vais vous exposer. C’est en étudiant une maladie des volailles appelée “choléra des poules,” que M. Pasteur a obtenu pour la premiére fois un virus atténué. Cette maladie est si meurtriére pour Jes lapins, les poules, les pigeons et les oiseaux en général, qu’on lui a donné le nom de choléra. Elle est causée par le développement, dans le corps des animaux qui en sont frappés, d’un microbe trés petit, en forme de batonnet, a bouts arrondis, presque aussi large que long. La photographie projetée sur l’écran nous montre l’image au microscope d’une gouttelette du sang 1889. | Les Inoculations Préventives. IUD d’une poule qui a succombé a la maladie spontanée. Vous voyez, entre les globules du sang, les petits batonnets qui sont la cause de la maladie. Il n’y a pas que le sang qui contienne le microbe; tous les tissus sont envahis par lui, Les intestins en renferment une grande quantité, de sorte que les déjections des poules malades peuvent répandre la maladie. C’est en picorant sur le sol souillé que les volailles saines sont contaminées. Si Pon introduit, sous la peau d’une poule en bonne santé, une trace du sang d’une poule qui vient de succomber au choléra spontané, Vanimal inoculé tombe bientét malade; il ne mange plus; il tient ses plumes hérissées, ses ailes pendantes, et 11 semble accablé par une somnolence invincible. a mort survient souvent en moins de douze heures. Le sang de la poule qui a succombé a linoculation expérimentale est envahi par le microbe, absolument comme le sang des volailles qui meurent a la suite de la contagion naturelle. Le choléra des poules nous apparait donc comme une maladie con- tagieuse, inoculable, dont le virus est contenu dans le sang des animaux qui en sont frappés. La culture du microbe qui se fait si facilement dans le sang des animaux peut aussi étre obtenue en dehors del’organisme. Au moyen d’un fil de platine, d’abord chauffé au rouge puis introduit dans le coeur ou dans un vaisseau d’une poule morte du choléra, portons une trace de sang dans un flacon comme celui-ci, qui contient un peu de bouillon de poule légérement alcalin et parfaitement limpide. Plagons ensuite ce flacon dans une étuve 435°. Au bout de quelques heures le bouillon est troublé, et le trouble est di au développement du petit microbe du choléra des poules. Au microscope chaque gouttelette du bouillon nous montre une quantité innombrable de petits batonnets immobiles, semblables a ceux qui étaient contenus dans le sang qui a servi de semence. Une quantité infiniment petite de cette premiére culture, déposée dans un nouveau flacon de bouillon, donnera une seconde culture. Par des ensemencements successifs, on pourra produire des générations de notre microbe aussi nombreuses qu’on le voudra. Chaque goutte de ces cultures, de la vingtiéme aussi bien que de la premiére, tuera avec tous les signes du choléra la poule a laquelle on Yinoculera. Cette expérience nous donne la preuve décisive que le virus de la maladie est bien le microbe contenu dans nos cultures, et puisque nous savons préparer i vitro, dans des conditions bien précises, des quantités de virus du choléra aussi grandes que nous le désirons, nous sommes vraiment outillés pour l’étude de cette maladie. Laissons a 35°, au contact de lair pur filtré a travers le tampon de coton qui ferme le flacon, une de ces cultures, si active qu’elle tue toutes les poules auxquelles on linocule. Chaque semaine, prélevons un peu du contenu de ce flacon, et essayons sa virulence sur des poules en bonne santé. Pendant les premiéres semaines de 158 Dr. E. Roux. [May 23, Vexpérience, toutes les poules inoculées succombent; mais, aprés un temps plus long, un changement parait survenir dans la virulence; toutes les poules ne meurent plus quand on leur injecte sous la peau cette culture plus ancienne. Quelques-unes se rétablissent aprés avoir été trés malades. A mesure que le temps s’écoule, l’activité du virus diminue et le nombre des volailles qui résistent aprés Vinoculation devient de plus en plusgrand. En continuant l’expérience, il arrivera un moment, apres deux mois de séjour a l’étuve par exemple, ot notre virus, d’abord si meurtrier, non seulement ne tuera plus aucune des poules inoculées, mais encore ne leur causera aucun malaise apparent. Ht cependant, le virus n’est pas mort, puisqu’il pullule dans Je milieu nutritif ou on le séme. Dans cette culture nouvelle, il ne reprend aucune virulence. Les cultures filles ont sur les poules exactement Vaction qu’avait la culture mére au moment ou celle-ci a fourni la semence. Les propriétés nouvelles du virus, celle d’étre devenu inoffensif pour les animaux qu il tuait tout dabord, peuvent done se perpétuer dans des générations successives. En faisant des ense- mencements de la culture mere a des dates convenables, on obtiendra toute une série de virus d’activité décroissante, capables de donner aux animaux, soit une maladie mortelle, soit une maladie grave, soit une maladie sérieuse, soit une maladie inoffensive. A quelle influence est due cette diminution graduelle de la viru- lence? mocule un second, celui-ci succombera plus rapidement encore. On peut ainsi faire passer le rouget par une série de lapins, et chose surprenante, dans les expériences de MM. Pasteur et Thuillier, a mesure que la virulence s’exalte pour le lapin elle diminue pour le pore. Si bien, qu’aprés un nombre suffisant de ces passages, le virus du rouget est atténué pour le pore. Il est devenu, pour cet animal, un vaccin véritable capable de le mettre a labri de la maladie mortelle. Apres cet exemple, ne peut-on pas se demander ce qui adviendrait de certaines maladies humaines si on les faisait ainsi passer a travers un grand nombre d’animaux d’espéces différentes? Ces passages n’ont-ils pas eu lieu dans la nature 4 notre insu, et Vidée que la vaccine est la variole modifiée par le passage sur le cheval et la vache ne trouve-t-elle pas dans ces faits comme un nouvel appui ? Aprés tous ces travaux sur le choléra des poules, le charbon et le rouget, c’est a prévenir la rage que M. Pasteur a consacré ses efforts dans ces derniéres années. Que savions-nous sur la rage, lorsqu’en 1880 1’étude de cette maladie fut commencgée au laboratoire de M. Pasteur? Nous savions que la 164 Dr. E. Roux. [May 23, des animaux enragés et que c’est par leurs morsures que ceux-ci trans- mettent la maladie. Nous savions encore que la durée de l’incuba- tion varie de quelques jours a plusieurs mois. A ces notions se bornaient nos connaissances précises surlarage. Cependant beaucoup d’expériences avaient été faites sur cette maladie, mais deux circon- stances rendaient l’expérimentation difficile et les résultats incertains. L’inoculation de la salive d’un animal rabique 4 un animal sain, ne | donne pas toujours la rage; beaucoup de ces imoculatious restent | sans effet. Parmi les animaux qui prennent la maladie, quelques-uns deviennent enragés aprés un temps si long que cette attente pro- : longée met la patience de l’expérimentateur 4 une dure épreuve. La salive de ’animal enragé est un virus infidéle, parce qu’elle renferme une quantité de microbes variés, qui, introduits sous la peau en méme rage est contagieuse, que le virus rabique est contenu dans la salive | | temps que le virus rabique, empéchent le développement de celui-ci et le font disparaitre dans une sorte de concurrence vitale. Le premier progres a accomplir était de trouver une source de virus rabique non souillée de germes étrangers. Tous les symptémes de la rage relévent du systéme nerveux et lVidée que le virus rabique doit exister dans les centres nerveux s’impose a l’esprit. Les tentatives | faites pour montrer que la substance nerveuse d’un chien rabique j est virulente n’avaient cependant pas réussi, parce que dans les | manipulations que l’on faisait subir a cette matiére nerveuse pour | Vinoculer on y introduisait les germes étrangers qu'il fallait précisé- ment éviter. En inoculant, avec pureté, de la moelle épiniére, du | cerveau, des nerfs d’un animal mort de rage, M. Pasteur montra que le véritable siége du virus rabique est dans la substance nerveuse. Une parcelle des centres nerveux d’un chien rabique, insérée sous la peau d’un chien en bonne santé, lui communique la rage, et cela plus r strement que la salive la plus active. Cette démonstration permettait | de faire un pas décisif dans |’étude de la maladie. Puisque le virus rabique se. trouve dans les centres nerveux et que tous les symptémes de la rage relévent du systéme nerveux, n’était-il pas naturel de penser que la rage ne se manifeste que lorsque les centres nerveux sont envahis par le virus, et que la période d’incubation est le temps employé par le, virus pour aller du lieu d’inoculation a Vaxe cérébro-spinal et y faire sa culture? Si donc on porte ce virus tout d’abord dans Je tissu nerveux, 1a ot il doit se cultiver, l’incuba- tion devra étre abrégée et la rage devra apparaitre 4 coup sur, parce- que le virus ne pourra plus s’égarer ou étre détruit dans un long trajet. L’expérience, Messieurs, a confirmé ces vues de l’esprit, et je.vois | encore ce premier chien inoculé 4 la surface du cerveau, par trépana- | tion, et qui prit la rage aprés une incubation réduite 4 quatorze jours. | Tout chien, en effet, qui regoit sous la dure-mére un peu de la moelle | £339. |. - Tes Inoculations Préventives. 165 ou du cerveau d’un animal enragé prend strement la rage et dans un délai qui, en général, ne dépasse pas dix-huit jours. Nous voici done désormais 4 l’abri des incertitudes de l’inoculation sous la peau et des ennuis des longues incubations. Aussi, apres cette expérience, les progrés se multiplient dans l'étude de la rage, on prouve que le virus existe dans les nerfs et que par cette voie il va de la plaie au cerveau et a la moelle, qwil peut aussi dans quelques cas étre trans- porté par la voie sanguine. On comprend que les manifestations rabiques sont aussi variées qu’il y a de foyers fonctionnels divers dans les centres nerveux, que les symptomes de la rage au début dépendent de la région tout d’abord abordée par le virus, enfin l’on reconnait qu’il existe des formes de rage jusqu’alors passées inapercues et différentes des types classiques. L’opération de la trépanation est par elle-méme inoffensive, quand elle est faite avec des précautions antiseptiques. LHlle réussit sur le lapin avec la méme streté que sur le chien. Si on pratique l’inocula- tion de la rage, par trépanation, sur une série de lapins, en se servant du bulbe de l’animal qui vient de mourir pour inoculer le lapin suivant, on voit que la durée de l’incubation qui était de quatorze a dix-huit jours au début de l’expérience va en diminuant. Hille devient de plus en plus courte 4 mesure que le nombre des passages est plus grand ; aprés une centaine de ces inoculations successives, elle n’est plus que de sept jours, puis elle arrive a n’étre plus que de six jours. Alors elle ne diminue plus; le virus rabique, par cette culture répétée sur le ‘Japin, semble avoir atteint sa virulence maximum pour cette espéce ; on dit qu il est fixé. C’est de ce virus-fixe que M. Pasteur a tiré le virus-vaccin de la rage, par un procédé qui sur plus d’un point rappelle celni déja employé pour atténuer le choléra des poules, le rouget et le charbon. Dans un flacon a tubulure inférieure, contenant dans le fond des fragments de potasse caustique et fermé par des tampons de coton, suspendons une moelle rabique de lapin de passage. Cette moelle qui renferme en abondance le virus-fixe va se dessécher 4 l’abri des poussiéres, et au contact de l’air 4 23°, car nous avons soin de la main- tenir 4 cette température. $i chaque jour nous prélevons un fragment de cette moelle pour l’inoculer a la surface du cerveau d’un lapin, nous constaterons qu’a mesure que la moelle se desséche dans lair, elle perd sa virulence. Au bout de cing jours de dessication elle ne tue déja plus que quelques-uns des lapins quil’ontregue. Au bout de quatorze jours environ elle se montre tout-a-fait inoffensive, aprés avoir passé les jours précédents par des virulences graducllement décroissantes. Maintenant que nous avons des virus rabiques atténués, injectons chaque jour sous la peau d’un chien un fragment de moelle atténuée broyée dans l’eau pure, en ayant soin de commencer par l’injection de la moelle inoffensive de quatorze jours et de continuer le second jour par 166 Dr. E. Roux. ° [May 23, Vinjection de la moelle de treize jours, puis le troisiéme jour par Vinjec- tion de ia moelle de douze jours jusqu’a l’imoculation de la moelle de zéro jour, c’est-a-dire de la moelle non atténuée, de la moelle dont la virulence est mortelle. Ce chien ne succombe pas 4 la rage, bien plus, nous pouvons l’éprouver en lui inoculant dans le cerveau le virus rabique le plus actif, 11 ne devient pas malade. Ht cependant nous savons que inoculation intra-cranienne est un procédé certain pour donner la rage. Les injections de moelles desséchées qu’il a subies Ini ont donc conféré Vimmunité. L’expérience peut étre recom- mengée autant de fois qu’on le désire, le résultat sera toujours le méme. les chiens qui ont regu sous la peau la série des moelles de quatorze a zéro jours ne prennent plus la rage, ni a la suite des mor- sures de chien enragé, ni autrement. L’état réfractaire a été ainsi obtenu en une quinzaine de jours. D’ordinaire, la rage ne se céclare chez un chien mordu par un animal enragé, quaprés un délai qui le plus souvent dépasse un mois. Ne serait-il pas possible de profiter de cette longue incubation et de donner l’immunité contre la rage avant l’apparition de la maladie ? Des chiens furent mordus par des chiens enragés, ou furent inoculés sous la peau avec du virus rabique; les uns furent conserves comme témoins, les autres furent soumis aux injections préventives des moelles desséchées de virulence croissante ; aucun de ces derniers ne prit la rage, tandis que les premiers moururent en grand nombre de la maladie caractérisée. I] était done possible de prévenir la rage apres morsure. Malgré tous les résultats favorables obtenus sur les animaux, appli- quer 4 Vhomme mordu la méthode éprouvée sur le chien était assurément faire un pas audacieux. On sait par quelles sollicitations, par quels conseils autorisés M. Pasteur fut décidé a le franchir. Le 6 Juillet, 1885, ’enfant Meister mordu cruellement par un chien enragé, subis- sult la premiére inoculation antirabique. O’est ]4 une date qui mérite d’étre rappelée ; elle marque non seulement dans histoire du laboratoire de M. Pasteur, mais aussi dans celle dela science. Je ne dirai pas longuement comment a la suite de ce premier essai heureux, les mordus affluérent de toute part au laboratoire, comment depuis cette époque, chaque mois 150 personnes environ viennent réclamer Vinoculation antirabique. Quelques-uns d’entre vous, Messieurs, ont assisté a ces inoculations, ils ont vu avec quel soin sont préparées les émulsions des moelles atténuées, pour éviter l’introduction de tout germe étranger. Les injections se font dans la région du flane, a droite et a gauche alternativement ; elles sont répétées pendant quinze jours. Pour les morsures ordinaires on commence par l’injection de la moelle de quatorze jours et on s’arréte a4 celle de trois jours. Pour les morsures graves qui siégent a téte, on fait un plus grand nombre d’in- oculations et on arrive plus rapidement aux moelles récentes, parce qu’on — , 1889. ] Les Inoculations Préventives. 167 n’a pas été longtemps 4 apprendre que, contre ces morsures, il fallait un traitement plus actif. Depuis le début des inoculations antirabiques 6870* personnes ont été traitées dans le seul Institut de Paris.+ Parmi elles, beaucoup avaient des morsures graves. La preuve que l’animal mordeur était enragéa été fournie soit par ’expérimentation soit par l’examen vétér1- naire dans plus de &0 pour cent des cas. La mortalité par la rage, sur ces personnes traitées, est de 1 pour cent environ; elle est trés faible si on la compare a celle de 14 pour cent qui suit d’ordinaire les morsures de chiens enragés. Qui aurait pu croire que ce nombre si petit d’insucceés serait l’occasion d’attaques violentes contre la pratique des inoculations antirabiques? Ces inoculations ont subi les reproches les plus divers: on les a accusées d’étre inefficaces, et des contradicteurs avancaient que les bons résultats publiés étaient dis a cette circon- stance que le traitement dans presque tous les cas était appliqué a des personnes mordues par des chiens non-enragés. La statistique, disaient-ils, montre qu’eu France il y a autant de morts par rage depuis invention du traitement antirabique qu’il y en avait avant. Cette assertion était celle d’hommes mal informés, qui prenaient pour des statistiques complétes des documents reconnus insuffisants par ceux mémes qui les publiaient. Quant 4 la preuve de l’efficacité du traitement, elle se dégageait de l’examen des cas pour lesquels la rage de l’animal mordeur était prouvée expérimentalement, et surtout des résultats obtenus sur les personnes mordues ala figure. On sait en effet, qu’a la suite des morsures a la téte et a la face, la mortalité est de 80 pour cent au moins; chez les mordus de cette catégorie, traités a VInstitut Pasteur, elle n’atteint pas 4 pour cent. D’autres adversairves soutenaient que le traitement était dangereux et augmentait les chances de mort. De sorte que lon était en présence du fait singulier d’un traitement dangereux abaissant la mortalité dans des proportions inespérées. Ces premiers contradic- teurs n’avaient pour soutenir leur cause que la force de leurs raisonnements, car ils n’avaient fait aucune expérience. Mais d’autres survinrent qui, par des expériences, voulurent prouver que le fondement'méme de la méthode était mal établi, et que les inocula- tions antirabiques ne donnaient pas |’immunité aux chiens. Vous savez ce qu’il est advenu de ces prétendues preuves expérimentales ; elles ont été montrées inexactes, avec une autorité a laquelle on ne saurait ajouter, par les membres de la Commission Anglaise chargée de controler la méthode des inoculations antirabiques. Vous savez, Messieurs, de quels savants était composée cette Commission, et il * Chiffre a la date du 21 Mai, 1889. + Il existe 7 instituts antirabiques en Russie, 5 en Italie, 1 4 Constantinople, 1 A Barcelonne, 1 4 Bucarest, 1 4 Rio de Janeiro, 1 4 la Havana, 14 Buenos Ayres, 1 4 Mexico, 1 4 Vienne. oe 168 Dr. I. Roux. [May 23, suflit pour répondre définitivement 4 toutes les attaques de rappeler la conclusion de leur rapport, a savoir: que ‘‘ M. Pasteur avait trouvé une méthode préventive de la rage comparable a celle de la vaccina- tion contre la variole.’’* Peut-on espérer que la mortalité chez les personnes mordues et traitées deviendra nulle? Je ne le crois pas. Le plus grand nombre des personnes traitées, et qui ont succombé, ont pris la rage dans la quinzaine qui a suivi les inoculations. Cela tient 4 ce que chez elles, le virus a été apporté aux centres nerveux presqu’aussitot apres la morsure. L’expérience nous montre, en effet, que la rage éclate du douziéme au dix-huitiéme jour aprés Vinoculation sous- méningée ; elle nous apprend aussi qu’il est trés difficile de prévenir la rage chez les animaux ainsi inoculés, parce que la période d’incuba- tion est si courte que les virus atténués injectés sous Ja peau, loin de laxe nerveux, n’ont pas le temps d’agir. Dans les cas ot l’incubation est trés courte, le traitement peut donc étre inefficace; heureusement ces cas sont rares, méme aprés les morsures a la figure. Quant aux in- succes exceptionnels, qui surviennent aprés que le traitement a été com- plet, et que son effet a eu le temps de se manifester, il est difficile de se rendre compte de leur cause, ils tiennent peut-étre a une receptivité particuliére. Messieurs, ce qu'il y a de plus étonnant dans cette découverte de Vinoculation préventive de la rage c’est qu'elle a été faite sans que Von connaisse le virus rabique. Non seulement nous ne savons pas cultiver ce virus hors de l’organisme, mais, si nous admettons qu'il est un microbe c’est par analogie, car personne n’a encore pu montrer ce microbe d’une fagon certaine, Ht cependant ce virus inconnu a été atténué, chaque jour on le prépare a des états variés de virulence. A défaut de cultures artificielles in vitro, M. Pasteur a fait la culture du virus rabique sur le lapin. Ces cultures sur l’animal vivant s’obtien- nent avec une régularité si parfaite, une sécurité si grande, que chaque jour, pour le service des inoculations, elles sont préparées a l’heure dite, 4 état de véritables cultures pures. I] n’y a pas d’exemple plus saisissant de la puissance de la méthode expérimentale appliquée aux choses de la médecine que cette prophylaxie d’une maladie dont on ne connait pas la véritable cause. Cette série de découvertes sur la prévention des maladies con- tagieuses est l’ceuvre d’un seul laboratoire, et a été accomplie en moins de dix années; mais, quelque soit l’intérét pratique de sem- blables travaux, il est de beaucoup dépassé par l’importance du mouve- ment scientifique dont ils ont été le point de départ. Ils ont permis d’aborder Vétude si compliquée de Vimmunité, et je voudrais en * Les membres de la Commission Anglaise étaient :—MM. James Paget, Lauder Brunton, George Fleming, Joseph Lister, Richard Quain, Henry EH. Roscoe, Burdon Sanderson, Victor Hovsley, secrétaire. 1889. ] Les Inoculations Préventives. 169 finissant vous dire quelques mots des plus récentes acquisitions faites sur ce sujet. C’est la conclusion naturelle de cette lecture sur les inoculations préventives. Avant de rechercher comment l'état ré- fractaire est produit, demandons-nous comment on meurt dans les maladies infectieuses P Certains microbes, celui du charbon, par exemple, pullulent telle- ment dans le corps des animaux, qu’il y a dans le sang, au moment de la mort, plus de cellules parasites que de globules sanguins. Les bactéridies forment parfois des obstructions capillaires et agissent ainsi mécaniquement. Mais, comme toutes les cellules vivantes, les microbes ont leurs exigences vitales et on concoit, qu’avec leur nombre immense, ils doivent singuliérement modifier les milieux ou ils se développent. La bactéridie du charbon, qui est trés avide d’oxygéne, prend ce gaz aux globules sanguins et améne ainsi l’asphyxie des tissus. Mais les microbes sont surtout dangereux par les produits toxiques quils fabriquent. Une preuve frappante qu'il en est ainsi, nous est fournie par le bacille de la diphtérie. Ce bacille ne pénetre point dans l’intérieur des tissus, mais se cultive 4 la surface d’une muqueuse, pour ainsi dire en dehors du corps; cependant il améne la mort, parfois avec une effirayante rapidité. Dans ce cas il n’y a ni invasion du corps ni conflit de cellules; il y a empoisonnement au moyen d’un produit trés actif élaboré au niveau de la fausse membrane. II est difficile de trouver ces produits toxiques dans le corps d’un animal qui succombe i une maladie infectieuse. Le milieu si compliqué des tissus se préte mal 4 une semblable recherche; d’ailleurs, ces poisons y sont en trés petite quantité, car pendant que l’animal reste vivant il les élimine en partie. C’est dans les cultures, in vitro, qu'il faut s’exercer a découvrir ces produits de l’activité des microbes pathogénes. Lia premiére expérience faite sur le sujet est due a M. Pasteur. Pour savoir quelle était l’action sur les poules des produits élaborés par le microbe du choléra des poules dans les cultures, M. Pasteur injectait 4 ces animaux une grande quantité d’une culture absolument privée de microbes par filtration sur porcelaine. La poule qui avait recu ce liquide, dépourvu de tout virus vivant, devenait somnolente, laissait pendre ses ailes, hérissait ses plumes et pendant plusieurs heures présentait tous les symptdmes du choléra, puis elle recouvrait la santé. Cette expérience nous montre que les produits chimiques contenus dans la culture sont capables 4 eux seuls de provoquer les symptomes de la maladie, il est donc trés probable que les mémes produits sont préparés par le microbe dans le corps méme des poules atteintes du choléra. Depuis, on a montré que beaucoup de microbes pathogeénes faisaient de ces produits toxiques. Le microbe de la fiévre typhoide, celui du choléra, celui du pus bleu, celui de la septicémie expérimentale aigiie, celui de la diphtérie, sont grands producteurs de poisons. Les cultures du bacille de la diphtérie notamment sont, au VOL. XLVI. N Dn ; ‘ ios 170 Dr. E. Roux. [May 23, bout d’un certain temps, si chargées du principe toxique, que privées de microbes, elles causent 4 des doses infiniment petites, la mort des animaux avec tous les signes que l’on observe aprés l’inoculation du microbe lui-méme. Rien ne manque au tableau de Ja maladie, pas méme les paralysies consécutives, si la dose injectée est trop faible pour amener une mort rapide. Dans les maladies infectieuses la mort survient donc par intoxication, le microbe est non seulement agent de la contagion, mais aussi préparateur de poisons. Lorsqu’on introduit peu 4 peu, dans le corps des animaux, de ces sub- stances chimiques préparées par un microbe pathogéne, celui de la septicémie aigiie, par exemple, de facon a ne pas produire un empoisonne- ment brusque, mais une sorte d’accoutumance, ils deviennent réfrac- taires non seulement a l’action de doses toxiques qui les auraient tués tout d’abord, mais aussi a celle du microbe lui-méme. L’immunité que nous ne savions donner jusqu’ici, qu’au prix de l’introduction d’un virus vivant dans le corps, peut donc étre conférée par l’introduction d’un corps chimique dans les tissus. Ces substances vaccinales sont justement celles que nous avons vu causer la mort dans la maladie infectieuse; a forte dose elles tuent, 4 doses ménagées elles donnent VYimmunité. Ces expériences de “ vaccination ” au moyen de matiéres solubles, sans microbes, ont déja réussi pour diverses maladies infec- tieuses, et il est permis de croire qu’elles seront étendues bientét 4 plus grand nombre encore.* LHlles nous font comprendre la possibilité de la préservation d’une maladie par une autre; il suffit pour qu'il en soit ainsi, que les microbes de ces deux maladies élaborent des sub- stances chimiques semblables. Un animal, qui a regu une dose suffisante de ces produits, est-il devenu réfractaire parce que ceux-ci restent présents dans les tissus et empéchent le développement du virus? On sait, en effet, que la crois- sance de certains microbes est arrétée, dans les cultures, par l’accnmu- lation des produits qu’ils y forment. Mais ilfautse garder de conclure ce qui se passe dans les étres vivants de ce qui se fait dans nos flacons. Retirons du corps d’un animal réfractaire au charbon, par exemple, un peu de son sang et ensemengons-le avec de la bactéridie charbon- neuse. La culture sera abondante et rapide. Il n’y a done pas dans le sang de ce mouton réfractaire de matiére capable d’empécher la vie de la bactéridie. Cette expérience est, il est vrai, tout-a-fait grossiére, car il y a, au point de vue chimique, une différence énorme entre le sang contenu dans les vaisseaux d’un animal vivant et ce * Je rappellerai ici les travaux de M. Salmon sur le choléra hog; de MM. Toussaint, Chauveau, Wooldridge, Chamberland et Roux sur le charbon; de M. Charrin sur la maladie pyocyanique; de MM. Chamberlartd et Roux sur la septicémie aigiie; de MM. Beumer, Brieger, Chantemesse et Widal sur la fiévre typhoide; de M. Roux sur le charbon symptomatique, qui ont établi la vaccination par les substances chimiques élaborées par les microbes. 1889. ] Les Inoculations Préventives. v1 méme sang retiré du corps et déposé dans un flacon. Si elle donnait un résultat, c'est que l’état réfractaire serait di 4 un changement chimique véritablement énorme dans la composition des tissus. Pour la faire d’une maniére plus délicate, injectons dans la chambre anté- rieure de |’cil du méme mouton réfractaire au charbon, un peu de bactéridie virulente. La culture se fait trés-bien dans Vhameur aqueuse, mais elle y reste localisée.* 11 n’y a donc, dans cette humeur aqueuse, qui fait cependant partie du corps de l’animal, et qui participe aux modifications chimiques qui ont pu survenir en lai, il n’y a donc pas de substance capable de s’opposer a la vie du bacillus anthracis. Outre la question chimique il existe la question physio- logique, ainsi que le prouve |’expérience suivante. Si on injecte du virus du charbon symptomatique dans la cuisse d’un lapin, animal naturellement réfractaire 4 cette maladie, ancune tumeur ne se deé- veloppera, ’immunité parait donc complete. Produisons maintenant par un choc, ou par Vinjection d’une substance caustique, une lésion des tissus et faisons en ce point Vinoculation du virus, une tumeur charbonneuse apparait bientdt, et quoique le lapin ne prenne pas d’ordinaire le charbon symptomatique, il peut arriver qu’il succombe. C’est que dans ce cas les tissus détruits ont formé comme un milieu inerte ou le microbe a pu commencer sa culture sans obstacle. L’im- munité des lapins contre le charbon symptomatique ne tient donc pas a ce que leur corps constitue un milieu impropre a la culture du virus, puisque celui-ci, grace 4 un artifice d’inoculation, a pu l’envahir. Par des procédés semblables on peut aussi vaincre l’immunité acquise. Que se passe-t-il done quand on injecte du virus actif dans les tissus d’un animal réfractaire? Que deviennent les microbes? M. Metchnikoff nous a appris qwils sont bientdt détruits et que les agents de cette destruction sont surtout les globules blancs qui englobent les microbes et les digérent. Dans le corps des animaux non réfractaires les cellules blanches n’englobent pas les microbes, ou si elles essayent de le faire ceux-ci se développent quand méme. Une explication satisfaisante de ’immunité doit tenir compte de tous ces faits et faire la part de laction des produits. chimiques et.de la résistance des cellules. Nous pensons qu’actuellement l’interpréta- tion la meilleure est celle qui considére limmunité comme l|’accoutu- mance des cellules aux poisons sécrétés par les microbes. Lorsqu’un virus commence a se développer dans le corps d’un animal capable de prendre la maladie, il forme son poison et quand les cellules bianches viennent entreprendre la lutte, leur activité est entravée par cette production toxique, le microbe poursuit sa culture et la maladie progresse. Dans le corps d’un animal devenu réfractaire par injection préalable .de substances solubles ou par inoculation antérieure de virus atténué, les cellules ont déja été * Expérience due 4 M. Metchnikoff. N 2 ee eee ee eee. SS LS. -- fe a, _ i i = ~~ ee ~ 34 > 172 ' Presents. | [May 23, accoutumées au poison microbien. Les doses faibles qu’elles tronvent au début de la culture du virus n’arrétent pas leur action, elles entrent en lutte et digérent le parasite. Mais si, comme dans l’ex- périence du charbon symptomatique sur le lapin, une circonstance empéche [intervention cellulaire, la culture microbienne se fera, et dans ce foyer local il y aura bientdt assez de toxique préparé, pour que, malgré leur accoutumance préalable ou leur résistance naturelle, les cellules qui l’environnent soient réduites 4 Vimpuissance. On com- prend, en effet, qu’il ne puisse y avoir d’accoutumance pour les doses massives. C’est donc dans le temps qui suit immédiatement l’inocula- tion que se passe la lutte décisive. On congoit alors l’importance du siége de l’inoculation et de la quantité de matiére virulente introduite. Lorsque nous connaitrens bien les substances toxiques que forment les microbes pathogénes, nous pourrons peut-étre leur trouver des contrepoisons qui paralyseront leur action au sein méme des tissus. Mais je m’apergois que, depuis un instant déja, j’ai quitté le domaine des faits pour entrer dans celui de lhypothése et qu’il est temps que je m’arréte. Cette fagon de comprendre l’immunité concilie, je crois, les travaux inultipliés dans ces derniéres années. I] est probable que le temps la modifiera, mais ce qu’il ne changera pas c’est la reconnaissance de de tous pour celui qui par ses études sur les virus atténués et les vaccinations préventives, a permis d’aborder avec succés ce probléme de Vimmunité resté jusqu’ici impénétrable. The Society adjourned over Ascension Day to Thursday, June 6th. Presents, May 23, 1889. Transactions. Gottingen :—Ko6nigl. Gesellschaft der Wissenschaften. Nach- richten. 1888. S8vo. Gottingen. The Society. Kew :—Royal Gardens. Bulletin of Miscellaneons Information. No. 29. 8vo. London 1889. The Director. London :—Anthropological Institute. Journal. Vol. XVIII. No. 4. 8vo. London 1889. The Institute. Institute of Chemistry of Great Basie and Ireland. Register. 1889. 8vo. London. The Institute. Odontological Society of Great Britain. Transactions. Vol. XXI. No. 6. 8vo. London 1889. The Society. Photographic Society of Great Britain. Journal and Transac- tions. Vol. XIII. No.7. 8vo. London 1889. The Society. Royal United Service Institution. Journal. Vol. XXXII. No. 147. 8vo. London 1889. The Institution. 1889.) Presents. - 173 Transactions (continued). Victoria Institute. Journal of the Transactions. Vol. XXII. No. 88. 8vo. London 1889. The Institute. Zoological Society. Report of the Council. 1888. 8vo. London 1889. The Society. St. Petersburg:—Académie Impériale des Sciences. Bulletin. Nouvelle Série. No.1. 8vo. St.-Pétersbourg 1889. The Academy. Stockholm :—Kongl. Vetenskaps-Akademie. Ofversigt. 1889. No. 2. 8vo. Stockholm. The Academy. Vienna :—K.K. Geologische Reichsanstalt. Verhandlungen. 1889. Nos. 4-6. 8vo. Wien. The Institute. Observations and Reports. Berlin :—Commission fiir die Beobachtung des Venus-Durchgangs. Die. Venus-Durchgiinge 1874 und 1882. Bericht tiber die Deutschen Beobachtungen. Bd. II. 4to. Berlin 1889. — The Commission. Buenos Ayres:—Censo General de la Ciudad de Buenos Aires. 1887. TomolI. 8vo. Buenos Aires 1889. The Census Commission. Calcutta :—Meteorological Observations made at Seven Stations in India. October—December, 1888. Folio. [ Calcutta. ] The Meteorological Office, Calcutta. Cambridge, Mass. :—Harvard College Observatory. Annals. Vol. XVIII. Nos. 7-8. Vol. XX. Part 1. 4to. Cambridge [1888], 1889; Henry Draper Memorial. Third Annual Report of the Photographic Study of Stellar Spectra. 4to. Cambridge 1889. The Observatory. Liverpool:—Free Public Library, Museum, and Walker Art Gallery. Annual Report. 1889. 8vo. Liverpool. The Committee. London :—Local Government Board. Supplement in continuation of the Report of the Medical Officer for 1887. Folio. London 1889. The Medical Officer. Meteorological Office. Hourly Readings. 1886. Part 2. April to June. 4to. London 1889; Quarterly Weather Report. 1879. Part 4. October to December. 4to. London 1889; Report of the International Meteorological Committee, Ziirich, 1888. 8vo. London 1889. The Oitce: - Stationery Office:—Report of the Scientific Results of the Exploring Voyage of H.M.S. “Challenger.” Vol. XXX. Zoology. 2vols. Text and Plates. 4to. London 1889. The Stationery Office. 174 Presents. Observations, &e. (continued). Melbourne :—Observatory. Monthly Record. September to October, 1888. 8vo. Melbourne; Twenty-third Report of the Board of Visitors. Folio. Melbourne 1888. The Observatory Rome :—Osservatorio del Collegio Romano. Pontificia Universita Gregoriana. Vol. XXVII. Num. 11-12. 4to. Roma 1888. The Observatory. Washington :—Treasury Department, U.S. Government. Annual Report of the Comptroller of the Currency. 1888. 8vo. Washington. The Comptroller. Wellington :—Colonial Museum and Geological Survey of New Zealand. Meteorological Report, 1885, including Returns for 1883 and 1884, and Averages for previous years. 8vo. Wellington. : The Director. Williamstown, Mass.:—Hovkins Observatory, Williams College. Catalogue of North Polar Stars, Right Ascension for 1885.0. 4to. Williamstown 1888; The Development of Astronomy in the United States. A Discourse to commemorate the Fiftieth Anniversary of the Hopkins Observatory. By T. H. Safford. vo. Williamstown 1888. The Observatory. Or Election of Fellows. 187: June 6, 1889. The Annual Meeting for the Election of Fellows was held this day. Professor G. G. STOKES, LL.D., President, in the Chair. The Statutes relating to the election of Fellows having been read, Dr. Hugo Miller and Mr. Stainton were, with the consent of the Society, nominated Scrutators to assist the Secretaries in examining the lists. The votes of the Fellows present were then collected, and the fol- lowing candidates were declared duly elected into the Society :— Aitken, John. Hudson, Charles Thomas, LL.D. Ballard, Edward, M.D. Hughes, Professor Thomas Basset, Alfred Barnard, M.A. McKenny, M.A. Brown, Horace T., F.C.S. Poulton, Edward B., M.A. Clark, Latimer, C.E. Sollas, Professor William John- Cunningham, Professor David son, D.Sc. Douglas, M.B. Todd, Charles, M.A. Fletcher, Lazarus, M.A. Tomlinson, Herbert, B.A. Hemsley, William Botting, A.L.S. | Yeo, Professor Gerald F., M.D. Thanks were given to the Scrutators. ~ June 6, 1889. Professor G. G. STOKES, LL.D., President, in the Chair. Professor John Milne (elected 1887) and Mr. Henry Trimen (elected 1888) were admitted into the Society. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— VOL. XLYI, 0 176 Mr. T. Andrews. | [June 6, I. “ Electro-chemical Effects on Magnetising Iron. Part III.”* By THomas ANDREWS, F.R.SS.L. & E., M.Inst.C.E. Re- ceived May 3, 1889. Heperiments with Magnetic Polar Terminals. In course of an earlier part of this research I made many pre- liminary experiments to investigate the possible electro-chemical effect between the polished end disks or alternate polar terminals of straight round steel magnets when immersed as elements in some electrolytes, only the north and south terminal planes of each steel magnet being simultaneously exposed to the action of the electrolyte. Indications were afforded, under certain conditions, of a tendency on the part of the N. terminal of the magnet to become from some cause electro-positive to the 8. terminal plane. The apparatus, fig. 6, was used in the first series of observations. Fie. 6. The magnets were placed parallel at some distance apart in an up- right position, the lower end of each magnet, exposed in the solution, * Parts I and II are printed at yol. 42, p. 459, and vol. 44, p. 152. 1589.] _ Electro-chemical Effects on Magnetising Iron. 177 was covered with black india-rubber tubing, so that the flat polished terminal disks only were exposed to the action of the electrolyte. The bars used for the magnets were of polished steel, 4¢ inches long, ==; inch diameter, cut adjacently, previous to magnetisation, from a longer bar. A pair of magnets were securely placed in the wooden frame W, and the N.and S. terminals of each bar immersed in the solution placed below. A number of experiments were made with the arrangement, fig. 6, and with a galvanometer in circuit, using a pair of new steel magnets each time. In these observations the current appeared to flow from the N. to the 8. polar terminal ; care was exercised to ensure that the magnets were as near as practicable equally magnetised. The results of these preliminary observations are recorded in Table H. 7 ee ’ rr, 178 . Mr, T. Andrews. [June 6, Table H. Electro-chemical effect between north and south polar terminals of magnetised steel bars. E.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. ae Column 1. Column 2. Column 3. Column 4. commence- | ment of Nitric acid, Nitric acid, i experiment. sp. gr. 1-42, sp. gr. 1-42. Capa Cheacie and potassium | one-third, and eerie bende: bichromate potassium : (cone. solution) bichromate | in equal (conc. solution), volumes. two-thirds. seconds. 0 15 0:001 30 0-002 0-007 0-009 45 0 002 | minutes. | 1 0-002 0-010 0-005 0-009 | 2 0 006 0-011 0-004 0-009 I 3 0-006 O-:OLL 0-006 0°004 | 4 0-010 0-016 0-005 0-009 5 0:°014 0-029 0°006 0-011 6 0:016 0°045 0-008 0-011 7 0°023 0°051 0:009 O-O1L 8 0-038 0-050 0:009 0-011 9 0°054: 0°047 0°010 0-010 10 0-063 0-032 0-011 0-009 11 12 0:051 0-032 0-011 0 009 13 14 15 0°023 0-029 0-011 0009 16 | 17 0:009 ) 18 | 19 20 0-006 0°029 0-010 0 °027 21 22 23 24 25 0-006 0-040 0-013 0 :014 26 27 28 29 30 0:°009 0:031 0018 0:018 35 0°021 0 :025 0 :030 40 0°033 0-026 45 0041 AT 3. 0-132 50 0087 55 0:054 hour. 1 0-054 0°018 Ha a NT a et Se 1889. ] Electro-chemical Effects on Magnetising Lron. ES, Table H—continued. Electro-chemical effect between north and south polar terminals of magnetised steel bars. E.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. Time | from Column 5. Column 6. commence- ment of experiment. Nitric acid and ’ potassium Nitric acid, potassium bichromate solution, and bichromate ferric chloride solution. solution. : seconds. O — 0-009 0:030 —0:010 15 30 Ae —0 004: —0°030 0-018 45 minutes. e geri 1 0 :006 —0 004 0 ‘038 0:011 2 0-004: 0:009 0-009 3 —0°009 0:0083 0-000 0-038 4 — 0:009 0-004: 0-009 0 :023 5 0-000 0-004; 0-023 6 0-004: 0-003 0-009 0 °023 "6 0-006 0 -009 0 :027 8 0-009 0-006 0-004: 0:O11 9 0-009 0-009 0-004 0-000 10 0-010 0-004, 0-010 11 0:0138 0-004 0-010 0-009 12 0:014 0-006 0 :006 0-006 13 0-011 0-011 0-006 0-004 14 0 :027 0-011 0-004 0-004 15 0 054 0-014 0-006 0 -004 16 0:158 0-014 0-006 0,004. 17 0:271 0-018 0-009 0-004. 18 0-013 0-011 0-009 19 0-011 0-010 20 0-010 O -006 21 0 -004 0-006 0-002 22 0-004, 0-004: 23 0-009 0-004 24, 0-009 0-006 25 0:004 O 004, 0-004, 26 0 -004, 0-009 2inne 0°004 0-006 0 004 28 0-010 0-006 29 0-009 30 - 0:009 0-000 35 0-010 40 45 0 :014 AT 50 55 hour. 1 180 Mr. T. Andrews. [June 6, The preceding indications of the apparent tendency of the N. pole to become electro-positive in an electrolyte appeared somewhat singular,and after communicating these preliminary resultsto Professor G. G. Stokes, and conferring with him thereon, it was decided to make further experiments, and in course of these | have endeavoured to utilise some valuable experimental suggestions which Professor Stokes kindly made. Professor Stokes suggested that the results noticed in the first set of experiments with apparatus fig. 6 (see Table E) might probably be accounted for in the following manner, thus: supposing the bars to be equally magnetised permanently, then when the magnet bars were placed in the upright position the magnetism induced in the bars by the earth’s magnetic force would in one magnet strengthen, and in the other oppose the permanent magnetism, so that the stronger pole would be the N. one at the bottom. To investigate this possible aspect of the matter, the apparatus, fig. 7, was constructed with which to conduct the further investigations. The arrangement consisted of a wooden stand, W, the thick upper cross-bar of which was hollow and formed a tank sufficiently capacious to hold a suitable quantity of the electrolyte. The ends of two magnetised steel bars were securely inserted from below through the two holes in the bottom, so that the 1889. | Electro-chemical Effects on Magnetising Iron. 181 upper terminal disks only of the magnets were exposed to the solution. These holes were very accurately and carefully drilled, and when the bars were forced in, the arrangement was quite fluid-tight, and the greatest care was exercised to ensure that the terminal planes only of the magnets were exposed to the action of the solution. The steel rods were connected with a galvanometer which was introduced into the circuit, and the electrolyte was then poured into the upper receptacle and the readings of the galvanometer noted. A new wooden stand was prepared for each experiment, and a new pair of steel magnets was also employed for each observation. In many experi- ments the electrolyte was first introduced to the lower ends of the bars, and observations first taken of the relative electro-chemical positions of the N. and S. terminals at the lower end of the magnets. The solution was afterwards removed, the lower bar ends cleaned, and the electrolyte subsequently placed in the upper receptacle. By this means an indication of the relative electro-chemical position of both the upper and lower polar disks of the same pair of steel magnets was afforded. This series of experiments are recorded in Table F, Sets I to [V, and in Table H, sets V and VI. In other instances either the upper or lower polar terminals only of each pair of magnets were immersed in the electrolyte. The typical results of a considerable number of observations made in various ways in the above manner are recorded in Tables F, G, H, I, and J. Hezplanation of Results on Tables F, G, H, I, and J. The results on Table F, Sets I to IV, with cupric chloride as elec- trolyte, are the averages of numerous experiments on steel magnets which were tested in pairs with the electrolyte below, in apparatus fig. 7, the same pairs being afterwards tested at their opposite ter- minals with the electrolyte above. The results on Table G, Experiments Nos. 62, 57, 56, 55, 46, 43, 42, and 47, with cupric chloride as electrolyte, are typical experiments selected from a large number of observations too numerous to record in detail. In these experiments the electrolyte was placed in the position described on the table, either above or below only, with each pair of magnets under observation. The results on Table H, Sets V and VI, with cupric sulphate as electrolyte, are some typical observations selected from numerous experiments, in which the steel magnets were tested in pairs with the electrolyte below in apparatus fig. 7. The same pairs of magnets were subsequently tested at the opposite ends with the electrolyte above the magnets. The Experiments Nos. 71, 73, 75, and 79, on this ° table, with cupric bromide as electrolyte, were made with the solution below, experiments were also made with pairs of magnets placed in apparatus, fig. 7, and the results observed with the electrolyte above. 182 Mr. T. Audrews. Table F. Electro-chemical effect between north and south polar terminals of magnetised steel bars. E.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. Time from Cupric chloride solution. 4 commencement of experiment. Set I. Set IT. Average of 10 experiments. Average of 10 experiments. Electrolyte Electrolyte Electrolyte Electrolyte below. above. below. above. seconds. 9) 0°010 —0°018 —0°011 —0 007 30 0-004 0-011 0-001 0-001 minutes. . 1 0 007 0-000 | 0006 0-005 D 0°004 0 ‘004 0-008 0-007 } 3 0-010 0-004 0:014 0-012 . 4, 0-016 0-009 0:021 0-014 5 0-011 0-014 0-018 0-018 A 6 0°016 0-011 0-016 0-021 7 0°017 0-015 0-016 0 026 < 8 0-020 0-012 0-018 0-027 | 9 0:°021 0:014 0-013 0 -026 a 10 0:014 0-020 0-015 0-024: ; 11 0-025 0-014 0-017 0-022 12 0-021 0-025 0-016 0-021 5 13 0: 046 0-011 0-019 0-018 ‘@ 14 0-028 0-012 0-019 J) OROE 15 0°025 0°020 0-021 0-015 16 17, 0-032 0°011 0-021 0-015 18 19 20 0°024, 0°018 0 ‘023 0-015 21 22, 23 24: 25 0 025 26 27 28 29 30 0°025 35 0-026 40 0 036 45 0°022 1889.] Hlectro-chemical Effects on Magnetising Iron. 183 Table F—continued. Electro-chemical effect between north and south polar terminals of magnetised steel bars. EH.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. Time from Cupric chloride solution. commencement of experiment. Set IIT. Set IV. Average of 10 experiments. Average of 8 experiments. Electrolyte Electrolyte Electrolyte Electrolyte below. above. below. above. seconds. 0) —0-002 0-001 0-010 —0 022 30 0-006 0-009 0 003 0-005 minutes, 1 0-003 0-005 0-004 0-002 2 0-003 0-005 0-005 0-005 3 0-007 0-007 0-006 0-O1L 4, O-O1L 0-009 0-006 0-012 5 0-013 0-009 0-009 0-009 6 0-016 0-008 0-010 0-009 ” 0-018 0-007 0-008 0 007 8 0-016 0-008 0-010 0-012 9 0-016 0-008 0-012 0-008 10 0-016 0-010 0-011 0 007 11 0-015 0-008 0-012 0-002 12 0-013 0-008 0-012 0-008 13 0-015 0-010 0013 0-005 14. 0-016 0-015 0015 0-009 15 0-016 0-015 0-014 0-007 16 0-018 0-013 17 0:019 0-018 0-010 0-006 18 0-019 0-014 19 0-014 0-013 20 0-013 0-015 0-013 0-009 21 0-017 0-014 22 0-013 0-013 0 020 0-004: 23 0-014 0-012 24 0-013 0-012 25 0:011 0-012 0 °007 0-008 26 : 27 0-017 0-014: 28 29 30 0:013 0-011 0 ‘007 0-011 35 0-018 40 0:021 45 0:018 The pairs of magnets in the experiments of Set I varied in length from 8} inches, 6 inches, and 43 inches. In Sets II, IIT, and IV, the magnets of each pair were 6 inches long 184 Time from commencement of experiment. seconds. 0 30 minutes. Mr. T. Andrews. Table G. Electro-chemical effect between north and south polar terminals of magnetised steel bars. E.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. Cupric chloride solution. Experiment Experiment Experiment Experiment No. 62. No. 57. No. 56. No. 55. —w oe Electrolyte Electrolyte Electrolyte Electrolyte below. below. below. below. 0-006 0-006 0-009 0-004. 0-009 0-010 0-010 0-028 0-011 0-044 0-002 0-038 0-034 0-002 0-032 0-013 0-023 0-011 0-034 0-009 0-027 0-011 0-038 0-018 0-023 0-025 0-027 0-018 0-030 0-023 0-023 0-011 0-014 0-034 0-013 0-014 0-030 0-041. 0-018 0-027 0-023 0-027 0-018 0-048 0-023 0-027 0-044, 0 °054 [June 6, | Pe a ee ee ee ee Sagem 1889. ] Lilectro-chemical Effects on Magnetising Iron. 185 Table G—continued. Electro-chemical effect between north and south polar terminals of magnetised steel bars. EH.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. Time from ; : 2 ee ont Cupric chloride solution. of experiment. Experiment Experiment Experiment Experiment No. 46. No. 43. No. 42. No. 47. Electrolyte Electrolyte Electrolyte Electrolyte above. above. above. above. seconds. —0 027 —0:018 —0 009 —0 009 30 —0:004 0-000 0-000 minutes. 1 —0:003 0 :002 0 003 2 0-001 O 004 0-003 3 0 002 0-009 0 :006 A 0 004, 0:011 0:013 0-004 5 0-000 0:013 0 :014 0-003 6 0-014 0:018 0-005 He 0-014 0:018 0 :005 8 0-023 0-014, 0-006 9 0-023 0:011 0-006 10 0-023 0-011 0-004 11 0-014: 0-010 0-003 12 0-002 0-014 0-011 0-002 13 0-004 0:013 0-011 0-000 14 0 006 0:013 0011 0 002 15 0-006 0-011 0:011 0 :005 16 0-005 17 0-006 0-010 0:010 0 -006 18 0-005 19 0 004 20 0-005 0-011 0-010 0-003 21 0 -002 22 0-000 23 24, 25 0 002 0-010 0:014 27% 30 0-002 0-009 0:011 35 hours. 1 0-014 14 0-011 2 0-014 The magnets for the experiments in Table G were 6 inches long. 186 Mr. T. Andrews. [June 6, Table H. Electro-chemical effect between north and south polar terminals of magnetised steel bars. E.M.F.in volt. The electro-chemical posi- tion of the north polar terminal was positive, except where other- wise indicated. Time from ; commence- : ment of Cupric sulphate solution. f experiment. . Set V. Set VI. Electrolyte Electrolyte Electrolyte Electrolyte below. above. below. above. j seconds. j 0-009 —0:°014 —0-011 0-004 } 30 0-006 —0-006 —0-004 0-006 minutes. ; 1 0-006 0-000 —0-003 q 2 0-007 0 004 0-000 | 3 0-006 0-003 0-000 | 4 0-006 0 ‘002 0-002 5 0-007 0-003 0-004 6 0-009 0°009 0-006 7 0-010 0-009 0-010 8 0:010 0-006 0°016 9 0-010 0-004 0-020 *10 0:010 0-003 0-023 11 0°012 0-002 0-023 12 0:013 0-000 0-023 13 0-016 0025 14 0-020 0-000 0-028 15 0-041 0-000 0 °0380 16 0 054 0 :030 17 0-110 0 :027 18 0-122 0-018 19 0 054 0-016 20 0-023 0-016 21 0-011 0:014 22 0-009 0-000 0-027 23 0-000 0-009 0-041 24, 0-004 0-010 | 0:018 25 0004 0-010 26 0-011 27 0014 28 0:018 29 0-025 30 0-038 31 0 °054: 32 0-072 33 0-110 34, 0-203 35 0-226 hours. im 0 ‘006 1889.] Electro-chemical Effects on Magnetising Iron. 187 Table H—continued. Electro-chemical effect between north and south polar terminals of magnetised steel bars. E.M.F. in yolt. The electro-chemical position of the north polar terminal was positive, except where otherwise indicated. Time from |- eee Cupric bromide solution. ment of experiment. Experiment Experiment Experiment Experiment No. 71. No. 738. No. 75. No. 79. Electrolyte Electrolyte Electrolyte Electrolyte below. below. below. below. seconds. 0 0-009 0-006 —0-009 —0 004 30 0-004: 0-010 —0-004 0-006 minutes is 0-007 —0-001 0-006 2 0-006 0-003 0-007 3 0-000 0-011 0-004 0-006 4 0-002 0-014 0-002 0-006 5 0-005 0-014 0-004 0-009 6 0-007 0-020 0-003 0-009 7 0-009 0-024. 0-003 0-007 8 0-009 0-025 0-003 0-007 + 0-006 0 -027 0-004 0-006 10 0-007 0-025 0-005 0-005 11 0-007 0-028 0-003 0-004 12 0-009 0-028 0-009 0-003 13 0-009 0-032 0-010 0 -002 14 0-010 0-036 0-011 0-001 15 0-011 0-038 0-010 0-001 16 0-040 0-011 0 -002 17 0:014 0-040 0-009 0 -003 18 0-044: 0-009 0-003 19 0 -044. 0-006 0 -004 20 0-016 0-043 0-009 0 -004, 21 0-043 0-006 0 -005 22 0-020 0-043 0-004 0 -006 23 0-041 0-003 0 -005 24 0-041 0-006 0-003 25 0:019 0-041 0-005 0-004, 26 0 :041 0-005 0-003 27 0-040 0-002 0-003 28 0-040 0-004. 0-003 29 0 041 0-004 0-005 30 0:015 0-041 0-006 0-005 The magnets for the experiments in Table H were 6 inches long. Experiments were also made, using cupric bromide as an electrolyte, in which pairs of magnets 6 inches long were placed in apparatus, fig. 7, and the results observed when the electrolyte was thus above the magnets. The N. polar terminal was in the electro-positive position, with an E.M.F. somewhat similar in extent as when using cupric chloride. 188 ape Mr. T. Andrews. Table I. Klectro-chemical effect between north and south polar terminals | — of magnetised steel bars. E.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. Time from Cupric sulphate solution. commence- ment of experiment,| Experiment Experiment Experiment Experiment No. 81. No. 84. No. 85. No. 86. Electrolyte Electrolyte Electrolyte Electrolyte below. below. below. below. seconds. 0 004 —0-018 0-010 —0°014 30 0-002 —0-011 0-009 — 0-006 minutes. cl 0-004 0-002 0-009 0°002 2 0-004 0-001 0-009 0=008 3 0-005 0-002 0-010 0-004 4A 0 :005 0 002 0-011 0 005 5 0 -005 0 003 0-011 0-006 6 0-005 0-004 0-012 0-006 — 7 0 -006 0-005 0-011 0-006 8 0 -007 0-005 0-011 0-007 9 0-009 0-005 0-011 0-009 10 0-009 0 006 0-010 0-010 11 0 -007 0-006 0 -009 0-016 12 0-007 0 006 0-010 0-011 13 0 -006 0-006 0-010 0-011 14, 0 -004 0-007 0-011 0-012 15 0 -004: 0-009 0-011 0-012 16 0 -005 0-009 0-011 0-018 17 0 -005 0 -0U9 0-013 0-013 18 0 -006 0-009 - 0-014 0-014 19 0 -007 0-009 0-014 0-013 20 0 -006 0-008 0-014 0-013 21 0 -007 0-007 0-015 0-014 22 0 -006 0 -006 0-016 0-015 23 0 006 0 -005 0:017 0-016 24. 0 005 0-010 0:017 0-017 25 0-005 0-009 0-019 0-016 26 0-004 0-009 0 022 0°017 27 0-007 0 -009 0-024 » O7OLS 28 0-009 0-007 0-025 0-020 29 0-006 0-007 0-026 0-020 j 30 0-004 0 -007 0 ‘027 0-018 1889. | Electro-chemical Effects on Magnetising Iron. 189 Table I—continined. Hlectro-chemical effect between north and south polar terminals of magnetised steel bars. H.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. Time from Cupric sulphate solution. commence- ment of experiment. Experiment Experiment Experiment Experiment No. 87. No. 88. No. 90. No. 91. Electrolyte Electrolyte Electrolyte Electrolyte below. below. below. below. seconds. 0) —0-018 —0-011 —0°014, 0:018 30 —0°011 —0 ‘004, —0:°010 0°011 minutes. 1 0:001 0-001 0-002 0-010 2 0-003 0 002 0°003 0:011 3 0 003 0-005 0-004, 0-011 4, 0-006 0 :007 0-006 0:011 5 0 006 0-006 0-007 0:011 6 0-007 0-007 0-009 0-012 7 0-009 0 007 0-009 0°011 8 0 009 0-007 0-010 0-011 9 0-010 0-006 0:010 0°012 10 0-011 0G :006 0:°011 0:013 11 0-011 0 ‘007 0:011 0:013 12 0:013 0 °009 0°012 0 :014 13 0-014 0-009 0:013 0-014 14, 0-016 0-009 0:014 0°015 | 15 0-018 0:010 0:015 0-OL7 16 0-019 0-011 0-017 0:017 17 0-020 0:011 0:017 0 020 18 0-023 0-011 0:017 0-025 19 0 025 0-011 0-016 0-027 20 0-027 0:011 0:018 0 ‘080 a1 0 -027 0-011 0-019 0-033 22, 0 :027 0-011 0 :022 0-084: 23 0 -028 0:012 0-019 0°086 24, 0-030 0°012 0:019 0-038 25 0:031 0-011 0:019 0-040 26 0-031 0-011 0-020 0 °041 27 0:034 0:011 0-020 0042 28 0-035 0-010 0-020 0-044 29 0:036 0-011 0°019 0-044: 30 0-037 0-010 0:018 0 *044. The magnets for the experiments in the above Table I were in some experiments 83, and in others 44 inches long. Teak & pe eet OAL ” sae sh Oe aie ee 190 Mr. T. Andrews. | jane 6, q Table J. Electro-chemical effect between north and south polar terminals of magnetised steel bars. E.M.F. in volt. The electro- chemical position of the north polar terminal was positive, except where otherwise indicated. A concentrated solution of potassium bichromate containing ne Ee nitric acid. commencement of experiment. Experiment Experiment Experiment Experiment No. 92. No. 94. No. 95. No. 96. Electrolyte Electrolyte Electrolyte Electrolyte below. below. below. below. | seconds. 6) 0-023 0-000 —0 009 —0 ‘002 30 0'O11 0-004 —0 004 0-004 minutes. 1 0°006 0-009 — 0-002 0 -003 2 0-009 0-004 0 :000 3 0°009 0-004 0-006 - 0-003 4, 0°O11 0°010 0-011 0-006 5 0:011 0-009 0 -009 0-009 6 0-009 0-009 0-010 0-011 Ff 0:006 0-006 0-011 0-009 8 0-009 0-004 0-018 0-002 9 0:004 0-010 0-014 10 0-004: 0-006 O-OLias 0-004. ot 0-009 0-014 0 -009 12 0-010 0-011 0-004 12 O-oll 0-014 0-011 14, 0-009 0-013 0-004 15 0 :009 0-010 0 014, 0 -006 16 0-018 0-016 0-009 17 0-006 O-O11 0-018 0-006 18 0-014: 0 023 0-004 19 0-014 0-018 0-006 20 0-004 O-O11 0 °023 0 -006 21 0-014 Q -027 0-009 22 0-O11 0 023 0-000 23 0-018 0-018 0-018 24. 0-023 0-027 0-009 + 25 O-O11L 0-030 0-004 26 0-009 0-023 0:011 Dy 0-011 0-080 0:016 28 - 0-009 0 044: 0-020 29 0-009 0-038 0:°014 30 0 004. 0-034 0-011 35 0-009 1889. | Llectro-chemical Effects on Magnetising Iron. 1m Time from commencement of experiment. seconds. 0) 30 minutes. Table J—continued. Electro-chemical etfect between north and south polar terminals of magnetised steel bars. E.M.F. in volt. The electro-chemical position of the north polar terminal was positive, except where otherwise indicated. Nitric acid, potassium biehromate solution, Sulphate of iron (cone. solution) and ferrie chloride and caanae RABE aee PEC EELERE CEE 6 eee se Poy tt tt ae i a a ZASS=—= ol Ee EF ee Wal aD re ae be udp eg Vi Os P00S 400" 500: 600 * +700 800 : eo aie ~ Pounds . aatnat Several mechanical mixtures such as putty (chalk and oil), damp clay, and sand and water exhibit similar properties. If a lump of putty be well rolled or beaten it will be found to be slightly elastic, : but beyond the elastic limit to be easily stretched for a certain distance iy" and then to become almost hard, at the same time the appearance of the surface changes from a smooth, oily character to a dull granular one. The explanation in this case is that the hard particles of the mix- ture are, in its undisturbed state, separated each from its neighbours by a wall of fluid of finite thickness. When the material is distorted 1889. ] Properties of Vuleanised India-rubber. 237 the particles separate from one another in one direction and approach one another in a direction at right angles to this. As long as this approach merely involves the flow of the intervening fluid, the dis- tortion takes place with comparative ease; but when the approach of the particles brings them into actual contact with one another, the conditions change. There is no longer a store of fluid between, say, the vertical layers of particles which can be drawn on to supply the increased distance between the horizontal layers, and if the strain is augmented it must imply either a distortion of the hard particles themselves or an increase of volume of the whole mass. The latter is what happens in the cases just mentioned, the dull surface being the result of the fluid being sucked or rather pushed inwards by atmospheric pressure to supply the extra volume required in the interior, thus leaving the surface comparatively dry. The dry patch which is seen for a short time to surround fresh footsteps on some kinds of wet sand, is an example of the same kind of action. I will now describe the various experiments by which the results given in the table were obtained. (1.) Statical Measure of Young’s Modulus. The apparatus used is shown in fig. 1. The specimen of india- rubber is attached at one end to the balance beam and at the other to Fie. 1. Bf pi Mie il We er ey ee oe 2 238 Mr. A. Maliock. The Physical [June 6, _ a cord passing over a pulley, by means of which it can be subjected to any desired strain. Two very fine pins P, P’ (fig. 2), were fixed in the india-rubber at a distance of 10 inches from one another, and a thin strip of ebonite, H, | [ i | NF 7)! hae Z a sy I \ a CCRC t ESS e bs x y y having near one enda hole the size of the pin, and a mark, M,'10 inches from the hole, was then placed against the india-rubber with the pin P’ passing through the hole; thus, when unstrained, the pin P was exactly on the same level as M; when the india-rubber was strained the extension PM was measured by the cathetometer T— ~ ris 9 99 ” ? Young’s modulus. Let w = stretching force, 1 = unstrained distance between P and P’, l' = distance between P and P’ under the action of w, s = sectional area when length is J, HQ & 1889. | Properties of Vulcanised India-rubber. 239 V—] and since india-rubber is nearly incompressible, ls = 1's’, lw hence q= Ds To show the sort of agreement among themselves of the measures made in this way, I subjoin a table showing the results of five experiments, chosen at random from many others, on each of the kinds of india-rubber used, the units being inches and pounds. Soft grey. Red. - Hard grey. €=10. s = 02690. ~=10. s = 0°2307. ; = 10. s = 0°2625. /—1 Y l’—1." q v— q 0°228 1249 0°163 HOt 44 0-038 497 0 0°385 125 °3 0°345 | 163°0_ . 0:078 491-2 0-530 129 °2 OVATIOg «|<, 166-9 0°115 502 °3 bs77 1239 1°480 | 166°5 || O0O-°156 495 °7 4°85 1140 3°390 | 164°:5 0 °360 463 °5 The lowest values for g are those given by experiments in which the stretching force acted for the longest time. There is evidence also, which appears more strongly in the results represented by Diagram III, that q diminishes with the extension until the stretched length is about 3/2 times the natural length. (2.) Young’s Modulus. Dynamical Measure. AP (fig. 3) is a pendulum. The strip of india-rubber DC was held rigidly at D, and attached at C to the arm AB bracketed out from the pendulum. The experiments were made by observing the period of the pendulum with the india-rubber attached, and noting the difference between this and the natural period of the pendulum. The india-rubber was, of course, initially strained a little, and the amplitude of the vibrations used was never great enough to make the strain vanish. Let Ty be the natural period of the pendulum, | X = length of equivalent simple pendulum, T, = period of pendulum with india-rubber attached,. VOL. XLVI. S 240 Mr. A. Mallock. The Physical [June 6, AB =’7, 1 = natural length of india-rubber, 1, = DC = length of do. when attached to pendulum, s = natural sectional area of do., W = weight of pendulum. Then q as before being Young’s modulus, —, Wee = i) =e 721) 7los : The following are examples of the measures thus made :— A= 652in. r =135in. 4 =112in. W=102]b. Ty = 2°58] sec. Soft grey. ) Red. Hard grey. & = 0°2690. s = 0°2307. Ss = 0°2625. Ty. | q,. q. ees L,. q. T;. 1°725 1-788 1°315 tb 7 (73) 11°35 |193°1]| 1°784 12°25 | 217°75 || 1°33 1°72 Aol 1°30 1889. ] Properties of Vulcanised India-rubber. 241 It will be noticed that the values of qg thus obtained are much _greater for the soft grey and red varieties than those obtained statically, and the chief part of this difference is due to their not having time to take the subpermanent set which they would acquire if the period was very long, but in part also it must be due to a thermo- dynamic cause. 8.) Simple Rigidity. Statical Measure. The arrangement shown in fig. 4 was used for both the statical and dynamical measures of the rigidity. Fie. 4. D The india-rubber was held at each end by clamps of sheet brass C, C’ shown in section in fig. 5. Through the lower part of C the rod P passes, which fixes its position rigidly. The upper clamp C’ is attached to the bar AB, this bar being suspended in a horizontal plane by two silk threads from the point D. A small plumb-bob is also hung from D to facilitate the centering of the upper clamp and the divided circle F. When the S.2 » 242 Mr. A. Mallock. The Physical [June 6, Fia. 5. adjustments are complete, the axis of the india-rubber is the con- tinuation of the line DE. In the statical measures two silk threads were attached to A, one carrying the plumb-bob K, and the other the small weight W. W was drawn to one. side as shown, care being taken that the horizontal projection of AH was at right angles to AB, and that Hl was horizontal. The distance HK was then measured with a scale, and the angle through which the moment due to the horizontal com- ponent of force acting along AH turned the bar AB was read on the divided circle F. The section of the specimens of india-rubber used in these experi- ments being approximately square, and the reaction against torsion of a square prism being 0°883 that of a circular cylinder of the same area,* it follows that, since the torsional rigidity of similar prisms varies as the fourth power of the linear dimensions of their section, therefore the circular cylinder which has the same torsional rigidity as a square prism whose side is a, has a radius equal to (a/7) %/0°883. In fig. 4 let AB = 2Rh, ee CC' = 1 = length of the india-rubber, ELK AK =» b] = angle through which the india-rubber is turned, expressed in circular measure, s = sectional area of india-rubber, W = weight hung from H. r= - Then if coefficient of rigidity and = (s*/7)(0°883)?, 1 = 2RWee ~ w@r*r * * See Thomson and Tait, ‘Nat. Phil.,’ vol. 1, Part II, p. 257. New Edition. 1889. | Properties of Vulcanised India-rubber. 243 The measures of » from each specimen are given below. Many _ experiments were made, all agreeing very closely. gig 26 inn) tb = 11-2. “NX == 10°75. W = 100 grams. Soft grey. Red. Hard grey. r = 0°1560 in. r = 071607 in. gy = 01547 in. 2°25 | 0°785 | 65°68 || 2°3 | 0°915 | 50°76 || 4°20 | 0°612 | 161 °4 2°3 | 0°80 | 65°51 || 3°16 | 1°268 | 50°33 || 5°05 | 0°73 =| 162°4 | <<< x. Q. nN. x. Q. nN. x. a : | (4.) Rigidity, Dynamical Measure. The small weights hung from A being removed, the periods of the torsional oscillations of AB about DE were observed. Let T = the time of oscillation, w = weight of AB, g = acceleration of gravity in inches and seconds. Then for the other quantities involved, the notation being the same as In (3), _ 8rwR?7l = 30g’ For both the grey kinds of india-rubber the period varied consider- ably with the arc of vibration, owing partly to the extinction of the vibration being so rapid. The results were as follows :— Soft grey. Red. Hard grey. Are T n Are. T n Are T n 60 | 13:2 | 80°6 Goleta 60 | 9:4 156 30 12°7 ; 30 14:9 | 56°85 30 8°8 ' 10 12-0 8 10 14°8 10 8°55 ° 5 11°5 | 127°3 5 14.°9 5 8-4. 202 °6 What the explanation is of the very large values for n given by this method for the soft grey india-rubber, I have not been able to find out. 3 244 Mr. A. Mallock. The Physical [June 6, Both torsional measures give n greater for the soft grey than for the red, whereas by the measures of Young’s modulus, which should be very nearly equal to 3n, is considerably greater for the red. It is possible that there may be a kind of “‘ grain” in the sheets of the soft grey india-rubber, and that as the distortion produced by the extension in Experiments (1) and (2) is not in the same direction as that due to the torsion in Experiments (3), (4), the origin of the difference is to be looked for in this quarter. (5.) Young’s Modulus for Large Extensions. Diagram III gives the results of these experiments. They were made with the apparatus shown in fig. 1. The actual measures were made on strips of ($)? inch section, which were cut from the larger pieces in a planing machine by a sharp thin knife, wetted with dilute caustic soda. The sectional area of the strips so cut was exceedingly uniform, and its smallness was convenient, as it allowed of moderate forces being used to produce the required strains, which were increased until the breaking strain was reached. In the diagram the results are reduced to what they would have been had the piece of india-rubber operated upon been a cube of one inch when unstrained. The ordinates of the curves A, B, B’,C,C’, are the lengths which such cubes of soft grey, red, and hard grey india-rubber would respec- tively assume when stretched by forces represented by the abscisse. In the curves B, C, the readings were taken as rapidly as possible, while in B’, C’, an interval of two minutes was allowed between each successive addition to the strain. There were from thirty to fifty observations made for each curve. In the case of the soft grey, it did not seem to make much difference whether the readings were taken quickly or otherwise. Let # and J be the strained and natural lengths of the india-rubber, and y the stretching force, then g = ldy/s’dw, and if the material is incompressible, g = Udy/sdx. By this equation the curves H, F, G were deduced from Ay Bow to show the variation of g with the extension. It is worth white to observe that since if g remain constant for all extensions, —— , Fr ge 2 Be: qgA—F’ so that with qg constant, if a stretching force be applied equal per unit area to Young’s modulus, the extension will be infinite. | 1889.] Properties of Vulcanised India-rubber. 245 The breaking strains for the different specimens were found to be Mott crey........ 8100 pounds per square Re Gie aon is ol enaate ons sa | inch, nearly. Hard greyeu so as 44,00 The section is that at the moment of rupture. These numbers, therefore, are not the forces required to break a leneth of india-rubber of one square inch section when unstrained. To obtain the force requisite for this {purpose, the numbers given above must be divided by the extensions of the unit length at the moment of rupture. They are given directly by the termination of the curves A, B, C, and are about 820 lbs. for all three kinds. The tensile strength, however, is dependent in some measure on the time for which the force is applied, a long-continued application of force causing rupture when the force itself is not sufficient to pro- duce the maximum extension. This is particularly noticeable in the case of the hard grey india-rubber. (6.) Volume Hlastictty. There was some difficulty in obtaining a direct measure of this co- efficient, owing to the very large pressures which have to be employed to produce any measurable compression. The plan which succeeded best was to enclose the india-rubber in a Fia. 6. 246 Mr. A. Mallock, ‘he Physical -—-—« [June 6, glass tube, A A, fig. 6, the lower end of which was ground flat and cemented to a small plate of thick glass, B. The other end of the tube was drawn out to a neck, the aperture being about 0-1 inch in diameter. Wie After the india-rubber was enclosed’ and the plate B cemented on, A was filled with water, great care being taken that no air bubbles were enclosed. The neck was then closed by a ball of soft wax and turpentine mixture, D, and the whole immersed in water in a cast- iron cylinder (fig. 7), when it was subjected to a pressure of about 550 Ibs. per square inch. Under this pressure the water and india-rubber are somewhat com- pressed. Since the wax and turpentine is soft, the glass tube experiences but little difference of internal and external pressure, the mixture flowing in through the neck of the tube and forming a long filament, E, the volume of which represents the compression of the contents of the tube. When the pressure is gradually removed this filament is partly expelled, but retains its shape, and its length and sectional area being known, the data are supplied for computing the volume elasticity of the india-rubber. Let V' be the volume of the tube A, © Vv do. india-rubber, v do. the intruded wax, x’ the volume elasticity of water, Kk do. do. india-rubber, p _ the pressure in cylinder. 1889. | Properties of Vulcanised India-rubber. 247 Ve'p al = Fo—p(v'—V) As a test of the accuracy of the method, the volume elasticity of water was measured. The value found for «' was 296,000 lbs. per square inch, a result which is not far from the truth. The values for india-rubber were K Soft grey...... 198,000 REG ieee acts ee 115,000 Hard grey..... 940,000 These values are the means of all the experiments after the first. The first application of pressure, however, always produced a much more considerable compression, and if the volume of elasticity had been deduced from the first experiment only, its value would have been about half that given above in the case of the soft grey and red ; and for the hard grey, about one-eighth. (7.) Viscosity. The rate at which the vibration in Experiment (4) died away was used to determine the coefficient of viscosity. Diagram IV gives the “curves of extinction” for the three kinds of india-rubber. The ordinate of the curve is at each point, the ampli- Draqgram IV. Wi otal Ure 40 - 7 iad Pa ee Ll [2hs j Esl ea eho We 10 ‘ Complete “p% 248 Properties of Vuleanised India-rubber. [June 6, | tude which the vibration would have if the phase of the vibration was such that a maximum distance from the position of rest occurred at that point. Let X be the logarithmic decrement of the vibration, c, and c, the - amplitudes of the 1st and nth vibrations respectively, 1 c th ee : 1 * en ae log. 10 log an and if p be the coefficient of viscosity, _ 4Rewlr BTR 8qrr*T The symbols with the exception of \ having the same meaning as those in Experiment (4). The values found for p were Sott greyscale 13°74 Medi. g sigee ss ee 2°578 : pounds per square inch. Hard grey 7725 | The coefficient p represents the tangential force required to distort a cube of one inch of the material at the rate of one inch per second, independently of that necessary to overcome the elastic reaction, on the assumption that the viscous resistance to distortion varies as the rate of distortion. Part of the apparent viscosity however must be due to the difference of the rates at which the sub-permanent set is produced and removed. (8.) The densities of the specimens were Ned cies ctoyeyei sis 1°407 Hard grey .... 2°340 (9.) Chemical Composition. I had no means at my disposal here of making a good analysis, but a rough determination of the percentage of sulphur was obtained by decomposing a known weight of each kind with caustic soda and nitre, and observing the quantity of barium chloride required in each case to precipitate the sulphate formed. The results were Sulphur, per cent. SOLb oreyaus owls 57 Reds Wie einen 2°1 Hard orey is iia « 3°8 * Maxwell’s ‘ Electricity and Magnetism,’ vol. 2, 239. 1889.] Presents 249 Both the grey india-rubbers yield a considerable ash when burnt. _The hard grey, as is apparent from its density, containing a large percentage of inorganic matter. . The following table gives the mean of all the experiments. Table showing the Physical Properties of three kiads of Vulcanised India-rubber. Young’s modulus. Simple rigidity. Description of india-rubber. ree Statical. |Dynamical.| Statical. | Dynamical. BOUPeteyi, «esd... |° 1 * 289 124 195 65 80 to 127 COM ue slerowe , 198,000 13°74: 8) 8100 820 Sed Mee ves = <\iie'-1s, |. Lo, 000 2°578 7°3 6400 820 Hard grey........| 940,000 7 °725 4, *4, 4400 820 The units employed throughout this paper are the inch, pound, and second. The Society adjourned over the Whitsuntide Recess to Thursday, June 20th. Presents, June 6, 1889. Transactions. Baltimore:—Johns Hopkins University. Studies in Historical and Political Science. Ser. 7. Nos. 5-6. 8vo. Baltimore 1889. The University. Batavia :—Bataviaasch Genootschap van Kunsten en Weten- schappen. Notulen. Deel XXVI. Aflev. 3. 8vo. Batavia 1888; Tijdschrift voor Indische Taal-, Land- en Volkenkunde. Deel XXXII. Affev. 5. 8vo. Batavia 1889; Nederlandsch- Indisch Plakaatboek, 1602-1811. Deel V. 8vo. Batavia 1888. The Society. 250 Presents. ! mee : Transactions (continued). Brisbane :—Royal Geographical Society of Australasia (Queens- Jand Branch). Proceedings and Transactions. Vol. III. Part 2. 8vo. Brisbane 1889. The Society. Helsingfors :—Sallskapet for Finlands Geografi. Fennia. Vol. I. 8vo. Helsingfors 1889. The Society. Jena :—Medizinisch-Naturwissenschaftliche Gesellschaft. Jenaische Zeitschrift fir Naturwissenschaft. Bd. XXIII. Heft 2-3. Svo. Jena 1889. The Society. Liverpool :—Astronomical Society. Journal. Vol. VII. No. 6. 8vo. Liverpool 1889. The Society. London :—Geological Society. Quarterly Journal. Vol. XLV. No. 178. 8vo. London 1889. The Society. London Mathematical Society. Proceedings. Vol. XX. Nos. 346-348. 8vo. London 1888. The Society. Madrid :—Real Academia de Ciencias Exactas Fisicas y Naturales. Anuario. 1889. 12mo. Madrid. The Academy. New York :—Linnean Society. Abstract of the Proceedings for 1888-89. 8vo. |New York. | The Society. Palermo :—Circolo Matematico. Rendiconti. 1889. Fasc. 2. 8vo. Palermo. The Circolo. Paris :—Comité International Permanent pour l’Exécution Photo- graphique de la Carte du Ciel. Bulletin. Fasc. 3. 4to. Paris 1889. The Académie des Sciences. Société d’Encouragement pour l’Industrie Nationale. Annuaire. 1889. 8vo. Paris. The Society. Société Mathématique de France. Bulletin. Tome XVII. No.1. Svo. Paris 1889. The Society. Siena :—R. Accademia dei Fisiocritici. Atti. Ser. 4. Vol. I. Fasc. 1-2. 8vo. Siena 1889. The Academy. Stockholm :—Kongl. Vetenskaps-Akademie. Ofversigt. Arg. 46. No. 3. 8vo. Stockholm 1889. , The Academy. Tokio :—College of Science, Imperial University. Journal. Vol. II. Part 5. 4to. Tokyo 1889. The College. Trieste :—Societa Adriatica di Scienze Naturali. Bollettino. Vol. XI. 8vo. Trieste 1889. The Society. Turin:—R. Accademia delle Scienze. Atti. Vol. XXIV. Disp. 8-10. 8vo. Torino 1888-89. The Academy. Utrecht :—Physiologisch Laboratorium der Utrechtsche Hooge- school. Onderzoekingen. Derde Reeks. Vol. XI. 8vo. Utrecht 1889. : The School. Observations and Reports. Columbus :—Ohio Meteorological Bureau. Report for March, 1889. 8vo0. Columbus. The Bureau. 1889.] Presents. 251 Observations, &c. (continued). Dorpat :—Sternwarte. Meteorologische Beobachtungen. 1888. November — December. 8vo. [Dorpat|; Bericht tiber die Hrgebnisse der Beobachtungen an den Regenstationen der Kaiserlichen Livlandischen Gemeinniitzigen und Okonomischen Societat fiir das Jahr 1887. 4to. Dorpat 1889. The Observatory. Germany :—Konigl. Preussisches Geodatisches Institut. Polhéhen- bestimmungen aus dem Jahre 1886. 4to. Berlin 1889; Gewichtsbestimmungen ftir Seitenverhiltnisse in schematischen Dreiecksnetzen. 4to. Berlin 1889. The Institute. Glasgow :—Mitchell Library. Report. 1888. 8vo. Glasgow 1889. | The Library. _ London:—Admiralty Office. Hydrographic Department. Reports - of the Results of an Hxamination by the Officers of H.M.S. “Rambler” of the Slopes and Zoological Condition of Tizard and Macclesfield Banks. 1888. Folio. London 1889; Report on the Bore of the Tsien-Tang Kiang. 8vo. London 1888. The Department. Middlesex Hospital. Reports of the Medical, Surgical, and Pathological Registrars for 1887. 8vo. London 1888. The Hospital. Stationery Office. Report on the Scientific Results of the Voyage of H.M.S. “Challenger.” Vol. XXXI. Zoology. Ato. London 1889. The Office. University. Calendar for 1889-90. 8vo. London 1889. The University. Lyme Regis:—Rousdon Observatory, Devon. Meteorological Ob- servations. 1886, 1888. 4to. London 1887, 1889. Mr. Cuthbert H. Peek. Milan :—Reale Osservatorio di Brera. Pubblicazioni. Num. 34. 4dto. Milano 1889. The Observatory. Portugal:—Commissao dos Trabalhos Geologicos. Flora Fossil de Portugal. Monographia do Genero Dicranophyllum (Systema Carbonico). 4to.. Lisboa 1888. |The Commission. Turin :—Osservatorio della Regia Universita. Bollettino. Anno 1887. Obl. 8vo. Torino 1889. _ The Observatory. Washington :—Bureau of Navigation. Pilot Chart of the North Atlantic Ocean, May, 1889. [Sheet.] Washington. The Bureau. U.S. Signal Office. Bibliography of Meteorology. Part I. Temperature. [Lithogr.|] 4to. Washington 1889. The Office. 252 Presents. se Tamer, Buckman (S. 8.) and J. F. Walker. On the Spinose Rhynchonelle (Genus Acanthothyris, WV’ eee found in England. [ Excerpt. | Svo. York 1889. The Authors. Calendar of Wills proved and stifled in the Court of Husting, London, a.p. 1258-—a.p. 1688. Hdited, with Introduction, by Reginald R. Sharpe, D.C.L. Part I. 8vo. London 1889. _ The Corporation of the City of London. Delaurier (E.) Nouvelle Théorie de ?Univers. Folio. Paris [1889] - Théories Nouvelles des Causes des Maladies et des Fermentations. Folio. Paris [1889 ]. The Author. Downing (A. M. W.) The Eclipses of Jupiter’s Satellites. 8vo. London 1889. The Author. Fonblanque (H. Barrington de). Annals of the House of Percy. Two Vols. 8vo. London 1887. The Duke of Northumberland, K.G. Galloway (W.) Sinking Appliances at Llanbradach. 8vo. London [1889]. - he Author. Harley (G.), F.R.S. What is a Geyser? 8vo. Hdinburgh [1889]. The Author. Inglis-Parsons (J.) The Arrest of Growth in four cases of Cancer by a powerful Interrupted Voltaic Current ; a case of Pelvic Tumour treated by Galvano-Puncture: Cured. 8vo. London 1889. [ Excerpt. | 7 - The Author. Jones (T. R.), F.R.S. Notes on the Paleozoic Bivalved Entomostraca. No. 27. 8vo. [London] 1889. The Author, Jones (T. R.), F.R.S., and C. D. Sherborn. A Supplemental Mono- graph of the Tertiary Entomostraca of England. 4to. London 1889. The Authors. Loomis (E.) Contributions to Meteorology (Chapter 3). Revised edition. 4to. New Haven 1889. The Author. Major (F.) Spacial and Atomic Energy. PartI. 8vo. London 1889. The Author. O’Driscoll (F.) Notes on the Treatment of Gold Ores. 8vo. London 1889. The Author. Paganelli (A.) Risposta alle Osservazioni ed Appunti della Civilta Cattolica sulla Cronologia Rivendicata. S8vo. Prato 1889. The Author. Peschka (G. A. V.) Freie Perspektive. Bd. 1-2. 8vo. Leipzig 1888-89. The Author. Prince (C. Leeson) The Summary of a Meteorological Journal, 1888. Folio. [ Crowborough | 1889. The Author, Rambaut (A. A.) A New Determination of the Latitude of Dunsink Observatory. 4to. Dublin 1889. With two other Excerpts in 8yo. The Author. Schweerer (E.) Le Milieu Interstellaire et la Physique Moderne. 8vo. Paris 1889. The Author. 1889.] 7 On the Cavendish Experiment. 253 Steenstrup (J.), For. Mem. R.S. Mammuthjeger-Stationen ved Predmost. 8vo. Kjébenhavn 1889. With two other Excerpts in Svo. The Author. Tejera (M.) Origen y Constitucién Mecanica del Mundo. 8vo. Barcelona 1889. The Author. Volante (A.) Eureka Areostatica ai pie’ della Ferrea Corona. 4to. Torino 1888. The Author. Walker (J. F.) Communications [extracted] from the Yorkshire Philosophical Socicty’s Report, 1888. 8vo. The Author. June 20, 1889. Professor Sir G. GABRIEL STOKHS, Bart., President, in the Chair. Mr. John Aitken, Dr. E. Ballard, Mr. A. B. Basset, Mr. Horace T. Brown, Mr. Latimer Clark, Mr. Lazarus Fletcher, Mr. W. B. Hemsley, Dr. C. T. Hudson, Mr. E., B. Poulton, Professor W. J. Sollas, Mr. Herbert Tomlinson, and . Professor G. F. Yeo were admitted into the Society. The Presents received were laid on the table, and thanks ordered for them. The President announced to the Meeting that it had that after- noon been resolved by himself and the Council to address a letter to the Lord Mayor of London, expressing sympathy with his attempt to obtain some public recognition in this country of services rendered by M. Pasteur to science and humanity, and that the officers, with Sir James Paget, Sir Joseph Lister, Sir Henry Roscoe, and Professor Lankester, had been appointed to represent the Society at the meeting which the Lord Mayor had called for July Ist. The following Papers were read :— I. “ On the Cavendish Experiment.” By C. V. Boys, A.R.S.M., F.R.S., Assistant Professor of Physics at the Normal School of Science, South Kensington. Received May 29, 1889. The Cavendish experiment for determining the constant of gravita- tion, from which the density of the earth may be calculated, is so well known that there is no occasion to describe it. This experiment, TOL. XLVI 2 S| 254 Prof. C. V. Boys. — [ June 20, devised by the Rev. John Mitchell, F.R.S., was first carried out by Cavendish,* and has been since performed by Reich,+ Baily, and Cornu and Baille,$ who have all followed very closely the arrangement of Cavendish. | Owing to the very small value of the constant of gravitation, all these experimentalists have aimed at increasing the sensibility as much as possible. With this object, a long bee carrying at its ends considerable masses has been suspended by a very long and very fine wire. The attracting masses have been made as large as possible, and they have been brought almost into contact with the sides of the long box in which the beam is suspended. Cornu, it is true, has reduced the dimensions of all the parts to about one-quarter of the original amount. His beam, an aluminium tube, is only half a metre long, and it carries at its ends masses of + lb. each, instead of about 2 Ib. as used by Cavendish. This reduction of the dimensions to about one-quarter of those used previously is considered by Cornu to be one of the advantages of his apparatus, because, as he says, if the period of oscillation is unchanged, then the sensibility is independent of the mass of the suspended balls, and is inversely as the linear dimensions. i do not quite follow this, because, as I shall show, if all the dimensions are increased or diminished together the sensibility will be unchanged. If only the length of the beam is altered and the positions of the large attracting masses, so that they remain opposite to and the same distance from the ends of the beam, then the sensibility is inversely as the length. The other improvements introduced by Cornu are the use of mercury for the attracting masses which can be drawn from one pair of vessels to the other without coming near the apparatus, the use of a metal case connected with the earth to prevent electrical disturb- ances, and the electrical registration of the movements of the index on the scale which was placed 560 cm. from the mirror. The period of oscillation which has been used has varied between 398 seconds (Cornu) and 840 seconds (Cavendish). Cavendish found that with the very inconvenient period of 1800 seconds the balls knocked against the side of the case. The difficulty that has been met with has been the perpetual shifting of the position of rest, due partly to the imperfect elasticity or eae of the torsion wires, and partly, as Cavendish proved experimentally, to the enormous effects of air currents set up by temperature differences in the box, which with large apparatus it is impossible to prevent. In every case the power of observing was in * < Phil. Trans.,’ 1798, p. 469. t+ ‘ Comptes Rendus,’ 1887, p. 697. £ ‘ Phil. Mag.,’ vol. 21, 1842, p. 111. § ‘ Comptes Rendus,’ yol. 76, p. 954; vol. 86, pp. 571, 699, 1001. 1889. | On the Cavendish Experiment. 255 excess of the constancy of the effect actually produced. The observa- tions of Cornu are the only ones which are comparable in accuracy with other physical measurements, and these, as far as the few figures given enable one to judge, show a very remarkable agreement between values obtained for the same thing from time to time. Soor after I had made and found the value of quartz fibres for producing a very small and constant torsion, I thought that it might be possible to apply them to the Cavendish apparatus with advantage. Professor Tyndall, in a letter to a neighbour written some months ago, expressed the conviction that it would be possible to make a much smaller apparatus in which the torsion should be produced by a qnartz fibre. Last summer I began to prepare an instrument with a working beam five millimetres long, but other experimental work obliged me to put this on one side for a time. I have lately examined the theory of this instrument in some detail, and as I find that in many particulars there is an advantage in departing from the arrangement that has always been employed, I have lately prepared two pieces: of apparatus, which on trial fully bear ont the results of this inquiry. I shall, therefore, first give a short account of the principles that should be followed in the design of the Cavendish apparatus, and then describe the results which I have obtained up to the present time. As I have already stated, the sensibility of the apparatus is, if the period of oscillation is always the same, independent of the linear dimensions of the apparatus. Thus, if there are two instruments in which all the dimensions of one are times the corresponding dimensions of the other, then the moment of inertia of the beam and its appendages will be as n>: 1, and, therefore, the torsion also must be as n®:1. The attracting masses, both fixed and movable, will be as n?: 1, and their distance apart asn:1. Therefore, the attraction will be as n§/n? or n*:1, and this is acting on an arm x times as long in the large instrument as in the small, therefore the moment will be as n°:1, that is, in the same proportion as the torsion, and so the angle of deflection is unchanged. If, however, the length of the beam only is changed, and the attracting masses are moved until they are opposite to and a fixed distance from the ends of the beam, then the moment of inertia will be altered in the ratio n*:1, while the corresponding moment will only change in the ratio of n: 1, and thus there is an advantage in reducing the length of the beam until one of two things happens, either it is difficult to find a sufficiently fine torsion thread that will safely carry the beam and produce the required period, and this, I believe, has up to the present time prevented the use of a beam less than half a metre in length, or else when the length becomes nearly equal to the diameter of the attracting balls, they then act with such an VOL, XLVI. : U 256 Prof. C. V. Boys. [June 20, increasing effect on the opposite suspended balls, so as to tend to deflect the beam in the opposite direction, that the balance of effect begins to fall short of that which would be due to the reduced dimensions if the opposite ball did not interfere. Fig. 1 will make the meaning more clear. ab is the beam of the ordinary apparatus with a ball at Ree Fa each end. M is one of the attracting masses, and the other one occupies a symmetrical position on the opposite side of the centre O, but as the relations of each with the moving system are identical, it will be sufficient to consider only one. As the beam is supposed to become shorter, the small balls will occupy successively the places a’b’ and ab", while the large mass M will take the corresponding places shown by the dotted circles at M’ and M”. When it has reached the position M", at which the line joining its centre with O makes an angle of 45° with ab, the sensi- bility of the combination is still increasing, but not quite so fast as it would do if the attraction on the ball 6 did not partly counteract the attraction on the ball a. Should this position be chosen for the mass M, then the beam of the length ab” is not the best that can be used, if it is further shortened the sensibility will be still further increased, and will become a maximum when the beam has a length equal to half ab", that is, when the distance between the large balls is 2,/2 times the distance between the small ones. If the length of the beam is made successively equal to1,2,3..... 10 tenths of the distance a’b"", then the corresponding deflections will be represented by the numbers in the following table :— ab. Defiection. O-1 1-050 0-2 1-070 0:3 1:077 0-4, 1-082 0°5 1-088 0-6 1-080 0:7 1-066 0-8 1:037 0°9 0°982 1:0 0-911 1889.] On the Cavendish Experiment. 257 The unit deflection is that which would be produced if each large ball acted only on the small ball near it, and if the small balls occupied the positions ab". If the position which is chosen for each attracting mass is nearer the plane of the beam than the transverse plane, that is, if the azimuth of the large masses is less than 45°, the best length of the beam will be more than half that which would bring the ends opposite the attracting masses. It might be urged against this argument that a difficulty would arise in finding a torsion fibre that would give to a very short beam loaded with balls that it will safely carry a period as great as five or ten minutes, and until quartz fibres existed there would have been a difficulty in using a beam much less than a foot long, but it is now possible to hang a thing only half an inch long and weighing from 20 to 30 grains by a fibre not more than a foot in length, so as to have a period of five minutes. If the moment of inertia of the heaviest beam of a certain length that a fibre will safely carry is so small that the period is too rapid, then the defect can be remedied by reducing the weight, for then a finer fibre can be used, and since the torsion varies approximately as the square of the strength (not exactly because fine fibres carry heavier weights in proportion), the torsion will be reduced in a higher ratio, and so by making the suspended parts light enough, any slowness that may be required may be provided. Practically, it is not convenient to use fibres muclr less than one ten-thousandth of an inch in diameter, and these have a torsion ten thousand times less than that of ordinary spun glass. A fibre one five- thousandth of an inch in diameter will carry a little over 30 grains. Since with such small apparatus as I am now using it is easy to provide attracting masses which are very large in proportion to the length of the beam, while with large apparatus comparatively small masses must be made use of owing to the impossibility of: dealing with balls of lead of great size, it is clear that much greater deflec- tions can be produced with small than with large apparatus. For instance, to get the same effect in the same time from an instrument with a 6-foot beam that I get from one in which the beam is five- eighths of an inch long, and the attracting balls are 2 inches in diameter, it would be necessary to provide and deal with a pair of balls each 25 feet in diameter and weighing 730 tons instead of about 12 lb. apiece. There is the further advantage in small apparatus that 1f for any reason the greatest possible effect is desired, attracting balls of gold would not be entirely unattainable, while such small masses as two piles of sovereigns could be used where qualitative effects only were to be shown. Owing to its strongly magnetic qualities, platinum is unsuited for experiments of this kind. U 2 258 : Prof. C. V. Boys. [June 20, By far the greatest advantage that is met with in small appa- ratus is the perfect uniformity of temperature which is easily obtained ; whereas, with apparatus of large size, this alone makes really accurate work next to impossible. The construction to which this inquiry has led me, and which will be described later, is espe- cially suitable for maintaining a uniform temperature in that part of the instrument in which the beam and mirror are suspended. With such small beams as I am now using it is much more con- venient to replace the long thin box generally employed to protect the beam from disturbance by a vertical tube of circular section, in which the beam with its mirror can revolve freely. This has the further advantage that if the beam is hung centrally, the attraction of the tube produces no effect, and the troublesome and approximate calculations which have been necessary to find the effect of the box are no longer required. The attracting weights, which must be outside the tube, must be made to take alternately positions on the two sides of the beam, so as to deflect it first in one direction and then in the other. For this purpose they are most conveniently fastened to the inside of a larger metal tube which can be made to revolve on an axis coincident with the axis of the smallertube. There are obviously two planes, one containing and one at right angles to the beam, in which the centres of the attracting balls will lie when they produce no deflection. At some intermediate position the deflection will be a maximum. Now it is a matter of some importance to choose this maximum position for the attracting masses, because, in showing the experiment to an audience, the largest effect should be obtained that the instrument is capable of producing ; while in exact measures of the constant of gravitation this position has the further advantage that the only measurement which there is any difficulty in making, viz., the angle between the line joining the large masses and the line joining the small, which may be called the azimuth of the instrument, becomes of little consequence under these circumstances. In the ordinary arrangement the slightest uncertainty in this angle will produce a relatively large uncertainty in the result. I have already stated that if an angle of 45° is chosen, the distance between the centres of the large balls should be 22 times the length of the beam, and the converse of course is true. As it would not be possible at this distance to employ attracting balls with a diameter much more than one and a half times the length of the beam, and as balls much larger than this are just as easily made and used, it will be well to find out what will be the position for maximum deflection when the centres of the attracting balls are any distance apart. In the case already considered the problem gives rise to equations of too high an order to be readily solved, and so in the particular case referred to the result was obtained by arithmetical means. If the 1889. | On the Cavendish Experiment. 259 effect in the nearer ball only is considered, then it is easy to find the best position for any distance of the attracting mass from the axis of motion. Let P (fig. 2) be the centre of the attracting ball, N that of Fig. 2. the nearer attracted ball, O the axis of motion, c and a the distances of P and N from O, and w the distance from N of the foot of the per- pendicular from P on ON produced. Then the moment of N about O will be greatest when B24 2 pp Te 2 = 2(e&— a2), or what comes to the same thing when +a? ca cos? 0+ cos 9 = 3. The solutions of these equations are given in the following table :— e/a. hance x/ a. 1 0° O' 0 2 27 45 0-77 3 42 16 22 4 51 19 1:50 5 58 20 1°62 6 63 y 15 1:70 7 66 44 1:76 8 69 23 1°82 9 71 17 1°88 10 72 50 1°95 co 90 0 2°00 260 | Prof. C. V. Boys. [June 20, These figures are represented by the curve in fig. 3, which shows the best position for an attracting mass at any distance from the Fia. 3. axis O. The inclination of this with the line ON at the point N is 35° 16’, or an angle of which the tangent is equal to 1/./2. This curve also shows the best position from which a source of light at any distance from O would most brightly illuminate a small surface at N lying along ON. If now an attracting ball is placed in a position of maximum effect with its centre on this line it will act on the further suspended ball, tending to deflect the beam in the opposite direction, and this will become more marked as the distance between the centres of the attracting balls increases, and so the increased effect which would be due to a greater attracting ball may be largely compensated by the increased action on the remote end of the beam. The azimuth at which the maximum effect is produced is also changed. I have practically overcome this difficulty by arranging the two sides of the apparatus at different levels. Hach large ball is at or near the same level as the neighbouring small ball, but one pair is removed from the level of the other by about the diameter of the large balls which in the apparatus which I have now the honour to 1889. ] On the Cavendish Experiment. 261 submit to the Society is nearly five times as great as the distance in plan between the two small balls. In order to realise more fully the effect of a variety of arrange- ments, I have, for my own satisfaction, calculated the values of the deflecting forces in an instrument in which the distance between the centres of the attracting balls is five times the length of the beam, for every azimuth and for differences of levels of 0, 1, 2, 3, 4, and > times the length of the beam. This calculation is very much facilitated by the property of the circle illustrated in fig. 4. If the diameter is divided into any number of equal parts, and perpendiculars drawn to cut the circle, then the squares of lines drawn from any one of the points on the diameter to all the intersections (including the two ends of the diameter) are in arith- metrical progression, and the common difference is equal to twice Fig. 4. the number of parts included between that point and the centre. If the diameter is divided into ten parts, a and 6 are the positions of the ends of the beam, and the semicircle is the path of the centre of the large mass. When this is at any position P the resolved force at a is equal to PM/Pa?. Now all the quantities PM? and Pa? are small whole numbers, and the squares of the true distances of P from a when ais at different levels are small whole nnmbers also, so that all the logarithms can be found on the first four pages of Chambers’s tables. It is for this reason that it is most convenient to represent the result of the calculation on a diagram in which the abscisse are the projec- tions of the centre of the attracting mass on a plane passing through the centres of the small balls. In fig. 5 the dotted circle represents the possible positions of the centre of the attracting mass, and a, b the small balls. The heavy Curve 1 shows the value of the moment due to the ball a alone. The reversed Curve 2 in the same way shows the moment of the ball } in the opposite direction when that ball is at the same levelasa. The Curve 3 is the difference between these two, and from this actual resultant moments may be found. The maximum of this curve is in 262 Prof. C, V. Boys. [June 20, Hid, 5. AAT 6, Ba AE AE § sp | a slightly different position from that of the Curve 1, and its greatest value is only just over half that of the first curve, which shows that the sensibility can be nearly doubled by lowering the ball 6 until it is too far down to be appreciably attracted by the ball which is on a level with a. The five curves below 2 show the effect of lowering 6 until it is 1, 2,3, 4.and 5 times the length of ab below the general level, and the five curves between 1 and 3 in the same way represent the values of the balance in favour of a when 6 is at these different levels. The curves when drawn are instructive in that they show both the relative advantages of the various differences of levels, and from the curvature at the maximum positions the practical importance of correctly determining the azimuth. By reference to the number on the vertical scale it is also easy to directly compare the sensibility of the apparatus with any of the arrangements which have been in use. For instance, calling in every case the half length of the beam unity and the dimensions of the other parts by numbers in proportion, we have in the apparatus of Cavendish— Hquivalent distance between centres of large and small balls (8:95-mches) 2.92... (- alpen 0°249 Diameter of large balls (12 inches) ............ 0°333 Comparative value of deflecting force 0°3333/0°249? 0°596 1889. | On the Cavendish Experiment. 263 In my apparatus it is simply necessary to multiply the cube of the diameter of the large balls by the ordinate of the curve, to find on the same scale the value of the deflection. This requires that the large balls should be made of material of the same density in the two cases, and that the periods should be the same. Now the diameter of the large ball in the new apparatus is 64 times the length of the beam, and so the comparative value of the deflecting force is 0°0425 x 6:43 = 111, a figure which is 18-7 times as great as the figure found for the apparatus of Cavendish. If then the large balls have the same density as those used by Cavendish and the period of oscillation is the same, the angular deflection will be 18°7 times as great. Having now found that with apparatus no bigger than an ordinary galvanometer it should be possible to make an instrument far more sensitive than the large apparatus in use heretofore, it is necessary to show that in practice such a piece of apparatus will practically work, and that it is not hable to be disturbed by the causes which in large apparatus have been found to give so much trouble. I have made two instruments of which I shall only describe the second, as that is better than the first both in design and in its behaviour. The construction of this is made clear by fig. 6. To a brass base provided with levelling screws is fixed the vertical brass tube, ¢, which forms the chamber in which the small masses a, } are sus- pended by a quartz fibre from the pin at the upper end. ‘These little masses are cylinders of pure lead 11°3 mm. long and 3 mm. in diameter, and the vertical distance between their centres is 50°8 mm. They are held by light brass.arms to a very light taper tube of glass, so that their axes are 6°5 mm. from the axis of motion. The mirror m, which is 12°7 mm. in diameter, plane and of unusual accuracy, is fastened to the upper end of the glass tube by the smallest quantity of shellac varnish. Both the mirror and the plate-glass window which covers an opening in the tube were examined and afterwards fixed with the refracting edge of each horizontal, so that the slight but very evident want of parallelism between their faces should not interfere with the definition of the divisions of the scale. The large masses M, M are two cylinders of lead 50°8 mm. in diameter, and of the same length. They are fastened by screws to the inside of a brass tube, the outline of which is dotted in the figure, which rests on the turned shoulder of the base so that it may be twisted without shake through any angle. Stops (not shown in the figure) are screwed to the base, so that the actual angle turned through shall be that which produces the maximum deflection. A brass lid made in two halves covers in the outer tube and serves to maintain a very perfect uni- formity of temperature in the inner tube. Neither the masses M, M, nor the lid touch the inner tube. The period of oscillation is 80 seconds. 264 Prof. C. V. Boys. his Th; — | ii Tn | : ih il i i . - With this apparatus placed in an ordinary room with draughts of air of different temperatures and with a lamp and scale such as are used with a galvanometer, the effect of the attraction can easily be shown to a few, or, with a lime-light, to an audience. To obtain this 1889. ] On the Cavendish Experiment. 205 result with apparatus of the ordinary construction and usual size is next to impossible, on account chiefly of the great disturbing effect of air currents set up by difference of temperature in the case. The extreme portability of the new instrument is a further advantage, as is evident when the enormous weight and size of the poeancting; masses in the ordinary apparatus are considered. However, this result is only one of the objects of the inquiry which I have now the honour to submit to the Royal Society. The other object which I had in view was to find whether the small apparatus, besides being more sensitive than that hitherto employed, would also be more free from disturbances and so give more consistent results. With this object’ I have placed the apparatus in a long narrow vault under the private road between the Museum and the Science Schools. This is not a good place for experiments of this kind, for when a cab passes overhead the trembling is so great that loose things visibly move; however, it is the only place at my disposal that is in any degree suitable. A large drain pipe filled with gravel and cement and covered by a slab of stone forms a fairly good table. The scale is made by etching millimetre divisions on a strip of clear plate glass 80 cm. long. This is secured at the other end of the vault at a distance of 1053°8 cm. from the mirror of the instrument. A telescope 132 cm. long and with an object-glass 5:08 cm. in diameter rests on V’s clamped to the wall, with its object-glass 360 cm. from the mirror. Thus any disturbance that the observer might produce if nearer is avoided and at the same time the field of view comprises 100 divisions. While the observer is sitting at the telescope he can by pulling a string move an albo-carbon light mounted on a carriage so as to illuminate any part of the scale that may happen to be in the field of the telescope. The white and steady flame forms a brilliant background on which the divisions appear in black. Yhe accuracy of the mirror is such that the millimetre divisions are clearly defined, and the position of the cross- wire (a quartz fibre) can be read accurately to one-tenth of a division. This corresponds to a movement of the mirror of almost exactly one second of arc. The mode of observation is as follows: When all is quiet with the large masses In one extreme position, the position of rest is observed and a mark placed on the scale. The masses are moved to one side for a time and then replaced which sets up an oscillation. The reading of every elongation and the time of every transit of the mark are observed until the amplitude is reduced to three or four centi- metres. ‘T’he masses are then moved to the other extreme position and the elongations and transits observed again, and this is repeated as often as necessary. On the evening of Saturday, May 18th, six sets of readings were 266 Prof. C. V. Boys. [June 20, taken, but during the observations there was an almost continuous tramp of art students above, producing a perceptible tremor, besides which two vehicles passed, and coals were twice shovelled in the coal cellar, which is separated from the vault in which the observations ~ were made by only a four and a half inch brick wall. The result of all this was a nearly perpetual tremor, which produced a rapid oscilla- tion of the scale on the cross-wire, extending over a little more than lmm. This increased the difficulty of taking the readings, but to what extent it introduced error I shall not be able to tell until I can make observations in a proper place. In spite of these disturbances, the agreement between the deflec- tions deduced from the several sets of observations and between the ‘periods is far greater than I had hoped to obtain, even under the most favourable conditions. In order to show how well the instru- ment behaved, I have copied from my note-book the whole series of figures of one set, which sufficiently explain themselves. Correction oes Pies Teee hic ses True Time of for transit | True me = bas ment, | Position transit of of true half ; i ’ | of rest. 36 ‘09. position | period. of rest. Ba 1 36-18| 9 825-0] +0-08 38°15 eqs, 5° +0° Ss suerarn| ONE? ences 9 45°5| —o-1s | 802 47 +28 24°80 0807 36°21 ll 5°38 + 0°24 80 +0 27-98 20 -00 0-807 36 *20 | 12 25°8 —0°28 79 +9 43°40 16°12 0-803 36 °22 13 45°0 +0°41 80°1 30 +42 12°98 0-806 86°21 15%) 260 —0°47 80°1 ates 10946) peeqe a WRONee 16° 25:0 |: 0°63) 5 aa 32-50 8°38 0-808 36°24 17 46:0 —0-91 80°5 5a) a OTe eet oes 19° 45) Ses Hane Beha BAT nl ies asl 8G 22 20 27°0| 1°58 ae 38 -95 4°45 36°26 21 44°0 +1°94 0°8066 | 80 -08 It will be noticed that the true position of rest is slightly rising in value, and this rise was found to continue at the rate of 0°36 cm. an hour during the whole course of the experiment, and to be the same when the large masses were in the positive or negative position. The motion was perfectly uniform, and in no way interfered with the accuracy of the experiments. It was due, I believe, to the shellac fastening of the fibre, for I find that immediately after a fibre has been attached this movement is very noticeable, but after a few days it almost entirely ceases; it is, moreover, chiefly evident when the 1889. | On the Cavendish Experiment. 267 fibre is loaded very heavily. At the time that the experiment was made the instrument had only been set up a few hours. The mean decrement of three positive sets was 0°8011, and of three negative sets, 0'8035. The observed mean period of three positive sets was 79°98, and of three negative sets, 80°03 seconds, from both of which 0:20 must be deducted as the time correction for damping. The deflections obtained from the six sets of observations taken in eroups of three, so as to take into account the effect of the slow change of the position of rest, were as follows :— Hvom sets 12. and 3... . «..-.« 17°66 + 0:01 a asia ae ds pte 0 ha eee a 17°65 + 0:02 Pe OF AGEING, Doe o/s) secs ie 17°65 + 0°02 poeta ee vAT. O25; are ava ssc 17°65 + 0:02 An examination of these figures shows that the deflection is known with an accuracy of about one part in two thousand, while the period ‘is known to the four thousandth part of the whole. As a matter of fact the discrepancies are not more than may be due to an uncertainty in some of the observations of half a millimetre or less, a quantity which, under the circumstances, is hardly to be avoided. The result of these experiments is complete and satisfactory. Asa lecture experiment the attraction between small masses can be easily and certainly shown, even though the resolved force causing motion is, as in the present instance, no more than the one two hundred- thousandth of a dyne (less than one ten-millionth of the weight of a grain), and this is possible with the comparatively short half period of eighty seconds. Had it been necessary to make use of such half periods as three to fifteen minutes which have been employed hitherto, then, even though a considerable deflection were produced, this could hardly be considered a lecture experiment. The very remarkable agreement between successive deflections and periods shows that an absolute measure made with apparatus designed for the purpose, but on the lines laid down above, is likely to lead to results of far greater accuracy than any that have been obtained. For instance, in the original experiment of Cavendish there seems to have been an irregularity in the position of rest of one-tenth of the deflection obtained, while the period showed discrepancies of five to fifteen seconds in seven minutes. The experiments of Baily made in the most elaborate manner were more consistent, but Cornu was the first to obtain from the Cavendish apparatus results having a precision in any way comparable to that of other physical measurements. The three papers, published by him in the ‘ Comptes Rendus,’ of 1878, re- ferred to above, contain a very complete solution of some of the problems to which the investigation has givenrise. The agreement between the successive values, decrement, and period is much the same that I have 268 On the. Cavendish Experiment. [J une 20, obtained, nevertheless the means of the summer and of the winter observations differ by about 1 per cent. I have not referred to the various methods of determining the constant of gravitation in which a balance, whether with the usual horizontal beam, or with a vertical beam on the metronome principle, is employed. They are essentially the same as the Cavendish method, except that there is introduced the friction of the knife-edges and the unknown disturbances due to particles of dust at these points, and to buoyancy, without, in my opinion; any compensating advantage. However, it would appear that if the experiment is to be made with a balance, the considerations which I have advanced in this paper would point to the advantage of making the apparatus small, so that attracting masses of greater proportionate size may be employed, and the disturbance due to convection reduced. It is my intention, if I can obtain a proper place in which to make the observations, to prepare an apparatus specially suitable for abso- lute determinations. The scale will have to be increased, so that the dimensions may be determined to a ten-thousandth part at least. Both pairs of masses should, I think, be suspended by fibres or by wires, so ‘that the distance of their centres from the axis may be accurately measured, and so that in the case of the little masses the moment of inertia of the beam, mirror, &c., may be found by alter- nately measuring the period with and without the masses attached. The unbalanced attractions between the beam, &c., and the large masses, and between the little masses and anything unsymmetrical about the support of the large masses, will probably be more accu- rately determined experimentally by observing the deflections when the large and the small masses are in turn removed, than by calcula- tion. ’ If anything is to be gained by swinging the small masses in a good Sprengel vacuum, the difficulty will not be so great with apparatus made on the scale I have in view, 7.e., with a beam about 5 em. long, as it would with large apparatus. With a view to reduce the con- siderable decrement, I did try to maintain such a vacuum in the first instrument, in which a beam 1°2 cm. long was suspended by a fibre so fine as to give a complete period of five minutes, but though the pump would click violently for a day perhaps, leakage always took place before long, and so no satisfactory results were obtained. With an apparatus such as I have described, but arranged to have a complete period of six minutes, it will be possible to read the scale with an accuracy of one ten-thousandth of the deflection, and to determine the time of vibration with an accuracy about twice as great. 1889.] On Time-lag in the Magnetisation of Iron. 269 Il. “On Time-lag in the Magnetisation of Iron.” By J. A. Ewine, B.Sc., F.R.S., Professor of Engineering in Univer- sity College, Dundee. Received June 18, 1889. When any change is made to take place in the magnetic force acting on a piece of soft (annealed) iron, a considerable time elapses before the resulting change in the magnetism of the piece is complete. The sluggishness which soft iron exhibits in assuming its full mag- netism when a magnetic force is imposed upon it was referred to as follows in the account which I wrote, some years ago, of experiments on the magnetic qualities of iron :—* ‘“‘Some evidence was given that, in addition to much static hysteresis, there is a small amount of viscous lagging in the changes of magnetism which follow changes of magnetising force. I re- peatedly observed that when the magnetising current was applied to long wires of soft iron, either gradually or with more or less sudden- ness, there was a distinct creeping up of the magnetometer deflection after the current had attained a steady value, as measured by the de- flection of the galvanometer through which it passed. This action was sometimes so considerable as to oblige me to wait for some minutes before taking the magnetometer reading.”’ In his paper “On the Behaviour of Iron and Steel under the Opera- tion of Feeble Magnetic Forces,’+ Lord Rayleigh has remarked on the same phenomenon in soft iron. In his experiments the relation of the magnetic force to the resulting magnetisation of the specimen was studied by means of a magnetometer furnished with a ‘‘ compen- sating coil,” through which the magnetising current passed, and which was so placed that its action on the needle of the magnetometer balanced the action of the iron, giving no deflection. When very feeble magnetic forces were applied to hard iron or to steel, he found that a perfect balance might be obtained by adjusting the position of the compensating coil, and so established the fact that the suscepti- bility to small magnetic forces, or to small changes of force, is a defi- nite quantity, which is independent of the amount of the small change of force. He observes that with hard iron and steel the compensat- ing coil might be set so that neither at the moment of closing the circuit of the magnetising current nor afterwards was there any deflec- tion of the magnetometer, which means that (so far as the magneto- meter can decide) the metal assumes its magnetic state instanta- neously. He goes on to say that soft iron shows much more complicated effects: ‘When the coil was so placed as to reduce as much as possible the instantaneous effect, there ensued a drift of the * “ Hxp, Researches in Magnetism,” ‘ Phil. Trans.,’ 1885, p. 569, § 52. + ‘Phil. Mag.,’ March, 1887, p. 230. 270 Prot. J. Hwiness 23 [June 20, magnetometer needle . . . . in such a direction as to indicate a con- tinued increase of magnetisation. Precisely opposite effects followed the withdrawal of the magnetising force. The settling down of the iron into a new magnetic state is thus shown to be far from instanta- neous. On account of the complication caused by the free swings of — the needle, good observations on the drift could not be obtained with this apparatus, but it was evident that whilst most of the anomalous action was over in 3 or 4 seconds, the final magnetic state was not attained until after about 15 or 20 seconds.” Lord Rayleigh then cites my observation, quoted above. In the following experiments Lord Rayleigh’s method of the com- pensating coil has been made use of for the purpose of examining in some detail this “drift,” or “creeping,” or quasi-viscous change of magnetism which follows any change in the magnetic force acting on soft iron. The magnetometer was a light Thomson mirror directed by the horizontal component of the earth’s field, and having a free period of double swing amounting to nearly 14 seconds. The specimen of iron used in the greater number of the experiments was a straight piece of thick wire 0°404 cm. in diameter and 39°6 cm. long, over which was slipped a tube with a magnetising solenoid wound upon it. The wire was set in a vertical position, magnetically west of the magnetometer, with its top end on a level with the mirror, and generally 6 cm. distant from it. The compensating coil was wound on a wooden frame, which could be moved along a “‘ geometric slide” towards or from the magnetometer in the east-west line through the mirror, for the purpose of balancing the magnetic effect of the iron. In some of the experiments another compensating coil was used to balance the effect on the magnetometer of the magnetising solenoid, - but generally the simpler plan was followed of including the effect of the solenoid in the determination of the compensating coil’s action on the magnetometer. To prevent the vertical component of the earth’s field from acting on the iron, a second magnetising solenoid was wound over the first, and a constant current of the proper strength to neutralise the earth’s field was maintained in it without interruption. The main magnetising current was regulated by having in its circuit a box of resistance coils, and also the liquid slide described in my former paper.* This allowed the magnetic force to be changed either suddenly or gradually, and the slide also allowed the method of de- magnetising by numerous reversals of a continuously diminishing magnetic force to be resorted to whenever it was desired to reduce the iron to a magnetically neutral state. To soften the wire it was heated to redness by being slowly drawn * Loe. cit., § 18, p. 537. 1889. | On Time-lag in the Magnetisation of Tron. 271 through a Bunsen flame. After it was. put in place the method of reversals was applied to extract a small amount of magnetism which it had acquired in being handled. In the experiments which I shall first describe the effects of very feeble magnetic force were examined by making and breaking the circuit of the magnetising solenoid while the current was adjusted to produce a force of less than O'leg.s. It was found that the wmmedzate effect of each make and break could be balanced very exactly by adjusting the position of the compensating coil, and so long as the magnetising force was considerably less than 0-1 c.g.s. the distance at which the coil had to be set to give this balance was as nearly as possible independent of the value of the force, and. was the same for “ break” as for ‘‘ make.” The position of the coil was adjusted so that at the instant when the magnetising current was set up by pressing down a contact key, there was no sudden deflection of the magnetometer mirror to either side. When the compensation was right the spot of light simply began to drift slowly towards the side corresponding to increase of magnetism; when there was over- compensation, the spot of light gave a quiver to the opposite side before beginning to drift, and the position of the coil was adjusted by drawing it back little by little until the quiver on pressing down the key disappeared. The amount of magnetism that was balanced was afterwards measured by removing the iron, but leaving the mag- netising solenoid and the compensating coil in place, and observing the deflection of the magnetometer when the same current was passed through the empty solenoid and the compensating coil. This deter- mined the immediate magnetic effect of the magnetising current on the iron, and the subsequent creeping up of the magnetism was of course determined by observing the drifting of the magnetometer needle which had ensued after applying the current while the iron was in its place. In the following experiment a current of 21 on the arbitrary gal- vanometer scale (equivalent in this case to a magnetising force of 0044 c.¢.s.) was made, after the wire had been completely demagne- tised, and after the compensating coil had been adjusted to balance the immediate effect. Magnetometer readings were taken 5 seconds and 60 seconds after ““make;’’ and at 60 seconds the current was broken, and magnetometer readings were taken 5 seconds and 60 seconds after “break.’’ The immediate effect (balanced by the compensating coil) was equivalent to twenty-five divisions of the magnetometer scale. Time after Time after “make.” Magnetometer. “break.” § Magnetometer, 0 ) 0 13 Bie 8 Bi 5 60" oe 60" 0 VOL. XLVI. X 272 _ Prof. J. A. Ewing. [June 20, Adding to these the equivalent of the compensating coil, we see that just after the immediate magnetising force was suddenly applied, the value of the magnetism was 25, which increased after 5 seconds to 33, and after 1 minute to 38; and that when the magnetising force was suddenly withdrawn, there was at first a residual magnetism of 18, which fell to 5 in 5 seconds, and disappeared altogether in less than 1 minute. Next a current 41 (producing a magnetising force of 0:084 c.g.s.) was made and broken in the same way. The compensating coil scarcely required to be moved from its former position, and its equi- valent on the magnetometer was now 48. The column headed “ total” gives the sum of the magnetometer reading and the part balanced by the compensating coil. Magnetometer. Time after rr Time after “make.” Observed. Total. ‘ break.” Magnetometer. 0 0 4.8 0 31 5” 20 68 a 13 60" ol 79 60” 4 Here out of the whole original residue of 31, a small part refused to disappear after the lapse of a minute, and it is probable that with this magnetising force some of the residual magnetism is permanent. SaaaNa ica ES ee cae a Fe gs \ an 40 scale Atv. Magite tising FOr ceé. The above results are shown in fig. 1 where the arrows indicate the sequence of magnetic changes. One scale division of the magneto- meter is here equivalent to 00177 c.g.s. units of ¥ (intensity of © 1889.] = On Time-lag in the Magnetisation of Iron. 273 magnetism). The magnetic force due to the solenoid may be taken as approximately equal to the whole magnetic force (although the rod was barely 100 diameters long, this length should be sufficient to approximate to endlessness when one is dealing with very low values of magnetic susceptibility). On this assumption, one scale division of the galvanometer is equivalent to 0°0021 of 4%; the initial instan- taneous susceptibility, that is, the gradient d¥/d%, is 9-9, and the initial instantaneous permeability (d®/dH) is 125. This value has been confirmed by a number of independent observations made with the same piece of annealed wire, and with another piece cut from the same hank and also annealed. Taking the magnetism acquired after 1 minute, the initial susceptibility as regards that is about LO. Precisely similar results have been obtained by reversing feeble magnetic forces. So long as the forces are very small, the compensa- tion for ‘‘reverse”’ is the same as for “‘make” and for “ break,” and the creeping of the magnetism in any given time after make, break, or reverse is nearly proportional to the amount of the preceding change of magnetising force. In the following experiments the magnetising force was raised to higher values, at which this proportionality no longer held good. As before, the compensating coil was adjusted for each current to balance the effect of ‘make,’ the iron beig demagnetised by reversals immediately before the “make.” When a stronger current was applied, the coil had to be pushed nearer the magnetometer: but up to forces of 0°3 c.g.s. or so, it was practicable to secure an instan- taneous balance by doing so. Observations of the drift were taken at 5 and 10 second intervals during 1 minute.* These are given Table I. Current. Time after “ make.” 27 | 62 110 161 | seconds. Magnetometer + comp. coil. Oe, thd Chere toie tetas AT 107 224 395 798 Boo sonal uke ae Meptna iene 65 145 304 525 974 MO Beer tates 3) sraleteesatete 2 159 327 560 1071 13 ets Bs ee SP ee 7A, 165 339 573 1089 A eae Re, JA se daa a vi 169 344, 581 1098 25 =) A ae ea 79 171 3847 586 1104 SO es sae te ea 79 173 350 590 1109 Ai tie Fae, Se pel 80 175 354 595 1116 FON eee as eke eae an 80 177 355 598 1120 GO es stoke acer. 5 80 | allay 307 600 | 1124 * To make the drift large the top of the wire was this time only 4 em. from the magnetometer. Kg Q74 Prot Jy Ewing. [ June 20, hie; ale dev. Li S(c.9:8) PSC q > oO fe) 1d. | Kae a3. | N & & Nj ire 2507 71° 0:5C.9.5.uncls on p. 273, the equivalent effect of the compensating coil being added in each case to the actual magnetometer readings. In fig. 2, curves are drawn to show the relation of the current to (a) the immediate magnetisation ; (b) the magnetism after 5 seconds; and (c) the magnetism after 1 minute. The gradient of the curve (a) at and near the origin is the same as that of the corresponding curve in fig. 1, when allowance is made for difference of scales. In the present instance one division of current is 0:0013 of %, and one division of magnetism is 0:008 of J. The gradient begins to increase very sensibly when 4} exceeds about 0-07. Some of the results of Table I are also shown in fig. 3, which gives time curves of the growth of magnetism for the first two stages (currents 27 and 62). Similar curves for the other stages may readily be constructed from the table. It should be noticed that the time 1889. ] On Time-lag in the Magnetisation of Iron. 215 rate of creeping is by no means excessively great in the first instants after contact is made; it is on this fact indeed that the practicability of the method depends. Lo SS BEES habe SEAS ae 2 . Sefer szententastentecttastoits - SEE rae uid Pee FES 6 | CP bs ER Be Sadectantantars ET sevee ECEECEH N ~ ~ Y EN XQ ors ~ ~ dS | Nt S = EPS ha Oo: ae a SS CCRC eGee eee ae PoPeh bakek cbt lee ob dee Eh pelstseletee dak Ll : tales xis Pee hss bare Ge REE Lrawerernteil ) Similar differences between the immediate and ultimate increments of magnetism present themselves when the magnetising force is increased step by step. In the following experiment the compensat- ing coil was set so as to balance the immediate effect of a feeble magnetising current. Then such a current was applied, and the creeping up of the magnetism during 1 minute was observed. At the end of the minute the current was increased by a small step, and it was found that the compensation was still correct or very nearly so: in other words that the immediate effect of this small increase of magnetising force bore the same or very nearly the same proportion 276 Prof. J. A. Ewing. | [June 20, to the increment of force as at the beginning of the process of magnetisation. The creep up of magnetism was again observed during a minute: then another small step up of the current was made, and so on. The compensation remained nearly correct for a number of steps, but as the process was continued up the curve of magnetisation, it became apparent that the immediate effect was increasing, in other words that there was under-compensation, and that the compensating coil would have to be moved a little forward if an exact balance was to be maintained. The results of this experi- ment are given below (Table IT), and are exhibited in fig. 4. The magnetising current was increased from one to another of the succes- sive values shown in the table at intervals of 1 minute in each case, by moderately quick movements of the sliding block in the liquid rheostat. The changes of magnetic force were therefore not quite sudden; each of them took perhaps a quarter of a second to complete. Table IT. Immediate Additional increase Total Magnetising current. magnetic of magnetism magnetism a effect of in (after Step. Total. step. 1 minute. 1 minute). 30 30 63 36 99 13 43 27 23 149 12 SY) 26 22 197 12 67 25 35 257 23 90 (49+) (54 381 AZ 107 36 53 470 5) 112 10 22 502 10 122 21 33 506° The step of 23 was too large to have its immediate effect balanced by the compensating coil in the position in which the coil was set. The magnetic effect of such a large step is conjecturally shown by the broken line marked (?) in fig. 4. It will be noticed that the points reached after 1 minute at each step lie well on a continuous curve, which is shown by a dotted line in the figure. In Table II and fig. 4 one scale division of magnetising current is equivalent to 0:00362 c.g.s. units of magnetising force, and one scale division of the magnetometer is equivalent to 0°0177 c.g.s. units of g. The immediate value of d¥/dH is about 10, as before, and this — applies approximately throughout the range of magnetism dealt with here, with a slight increase towards the upper end of the range. Higher up in the curve of magnetisation, however, the immediate effect of a small quick increment of magnetic force is greater, though then (owing to the greater steepness of the curve § and ¥) it bears 1889.] On Time-lag in the Magnetisation of Iron. 277 Fia. 4. sy ca g8 Sue 08USnEe CEE EEE eet a ee on is i i pseale a ZO CRE Re ee [S| ay ls! is] N (0) _ |I40_. Seale\ div OSC. s a smaller proportion to the ultimate cffect. This is well shown in the following experiment (Table III and fig. 5). Table ITI. Magnetising effect. Magnetising current. S ay ~ 0g uN Di aS hurled - Caan a die Pd Are Spree iy PETE Pe 2:0. ee So Magnelising. Force due i Solenord . However small the step is it appears to be followed by a creeping up of magnetism. I have been able to discover nothing which would correspond with the limit of perfect elasticity in straining a solid (if there be any true limit of elasticity), either in the initial part of the process of magnetisation, or after the prolonged application of a constant magnetising force. But the prolonged application of a constant magnetising force produces an effect which is a most interesting anologue of one effect of prolonged loading in a stretched wire. It is well known that when a load (sufficiently great to produce permanent set) is applied toa stretched iron wire, there ensues, with the lapse of time, not only a certain amount of supplementary viscous extension (the analogue of the magnetic creep) but also a quasi-hardening of the metal which becomes manifest when an addition is made to the load.* One effect * Cf. “Roy. Soc. Proc.,’ No. 205, 1880, or ‘Encyel. Brit.,’ art. “Strength of Materials.” ‘J Se ie oe ae tS ep ‘ ny J na “i i tJ 280 Prof. J. A. Ewing. [June 20, of this is that the wire responds with great sluggishness to the additional load, and this sluggishness is greater the longer has been the preceding interval during which the load has been maintained constant. To test whether, in like manner, the prolonged application of a constant magnetising force would produce what may be called magnetic hardening, I have made comparative observations of the time-rate of change of magnetism when a definite small increment of force is applied, the preceding force having been kept constant (a) for a short time and (b) for a Jong time. The result is to show that the process of magnetic creeping after a small step is much slower when the preceding force has been in action for a long time than when it has been in action for only a short time. es The following experiment illustrates this well. After raising the magnetising force to between 2 and 3 c.g.s. units, the compensating coil was adjusted to balance the immediate effect of a small increase of force, this increase being brought about by short-circuiting 1 ohm (out of many ohms) in the magnetising circuit. When the compensation had been adjusted, the iron was demagnetised by reversals, and the magnetising force was again gradually applied. ~When it reached the value of 2°54 c.g.s., a pause was made for 3 minutes, during which time this magnetising force of 2°54 remained constant. The resistance in the circuit of the magnetising current was then suddenly reduced by 1 ohm, which had the effect of raising the force to 2°60. The compensating coil prevented this step-up of magnetising force from having any instantaneous effect on the magnetometer ; but creeping, of course, began at once, and the time- rate of creeping was observed during 10 minutes. ‘Then the magnetising current was kept constant for 60 minutes more, making 1 hour in all, and a second step-up of magnetising force was effected by removing another ohm of resistance: the second step was very nearly equal to the first, and raised the force to 2°66 c.g.s. The time-rate of creeping which followed it was also observed during 10 minutes. The results are shown in fig. 7, where the curve A shows the growth of magnetism during 10 minutes when the step had been preceded by a 3-minute interval of constant force, and the curve B shows the growth of magnetism when a sensibly equal step | was made, which had been preceded by a 1-hour interval of constant - force. The times are in each case reckoned from the instant at which | the step was made, and the increment of magnetism is in each case reckoned from the value reached just before the step was made. The immediate effect of each step (balanced by the coil) was equiva- lent to 51 scale’ divisions of the magnetometer. The creeping-up in. 10 minutes was equal to no less than 531 scale divisions in the case of curve A, as against 820 in curve B. At the place marked with an asterisk in curve A,it happened that the laboratory door was slammed, 1889. | On Time-lag in the Magnetisation of Iron. 281 5 inet Fee [| aa Hera i ari nm “a i ea oa Ea ae eae are | Ree ES eee |e aee Be a a 4 (oe) (e) PEE le dzveston 5) Bee AY SaalBEEitE ERS FP EERE HEE Ba 7 hour. of * 6 mag. force.: ie he See eaee ‘ | = ae hE Ek © ¥ Ma a ess eal ee 5. \ “egg PaaS NCCE RELL in SARA EE NINE pol cele Pole ES es eS a S ~ S a LN} “SO AS) » ~ SS 3 S SS > Ps) eg © » S SN ~\ S e || Leah: eee ra este Ea te Nhe 600 seconds + (for A & 4) which shook the wire very perceptibly and caused a comparatively sudden increase of magnetism (indicated by the dotted part of the curve), after which the time-rate of creeping became specially slow for 1 or 2 minutes: finally, however, the rate appeared to recover from this disturbance. The curves a and 6b of fig. 7 are the first parts of A and B drawn to a ten-fold coarser scale of times. In confirmation of the above, another experiment was made in which the magnetic force was increased by three successive small and very nearly equal steps. The first step was made after 5 minutes of constant force, the second after 1 hour of constant force, and the third again after 5 minutes of constant force. Time-curves of the growth of magnetism were drawn in all three cases. The first and third curves were not far from coincident; but the second curve lay very much below them, as B lies below A. In the experiments to which figs. 4, 5, and 7 relate, the increment of magnetic force whose effects were measured was preceded by increasing magnetic forces: in other words, it was a step-up from a point on the wp curve of magnetisation. I have also examined the effect of a small step-down from a point on the up curve—that is to say, a small decrement of previously increasing force—and find, as ara 282 Prof. J. A. Ewing. [June 20, might perhaps be anticipated from what we knew about static hysteresis, that the immediate effect (dd/d#) of a step-down is decidedly less than the immediate effect of a step-up. When the compensating coil had been adjusted to balance the first effect of a step-up, it was found to give over-compensation for a step-down. Another process has been examined, namely, the alternation of a step-up with step-down, many times repeated. After the magnetis- ing current had been raised to a certain value, it was periodically altered through a definite narrow range by alternately putting im and pulling out the short-circuit plug of a small resistance coil in the main circuit, or by making and breaking a feeble circuit in a second soienoid wound over the first. It was only when this process had been repeated many times that the magnetic effects of the small changes of 4) became approximately cyclic; the early cycles were associated with a progressive rise 1n the intensity of magnetism. But when a nearly cyclic state was reached, the compensating coil could -be adjusted to balance the immediate effects of +64 or —éx, and the same adjustment of course served to balance either. Tested in this way the gradient dgj/d3j (for the immediate effect of 64) after many small + and — steps) has of course a lower value than the gradient which is found when 4 is first raised to H + 69. The latter, as we have seen, is greater when the magnetisation is moderately strong than when there is little or none. The former is nearly constant throughout a wide range of J; its value is approxi- mately the same as at the initial part of the magnetisation curve— namely 10—until the region of saturation is approached, when it becomes distinctly less.* : The periodic changes of magnetism which are brought about by successive small increments and decrements of 4 exhibit a lagging and creeping up and down precisely similar to that which has been illustrated in fig. 1. That figure may serve to show in a general way the relat‘ou of the change of J to the change of 4%, when at any place in the curve a very small increment 64} has been applied and removed often enough to establish a cyclic régime. I have not made any full | examination of the variation which under these conditions the gradient d4/d4} suffers when the magnetism on which the small cycle if superposed is gradually pushed up towards saturation, nor of the proportion which the subsequent creeping up or down bears to that part of the change of J which occurs immediately on the application or removal of 64). The creeping which follows each repeated applica- tion and removal of 64) is certainly much reduced when the iron approaches saturation; but the immediate effect is also reduced, and so far as may be judged by rather rough determinations, it appears * Cf. Lord Rayleigh, foc. cit.,on the approximate constancy of the static gradient dyad. 1889. ] On Time-lag in the Magnetisation of Iron. 283 that the proportion of creeping ‘to immediate effect is much the same with high as with low magnetisation. One may refer, in this connexion, to the energy which is dissipated through hysteresis, in performing a small cycle by alternately applying and removing a very small force 6%. The action is the same in kind whether there is or is not additional magnetisation. The energy dissipated in each cycle is =| aay. and vanishes when the increment and decrement of J go on pari passu with the incre- ment and decrement of 3. Consider now fig. 1. When the repeated cyclic changes of 4 are indefinitely rapid and go on without pause, so that creeping has not time to occur, a single straight (or sensibly straight) line such as OA represents the relation of the change of magnetism to the (very small) change of magnetising force, during both increment and decrement. The rapidity of the action prevents any loop from being formed, and there is consequently no sensible dissipation of energy through hysteresis. This state of things is perhaps nearly realised in the case of a vibrating telephone diaphragm, or, in regard to circumferential magnetisation, by an iron conducting wire in a telephone circuit. Again, let the cycle be performed indefinitely slowly. In that case the magnetism, at every stage of the cycle, creeps up or down toa steady value. A sensibly straight line, such as OB, represents the relation of g to 4 during both increment and decre- ment; and there is again no dissipation of energy. But with any frequency of alternation lying between these extremes of infinitely fast and infinitely slow, a loop will be formed, since the creeping will take effect most considerably at and near the ends of the range (the time-rate of change of 4 being least there), and there will be dis- sipation of energy. When the limits and mode of variation of 4j are specified, there must be some particular frequency which will make the energy dissipated per eyele a maximum. | The phenomena described in the paper have been reproduced in several specimens of annealed iron wire,.of course with quantitative differences. As to the amount of magnetic creeping much depends on the annealing of the specimen. Another piece of iron wire cut from the same bundle as the piece with which these experiments were made, and annealed at another time, showed almost exactly the same susceptibility to magnetism as the first piece, so far as immediate effect went; but in it the subsequent creeping up was decidedly less (in the proportion of about 4 to 5). When the iron is hardened by mechanical strain the phenomena of creeping vanish almost completely. A specimen from the same bundle was annealed, and showed much creeping. It was then put in the testing machine and pulled until it took a sat of 1 or 2 mm. % 284 Prof. J. A. Ewing. [June 20, in a length of 40 cm. or so. It was then examined magnetically as before, and scarcely a trace of creeping could be observed when a feeble magnetising force was applied. When the compensating coil was properly adjusted the making or breaking of the magnetising current caused no more than a slight momentary quiver of the magnetometer needle, followed by no measurable drifting, although the whole magnetic effect (compensated by the coil} was equivalent to a hundred or more scale divisions. When a magnetising force of as much as 0°6 c.g.s. unit was suddenly applied, the amount of creeping, if there was any, was certainly less than 1 per cent. of the immediate effect. With values of 4 higher than this it became possible to detect creep with certainty. The following notes relate to this wire :— Magnetising force suddenly applied. Immediate value (c.g.s.) of J (c.g.s.). 0°75 449 1:28 8°42, crept in 1 min. to 8°58. 2°40 25°5 i 26°4:. These forces were in each case applied to this wire in a neutral state. Another trial of the same, with feebler forces, gave 53 as the value of d4/d¥% for the immediate effect of a very small force, applied when the iron was demagnetised. The same quantity in the annealed specimen was, as has been said, about 10. In fig. 6 the relation of a (immediate) toe 4) as stated above, is represented by the curve OR; the creeping up at the last point is RS. : In speaking of soft iron it has been shown that the effects of creeping are most marked when a small addition 64 is made to a pre- viously increasing force 4. In instances quoted above, the creeping | up in 1 min. has under those conditions been many times greater than the immediate effect of 64). By way of putting the specimen of hardened iron to the same test, I have applied a magnetic force of 1°46 and raised it by a small step to 1:49. The immediate effect of this step (which was balanced by the compensating coil) was equivalent to twenty-two scale divisions of the magnetometer, and this was followed during 1 minute by a creep- ing equal to six scale divisions. In itself this creeping is consider- able, but compared with the corresponding creeping in soft iron it is extremely small. Pieces of steel (containing a good deal of carbon) have also been examined, with the result that whether the steel be annealed or in its commercial temper the phenomenon of creeping is even less visible than in hardened iron. With annealed steel, a force which pro- duced an immediate (compensated) magnetic effect equal to 124 scale divisions caused barely a single scale division of creeping. With a stronger current, giving an immediate magnetism of 340, the sub- = | j ; | 1889. ] On Time-lag in the Magnetisation of Iron. 2895 sequent creeping was 3. In steel and in hard iron the creeping seemed to be completed in a few seconds after the institution of the magnetising current. The steel specimen, like the iron, had a diameter of rather more than 4mm. Its susceptibility (annealed) was considerably less than that of the iron in the liard state. It is scarcely necessary to observe that the protracted and exten- Sive creeping or magnetic ‘‘nachwirkung” in soft iron which these experiments illustrate cannot be ascribed to the subsidence of the circumferential currents which are generated by the imposition of longitudinal magnetic force. The creeping is equally conspicuous whether the magnetic force is suddenly or graduaily imposed. Lord Rayleigh has shown that circumferential currents started and left to themselves will subside to e~! of their initial magnitude in the time Aa wa? (2404)? ” where a is the radius of the cylinder, » its permeability, and p its specific resistance.* In the present instance, taking the case of the annealed iron rod, a = 0°202, w = 125, » = 9827 (Hverett), and 7 is less than =j455 of a second. The subsidence would be practically complete in a sinall fraction of a second: but the creeping persists during many seconds and even minutes with no excessive change of rate. Again, comparing soft iron with hard iron, in which wp is less and p is greater, the values of 7 will differ, but not by any means so much as to correspond with the very wide difference in magnetic lag. In view of this it is puzzling to find that the diameter of the rod experimented upon has a most important influence on the magnetic lag. In testing various samples of soft iron wire, most of which were of less diameter than the piece used in the above experiments, I noticed that the phenomena of creeping were less marked in the smaller rods. I then tried a bundle of nine very soft annealed iron wires, which were bound together with fine copper wire, and formed a core of about the same length and aggregate diameter as that of the solid rod formerly used. With this bundle there was some creeping, but very little in comparison with what was observed in the solid rod, as the following notes show :— Bundle of nine soft Iron Wires. Magnetometer deflections. ee (es So) aa Magnetic force 4 Immediate (balanced Subsequent suddenly applied by compensating creeping in Total (c.g.s.). coil). min in 1 min. 0-052 17 my 19 19 Q:14:7 52 g 61 * * “Brit. Assoc. Report,’ 1882, p. 446. _ ——————— | | 286 Messrs. J. T. Bottomley and A. Tanakadate. [June 20, Finally, another bundle was built up, consisting of a much larger i number of fine annealed iron wires. With this the creeping was | almost insensible. | It may be that the comparative absence of magnetic creeping, or “ nachwirkung,” in these last experiments is to be ascribed to the i quickness with which the process of creeping completes itself in a finely ; divided mass of iron: in other words, that the process is practically complete ina time much shorter than the period of the magneto- . meter needle. The marked difference in effect between a solid core (a single thick wire) of soft iron and a laminated core (a bundle of fine wires) of the same material, suggests that in the former much more than in the latter the process of creeping is retarded by the eddy currents which are set up by those molecular movements in which the process itself consists. [July 1lth—In seeking an explanation of the difference in beha- viour it may be worth while to bear in mind that there is probably a ) considerable difference in molecular structure between a solid core and a laminated core of iron. If we accept the view that the mag- 4 netically neutral state is due to the molecular magnets forming closed rings, these rings will for the most part be closed within the limits of the separate constituent pieces of the laminated core, whereas in the solid core they may be much larger, their dimensions being limited only by those of the core itself. | I have received very valuable help in these experiments from two students, Mr. David Low and Mr. William Frew, who have prosecyted a troublesome research with much patience and zeal. Ii. “ Note on the Thermo-electric Position of Platinoid.” By a J. T. BotToMuEy,: M.A., F.R.S., and A. TANAKADATS, & fiigakust. Received June 134, 1889. | i In carrying out a series of experiments on radiation of heat by | solid bodies, an investigation to which one of the present writers has 5 for some time past devoted considerable attention, it became neces- ! sary, for a purpose which need not here be detailed, to select a thermo-electric pair of metals, of which one metal is essentially platinum, as it passes through glass. Various pairs were considered, ae and some trials were made; and it was finally determined to make ' use of platinum and platinoid. The latter metal is an alloy whose electrical and mechanical properties were investigated some years ago by one of the present writers;* and since that time it has * J. T. Bottomley, ‘Roy. Soc. Proc.,’? 1885, 1889.] Note on the Thermo-electric Position of Platinoid. 287 assumed considerable importance in the construction of electrical instruments and resistance coils. Partly on this account, and partly from present requirements, it became both interesting and necessary to determine the thermo-electric constants for a specimen of this alloy. Platinoid is in composition very similar to German silver. In the manufacture of the alloy, however, phosphide of tungsten is em- ployed; and although an exceedingly minute quantity of metallic tungsten remains in the alloy, yet the properties of the substance are in many respects remarkable. The metal is capable of being polished so as to be almost as beautiful as silver in appearance, having only a slightly darker and more steel-like colour; and when it has been polished it remains absolutely untarnished, even in the atmosphere of a large town, for years at any rate. It has very remarkable proper- ties as to electric resistance. It possesses a very high resistance, while at the same time it has a much lower temperature variation of electric resistance than any other known metal or alloy. It has also, as Sir William Thomson has found, very excellent elastic qualities. Although it is not proposed to use the platinoid with any metal other than platinum in the investigation on thermal radiation above referred to, it nevertheless seemed advisable, when these experiments were being undertaken, to determine its position with respect to some other metals. It was accordingly tried as a pair with platinum, iron, aluminium, and with two specimens of copper. A low-resistance Thomson’s reflecting galvanometer was specially prepared for the purpose of these experiments. The mirror was a plane parallel mirror of very excellent quality by Steinheil of Munich. Its deflections were observed by means of a telescope with cross-wires and scale, instead of by a lamp and scale. To avoid any influence of the suspending fibre (which even though of single cocoon silk fibre does with short fibres give an appreciable torsional resistance) the mirror was suspended by spider line. The suspending of a mirror, weighing with its magnet 0:2 gram, by a single spider line is a matter of some nicety and difficuity ; but when it has been accomplished the result is so thoroughly satisfactory that it is easily admitted to be well worth a morning’s labour. To make the suspension two small pieces of very thin bristle or of hard-spun silk fibre or split horsehair are attached to the ends of a suitable length of spider line recently spun by a good large* spider. By means of these attachments, which are easily seen, the spider line can be handled. Itis then brought over the galvanometer mirror ; and great assistance is experienced in these operations, and in opera- tions with single silk fibres, by performing them on the top of a piece of looking-glass laid on the table. The illumination from beneath of | * The body about as large as a pea. VOL. XLVI. » : Y 288 Messrs. J. T. Bottomley and A. Tanakadate. [June 20, the fibres makes it easy to do with these fine filaments that which is otherwise scarcely possible. The fibre is attached to the galvano- meter mirror with the smallest possible speck of shellac varnish, the greatest care being taken not to varnish any part of the spider line. When the varnish has dried, the mirror can be lifted up by the spider line ; caution being used at the moment of raising the one mirror off the surface of the other on account of the vacuum which is liable to be formed at the moment of separation. The mirror should be allowed to hang on the fibre inside a glass beaker for twenty-four hours at least, as the spider line stretches considerably for some time after the weight comes on it. A spider line which will carry a galvanometer mirror and magnet weighing 0°2 gram may have, according to an estimate made by one of the present writers, about -4, of the torsional rigidity of a single cocoon silk fibre. For the heating of the junctions, a number of glass vessels were blown, resembling the flasks, with neck and condensing tube, used for fractional distillation, but with the condensing tube projecting upwards into the air, so that the steam of a liquid boiling in the flask runs back into the flask on being condensed. Into the shorter neck of the flask was introduced a cork, which carried the thermo- junction and a mercurial thermometer; the thermo-junction being loosely bound to the bulb of the thermometer, or, at any rate, kept in close contact with the middle part of the thermometer-bulb. The cool junction was bound to the bulb of a second thermometer, which dipped into a vessel containing water at the temperature of the laboratory. The water was kept thoroughly stirred from top to bottom by a properly arranged stirrer. In the heating flasks the vapours of the following liquids were used : alcohol, water, chlorobenzol, aniline, methyl salicylate, and bromo- benzol.* The liquids were boiled vigorously, and the temperatures of the vapours were determined by means of the mercurial thermometer. Both the mercurial thermometers were compared directly with the air thermometer.t The obtaining of a set of points of temperature by this means was very satisfactory in every case except that of the liquid of highest boiling point, bromobenzol. In this case a curious phenomenon was observed.{ In spite of the fact that the vapour of the substance was rushing strongly into the condensing tube and, indeed, out into the open air, at an elevation of 2 feet above the surface of the liquid it was found exceedingly difficult to keep the temperature of the various parts of the boiling flask anything like uniform. The vapour formed itself into layers of different temperatures, the parts of the flask nearest the surface of the liquid being the hottest. At * Ramsay and Young, ‘ Chem. Soc. Journ. (Trans.),’ 1885. — + J.T. Bottomley, ‘ Phil. Mag.,’ August, 1888. { Perhaps due to want of purity of the substance. EE AGRI 5 Be i Ce ee Oe ee Dp OnE eld 1889.] Note on the Thermo-electric Position of Platinoid. 289 a height of 24 inches above the surface of the liquid the temperature was often found to be as much as 8° or 10° C. cooler than it was just above the surface. The difficulty could, to a certain extent, be over- come by putting a cloak of fine flexible wire gauze all round the upper part of the flask; but the greatest watchfulness was needed to avoid mistakes. In order to reduce the results obtained from the readings of the galvanometer to absolute electromagnetic measure, a carefully pre- " pared standard Daniell’s cell was kept with its current always flowing through a known high resistance; and from time to time the galvano- meter which was being used was thrown into the circuit, and the value of the galvanometer deflection determined. The electromotive force of the Daniell’s cell was valued at 1:072 volts. The results obtained are shown in the accompanying curves and tables, me rome an onuew4 eeegenc Up Amel eee te nae Tee ice 7) VEEL Ea ee ce Tt ei | TT eae TI Li7riz Es TOT a ei [ae inp 4s:Ceudeee pee ce adeeeee ance? see Li lectronotcve Horce tr CGS. In the curves the electromotive forces are shown as ordinates, the differences of temperature between the hot and cold junctions being indicated on the axis of abscissas. The electromotive forces are given ¥ig 290 Messrs. J. T. Bottomley and A. Tanakadate. [June 20, in C.G.S. units, and must be divided by 108 if it be desired to reduce them to volts. The differences of temperatures are given in centi- grade degrees. The direction of the current in each of the cases represented, is from platinoid to the second metal of the pair thro the hot junction. Table I shows, in the way now well known,* the multiplier, at any temperature seneeoncle. which must be used, as factor with the difference of temperatures between the hot and cold junctions, in order to calculate the electromotive force in C.G.S. units. The | algebraic sign corresponds with that used by Tait, and now adopted by Everett (‘ Units and Constants,’ 2nd Edition, 1886). Table I. Platinord-platmums 2. i. sen —925—1:16 xt. Platinord 2a lamina sees. nooks —985—4°31 xt. Platinoidsi nonties sa vvompepcenenaiineenstccsinnu —2916+0°86 xt. Platinoid-copper:(&:)'o. 4 2 6 — 1246 —5°44 x ¢. Platinoid-coppe: (3)'2.. 4. a —- 1294 —4°88 x t. Combining the results of Table I with those of Tait, reduced by Everett, we obtain the thermo-electric distance of platinoid from lead, taken as zero, at various temperatures centigrade. If any one of the wires platinum, aluminium, iron, or copper used by us, were identical with the wire of the same name used by Professor Tait, we should be able to deduce with exactness the distance of our platinoid wire from his lead wire. That, however, was not the case; and each of the secondary wires used by us gives us, as it were, a different result. Thus we have :— Table II. Platinoid to lead. From experiment with platmum ...... —986—2°26x¢ = is alumina 65.2 —1062—3°92 xt 7 3 AHO araiienss esd j3he —1182--401 x¢ 55 x copper (A) .... —1110—449xz : ': copper (B) ..... —1158—3:93 xz Taking the mean of all of these, with the exception of the result for platinum, which we omit because different specimens of platinum are well known to differ thermo-electrically enormously among them- selves, we obtain for the thermo-electric distance of platinoid from Professor Tait’s lead wire —1128—4'1 x ¢. This result enables us to place platinoid in Tait’s thermo- electric diagram. Its line is nearly parallel to those of palladium and German * Tait, “ Edinburgh Roy. Soe. Trans.,’ vol. 27, 1873, and Hverett’s ‘ Units and Constants,’ 2nd Hdition, 1886,—“ Thermoelectricity.”’ 1889.] Note on the Thermo-electric Position of Platinoid. 291 : silver, and slightly above the latter. It is, however, to be re- membered that,in all probability, different specimens of platinoid alloy would give results differing considerably from that quoted above. Appendix. By A. ‘TANAKADATE, The following experiment on the torsional rigidity of spider line was carried out in the Physical Laboratory of the Imperial University of Japan, in 1884, and a notice of it was published in vol. 2 of Tugakukyokwat Tassi (‘Proceedings of the Science Society’) of that year in Japanese. It has not hitherto been described in English; and the absolute determination as referred to below by Mr. 'T. Gray of the rigidity of silk fibre makes an estimate of the rigidity of spider line possible. The determination of the torsional rigidity was a relative one, and the experiment essentially consisted in finding the deflection of a small magnet due to a given twist of the suspending fibre: the magnet being placed in the earth’s magnetic field (0°3 C.G.S.). The deflection was observed by the usual method of the reflected image of a fine wire stretched before a lamp. 3 The mirror magnet was first hung by a silk fibre of 31 cm. length, and placed in the usual way. The distance of scale from the mirror was 95cm. When the torsion head of the magnetometer was turned through one complete revolution (27) in either direction from zero, the image of the reflected wire was displaced through 8 mm. either way, or 8/2 x 95=0:0042 radians, or 864”. The silk fibre was now detached from the magnet, and a spider’s line (newly spun) was attached in its stead. The length was 28 cm., the magnetometer was put into its place, and the torsion head was turned as before, but no appreciable deflection could be observed, even when the torsion head was turned through ten complete turns (207). It was suspected then that the mirror might have been caught against the sides of its case; a close inspection, however, showed that it was quite free. The fibre was then shortened to 2:3 cm. (about one-twelfth its previous length), and the experiment was re- peated. Ten complete turns of the torsion head gave a deflection of 15 mm.; or 15/2 x 95 = 000079 radians = 16°3” per turn. In order to compare these deflections with each other, each deflec- tion was reduced to that which would be given by a fibre of 1 cm. in length, by multiplying the deflections by the length of the fibre used. Thus, corresponding to the twist of one turn of the torsion head in a fibre of 1 cm. long, we have :— 8640” x 81 = 26800" 168! X23 =a" ea a 292 Prof. J. J. Thomson. | [June 20, From this we get the ratio of the torsional rigidity of the spider line to that of the silk fibre to be 1: 710. The diameters of the fibres were microscopically measured, and gave the following values :— Silk Nbr: 2.12 eee ei eee 0:00091 cm. Spider dine 2.4) pees = cece toe 000028 _,, If the elastic qualities of these fibres were the same, the ratio of the torsional rigidity would have come out (28)* : (91)4, or 1 : 112; and hence the torsional rigidity of spider line is less than one-sixth | of that of silk fibre of the same thickness. | The above result gives us only a relative value of the rigidities | between the two fibres. If we take the mean value of the torsional | rigidity of silk fibre to be 0°0012 C.G.S. on a length of 1 centimetre (not per square centimetre), as found by Mr. T. Gray,* the tor- sional rigidity of the spider fibre of the above experiment will be 0:0012 1 a0 0:000002 C.G.S., the mode of reckoning bemg the same. Mr. Gray’s silk fibre may have had a slightly higher rigidity, as he states that it was boiled in water, while the fibre of the experiment just described was taken from those boiled in dilute potash water, as is the usual practice of preparing “‘ mawata,” which isa very soft kind of silk. IV. “Specific Inductive Capacity of Dielectrics when acted on by very rapidly alternating Electric Forces.” By J. J. | THomson, M.A., F.R.S., Cavendish Professor of Physics, | Cambridge. Received June 17, 1889. The researches of Dr. John Hopkinson have shown that in some dielectrics, of which the most conspicuous example is glass, the refractive index is not, as it ought to be on Maxwell’s theory, equal to the square root of the specific inductive capacity, when the latter is measured for steady forces, or such as are reversed only a few thousand times a second. It is therefore desirable to measure the inductive capacity under circumstances which approach as nearly as possible to those which, according to Maxwell’s theory, occur when light passes through a dielectric. This will be when the forces are reversed as rapidly as possible. In the following experiments the forces were reversed about 25,000,000 times per second. | ; The method consists in measuring the wave-length of the electrical vibrations given out by a condenser whose plates are in electrical connexion. If C is the capacity in electrostatic measure of the con- * € Phil, Mag.,? 1887. 1889. ] Specific Inductive Capacity of Dielectrics. 293 denser, L the coefficient of self-induction in electromagnetic measure of the circuit connecting the plates of the condenser, the wave-length, if it is long compared with the length of this circuit, equals 27./(LC). Thus, if we can measure the wave-length of the vibrations executed by such a system, we can find the specific inductive capacity of a dielectric. For, if we determine the wave-length of the system first when the plates of the condenser are separated by air, and then when they are separated by a slab of the dielectric whose specific inductive capacity we wish to measure, the ratio of the squares of the wave-lengths will be the ratio of the capacities of the condenser in the two cases, and if we know this ratio we can deduce the specific inductive capacity of the dielectric interposed between the plates. vena The arrangement of the experiment was as follows :— The condenser consisted of two circular zinc plates, AB, CD, 30 cm. in diameter; these were supported on an insulating stand, and -the distance between them could be altered at pleasure. To these plates wires, EF’, GH, each about 25 em. in length, terminating in the highly polished balls, F, H, were attached. The plates were also connected with the poles P, Q, of an induction coil, and when this was in action a succession of sparks passed between the balls F and H. The periodic distributions of electricity thus produced over the plates sent electrical waves down two insulated wires, each about 20 metres in length, attached to the small zinc plates, L and M, placed close to the plates of the condenser. The wave-length of the vibrations transmitted along the wire was determined by the method I described in a former paper (“‘ Note on the Effect produced by Conductors in the Neighbourhood of a Wire on 294. Prof. J. J. Thomson. [June 20, iG. 2: the Rate of Propagation of Hlectrical Disturbances along it,” ‘ Roy. Soc. Proc.,’ vol. 46, p. 1). Two wires RS, VW, of equal length, had the ends S and W fastened to the poles of a spark micrometer, while the other ends, R, V, could slide along the wires LT, MU respectively. At first R was placed at T, and V was moved until the sparks in the micrometer were as smail as possible ; suppose that « was the position of V when this was the case. T and « will be at the same potential. The end V was now kept fixed at a, and R moved until the sparks again became as faint as possible; suppose that 8 was the position of R when this was the case, then 6 and a, and therefore B and T, are at the same potential; so that, since T is a place of maximum potential, PT equals a wave-length. By starting from #6 and proceeding further up the wire we can get another determination of the wave-length. Since from the nature of the case other conductors besides the two disks were in the field, the capacity of the condenser was in excess of the value given by the formula 8/47t, where S is the area of one of the plates and ¢ the distance between them; but this is the only part of the capacity which is increased when the slab of dielectric is inter- posed between the plates. The capacity when the disks were 2 cm. apart was determined by the tuning-fork method given in Maxwell’s ‘“ Hlectricity and Magnetism,” vol. 2, p. 385, and was found to be 1889. ] Specific Inductive Capacity of Dielectrics. 295 40 in electrostatic units; the formula §/47t would, where S = 7x15? and t = 2, give 28, so that of the 40 units of capacity, 28 are due to the two disks and 12 to the presence of the other con- ductors. This was verified by determining by the tuning-fork method the capacity of the condenser when the distance between the disks had a series of values. When the distance between the disks was 2 cm., the mean of several determinations of the wave-length along the wire was 8:25 metres. The value calculated by the formula 27./(LC), where C = 40 and i 2) (Jog ——2) where J = length of circuit (supposed circular) T = 50 cm., and d the diameter of the wire = 0°3 cm., is 8 metres. When the plates were separated by pieces of plate glass 2 cm. thick, the wave-length was 11°75 metres. Thus, if K is the specific inductive capacity of the glass, agen ge eK ele ie Ope Wie AG ? Ke and. 4/7 K = 1 "65. The determination of the specific inductive capacity of the glass by the tuning-fork method was difficult, owing to electric absorption; the values for K obtained in this way varied between 9 and 11. We see, therefore, that for vibrations whose frequency is 3 x 10!0/11°75 x 10?, or 25,000,000 per second, the specific inductive capacity is very nearly equal to the square of the refractive index, and is very much less than the value for slow rates of reversals. The discrepancy is pro- bably due to the cause which produces the phenomenon of anomalous dispersion in some substances, and indicates the existence of molecular vibrations having a period slower than 25.000,000 per second. The behaviour of the glass under electrical oscillations of the critical period would form a very interesting subject of investigation. ‘The specific inductive capacity of ebonite was determined in a similar way; the wave-lengths, when the plates were separated by air and ebonite respectively, were 8°5 metres and 10°75 metres, giving as the specific inductive capacity of ebonite 1:9. The value determined by the tuning-fork method was 2°1. The specific inductive capacity of a plate made of melted stick sulphur was also tried: the wave-length without the sulphur was 8°25, with it 11°5, giving as the svecific inductive capacity of sulphur 2-4. The value determined by the tuning-fork method was 2:27. Thus, for ebonite and sulphur the values determined by the two methods agree as well as could be expected, while for glass the results are altogether different. 296 Messrs. L. Mond and C. Langer. [ June 20, V. “A new Form of Gas Battery.” By Lupwic MonpD and CARL LANGER. Communicated by LorD RAYLetIcuH, Sec. B.S. Received June 13, 1889. In January, 1839, now over fifty years ago, Mr. (now Lord Justice) Grove published the first notice* of his startling discovery—the gas battery. This he followed up in 1842, 1843, and 1845 by three important papers}, two of which were read before this Society. Since that time very little attention has been given by investigators to the subject. Papers by Schonbein,t De la Rive,§ Matteucci,| Beetz, Gaugain,** Morley,tf Peirce,t{ Lord Rayleigh,§§ Figuier,]|||| and Kendall, and a few patents describing ingenious but imprac- ticable suggestions for improved gas batteries, comprise the principal contributions to the subject. This is the more surprising as Grove had published a large number of experiments leading, amongst other important results, to a complete list of the voltaic relations of gases to each other and to other substances, and had pointed out in his lucid manner the great scientific interest attaching to the gas battery, which forms the simplest instrument for generating electricity, possesses remarkable constancy of E.M.F., and ‘‘ exhibits such a beautiful example of the correlation of natural forces.” Grove states that he never thought of the gas battery as a practical means of generating voltaic power, but, nevertheless, he indicates clearly in what directions improvements with this object should be attempted, viz., by extending as much as possible the surface of contact between the gases, the absorbent and the electrolyte. We have been engaged for several years with investigations on gas batteries, which fully corroborate Grove’s view, but show that he, as * Grove, ‘ Phil. Mag.,’ vol. 14, 1839, p. 129. + Grove, ‘Phil. Mag.,’ vol. 21, 1842, p. 417; ‘Roy. Soc. Proc.,’ vol. 4, 1843, p- 463; vol. 5, 1845, p. 557. ~ Schénbein, ‘ Poggendorff, Annalen,’ vol. 56, 1842, pp. 135 and 235; vol. 58, 1843, 361; vol. 62, 1844, 220; vol. 74, 1849, 244. § De la Rive, ‘ Arch. d’Electric.,’ vol. 3, 1843, p- 525. || Matteucci, ‘ Comptes Rendus,’ vol. 16, 1843, p. 846. {| Beetz, ‘ Poggendorff, Annalen,’ vol. 77, 1849, p. 505; vol. 90, 1853, p. 42; vol. 132, 1867, p. 460; ‘ Wiedemann, Annalen,’ vol. 5, 1878, p. 1; ‘ Phil. Mag.,’ wol.//, 1879, 'p. 1. ** Gaugain, ‘Comptes Rendus,’ vol. 64, 1867, p. 364. tt Morley, ‘ Phil. Mag., vol. 5, 1878, p. 272. ff Peirce, ‘Wiedemann, Annalen,’ vol. 8, 1879, p. 98. §§ Rayleigh, ‘Cambridge Phil. Soc. Proc.,’ vol. 4, 1882, p. 198. \||| Figuier, ‘Comptes Rendus,’ vol. 98, 1884, p. 1575. “(| Kendall, ‘ Roy. Soc. Proc.,’ vol. 36, 1884, p. 208. 1889. ] A new Form of Gas Battery. 297 well as later investigators, overlook one important point, viz., the necessity of maintaining the condensing power of the absorbent unimpaired. We found that platinum. black, the most suitable absorbent for gas batteries, loses its condensing power almost com- pletely as soon as it gets wet, and that it is therefore necessary for our purpose to keep itcomparatively dry. All attempts to attain this with various constructions of the gas battery involving the use of a liquid electrolyte failed. We have only succeeded by using an elec- trolyte in a quasi-solid form, viz., soaked up by a porous non-conduct : ing material, in a similar way as has been done in the so-called dry piles and batteries. In order to procure as large a contact as possible between the gases, the electrolyte and the absorbent, and at the same time to obtain the greatest possible duty out of a given quantity of the latter, we have adopted the following construction :— A diaphragm of a porous non-conducting substance, such as plaster of Paris, earthenware, asbestos, pasteboard, &., is impregnated by dilute sulphuric acid or another electrolyte, and is covered on both sides with thin perforated leaf of platinum or gold and with a thin film of platinum black. The platinum or gold leaf, which serves as conductor for the generated electricity (the platinum black being a very bad conductor), is placed in contact at small intervals with strips of lead or other good conductor in order to reduce the internal resistance of the battery toa minimum. In place of the platinum or gold leaf, fine wire gauze of the same metal or of carbon may be used. The diaphragms so prepared are placed side by side or one above the other, with non-conducting frames of pasteboard, wood, india- rubber, &c., intervening, so as to form chambers through which the gases to be employed (generally hydrogen and air) are passed, so that one side of the diaphragm is exposed to the one gas and the other to the other gas, and the spaces between the diaphragms are so con- nected that these gases pass in contact with a number of diaphragms. Of the numerous ways in which dry gas batteries can be con- structed we will describe two. One of these constructions, suitable for laboratory work, shown in fig. 1, consists of an earthenware plate M, impregnated with sulphuric acid and cemented into an ebonite frame R. At a short distance from and all around the plate a copper wire A is let into the ebonite frame. The earthenware plate is covered with platinum leaf which has been perforated with a very large number (1500 per square cm.) of small holes, and which extends over and is in metallic contact with the copper wire. To protect the latter from corrosion, and to avoid local action, molten paraffin is put over the platinum leaf where it is in contact with the copper wire. Where the platinum leaf is in contact with the earthenware plate it is coated by 298 Messrs. L. Mond and C. Langer. [June 20, frees: E , oS vi eae 71 i i WY i Ss aha Em C 1 A means of a brush with a very thin film of platinum black, which penetrates through the pores and holes of the platinum leaf, and thus comes into contact with the electrolyte. The frame R is fixed by means of screws between the two ebonite plates HE, E’, with two india-rubber frames K, K’ intervening, thus forming two gastight chambers G, G', through which the gases to be used are let by the tubes O, O’ and H, H’. WSs SS «* x WLU “UUM VM. * ww WY a. WMA iy q WY —— LUE. ro Wii Ua Ll ~ WWWY// IIL Wu Yllligys LR WML. ETE a Li — Ml Ul LN ae —— —— a MMM NK MMM SL Mus“ YM“ ae YILSSSS ——— MMMM yy aoe WML i MU FTTITSS WW MN WW UL Ze Zep Fs MMM == VM ZOOS ANON eo VIR YUM WOK WMD EOE Tk Tf LMM ie . AWW VU MMU bbb = S - SW ww WIM UMM é ASL VM: LLL : NAGA & SG RNMMMMMMMMAN = TNO OMA K R J A an J ze SS ~YYia The second construction consists of a number of elements each of which is composed of two frames of lead and antimony consisting of a broad edge R, conducting strips A, and flaps F with holes and channels O, H, which form the inlets and outlets for the gases. These frames are coated with an insulating layer a of a mixture of gutta- percha, beeswax, resin, and paraffin. Between the two frames we insert a thin sheet S, prepared by coating a piece of cloth with plaster of Paris, and made impervious round the edges by the same insulating mixture, and then the open spaces formed by the conduct- ing strips A are filled up with plaster of Paris mixed up with dilute sulphuric acid, so as to obtain an even plate. Thisis now coated with platinum leaf and platinum black in the same way as before described. A number of these elements are put side by side or one above the other, with non-conducting frames K of pasteboard intervening, so as to i j =_ iF - - 7 ’ ae yf: ' a oH tt alia | OF : A . Z G 5 ath al oT i H ‘ \ | ae chambers G,, G5, Gz, which are connected by means of c rubber wa an rs Q, s o that the gas eee the pipes 0. pas oe ough the oe s of Bs ee The first and the la st gas chamber are fo mnsdpaed sdditens ae: asteboard frame interve between the ‘a aca and two plates of zinc ZG, Aa, ae beyond the battery plates, which hold the ects ieeaiie: . The whole 300 Messrs. L. Mond and C. Langer. [June 20, set of plates is now coated on the four sides not covered by the zine plates with a mixture of beeswax and resin, so as to obtain a block which is perfectly gastight all round, and the space V left between the two zinc plates is then filled up with plaster of Paris, so as to obtain one solid compact block with no openings except the entrances and exits for the gases. This is closed by four more zinc plates, Z., Zi, Z:, Ze, which are soldered together so as to form a box. The E.M.F. of this battery we found to vary considerably, accord- ing to the way in which the platinum black is prepared. The best and most regular results we have obtained from platinum black made by neutralising a boiling solution of PtCl, with Na,CO., and adding this slowly to a boiling solution of sodium formiate. With this we obtain an electromotive force of 0°97 volt with the open circuit. The internal resistance varies considerably with the thickness of the porous plates, the amount of the electrolyte contained in these, and the surface of these plates. Plates of gypsum of 8 mm. thickness and 350 cm. surface gave an internal resistance of 0:02 ohm. The current obtainable from these batteries varies necessarily with the external resistance. It is possible to obtain 8 ampéres from one such element, but the H.M.F. of the battery sinks at a very much more rapid rate than with constant batteries if a strong current is taken out, and the work done by the battery is not, as in constant batteries, at its maximum when the internal and external resistance are equal. Thus we found with a small battery of 42 sq. cm. surface and 0°36 ohm internal resistance the following results :— | ao ce R, P S E. Ey D A 0°360 | 0°30 0: 265 0:883 | 0°62 | 0°58 | 0-04 | 0-236 a 0°40 0°310 0-775 | 0:62 | 0°58 | 0°04 | 0-240 ae 0°70 0-430 0-614 | 0°67 | 0°65 | 0-02 | 0-263 ie &:; 1:00 0-490 0-490 | 0-68 | 9°66 | 0:02 | 0-240 . 2-00 0° 605 0-302 | 0°72 | O-F1 | 0-01 "onze : 4-60 0-700 0-175 | 0°77 | 0°76° | 0701 7] Geiee 8-00 0-786 0-097 | 0°81 | 0-81 | 0:00 | 0-075 Sy ee 20°00 0-860 0-048 | 0°87 | 0°87 | 0-00 | 0-036 Internal resistance in ohms. . External resistance in ohms. Difference of potential at the poles. Strength of current in ampéres. E.M.F. in volts, determined by the first deflection of the galvanometer needle 1 second after opening the circuit. . Calculated E.M.F. in volts. Difference of E and E, = increase of E.M.F. during 1 second, showing rapidity of absorption of the gases with varying saturation of the platinum. Work done by the battery in watts. to) I foe: Be ee | 1889. ] A new Form of Gas Battery. 301 These figures show that in the case of the battery experimented with the maximum of work was obtained with an external resistance of about double the internal resistance. This result is probably due, as pointed out by Dr. C. A. Wright,* to the fact established by Favret and Berthelot,t that the gases occluded or condensed by platinum black evolve less and less heat per unit weight of gas the more gas the platinum black had pre- viously condensed. The heat evolved by the condensation of the gases by the platinum black, or a certain portion of this heat, is in all probability lost for the production of the current; it follows that the more the platinum black is saturated the less energy will be lost by the condensation of the gases, and vice verst. Now, probably the rate of absorption of gas by the platinum black will rapidly diminish as it is more and more saturated with gas, so that in order to maintain it saturated or nearly saturated only a moderate amount of current can be obtained from a given surface, while if it is kept far below the saturating point it will condense the gases very rapidly, and a very large current can consequently be obtained. As a practical limit we prefer to work the battery with an E.M.F. with closed circuit of about 0°73 volt. This allows us to take from 2 to 24 amperes (1°45—1°82 watt) out of an element with an active surface of 700 sq. cm., covered with 0°35 gr. of Pt leaf and 1 gr. of Pt black, which gives a useful effect of very nearly 50 per cent. of the total energy contained in the hydrogen absorbed in the battery. We have found practically no difference in these results, whether we were using O and H or air and gases containing 30 per cent. to 40 per cent. of H, such as can be obtained by the action of steam or air and steam on anthracite, coke, or coal. With a useful effect of 50 per cent., one-half of the heat produced by the combination of the H with the O is set free in the battery, and raises its temperature. By passing through the battery a sufficient excess of air, we can keep the temperature of the battery constant at about 40° C., and at the same time carry off the whole of the water formed in the battery by means of the gases issuing from it, so that the platinum black is kept sufficiently dry, and the porous plate in nearly the same state of humidity. The H.M.F. of the open battery is very considerably below what it should be according to Thomson’s theorem. The combustion of H and O should produce an H.M.F’. of 1:47 volts, while we only obtain 0°97. It does not seem to us probable that this difference can be explained in the same way as the deviations from this theorem in a number of eS Bhnls Miao volo PSsie pul Go: + ‘Comptes Rendus,’ vol. 77, 1878, p. 649. ft ‘ Annales de Chimie,’ vol. 30, 1883, p. 519. 302 Messrs. L. Mond and C. Langer. [June 20, abnormal voltaic batteries have lately been explained by Chroustchoff and Sitnikoff,* viz., by the Peltier effect, which would probably not be different for the combinations HPt,SO,H, and SO,H,,PtO; nor do the causes by which Herrouny explains this deviation appear to us to be applicable to the gas battery. It seems more probable—and what we have stated above respecting the rapid loss of the E.M.F. when taking out larger currents favours this view—that this loss of energy is to some extent due to the heat given out in the condensation of the gases by the platinum black. Favret found the heat given out by the condensation of 1 gram of H by platinum to vary from 23,000 to 13,000 calories, and concluded that this condensation was analogous to the condensation of carbonic acid by carbon, a purely capillary action. He did not determine the heat of condensation of oxygen. Berthelot§ found the heat of condensation of H by platinum to vary per gram of H condensed from 17,000 to 8700 cal., and concluded that the H formed two distinct combinations with the platinum, the first taking place with a disengagement of 17,000 cal., and then com- bining with another equivalent of H with a disengagement of 8700 cal. Berthelot also attempted to determine the heat given out by the absorption of O by platinum, which gas he found to be absorbed only in very small quantities, so that he could not determine the caloric effect with any amount of certainty; but he calculates it from the figures he obtained at at least 17,000 cal. for 8 grams of O. But these figures would lead to a much larger loss of energy than we find actually to take place. According to Berthelot, the condensation by platinum of 1 gram of H and 8 grams of O produces 25,700 to 34,000 cal. We obtain in the battery out of 34,187 cal. (resulting from the combina- tion of 1 gram of H with 8 grams of O) 23,512 cal. as electricity, thus losing 11,666 cal. Weare engaged upon an investigation of this rather difficult subject, with a view to further elucidating its effect upon the gas battery. The fact that PdH, which, according to Favre,|| is formed with an evolution of only 4150 cal. per 1 gram of H (a figure which agrees fairly well with that obtained by calculation from the tension of PdH), produces, if opposed to PtO, a smaller H.M.F. than PtH, has also to be considered in studying this question. Using Pd black on gold foil opposed to Pt black on Pt foil in our battery, we found the H.M.F. PdH,H,SO,,PtO = 0°91 volt, as com- pared to 0°97 volt for PtH,H,SO,,Pt0O. * ‘Comptes Rendus,’ vol. 108, 1889, p. 987. {+ ‘Phil. Mag.,’ vol. 27, 1889, p. 209. ~ ‘Comptes Rendus,’ vol. 77, 1873, p. 649. § ‘Annales de Chimie,’ vol. 30, 1883, p. 519. || ‘ Comptes Rendus,’ vol. 68, 1869, p. 1525. 1889.] A new Form of Gas Battery. 303 In the hope of throwing some light upon the question of the disappearance of energy in the gas battery, we have determined the E.M.F. of the following combinations by means of a block of plaster of Paris impregnated with sulphuric acid, one end of which was eovered with platinum foil and platinum black and arranged so that it could be exposed to H or O, while the other end was plunged into a beaker which contained the liquid electrolyte and the electrode which we wished to examine. Found. Theory. Difference. PtH,H,SO,.PtO = 097 volt = 22,512 cal.* instead of 34,178 cal.+—11,666. Zn,H2S0,,PtO = 1°77 voltt = 41,078 cal. instead of 53,043 cal. —11,965. Cd,H,S0O,,PtO = 1-425 voltt = 33,171 cal. instead of 44,928 cal. —11,767. Cu,H,SO,,PtO = 0°70 volt{ = 16,245 cal. instead of 27,978 cal. —11,733. PtH, H.SO,,CuSO,,Cu = 0°31 volt = 7,194 cal. instead of 6,200 cal. + 994. PtH,H,SO,HNO;,C =1:19 volt = 27,617 cal. instead of 29,175 cal. —1,558. PtO,H,SO,,HNO;,C = 0-22 volt. These figures show that the loss of energy is very nearly the same per equivalent of O consumed, when PtO is used as the negative electrode, whether PtH, zinc, cadmium, or copper is used as positive electrode, and also that PtH with copper in copper sulphate, or carbon in nitric acid, as negative electrodes, gives nearly the theo- retical E.M.F. It would thus seem as if the loss of energy in the gas battery occurred on the PtO electrode; but the question is undoubtedly a complicated one, and requires further study before an explanation of it can be attempted. This battery differs from all other gas batteries in showing all the characteristics of polarisation after it has been at work for some length of time. It loses within an hour from 4 to 10 per cent. of its H.M.F. As the chemical processes taking place at the electrodes could not explain this, we had to look out for its cause in another direction, and found it to be the transport of the sulphuric acid from the O to the H electrode, resulting in the acid becoming gradually more concentrated on the positive side and weaker on the other, which we have established by analysing the gypsum scraped off below the platinum leaf at both sides. Probably this difference of concen- tration of the acid sets up a counter-current. In order to counteract this disturbing influence and to keep the current constant, we iuter- change the gases in the battery from time to time, say once an hour, so that the current goes in an opposite way through the porous diaphragm, and transports the sulphuric acid back. This necessitates, * 1 Daniell = 25,065 cal. = 1°08 volts. + Calculated from Thomsen’s data (‘ Thermochemische Untersuchungen’) divided by 2, so as to refer to O = 8. ft Wright and Thompson found 1°75, 1°5, and 0°78 respectively (‘ Roy. Soc. Proc.,’ vol. 44, 1888, p. 182). Z VOL. XLYI. 304 Dr. E. Frankland. Contributions to [ June 20 where constant currents are wanted for a longer period, the working | of a number of elements or batteries connected by means of a com- | mutator in such a way that one element or battery will always be out of the circuit, and have its gases changed, and be replaced in the | circuit at the moment when the next element or battery is switched out for the same purpose. In using, in place of sulphuric acid, a solution of sodium chloride as electrolyte, we found, after working the battery for some time, sodium hydrate on one side and HCl on the other side of the battery, and have been able to determine in this case the polarisation to be equal to 0°54 volt, which very nearly accounts for the difference between the E.M.F. of the open battery and the H.M.F. calculated according to Thomson’s theorem. The H.M.F. of PtH,NaClAq,PtO we found equal 0°86 volt, which, added to the polarisation of | 0:54 volt just mentioned, gives a total of 1°40 against the theoretical | figure for H, O = 1°47. By changing the gases after the polarisation was fully established, the battery showed an E.M.F. of 1°39 volts. This observation, as well as the determinations of Peirce,* of the H.M.F. of gas batteries with the same gases and different electrolytes, siows that the electrolyte also has considerable influence upon the | We hope by further investigation to arrive at assigning their | proper value to the various causes affecting the H.M.F. of gas batteries. VI. “Contributions to the Chemistry of Storage Batteries. No. 2.” By E. FRaNKLAND, D.C.L., F.R.S. Received June 18, 1889. Under this title 1 communicated to the Royal Society, in February, 1883,} the results of some experiments on the reactions occurring during the charging and discharging of a storage cell. I showed that no appreciable part of the storage effect was due to occluded gases, as had been previously suggested by some chemists and physicists; but that the act of charging consisted essentially in the decomposi- \ tion of lead sulphate whilst the discharge was produced by the re- composition of this salt. The establishment of these, as practically the only reactions going on ina storage cell, enabled me to prescribe a very simple method by which the charge in any cell could be ascertained; for as sulphuric | acid is liberated during the charging and absorbed by the active | material of the plates during discharge, the amount of charge could * ‘Wiedemann, Annalen,’ vol. 8, 1879, p. 98. t ‘ Proceedings of the Royal Society,’ vol. 35, p. 67. 1889.] the Chemistry of Storage Batterves. 305 at any time be measured by ascertaining the amount of free sulphuric acid in the cell; in other words, by simply determining the specific gravity of the electrolyte; and this method has since been very generally adopted by the users of storage batteries. In continuing these experiments, it soon became evident that the lead sulphate formed and decomposed in the cell could not be the ordinary white sulphate hitherto known to chemists, because, in the first place, the active material of the plates always remains coloured even after discharge, and secondly, because whenever white sulphate is produced through abnormal reactions in the cell, it is afterwards decomposed only with extreme difficulty by the electric current. In order to obtain some light upon the composition of the sulphate formed and decomposed in the cell, I have studied the action cf dilute sulphuric acid upon litharge and minium, the two oxides of lead chiefly used in the construction of the plates of storage cells. Action of Dilute Sulphuric Acid on Litharge. Finely powdered litharge was treated with successive portions of dilute sulphuric acid until the liquid remained strongly acid after prolonged trituration. The resulting insoluble buff-coloured powder was washed with water till free from acid, and dried, first at 100° C. and afterwards at 150—160°. The loss at this higher temperature was less than 0°2 per cent., and was therefore due to hygroscopic moisture. PbO and SO; were then determined in the dried compound as follows:—The salt was dissolved in a small quantity of pure con- centrated solution of caustic potash, and the solution, after dilution, was saturated with CO,. (According to H. Rose, COPbo” is soluble in COKo,, but not in COHoKo.) Any excess of CO,, which might have caused the COPbo” to dissolve, was avoided by warming the liquid with the precipitate on the water-bath to a temperature at which the COHoKo begins to dissociate. The liquid was then allowed to cool and to stand twelve hours before filtermg. The COPbo" was filtered off, converted into nitrate, and precipitated and weighed as sulphate. The sulphuric acid was determined in the filtrate from the COPbo”. 1:2964 grams of the salt gave 0°6647 gram baric sulphate and 14437 gram plumbic sulphate. : These numbers agree closely with the formula— (SO3)3(PbO);, as is seen from the following comparison of calculated and experi- mental numbers :— Te 2 306 Dr. E. Frankland. Contributions to [June 20, . Caleulated. ao—_—_*— Found Scipio a FAQ) avd ay bea a, ped Pu! a = ee 1115, 0482008 5 81-96 1355 100-00 | 99°57 These analytical results suggest the following graphic formula :— PbO, PbO, PbO, The formation of this salt may be represented by the following equation :— Litharge. Sulphuric Buff lead Water. acid. salt. Action of Dilute Sulphuric Acid on Minium. Minium was treated with dilute sulphuric acid in exactly the same way as litharge, and the resulting brownish red compound dried, first at 100° C., and afterwards at 150—160°. The loss at this higher temperature was again less than 0-2 per cent. PbO, SO., and excess of oxygen were then determined in this salt in the following manner:—The salt was first treated with concen- trated hydrochloric acid in order to reduce all the lead to the mon- oxide stage. The resulting mixture was then dissolved in caustic potash and treated as already described. The excess of oxygen was determined by finding the loss of weight which resulted trom the evolution of CO, when the salt was treated with oxalic acid and , dilute nitric acid. | 21136 grams of the salt gave 1:1978 grams baric sulphate and 2°2710 grams lead sulphate. 15110 gram treated with oxalic acid and dilute nitric acid evolved 0:0910 gram CQ,. These numbers correspond to the following od an — SO; ie ae 19°46 PhO! hotlines 79-08 CO 1-09 99:63 which agree with the forniula— S2PbsOio, 1889. | _the Chemistry of Storage Batteries. 307 as is seen from the following comparison :— Calculated. Found. aaa A ED Se Gene Sater Gey 7:78 Bi Meee. CON ESSF ee Le 73-41 O10 ae ar eee ae 160 ES Gai ice ern, 18°44 845 100-00 99°63 The composition of this salt may be represented graphically thus :— O | Pb : Ceram: | The formation of this salt is expressed by the following equation :— Pb,0,+280,H, = 8,Pb;0,)+20H). Minium. Sulphuric Red lead Water. acid. salt. These then are the salts which constitute the original active material of storage cells when that material is formed by the admixture of sulphuric acid with litharge or minium respectively, and it is highly probable that one or the other of these salts takes part in the elec- trolytic processes of the storage battery. It is fortunate that these hitherto unknown salts (and not the ordinary known sulphate) are formed in the cell reactions; for, in the alternative case, lead storage batteries would be practically valueless. If the buff lead salt be the active material of the battery plates, then the following equations express the electrolytic reactions taking place in the cell:— I. In charging— (a.) Positive Plates. S,Pb;0,,+ 30H, +0; = 5PbO, +380,H,. Buff lead Water. Lead = Sulphuric salt. peroxide.* acid. (b.) Negative Ptates. * Mr. Fitzgerald considers that this peroxide is hydrated. 308 The Chemistry of Storage Batteries. [June 20, II. In discharging— (a.) Positive Plates. 5PbO,+3S0,H,+5H, = 8,Pb;0,,+80H). (b.) Negative Plates. 5Pb+380,H,+ 0, = S3Pb;,0,,+30Ho». If the red lead salt be the active material, then the following equa- tions express the same electrolytic reactions :— I. In charging— | (a.) Positive Plates. Red lead Lead Sulphuric salt. peroxide. acid. (b.) Negative Plates. | S,Pb,0,)+4H, = 3Pb+2S80,H,+20H,. Il. In discharging— (a.) Positive Plates. (b.) Negative Plates. 3Pb+2S0,H,+ 20, = S,Pb30;,5+ 20H. An inspection of these equations discloses, in the case of the red lead salt, a fact which has already been roughly observed in practice, viz., that only half as much active material is electrolytically decom- posed on the negative as on the positive plates; whence it follows that the weight of active material on the negative plates need not exceed one-half of that upon the positive plates; for, in the decom- position of the electrolyte, equivalent quantities of oxygen and hydrogen are evolved ; that is to say, two atoms of hydrogen for each atom of oxygen. But, in the decomposition of the red lead salt, four times as many atoms of hydrogen are required to reduce the salt to metallic lead as atoms of oxygen which are necessary to transform the lead of the salt into peroxide. When, however, the active material of the positive plate has once been converted into peroxide of lead, it seems probable that the red salt only is formed; at all events until the discharge at high potential is nearly completed, when there are indications of the production of the buff-coloured salt. But this is a point requiring further investigation. I have to thank Dr. F. R. Japp, F.R.S., for his assistance in the analytical work of this investigation. 1889. ] Contributions to the Anatomy of Fishes. 309 VII. “ Contributions to the Anatomy of Fishes. I. The Atr- bladder and Weberian Ossicles in the Siluride.” By T. W. Bringe, M.A., Professor of Zoology in The Mason College, Birmingham, and A. C. Happon, M.A., Professor of Zoology in the Royal College of Science, Dublin. Com- municated by Professor A. NEWTON, F.R.S. Received June 12, 1889. Weber, in his classical memoir entitled ‘De Aure et Auditu Hominis et Animalium. Pars. 1—De Aure Animalium aquatilium,’ published in 1820, was the first to show that in certain families of Physostomous Teleostei, which were subsequently grouped together under the name of Ostariophysexe by the late Dr. Sagemehl, there exists a peculiar connexion between the membranous labyrinth of the internal ear and the air-bladder by means of a chain of movably interconnected ‘‘ auditory” ossicles. Of the four families (Gymnotide, Characinide, Gymnarchide, and Siluride) in which this singular mechanism is present, the Siluride have received but compara- tively scanty attention since the publication of Weber’s paper. Weber himself only described the air-bladder and auditory ossicles of one species (Silurus glanis). Johannes Miller, in his various com- munications to the Berlin Academy during the years 1843-45, added somewhat to our knowledge of these structures, and notably by his discovery of the springfederapparat; but Miiller’s attention was mainly directed to the grosser features in the anatomy of the air- bladder to the entire exclusion of all but the slightest reference to the important skeletal modifications which are associated with the peculiar structure of that organ in the Siluride. MReissner has given a fairly complete account of the bone-encapsuled air-bladder of Rhinelepis, but by far the most valuable of the more recent contribu- tions to this branch of vertebrate morphology are the papers by Professor Ramsay Wright, relating to the aberrant Siluroid Hypothalmus, and to the more normal North American species, Amiurus catus. In his papers on Amiurus, Professor Wright was not only the first to describe the fusion of the second, third, and fourth vertebree in the formation of what we have termed the ‘‘ complex vertebra ’’—a fact which could hardly have been discovered except through embryological evidence—but was also the first to give an accurate account of the skeletal relations and attachments of the air- bladder in any one Siluroid. In this preliminary communication we propose to state briefly the results of our investigations into the various modifications which the air-bladder and the ‘‘auditory ossicles” undergo in ninety-two OO Sno e » M4 * 310 Profs. T. W. Bridge and A. C. Haddon. [June 20, species of Siluride, referable to about fifty genera, and mainly belong- ing to Dr. Giinther’s sub-families of Siluridee Homaloptere, S. Heter- optere, S. Proteropterz, and S. Proteropodes. For the present we shall only give a brief résumé of the morphological variations in the structures concerned, leaving their physiological bearing and the more general conclusions which the facts elucidated suggest, to a future and more detailed communication to this Society; but before doing so we venture to suggest the need of a revision of the customary nomenclature of the so-called ‘auditory ossicles.” From a mistaken idea of their homology with the Mammalian au- ditory ossicles, Weber gave to three of them the suggestive but extremely misleading names of “incus,” ‘“‘ malleus,” and “stapes.” Since Weber’s time, however, it has become obvious that the “auditory ” ossicles of the Ostariophysez are in no sense homologous with the similarly named bones of the Mammalian tympanum, and it is almost equally clear that the two series of ossicles have nothing in common with regard to their respective functions. With a view of avoiding all possibility of the confusion which may result from applying identical terms to structures widely different in origin and. probably equally remote in function, we venture to suggest a different nomenclature for the ‘‘ auditory ossicles”” of Weber. Instead of stapes we propose the name “ scaphium,”’ in allusion to the invariably concavo-convex or spoon-shaped form of this ossicle. The “incus”’ may be renamed the “intercalarium,” from its constant intermediate position between the “stapes” and the ‘malleus,’ when present. For “‘ malleus” we would substitute “tripus”’—a name suggested by the three characteristic processes which this ossicle invariably possesses. The fourth ossicle, called the “claustrum” by Weber, forms one of the series of auditory ossicles in the Cyprinoid fishes, but has no such physiological significance in the Siluride, although it is very generally present. As the name “claustrum”’ is open to none of the objections which can reasonably be urged against the reten- tion of Weber’s nomenclature of the three preceding ossicles, it may with advantage be retained. For the ossicles collectively, including the claustrum, and for obvious reasons, we would suggest the name ‘‘ Weberian ossicles ” as an appropriate designation, instead of ‘* audi- tory ossicles.” In summarising the more noteworthy of the results of our investi- gations into the morphology of the air-bladder and Weberian ossicles, and the correlated modifications which the anterior vertebre and their processes undergo, we may indicate, in the first instance, such features as appear to be common to nearly all Siluroids, and secondly, those that are characteristic of particular genera or species. Although only demonstrated in one particular instance (the young of Amiurus catus) by Ramsay Wright, our researches lead us to 1889.) Contributions to the Anatomy of Fishes. 311 believe that the great majority of Siluroids agree with Amiurus in having the centrum of the second vertebra, and the centra, neural arches, and spinous processes of the third and fourth vertebre indistin- guishably combined to form an apparently single vertebra, for which we venture to suggest the name of “‘complex vertebra.” The dis- covery by Baudelot that the ‘‘ complex vertebra ”’ of the Cyprinide was formed by the fusion of the second vertebral centrum with the third vertebra, was due to the distinctness of these elements in one particular species, but no evidence of a similar nature is available in any but embryonic Siluridz. In no adult Siluroid is there the slightest trace of intervertebral spaces or sutures between the three confluent centra, in fact, the only features which in any way suggest the composite nature of the complex vertebra in that family are the perforation of its neural arch by two pairs of spinal nerves and the occasional pre- sence of two pairs of nutrient foramina on the ventral surface of its centrum. This fusion of vertebre in the formation of the “‘ complex” is almost invariably attended by the partial anchylosis of the latter to the fifth vertebra, partly as the result of the firm sutural union of their correlated elements, and in part due to the investment of the lateral surfaces of their centra by a continuous deposit of superficial bone. Moreover, the conjoined vertebre, with the addition of the centrum of the first, are so articulated to the skull that little, if any, motion is possible, either between the individual vertebra or between the latter and the skull. The centrum of the first vertebra is nearly always more or less rudimentary. With the possible exception of the claustra no distinct or ossified intercalary elements are ever present. The first vertebra very rarely has transverse processes, and even when present (e.g., some species of Arius) they are extremely rudi- mentary. The transverse processes of the fourth vertebra, on the contrary, are always greatly expanded, not infrequently divided into anterior and posterior division by a cleft, and with or without the aid of those belonging to the fifth vertebra form a more or less com- plete investment to the dorsal and anterior walls of the air-bladder. The sixth is, as a rule, the first rib-bearing vertebra; exceptionally, however, it may be the fifth (Callichrous), or even the seventh (Clarias). In almost all cases, except where they are modified to form an “ elastic-spring-apparatus,” the transverse processes of the fourth vertebra, in addition to their characteristic relations to the air-bladder, form a more or less rigid support to the proximal elements of the pectoral girdle. Over a somewhat triangular area, on each side, between the ex- occipital in front and the anterior margin of the arch of the complex vertebra behind, the wall of the neural canal is formed only by fibrous 312 Profs. T. W. Bridge and A. C. Haddon. [June 20, membrane, in which the claustrum and the ascending process of the scaphium are imbedded. Of the four Weberian ossicles the claustrum has no physiological relations to the atrial cavities (atria sinus wmparis of Weber), but merely strengthens the wali of the neural canal behind the exoccipital. Each scaphium has a spatulate process which fits into and completely closes the corresponding external atrial aperture, and at the same time forms the outer wall of the atrial cavity of its side, and alsoa rounded condylar process for articulation with the centrum of the first vertebra. The intercalarium is usually represented by an elongated or discoidal nodule imbedded in the stout ligament (‘‘interossicular ligament”) connecting the scaphium with the tripus, and even if horizontal and ascending processes are present, the ossicle never articulates with the centrum of the second vertebra to which, as a modified neural arch, it belongs. The tripus is always a tripartite ossicle with its posterior or crescentic process imbedded in the dorsal wall of the air-bladder; the anterior process is directed forwards parallel to the long axes of the complex and first centra, and opposite the external atrial aperture of its side 1s connected by the trans- versely-disposed interossicular ligament with the convex outer surface of the spatulate process of the scaphium. The articular process usually articulates with the lateral surface of the vertebral centrum (the third), of which it is a modified transverse process; very rarely (e.g., Auchenipterus) is the process directly continuous with the neural arch. The Weberian ossicles, or at all events the free portion of the tripus and the intercalarium, are enclosed within a membranous saccus paravertebralis, the anterior wall of which is perforated by the interossicular ligament as the latter passes forwards from the tripus to its attachment to the scaphium. Unlike the Cyprinide, the com- plete closure of the external atrial aperture by the spatulate process of the scaphium and the minute size of the hypoglossal foramen in the Siluride completely cut off all communication between the cavity of the saccus and the cranial cavity. The first spinal or hypoglossal nerve perforates the exoccipital. The second and third spinal nerves emerge from the neural canal between the claustrum anteriorly and the arch of the complex vertebra behind, but are invariably separated by the ascending process of the intercalarium whenever that process is developed, as in Macrones, Inocassis, and Bagroides. The fourth and fifth spinal nerves traverse the neural arch of the complex vertebra, and the sixth, the arch of the fifth vertebra. The additional spinal nerve described by Sagemehl in Silurus glanis as emerging between the clanstrum and the ascending process of the scaphium, we have never met with, although our attention has been specially directed to that point. ae oe py 1889. ] Contributions to the Anatomy of Fishes. 313 The air-bladder varies greatly in degree of development, not only in different genera, but in different species of the same genus. Hven individual variations are not infrequent. Very rarely does it exhibit the bipartite division into an anterior and a posterior sac so charac- teristic of other families of Ostariophysez. One of its most note- worthy features is a tendency to lateral development, whereby the outer walls of the anterior portion become applied, through the divergence of the dorso-lateral and ventro-lateral muscles of the body wall, directly to the external skin (‘‘ lateral cutaneous areas’’). The insertion of the crescentic processes of the tripodes is always into the dorsal wall of the anterior chamber of the air-bladder in the normal Siluride, or into the corresponding walls of the laterally situated air- sacs in the abnormal forms, and takes place in such a way that the fibres forming the anterior and lateral walls of each half of an anterior chamber, or of each air-sac, converge as they pass into and form the dorsal wall, and ultimately become inserted into the convex outer margin of the tripus of that side. Specialised fibres of the dorsal wall (‘‘radial fibres”) converge like the radii of a circle from the inner concave margin of the crescentic process, and are inserted either directly into the adjacent lateral surface of the complex centrum or indirectly through the intervention of an osseous nodule (“radial nodule’’). Hxcept, perhaps, in cases where the same effect is produced by their partial encapsulation by bone, the anterior chamber of the bladder, and its equivalent the laterally-situated air-sacs of the abnormal Siluride, generally have their walls so attached to, or buttressed by, rigid portions of the axial skeleton, that only their outer or lateral walls are capable by inward or outward bulging of allowing variations in the internal capacity of the bladder to take place. A ductus pneumaticus is very generally, but not invariably, present. | In nearly all Siluroids the lateral growth of the air-bladder, and the intimate relation of its outer walls to lateral cutaneous areas, have led to the displacement of the lateral lobes of the liver and their enclosure within peritoneal cul-de-sacs—a condition which usually persists even in cases where the air-bladder has undergone partial atrophy. In many of the features to which reference has just been made, the Siluride differ from all the other families in which a Weberian mechanism is present. As a convenient means of summarising the more important generic and specific variations, the Siluroids may be somewhat arbitrarily divided into two principal groups :—(1) the Stlwride normales, and (11) the Szluride abnormales. In the former group the air-bladder is always well developed and subdivided internally into three inter- 314 Profs. T. W. Bridge and A. C. Haddon. [June 20, communicating compartments, of which one is anterior and two pos- - terior or lateral in position. ‘The anterior and dorsal walls of the anterior chamber may be more or less completely invested by the modified transverse processes of the fourth and fifth vertebre, but the latter do not form deep concave recesses or capsules for the partial or complete enclosure of the entire air-bladder. In the Siluride abnormales on the contrary, the air-bladder is always small relatively to the size of the Fish, and more or less dege- nerate, sometimes partially solid, but almost invariably includes two laterally situated air-sacs with simple cavities, which together may be regarded as equivalent to the anterior chamber of a normal Siluroid. Lateral compartments, as a rule, are absent altogether, or, if present, are very rudimentary. Whatever its condition, the air- bladder is almost always partially or completely enclosed within transversely disposed bony recesses, formed either by the transverse processes of the fourth vertebra alone, or in conjunction with those of the fifth vertebra. Although a convenient method of classifying morphological facts, it is obvious that this classification, based as it is upon so variable an organ as the air-bladder, can have no genetic value. (1.) Siluride Normales. Under this head may be included such genera as :—Plotosus, Wallago, Callichrous, Cryptopterus (certain species). Eutropius, Pan- gasius, Macrones, Rita, Pimelodus (certain species), Piramutana, Arius, Osteogentosus, Oxydoras, Malapterurus, and others. In the Siluroids included in this group the number of rigidly inter- connected vertebrae varies. The first, the complex, and the fifth vertebre are almost invariably so connected together that no motion is possible between them, and occasionally the sixth, the seventh, and even the eighth may be included in the series. The rigidity of the complex and fifth vertebre, with the occasional addition of the sixth, may be further increased by the sutural union or partial anchylosis of their respective transverse processes. The anterior vertebre are also firmly connected to the skull, generally by the articulation of the arch and spine of the third vertebra with the exoccipitals and supraoccipital, the transverse processes of the fourth vertebra with the post-temporals, and the spinous processes of the third and fourth vertebrz with the supraoccipital spine ; less frequently by the forma- tion of interlocking accessory articular processes on the contiguous ventral margins of the basioccipital and the centra of the first and complex vertebre (Macrones, Bagrus). In Arius the accessory pro- cesses are very strongly developed, and by their downward growth and coalescence, form a stout, conical subvertebral process for the ee ae | 1889. ] Contributions to the Anatomy of Fishes. 315 attachment and support of the anterior wall of the air-bladder. In some Siluroids the connexion of the skull with the anterior vertebre may be rendered still more intimate by the articulation of the supra- occipital spine with the expanded dermal plates of the first and second interspinous bones, as in Auchenipterus, Oxydoras, &c., or even by the downward growth of paired processes from the supraoccipital to unite with the dorsal surfaces of the transverse processes of the fourth vertebra, as in Arius, Batrachocephalus, &ec. The centrum of the first vertebra varies greatly in size, but is always the smallest of the anterior vertebre. ‘Two pit-like sockets are always found on its dorsal surface for the reception of the globular condylar processes of the scaphia. The complex and fifth centra are the largest, or, at all events, the longest of the anterior vertebree, and, as a rule, their anterior and posterior concavities are unsymmetrically developed. In nearly all cases these centra are not only elongated but laterally compressed, so as to form a prominent subvertebral keel, which gives rise to a deep groove along the medio- dorsal line of the anterior chamber of the air-bladder, and, at the same time, internally, to a prominent longitudinal ridge, partially subdividing the cavity of the chamber into two laterally bulging halves. A fan-shaped subvertebral process may be developed from the ventral and anterior margin of the complex centrum for the support of the anterior wall of the bladder (e.g., Auchenaspis), and the lateral surface of the same centrum is not infrequently thickened into oblique lateral ridges for the dorsal attachment of the anterior pillars of the anterior chamber. For the same purpose a variously shaped osseous nodule (“radial nodule’) is attached to the dorsal extremity of each ridge, or in its absence directly to the centrum, and is either confluent therewith, or suturally, or by fibrous tissue only, connected thereto. The radial nodules in addition to serving for the attachment of the “anterior pillars’’ receive also the insertion of the radial fibres of the tripus. Almost invariably a thin slender lamina of bone, the ‘‘ radial ridge,” is prolonged from each radial nodule, and, after passing obliquely upwards, outwards, and hackwards, ventral to the posterior cardinal vein, blends with the ventral surface of the transverse process of the fourth vertebra. The neural arch of the complex vertebra is partially or completely anchylused to the arch of the fifth vertebra, which, in turn, may be similarly connected with the arch of the sixth vertebra, or the rigid union of the different neural arches may be effected by a firm sutural union. The transverse processes of the fourth vertebra, very frequently those of the fifth vertebra, and more rarely those belonging to the sixth vertebra (Platystoma), are more or less expanded, and by their partial ancbylosis or sutural union with one another, form on each. B16. -" Profs. T, W. Bridge and A. C. Haddon. [June 20, side of the vertebral column a broad, wing-like plate of bone, the anterior margin of which is strongly decurved, for the investment of the dorsal and anterior walls of the anterior chamber of the air- bladder. The transverse process of the fourth vertebra has a broad flat root, and may be simple, or, as is more usually the case, cleft more or less deeply into anterior and posterior divisions, of which the former is always decurved for a portion of its extent, and closely applied, even if not attached, to the lateral portion of the anterior wall of the bladder, in addition to its ligamentous or articular con- | nexion with the post-temporal. In certain Siluroids the transverse | process becomes modified to form the “ elastic-spring-apparatus,” first || described by Johannes Miller. In some of these forms (Malapterurus, Synodontis, Pangasius) each anterior division is almost completely separated from the posterior division, with an oblique origin from the arch of the complex vertebra, and, becoming flexible and | highly elastic, expands distally into a more or less oval plate, which HH is closely applied to the lateral portion of the anterior wall of the i bladder. In others (Auchenipterus, Oxydoras) the anterior division also forms an “‘ elastic-spring-apparatus,”’ but the posterior division is entirely wanting. In all such cases the modified transverse processes are provided with powerful protractor muscles, which have their origin on the posterior face of the skull, and their insertion into the anterior surfaces of the oval plates. The post-temporal bone always has a transversely, or obliquely, disposed inferior limb for articulation at its inner extremity with the lateral surface of the basioccipital, in addition to an ascending process | for articulation with the pterotic and epiotic bones. Where the trans- | verse process of the fourth vertebra fails to articulate with and | support the post-temporal, as is the case in all Siluroids possessing an | ‘ elastic-spring-apparatus,” the inferior limb of the latter is exception- ally massive, with an extensive articulation, or even partial anchy- losis, with the basioccipital or, in addition, with the exoccipital also. In other genera (Macrones, Bagrus, &c.) the inferior limb, in conjunc- | | tion with the body of the same bone, may form a bony expansion or | post-temporal plate, which, with the produced crescentic distal i extremity of the anterior division of the transverse process of the fourth vertebra, forms a slightly concave bony structure for the support of the lateral portion of the anterior wall of the bladder. From being but faintly concave on its posterior face, the post-temporal plate and the adjacent portion of the inferior limb may become deeply excavated to form a goblet-shaped cavity, into which a thin-walled ceecal diverticulum of the air-bladder extends (Macrones aor). Apart from those which are characteristic of all Siluroids, no important modifications of the hinder part of the skull are observable in the normal members of the group, either as regards the more 1889. | Contributions to the Anatomy of Fishes. 317 general features of structure or the more special points involved in the mode of formation and relations of the “cavum sinus imparis,” or of its bilobed backward prolongation, the “atria sinus imparis.”’ The uniformity in the latter respect is so marked, that a description of those structures as they occur in any one normal Siluroid will practically apply to all the others. . As regards the internal ear, the condition of many of our specimens was such that our observations were necessarily somewhat incomplete. The condition of the membranous labyrinth, and its relations to the cavum sinus imparis and to the atrial cavities, were investigated in a large number of Siluride normales but with the purely negative result that we could detect ne variations of any importance from the arrangement of these structures, already described for Amiwrus catus by Ramsay Wright, and for Siluwrus glanis by Weber. In all cases we found a transversely disposed ductus endolymphaticus connecting the two sacculi, and, attached to the ductus, a median pear-shaped sinus endolymphaticus projecting backwards into, and almost com- pletely filling, the “ cavum sinus imparis.” With the exception of the intercalarium, the Weberian ossicles exhibit but little variety in shape or in their relations to one another or to the atrial cavities and air-bladder. The variations in the condition of the tripus relate principally to the degree and shape of the curvature of its posterior or crescentic process. In some genera (Auchenipterus, Oxydoras) the crescentic process is almost straight ; in others almost hook-shaped (Plotosus) ; and between these extremes the process may exhibit almost every degree of curvature. A ventral ridge on the root of the crescentic process, to receive the insertion of a slip of fibres from the adjacent anterior wall of the bladder, is very generally present, and varies in size according to the thickness of the walls of the bladder. In some Siluroids (Macrones, Liocasis) the outer convex margin of the process may be increased for the purpose of fibrous attachment by the addition of an outwardly direcied heel- like process. The articular process of the tripus is usually distinct from the complex centrum, with which, however, it articulates at the bottom of a deep pit-like depression. It is very rare, as in one genus (Auchenipterus), for the process to be flexible and elastic, and directly continuous by an oblique origin with the anterior part of the neural arch of the complex vertebra like the adjacent and similarly elastic root of the “ elastic-spring-apparatus.” The proportional lengths of the anterior and crescentic processes vary somewhat in different forms ; generally, the two processes are of approximately equal length, but when otherwise it is the anterior which is the longer. The intercalarium varies greatly in development. Usually a small osseous nodule imbedded in the interossicular ligament, the inter- calarium may, in addition, be prolonged therefrom as a horizontal 318 Profs. T. W. Bridge and A.C. Haddon. [June 20, spicule which terminates in the fibrous wall of the neural canal, between the arch of the complex vertebra and the ascending process of the scaphium, near the dorso-lateral margin of the anterior portion of the complex centrum, with which, however, it is in no way directly attached (Cryptopterus, Callichrous). In a few genera (Macrones, Inocassis, Pseudobagrus, &c.) the horizontal process is prolonged upwards into a vertically disposed or ascending process, which also lies in the fibrous wall of the neural canal, behind and parallel to the ascending process of the scaphium. In all cases where an ascending process is present it les between the paired foramina for the exit of the dorsal and ventral roots of the second and third spinal nerves. The only variations noticed in condition of the scaphium relate to the occasional absence of an ascending process. Claustra are invariably present, but vary greatly in size, from the - condition of extremely slender spicules to somewhat triangular plates (Pangasius buchanani). The air-bladder has the same fundamental structure in all the S. normales. In all cases the organ is more or less cordate in shape, and is subdivided internally by a T-shaped arrangement of a primary transverse septum and a longitudinal septum into three intercom- municating compartments, of which one is anterior and transversely disposed, occupying the anterior third of the bladder, and two posterior or lateral longitudinally arranged chambers, constituting the posterior two-thirds of the bladder. The dorsal wall of the anterior chamber is closely moulded to the ventral and lateral surfaces of the complex and fifth centra, including the subvertebral keel which these centra form, and also to the ventral surfaces of the modified trans- verse processes of the fourth and fifth vertebre. The lateral portions of the anterior wall of the chamber are also partially buttressed by the decurved anterior margins of the transverse processes of the fourth vertebra, with or without the aid of the expanded inferior processes of the post-temporals (post-temporal plates), while the median portion of the wall is not infrequently supported by a sub- vertebral process (Arius). The lateral compartments, on the other hand, are neither invested by bone, nor are they in any way directly attached to the skeleton, but lie free in the abdominal cavity. Except in relation to the size of the Fish, the variations in the capacity of the anterior chamber as compared with those of the lateral compartments are but slight, and, as a rule, any increase or diminution in the relative size of the bladder is mainly due to variations in the size of the lateral chambers. With the exception of two genera (Rita and Aspredo) included in this group, the capacity of the anterior chamber is always much smaller than the combined capacities of the two lateral chambers, and, in one of the two exceptions referred to, the partial suppression of the lateral compartments is compensated by the 1889. ] Contributions to the Anatomy of Fishes. 319 development of two large lateral ceca from the anterior chamber. Apart from its partial longitudinal construction into two laterally bulging halves,—a separation which in some cases may be emphasised by the formation of one or two longitudinally arranged and inwardly projecting ridge-like aggregation of fibres from the median line of the posterior, ventral, and anterior walls,—the cavity of the anterior chamber has smooth walls, and is not subdivided by the growth of internal septa. The lateral compartments may also have undivided cavities (Auchenaspis, Callichrous, and Silurus), but not infrequently they are | rendered more inexpansible, and possibly at the same time less compressible, by the formation of a variable number of secondary transverse septa (e.g., Macrones), which incompletely subdivide each chamber into a series of transversely arranged, intercommunicating spaces. Occasionally the excessive development of these septa and their union by root-like bundles of fibres, which pass between their opposed surfaces, may lead to the formation of a thick trabecular network of fibrous columns or bands, and to the partial obliteration of the cavities of the two chambers (Pangasius). The width of the primary transverse septum forming the posterior -wall of the anterior chamber varies greatly in different Siluroids. In some (e.g., Auchenaspis) the septum is co-extensive with the width of the air-bladder, although contracted dorsally to admit of the lateral chambers communicating with the anterior chamber; in others (Callichrous, Cryptopterus) the septum is reduced to the condition of a narrow, but stout, column-like aggregation of fibres. Czecal appendages to the anterior and lateral compartments are not uncommon. The anterior chamber may have small anterior ceca (Macrones aor), or much smaller antero-lateral ceca (Osteogeniosus). Lateral ceca are sometimes present, and may either take the form of large funnel-shaped structures, which extend the whole length of the ‘abdominal cavity and are entirely free from internal subdivisions (Rita), or may otcur as small forwardly directed outgrowths, sub- divided internally by a network of fibrous bundles, and communicating with the anterior chamber by a number of slit-like orifices in its lateral walls (Platystoma). Very rarely (Callophysis) are the lateral ceca so numerous as to form a wreath round the lateral regions of the chamber. The lateral compartments are frequently either con- stricted or prolonged into a posterior cecal appendage. This may be a longer or shorter tubular, or a slightly oval structure, and confined to the abdominal cavity (Pangasius buchanant, Bagroides melanopterus), or a long, tapering, tubular structure, which, after traversing the abdomen, extends for some distance along the right side of the tail, between the hemal arches and the lateral musculature (Cryptopterus -micronema). In some cases the posterior cecum is very large, and in VOL. XLVI. : 2A wa 320 Profs. T. W. Bridge and A. C. Haddon. [June 20, shazse an elongated oval body (Pangasius djambal, Malapterurus electricus), or it may be flattened and leaf-like (Pangasius macronema). In one instance (Ozydoras) it is very rudimentary. The existence of a pair of rudimentary posterior ceca is very rare (Auchenapterus obscurus). Wery generally the longitudinal septum extends backwards into the posterior cecum, and subdivides its cavity into two distinct lateral canals or chambers, which communicate anteriorly with the proper lateral compartments of the bladder. Not infrequently the single or double cavity of the czecum is partially subdivided internally by a series of circularly disposed, inwardly projecting ridges (e.g., Malapterurus). In some Siluroids (Pangasius), where the lateral chambers are largely occupied by a trabecular network of fibrous bundles, the cavity of the posterior cecum is largely obliterated by the formation of a similar growth. It may be remarked that in nearly all the Siluroids with an “ elastic-spring-apparatus” that we have examined, posterior ceca were present, although in regard to their size and the extent to which their cavities are subdivided, or partially obliterated, cousiderable variety exists. In two species only (Auchenipterus nodosus and Pangasius micronema) are these structures entirely absent, In all the normal Siluroids, without an exception, a ductus pnen- maticus is present and opens into the anterior chamber in the median line of its ventral wall, and immediately in front of the ventral margin of the primary transverse septum. Not only is the anterior compartment of the air-bladder more or less completely invested by bone on its dorsal and anterior surfaces, but its walls are attached to rigid portions of the axial skeleton and to movable ossicles at certain special points. As to the nature and extent of the fixed skeletal attachments, there is substantial uni- formity in the different members of the group, and the physiological effect of such skeletal connexions is, in the great majority of cases, the same, viz., to render the anterior, dorsal, ventral, and posterior walls incapable of participating in any distension of the chamber, which, consequently, must solely depend upon the movements of the lateral walls. The posterior wall, 7.e., the primary transverse septum, is always attached by its dorsal margin to the ventral and lateral surfaces of either the complex or the fifth centrum—rarely to the sixth centrum ; laterally to this the dorsal edge of the septum is invariably attached to the ventral surfaces of the transverse processes of the fifth vertebra, or to those of the fourth vertebra, or exceptionally to the corresponding processes of the sixth vertebra; and, in addition, a sheet of fibres is generally prolonged forwards, on either side of the complex centrum, into the dorsal wall, where it eventually becomes attached to the radial ridge of its side. We propose to speak of these attachments as forming the “ posterior pillars” of the compartment. 1889.] Contributions to the Anatomy of Fishes. 321 As the anterior wall is usually more or less efficiently buttressed by the transverse processes of the fourth vertebra, or by post-temporal piates, or median subvertebral processes, the extent of its attachment - to the skeleton varies inversely with the extent to which it is invested or supported by bone. The median portion of the wall is always attached dorsally to the ventral.surface and sides of the anterior portion of the complex centrum, often by means of laterally situated, oblique, bony ridges, and also to the radial nodules. Laterally to this, on each side, the anterior wall may be so completely invested by bone as to be free from any special connexion or attachment to rigid portions of the axial skeleton (e.g., Macrones) ; or in correlation with a less complete bony support, the outer stratum of the tunica externa of the anterior wall may separate dorsally from the inner stratum and become firmly inserted into the decurved anterior margin of the transverse process of the fourth vertebra (e.g., Arius, Auchenaspis, Pimelodus). The dorsal attachment of the median portion of the anterior wall to the radial nodules and the complex centrum occurs in all the normal Siluroids, and may be regarded as constituting the “anterior pillars’ of the compartment. The ventral wall may aiso be considered as rigidly attached to the skeleton, both in front and behind, inasmuch as its inner stratum of longitudinally disposed fibres, some- times thickened into stout inwardly projecting ridges, extends into both the anterior and posterior walls, and shares the skeletal attach- ments of the anterior and posterior pillars. Although, as a rule, extremely thin, the median portion of the dorsal wall, over an area bounded in front and behind by the anterior and postevior pillars, and laterally by the dorsal walls of the two bulging halves of the chamber, is always firmly attached to the ventral and lateral surfaces of the complex centrum, and possibly also to those of the fifth centrum. The attachment of the walls of the anterior chamber to moveable ossicles (the tripodes) is effected by the convergence of the fibres of the anterior and lateral walls into the dorsal wall in the form of two triangular sheets, and their ultimate insertion into the crescentic ‘processes of the tripodes, which are situated near the anterior and inner corners of the lateral halves of the anterior chamber. The variations in the extent to which these fibres are attached to the tripodes are mainly confined to one feature. A slip of fibres derived from the median portion of the anterior wall is always inserted dorsally into the ventral ridge of each tripus, or directly into the ventral surface of the ossicle when the ridge fails to be developed. Laterally to this point the fibres forming the whole thickness of the tunica externa of the anterior and lateral walls may converge in the dorsal wall and become attached to the tripodes (e.g., Macrones); or as in many other Siluroids (e.g., Arius, Pimelodus, &c.) the outer stratum of the anterior wall is continuously attached by its dorsal 2a 2 i Pe Bis is 322 Profs. T. W. Bridge and A. C. Haddon. [June 20, edge to the transverse process of the fourth vertebra, and only the comparatively thin inner stratum, in addition to the fibres of both strata from the lateral walls, extend into the dorsal walls and consti- tute the triangular sheets. In the latter case but few, if any, of the fibres of the inner stratum reach the tripodes, which, in consequence, only receive the direct insertion of the outer stratum of the tunica externa of the lateral walls. Radial fibres arising from the radial nodules and inserted into the concave inner margins of the crescentic processes of the tripodes are invariably differentiated from the dorsal wall of the anterior chamber. in one instance (Auchenipterus), where the function of the radial fibres is taken by the flexible and highly elastic articular process of the tripus, the former are but scantily and feebly developed. As we have previously pointed ont, the lateral compartments of the air-bladder are neither invested by bone nor are they directly attached to the skeleton, but project freely into the anterior portion of the abdominal cavity. The most important feature in connexion with their structure, apart from their relatively greater capacity when compared with the anterior chamber, is their separation by a common longitudinal septum and the frequently septate condition of their cavities. Physiologically, the longitudinal septum and the secondary transverse septa subserve the double function of rendering the lateral chambers almost incapable of distension, and at the same time diminishing their susceptibility to the effects of external pressure. Although we have never been able to detect the presence of intrinsic muscular fibres in the walls of the air-bladder, powerful extrinsic muscles are present in several Siluroids. In Platystoma tigrinum, Pimelodus maculatus, P. ornatus, and Piraimutana piramuta, a powerful muscle takes origin from the posterior face of the skull, on each side of the foramen magnum, and is inserted into nearly the whole extent of the corresponding half of the ventral surface of the anterior chamber. As the contraction of these muscles must forcibly compress the anterior chamber we shall call them the ‘‘ compressor muscles” of the air-bladder. They probably occur in many other Pimelodine, but, so far as our investigations are concerned, are probably confined to that group. The presence of compressor muscles is invariably associated with the existence of a pair of much smaller muscles which arise from the exoccipitals, and are inserted into the anterior wall of the anterior chamber of the bladder. The tendon of each muscle has its insertion into the anterior wall immediately external to the complex centrum, and the insertion coincides with the extension of a slip of fibres from the inner surface of the anterior wall to the ventral ridge and concave inner margin of the erescentic process of the tripus. As the contrac- tion of these muscles must evidently have the effect of limiting the 1889. ] Contributions to the Anatomy of Fishes. 323 violent excursions of the tripodes which might otherwise take place when the anterior chamber is forcibly compressed by the contraction of its compressor muscles, we would suggest for each the name of “tensor tripodis.” An ‘elastic-spring-apparatus,” provided with powerful protractor muscles, has already been described by Johanues Miller as existing in the South American genera Auchenipterus, Doras, and Huanemus, and in the African Siluroids Synodontis and Malapterurus. To. this list our investigations enable us to add the South American form Ozxydoras brevis, and the Hast Indian species Pangasius buchanani, P. djambal, P. juaro, and P. macronema. The absence of this mechanism in one species of Pangasius, viz., P. micronema, while present in all the remaining species of the genus that came under our notice, is an interesting and noteworthy fact. In almost all normal Siluroids the lateral or outer walls of the anterior chamber of the air-bladder are more or less extensively and intimately applied to lateral cutaneous areas, and this relation of the two structures is always brought about by the divergence of the dorso-lateral and ventro-lateral muscles of the trunk, combined with the lateral extension of the anterior portion of the bladder. (II.) Siluride Abnormales. Omitting for the present all reference to such extremely aberrant forms as Hypothalmus, Rhinelepis, and the various Loricaroid Silurida, we confine our summary of this group to the various genera and species that have come directly under our notice. These are:— Clarias, Saccobranchus, Hutroptichthys, Cryptopterus (two species), Ailia, Schilbichthys, Silondia, Acrochordonichthys, Akysis, Pimelodus (two species), Bagarius, Glyptosternum, Amblyceps, Cetopsis, Calio- mystav. In all these forms the series of rigidly interconnected vertebra includes only the first, the complex, and the fifth vertebre, the sixth being almost invariably free. The rigid articulation of the anterior vertebree to the skull is as marked in this group as in the preceding one, and is brought about by precisely similar means. The centrum of the first vertebra is usually somewhat more rudimentary than in the normal forms, and neither it nor the basioccipital or the complex centrum are ever provided with accessory articular processes. The complex vertebra has the same general characters as in the foregoing group. Radial ridges and nodules are generally but are not invari- ably present ; exceptionally the radial ridge may have no connexion at its inner extremity with the complex centrum (Clarias, Glypto- sternum), and when this is the case the radial nodule may be absent, or confluent with the inner extremity of the radial ridge and widely separated from the complex centrum (Clarias). ol eee eee , = 324 Profs. T. W. Bridge and A. C. Haddon. [June 20, The most characteristic of the many skeletal modifications which are exhibited in this group is the formation of more or less complete ‘osseous grooves or funnels for the partial or complete enclosure of the air-bladder. Such recesses are formed by the transverse processes ‘of the fourth vertebra, either singly, or in conjunction with those of the fifth vertebra, and vary greatly in depth and in the extent to which they are surrounded by bone. They may be comparatively shallow and widely open on the ventral side, as in Akysis, Bagarius, and Gilyptosternum; or may take the form of deep, transversely - disposed grooves, contracted distally and somewhat expanded proxi- mally (Pimelodus sapo, Hutropiichthys, and Schilbichthys) ; or they may partake of the nature of transversely arranged bony cylinders or funnels, open distally in the dry skeleton, but otherwise with more or less complete osseous walls (Clarias, Callomystax, and Cetopsis). ‘The transverse processes of the fourth vertebra always form the dorsal and anterior walls of the recesses, and sometimes furnish, m addition, a posterior wall, or even incomplete ventral walls; rarely do they com- pletely enclose tubular recesses (Cetopsis); more frequently the ‘posterior walls are formed by the transverse process of the fifth ‘vertebra (Clarias, Callomystaz). Exceptionally, a slender, lateral, ‘bony outgrowth from each of the longitudinal ridges bounding the ‘aortic groove in the region of ‘the complex centrum may become attached to the ventral wall of the corresponding lateral air-sac ‘(Glyptosternum, Bagarius’)) ; or, as in one instance (Clarias), the out- srowths may be strongly developed and form no inconsiderable portion of the ventral walls of the two osseous funnels. Ventrally, ‘the shallow recesses may ‘be closed by a tough fibrous membrane which also invests the corresponding walls of the contained air-sacs (e.9., Bagarius); and by the same means vacuities in the walls of the more complete bony funnels are entirely closed (Clarias, Callomystaw). The formation of a horse-shee-shaped recess by the transverse processes of the fourth and fifth vertebrae in conjunction with plate-like lateral outgrowths from the aortic ridges, which is open laterally and behind in the dry skeleton, occurs only in one genus (Ailia). In whatever way the osseous recesses or capsules may be formed they are almost always open laterally or distally in the dry skeleton, and closed by lateral cutaneous areas in the fresh specimen. The condition of the air-bladder in this group is singularly varied, and in proportion to the bulk of the Fish is always extremely small. Many of its most characteristic features are clearly the results of atrophy and degeneration. The principal modifications appear to be due to the partial or complete suppression of the lateral chambers and the subdivision of the anterior chamber into two laterally situated cavities or air-sacs, either by the solidification of the mesial portion of the bladder or by more or less complete longitudinal constriction. : 1889.] Contributions to the Anatomy of Fishes. 325 In all cases the atrophied bladder is partially or completely enclosed within osseous recesses. In one or two instances (e.g., Schilbichthys and probably also Hutropiichthys) the air-bladder, although solid mesially, nevertheless retains in each half traces of its original and normal division into anterior and lateral compartments, but the ex- treme thickness of its walls, and the small size of its internal cavities, afford sufficient proof of its degenerate and functionless condition. Solidification of the central portion of the bladder may reduce the cavity of that organ to the condition of a circular canal of fairly uniform calibre, surrounding a massive central pillar (Silondia). Two species afford good examples of the extreme variability to which degenerate structures are liable. In one (Ailia), the bladder assumes the shape of a tubular horse-shoe, and is almost solid, except at its hollow forwardly curved cornua; in the other (Pimelodus sapo) the organ is solid mesially, and of its two pairs of forwardly curved lateral branches one only is hollow and receives the insertion of the tripodes. In one case (Cryptopterus micropus, and possibly also C. hevaptera) the bladder consists of two partially separated lateral sacs, but its degenerate character is betrayed by the partial obliteration of the cavity of the posterior half by a network of fibrous bundles. The more frequent condition of the air-bladder in this group is in the form of two simple, pyriform or globose, thin-walled, laterally placed air-sacs, which are either quite distinct or connected by an intermediate tubular portion (e.g., Glyptosternum, Cetopis, Acrochordon- ichthys, Bagarius, : m 2 a § é ¥ wt we ete DE i eee I eee oy 1889. ] ‘The Chemistry of the Urine of the Horse. 329 that, with the exception of the following references,* the literature of - the subject was remarkably bare. It is true that nothing had been done in England, but on the Continent, in Germany in particular, the urine of the horse has received especial consideration. My attention was later called to the following references.+ My difficulty at starting was to obtain the whole twenty-four hours’ urine; for this purpose I constructed a stall with sides which sloped towards the centre; running down the centre was a covered drain, the cover being perforated, and arranged in segments so as to allow of thorough cleaning; this drain led to the rear of the stall, and emptied into a vessel sunk in the ground suitably protected against ineress of foreign material. The entire apparatus was made in cast iron, and protected against rust. The arrangement was found to give absolute satisfaction. This plan of collecting the urine is nothing lke so complicated as that used by Munk and others in Germany, which consists of a bag into which the penis is placed, the bag being secured by numerous straps around the belly and between the thighs. There are very few English horses which would allow such an apparatus as Munk’s to be strapped under the belly. I shall use this appliance to collect the urine from sick animals, for it is likely that these will not object to wear Munk’s contrivance. . The horse to be experimented upon was previously weighed, when considered necessary, and was then placed in this stall and tied up for twenty-four hours; the stall was made very narrow.so that the anima! could not possibly shift from his position. To keep the feces _ out of the drain, a little clean straw was put down. One great object I had in view in making these experiments was to ascertain the difference between the urine of work and that of repose. The only way in which I could get approximate results with regard to the former was by working the animal for one or more days, and then collecting the urine for the last twenty-four hours; I always took the precaution of ascertaining in every case the urine of repose after at least two or three days’ rest. The total number of complete analyses made was fifty-four, and these extended over a period of two years; the total number of urines examined was ninety-six. Influence of season, work, diet, sex, age, &c., were most carefully observed. None of my results were * ¢ Animal Chemistry’ (Liebig) ; Thomson’s ‘ Animal Chemistry’ (Fourcroy and Vauquetin); Colin’s ‘ Physiologie Comparée’ (Boussingault) ; ‘ Phil. Trans.,’ 1806 (Brande) ; ‘ Physiological Chemistry’ (Lehmann) ; Simon’s ‘ Chemistry.’ + Salkowski, ‘ Zeitschrift fiir Physiologische Chemie,’ vol. 9, 1885; Munk, ‘ Archiy fir Anatomie und Physiologie, Physiol. Abth.,’ 1880, Suppl.-Heft; Tereg and Munk, 7bid.; O. Kellner, ‘ Landwirthschaftliche Jahrbiicher,’ vols. 8 and 9; Siedamgrotzky and Hoffmeister, ‘ Elémentsd’ Analyse Chimique;’ J. Tereg, ‘ Ency- klopidie der gesammten Thierheilkunde und Thierzucht’ (‘‘ Harn’’). 330 Prof. F. Smith. oY. [June 20; calculated until the inquiry was completed; it was then observed that the composition of healthy horse’s urine will vary within wide limits, and that even from day to day the same horse will excrete a fluid of very varying composition, though his condition of diet, &c., remains absolutely the same. J am not prepared at present to offer an ex- planation of this condition, which so seriously affects my tables of mean results as to render them only approximately true. Physical Characters of the Urine. Turbidity—The normal urine is invariably turbid, due to the suspension of the carbonates of lime and magnesia which precipitate themselves in still greater abundance as the urine cools and stands, and undergoes ammoniacal fermentation. The amount of salts in suspension is in some cases remarkable, the most common being the carbonates of ime and magnesia, which I have in the majority of my analyses estimated separately as sus- pended lime and magnesia. Boiling the urine by driving off CO, precipitates more of the lime salts. In one or two cases after the urine had stood some days, a hard scum, quite crystalline, has formed on its surface ; this has consisted of crystals of lime carbonate. Only once in ninety-six observations had I a perfectly clear urine presented for examination, a urine which threw down no deposit on cooling and standing, and was in most of its physical features closely allied to human urine. . Smell.—Perfectly fresh urine has a faint but distinctly ammoniacal smell; the fluid which represents the twenty-four hours’ excretion is always powerfully ammoniacal. This latter creates a difficulty with regard to the determination of urea, for it is impossible to say how much of the ammonia is due to changes in the urea, and how much is preformed ammonia. I have always felt this a trouble throughout the work, but will later explain how I have endeavoured to over- come it. . Reaction.—This is always alkaline, sometimes faintly, but in the majority of cases strongly so. The alkalinity shown by test papers is produced by a fixed and by a volatile substance—the volatile is the ammonia, the fixed is probably a salt of potash. It is obvious that the amount of volatile alkalinity present depends greatly upon the time of year, the condition of the urine (those containing most mucus containing most volatile alkalinity), and the length of time which has elapsed before the estimation is made. As remarked in the last paragraph, how much of the volatile alkalinity in urine twenty-four hours old is due to preformed ammonia, and how much to the ammonia formed at the expense of the urea, it is difficult to determine ; it is probable, however, that the preformed ammonia in urine is given 1889. ] The Chemistry of the Urine of the Horse. 331 off in twenty-four hours. Calculated as ammonia, the mean volatile alkalinity in twenty-four hours old urine amounts to 7:1016 grams for work and 7°8534 for rest ; these amounts I have added on to the urea, as | am convinced from long observation that they are formed from this substance. The fixed alkalinity expressed in terms of KHO gives a mean of 2:954 grams in urine twenty-four hours old, but in perfectly fresh urine it is equivalent to 4°8856 grams of KHO in twenty-four hours; this latter is probably too high. Consistence.—A large quantity of mucus in the urine is by no means an uncommon condition; this is particularly the case in mares, the urine being so thick and tenacious (more like linseed oil in con- sistence) that it takes some hours to get sufficient through the filter for analysis. The smaller the bulk of fluid excreted, the larger the amount of mucus it contains; it then becomes sticky and difficult to work with, still, it is a perfectly natural condition. In a urine of average con- sistence I have found 21°9 grams of mucus, and in one very tenacious 31°396 grams in twenty-four hours. Specific Gravity—The mean specific density is 1036, the highest recistered was 1050 and the lowest 1014. The formule of Trapp and Christison will not apply to the urine of the horse. Solids calculated by these give untrustworthy results. Quantity of Urine.—The mean amount of fluid excreted by working horses is 4474 c.c. and in animals that rest 4935 c.c. The largest amount produced in twenty-four hours was 11,300 c¢.c., and the smallest quantity secreted 2000 c.c. Neither season, sex, or age pro- duced any effect on the quantity of fluid secreted. In thirteen observations on the same horse, embracing both hot and cold weather, the largest quantities passed, amounting to over 10 litres, were produced during warm summer months. I place, however, no stress on this observation ; prokably in another series of experiments the results would be reversed. It is obvious that much of the bulk of fluid secreted will depend upon the quantity consumed. It is notorious that working horses are often stinted in their water. In one very careful experiment, where all the water was measured, it was found that more urine was excreted during the twenty-four hours subsequent to work than was excreted after absolute rest for one week. The water of the twenty- four hours’ urine equals + to 4 of the water drunk. Chemical Characters of the Urine. Total Solids —The mean amount of solids excreted by horses at rest was 230°0713 grams; of these the combustible solids are repre- sented by 146:1649 and the ash by 83:9064 grams. The total solids of 332 Prof. F. Smith. [June 20, work are 232°157 grams, the organic solids 152°190 grams, and the ~ ash 79°967 grams. Great variation both at rest and work is observed in the total solids, even where the diet remains the same. The nature of the diet, according to Tereg,* considerably influences the amount of the urinary solids excreted, as shown in the following table :— Daily ration. is Solids in the urine. Hay. Oats. Wheat ae grams. 8 kilos. 2 kilos. 566" 6 Toit, ot Qerel ooh availa: 529 “4 Me. ok 511°8 dees TT RR : 477 ‘0 BIG Ot TG. 460 °7 A egret yey eB 346 *1 About 90 per cent. of the ash is soluble in water, and 10 per cent. soluble in acid. In the watery solution of ash we find the chlorides of sodium and potassium, traces of lime, phosphates, magnesia, and sulphates. In the avid solution lime, magnesia, and sulphates pre- dominate. On looking at the inorganic solids, they are smaller than I had expected; the extreme difficulty experienced in incinerating urinary solids causes, undoubtedly, a loss by the volatilisation of the chlorides, &e. Urea.—In calculating the urea we have also to take into considera- tion the carbonate of ammonia which unavoidably forms during the twenty-four hours the urine is being collected. To show how much of the urea breaks up owing to fermentation, I have calculated it separately in the table, and then added the two together. I used Liebig’s method of determination for some time, but it gives too high results. My most trustworthy observations have been made with the hypo- bromite process. The influence of rest and work over the production has been most carefully studied. I originally held the view that more urea was excreted during work than during rest, and a long series of analyses supported this view. I found, in fact, in tabulating my results that the resting horses excreted on an average 88°41 grams of urea daily, of which 13:778 grams were in the form of ammonia carbonate; whilst working horses excreted 134°9291 grams, of which 12°4591 grams existed as ammonia carbonate. The incorrect conclusions which appeared forced on me were due to the fact that the excretion of urea, even ona fixed and rigid diet, is extremely variable, and in the horses from which the above results * “ Hneyklopidie der Gesammten Thierheilkunde,’ vol. 4. 1889. | The Chemistry of the Urine of the Horse. 333 were obtained I failed to keep any of them long enough under obser- vation to find out this point of variability. Again, diet influences the production, as proved by the work of Tereg, Munk, and others, who have shown that on a hay diet more nitrogen is excreted than on one containing oats as well as hay; this seems so opposed to what one would expect that I overlooked the point entirely. Tereg aud Munk put down the amount of urea as 120 grams ex- creted daily in a horse weighing 400 kilos., the diet being oats (4°5 kilos.) and hay (2°5 kilos.). The mean of my own observations is 111 grams; but urea varies much, even on a fixed diet, in different horses; in Tereg and Munk’s experiments it varied from 81'5 to 149°5 grams in twenty-four hours. _ 1 experimented on a pony weighing 5 cwt. 21 lbs.; the expert- ments lasted from 2nd February to 29th March, and were divided into periods of rest and work; the diet throughout remained the same, viz., hay 7 lbs., oats 5 ibs. . In the first series of rest and work I found that the animal excreted, on an average, for the resting days 63°63 grams urea, and for the working days 72:913 grams. In the second series of rest and work, all conditious remaining the same, I found more urea during the resting than-during the working period, viz., for rest 65°125 grams, and for work 43°33 grams. Urine of Rest. , Total nitrogen. Urea. 2nd Webruary ....-»-- 28 56 grams. 60 ‘0 grams. Ath NE nee Sor ahs .: OZR.” 6th Ash et PaO ee SALOU as 63,"4. The animal was now worked from the 7th until the 15th February, and again worked on the 17th and also on the 19th. Urine of Work. Total nitrogen. Urea. 6th Mebruary i...» 32°48 grams. 63 ‘0 grams. 18th See Tn uues pea AG be gs Sloe” .. 20th ree 6 a2 42°63 ,, 74°37 ,, Complete rest was now given until the 23rd February, when the experiments were repeated. Urine of Rest. Total nitrogen. Urea. 23rd February ....... 44°60 grams. 84: ‘0 grams. 26th ia: ek aan 2 SR oe BO OR WY & ipso Mere m. i's. P.. 3's Suro aaah os BeBe Ste see LO tne ei AO a, 334 Prof. F, Smith. [June 20, The animal was worked from the 14th until the 24th March, and again on the 26th and 28th March. Urine of Work. Total nitrogen. Urea. 25th March .......+. 16 324 grams. 30°25 grams. 27th ny CO eee eae Oo 7125s o2 “200% eon! | 28 eon. toby, 23-000 ,, 4750 yy The table clearly shows us how variable is the excretion of urea in spite of the fact that the diet remained the same; it is evident that the urea in horses is no more a measure of the muscular waste than itisin man. Kellner’s experiments* are remarkably complete. He made horses produce a definite amount of work; the experiment was divided into five periods :— Work produced. Nitrogen produced. Ist Period.... 475,000 kilogrammeters 99 ‘0 grams. 2nd) obra $2301 950,000 si 109. Sin SEG). «55-22 22 4o,000 53 L1G PB rans At) 59) oare)2'et fy 80j000 3 LEO G2 ees Sth ..-- 475,000 zs 98 53 eke 99 Here we have a slight increase in the output of nitrogen, quite insufficient to account for the increased work produced. Hippuric Acid—Owing to the statement made by Liebig that benzoic acid was found in the urine of working horses, and hip- puric in the urine of those which rested—a statement which has often been repeated since his time, and almost formulated into the doctrine that benzoic was present in the horses of the poor, whilst hippuric predominated in that of the wealthy—I have been at great pains to discover what element of truth the doctrine contained. The method employed for the determination of benzoic and hip- puric acids was the following :— The urine is treated with excess of milk of lime, filtered, evaporated to one-fifth of its bulk, and acidified with HCl. If hippuric acid be present it forms in some cases almost immediately, but in the majority it has to stand from twelve to twenty-four hours; if benzoic be present it forms almost at once. Both acids are in a highly impure condition, the hippuric (in black seaweed-like masses) is dissolved in water, boiled, and, whilst boiling, a current of chlorine gas passed through it to destroy the organic matter; it is then filtered hot, and deposits pure hippuric acid in fine needles in the course of a few hours. The impure benzoic is filtered, the solid residue collected in * ¢ Tandw. Jahrbiicher,’ 1879. 1889.] The Chemistry of the Urine of the Horse. 335 a capsule, dried at a low temperature, and carefully volatilised, when beautiful white sparkling crystals form, which are carefully removed, collected, and weighed ; or the impure mass may be dissolved in ether, the solution evaporated, and then volatilised. This volatilsation requires great care to avoid loss. I have tried many methods of obtaining these acids, but none give such satisfactory results as the above. The examination of the twenty-four hours’ urine of fifty-four horses revealed the presence of hippuric acid on only eight occasions. The number of horses at work was seventeen, and out of these I found hippuric acid twice, 2:144 grams and 18°6 grams respectively. The number of horses standing idle was thirty-seven; of this number I found hippuric acid six times; two of these observations I must deduct, as the horses were not in perfect health, leaving four out of thirty-five as the proportion in which hippuric acid was detected. Ina second series of observations consisting of thirty borses, the urine from which was collected and at once submitted to analysis, I found that out of eighteen working horses thirteen had hippuric acid in the urine and five had none. Out of twelve horses at rest three had hippuric acid and nine had none. The diet in all cases was the same. This would appear to reverse Liebig’s theory. My observations show that hippuric acid is generally found in the urine of working horses—seldom found in the urine of resting horses, and that it is rarely found in urine twenty-four hours old. Diet influences the production of hippuric acid, and it is increased by using meadow-hay and oat-straw, and decreased by using clover, peas, wheat, oats, &c.; as the urea rises the hippuric acid falls, and vice versa. (Tereg,* Weiske and Kellner.) The mean hippuric acid found was 15°58 grams, the maximum 28°56, and the minimum 9°18 grams in twenty-four hours. Salkowski places the hippuric acid at 15°597 grams daily. Benzoic Acid.—Benzoic acid is generally found in stale urine, and in the urine of horses which are doing no work. It may, however, be found in working horses, or a urine may possess neither hippuric or benzoic acids. The mean benzoic acid found in resting horses was 6°53 grams, in those at work 3°62 grams in twenty-four hours. Total Nitrogen.—In my earlier observations I believed that the nitrogen of work was greater than the nitrogen of rest. I have explained under urea how I fell into the error, and I have there fully detailed the nitrogen during rest and work in a series of experiments ona pony. The nitrogen is as variable as the urea; in my earlier series it varied for horses between 46 and 70 grams per diem. : * ‘Encyklopiidie,’ &e. + Watts’ ‘Dictionary of Chemistry,’ vol. 8, Part IT. VOL. XLVI, ra 336 Prof. F. Smith. [June 20, Here diet undoubtedly influenced its production—as previously pointed out under the head of urea. E. Salkowski states that a horse fed on 2 kilos. oats, 2 kilos. hay, and 1 kilo. bran, excreted 65°34 grams of total nitrogen in twenty- four hours. : According to Tereg and Munk, when horses are fed on rye instead | of hay and oats the nitrogen shows no change, but by feeding with peas the nitrogen increases, and that in proportion to the quantity given. If fed on hay alone the excreted nitrogen is very great, a fact as pointed out by these observers, which is very difficult of explana- tion. Ammonia.—This exists in the urine of horses free and combined ; the latter has been dealt with and its origin explained, the free ammonia may or may not be due to fermentation occurring in the bladder, but from a very large number of observations on perfectly healthy horses I affirm that ammonia exists in a free state in fresh urine. It may be that ammoniacal fermentation has already taken place in the bladder due to the quantity of mucus, and the long period during which the majority of horses retain their urine, due both to habit and circumstances, but it is quite certain that the perfectly fresh urine caught directly into clean vessels contains a distinct amount of ammonia. The amount of this ammonia cannot be estimated in urine twenty-four hours old, because it 1s impossible to distinguish if from the ammonia formed as the result of urea de- composition. The only way I have attempted to overcome the difficulty is by collecting perfectly fresh urine, and by Schlésing’s method determin- ing the ammonia before the slightest urea change, outside the body, has occurred. This process is far from being free from error, but is the least objectionable mode of procedure. I have previously stated that the ammonia found in urine twenty- four hours old may safely be calculated as urea, for that is un- doubtedly its origin. The preformed ammonia is probably completely given off before the twenty-four hours have ended. The amount of free ammonia in the urine of rest I have calculated at 2°516 grams, and in the urine of work 5°3 grams, but I do not regard these results as completely trustworthy. They nevertheless agree very closely, particularly that of work, with the ammonia obtained by the direct titration of fresh urine with a standard acid. Phosphoric Acid.—This acid is only found in comparatively small quantities in the urine of horses, the phosphates being principally eliminated by the bowels. 1889. ] The Chemistry of the Urine of the Horse. 337 According to Boussingault, horses do not excrete phosphoric acid ; this is not in accordance with our experience. Diet possesses no influence over its production, and the effect of rest and work is insignificant. I found that working horses excreted 1-897 grams as a mean, whilst horses at rest excreted 1:3 grams. Age has no influence over its production. ‘The largest amount found was 9°45 grams and the smallest 0°13 gram. The amount of P,O; will vary very considerably, many horses only just possessing traces of the acid, others distinct quantities. I am inclined to regard the mean amounts of phosphoric acid given above for rest and work as rather high. Sulphuric Acid and other Sulphur Compounds.—-Sulphur exists in two distinct forms in the urine of horses; the one I have calculated as SO,, the other, known as sulphur compounds, is calculated as S. - Diet appeared to have no influence in the production of SOs, work, on the other hand, increased it. Working horses excreted on an average 15°289 crams, and horses at rest 10°6468 grams in twenty-four hours. The SQ, appears to be increased in working horses in the same proportion as the urea. The sulphur compounds are said to exist in combination with phenol and other organic substances ; on this point I am not prepared to offer any opinion.* Work did not influence their production. Working horses yielded 76092 grams, horses at rest 7°3166 grams of sulphur. It is singular that horses should excrete so much sulphuric acid and other sulphur compounds. Chlorine.—More chlorine is excreted during rest than work, the mean amount for the former being 31°7119 grams, and for the latter 21:9806 grams in twenty-four hours. The chlorine is not affected by diet; it is united with potassium and sodium; the amount of the latter metal in the urine of the horse is small, and only yields with the chlorine about 53 grams of NaCl daily; the major part of the chlorine is united with potassium which is most abundant. * Some excellent work, has, however, been done in this direction by Salkowski, Tereg, and Munk. The latter observers state that on an average horses excrete 10°886 grams of tribromphenol in twenty-four hours, 10°175 grams of inorganic sulphur, and 5-039 grams organic sulphur in twenty-four hours. The tribrom- phenol is equivalent to 3 grams of phenol daily. Great importance is laid by these observers on the excretion of phenol, a process which is suspended during intestinal complaints, particularly colic, and is, according to them and others, a cause of the rapid death in these affections, produced by the toxic effect of the unexcreted phenol. The production of phenol in the healthy body is greatly influenced by diet, being largest on rye and hay, one part peas and two parts oats, and on hay alone; it is smallest on rye alone, and next smallest on oats and hay. Salkowski is inclined to regard ‘Tereg and Munk’s estimate of 3 grams of phenol daily as too high. 2 A Q “938 Prot. Es Smith: [June 20, Iime.—More lime exists in the urine of the horse than is soluble in an alkaline fluid, we have therefore lime both dissolved and merely suspended; these have been estimated separately. No direct connexion could be traced between the lime in the urine and the lime in the food, but between the production of lime and work a direct connexion appeared. The mean amount of dissolved CaO at work was found to be 1:9027 grams, and of the same salt at rest 34367 grams in twenty-four hours. Suspended Inme.— More suspended lime was found in the urine of horses at work than in those at rest, for the former 3°69 grams, and for the latter 11043 grams CaO. To state these points briefly, when horses work they excrete more lime in their urine than when at rest, but the lime of work is principally suspended, and only a part of it dissolved; whereas, the lime of rest is nearly all dissolved, and but little of it suspended. There is no connexion between the amount of mucus in the urine and the suspended lime. The largest amount of dissolved lime I found was 16°45 grams and the smallest 0°627 gram in twenty-four hours. The lime is found principally in conjunction with a carbonate, but I have also found sulphate and oxalate. The most common deposit in horse’s urine is the wheel-shaped crystals of hme carbonate. | On adding an acid to urine, extreme effervescence occurs as a rule, and the fluid is left quite clear like human urine; I have only on a few occasions witnessed any different results from these. The effervescence is usually extreme. Mugnesia.—-This, like the lime, exists partly in the suspended state and partly dissolved. Neither diet nor work have any influence over the production of magnesia. The soluble magnesia of work is 2°63 grams, and of rest 2°975 grams. The suspended magnesia of rest is 0°4218 gram, and of work 0°7925 gram. Potassiwm.—This metal is found largely in horse’s urine; it is principally combined with chlorine. Rest and work influence its production, there is more potash found in the urine of resting than in tlie urine of working horses. Working horses gave 27°06 grams whilst resting horses gave 36°59 grams in twenty-four hours. Sodium.—Is only found in small Prenat in the urine, the mean amount being 2°17 grams, and it is combined with chlorine, yielding a little over 53 grams of common salt for the twenty-four hours. The mean amount of sodium in working horses was 1°84 grams in twenty- four hours, in horses at rest it was larger, viz., 2°5 grams; yielding with chlorine less than 64 grams of common salt per diem. In some recent experiments, carried out on a pony, on the excretion of soda and potash during rest and work, the animal remaining under observation for several days, I found that the mean amount of | 1889. ] The Chemistry of the Urine of the Horse. 339 mixed chlorides excreted remained about the same, viz., 40 grams daily both at rest and work, but that during rest more potash and less soda was found than during work. This does not agree with the above experiments on the horse. I have compiled, from the mean result obtained, the following table of analyses of urine of healthy horses at work and rest. I observe that my inorganic solids of rest are in excess of the ash found, and moreover, that the amount of organic substances found in the urine of rest is much smaller than that obtained by evaporation and weighing. In both these matters the urine of work gives better results. It is obvious, however, that I have only dealt with the most com- mon and important substances found in urine; there are many organic substances which I have not looked for, or estimated, or have only estimated on so few occasions as not to entitle them to a place in the table. I do not for one moment intend it to be supposed that the table represents what all horses at work or rest excrete, for I have pre- viously stated that the horse’s urime is a fluid of very varying composi- tion; all the table represents is the mean of a large number of carefully made observations, which must be accepted as an approxi- mation to the truth rather than as absolutely trae. Table showing the Mean Composition of the twenty-fours’ Urine of Horses at Rest and Work. Rest. Work. EC. €.c. GUERIN Eb Cec cle ao HeaoenO einer 4935 44,74: DPC CHIC CLA MIGY. 65 aiken «10)i0 6 m0! s 6 1036 1036 grams. erams. MOtalSOhiGs, 4, pale sapelachdialots < vie cara 9 2OO [O83 232 °157 Oran BOWS vod na cess) de ei getsc | La0 1649 152 °190 nor Pamie SONGS ear. siete: «ye ae see 83 ‘9064 79 ‘967 Wise) 6 Sse antog oko Oar Ome AO Coulee 98 -5110 Ammonia carbonate as urea ....... 13°1185 PASM OUE A Perens) tela ele oekeielais ae eee se 2°516 5 *8000 PP CTUOMC ACTON Ed iaheraie one sys Se cues Wks 6 630 ¥ AEWA (MUETO RAGICL Siac jai a)/s Waiela a} >'efeieiiois = a 15 5870 Phosphoric anhydride ............ 1 3000 1 +8970 Sule emibyd rides.) .yepcetatels «ays 10 °6468 15 °2890 Other sulphur compounds......... 7 °3166 7 6902 Gnomes ees es ete lees bee 381 °7119 21-9806 Cileonmiromides). os Mates oe Lis aes 3 °4367 1 9027 {TR ta TMV ENTS AUG Cee ore Ae POO et 2 °9750 2 -6300 Polassuum OE Cece. «ase. 0 8070000 27 ‘0600 Bowman, Oxi eur lamest ds visser oc 2 °5000 1°8400 SS ee ee 340 - Dr. W. Marcet. A Chemical Inquiry [June 20, I have made no mention of the changes which occur in the urine as the result of disease, for the reason that I purpose devoting a special article to this subject, which is at present under investigation, though necessarily slow in progress, and far from being completed. It is singular to observe that any important derangement of the horse’s health is associated with an acid urine, the presence of uric acid and large phosphates, and the production of a clear human-like urine in appearance; this change is produced as soon as the animal refuses food and commences to live on its own tissues. [X. “A Chemical Inquiry into the Phenomena of Human Respiration.” By Winu1AmM MaArcet, M.D., F.R.S. Received June 3, 1889. (Abstract.) Before entering upon this communication, I must beg to acknow- ledge the valuable aid of my assistant, Mr. C. F. Townsend, F.C.8., to whose diligent, methodical, and careful work I am greatly indebted for the results obtained in the present research. The numerous calculations have all been made by both of us together, and the results checked in every possible way to insure accuracy. My attention was first turned to the chemical phenomena of respira- tion in 1875, and since then I have had the honour of communicating to the Royal Society a succession of papers on the “ Influence of Altitude on Respiration,” which have appeared in vols. 27, 28, 29, -and 31 of the ‘ Proceedings.’ These inquiries show in a most conclusive manner that altitude exerts an action on respiration depending entirely on the fall of atmospheric pressure. The law can be expressed as follows :—The volumes of air breathed, reduced to 0° C. and 760 mm., in order to yield the oxygen necessary for the production of a given weight (say, 1 gram) of carbonic acid, are smaller on mountains under diminished pressures than in the plains under higher pressures. My earliest experiments on the Breithorn, 4171 metres (13,685 feet) ; the Col St. Théodule, 3322 metres (10,599 feet); the Riffel, 2368 metres (8428 feet) ; St. Bernard, 2473 metres (8115 feet); and the Col du Géant, 3362 metres (11,030 feet), were all attended with a fall of temperature on reaching into higher altitudes. This cireum- stance necessarily produced an increased combustion in the body, to overcome the action of the cold, and introduced an element in the inquiry not unlikely to interfere with the exclusive influence altitude might exert on the chemical phenomena of respiration. In order to overcome the present difficulty I spent three weeks on the Peak of Teneriffe in the summer of 1878, where the 1889. | into the Phenomena of Human Respiration. 341 experiments were repeated. The temperature, though varying to a slight extent at different altitudes on the Peak, was always high in the daytime; hence there was no cause for any increased formation of carbonic acid in the body towards the resistance of cold. The result was most striking. While in the cold Swiss Alps I had observed an increased expiration of carbonic acid in ascending, on the Peak of Teneriffe there was no such effect produced. The mean weight of carbonic acid expired at the three stations, by two persons, was, with one exception only, applying to a Chamonix guide, the same for each of them respectively. But the volumes of air breathed at increasing altitudes were lessened,* so that the law remained unchanged—that at increasing altitudes, less air, reduced to 0° C. and 760 mm., is required to produce 1 gram of carbonic acid in the body. ‘The experiments on the Peak of Teneriffe, by doing away entirely with the influence of cold, place the fact beyond doubt. As it is important towards a clear understanding of the results contained in this paper that those obtained formerly should be present to the reader, I beg to subjoin them in a tabular form. Experiments on the Alps. (On myselt.) Litres of air expired for 1 gram COs, reduced to 0° and Station. Altitude. 760 mm. INearGeneVa ws... . t= a sro mm: (le 2a0 tty) > jo. oO SH enrrariln 2. 8 ck cs 2473 ,, (8,110 oa) ee eee: 2 ‘ above 8, ‘ aL eae Ua LE RO (Ey ee, S Livaal VEO BT (eget ae sone. (l0.o09 -.) 11:05 Summit of Breithorn.... 4171 ,, (18,680 ,, ) On the Peak of Teneritfe. (On myself.) SESSIONS RR Ge oe SN ie SIR IN ais Cae a RMN, falit MDN Btg 12°4 CWealaray feet eee hos 2 eS Abollm. “C2090 eae. el Pe VISta, ils eee bs be S201. CO 700n Saw LOre Foot of terminal cone.... 3578 ,, (11,740 ,,).... 10°6 On the Col du Géant. (On myself.) Near Geneva. . 6s.< 03h a¢o mi, C250 fh). <6 2.0 15% * An exception again for the Chamonix guide at his highest station, although the mean reduced volume of air he expired at the two high stations on the Peak is lower than that he expired at the seaside by 18 per cent. 342 Dr. W. Marcet. A Chemical Inquiry | | [June 20, Litres of air expired for 1 gram CO,, reduced to 0° and 760 mm. Mean before and after ascent. Courmayeuty ere see ire 1202 m. . (3,945 it.) cues Summit Col du Géant ... 3362 ,, (11,030 5.) 2a On M. David, aged 25. Wear (Geneva ier oct inte 3/5 m... (1,230 ft.) 2. eee Mean before and after ascent. Courmiayeux ¢.iaiehor ie. 21: 1202; 3, (3,945 flopper 148* Summit Col du Géant .. 3362 ,, (11,080 ,,) 252 220 The experiments were made by determining as carefully as possible the volume of air expired within a given time, and then estimating the amount of carbonic acid it contained by means of Pettenkofer’s method. The volume of air, reduced to 0° C. and 760 mm. pressure, holding 1 gram of carbonic acid, was then easily calculated. These experiments were subsequently repeated in 1882 on the Rigi Mountain in Switzerland, altitude 1594 metres (5230 feet), and as the results obtained have never been published, beyond a short reference to them in a communication to the Alpine Club, they are included in the present paper. My companion, Mr. Thury, a young engineer, aged twenty-five, submitted to the inquiry. Fifteen experiments were made near Geneva at a mean barometer pressure of (28 mm., and a mean temperature of 15°9° C., and eighteen as soon afterwards as possible on the Rigi Staffel, at a mean pressure of 639 mm., and a mean temperature of 76° C. As might have been expected, more CO, was exhaled in a given time on the cold mountain station than in the Valley of Geneva, a mean of 0°350 gram being expired near Geneva and 0°445 gram at the higher station, giving an excess of no less than 21 per cent. of carbonic acid for the Rigi. The amount of air expired—say breathed—for the expiration of 1 gram CQ,, reduced to 0° and 760 mm., was 10°78 litres in the Valley and only 9°45 on the Rigi. Therefore, for a mean difference of 89 mm. of atmospheric pressure, and with a marked fall of tem- perature, less air by 12 per cent. was breathed on the mountain to supply the oxygen required by the body to burn the same amount of carbon as in the valley. The present investigation has been carried out in a laboratory of the Physiological Department at University College, which Professor Schafer has kindly placed at my disposal. Its object was to ascertain * This is an exceptional case, owing clearly to the small increase of altitude between Geneva and Courmayeur, which only amounts to 827 metres. 1889.] into the Phenomena of Human Respiration. 1 343 the influence of food and changes of atmospheric pressure on the volume of air breathed and weight of CO, expired. ‘T'wo persons, my assistant, Mr. C. F. Townsend, and my laboratory attendant, William Alderwood, kindly submitted to experiment. The person under experiment sat in a semi-recumbent posture in a deck-chair, with his feet resting on a stool, so as to do away with all muscular effort. He inspired by the nose only, and expired through the mouth into a wide india-rubber tube, connected with a bell-jar, of a capacity of over 40 litres, and suspended over salt water. The bell-jar was accurately counterpoised over a pulley fixed to a cycloid, whose leverage power, increasing as the bell-jar rose, kept the latter perfectly balanced, ‘and therefore the air it contained was under atmospheric pressure in every position. The time for collecting the air expired was measured with a stop watch. In order to make sure of no air being expired accidentally through the nose, at the end of each inspiration the nose was closed with the index-fingers, and thus held during the expiration. In order to obviate the objection that the attention given to the experiment might interfere with natural breathing, the air was expired into the bell-jar through a double-way cock, disposed in such a manner that the person under experiment might, unknown to him, either expire into the external air or into the bell-jar. At the com- mencement of the experiment he was made to expire into the open air, and when, after ten minutes or a quarter of an hour, his respira- tion had become perfectly regular, the stopcock was turned and the air admitted into the bell-jar. The latter was so well suspended that it rose without the least effort; thus, the person experimented upon, unless looking at the bell-jar, could not tell whether he was breathing into it or into the external air. The carbonic acid was determined by aspiring with a pump the air from the bell-jar into a glass cylinder of a capacity of 1000 c.c., to which was subsequently screwed, air-tight, a bottle holding 100 c.c. of a normal solution of barium hydrate. After agitating the air with the akaline solution for a minute or two, about 100 c.c. of common air free from CO;, and contained in a pear-shaped india-rubber bag, was forced into the cylinder by pressure with the hand, and then the shaking resumed for a quarter of an hour. The addition of the air caused a pressure inside the cylinder which was found to accelerate greatly the combination of the CO,. Finally, the alkaline solution was decanted into a glass-stoppered bottle of a capacity of about 100 c.c., and the stopper secured with paraffin. The morning of the next day, when the precipitate had entirely subsided, the clear fluid was titrated with a standard solution of oxalic acid in the usual way. A number of precautions were taken to insure the accuracy of the method; perhaps the most important was blowing, with a bellows, a 344 Chemical Phenomena of Human Respiration. [June 20, current of air over pumice-stone moistened with a solution of potas- sium hydrate, through the wide mouth bottle in which the titration was being made; by this means no atmospheric carbonic acid could interfere with the correctness of the result. Fourteen pairs of analyses, made to test the method, gave a mean difference of only 0°31 per cent. Two comparative experiments were carried out in a large air-tight chamber in which a person lying in a deck-chair breathed first into an india-rubber bag, representing the bell-jar, and next into the air of the chamber. The air in the bag and in the chamber being subse- quently analysed yielded practically the same weight of carbonic acid expired within the same time.* The results obtained from the present inquiry are as follows :— 1. The law of nature is further demonstrated that less air, reduced to 0° C. and 760 mm. pressure, is breathed at high than at low altitudes for the formation in the body of a given weight of carbonic acid. 2. The known usual influence of food on the formation of carbonic acid in the body is confirmed—the maximum amount expired occur- ring between two and three hours after a meal, while the minimum is before breakfast. 3. The influence of food on the relation between the volumes of air breathed (reduced) and the corresponding weights of carbonic acid expired is clearly shown; the volumes following, as a rule, the fluctua- tions of the carbonic acid, but there is apparently a sudden change in this relation at a period of between four and five hours after a meal, when the carbonic acid expired falls proportionally faster than the volumes of air breathed. The harmony of the tracings in one of the charts accompanying my paper has recovered itself, however, over- night, and the lines are again nearly parallel before the first morning meal. In the other chart there are no experiments recorded made before breakfast. 4. The local state of the atmospheric pressure, as shown by the barometer, has a marked influence on respiration, less air, reduced to 0° C. and 760 mm. pressure, being taken into the lungs for the formation - and emission of a given weight of carbonic acid under lower atmospheric pressures than under higher pressures; but this influence varies in degree according to different persons. In the present inquiry when two young men were experimented upon—in one case, for a fall of pressure of 10 mm. (0°395 inch), there was a mean reduction of 1:076 per cent. of the volume of air breathed for 1 gram CO, expired; in the other case, the mean reduction was greater, and amounted to 1-745 per cent. 5. The above influence of local atmospheric pressures on the volume of air breathed is not the same throughout the whole day, being much less marked from two to four hours after a meal when the action of * In one experiment the difference amounted to 2°97 per cent.; in the other to 0°6 per cent. only. 1889.| Ona pure Fermentation of Mannite and Glycerin. 345 foodis atits maximum. Thus digestion neutralises in a great measure the effects on respiration of any local change of pressure, Two persons, both aged twenty-three, were found in the experi- ments related in this paper to require respectively a mean of 9°29 and 10°51 litres of air, reduced, to expire 1 gram carbonic acid. Hxperiments on another person, aged sixty, gave a mean of 11°30 litres of air; and with a number of others the propor- tion of air breathed for a given weight of carbonic acid expired also varied, showing that different individuals breathe different volumes of air to supply their body with the necessary amount of oxygen to make and expire a given weight of carbonic acid. It cannot be doubted that the less the volume of air inspired to burn a certain weight of carbon, the more readily the oxygen taken into the lungs finds its way into the blood, and, therefore, the more perfect the respiratory function. This may have important bearings in medical respects. The age of sixty years apparently necessitated breathing a comparatively large proportion of air (11°30 litres) to supply the blood with the oxygen it required. One of the two young men was physically stronger and possessed of a greater muscular development than the other, he breathed 9°29 litres against 10°51 for the other, or took 11°6 per cent. less air into his lungs to yield the necessary oxygen to burn the same weight of carbon within a given time. The corre- sponding difference between the person aged sixty, and the strongest of the two young men amounted to no less than 17°8 per cent. X. “On a Pure Fermentation of Mannite and Glycerin.” By Prercy F. FRANKLAND, Ph.D., B.Sc. (Lond.), Assoc. Roy. Sch. of Mines, Professor of Chemistry in University College, Dundee, and JosePH J. Fox. Communicated by Professor T. EK. THorps, F.R.S. Received June 17, 1889. Although the fermentative action of micro-organisms has from time to time attracted the attention of numerous investigators, both chemical and biological, still in by far the majority of cases there has been absolutely no guarantee that the chemical changes observed were the result of the activity of a pure growth of one organism and not of a more or less complex mixture of organisms. Indeed, it is only within recent years that the most familiar of all fermentations— the alcoholic—has been induced with growths of yeast definitely ascertained to be of absolute purity. Thus whilst Pasteur and others had many years previously studied the fermentation of sugar induced by yeast, free from bacteria and other micro-organisms, it is to Hansen that we owe the systematic investigation of the fermentations caused by distinct kinds of yeast in a state of unquestionable purity. 346 Dr. P. F. Frankland and Mr. J. J. Fox. [June 20, The greatly improved methods of isolating and studying micro- organisms, which we now have at our command, necessitate that all experiments on the chemical changes induced by micro-organisms, should in future be carried out with cultivations of guaranteed purity, as only under such conditions can the particular reactions be referred to the agency of particular organisms. It is, moreover, essen- tial that the micro-organisms themselves should be so fully described and characterised as to render possible their identification by other investigators, a point which has been but little attended to in the past. Thas the value of the classical work of the late Albert Fitz on schizomycetic fermentations is not a little diminished by the doubt which attaches to the purity of his cultivation, and to the inadequate description of the micro-organisms he had under observation. On the other hand, of course, these objections in no way detract from the importance of Vitz’s work in demonstrating that particular chemical changes can be effected by the agency of bacterial life. The present paper deals with some of the chemical changes pro- duced by a micro-organism which was obtained in a state of perfect purity by one of us from sheep-dung, which was found to have the power of setting up fermentation in suitable solutions of several carbohydrates and polyhydric alcohols. Isolation and Morphological Characters of the Fermenting Organism (by Grace C. FRanxianp and Percy F. FRANKLAND). A minute quantity of sheep-dung was introduced into test-tubes containing a sterile solution of glucose (3 per cent.) and the necessary mineral ingredients, together with a small quantity of peptone. On placing these tubes in the incubator at 39° C. they were found to be in a state of fermentation on the following day. A minute quantity of this fermenting liquid was transferred by means of a sterile platinum needle into other tubes containing sterile glucose-solution, and in these a similar fermentation was established. A number of further generations were produced by successive transferences in the same way, with the result that in each case a vigorous fermentation was set up. Some of the fermenting liquid from one of these tubes was then submitted to plate-cultivation with gelatine-peptone in the ordinary way. On the appearance of centres of growth on these plates, inoculations were made from a number of the colonies into tubes containing glucose-solution. On subsequently incubating these tubes some entered into vigorous fermentation, and from one of these a number of inoculations were made into tubes containing glucose, mannite, glycerin, and other solutions to which reference will be made later. The inoculated glucose, mannite, and glycerin tubes all entered into fermentation on being placed in the incubator. 1889.] Ona pure Fermentation of Mannite and Glycerin. 347 Plates were again poured from a number of these fermenting solu- tions of various ages, the resulting colonies were carefully examined and again inoculated into the fermentable liquids, and it was only when the purity and uniform character of the organism had thus been fully established that the larger quantities of fermentable material to be chemically examined afterwards were finally inoculated as described below. ‘ Microscopie Appearances—Under high powers (x 1000 x 1500) the organism is seen to be a bacillus with rounded ends, occurring chiefly in pairs, the individual bacilli vary in length from 1‘ to 51 », and in breadth from 0'8utol'O mu. Their appearance, however, as is so frequently the case, varies considerably, according to the medium from which they are taken. Thus in the fermenting liquids they were often found to form long threads, whilst in gelatine and other solid media they were usually found in pairs only. The accompanying figures, Nos. 1 and 2, illustrate the differences in the appearance of the bacilli when taken from gelatine and mannite-solution respectively. Erie. 1. Hie. 2. Pee ea, } & ~T / a ee | yee That this difference in appearance was not accidental but a constant character of the organism was demonstrated by inoculating gelatine- tubes from single colonies of the organism; on microscopically ex- amining the growths in these tubes, the characteristic short bacilli were found, but no threads; on inoculating, however, a series of glucose-tubes from these gelatine cultivations, the long threads were invariably found. Viewed in drop-cultivations, the bacilli were seen to be extremely motile. Appearance in Gelatine-Tubes—The growth is but little charac- teristic ; in the depth the needle-track assumes a beaded appearance, whilst the smooth surface-growth causes more or less rapid liquefac- tion of the gelatine, according to the temperature and according to the vitality of the organism; thus at low temperatures or when the organism has been inoculated from an old and exhausted previous growth, the liquefaction is very slow. Appearance in Agar-Agar.—The organism forms an extremely thin and almost invisible growth over the surface, which becomes hardly more conspicuous even when incubated for some time. 348 Dr. P. F. Frankland and Mr. J. J. Fox. [June 20, Appearance on Potatoes.—Forms a dirty-white, shining growth which extends over almost the whole surface of the potato. Appearance in Clelatine-Plate Cultivaiions——To the naked eye the colonies are very insignificant, appearing as small white dots; later on when liquefaction commences, clear liquid circles form round the small centres, the circles gradually increase in diameter until the whole plate may become involved. Under a low power (xX 100} the depth-colonies in which neither softening nor liquefaction of the gelatine has commenced, are seen to be smooth-rimmed disks with finely granular contents (see fig. 3), whilst those around which liquefaction has taken place exhibit a dark central mass surrounded by very finely granular matter, the periphery having a delicate hair-like appearance (see fig. 4). The same dif- ferences in the rate of liquefaction are observable as in the case of the gelatine-tube cultivations referred to above. Jn none of the cultivations were any spores discoverable. Fie. 3. Fia. 4. NN jail aN ANS ANIA > Sa2 =e = =: FERMENTATION OF MANNITOL. The fermentations were carried out in flasks of about 24 litres capacity; the mannitol was employed in a 3 per cent. solution, 2000 c.c. of solution being placed in each flask. The solution was prepared as follows :— 60 grams of pure mannitol, 2 grams of dry peptone, and 30 grams of precipitated calcium carbonate were placed in the large flask; 200 c.c. of a salt solution™ containing the necessary mineral ingre- dients for the growth of micro-organisms, were diluted to 2000 c.c. with distilled water and then added to the flask containing the mannitol, &e. 'The flask was then furnished with a plug of sterile cotton-wool, and the whole steam-sterilised for upwards of one hour on three to four successive days. * This salt solution contained— Potassium phosphate.............. 5°00 grams ) dissolved in Magnesium sulphate (cryst.)........ 1°00 ,, soo c.c. of Calcium chloride (fused) .......... 0°50 ,, water. 1889.] Ona pure Fermentation of Mannite and Glycerin. b49 The sterile liquid thus obtained was then carefully inoculated with a minute quantity of a pure culture of the organism and placed in an incubator, the temperature of which was maintained at 58—40° C. The fermentation commences in the course of a few days and con- tinues for several weeks. Three separate fermentations of mannitol were thus carried on. In each case, before commencing the chemical examination of the products, the contents of the flask were submitted to microscopic examination and to plate-cultivation with gelatine-peptone; in each ease the growth was found to have remained pure, only the charac- teristic colonies of the organism itself making their appearance on the plates. Fermentation of Mannitol No. 1. Two litres of mannitol solution, prepared as above described, were duly sterilised and then carefully inoculated with a minute trace of a pure cultivation of the organism. The liquid was then placed in an incubator the temperature of which was maintained at 38—40° C, The fermentation commenced on the third day and continued with more or less activity for about one month, but the liquid re- mained in the incubator for upwards of three months; at the close of this period it was submitted to plate-cultivation as above indicated, and the chemical examination then proceeded with. Separation of Alcohols—The fermented liquid, which still contained a quantity of undecomposed carbonate of lime, was distilled down to about one-third of its bulk and until the distillate gave only the faintest indications with Lieben’s highly sensitive iodoform reaction for alcohol. The residue in the distilling Hask was set aside to be examined for acids (see below), whilst the distillate, which would contain any alcohols, was redistilled over and over again so as to get rid of the greater part of the water. When the volume of liquid amounted to only about 50 c.c. a careful determination of the specific gravity was made, and this indicated the presence of 11°415 grams of absolute alcohol. Finally the liquid was dehydrated with fused carbonate of potash, and on then distilling it passed over at 79—80° C., showing it to be pure ethyl alcohol. Separation of Volatile Acids—The residue remaining in the flask, after distilling off the alcohol as above, would contain any acids in the condition of calcium salts; in order to liberate these acids a calculated quantity of hydrochloric acid was added, sufficient exactly to decompose the carbonate of lime originally added to the liquid. On then repeatedly distilling with water the volatile acids passed over and were converted into barium salts for analysis. The hydrochloric acid was not, however, added all at once, but in several distinct portions, and after each addition the liquid was 350 Dr. P. F. Frankland and Mr, J. J.Fox. - [June 20, severally treated with an excess of pure barium carbonate, boiled for one hour to expel carbonic anhydride, and then filtered; the filtrate containing the barium salt of the volatile acid was then evaporated and weighed after drying until constant at 130° C. » L104 grams 0-027 |,, Glycerol Fermentations. Alcohol. Acetic acid, Formic acid. Succinic acid. I,. [490] grams [2°75] grams [0°32 gram] 0:079 gram ee Slt BiG, du 9s trace ORO * Total volatile acid calculated as acetic acid. ova a | 356 Pure Fermentation of Mannite and Glycerin. [June 20, Remarks. (1.) Both mannitol and glycerol are fermented by this organism, with production of essentially the same substances, viz., ethyl alcohol and acetic acid, together with smaller quantities of formic and suc- cinic acids. The proportion of formic acid in both fermentations appears to be formed at the expense of the acetic acid, masmuch as in all cases the amount of acetic acid found varied inversely as the proportion of formic acid. The proportion of succinic acid, although in both cases very small, was distinctly greater in the glycerol than in the mannitol fermentations. (2.) The proportion of alcohol to acetic acid in the mannitol fer- mentations is constant, viz., as 1°63: 1, which corresponds to the molecular proportions. 20,H,-OH : CHyCOOH = 1:53 (2x 46) (60) (3.) Excluding the first glycerol fermentation, in which the alcohol found was doubtless too small, the proportion of alcohol to acetic acid is as 2°11 : 1, corresponding to the molecular proportions, 3C,H,-OH : CH,COOH = 2:30 (3 x 46) (60) (4.) In all the fermentations the decomposition was only an incom- plete one, a considerable part of the mannitol, and especially of the glycerol, being in each case recoverable after the fermentation was finished. We propose subsequently to investigate the cause of this limitation. (5.) In the mannitol fermentation it is impossible to determine whether the succinic acid is formed by a process of synthesis or analysis, but in the fermentation of glycerol it obviously has a synthetical origin. (6.) In addition to ethyl alcohol, there appears to be also a small proportion of some higher alcohol produced, for in the alcoholic distillation the distillate was at first somewhat turbid, but became clear again when a larger quantity had collected. (7.) We have introduced pure cultivations of the same bacillus into solutions of a number of different substances likely to undergo fermentation. The bacillus, as already mentioned, ferments glucose vigorously, it also more slowly ferments cane-sugar, milk-sugar, starch, and calcium glycerate ; the products of these fermentations are being further investigated by one of us. On the other hand, we have been unable to cause it to ferment solutions of dulcite, erythrite, ethylene glycol, calcium lactate, tartrate, citrate, or glycollate. 1889. | Temperature and Specific Inductive Capacity. 307 Iis inactivity towards dulcite is particularly interesting, and fur- nishes another instance of the selective power of micro-organisms towards the most closely allied isomeric bodies. Remembering the relationship of dulcite to galactose and of galactose to milk-sugar (galactose is converted into dulcite by nascent hydrogen, and milk- sugar 1s converted into galactose and dextrose by the action of dilute acids), it is to be anticipated that in the fermentation which this bacillus induces in milk-sugar, the decomposition is limited to the dextrose portion of the milk-sugar molecule. In the action of this bacillus on starch, the latter is in the first instance dissolved, doubt- less through the agency of a diastatic ferment, to which the organism gives rise, as well as to the peptonising one which brings about the liquefaction of the gelatine already referred to. A tube containing . starch-liquid, which had been fermented by the bacillus, gave no blue coloration with iodine, clearly showing that the whole of the starch had undergone transformation into other products. (8.) In view of the characteristic products—ethyl alcohol and acetic acid—to which this organism gives rise, we propose for it the name of Bacillus ethaceticus. XI. “On the Effect of Temperature on the Specific Inductive Capacity of a Dielectric.” By W. Cassiz, M.A. Commu- nicated by Professor J. J. THomson, F.R.S. Received May 24, 1889. (Abstract. ) The variation with temperature of specific inductive capacity was. measured in different ways for solids and liquids. In the case of solids a condenser was made with thin sheets of the dielectric in question, and the capacity measured at different tempe- ratures. ‘The condenser was suspended in an air-bath by wires pass- ing through the top to an insulated support outside. This support was several feet above the bath, so that it was never heated, and its insulation was independent of the temperature of the condenser. The capacity was measured by Professor J. J. Thomson’s method,* and conduction or absorption in the condenser allowed for by varying the time of charge and discharge. The rate of increase per degree centi- grade of the specific inductive capacity was found to be for— Mica between 11° and 110° .... 0:0003 Hibomiber (0. ura nie OG ngs sae. LOSOOOA: Glass EPMA sian: Ole | suchen «O° OOM Another specimen of ,, Ba ont pe leas Krai eh: OO) heal arcade hela) Oe * ‘Phil. Trans.,’ 1883. ne ee a ee ee = 2 = ST ES et. — fk rr Seca — a 358 Mr. E.B. Elliott. On the Interchange of the [June 20, In the case of liquids a quadrant electrometer was immersed in the liquid in question, and the deflection observed at different tempera- tures. The liquid was heated in a water-bath, and the needle and quadrants were attached to insulating supports above the bath. The electromotive force was obtained from a Ruhmkorff coil without the condenser, and with a high resistance between the terminals by which to control the H.M.F. The poles of a second electrometer in air were connected to the poles of the liquid electrometer, and the ratio of the readings of these two gave a measure of the specific inductive capa- city independent of variations of E.M.F. The results are shown in the following table; and in the last column are inserted for com- parison the rate of change of refractive index for the four of the liquids for which Messrs. Dale and Gladstone have determined it. Mean values are given except for these four. For glycerine there is no similarity between the two effects; but for the other three the effects are of the same order of magnitude, although not exactly in the ratio 1 : 2 indicated by the electromagnetic theory of light. Rate of decrease of specific Rate of decrease of refrac- inductive capacity per tive index per degree for degree. A line in solar spectrum. Turpentine. ......| between 20° and 36° 0:0012 | between 10° and 47° 0°00035 be reese eM ts Soe @O0LT aes ti » 62 0:0009 Carbon eae » J5.and 43 0-004 Glycerine :...... » 18 and41 0-006 | between 20° and 48° 000018 Rake i ce 61 0:0053 Bence eee a 19 and41 0.0006 | between 25° and 39° 0:00037 : Seite Aa ui Be Be GOTT pene wis Ck fs 83-0015 Benzine MS ae » 15 and39 0-0014 | between 10° and 39° 0°0004 so52555 5 d8°5 0-0012 Olive Bite as 7 ‘and 68 0°0024 increase Paraffin oil..... » 18 and 54 0:0023 XII. “On the Interchange of the Variables in certain Linear Differential Operators.” By E. B. Etuiort, M.A., Fellow of Queen’s College, Oxford. Communicated by Professor — SYLVESTER, F.R.S. Received June 5, 1889. (Abstract. ) Recent theories of functional differential invariants, reciprocants, cyclicants, &c., have brought into notice a considerable number of 1889.] Variables in certain Linear Differential Operators. 359 ‘ linear differential operators, whose arguments are the derivatives of one with regard to the others of a set of variables connected by any single relation. By aid of such operators, in their quality of annihilators or generators, the forms of classes of functions of the derivatives having properties of persistence in form after various classes of transformations have been discussed with some completeness, and great light has been thrown on the properties of other functions in connexion with such transformations. Often, however, in cases where the transformations dealt with have not been symmetrical in all the variables, the investigation has presupposed that a certain one, or one of a restricted set, of the variables has been chosen as the dependent variable. A complete theory of the interchange of the variables in the classes of functions has been a desideratum, and towards the attainment of that end a theory of the interchange of the variables in the operators has been a first requirement. Such a theory it is the aim of the present memoir to supply for the cases of two and of three variables. I speak of the operators appertaining to the two classes of cases as binary and ternary operators respectively. For the binary operators dealt with I adopt a general form, which is a slight extension of one introduced in anable investigation of Major MacMahon’s, and for the ternary operators one that is closely analogous. I. Binary Operators, By « and y are denoted two variables connected by any relation. L ate bid By #, and y, are meant mag and ae respectively. Let & and 4 be corresponding finite increments of « and y, so that E = Xyyt2Xyy* +n? + ..... ; and consequently E" = (an t+agy?+asy2+ ....- jm SN POON 9g He RD afte te nats , Say. boriike manner let Yim, Y"),, Yim, oe... be defined. Denote the operator == { (u+r9)X | by fu, v5 m, rhe vA 8 din ss imei) ’ ’ the summation being with regard to s, which assumes in turn all integral values not less than the least of m and —n+1. Fractional values of m and n are not admissible, but their integral values may —— 3 = a | 360 Mr. E. B. Elliott. On the Inter change of the Jane 20, be either positive or negative. The value zero of » is admitted, and that of m, though somewhat special, is not excluded. What is sought and effected is the expression of any such operator fu, v; m, n}, in terms of operators of the same form {y’, v’; m’, n'},, in y dependent. ‘The process depends on the use of a certain sym- bolical form for {u, v; m, n}z, and on the proof that a simple factor produces from that symbolical form the symbolical form of the equi- valent y operator. ¥ If m+n =1, so that none of the coefficients of powers of 7 in &” is wanting from {u, v; m, v}z, the inclusive formula of transformation is found to be— 1 ye San, We {r(n+1), # ; n+l, m—1\ ; Tv y and the conclusion is deduced, among others, that there are two classes of self reciprocal operators, a class of positive and one of negative character, viz. :— {—m, 1; m,m—1}, = {-—m,1; m,m—l},, and fm, 1; m,m—1}, = —{m,1; m, m—1}y. Particular attention is devoted to the special cases of m = 0 and — n =—1; also to the transformation of Q and V, the annihilators of in- variants and of pure reciprocants. V of course, not involving the first derivative, is not an operator of the class {u,v; m,n} itself, but is linear in such operators. If m = —x the formula of transformation is found to be Mip,v; m, —mbz = —fym(1—m), n; l—m, m—1lhy+(et+m)y,-“{0, 1; 1, —1}y. In particular ms ny — 4; mM, 3 Lie —1} If m+n<0, = —r say, it is m{p,v; m, —m—r}, = —{vm(1—m—r), w; l—m—r, m—l fy + (nt vm) Ki 10,1; l—r, —lfy +(ntom+v)X, {0,1; 2—r, —1} + (u+vm+vr—v)X'™),_.{0, 1; 0, —1} + (utvm+vr)X™,{0, 1; 1, —L}y. | 1889.] Variables in certain Linear Differential Operators. 361 Il. Ternary Operators. Let x, y, z be variables connected by a relation of any form known orunknown. Let 2s, Yrs, %rs denote respectively ta Oe wiclee dye le. ates ciber eis ; Bie r!s!dy"dze r!s!dzda® r!s! dadys Let ma {Ean h™ = BX e f pt+q . —— 4964: °5 SS 4869 °5 a Region L—D. 5865 5738 5701 5689 5688 5674 5513 5E11 5502 5489 5473 54.47 5425 5418 oe 5408 5403 5396 5335 5296 5295 5271 5250 5246 ° 5226 5224 5224 5209 5207 5205 5192 5188 DAO AMOAWASCWSMAATWSEHEASCSHNOMMONKNMWUASON 1889.] Sun-spot Observations made at South Kensington. 8) 8 ‘8 ‘0 8 3) 2 0 °8 0 a3) “0 3) 5) 2 5143 °2 0 me) 2 3) °2 “4, *4, 20 0 8 5 0 D ‘0 3) 9) On ra (Ju) Or SS TasLE D.—Unknown WIDENED LINES. Ist hundred. 2nd hundred. 6th hundred. 7th hundred. 8th hundred. ool 9th hundred (first half) SS | Oooo sm sw]! SS — eee | OO 12 32 12 33 Region F—b, Per rs ro ro is = SI q = = 5 a = a ie = he es 23 49 21 9 7 61 5 1 4, 31 59 80 1 8 13 4 8 37 4 82 1 1 L 1 2 8 4, ] 31 36 4 1 2 2 36 12 1 2 2 7 19 2 1 2 3 1 1 35 64 13 4, 72 2 2 1 3 1 4, 9 37 52 13 15 53 vt) 29 35 20 bo Go CO OB 47 56 53 12 21 es 392 9th lamnaleenl (first half) —_—— | | Fs _ | | OS | | OU ee iow) ae ne —_ eo) Or S oa . “2 . ° BOAR DWODONHSONSNDOOBDONS DUH ASSSSSMAAHAUASNWWOWONBDAROOMBDAWOS eS 12 i Pe ee aa Gobo on POH WDHH | a cee ; | oC) ; | — ets ; (ve) pe ~~ bo | | : Se; ee yi A Regt, a) ; % ; 1889.| Sun-spot Observations made at South Kensington. Or co) iG in lop) 5043 * 5042 * 5042 5038 5037 5034: 5030 5028° 5020 5017 5009 4995 4975 4971 * 4959 4944, 4921 4910 4912 4910: 4910- 4900: 4895 ° 4893 4891° 4888 4885 °° 4865 ° SDOEMDDODWOUMUMANOSSOHONNODODOVOWOS 5893° 5890 * 5890 ° 5887 5886 ° 5885 ° 5884 ° 5882 ° 5878 ° 5876 5870 0869 5867 5867 5866" 5865° 5865 5864 5864 5863 *2 OU 90 cor) ise) © SCHWONODOANIANWKRANAASUO /1ll 1st hundred. — raiies | 2nd hundred. et Ge} ae] ce! S ro # S 2 a a r ro rS as] ro 5 : 5 E ee a a Fel ae a Fs ee ae S me iar) — Ye) Ne) YX 4 3 1 1 1 3 1 2 2 1 if 1 Region b—D. 1 10 Ai gral 3 1 1 3 t 1 2 5 i 14 8 10 10 7 10 4) 00 ] 2 Ll 16 12 1 Ul 23 1 4, 2 2 1 6 8th hundred. bo a et (Sey to) (Se) 9th hundred. (first half) = 4 e. * 4 cue ta ) 394 Mr. J.N. Lockyer. Further Discussion of the [Nov. 21, Ist hundred 2nd hundred. 3rd hundred. 4th hundred. 5th hundred. 6th hundred. oun hundred. 8th hundred. 9th hundred (first half) a | | es | ee, | ee | a GO to bo eee re Ww bo 10 bo Se Pees we) o> r= Ooo QO CO OO OO ee ee DO > GIO DHONWNMOAUASSSAMSSANVMSMANOASASHBSADSANSUASNSOSCOMNANSONAUKRSONE Lt ke Co a! Lo bo bo ee bo 1889.] Sun-spot Observations made at South Kensington. 1st hundred. 2nd hundred. 8rd hundred. SS ee eee ep) 55 Les 4th hundred. (Je) op) CO Ov Be OULD CO RPOr OW OF bd bo p&p) bo 0 5th hundred. 26 60 6th hundred. 88 &9 7th hundred. a 73 Oe e bo 8th hundred. ot 14 40 40 395 9th hundred. (first half) 38 38 396 Mr. J.N. Lockyer. Further Discussion of the 2/2/2/2/2/2)2]2 13s (281) 3.) Be |) o8 | | ae ete a |= | 4 | 2 | 4 | 3 |9a | ee =) ES tet 5 | Hct og | el 2 Soja.) | 3 3 |e ee ee 5626 °5 al! af 5626 :0 9 4 5622 :0 1 5621 °0 1 5602 :0 if 5595 *2 1 5583°5 2 5572 °-A 1 5567 °5 5566 ‘3 q. 5559-0 1 5ba8 A i: 5541 -O 1 5538 °0 Ah 5537 °0 2 5 5536 °'8 4, 5536°5 4, 7 5536 ‘2 2 5 5536 ‘0 1 5535 °5 Tit 5535 °0 1 55384 :°2 1 5533 °8 if 1 5532 °5 1 5532 :°0 i 5529 °5 3 Pi | 5521:0 2 5520 °4 if) 5515°5 iL iI 6 5511 °4 1 5505 °8 1 5505 °2 1 5493 -6 1 5492 °5 1 5489 -5 A: 3 5486 :O 1 5484°5 = 3 5484-0 4 5482-5 A; 5481-0 2 2 5477-3 3 5475°0 3 5466 :0 1 5463 3 6 if 5462 °5 1k . 5461-0 9 v4 3 1 3 5460°5 ‘8 5460 :O 21 48 15% 21 2 10 at 5459°5 ivil 26 2 5459-0 17 26 29 24, 6d 18 5457-0 1 5456 °0 1 1889.] Sun-spot Observations made at South Kensington. 397 x ; ee ae ee ch eo ee a S aI ro as Z me) line) = = 5 5 5 : 5 5 B.| 88 2 Be al ie a = a 4 a ae SE RAMS Ge Mage) Me es, a Ges male Mee a Qe) esl gan desl = re AN faa) = ite) ite) tt (o.@) oOo— 5444, -O 1 é 6 2 6 2 4, 3 11-8 6 1 4, 1 1 iL 3 1 21 52 37 51 Te 45 17 1 3 11 1 A, 1 5 2 1 1 1 AL: 2 2 1 17 6 alt 1 1 2 23 A 5 6 2 1 2 iL 1 1 1 2 2 1 1 3 1 2 1 1 6 1 1 7 8 1 6 ' 8 y 1 6 8 1 33 48 1 A 2 1 3 1 1 . 2 Ne = h 2 ad We Laat a OP ee ee ee ee + hy ri] > i pel \ 398 Mr. J. N. Lockyer. Further Discussion of the 1st hundred. 2nd hundred. 3rd hundred. 4th hundred. 5th hundred. 6th hundred. ‘7th hundred. %th hundred (first half). hoe tN bo iss) (ep) is i pt bo rH on Lt bo 14 33 pa bo See EEE DO bo bo bo bo me be ® bo aa) a 16, if 5 on BO — or) MBM ONNNOSKRODDMBAMAAMNYOOCHOMANAPSMTONMOBRDMDODNUAWNMNDANOSCHUONDMOWONEES 1889.] Sun-spot Observations made at South Kensington. Fre. 1. Most Widened Lines. F-b Region. YEARS 1879-80 1880-1 1881-2 1882-3 1885-4 1884-5 1885 1885-7 (Hundred 2° Hundred 3°*Hundred 4thHundred St bYundred Hundred 7hHundre 28 8b Hundre 600n77 Unknown substanees. Ii | Number of appearances of known and unknown lines in the F—d region. VOL. XLVI. QE 400 On Sun-spot Observations at South Kensington. [Nov. 21, Fie. 2. Most Widened Lines. b-D Region . 1879-80 !880-1 188I-2 1882-3 1883-4 1884-5 1885 1885-7 1887-8 , . aahiar es reed rae, P th, ) AL ia AL” & tHundred 2"¢Hundred 3 Hundred 4¢*Hundred S'*Hundred 6'MHundred 7 "Hundred 8°*Hundred gthHundred : (furct -nalf id. ) | | | | | eel AS =r] aa Sia (a Fs al leche alee Unknow) - substance ct a aw et a wie haa a Exes Number of appearances of known and unknown lines in the 2—D region. 1889.] Variability in condensing Swarms of Meteorites. 401 The relation of the present observations to former ones is shown in the accompanying diagrams (figs. 1 and 2). [In each observation the six most widened lines in each region are recorded, so that in each 100 observations there are 600 lines in each region. The relative numbers of the lines which are due to iron, nickel, titanium, and unknown substances are graphically represented by the curves. The dotted line refers to the lines of iron, the chain line to those of nickel, the multiple line to those of titanium, and the thick continuous line to those of unknown substances. The minimum period occurred in 1879, and the maximum at the end of 1883, so that the observations now nearly extend through a Sun-spot cycle. It will be seen that the conclusion I arrived at in 1886,* namely, that “ as we pass from minimum to maximum, the lines of the chemical elements gradually disappear from among those most widened, their - places being taken by lines of which we have at present no terrestrial representatives,” is supported by the continued observations, espe- cially in the F—b region. | The 150 observations now added were made by Messrs. Fowler and Taylor, and reduced and mapped by Messrs. Coppen and Porter.— November 1, 1889. ] II. “ On the Cause of Variability in Condensing Swarms of Meteorites.” By J. Norman Lockyer, F.R.S. Received June 27th, 1889. I. Toe Generat THrEory. One of the general conclusions I arrived at in my paper on ‘“¢ Researches on the Spectra of Meteorites ’+ was as follows :—‘‘ Most of the variable stars which have been observed belong to those classes of bodies which I now suggest are uncondensed meteor-swarms, or condensed stars in which a central more or less solid condensed mass exists. In some of those having regular periods the variation would seem to be partly due to swarms of meteorites moving round a bright or dark body, the maximum light occurring at periastron.” And again in 1888, referring to the former class, I added, “If the views I have put forward are true, the objects now under consideration are those in the heavens which are least condensed. In this point, then, they differ essentially from all true stars: like the Sun. This fundamental difference of structure should be * “Roy. Soc. Proc.,’ vol. 40, p. 352. + ‘ Roy. Soc. Proc.,’ vol. 43, p. 154. t ‘ Roy. Soc. Proc.,’ vol. 44, p. 81. 28 2 402 Mr. J. N. Lockyer. On the Cause of [Nov. 21, revealed in the phenomena of variability, that is to say, the vari- ability of the bodies we are now considering should be different in kind as well as in degree from that observed in some cases in bodies like the Sun or a lyre, taken as representing highly condensed types. There is also little doubt, I think, that future research will show that when we get short period variability in bodies like these, we are here really dealing with the variability of a close companion.” The recent work of Chandler* on the colours of these interesting objects, and the relation of colour to period, furnishes further tests of the theory which I suggested as to their origin. Variability due to Subsidiary Swarms. Briefly, this was that in the case of the stars of Group IIL, which spectroscopic observations show to be composed of uncondensed Fie. 1.—Diagram slowing the probable origin of variability in condensing swarms. * * Astr. Journ.,’ No. 179-180. 1889.] Variability in condensing Swarms of Meteorites. 403 swarms of meteorites, the variability is produced by the revolution of one or more smaller swarms round the central swarm, the maximum luminosity occurring at periastron passages, when the revolving swarms are most involved in the central one. Fig. 1 illustrates this suggestion in the simplest case, where there is only one revolving swarm, as in Mira Ceti. The range of variability depends upon the eccentricity of the orbit and the periastron distance of the revolving swarm. According to this theory, the normal condition is that which exists at minimum, and in this respect it resembles that suggested by Newton, namely, that the increase of luminosity at maximum was caused by the appulse of comets. All other theories take the maxi- mum as the normal condition and the minimum as a reduction of the light by some cause, such as a large proportion of spotted surface or eclipses by dark bodies. In the variables of the Algol type, where the periods are very short, there can be no doubt, after the Henry Draper Memorial photographs, that the eclipse explanation is the true one. But in the variables of Group IJ, where the period is about a year and the luminosity at maximum in the generality of cases is about 25() times, though in others it runs up to 1600, that at minimum (corresponding to a difference of six magnitudes), it is obvious that the eclipse explanation no longer holds, on account of period, and also that the spotted surface explanation is inadmissable on account of range. If, however, the minimum be taken as the normal condition, and the effects of the revolution of such a swarm as [have assumed be considered, both length of period and range of variability can be explained. In this class of variables the rise to maximum is more rapid than the fall to minimum, and, according to my explanation, the sudden increase is due to the first collision between the two swarms, while the fall to minimum represents the gradual toning down of the disturbance. Tests of the Theory. In the Bakerian Lecture (p. 84) I showed how this explanation of variability bore four distinct tests. he first test was that Group IL should be more subject to variability, than any other group; and I _ showed that 1 out of every 7 stars of Group II are variable, whilst only 1 in 659 of the stars included in Argelander’s catalogue are variable. The other tests were :—(2) when the swarm is least con- densed, we shall have the least results from collisions; (3) when it is fairly condensed, the effect at periastron passage (if we take the simplest case, where there is only a single revolving swarm) will be greatest of all; (4) in the most condensed swarms there will be little or no variability, because the outliers of the central swarm may be 2 ee ody oe ee a 1 Spee 404 Mr. J. N. Lockyer. On the Cause of — [Nov. 21, © drawn entirely within the orbit of the secondary body. I gave tables to show that these tests were satisfied by all the variables included in Dunér’s catalogue of red stars.* In the tables which follow, it will be seen that by far the greater number of variables in the group under discussion fall in species Y and 10, which may fairly be taken to represent the mean condensation, there being in all 15 species. — There can, therefore, be no doubt that the three tests just referred to are fully satisfied. In this paper I propose to further test my theory by the colour observations of Chandler and by the question of irregularity, con- fining myself to stars known to belong to Group II of which Chandler gives the degree of redness. The stars selected for discussion are the IIla variables from Gore’s revised catalogue. II. DETAILS OF VARIABLES OF Group II. _ The following tables contain all the particulars of stars with periods varying from 50 to 500 days. Gore’s, Chandler’s, and Dunér’s star numbers are given as well as the star’s name. The magnitudes of the variable at maximum and minimum, and also the period, have been taken from Gore. Oolour Notation. On Chandler’s colour scale 0 corresponds to pure white, 1 to white very slightly tinged with yellow, 2 and 3 to deeper yellow tinges, 4 to orange, 5, 6, 7, 8 and 9 to gradually deepening reds, and finally 10 corresponds to the deepest red stars known, such as R Leporis. The colour notation employed by Dunér is as follows :— | Tyr], sete ee ele Almost absolute red. TUG] \e 6 arose ee eae eee Red-yellow foncé. BD] rs Serr eeetse Red-yellow. rh aes erg eS a ee Yellow-red. IMGs ona oscs0s53 553856 Clear yellow-red. In the Bakerian Lecture for 1888 I gave a series of tables in which the stars of Group II were classed in different species according to their spectra. I have accordingly given with each variable the number expressing the species to which it belongs. In some cases, the details have not been sufficient to assign the star to a definite species, but have been enough to determine whether it was near the first (Species 1) or the last (Species 15). In such cases, the words ‘‘early”’ or ‘‘late” are appended. Where the species of a star is doubtful, the word “indeterminate” expresses that fact. * “ Les Etoiles 4 Spectres de la troisiéme Classe.’ (Stockholm, 1884.) 405 6 I g 881--0ZT | §-4—-L-9 | 9-8-4 Tusk M | 699% PLL BOLT ‘oqVUTULLOJOpUy Ip 0-3 q. 181. Eee WG ot fh efnoodinA YW | 19% 0962 WE "agun(T UI JON a ZS 991 | &.0T 9-8 “UL 880) Y — 8r6S G1 ‘AT regy ty 0-8 O61 G. 31 0-8 ' eiqry § | SOT POPS 101 ‘oqer] If €-1 1-GhLT | 6-OI—OT | ¢-£—-9-9 STUISITA Y | BT 1Zcv 8 II ap g TST—Sel | Z-F—L.8 B-8 wnsourmop lk} gg aida 8¢ 6 rf DB T- 91 Gr >| 2.86. 1 WOM! 08 Ch8 9T “t9UN “LOT PUBL ‘soloodg Espa ie ‘poled “UIT “XVI “OULR NT ‘igunq | ‘daypuvyog | . ‘et04 *IMOTOD ‘shep (0G 0F OOT JO Sported YyIM sofqurre A ‘oVCULUILOJOpUyT fay g G64-L9 66.6 Gg. 8 efnoedna g 88% 9012 EST 8 Ip @ | &SI—OoP Z-9 G sTTno1oH (0g)4 PST Z16S T@ ‘toun( =| ‘leypueyo ‘solvodg ———____—_—___—_—___—| ‘poreg “UIT “XBT *OULB NT ‘rounqg =| ‘deypueypH “OL0-f) Variability in condensing Swarms of Meteorites. “INO[OD ‘skUp QOT 0} OG Jo spotzod yytM sorqerte A 1889.] aa NX > = Gi, On the Cause of 2 Mr. J. N. Lockver. © i) —r “Ape ‘OJ VULULIOJO PAT "OyeryT *AT.LeOoy ssatedg fy 9. OL rat ee a v1 = Loy UL Ip 0.2 GS. PPS el > fy Ze Z- 183 ¢- 11 1p Le azz. | G- GI—-8- IL fay leg CG. 8S d3 es 9.2 G. 992 D6 = fis]! Paoe Mesacle=oe2 1 ty Z-8 8-26 | 8-GI—Z-0T Ip Z 9.G¢¢ ST Ip ile P- 9G Zl = ‘rgunq | ‘deTpuvyO ‘poled “UIT “INOTOD 9-8-—8-4 0-4 1-8-4 b-8—Z- L ¢-8—P-9 g-8—G. L a Xe] THBIWSES Y sI[MoLeyT SIUOOBIC YY SI[No1o FT AA sjoog Y tpredojouuy yy 8100 A STUISITA 1) ‘fem @srq g ‘fey wag etpdTy § ae “OUR NT ‘sep QOY OF 00% JO Sported YALA sete A “foun “aTpUByO) SPT SET DCsL Pol 96 G6 D6 98 s8 68 09 "2304 Variability in condensing Swarms of Meteorites. 407 1889.] ‘sorloodg *“TOUNC 1D ° GO OD SH OD 10 SH 1 6 RIP OSSAHPH SW 19.0900 10 OO SH Wg 6 O re O qnc ° "INOTOD ‘skep OOF 0 OO JO sported qyrm sopqerre A ‘LaT PURO 88é O6& SVE 00€ V- GOS 608 9. 496 V- O9€ 9-81& G6 G- COE SI€ L- VLE V- Vos G-G6& =F SOE 9- 96& inches &- [&€ cvs "poltog IL 6:6—G¢:-6 Gc: TL[—6: OT 6 Cl = GeGle-Gu iL ie G.Z1 ¢- IL 6 fan (Sit OI—¥-6 Il > Z-1L > 10) Gee GL > Cl Z-6—¥:-6 G.6—2Z:8 Gigl = “UTIL ¢g.8—8. L.9—G. Opi Z 8-9 T-8—9. 1. L—6. 9-2—9- 8-L—T 6-1-8. 8 T-8—O L-9—6 EA €-8—<é- 0- 8—<@ Sia a! 0-6— 6: 8—6 0-G—L. 6-8—4 "xB ererorwowow © €© © 109 10 be © 109 qaenby y roydey J, | emby yy siyuediog — rponrydO wf sI[NoLeFT g siquoditeg 3 BOLD g HES) eal SILOJVAD) Ye Tey stg sIuooTT YY “UT, SIMOeT -Y TLOURD Ye "UIT SURO § SIUONIQ (BAON) 1 LMT, Y sporty 1999 (eat) 0 UNOS YY "OULG NT “ToUNC, ‘LoTpuvyO "O10 On the Cause of [Nov. 21, Mr. J. N. Lockyer. 408 8. 80P + PSP elh CoP O1 0-4 fay L. 0% AT AVOL 8-4 oy 98h ee ny ‘LoppuryO “gun, ‘soroody ‘porto “INOTOD 8-éL €1 9: TI—P: TL 6 OL 6: 6L = 1. 31—%-6 EAI. 8-9-8.) XU] arodorsstd tus X rusk) Y stjnod0 FT weIpATT Y sIUONIO § BSINY IY Bpoumocpuy erodorssty J, “OUR NT 1&3 I8l “r9UN(T 008 OZTL SFOL 6889 IBV Pr6L SS8T éIL LOL ‘LoTPUBY DH 68T PST TST 6IT 68 VE G& T ed ‘aL04) ‘skup 0G 01 OOF Jo sported qIIM sorqvite A 1889.] Variability in condensing Swarms of Meteorites. 409 III. Tae Reptation or Contour To PErRIop. Mr. Chandler’s Observations. In the tables given the particulars relating to period and range of variability are taken from Gore, and Chandler’s colour-numbers are placed in a separate column. Mr. Chandler has shown* that there is an intimate connexion between the length of period of a variable star and its colour. In general, the longer the period the redder the tint. If the period is between 500 and 600 days, the mean redness on his scale is about 75; for periods of about 300 days, it is about 3; and for shorter periods itis lor 2. This is exactly what would happen if my theory were true. In order to investigate the cause of this relation it is necessary that I should refer to Chandler’s work in connexion with my previous classification of the 297 bodies of Group II spectroscopically observed by Dunér. The Relation of Colour to the Degree of Condensation in Swarms of Group IT. In the Bakerian Lecture I provisionally divided the bodies of Group II into fifteen species, the first being the least and the last the most condensed swarms. If then the degree of condensation of a swarm has any relation to colour, the work of Chandler on the colours of variable stars, taken in conjunction with this classification, ought to enable us to determine the nature of such relation. In order to determine Chandler’s colour-numbers corresponding to these, tables were prepared comparing Dunér’s colours of the variable stars of the group with the colours assigned by Chandler to the same stars. Two stars which Dunér gives as Rrrj occur in Chandler’s list, the colours being 6°9 and 8°1 respectively, or a mean of 7:5. The colour-number corresponding to Rrrj has therefore been taken as 75. Similarly, there are ten Rrj stars in Dunér’s list for which the mean colour-number assigned by Chandler is 5:9, and so on. Dunér’s Colour = Rrrj. No. (Dunér). Colour (Chandler). 92 Gr 106 8-1 Mean 7 °5. * ¢ Astr. Journ.,’ No. 179—180. 410 Mr. J. N. Lockyer. On the Cause of No. (Dunér). a7 Jl 221 Dunér’s Colour = Rrj. Dunér’s Colour = Rj. Colour (Chandler). Ard Mean 4:2. Dunér’s Colour = Jr. 1889.] Variability in condensing Swarms of Meteorites. All No. (Dunér). Colour (Chandler). 125 2°0 159 27 187 2°0 222 3°6 100 16 293 43 ee) 2°0 Mean 2:4. Dunér’s colour = Jjr. None common to Dunér and Chandler. Mean colour, say, 0°7. It will be seen that the increments for one colour stage of Dunér are 1-6, 1-7, and 1°8 respectively, or a mean of 1:7. Since there are none of Dunér’s Jjr stars in Chandler’s list, we may use this increment to approximate to the colour; this gives us the number 0'7. We thus get :-— Dunéz’s colour. Chandler’s number. Rrrj Go Ryrj a9 Rj 4-2 Jr 2-4, Jr Q-7 Using these mean numbers, we may determine the mean colour- number associated with each of the fifteen species into which Group II has been divided. The following tables show the results obtained. Dunér’s No. Colour. Species 2. 56 4:2 93 4-2 220 24, 223 2°4 246 2°4 Mean 3°71 Species 3. 42 2°4, 53 2-4, 70 2°4, 185 2°4, 198 274 228 42 276 0°6 290 2°4. Mean 2:4. | | | 412 Dunér’s No. Species 4. 7 95 110 Species 5. 89 153 154 173 De 258 267 271 Species 6. 6 Species 7. 24 Colour. 0°6 2°4, 2°4, Mean 1°8. 4-2 2°4: Paka - aS an SS Mr. J. N. Lockyer. On the Cause of [Nov. 21, a 1889.] Variability in condensing Swarms of Meteorites. Duner’s No. Species 8. Species 9. 181 195 229 241 249 252 256 269 270 275 284: 413 “ie Al4 Mr. J. N. Lockyer. On the Cause of fas Dunér’s No. Colour. 65 2°4, 66 2°4, i) 118 4:2 | 1} 59 i" 148 2°4, | 156 5-9 a 158 Ar 2, i 162 42 i 165 . 4:2 | 74, 4-2 | 175 AQ | 176 42 183 4-2, | 186 42 | 204, Ar, | 217 42, | 221 ; 5°9 | 237 2°4, | 255 — 2°4 266 42 277 2°4, | 281 2:4, ‘ 293 2-4, | Mean 3°9. | Species 10. 4 | | fo 18 4:2, 28 4:2 30 42 | 86 42, | 91 59 92 75 | 131 2-4 | 141 59 172 59 196 42, O32 4,2, 239 59 Mean 5 Species 11. 95 2A. yD) 2°4, 87 42, 1889.] Vurtability in condensing Swarms of Meteorites. Ald Dunér’s No. Colour. 149 4-2 152 24 171 2-4 a Ae 24 ou 2-4 193 2:4 7) 2-4 Lo 2-4 212 2°4 218 4-2 234 2°4. H 245 2-4 288 2-4 Mean 2°7 } |; Species 12. 27 2-4 46 2-4 | 51 2-4. 52 2:4 60 2° 4: 78 4-2 117 24. 122 0-6 126 2:4 129 2°4 133 2°4 164 4-2 215 2°4 264 2:4 Mean 2°5. Spectes 13. 1 2-4, 2 4-2 16 0-6 1 2°4 26 0-6 32 2-4, 3 2°4: 36 2-4 38 4:2 40 2-4 54: 42 6] 2°4 62 2°4. bo | VOL, XLYI1. | 416 Mr. J. N. Lockyer. On the Cause of [Nov.21, ~~ i Dunér’s No. Coiour. i 64, 2:4, 69 2-4 75 9:4, 82 0-6 | 104 2-4 | 109 24 116 24, 120 9:4, i 121 9:4, | 124 9:4, | 130 9-4, | 132 9-4 144, 9:4, | 145 24 | 146 9:4, | 155 9:4, 160 9-4, | 182 4-9 200 0-6 | 203 9:4, | 205 24, 207 od, | 211 9-4 240 24 ' 243 9-4, : 24d, 2:4. ( 268 9-4, | 280 2-4, O87 9-4, | 292 9-4, 4 294, 2°4 | Mean 2:4. | _ Species 14, 22 2°4 49 9-4, | 90 9:4, | 94, 2:4, 107 2:4, { 111 Ard \ 113 2°4, } 140 9:4, | 167 2:4 if 1889.] Variability in condensing Swarms of Meteorites. Dunér’s No. 169 i) 180. 187 250 282 138 Species 15. 41 | 50 96 101 136 139 147 Species 15. 190 226 235 265 279 2°4, 274: Mean 2:7. Al? We thus get the following colour-numbers corresponding to the fifteen species :— Species. (8 oO om WD eS las su) (1 star) (?) (5 stars) » ) » ) Mean colour-number. Ar2 272 oe " - “aoe Sgr > OR ee WS aT ee a 418 Mr. J. N. Lockyer. On the Cause of — [Nov. 21, The remaining stars observed by Dunér are not imeluded in the classification at present, owing to insufficient details. The result of this comparison of Dunér’s and Chandler’s observa- tions, taken in conjunction with my classification in species of the bodies of Group II, goes to show that the swarms with a mean con- densation are the reddest. For, although the results are not quite so uniform as might be desired, there is a decided maximum of redness in species 9 and 10, which may fairly be taken as the swarms with mean spacing. -The greatest discrepancy is in Species 1, but here the result depends upon the observations of one star, and even that is not definitely known to belong to Species 1. (See “ Bakerian Lecture,” p- 65.) . It may be objected that the foregoing series of numbers is not sufficiently regular for any trustworthy conclusions to be arrived at. But the very decided maximum in Species 10 is of itself sufficient evidence that the irregularities on both sides of it are due to the difficulties of observation. I have gone over Dunér’s observations of the spectra and colours of the bodies of Group II without reference to my temperature classification, and the result shows that where the spectra are described as identical, the colours sometimes differ con- ‘siderably. The table on page 419 shows that this is the case. The numbers in the vertical columns indicate the numbers of stars of any particular colour associated with a particular spectrum. ‘Thus, amongst the stars with a spectrum containing the band 1—10 uniformly developed, 3 have the colour Rrj, and 5 are Rj. It will be seen, therefore, that, even if my classification into species be not accepted, the relation between colour and spectrum in the present state of our knowledge is not absolutely definite. [This is probably to a great extent due to the variability of the stars of the group. All of them may be more or less variable, and it may often have happened that the colour of a star has been recorded at one time and its spectrum at another, when the colour was slightly different. Some of the slight variations observed may also be due to variation in the atmospheric absorption.—November 1, 1889. ] On reference to the tables of variables which I give in this paper it will be seen also that the relation between colour and period observed by Chandler is only a general one. We may, therefore, for the present regard aes swarms with mean spacing as the reddest. The sparsest swarms vary from blue to greenish-white, so that the redness will gradually deepen in passing from these to the mean swarms. Again, in passing from the mean swarms to the most condensed ones, the redness must gradually dis- appear, for we know that the stars of Group III are yellow or white. ‘T‘he following represents the colour-condition of stars of Group II both more and less condensed than the mean swarms, 1889.] Variability in condensing Swarms of Meteorites. 419 Spectra. Ryj. | Die eC eae ies ibe Bands narrow and pale, red ai aie BG 2 oteon aCe Ne ogee ee en Rae Fuotogrdse nonce | == Bands wide and pale. . note 3 2—8 bands moderately “wide and ‘dark, 2 and 3 strong .... a ehafeal ara stat [een Bands wide and dark, ‘red strongest. . ee et 2—9 bands moderately wide and dark, 2 and 3 strongest . ve meee (9 ae 1—9 bands moderately | wide) and dark, "2 and 3 strongest ..... 1—10 bands wide and moderately dar k, ‘red str rongest 1—10 bands well developed and equal . : 1—9 blue bands most strongly developed .. 1—9 wide and dark . 2—9 wide and dark, blue strongest . 2—9 wide and dark . Sage Pic 2—10 wide and dark . Bands wide and dark, blue strongest. Seas 2—8 wide and dark, blue rere Ss oe cg as Bands wide and dar Ic. Beasts 2—8 wide and dark.. 2—8 narrow and dark . a Bands narrow and pale, blue stroupest cen ec 2, 3, 4, 5, 7 and 8, 7 and 8 Sareeie Sie OE 5 None 2,3, 5,7, 8.. Bice ns idee Zee Ts peas Mebatats a eiatbisetee aire als 2,3,7 Bete eerie Indeterminate .. | on ox | vo ie | | 4 | mr. © | hee oe © FR WH OLOI OL OO lal & pan i) OWwWwonwnaure Oo cot tale | leew ee} ee || es pt oan | w | =! (ep) ie! bo c CO op) 176 12 -eddish-yellow, | yellowish-red, Group Il......< red, | yellowish-red, -eddish-yellow. Hence no definite conclusion as to temperature of Group II stars can be arrived at by colour observations alone, since stars cooler than the mean, as well as hotter, give the same colour. The Cause of the Relation between Colowr and Period. On reference to the tables of variables, it will be seen that there are none less condensed than Species 7. This means that the sparsest swarms either exhibit no variability at ali, or their variability is of such a character as to escape notice. The reason for this is not far to seek. Firstly, if there be any revolving swarms with small orbits, they will never be entirely out of the central swarm, and their effect will simply be to produce a general increase of brightness of the swarm. 42() Mr. J. N. Lockyer. On the Cause of — [Nov. 21, Only revolving swarms with large orbits will therefore be effective in producing variability, but even these will only cause variability of short range, since the number of collisions at periastron passage will be small, the swarm being sparse. In the sparsest swarms, therefore, the variability will be of a long period and the range will be small. These are no doubt the causes of the variability having been over- looked. ‘When we pass to the mean swarms, however, the variability ‘becomes more strongly marked. Cometic swarms of short period, if they exist at all, will still only produce a general brightening of the central swarm, and the swarms most effective in producing variability will therefore be those with moderately long periods. The range of variability will depend upon the eccentricity of orbit and the periastron distance of the revolving swarm, as in the general case. As the central swarm becomes more and more condensed, and therefore gradually loses its redness, only shorter period swarms will be effective in producing variability, as ‘the outliers will have been drawn entirely within the orbits of longer period swarms, if they - exist at all. Still further condensation of the central swarm will draw the ‘outliers within the orbits of the revolving swarms, which would | produce variability in the swarms last considered, and now only very short period swarms are concerned. At the same time the colour will have become yellow or yellowish-white, the swarm having passed from Group II to Group ill. . It will be seen that my theory perfectly explains the general relation of period to colour which has been observed by Chandler and previously by Schmidé,* and in fact demands it. The range of variability does not appear to bear any relation to the periodicity (except perhaps in the sparsest swarms), and this is only what we should expect, as the conditions on which the range depends ‘(periastron distance, and eccentricity of orbit of revolving swarm) ‘are special‘to each star. Cometic swarms in our own system follow “no general rule as regards the eccentricities of their orbits, or their perihelion distances. IV. THe IRREGULAR VARIABLES OF Group II. ‘The next test is that of irregularity. The apparent irregularities in the variability of stars in the group under discussion are, on my theory, produced by the revolution of several swarms of meteorites at different rates and different distances round the central one. The swarms most subject to irregularity should, therefore, on this view, be those which are most likely to suffer from the effects of the * Quoted in ‘ Observatory,’ Feb., 1889. 1889.] Variability in condensing Swarms of Meteorites. 421 ereatest number of revolving swarms. These will not be the sparsest swarms, for the reason that the short period swarms will only produce a general brightening, as already pointed out, leaving the long period swarms predominant. Neither will they be the most condensed, because most of the cometic swarms will sweep clear of the central swarm at periastron passage. They must, therefore, occur in the swarms of mean condensation, if anywhere at all, though mean swarms need not necessarily exhibit irregular variability. The facts observed show that out of the five irregular variables of Group II, three have colours indicating a mean condensation, while two appear to be a little further condensed. Irregular Variables. oy 9 g Colour. = : E - a oh oO Sx m o Cale oe alee z a || 2 3 & S ras i ss | S | 2 | Chandler. | Dunér. = 18 | 1072 29 | p-Persei 3°4—14°2} — 2 Jr 8 37 2098 50 | a-Orionis | 1 1°4| — 6 Rj 15 129 | 6181 |-196 | a-Herculis| 3°1 |3°9| — 5 Rj 10 179 | 7803 | 269 |yp-Cephei | 2°7 |4°8) — 6°2 Rrj 7 184 8273 | 281 | B-Pegasi 22 |2°7| — 2 Jr 9 The spectroscopic observations confirm the conclusion that irregu- larity mostly occurs in mean swarms; it will be seen that with the exception of « Orionis, which is only very slightly variable, the species to which the irregular variables belong are 7—10, indicating mean condensation. V. Brignut HyprRogen IN VARIABLE STARS OF Grovp II. I have already pointed out* that in the class of variable stars under consideration the bright lines of hydrogen might be expected to make their appearance at maximum. For since the bodies of Group II are very much akin to nebule, an increase of temperature such as occurs at maximum should be accompanied by the appearance - of bright hydrogen, because a greater quantity of incandescent gas would then occupy the interspaces. Under normal conditions there are neither bright nor dark hydrogen lines in the spectra of bodies of Group II, the simple and sufficient explanation being that the bright lines from the interspaces balance the dark lines from the meteoritic nuclei. ‘“ Anything which in this condition of light-equilibrium will increase the amount of incan- * Bakerian Lecture, 1888, p. 83. 422 Variability in Condensing Swarms of Meteorites. [Nov. 21, descent gas and vapour in the interspaces will bring about the appearance of the hydrogen lines as bright ones. The thing above all things most capable of doing this in a most transcendental fashion is the invasion of one part of the swarm by another moving with a high velocity. This is exactly what I postulate. The wonderful thing under these circumstances then would be that bright hydrogen should not add itself to the bright carbon, not only in bright line stars, but in those the spectra of which consist of mixed flutings, bright carbon representing the radiation.”’* That the bright lines of hydrogen do make their appearance at maximum, in some of the stars at all events, is placed beyond doubt by the recent observations of Mr. Hspin at Wolsingham. On August 13, 1883, Mr. Espinf noted ‘‘a very bright line, appa- rently F,’”’ in the spectrum of R Cygni, the maximum of the star occurring on July 19th. The spectrum of o Ceti was also observed by Mr. Hspin}+ on October 23rd and 30th, 1888, the maximum of the star occurring on September 28th. Dunér’s bands from 1 to 10 were seen, and the observer noted that on October 30th, when the star had faded con- siderably, bands 8, 9, and 10 seemed to be broken into two, but he was doubtful whether these interferences were due to bright lines or not. A brilliant line was observed in the violet, which was thought to be h (hydrogen). It is very probable also that bright F was present on this date and caused the second maximum in band No. 9. Bright lines of hydrogen and other substances were photographed in the spectrum of Mira by Professor Pickering in November, 1886, the maximum oceurring on November 14th. Mr. Maundert{ observed bright hydrogen (G) in the spectrum of Mira on October 5th, 1888, but on December lst it was not recorded. Mr. Espin has also announced in a recent circular (April 2nd, 1889) that there are bright lines in the spectra of R Leonis and R Hydre. He states that “the spectra of R Leonis and R Hydreze contain bright (hydrogen?) lines, first seen on February 25th. Observations confirmed, through the kindness of Mr. Common, by Mr. Taylor, at Ealing, who sees two in R Leonis and one in R Hydre.”’ Both these stars were near their maxima at the time of observation, that of R Leonis occurring on March 23rd, and that of R Hydre on February 17th. [Another circular (October 3, 1889) states that ‘“ Bright lines were seen in the spectrum of R, Andromede on September 25th, the F line being very bright.” The maximum occurred on July 25th.— November 1, 1889. | * Bakerian Lecture, p. 838. + ‘ Ast. Soc. Monthly Notices,’ vol. 49, p. 18. { ‘ Ast. Soc. Monthly Notices,’ vol. 49, p. 304. 1889.] On the local Paralysis of Peripheral Ganglia, &¢. 423 The appearance of the hydrogen lines at the maximum and their disappearance as the stars fade will no doubt eventually be found to be among the characteristic variations of the spectrum which accom- panies the variation of light in stars of this class. VI. ConcuLusIon. As far as Group II is concerned, I think it will be granted that the meteoritic theory of variability is quite in harmony with the facts observed, considering that the observations are still incom- plete. The theory does not require that all the swarms of the group should be variable, but only those which are condensing double or multiple nebule. At the same time it requires that this group should be more subject to variability than any of the others, and this is one of the best established facts of modern astronomy. Not only are these general demands satisfied, but the theory bears the strain put upon it when it is used to explain the finer details, as I have shown in this paper. I]I. “On the Loeal Paralysis of Peripheral Ganglia, and on the Connexion of different Classes of Nerve Fibres with them.” By J. N. Laneury, F.R.S., Fellow of Trinity College, and W. Lee Dickinson, M.R.C.P., Caius College, Cambridge. Received September 7, 1889. Hirschmann* has shown that after a moderate dose of nicotin stimulation of the sympathetic nerve in the neck causes no dilation of the pupil. He concludes that nicotin paralyses the endings of the dilator fibres in the pupil. In the course of some observations on the physiological action of nicotin, we had occasion to repeat Hirschmann’s experiment; we found in the rabbit that 30 to 40 mgrms. of nicotin injected into a vein stopped the effect of stimulating the sympathetic in the neck, not only on the pupil, but also on the vessels of the ear. A paralysis of the vasomotor fibres of the sympathetic had been suggested by Rosenthal,y+ on the ground that nicotin causes a state of congestion in the vessels of the ear of the rabbit. Since we had been much struck with the profound action of nicotin upon the central nervous system, and since it had seemed to onet of us in some previous experiments with atropin that the secretion of saliva from the sub-maxillary gland of the cat failed earlier on stimu- * Hirschmann, ‘Arch. f. Anat. u. Physiol.,’ 1863, p. 309. + Rosenthal, ‘ Centralb. f. d. Med. Wissenschaften,’ 1863, p. 737. { Langley, ‘ Journal of Physiology,’ vol. 1, 1878, p. 89. 424 Messrs. J. N. Langley and W. Lee Dickinson. ‘[Nov. 21, lation of the sympathetic nerve in the neck than on stimulation of the sympathetic fibres proceeding from the superior cervical ganglion, it occurred to us that the action of nicotin might be due to a paralysis of the nerve cells of the superior cervical ganglion, and not to a paralysis of the peripheral endings of the sympathetic nerve. On testing this view, by stimulating the sympathetic above and below the superior cervical ganglion after injection of nicotin, we found that, ~ whilst stimulation below the ganglion produced no effect, stimulation above the ganglion produced a dilation of the pupil and a constriction of the vessels of the ear, as if no nicotin had been given. ‘The effect of stimulating the nerve fibres above the ganglion is not abolished by an amount of nicotin four to five times as great as that sufficient to abolish the effect of stimulating the sympathetic nerve in the neck. This point, however, we shall consider more in detail in a later paper upon the general action of nicotin. We are here only concerned with the fact that after a certain dose of nicotin stimulation of the sympathetic fibres below the ganglion does not produce dilation of the pupil or constriction of the vessels of the ear, whilst stimulation of the sympathetic nerve fibres above the ganglion produces these changes im the normal manner. It is conceivable that the difference in the effect of stimulating above and below the ganglion might be due to the nerve fibres being medullated below and non-medullated above the ganglion, and to nicotin paralysing the former and net the latter. But, in the first place, although it is probable, it has not been shown, that the dilator fibres of the pupil and the vaso-constrictor fibres for the ear are medullated below the ganglion; and, in the second place, it is obvious that medullated fibres as such are not paralysed by nicotin, since for some time after the stage in which stimulation ef the sympathetic in the neck fails to affect the pupil or the ear, stimulation of a nerve such as the sciatic will cause movement both directly and reflexly, that is to say, at this stage neither the medullated sensory fibres nor the medullated motor fibres to skeletal muscle are paralysed. The method of action of nicotin can be tested in a more direct manner. If the alkaloid preduces its effect by acting upon the nerve below the ganglion in consequence of any peculiarity of structure obtaining there, the local application of nicotin to the nerve should abolish its irritability. If, on the other hand, it produces its effect by acting upon the nerve cells in the superior cervical ganglion, the local application of nicotin to the nerve should have very little effect upon the nerve irritability, but the local application to the ganghon should abolish the effect of stimulating the nerve centrally of the ganglion. In making the experiment on these lines, we isolate the sympathetic nerve in the neck, the superior cervical ganglion, and to a certain 1889.] On the local Paralysis of Peripheral Ganglia, &c. 425 extent the filaments proceeding from it to the external and internal carotid arteries. Having stimulated the sympathetic in the neck, and observed its normal action on the eye and on the ear, an inch and a half or so of the nerve is brushed over with a 1 per cent. solution of nicotin. Any excess of fluid around the nerve is removed by blotting paper, and the moistening the nerve with dilute nicotin is repeated. The central part of the nerve is stimulated several times at intervals of about two minutes; it produces the usual dilation of the pupil and constriction of the vessels of the ear. The ganglion and the filaments proceeding from it are then brushed over with 1 per cent. nicotin; the sympathetic in the neck is again stimulated; it is found to be com- pletely without effect; stimulation of the filaments running from the ganglion to the arteries produce the normal action. Hence nicotin paralyses the cells of the superior cervical ganglion. Besides the dilator fibres for the pupil and the vaso-constrictor fibres for the ear, the cervical: sympathetic contains vaso-motor fibres for the head generally, and secretory fibres for the salivary glands.* On these we have made a few experiments only; but, so far, we find that (in the rabbit and cat) after the application of nicotin to the superior cervical ganglion stimulation of the cervical sympathetic no longer causes secretion or pallor in the sab-maxillary gland, nor pallor of the mouth. Im fact, after nicotin has been applied to the ganglion, we have been unable to detect any effect from stimulating the sympathetic in the neck. We conclude that the dilator fibres for the pupil, the vaso-constrictor fibres for the ear (probably also those for the head generally), and the secretory fibres for the glands end in the cells of the superior cervical ganglion. The paralysis of the cells is produced with remarkable ease; in the rabbit and cat a complete abolition of the effects of stimulating the sympathetic in the neck results from a single “ painting” of the superior cervical ganglion with a small brush dipped in 1 per. eent. nicotin. The experiment is most easily performed in the rabbit. In the cat the simplest method is to dissect away the connective tissue on the mesial and dorsal side of the ganglion, to pull upwards and laterally the muscles lying by the carotid, and then, without separa- ting the ganglion of the trunk of the vagus from the sympathetic -gangloon, to moisten the exposed medio-dorsal surface of the latter with dilute nicotin. Of course, by this method, some nicotin will be almost certainly applied to the ganglion of the trunk of the vagus; we may mention, as showing that the nicotin affects the nerve fibres * According to Heidenhain (‘ Pfliiger’s Archiv,’ vol. 5, 1872, p.316), when about 15 mgrms. of nicotin are injected into the vein of a dog, the sympathetic secretory fibres are for a short time paralysed—presumably this is for stimulation of the cervical sympathetic. 426 Messrs. J. N. Langley and W. Lee Dickinson. [Nov. 21, comparatively little, that, if in the above experiment nicotin 1 pev cent. be copiously applied to the vagus or to the ganglion trunci vagi, the inhibitory power of the vagus upon respiration is apparently unaffected. : Although in an experiment conducted in the manner just described there is little or no diminution of irritability of the sympathetic nerve on applying 1 per cent. nicotin to it, repeated application of nicotin to the nerve does, as might be expected, lower and finally destroy its irritability. And if the nerve is ligatured and a long piece isolated so that the blood supply to it is cut off, a great reduction or even abolition of irritability takes place on soaking it with 1 per cent. nicotin. But, with proper precautions, the difference in the effect of applying nicotin to the ganglion and to the nerve is so great that there is practically no danger of confusing the action on the cells with that on the nerve fibres. In the nerves of the frog, the effect on the nerve fibres, other things being equal, has. seemed to us to be greater than inthe mammal. Since nicotin is alkaline, it is possible that a part of its injurious. effect may be due to its alkalinity. And in fact, if a 2 per cent. solution of nicotin be neutralised with sulphuric acid, and diluted with water so that it contains 1 per cent. nicotin, its effect both upon nerve fibres and upon ganglion cells is lessened. This is especially the case with nerve fibres. The cervical sympathetic may be left for a minute or two in a pool of 1 per cent. nicotin sulphate,* and still on stimulation cause maximum dilation of the pupil. The superior cervical ganglion requires a freer application of 1 per cent. nicotin sulphate than of 1 per cent. nicotin to paralyse it, but the paralysis is still readily produced. The period of paralysis, after painting the superior cervical ganglion with | per cent. nicotin, passes off in twenty to thirty minutes, so that in no long time the sympathetic in the neck produces its usual effects. To paralyse the ganglion a second time requires a very much larger dose of nicotin than was required the first time. Painting it over with even 0°5 per cent. nicotin without any excess of fluid may be sufficient the first time, but painting the ganglion half-a-dozen times with 1 per cent. nicotin may be required to paralyse it a second time. We had hardly expected to find so marked an example of the habituation to poisons which is known to occur in certain cases, and especially with nicotin. Apparently also the period of paralysis lasts a shorter time after the second application of nicotin than after the first. As arule, the application of nicotin to the ganglion causes for a brief period the same effect as stimulating the nerve. The alkaloid appears to excite the nerve cells before paralysing them. * For convenience we speak of the neutralised solution containing 1 per cent. nicotin as a 1 per cent. nicotin sulphate solutiun. It contained, of course, a rather higher percentage of the sulphate. 1889.] On the local Parulysis of Peripheral Ganglia, &c. 427 Ganglion of the Solar Plexus. In the dog, cat, and rabbit the splanchnic nerve on the left side runs to two chief ganglionic masses. Since the upper of these ganglia sends its nerves chiefly to the cceliac axis and the lower sends its nerves chiefly to the superior mesenteric artery, we may call these respectively the cosliac and superior mesenteric ganglia. From the solar plexus nerve fibres run to the kidney. Usually these are joined by fibres direct from the splanchnic. In the cat and dog there has been in the cases we have examined a lesser splanchnic, running partly to the renal plexus and partly to the solar plexus. The renal ganglia are, as is well known, scattered, but in the dog the chief one often lies underneath the supra-renal body, and in the cat the chief one is placed between the artery and vein on fibres proceeding chiefly from the superior mesenteric ganglion and about 4 inch from it. Our experiments upon the connexion of the splanchnic with the ganglia of the solar and renal plexus have been made almost entirely on the left side, and in the following account we speak of the nerve and ganglia of the left side, unless the right side is especially men- tioned. When the stomach and intestine are exposed there are usually slight movements of the intestines, and there may be movements of the stomach. When these are absent they may be brought about, with a degree of distinctness varying with the animal, by stimulating the vagus. These movements continue for a short time after the nerve stimulation has ceased. Stimulation of the splanchnic stops the movements, whether they are spontaneous or are occurring as the result of previous vagus stimulation. These facts are well known; but whether the inhibitory fibres of the splanchnic end in the nerve cells of the solar plexus has so far been guess work. ‘T'o determine this we have proceeded as in the case of the superior cervical ganglion. Having ascertained that the application of 1 per cent. nicotin or nicotin sulphate to the splanchnic leaves its inhibitory power unaffected, we have painted one or other of the ganglia, or the whole plexus, with a small brush moistened with 1 per cent. nicotin or nicotin sulphate. Nicotin applied to the whole plexus at once abolishes the inhibitory power of the splanchnic, but inhibition, although naturally much less perfect, can still be produced by stimulating the fibres proceeding from the ganglia. Hence the inhibitory fibres of the splanchnic end in the cells of the solar plecus. Further, if the superior mesenteric ganglion be brushed over with nicotin, stimulation of the splanchnic is still able to produce inhibition of the movements of the stomach, but is without any appreciable effect upon the movements of the intestine. On the other hand, when nicotin is applied to the cceliac ganglion, the inhibitory power of the splanchnic upon the intes- 428 Messrs. J. N. Langley and W. Lee Dickinson, [Nov. 21, tines is not abolished, but that upon the movements of the stomach in the main at any rate is abolished. Our experiments are not sufficiently numerous, especially with regard to the connexion of the cceliac ganglion with the stomach, to make it certain that the one ganglion is entirely connected with the fibres to the intestine, and the other the fibres to the stomach, but we think they show that an the main, and possibly altogether, the stomachic inhibitory fibres of the splanchnic nerve end in the cells of the celiac ganglion, and the intestinal inhibitory fibres of the splanchnic end in the cells of the swperior mesenteric ganglion. The vagus is said to send fibres to the ganglia of the solar plexus. We find, however, that copious application of nicotin to the plexus on both right and left sides of the body does not interfere with the move- ments of the stomach and intestines produced by stimulating the vagus in the neck: that is to say, the motor fibres of the vagus do not end in the nerve cells of the solar plexus. We may note that after nicotin has been applied to the ganglia of the solar plexus the spontaneous movements of the intestine become more pronounced ; that the ganglia recover in twenty to thirty minutes from their state of paralysis; and that to produce paralysis a second time a larger amount of nicotin is required. The connexion of the vaso-motor fibres of the splanchnic with the nerve cells of the solar plexus can be determined by taking a tracing of the arterial blood pressure and stimulating the splanchnic before and after the application of nicotin to the ganglia. In the rabbit and cat, brushing either the coeliac or the superior mesenteric ganglion with 1 per cent. nicotin sulphate diminishes the effect of stimulating the splanchnic. The rise of blood pressure produced is much less than previous to the application of nicotin. By applying nicotin to both ganglia, being careful not to allow any to reach the renal plexus, the rise of blood pressure caused by stimulating the splanchnic is reduced to very small limits—in the rabbit, indeed, there may be no rise of blood pressure—and, by applying it to the renal plexus as well, the effect of splanchnic stimulation on the blood pressure is abolished. We have obtained some evidence that, as in the case of the inhibitory splanchnic fibres, so the vaso-motor splanchnic fibres for the area of distribution of the cceliac artery run to the cceliac ganglion, and those for the area of distribution of the superior mesenteric artery run to the superior mesenteric ganglion; but the method of deter- mining this, viz., by observing the state of pallor of the viscera, often gives unsatisfactcry results. Bradford has recently shown that vaso-dilator fibres run in the splanchnics to the kidney, and probably to the stomach and small intestines. We find that after nicotin has been applied to the ganglia of the solar and renal plexuses stimulation of the splanchnics causes 1889.] On the local Paralysis of Peripheral Ganglia, §c. 429 no fall of blood pressure. We conclude that the vaso-dilator as well as the vaso-constrictor fibres of the splanchnic end in the cells of the solar and renal plexuses. The connexion of the renal fibres with nerve cells, although it can to a certain extent be deduced from observations like those we have just given, is most satisfactorily made out by noting directly the volume of the kidney with the aid of Roy’s oncometer. We have so far only made this observation on the dog. In the dog copious appli- cation of nicotin 1 per cent. to the ganglia of the solar plexus does not prevent stimulation of the splanchnic from causing a normal large constriction of the vessels of the kidney. This constriction, in the few experiments we have made, has been as great as that occurring before the application of nicotin to the solar plexus. On the assump- tion that the constriction would be less if some of the vaso-constrictor fibres had been put out of action, we conclude that few if any of the splanchnic vaso-constrictor fibres for the kidney end in the ganglia of the solar plexus. On separating the supra-renal capsule from the underlying tissue, and applying nicotin to the ganglia which lie underneath its lateral part, a decrease in the effect of splanchnic stimulation occurs, and on brushing nicotin on the artery near the supra-renal capsule there is a still further decrease inthe effect. Since the dogs on which we have experimented have had much fatty tissue around the artery and vein, we have not succeeded in laying bare the whole of the renal plexus without some mishap, and to this we attribute the fact that in the dog we have not obtained by the application of nicotin a complete abolition of the vaso-constrictor power of the splanchnic upon the kidney. Combining, however, the oncometer observations on the dog with the blood pressure observa- tions on the rabbit and cat, we think there is fair evidence that the splanchnic vaso-motor fibres for the kidney end wm the cells of the renal plexus. The immediate effect of the application of nicotin to the ganglia of the solar plexus is a rise of blood pressure and a dilation of the kidney, followed by a fall of blood pressure and a constriction of the kidney. The application of nicotin to the ganglia of the renal plexus causes a constriction of the kidney followed by a dilation, both being greater than when nicotin is applied to the solar plexus, and with a comparatively small effect on the blood pressure. Whilst normally stimulation of the splanchnic in most cases causes a slight primary dilation of the kidney, corresponding with the rise in blood pressure from constriction of vessels of the stomach or intestine, after nicotin has been given we have in no case observed a primary dilation of the kidney or stimulation of the splanchnic. We have experimented upon various peripheral ganglia other than those mentioned above, and, though our results are as yet incomplete, 430 Local Paralysis of the Peripheral Ganglia, §¢. [Nov. 21, with essentially similar results: that is, we have obtained an abolition of the effect of some one or more of the classes of netve fibres running to them. We think then there is fair ground to conclude that by stimulating the nerve fibres running to and those from any peripheral ganglion, before and after the application of dilute nicotin to it, the class of nerve fibres which end in the nerve cells of the ganglion can be dis- tinguished from those which run through the ganglion without being connected with nerve cells. There are various other questions suggested by the action of nicotin which we hope to deal with later.—Does the paralysis of the ganglion on the posterior root prevent the passage of a stimulus to the central nervous system? Are all afferent fibres connected with nerve cells in the posterior root, or do some run through the ganglion or end else- where? Can centres be isolated, or the connexions of tracts followed in the brain and spinal cord ? Does any poison when locally applied to ganglia affect unequally the cells in which the different Claes of. fibres end ? We append an account of an experiment upon the splanchnic to illustrate the method employed. . Rabbit—5 mgrms. morphia hydrochlorate injected subcutaneously. Chloro- form. Cannula in carotid artery for kymographic tracing. Left splanchnic nerve dissected out for 1% inch, ligatured, and cut. Peristalsis good. Secondary coil at 7 cm.; this gives a current fairly strong to tip of tongue. Originally, and as a rule after each application of nicotin-sulph. to the nerve or ganglia, the splanchnic was stimulated three times at interva!s of a minute: since the effect of each of the three stimulations was the same, we mention below one only. 1.18 p.m. Stim. splanchnic for 30 sec. Blood pressure rose rapidly after 2 sec. stim., in 4 sec. rising from 70 to 90 mm. Hg, where it remained for rest of stim., sinking gradually afterwards and regaining previous level in 14 min. Peristalsis of intestines inhibited. 1.21 ,, Splanchnic painted nearly up to the solar plexus with nicotin sulph. 1 per cent. The nicotin was freely applied several times, a small piece of sponge being placed under the nerve close to the solar plexus to prevent the alkaloid from reaching the ganglia. 1.26 ,, Stim. splanchnic for 15 sec. Blood pressure rose in same manner from 62 to 80 mm. Hg. Peristalsis of intestines inhibited. 1.30 ,, Ccliac ganglion painted with nicotin sulph. with a small brush, a portion of superior mesenteric ganylion also being touched. © 1.83 ,, Stim. splanchnic for 15 sec. Blood pressure rose in same manner from 72 to 80 mm. Hg. Peristalsis of intestines inhibited, but apparently less readily. 1.35 ,, Nicotin sulph. applied to whole region of solar qs no excess of fluid being used. 1.40 ,, Stim. splanchnic for 45 sec. Blood pressure remained at same level, 68 mm. Hg. Peristalsis of intestines not inhibited. 2.53 ,, Stim. splanchnic for 15 sec. Blood pressure rose in same manner as at first, rapidly from 58 to 79, and subsequently to 86 mm. Hg. Peristalsis of intestines inhibited. Thus, in half an hour the paralysis of the ganglia had disappeared. 1889. | Tubercles on the Roots of Leguminous Plants. — 431 2.6 P.M. Whole region of solar plexus painted with nicotin sulph. 2.10 ,, Stim. splanchnic for 45 sec. Blood pressure remained at same level, 60 mm. Hg. In the tracing there were no respiratory variations, but at intervals of 25 to 30 sec. there was a slight fall of the blood pressure. IV. “On the Tubercles on the Roots of Leguminous Plants, with special reference to the Pea and the Bean,” By H. MARSHALL WARD, M.A., F.R.S., F.L.S., late Fellow of Christ’s College, Cambridge, Professor of Botany in the Forestry School, Royal Indian Engineering College, Cooper’s Hill. Received October 22, 188%. (Preliminary Paper.) In the ‘ Philosophical Transactions’ for 1887 (vol. 178, B, pp. 939—562, Pl. 32 and 33) I published the results of some investiga- tions into the structure and nature of the tubercular swellings on the roots of Vicia faba, the broad-bean of our gardens, paying attention to the bearing of the facts on other Leguminous plants, and discussing what had been done and written at various times concerning these curious structures. The chief facts established in that paper were as follows :—That the tubercles occur in all places and at all times on the roots of Papilionaceous plants growing in the open land, but that in sterilised media and in properly conducted water-cultures they are not deve- Joped, unless the root is previously infected by contact with the contents of other tubercles. In other words, the tubercles can be produced at will by artificial infection. I also showed that the act of infection is a perfectly definite one, and is due to the entrance into the root-hair of a hypha-like infecting tube or filament, which starts from a mere brilliant dot at the side or apex of the root-hair, passes down the cavity of the latter, traverses the cortex of the root frora cell to cell, until its tip reaches the innermost cells of the cortex, where it branches and stimulates these cells to divide and form the young tubercle. It should be noted that these fruits of the infection were entirely new, as were the methods, and that I showed actual preparations of the infecting filaments passing down the root-hairs, to several botanists at the time (June, 1887). In my paper were also explanations of several points hitherto obscure—such as the curious trumpet-shaped enlargements of the filaments where they transverse the cell-walls of the tissues, suggest- ing that they were due to subsequent stretching of the walls of the meristematic cells. Also the peculiar haustorium-like swellings of VOL. XLVI. 26 432 , Prof. M. Ward. On the [Nov. 21, intra-cellular filaments, and the minute “ bacteroids” (which I termed “‘oemmules””) were described. Again, I called attention to the re- markable coiling and distortion of the root-hairs at the point of origin and entry of the infecting filament. It may be recalled to mind that I wrote of the minute brilliant dot at this spot ‘‘ unless this dot is one of the above-named ‘germs’ (1.e., a ‘ bacteroid’ or ‘gemmule’) I do not know what it can be” (p. 548). I also distinctly pointed out that the twisting of the root-hair at the point of infection might be due to the wall of the root-hair growing elsewhere, but not at that point. As to the “gemmules” or “bacteroids”* with which the cells of the inner parts of the tubercle are filled, and their relations to the filaments, I expressed myself (somewhat cautiously it is true) to the following effect. From their curious shapes—those of the letters V, Y, and X, and even more branched figures—I suggested that these bodies propagate by budding; and from their relations to the swollen ends of the intra-cellular branches of the filaments it was not improbable that they are budded off from these, and multiply by further budding in the protoplasm, &c., of the cells. Owing to the extreme minuteness and high refractive index of these bodies, how- ever, I could not definitely decide as to the method of propagation ; although no doubt existed that they are living “‘ germs,” on the one hand, and that they originate from the filaments, on the other. I also pointed out that their presence in the protoplasm of the cell stimulates the latter and makes it resemble a plasmodium (p. 547). Other points of importance will be recalled as we proceed. IT have now to draw attention to some results of my further researches into this confessedly difficult subject. After numerous culture experiments and observations made last year (1888), I have decided to abandon the broad-bean as the subject for histological analysis, chicfly becatse it takes so long to exhaust its stores of reserve materials; it was better for the cultures to be made with the pea, the cotyledons of which are so much smaller, and the’ plant of which is more easily managed in every way in water- and pot-cultures. On the other hand, the tubercles and their contents present no essential features of difference, and, indeed, I may say at the outset, that all that has been described with respect to the tuber- cles of the one is essentially true for those of the other. The position ou the roots and the sizes and shapes of the tubercles are the same, and they appear under the same conditions. The colour and general structure of their internal tissues are similar, and the bacteroids of the pea are so little different from those of the bean that it is difficult to believe them specifically distinct. But I can offer more conclusive evidence than the above for the * Tschirch’s word “ bacteroids” is a very convenient one, as it does not commit us to any statement as to the nature of these bodies. 1889.] Tubercles on the Roots of Leguminous Plants. 433 identity of the bacteroids in the two cases. In some of the cultures made in the summer of 1888 I infected the roots of the pea with bacte- roids taken from the tubercles of the bean, and as this is a point of some importance, in view of the belief that each species of Legu- minose may have its ownspecies of bacteroid, I may say a few words on this phenomenon. Having satisfied myself that when the contents of the tubercles of the bean are placed among the root-hairs of the young bean root, the latter become infected, I prepared a number of beans and peas as follows: They were allowed to germinate in the sterilised sand until the radicle was about half an inch long; each seedling was then pinned to a cork, and so fixed that the radicle pointed downwards into a large wide-mouthed bottle, in which the cork fitted. The bottle was then carefully lined with filter-paper, kept moist by dis- tilled water; the cork fitted closely, and thus the atmosphere in the bottle was sufficiently damp to enable the radicle to go on growing at the expense of the reserve materials in the cotyledons, and in course of time to put forth a dense pile of delicate root-hairs. As each seedling was pinned on to the cork, I sprayed on to the surface of the radicle, by means of a freshly-drawn capillary tube, a mixture of bacteroids and water made as follows: Tubercles of the bean-roots were carefully washed, placed in alcohol for a few minutes, and then fired, then again washed with distilled water, and pounded in a mortar with distilled water: small drops of this were placed on the radicles as said—z.e., on the radicles of both peas and beans. In other cases I employed the hanging drops in which I was attempting to cultivate the bacteroids. These consisted of nutritive solutions with asparagin, and with or without gelatine, and in which were placed a few of the bacteroids obtained from cleaned tubercles (cut with a razor sterilised by heat) by means of sterilised needles. I may here say that these cultures (7.e., as micro-cultures) have given me much trouble, and little results: to obtain pure cultures is a matter of greater difficulty than Beyerinck’s paper would lead one to expect, and it is not proposed at present to Jay much stress on the evidence got from them. Nevertheless, colonies are obtained, and in some cases at least I have transferred the infecting organism from these cultures to the root-hairs of peas and beans. In any case, I have succeeded in obtaining extracts of the tubercles which contain the infecting germs, and although the latter were always taken from the tubercles of the bean, they infected the root- hairs of both peas and beans equally well. It is especially the very young root-hairs, with extremely delicate cell-walls, that are infected, and the first sign is the appearance of a very brilliant colourless spot 7m the substance of the cell-wall (figs. A and B): sometimes it is common to two cell-walls of root-hairs in 2G 2 ———— a _ -= ee ne ee a ee ee ee ee ek ee er sr re . rm oat a i ¥ 434 Prof. M. Ward. On the IN ov aay contact, and not unfrequently one finds several root-hairs all fastened together at the common point of infection (fig. B). This highly _ refringent spot is obviously the “bright spot” referred to in my pre- ee Root-hairs of the pea in process of being infected. A, two very young hairs with the germ in the cellulose wall ; B, three root-hairs in the same condition. In C the infecting tube has commenced to grow down the root-hair. The latter is dis- torted at the point of origin of the tube. The beginning of the distortion is appa- rent in A (the left-hand figure). A and C = Zeiss J.imm.; B = E obj. vious paper as the point of infection from which the infecting filament takes origin. It soon grows larger, and develops a long tubular process (fig. C), which grows down inside the root-hair, and invades the cortex, passing across from cell to cell, as described in 1887. As a matter of fact, then, the ‘‘ bright spot” is the point of origin of the infecting filament; and, as a matter of inference from the experiments, it cannot but be developed from one of the ‘‘ bacteroids” or “gemmoules” of the tubercles. This attaches itself to the root- hair, fuses with and pierces the delicate cellulose wali, and grows out 1889.] Tubercles on the Roots of Leguminous Plants. 435 into a hypha-like filament at the expense of the cell-contents. The - further progress of this filament has already been described in my memoir in the ‘ Philosophical Transactions’ for 1887. Before proceeding further, reference may be made to some re- searches made during 1888 and 1889 with the object of learning more about the conditions which rule the development of the tubercles, and the relations of the organism to them. At first I set myself the task of trying to discover a definite spore-stage, thinking that in the rotting tubercles, or at the period of maturity of the plant, or at some other time, it might be that the parasite would betray itself and develop spores: this is not the case apparently, for my experiments seem to prove conclusively that the well-being of the organism of the ‘tubercle and that of the pea or bean go hand in hand. This of course is only so much evidence in favour of the view that we have here a case of symbiosis of the closest kind, as expressed in my previous memoir. One remark is necessary here. My object throughout had been more especially to determine the nature of the tubercles and of the organism which infests them: the further and larger question as to their function or influence in the economy of the Leguminous plant has been kept subordinate for the present, because I am convinced that more time and appliances are necessary for its complete solution than are at my disposal at present. At the same time some of the following results ought to help in solving the problem as to the possible relations of the tubercle organism to the acquirement of nitrogen by the higher plant. | During the spring and summer of 1888 I made numerous experi- ments with water-cultures with beans, allowed to germinate in soil so as to be infected by the ‘‘ germs” therein as demonstrated previously. Several dozens of such cultures were made, and some of them placed in the dark, others in the ordinary light of the laboratory, and some in a well-lighted greenhouse. Tables were prepared showing the number of leaves, living and dead, the condition of the roots, the height of the stem, and so forth, as recorded every week or so (or at shorter intervals) when I examined the plants. It resulted that when the beans are in any way so interfered with that they do not assimi- late more material than is necessary for the growth and immediate requirements of the plant, the infecting organism either gains no hold at all on the roots, or it forms only small tubercles which are found to be very poor in “ bacteroids:” in some cases the starving plants began to develop tubercles, which never became larger, and in which the infecting organism seemed to be in abeyance. Whether this is due to the bacteroids being developed in small quantities, or to their absorption into the plant is still a question. I hardened many of these tubercles in picric acid, stained them, 436 Prof M. Ward. On the ‘[Nov. 21, and cut sections, comparing the results with similarly prepared — normal tubercles: the chief difference was the paucity in bacteroids, and the prominence of the branched filaments in the cells. Similar results were obtained by placing a box over beans growing in the garden, and comparing the tubercles of the etiolated plants with those of normal plants beside them. In the spring of this year (1889) I started a series of water-cultures of beans, infected artificially by placing the contents of tubercles on their root-hairs, and kept the roots oxygenated by passing a stream of air through the culture liquid for 24 hours at intervals of a few days: here again the increased growth of the plants—not compen- sated by increased assimilation—seemed to cause the suppression of the tubercles, or the formation of very poor ones only. These experi- ments, carried out on several dozens of plants, lead me to conclude that the organism which induces the development of the tubercies is sc closely adapted to its conditions that comparatively slight disturb- ances of the conditions of symbiosis affect its well-being: it is so dependent on the roots of the Leguminose, that anything which affects their well-being affects it also. Some experiments with peas, which are now being tabulated, may throw some light on the wider question which has been raised of late, as to the alleged connection between the development of these tuber- cles and the increase of nitrogen in Leguminous plants. Thirty-two peas were sown in separate pots of silver-sand, or soil, in five batches of six each, and one of two, and treated in various ways. Six were in garden soil; six in silver-sand, with culture salts, including a nitrate; six in the same medium without nitrate; six in the sand, with traces of soil washings or- with pieces of tubercles added ; six in sand sterilised by heating ; and two in sterilised sand, to which salts (including nitrogen) were added. All but those in the thoroughly sterilised medium bore crops; and these crops have been analysed for me by Professor Green. The soils, water, and other parts are being analysed by Dr. Matthews of Cooper’s Hill. I have to thank these gentlemen for the great care and trouble they have kindly taken in this matter. . My object was to decide, if possible, certain points as to the effects of such treatment on the development of the tubercles; but the experiment may possibly turn out more instructive than was at first thought, and will at any rate suggest a line of inquiry to be followed out in the coming spring and summer. With respect to these plants, I may say that I shall have data show- ing how much nitrogen was present in the medium at the beginning of the experiment; how much was added; how much the average seedling pea contained; and how much the crop contained in each case. The condition of each plant at convenient intervals was 1889.] Tubercles on the Roots of Leguminous Plants. 437 recorded ; the number of living leaves and of dead ones; the height of the stem; number of buds, flowers, and fruits, open and set; and the number i seeds ripened. The tubercles were developed on all but one of the plants, except those in the completely sterilised media. However, I do not propose to go further into these matters at present, simply contenting myself with pointing out that all the evidence at present goes to show that the Leguminous plant gains witrogen by absorbing the nitrogen sus substance of the bacteroids from the tubercles; that nitrogenous sub- stances are thus brought by the “ bacteroids” (‘“‘gemmules”’) of the infecting organism of the plant; and that, finally, no satisfactory explanation seems forthcoming as to how the organism obtains this nitrogen in certain cases where no compounds of nitrogen have been added. At any rate, if we regard the pot of sand and its pea as one system, there is in some cases a distinct gain of nitrogen in the crop, and in the sand at its roots. Since the publication of my paper in 1887, cael observers have attacked the subject from various points of view. The most import- ant papers are those of Vuillemin,* Beyerinck,+ and Prazmowski,t who deal with the histology and biology of the subject; and those of Hellriegel and Wilfarth, and of Lawes and Gilbert,§ who have con- cerned themselves especially with the nitrogen question; papers on accessory matters by Frank, Van Tieghem, and a few others have _also appeared in the interval. I propose to deal at present only with Prazmowski’s papers, since there are several points in them that have special reference to my work ou this subject. In the ‘ Botanisches Centralblatt’ for 1888,|| appeared a paper by Prazmowski, on the ‘“ Root-tubercles of the Leguminose.” After shortly summarising the literature, and the various views promul- gated by different investigators as to the nature of the swellings, the author proceeds to give an account of his own researches. He gives me the credit of havmg taken a new departure; speaking critically of the want of experimental proofs for their speculative views on the part of previous observers, he says, ‘‘ Hine ruhmliche Ausnahme biidet in dieser Beztehung Marshall Ward, welcher zuerst in den Weg des phystologischen Experimentes betreten hat” (p. 217), though he does not regard my methods as complete. * “Tes Tubercules Radicaux des Légumineuses,”’ ‘ Annales de la Science Agro- nomique francaise et étrangére,’ vol. 1, 1888. + ‘Botanische Zeitung,’ 1888, No. 46, p. 725. t ‘ Botanisches Centralblatt,’ 1888, No. 46, pp. 215—285 ; and 1889, No. 38, p. 356. § ‘Phil. Trans.,’ vol. 180, 1889, B, pp. 1—107. || No. 46, pp. 215--285. The paper is an abstract of an address to the Polish Naturalists’ Congress, July, 1888. 438 Prof. M. Ward. On the | Nomina, Experiments with peas and kidney beans enabled him to confirm decisively the discovery that plants in sterilised media, watered with boiled water, develop no tubercles on their roots, whereas those in ordinary soil, or in sterilised media to which infective matter from open soil or from tubercles was added, alwaysformed them. In other words, the tubercles arise by infection from without, as I had demon- strated. He then proved that very young tubercles still show the infecting filaments passing down the root-hairs, ‘ gewohnlichen Pilzhyphen nacht unahnliche Faden, welche, Wurzelhaare und Epidermis durchwachsend, in das subepidermale Gewebe der Wurzel eindringen. Diese Faden hat schon Marshall Ward in den Wurzelhaaren der Bohne (Vicia faba) beobachtet und auf Grund dieser Beobachtung behauptet, dass die fraglichen Knollchenorganismen durch Wurzelhaare in die Wurzel emmdringen.” He describes the appearance of the filaments, their bright look, apparent want of membrane at first, granular contents, &c., all in accordance with my statements in 1887. The granular contents gave him much concern; they are seen as minute rodlets under certain reactions. The branching, piercing of cell-walls, &c., are described as by myself. The only difference here is that Prazmowski believes the rodlets to be the same as the bacteroids. He completely confirms my observation that the tubercle arises from disturbances produced in the deeper cortical tissues by the infecting filament, and describes the cell-contents, nucleus, &c., so well known. He also points out that in the very young conditions, the bacteroids are simple rodlets, even in cases where they become V, Y, X, &e., shaped later. To sum up, Prat#mowski’s account of the whole matter confirms that which I gave to the Royal Society in 1887, excepting that he interprets the origin and nature of the bacteroids differently; he regards them as produced from the contents of the filaments—as germ-like bodies developed in the interior of the filaments, and not budded off from them. This is hypothesis only, however, for the author expressly states (p. 253), “ Direct habe ich thre Theilungen nicht gesehen, obgleich ich mir die Muhe gab, ste in den verschiedensten Nahrmedien und unter den verschiedensten dusseren Bedingungen zu ziuchten.”’ He concludes they can only multiply in the still living protoplasm. As to the shapes of the bacteroids and tubercles, Prazmowski’s statements agree with those of previous observers, and he also remarks the plasmodium-like appearance of the cell protoplasm at certain stages, as noticed by mygelf. Some observations on a possible spore formation need not be dwelt upon, as he recognised his mistake in a subsequent paper in 1889. He leaves the question as to the origin of the bacteroids by budding or otherwise quite undecided, having failed to satisfy himself whether 1889. | Tubercles on the Roots of Leguminous Plants. 439 my suggestion is right or not; at the same time he fully agrees with me and others in believing that these tiny bodies must be the infecting agents, easily and abundantly distributed as they are in the soil, water, &ce. In the ‘Botanisches Centralblatt,’ vol. 39, No. 12, 1889, p. 356,* is a second paper by Prazmowski, on the nature and biological signifi- cance of the root tubercles of the pea, in which he sums up his views so far. He says, the root tubercles of the Papilionaceze are not normal structures, but are caused by a special fungus, which inhabits the tubercles, and the spores of which must also occur in the soil. Hitherto he had been unable to determine the true nature of this fungus, but only to show that it penetrates through the root-hairs into the young root, grows in it in the form of more or less branched, unseptate tubes, which are clothed by a dense refringent membrane and contain innumerable extremely minute rod-like bodies. Under the influence of this fungus the young tubercle is developed in the deeper parts of the cortex, and in its tissues the bacterium-like contents of the fungus become distributed, and grow, divide, and branch at the expense of the protoplasmic contents. He regarded the phenomenon as one of symbiosis, and as benefiting the host as well as the parasite. Prazmowski then refers to the papers by Vuillemin, Beyerinck, Hellriegel, and Wilfarth, and says that these instigated him to take up the matter again, and to confine his attention to the pea. The summary of his new results runs as follows :— The tubercles are not formed in sterilised media unless infected. The infecting organisms are bacteria, identical in form and pro- perties with those cultivated by Beyerinck from the tubercles of various species. From young tubercles the bacteria can be obtained and cultivated pure, and infections from the cultures cause the tubercles to develop. The development of the tubercles is only possible in young roots or rootlets ; infection does not occur in older portions of the root system. The tubercle-bacteria penetrate through young (not suberised) cell membranes into the root-hairs and epidermis cells of the root, and there multiply at the expense of the protoplasmic cell-contents. Their further development has so far been observed only in root-hairs. _ After accumulating and multiplying in the root-hair, they unite in racemose colonies at or near its apex; these colonies become denser and closer, surround themselves with a resistent bright membrane, and join by its means the cell-membrane of the root-hair. Thus arises ab the apex of a hair, and on its inner side, a bright knob, usually surrounded by free colonies of bacteria—+t.e., colonies not * This paper is quoted from the ‘ Berichte a.d. Sitzungen der K. K. Akad. d Wiss. in Krakau,’ June, 1889, and it appears in several journals in the same form. 440 3 Prof. M. Ward. On the [Nov. 21, enveloped by membrane. The top of the root-hair coils round the knob, and the latter then puts forth a tube filled with bacteria and . surrounded by a brilliant membrane. From this stage onwards, till the tubercle is developed, this tube behaves like a hypha, growing at the apex, and putting out beanies beneath the apex which behave like the original filament. The tube now grows from the root-hair, through the cortex, and even as far as the endodermis, boring through the walls of the cortex cells, splitting them mostly into two lamelle, so that a swelling full of bacteria and bounded by lamelle is formed. In the cells the tube grows towards the nucleus, and usually applies itself so close that the latter is indistinguishable unless stained. Hence, probably, the reason why Beyerinck regarded the tube as “‘schleim”’ débris remain- ing over from nuclear division. So far, we have no free bacteria in cells ; they are all in the tube. As soon as the tube reaches the deeper layers of the cortex the cells begin to divide, at first slowly and irregularly, then quickly ; and this is especially true of the four or five innermost layers of the cortex. Then also numerous thin branches are developed from the tubes, enter the new cells, and branch in them. The result is the meristem of the tubercle. The middle of the tubercle consists of a parenchyma of larger cells, penetrated by tubes in all planes, and filled later with bacteria freed from the dissolving tubes; the outer layers consist of smaller and more flattened cells with poorer contents, the membranes of which are suberised later. Between the bacteroid tissue and the latter (cortex of tubercle) is a small-celled meristem, free of bac- teroids; this produces vascular bundles further back, and these fork — and are joined to those of the root. Between the vascular bundles and the bacteroid tissue is further a layer of starch-bearing cells, ange of bacteria. The place where the tubercle forms is predetermined by the infect- ing tube, and since this enters anywhere, the tubercles arise irregularly, i.€., opposite or not to xylem or phloém. Pericambium has nothing to do with it, and so Van Tieghem, Beyerinck, and others are wrong in regarding these tubercles as modified lateral roots. After the tissues of the tubercle are differentiated and the bacteria are set free (parts of the tubes do not burst and dissolve), the latter fuse with protoplasm, multiply by growth and fission, become forked, and subsequently form the bacteroids. The further fate of these depends on their réle in the economy of the plant. As did Hellriegel, so also Prazmowski put some plants in soils with, others in soils without, nitrogen, and he confirms Hellriegel’s results—infected plants require no nitrogen at their roots; non- infected plants pass into a state of hunger and die if not supplied with nitrates. 1889.] Tubercles on the Roots of Leguminous Plants. 441 _ No decision is arrived at as to whether the nitrogen is got from nitrogen compounds or from the free nitrogen of the air, nor as to what advantage accrues to the bacteria and the host-plant respec- tively. As regards the plants’ mode of utilising the presence of the bacteria, cultivated bacteria (from pea tubercles) in nutritive media divide indefinitely, and are found there as moving rodlets. In tubercles they are only rodlets while enclosed in tubes; they change their forms in the substance of the protoplasm, becoming forked and developing into bacteroids. As bacteroids they can long go on multiplying by continually developing lateral branches, even in proper nutritive solu- tion (‘‘In diesem Zustande der Bakteroiden konnen sre sich noch eine Zeit lang vermehren unter fortwahrender Bildung von Seitenzweigen selbst dann, wenn sie aus dem Knéllchen heraus, in geeignete Nahrlésung versetzt werden”). With the further development of the tubercle they become hyaline, cease to multiply, and at length dissolve. The contents of the bacteroid cells are resorbed as the bacteroids dissolve, certain substances being left behind. In other words, the plant utilises the substance of the bacteria. When emptying begins, and with what energy it proceeds, depend especially on the quantity of nitrogenous compounds at the disposal of the roots. In a soil rich in nitrogen the tubercles go on developing unhindered, become large and typical, and rosy inside, and are not exhausted till late ; in poorer soils they attain no great size, are soon emptied, and are green-gray inside. In both cases the exhaustion proceeds acropetally, from the base onwards. At the apex remains a zone which is not emptied, and its cells are full of bacteria. Moreover, some bacteria in and out of tubes remain in all the cells, and escape during decay into the soil; also animals eat the tubercles and disperse the bacteria. In such injured tubercles the bacteroid masses often envelop themselves anew with membranes, and form smaller and smaller colonies; these the author previously mistook for spores (see p. 438). From the preceding, we see that the tubercles depend on a symbiosis which is advantageous to both the plant and the bacteria. The latter feed on the sap and cell-contents, and multiply through innumerable generations, and, both during the life of the host and ‘afterwards, become redistributed in the soil. The plant derives advantage in that it obtains nitrogen by means of the bacteria. Though the symbiosis is useful to both, the plant gains most, for it is the more powerful, and sooner or later overcomes the bacteria, to the multiplication of which it sets limits and finally absorbs the substance of the latter. Being the stronger, the plant directs the symbiosis. It encloses the bacteria in the “ Bakteroidengewebe,” by means of cork, and also protects them. By an apical meristem the 442 Tubercles on the Koots of Leguminous Plants. [Nov. 21, tubercle provides continual successions of new cells for the bacteria to accumulate in while it absorbs the older ones behind. Between the bacteroid tissue and the cork it provides vascular bundles (1) to feed the bacteria and convey the carbohydrates necessary to produce proteids, and (2) to take up the dissolved substance of the bacteroids as required. The thin cell walls of the bacteroid tissue conduce to the same end. I think it will be admitted by all who study the literature of this subject, that the only real point at issue between Prazmowski and myself is the nature of the bacteroids and their origin from the filaments. I interpreted them as extremely minute budding “gem- mules,” and not bacteria; Prazmowski, with Beyerinck, regards them as true Schizomycetes. We have all alike failed to actually see the process of budding or fission, a fact which will surprise no one who has examined these extremely minute bodies, which are, as Beyerinck rightly puts it, among the smallest of living beings. The fact of infection, and the mode of infection, by means of a hypha-like filament passing down the root-hair were definitely estab- lished by myself in 1887, and it is satisfactory to find it confirmed in every essential detail by Prazmowski. Our views as to the symbiosis, the struggle between the protoplasm and the “gemmules” (or “bacteroids”) are the same: though Prazmowski and Beyerinck carry the matter a step further in definitely inferring the absorption of the conquered bodies of the latter, a point in part supported by some of my experiments. As to the occurrence, origin, and structure of the tubercles, Prazmowski’s account is simply in accordance with my own; and it is interesting to note how many points of detail—the distortions of the root-hairs, the relations of the branching filaments to the nuclei and cell-contents, and those of the incipient tubercle to the end of the filament, for example—are confirmed by him. There is one point of extreme importance between Beyerinck and Prazmowski on the one hand, however, and myself on the other; they are positive on the subject of the cultivation of the “ bacterium ” in nutritive media outside the host-plant—or rather the other symbiont—whereas I feel too little confidence in my cultures to assert that the “ germ” is definitely isolated and: recognised. Ht is true, I have obtained colonies in the cultures which may be those referred to by these writers, and I may remark that so long ago as 1887 I wrote that certain flocculent clouds in my cultures may be colonies of the organism in question, as I obtain similar clouds of multiplying ‘‘ germs” on the root-hairs of my water-cultures. More- over, in some cases I have clear proof that among the colonies in my cultivations the germ in question existed, because I infected peas and beans with them; but it would be going further than the facts 1889. |] Presents. 443 warrant to claim to have definitely isolated and recognised the ‘““oerm” by its morphological characters. Still, enough has’ been done to enable us to say with some confidence that this will yet be done, even if we do not accept that Prazmowski and Beyerinck have already done it. Presents, November 21, 1889. Transactions. Baltimore :—Johns Hopkins University. Studies in Historical and Political Science. Seventh Series. Nos. 7-12. 8vo. Bal- timore 1889; Annual Report, 1889. 8vo. Baltimore; Register for 1888-82. 8vo. Baltimore 1889. With Seven Dissertations presented 1888-89. 8vo. Baltimore. The University. Berlin :—K. Preussiche Akademie der Wissenschaften. Abhand- lungen. 1888. 4to. Berlin 1889. The Academy. Physikalische Gesellschaft. Verhandlungen. 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South African Butterflies. 3 vols. 8vo. London 1887-89. Mr. Trimen. Wood-Mason (J.) A Catalogue of the Mantodea. No.1. 8vo. Cal- cutta 1889. | The Indian Museum. VOU. oMLYT: Pen 448 Anniversary Meeting. . [Nov. 30, ; November 30, 1889. ANNIVERSARY MEETING. Sir G. GABRIEL STOKES, Bart., 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 on the General Account during the past year, including petty cash balances carried from the preceding year, amounted to £7,433 15s. 9d., and that the total receipts on account of Trust Funds, including a balance of £2,112 6s. ld. carried from the preceding year, amounted to £4,609 14s. 10d.; and that the total expenditure in the ‘same period, including an overdrawn balance on the General Account of £953 1s. 6d. carried from the preceding year, and including also purchase of stock, amounted to £7,328 16s. 7d. on the General Account, and £2,468 4s. 3d. on account of Trust Funds, leaving a balance on the General Account of £94 7s. 3d. at the bankers’ and £10 11s. 11d. in the hands of the Treasurer, and on account of Trust Funds a balance at the bankers’ of £2,141 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, 1888). On the Home List. Ball, John, F.L.S. Bate, Charles Spence, F.L.S. Bateman, John Frederic La Trobe, M.1.C.E. Berkeley, Rev. Miles Joseph, F.L.S. Bristow, Henry William, F.G.S. Brooke, Sir William O’Shaugh- nessey Brooke. De la Rue, Warren, D.C.L. Halhwell-Philliipps, James Or- chard, F.S.A. Joule, James Prescott, D.C.L. McDonnell, Robert, M.D. Newall, Robert Stirling, F.R.A.S. Parkinson, Rev. Stephen, D.D. Percy, John, M.D. Rees, George Owen, M.D. Robinson, Sir Robert Spencer, Admiral, K.C.B. Royston-Pigott, George West, M.D. Tupper, Martin Farquhar, D.C.L. Williams, Charles James Blasius, M.D. On the Foreign List. Chevreul, Michel Eugéne. Donders, Franz Cornelius. 1889. ] President's Address. | 449 Fellows elected since the last Anniversary. Aitken, John. Hughes, Prof. Thomas McKenny, Ballard, Edward, M.D. M.A. Basset, Alfred Barnard, M.A. Poulton, Edward B., M.A. Brown, Horace T., F.C.S. Sollas, Professor William John- Clark, Latimer, M.I.C.E. son, D.Sc. Cunningham, Professor David | Todd, Charles, M.A. Douglas, M.B. ' Tomlinson, Herbert, B.A. Fletcher, Lazarus, M.A. Worms, Right Hon. Baron Henry Hemsley, William Botting, A.L.S. de. Hudson, Charles Thomas, LL.D. | Yeo, Professor Gerald F., M.D. The President then addressed the Society as follows :— In an annual assembling of any body of men as large as that of our Fellows, it must in the course of nature be expected that of those who were or might have been present on one such occasion some will have been removed by death before the next comes round. But the death- roll of the year, which according to our custom is read by the Senior Secretary at our annual meeting, is on this occasion unusually heavy, and the list recalls to us several who have taken an active part in the ordinary work of the Society, and some whose names will be. prominently remembered by posterity. Warren de la Rue, who has repeatedly served on the Council and Committees of the Society, was one of the early pioneers in the appli- cation of photography to the delineation and measurement of celestial objects, an application which has now received such great extension. He was one of the party who went to Spain, in 1860, to observe a total solar eclipse, and he took up the department of observation by photography. His results formed the subject of a Bakerian lecture, and are published in the ‘ Philosophical Transactions’ for 1862. They threw much light on the subject of the solar prominences, then, we may say, in its infancy. He devoted much attention to the subject of Sun-spots, and constructed an elaborate machine for their measurement on photographic negatives under the microscope. Several of our Fellows have had the opportunity of seeing the beauti- ful experiments on electric discharges in rarefied gases which he carried out by means of his magnificent battery of 15,000 chloride of silver cells, the use of which, with his usual urbanity, he accorded to men of science who might be desirous of investigating some point requiring the aid of so costly an appliance. Charles James Blasius Williams, who died last March, at a very advanced age, was, with one exception, the senior of our Fellows, having been elected in 1835. For many years one of the most prominent physicians in London, after retirement from medical Zi 2 450 Anniversary Meeting. - [Nov. 30, practice, in the evening of his days, he took up the examination of solar spots, and their possible relation to meteorology. ) Stephen Parkinson was well known to Cambridge men as a mathe- matician, and was the author of several mathematical works in common use in the University. John Percy was for more than forty years a Fellow of the Sue and has served on the Council. Many years ago I was myself asso- ciated with him at the Government School of Mines, where we both were lecturers together. He was a man of accurate knowledge but of a retiring character, and is perhaps best known to the world through his excellent work on metallurgy, the value of which is evidenced by the fact of its having been translated both into French and German. Owen Rees, also for more than forty years a Fellow of the Society, did good service in the application of chemistry to the elucidation of disease. Miles Joseph Berkeley, who died at the advanced age of eighty-six, was distinguished as a cryptogamic botanist; indeed in this branch of botanical science he was long looked up to as the leading authority. Our late Fellow John Ball was fora long time intimately associated with the work of the Society. Besides serving on the Council, he has very frequently assisted us on various Committees. It will be recollected that he was associated with Sir Joseph Hooker in botanical exploration, and the two, at no little personal risk, ascended the Atlas range on the northern side, being the first Huropeans who ° had penetrated so far. Fond of travel, and of mountain climbing, he was led to take up the subject of botany; and in relation to this science, as well as to meteorology and geology, he turned his travels to good account. George West Royston-Pigott took up the subject of improvements in the microscope, specially as regards the correction of the residue of spherical aberration, and a paper of his on the subject is printed in the ‘ Philosophical Transactions.’ John Frederic La Trobe-Bateman, who died in June, will long be remembered for his important engineering works, especially in relation to the supply of water to large towns. William Henry Bristow was associated with De la Beche, Edward Forbes, and other geologists in the early history of the Geological Survey, and remained in that department of the Civil Service of the country, in which he had been promoted to the post of Senior Director, almost up to the end of his hfe. He particularly distin- guished himself by the careful and detailed manner in which he carried out the mapping of the Cretaceous and Jurassic rocks of the South of England. His maps and descriptions of that region have become classical in English geology. Outside of his official work he P5000 President's Address. 45] published a few papers giving the results of his researches, and was also the author of a useful glossary of mineralogy, as well as of translations of popular geological works. On the 2lst of April, our late Fellow Robert Stirling Newall passed away at the age of eighty-seven. Mr. Newall, as a successful manufacturer, is well known through the improvements which he effected in the construction of iron rope, which rendered him, we may say, one of the chief founders of an important branch of national ‘industry, and through his success in the construction of those sub- marine cables which play so important a part in the conveyance of intelligence all over the civilized world. But he did not confine him- self to the industrial application of scientific principles; he took a leading step in the development of the refracting telescope. At the time of the Exhibition of 1862, the largest refracting telescope in operation was the 16-inch one at Pulkowa. Messrs. Chance, of Birmingham, placed in that exhibition two disks of optical glass, one of flint and one of crown, of far larger size, about 26 inches in diameter. These Mr. Newall, being possessed of ample means, purchased, with the intention of trying what could be done for astro- nomical observation by the use of a telescope far larger, of its kind, than had hitherto beenused. Theconstruction was confided to Cooke, of York, so well known for the excellence of his optical work. The instrument was erected at Mr. Newall’s residence at Gateshead, and is pronounced by competent judges to be of first-rate excellence. The atmospheric conditions of Gateshead were not however favourable for the use of so grand an instrument; and shortly before his death Mr. Newall offered it to the University of Cambridge. This generous offer was referred, as is usual in such cases, toa Committee for report. The Committee have issued a provisional report in which they testify to the excellence of the instrument, and recommend its acceptance; but the final arrangements to be proposed are still under consideration. By the death of James Prescott Joule, the Society has this year lost one of its Fellows whose name will go down to posterity in con- nexion with his memorable researches on the mechanical equivalent of heat. The circumstances of his birth would naturally have led him to devote himself to commercial pursuits, but the bent of his mind, animated in early years by the instruction he received from the illustrious Dalton, led him to devote himself mainly to the pursuit of science. Ag in the case of Faraday, his investigations were carried on without the aid of mathematics, at least of the higher mathematics. But, like Faraday, he seemed to have a sort of intuitive apprehension of physicallaws. His early scientific studies led him into the domain of electricity, and its connexion with heat ; and he showed that when a voltaic current passes through a conducting wire the heat gene- a ; | | | 452 Anniversary Meeting. [Nov. 30, rated in a given time varies as the resistance multiplied by the square | of the current. It was in connexion with magneto-electricity that his first determination was made of the mechanical equivalent of heat, which was confirmed later by its accordance with the equivalent as determined independently altogether of electricity, by measuring on the one hand the work given out by a descending weight, and on the other the heat generated by internal friction in a liquid in which that work was consumed in overcoming resistance. While much may often be done towards discovering the laws of nature by merely qualita- tive experiments, the final testing of theories which we may have been led to form involves almost always accurate quantitative determina- tions. Joule as an experimentalist was accurate in quantitative determinations, and his final number for the mechanical equivalent of heat is accepted as a fundamental constant in thermodynamics. On account of the great importance of Joule’s labours, both directly, in the advancement of science, and indirectly, through the knowledge thus acquired, in enabling improvements to be made in the practical application of science for industrial purposes, it has been suggested that it might be desirable to raise some public memorial to him, and the Council has appointed a Committee to consider the question. Only yesterday our aged Fellow Martin Tupper passed away, who was the author of works which attained a very wide circulation. I have referred, and that very briefly, to some cnly of the Fellows whom we have lost during the past year, but fuller details both of - them, of other Fellows whom we have lost, and of our recently deceased foreign members will be found in the obituary notices which appear from time to time in the Proceedings, according as they are received from the Fellows who have kindly undertaken to draw them up. Of those who last year were on our list of Foreign Members, we have since lost one who was truly a veteran in science. More than three years have elapsed since the celebration of the centenary of the birth of M. Chevreul, and two more recurrences of his birthday came round before he was called away. He will be known for his researches on the contrast -of colours. But his great work was that by which he cleared up the constitution of the fixed oils and fats, and established the theory of saponification. Few scientific men still surviving were even born when this important research was commenced—a research in the course of which he laid the foundation of the method now universally followed in the study of organic compounds, by showing that an ultimate analysis by itself alone is quite insufficient, and that it is necessary to study the substances obtained by the action of reagents on that primarily presented for investigation. Our late Foreign Member Franz Cornelius Donders stood in the first 1889.] President's Address. 453 rank among the men of science of our day. He was educated as an army surgeon; but the bent of his mind led him to scientific investi- gation, and he became one of the most eminent of physiologists as well as the most distinguished ophthalmologist of his day. He con- tributed powerfully to the advance, not oniy of ophthalmology, but wlso of general physiological science; for on whatever physiological subject he touched he left his mark, bringing as he did to bear on it an acute and original mind, thoroughly trained in physical and chemical principles, and a knowledge of the advances made by the foremost among his scientific contemporaries. There is one whose name, though he was not a Fellow, I cannot pass by in silence on the present occasion. I refer to Thomas Jodrell Phillips Jodrell, who died early in September, in his eighty-second year. About the time of the publication of the reports of the Duke of Devonshire’s Commission, the subject of the endowment of research was much talked of, and Mr. Jodrell placed the sum of £6,000 in the hands of the Society for the purpose of making an experiment to see how far the progress of science might be promoted by enabling persons to engage in research who might not otherwise be in a condition to do so. But before any scheme for the purpose was matured, the Government Grant for the promotion of scientific research was started, under the administration of Lord John Russell, then Prime Minister. This rendered it superfluous to carry out Mr. Jodrell’s original intention, but he still left the money in the hands of the Society, directing that, subject to any appropriation of the money that he might make, with the approval of the Royal Society, during his lifetime, the capital should immediately upon his death be incor- porated with the Donation Fund, and that in the meantime the, income thereof should be received by the Royal Society. Of the capital, £1,000 was several years ago assigned to a fund for the reduction of the annual payments to be made by future Fellows, and the remaining £5,000 has now of course been added to the Wollaston Donation Fund. By the Fee Reduction Fund the annual payment of ordinary Fellows elected subsequently to the time of the change was made £3 instead of £4, and the entrance fee abolished. As to the Donation Fund, a very wide discretion was, by the terms of the original foundation, left in the hands of the Council as ‘to the way in which they should employ it in the interest of science. Since the Croonian Foundation for lectures was put on its present footing, it has been made the means of securing for us the advantage of a lecture delivered before the Scciety by distinguished foreign men of science. In the present year our Foreign Member M. Pasteur was invited to deliver the lecture. Unfortunately .the state of his health would not allow him to deliver it himself, but at one time he hoped i“ - 1 >. a eta oe ee eee Se ee 454 Anniversary Meeting. that he would have been able to be present at its delivery. It was ultimately arranged that his fellow labourer at the Pasteur Institute, Dr. Roux, should deliver the Croonian Lecture in his stead; and several of the Fellows have heard his lucid account, first of the discoveries of M. Pasteur in relation to diseases brought about by microscopic organisms, and then further researches of his own in the same field. In addressing the Fellows at the anniversary last year, I] men- tioned that Commandant Desforges had kindly offered to compare that portion of Sir George Schuckburgh’s scale, with reference to which the length of the seconds pendulum had been determined by Kater and Sabine, with the French standard métre; and as the ratio of this to the English standard yard was accurately known, the length of the pendulum, as determined by these accurate observers, would thus for the first time be brought into relation with the English yard by direct comparison with accurately compared measures of length. The comparison was shortly afterwards executed, and the scale, which of course was very carefully packed for its journey to Paris and back, has long since been replaced in the apartments of the Society. This highly desirable comparison occupied but a few days in its execution ; which affords one example of the scientific advantages derivable, under an international agree- ment, from the establishment of the Bureau des Poids et Mesures. Our own country, which for some years held aloof from the Conven- tion, forming the sole exception to the general agreement among nations of importance, joined it some years ago; and we thus have the privilege of availing ourselves as occasion may arise of the appliances at the office in Paris for such comparisons of measures of length or weight. -- The services of Mr. Arthur Soper, as a special assistant, have been retained during the past session, with advantage to the library. He has completed the much-needed shelf catalogue, and the re- arrangement of the books where necessary. In the course of this work the volumes of a purely literary character have been collected together, and a selection of the most valuable have been preserved in a properly protected case. Of the remainder about 150 volumes (in addition to those reported last year) have been presented to various public libraries, and a slip catalogue of the volumes which are retained, containing about 1,700 entries, has been prepared. The manuscripts (other than the originals of ordinary papers read at the meetings) which have accrued to the Society since the publica- tion of Mr. Halliwell’s Catalogue have been collected from various parts of the building into the Archives Room, with the object of pre- paring a complete catalogue of the manuscripts at present in the possession of the Society. [Nov. 30, 7 . : ; : ; | 1889. ] | President's Address. 455 Since the last anniversary twenty-four memoirs have been published in the ‘ Philosophical Transactions,’ containing a total of 753 pages and 33 plates. Of the ‘Proceedings’ twelve numbers have been issued, containing 1062 pages and 6 plates. Dr. R. von Lendenfeld’s ‘Monograph of the Horny Sponges,’ mentioned in my last anniversary address, has also been issued during the year in a quarto volume of 940 pages of text and 51 plates. The Fellows are aware that for a great many years the Royal Society has devoted a part of its funds to the collection, preparation for the press, and correction of the proofs of a Catalogue of Scientific Papers. We have endeavoured to make the work as complete as possible, and to include scientific serials in all languages. The first part, covering the period 1800 to 1863, is printed in six thick quarto volumes, of which the last appeared in 1872. The decade 1864-1873 occupies two more volumes, of which the second was published in 1879. This work, in the preparation of which the Royal Society has spent a large sum, is for the benefit of the whole civilized world, and the sale of it could not be expected nearly to cover the cost of printing, paper, and binding. On a representation to this effect being made to Government, when the first part was ready for the press, the Lords of the Treasury consented that it should be printed at the public expense, the proceeds of the sale of the work, after reserving a certain number of copies for presentation, being repaid to the Treasury. In consideration of the large outlay involved in the preparation, those Fellows of the Society who wished to purchase the work could do so at about two-thirds of the cost to the general public. A similar application to the Treasury with reference to the decade 1864-1873 met with a similar response, and we proceeded, as I mentioned at the anniversary last year, with the preparation of the manuscript for the next decade, 1874-1883, which was then nearly ready. On making application towards the end of last year to the Treasury for the printing of this decade, our request was not acceded to. While declining, however, to continue any further the printing of this great work, the sum of £1,000 was put in the Estimates, and has since been voted by Parliament, to assist us in the publication, and the copies of the work still remaining unsold have been handed over to us. This has enabled us to conclude negotiations with Messrs. Clay and the Syndics of the Cambridge University Press for the printing of the decade last mentioned, and at the same time to make some provision towards the future continuation of the work, without, as it may be hoped, encroaching to a greater extent than hitherto on our Own resources. The utility of the work would obviously be much increased if it could be furnished with some sort of key enabling persons to find what had been written on particular subjects. I am not without 456 Anniversary Meeting. . [Nov. 30, hopes that this very desirable object may yet be accomplished, notwithstanding the magnitude of any such undertaking. Within the last year the Council of the Royal Society has accepted a duty in connexion with scientific agriculture, of which it will be interesting to the Fellows to be informed. It is well known that for the last fifty years, or thereabouts, Sir John Lawes has carried out on his estate at Rothamsted an elaborate and most persevering serles of experiments on the conditions which influence the growth and yield of crops of various kinds, the effect of manures of different kinds, the result of taking the same erop, year after year, from off the same land without supplying to it any manure, &c. Long as these experiments have already been continued, there are questions, par- ticularly as regards the capabilities of the sub-soil, which require for their satisfactory answers that similar experiments should be continued on the same land for a still longer period. In respect of such questions, the investigator of the science of agriculture is in a position resembling that in which the astronomer is often placed, in having to make observations, the full interest of which it must be left to posterity to enjoy. To prevent the interruption of these experiments, which it would take a life-time to repeat on fresh ground, and at the same time to provide for the carrying out of researches generally bearing on the science of agriculture, Sir John Lawes has created a trust, securing to the trustees a capital sum of £100,000, and leasing to them for ninety-nine years, at a peppercorn rent, certain lands in his demesne on which the experiments have hitherto been carried on, together with his laboratory. The trust is intended to be for original research, not for the instruction of students. The general direction of the experiments and researches to be carried on is vested in a committee of management consisting of nine persons, of whom four are to be appointed by the President and Council of the Royal Society. The trustees named in the deed were Sir John Lubbock, Dr. Wells, and our treasurer, Dr. Evans. One of these is now no more. Lord Walsingham has been appointed a trustee in place of the late Dr. Wells. : The Copley Medal for the year has been awarded to Dr. Salmon for his various papers on subjects of pure mathematics, and for the valuable mathematical treatises of which he is the author. Dr. Salmon’s published papers are all valuable. Among others may be mentioned his researches on the classification of curves of double curvature, and on the condition for equal roots of an equation; the very important theorem of the constant anharmonic ratio of the four tangents of a cubic curve; his researches on the theory of reciprocal surfaces ; his paper on quaternary cubics. But any notice of his con- tributions to the advancement of pure mathematics would be incom- 1889. ] President's Address. AD57 plete which did not specially mention his invaluable text-books on conic sections, higher plane curves, solid geometry, and the modern aleebra—works which not only give a comprehensive view of the subjects to which they relate, but contain a great deal of original matter. Of the Royal Medals, it is the usual though not invariable practice to award one for mathematics or physics, including chemistry, and one for some one or more of the biological sciences. No distinction is, however, made between the two medals in point of order of precedence, and I will, aig take the names of the medallists in alphabetical order. The Council have awarded one of the Royal Medals this year to Dr. Walter Holbrook Gaskell for his researches in cardiac physiology, and his important discoveries in the anatomy and physiology of the sympathetic nervous system. In his memoir, ‘‘On the Rhythm of the Heart of the Frog” (Croonian Lecture, ‘ Phil. Trans.,’ 1882), and in a subsequent memoir, “On the Innervation of the Heart of the Tortoise” (‘Journ. of Physiol.,’ vol. 4), Dr. Gaskell very largely advanced our knowledge of the physiology of the heart-beat, more especially as relates to the sequence of the beats of the several parts, the nature of the inhibitory action - of the vagus nerve, and the relations of tonicity and conducting power to rhythmical contraction. These memoirs, however, lacked completeness on account of their not taking into full consideration the action of the cardiac angmentor or accelerator fibres, the existence of which had been previously indicated in the case of mammals, and suspected in the case of the frog and allied animals. By a striking experiment (‘ Journ. of Physiol.,’ vol. 5) Dr. Gaskell subsequently gave the first clear demonstration of the presence in tke frog of cardiac augmentor fibres ; also he gave a clear account of the nature of the action of these fibres, and the relations of that action to the action of the vagus fibres. Revising his previous work by the help of the light thus gained, Dr. Gaskell was enabled to give the first really consistent and satisfactory account of the nature of the heart-beat, of the modifications of beat due to extrinsic nerves, and of the parts played by muscular and nervous elements respectively. Important as was this work on the heart, Dr. Gaskell’s subsequent work “On the Structure, Functions, and Distribution of the Nerves which govern the Vascular and Visceral Systems” (‘Journ. of Physiol.,’ vol. 7) has a far higher importance and significance. In spite of the knowledge which during the past thirty or forty years has been gained concerning vaso-motor nerves and the nerves governing the movements of the viscera, physiologists had up to the time of the appearance of Dr. Gaskell’s memoir failed to obtain a clear conception =e SS a >a SS a SSS ee ge ee $$ FES 458 Anniversary Meeting. [Nov. 30, of the nature and relations of the so-called sympathetic nervous system. By his researches, in which the several methods of gross anatomical investigation, minute histological examination, and ex- perimental inquiry were, in a striking manner, made to assist each other, Dr. Gaskell, by tracing out the course and determining the nature of vaso-constrictor and vaso-dilator fibres, and comparing them with the cardiac augmentor and inhibitory fibres, and with the fibres governing the visceral muscles, has already reduced to order what previously was to a large extent confusion, and has opened up what promises to be the way to a complete understanding of the whole subject. The results arrived at, besides their great physiological importance, on the one hand promise to be of great assistance in practical medicine, and on the other are eminently suggestive from a purely morphological point of view. The other Royal Medal has been awarded to Professor Thomas Hdward Thorpe for his researches on fluorine compounds, and his determination of the atomic weights of titanium and gold. Professor Thomas Hidward Thorpe’s experimental work has secured for him a place in the first rank of living experimentalists. His researches, which are not confined to one department of chemi- cal science, but extend over many branches, are all distinguished, both by accuracy and originality of treatment. As examples of the high character of his investigations those of the determinations of the atomic weights of titanium and gold may be specially cited as permanently settling the value of two most important chemical constants; whilst his researches on the fluorine compounds, in- cluding the discovery of thiophosphoryl fluoride, a body capable of existing undecomposed in the state of gas, and his latest work on the Vapour-density of Hydrofluoric Acid, do not fall short of the highest examples of classical chemical investigation. The Davy Medal has been awarded to Dr. W. H. Perkin for his researches on magnetic rotation in relation to chemical constitution. Dr. Perkin is well known as the originator of what is now a great industry, that of the coal-tar colours, by his preparation and applica- tion to tinctorial purposes of a colouring matter which had pre- viously merely been noticed as affording a chemical test for the presence of aniline. This, however, is now a long time ago, and it is: for more recent work, the interest of which is purely scientific, that the medal has been awarded to him. Dr. Perkin first showed, in 1884, that a definite relationship exists between the chemical constitution of substances and their power of rotating the plane of polarisation of light when under magnetic influence; and he pointed out how the “molecular coefficient of magnetic rotation” or ‘‘ molecular rotatory power’ might be dedaced. 1889.) °° President's Address. 459 ‘In 1884 he presented to the Chemical Society a lengthy paper describing his method and the results obtained for a very large number of paraffinoid hydrocarbons and haloid and oxygenated derivatives thereof ; from these he deduced ‘ constants,” which he has since shown to be applicable in calculating the magnetic rotatory power of paraffinoid compounds generally. From time to time he has published further instalments of his work, and only quite recently has described the results obtained on examining nitrogen compounds, which exhibit many most interesting peculiarities. | The results are of special value on account of the exceptional care devoted to the preparation of pure substances, and the guarantee which Dr. Perkin’s reputation affords, that everything possible has been done to secure accuracy ; and also because the substances chosen are for the most part typical substances, or belong to series in which a simple relationship exists. The Statutes relating to the election of Council and Officers were then read, and Sir W. Aitken and Professor H. G. Seeley 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.—Sir George Gabriel Stokes, Bart., M.A., D.C.L., LL.D. Treasurer.—John Evans, D.C.L., LL.D. ee adpa ae Michael Foster, M.A., M.D. > \ The lord Rayleigh, M.A. D.C.L, Foreign Secretary.Archibald Geikie, LL.D. Other Members of the Council. Professor Henry Edward Armstrong, Ph.D.; Professor William Kdward Ayrton; Charles Baron Clarke, M.A.; Professor W. Boyd Dawkins, M.A.; Edward Hmanuel Klein, M.D.; Professor E. Ray Lankester, M.A.; Hugo Miller, Ph.D.; Professor Alfred Newton, M.A.; Captain Andrew Noble, C.B.; Rev. Stephen Joseph Perry, _ D.Se.; Sir Henry EH. Roscoe, D.C.L.; Edward John Routh, D.Sc. ; William Scovell Savory; Professor Joseph John Thomson, M.A.; Professor Alexander William Williamson, LL.D.; Sir Charles William Wilson, Col. R.E. The thanks of the Society were given to the Scrutators. Financial Statement. 460 - - 6 St serlg 6 Sl Ser'Le IL jie OL ip eT } Cece eescceseeece evcceescecoeene sey 490g ‘o791(T “é ; 4 sie BF Eno) ensoruqty ‘puesy uo souvjeq ‘ e 2 6 Racers iesinisiate's() ec visleiaeieleiescisisiersted is s1oyurg qv oourleg 6c 0 OL BS see Des sncsetecceecrasvcnevevecceseene) es eeereencene woryRuog 1O}SULtALL) 66 a a 1) BAR save eovicnglceRipgnets call ag tees dt onSo[eqyep JO guNCDDV uo souRInssy ppoyesveyT Auvdmog seiryy “ G €L egg Cece rercceccecsssecsvees ie: cosseccccoes Ceneaiaies ( p), "3G C8SF aingqipued <0 snorasid Hes ee (ausy) ydeisouoy, proyuopuery “ 8 0 Ons sicasesbevusvive eecccee Covcecrncccenss ewocheve eacccece aes ah 6< Ceerscccrccccccacs: covences s0e- ve 1 ‘ en nO S| 80 or os er hoy mete ne I Sle SRO CON Wet eae ee a eee eee @ eee coecsove Teult ‘¢ 0 € 8&9 ea te ede Seed ‘Q004SOF : L It 0% “90uepeg Olan) ueutu.1eA09—norypedx a eae as : e ee Sires ge eis 3 a ee 0 0 OZL a8 Boece sot eavecccceser cocceecs fe ceeecceece r ve eeeernee suorqtsodum0g (74 Corecccsces eer ccccccerseersenveccce st (5 y 6 18 a ee) dT ae eae Ny apes ST cay sen : B61 G9 {0 S199 Sern epummeuy eau | OLR gp nn “-ayhtogt yo Sno oat pd ee et en * ena Buyavot) aiodoay voqyeryy JO ops * L BL Sh nes Glacdownel dan ant se Pes Oe os. ee eee ee ““OnsOTRYVO JO speg * [ ppaccdobopanonscEosocopetHos wee com 68 ee 20 “ DE ORE ene sO yunoaD GOS He See be tee tend, mero ume emp |g TL gag “en "ssuapanood pi SHON EEA, 0 fe (ORO, Peon AydeaSoyqwy Bae BeLanean, & Oa i Parner Seconreniieeaate Srenegeaee Seve OW, Wer jeanen[ Uy Se ait ee ee a ea a Eo Ee SoS | comer gp Supt “| PBL OLB “on apn aK Jo ap) epuopttt P ZL SIZ ce ee ania G aI 609 Peccreryenvccee CORP eer cceeseeeeeescereseeers. sees eerccecccere squey punowy (73 Rr - I 2 ; a eq 6 Core ceeerersccrsensenns eeee: ee eet |g ‘eho {0-784 SS oe euret one Sy 9 Sth “626 OF TLE SON ‘sSuIpecoodg once “ ‘pS §F isquey “ a 9 OLT is ooo eeeeesesscseossceresoes 7 se eeesceee seed 0) 0 062 Cores esceccesesvecsceece Cor oees cess creceseseuc e SUOTINGIAQUOD jenuuy Ps g oRoee eae eine aan crag“ (Lee ee ee 5 Eg ee ree ee ae ear atancua (er wood [0 0 Oa “eR 4 OFT sg gee a re) PL 99T Cor ccccceeccvereceesoesesesseascocse s1odeg OYIGUIIO jo ON.GOTVIVO (75 O 0) 450) I { 0) 0) Ze9 Secrcee e “SUOI natrjuo (73 Te ee ee 0 ee ee - a ve SSST ‘TIGUIOAONT YIZT ‘UMVApsoao oourlrg ‘sroyuvg Aq IL G 6 L LT PL Junoooy onsopeqep ‘puvy ut courleg og, i ee UG "68ST ‘WIST “equmaaon 07 ‘SST ‘UIST taquaaony wouf ainzrpuadag pun szdiavay fo zuamaznjig “6881 "Ja0YS aounjwg 461 OL FL 609VF OL FL 609'°FF y SI OLZ ~~ JuNOdOV puny Foljoy OBIQUOLWG 4 OL TKI? i HL tehBL klekeoy OU aG AROMAIOUIN Oa T SAGL : js SI TLUT Oo ooccecooccsscsovovcocssoce qunov0Yy [Badu —' sloyuvgd ye souvreq “ (Oo ra Z8Z eececcccvccsccescosccecesorcones quoUlysoAUyT pue Fe sosuodxq ‘pung Jelowmeyy utmaeg “ (O 8L18 ““spuepraiq ‘puny [enomeyy uTMaed 2 G ZIS ever sececorccoceves eeeeccersvece (688T) qunoo0w | 9 ZL PIP “SpUapIAl(] “puny uoTgonpey 90.7 = etousy Lyorooe pedoy 07 aAojsuvay 9 FGSfeORlt Pees a pede spuoplaiq ‘puny Tjoapor RS [pres eee ues LAT ‘puny uoronpey oom spel Ones. S77) stern. ““ spuoplarq ‘pung so; puvzy Ss | 9 G Cr See soccevcsccecs coves weer eerscece cece puny uolyeu Z it S6r Case rersenre mm) Y ‘spuaplalqd, “‘qsn.d J, JOISSt 4) Ss -O([ 09 pue yunosoy Terauang Lyo100g CoE et ean / aera eae GP spuspliq ‘pung [epeyy sang W jedoy 0} aozsuray, Spung qetpor “ 8 6 OG “""" guey—puUng sInqoarT urluoc0IyD Es P Zz L8T Cocrcnscscvsoss -SqUsUS BF ‘puny AoyTpur Fy 6c 6 8 L6n‘% 4 0 el eg “Om ‘spuepralqy ‘pun i ULVY.OULAGUT AA 3 | 6 ST cee Oe cece scence seesoess pee a pur 909} TUL | 0) 8 Ones a eee eons spuoplarq Seealiod yoy 8 ee MOD MAY OF sqaUEE YSN, OISsED : 8 OL9G wav epihe asa base ‘ow ‘spueptAtq S 9 F GE" STepeT! PlOH “puny yepoy Aavcy | ‘puny [epeyy Aoqdop pue uvmoyeg 2S 8 Sl Pp —“ squowdeg ‘pung ommgooy uetuoorg “ Ce COE eee spuepiig ‘pung pazoywny Sy | Bilt Le Occ c ces eeeresesaver sees qenidsoH Surppunoy | GOON O Ge ak a eras oe puny Tetpor WOLF LF 04 quowded ‘pungq weysuryuray “ “eee aa EEC GE pun 7 uoRru0g ry 8 &Z Cone e cee caecenesecccoereterncctarees peccoece £xexa.1099 Se) ZI 9FO Deeeecce sercoes oe cecessecee eee ““SuOTZVUOG pus UsTONO 04 tote pealeor, yooy “ ‘spuepmiq ‘punq jeljoy oyuelog O BL SQ re qgLD pur ‘7epow | OL 0 Ze ~* gunossy pung Joroy opquoIOg | ‘pung yepeyq Aeqdop pue urmoyeg “ T 9 ZITS 42 1 96% “* JuNoooV pung uoronpey oa7 6 P 9ST ocescere qIO pue 1®p°W puny paxoyuinyy 66 T PL eOr‘T ee cc ceresececee seccceece cece qunoov0y [ereue4 0 SI CES eoccecce sorcerer eye scece SJUBLY) ‘puny uoleu0d 6¢ est SS8T LO 0 886 “""""" sqUBID “puny Jorfey ogruerog Ag ‘IOQUIAAON YISL Yueq YB eourvjeg Comes 3 Die Sis ae PS. S: oP 8 AF ‘spun JSNLL 1889.] : P Finaneial Statement. | le) —H ‘9O68'TF ‘isonbog uvdyoAory, ot, y ; ; oooer ‘ung foNSe ee y04FG aANjJUEQeq “quopH aod F AvATIEY UAOTYTON Jrotn 9GE‘OR “WNIT, JOISSeH OT — spucg UoVoltty uripejyy OOO‘OTS ; ‘pun yepeyy fa nace eee nope \ yoojg "quop zed g poojuvieny Avmpey svapep 099'C# ‘qsonbog yoo y—' 40049 oanqueqeg “yuep sod F AVMiTeYy purl[pIy QOOF ‘sosodang [etauey—"y00}g “quan 10d Se vipuy QOO'LTF ‘puny jepeyy Ao[dop puv uruoyeq—yooqg “quep tod 3g MONT “pg sg SOPF ‘sosodan g [etousp—"eqersgy joouyg UEMTATOD OT) JO eTeS ULOIy BuISILL ‘ALODUVYO UL “PT “ST Zop‘eF puv Hey ah OL Ae sion a bug Tebog Dee Rel ee We dae ae = 0 ap Ae vais Lee NE AON Hae CNEL hors “Wo0}g poyeplfosucy “quog sod £z “pe “sg F2z'PIF 0 0 00z‘T Cec ce eee e sneer wore eecseers sees esescesseseccess cove pun jy ULVY.SULLJUT AA 0 6L CEES nee Cece ceca sees So eveve recs eeee secs eres verses esses sees® C880 pung piosmny pS F —spuny Surmoypoz oy} Jo JUNI UO “yZ's) ZAL‘OLF Suloq ‘quoy sed pF ‘uvory o8v5410T OOO'CTF ‘(68-8881 Ut “PS “so PSF poonpo.d) O00STF YG Yur_ pue soymuuy quowusaop ue 4sodojui [enuUT YAAMOJ-0uQ “puoplarg daoouvyy ysenbeg uostieseqg . “puny emnqoory uviuoorg ‘umuur red gogx qnoqe ‘suetomd{yg Jo eSIT[OD oY WOT cH Yeqmey 7V o}vjso uv Jo JOA AVTO BY4 JO YIFY-9uC ‘wnuue tod ‘sp ELF ‘xossng ‘somory svou “Guey ue g_ 90,7 ‘unuue ted eGz¢F sjuer ‘UO}SUISUS TZ, SO AA ‘PROY UOJILYEAA UT sosnoy Ez jo ‘wnuue tod OgeF quot “Qoor49 [[eYSuiseg ‘JG “ON BSNOTT Jo quay punoryH ‘unuue tod QOTF quot ‘(az “UZ “VEG) oatysupooury ‘odioyjo[qey, 9v 07B4SEL 66 66 ‘spun Isnt Burypnpour ‘hgaroog yohoy oy fo hysadoug pun sajnpsq Financial Statement. 463 1889.] ‘ava NHOFL : ‘HTHOOO SUNVE ‘CH MONA MM TOATAV “AMaAVIO UV “aTOd WVITTIM "q00L109 MOY} PUNOF pues syUNODDY oseyy poutwexe oavy ‘AJOIOOG oYy |] *JoeTT00 TOY PUNOF pu sqUNOdDDW oseyy poutUTexe oAey ‘Tour op 93q} jo qaud 04} UO syUNODY s,lodnsvory, oy} JO sdoyIpNy oy} ‘OM jo yxed 04} UO syUNODDY s,toInsvery, ey} Jo s10z1IpNy om} ‘OAA ‘dounsva4T, “SNVAG NHOL ‘qunOnY onsoTeyeVO— "GEST “YIL 1940900 onp Sutumo00q “coufO eoULANSSY seTyW oy ur LoT[Og 000'T FF ‘pung Soppuepy]—yooqg peoyuereny quop sod F Aemprey oarysy10X puv oaryseouey g¢ LPF ‘puny Uo1yeuog—"y00jg pooyuereny “que sod F Jenjod1og Avmpey usoyyAON yeory OEO‘ey ‘sosodaung [Btouepy—"yooyg eouodozorg “yuop dod 7 Avmpiey ut04seA\ YJNO pu uopuoT GEE‘ER ‘puny Jolpoy OYTFUeIoOg—'yo0qg sanqueqeq ‘quan aod g Avampiey usoqysey Ynog OPE'Py ‘puny [eMowepy UIMIeg—yooyg oanquoqeq ‘yuo sod F Lemprey uroqseq YINOY EOZ'ZF ‘sosodang [v1ouep— 407g oouodozorg “juop aed F poyeprosuoy Avmpey usozse AA YON! puw uopuory CQO‘es "sosoding [vlovep—yoojg ooucdezorg ‘quoy aed F Aemprey udoyseq YAO 000‘C# ° d ¢ spungy JoreH ONTIUOIDS ooGaR [ILO PeeimEreny poyprosuog queg wed “ “Ostet ‘puny woronpey 90q—"yoo;g ornquogog jenjodieg “yop aod F Avmprey u10}se A TILON puv uopuory goo‘ Ma? ‘puny woyonpey oaf—"yo0g “yuop dod $¢ uvqrpodoayoyy 006 ‘FF I VOL. XLVI. we NN te NE ie TR re ian A a so EM on Trust Funds. 4 j 5 —_—_— a Il 8 P6LF : IL 8 ¥6LF It yt TI Il OL oge Cee eee Or eee HOO FOOD OEE POOL OEEOED HOSES DEO DHL 00s BOb00 FOOSE EH ESOEE DEED eoURlEq 19 Zz ZT 0&z hcl ceo vse seers eres ere eeulesssseee Oe: dereoers -sassces ener ossesesy spuoprlAl(y cs 0 SI PZ Core recescceeceesoeeseresorscose ee Chee eee csce cee reese reee eee erer eesesees SURLY) Ag z c ZES sepa tepeseespecmaaresehareassaren es *Se Fei spe icrak aiececie, Ae eouRleg OL Ds Ff ps FF wa "yo04g oanquoqog “quoy aed F Aemprexy uroy AON Jory QGS'TF “ysonbeg uedjoaory, OUT, | "Y00}G pooquvasny yuen aod F tenjgodsog Avmpey ULOTILON FVOAH OSO' SF “pung Uuorunuog b €l 866% | » eT seer 000 coe 0 eos oc De Leo DGG HOC GOOGO BOLE OOAUD HOG DADI DOES stlorgd1osque jenuny 6¢ OFS peccccccccccsces Meccnece sees Seeeeresseseneseserenorssrsssnecrereenes SpuoprAl(y ce 9 IL OV9 : ANTE (ONS "948A UI-LOAO yeqyideg—ssory oe OL oO. ess = Sl Onk L © OSH “"" OUMOOUT “puvy Ul coURleg 3 € GL 98 Geeceoecdeesoore peqsoa % -ul-10A0 = - [wd BQ — ssoT > oouryeg Oy, 0 0 822 PrreeT TT oor sqUBLK kg T el 88e eresee apensterssaedenssstre > OULOOU |: Ds: pike Bay Ded . a "y0049 oanquegeq “que9 zed ¢ Avmpey Us04svqT WING OFEFF : *y00}g aMnguoqe *jueD sd F AVMTIVY ULoYAON BL 000°SF ‘yoo}G pooquereny pozeprfosuoy ‘quep sod H “A AMA'N ® “I 000'9F pung foyay orjuarag ‘688L ‘Spun ISNA 465 Trust Funds. 1889.] 0 8 eZ COLOH DE OO OTD EDOOHPeEoOe er eCEHpDOD 4£77842,1009 Us1d.40 074 quow keg Ag 0 8 eZ OPP eererPorcerpeer POROPO e POH DORBDODE CODD DPOPOHEL HOE perpeproenED spuapralq oy, "QO0IG omyuoqe(y -yuep sod F Aempey purlpryy O09F ‘gsanbag yoay ayy, OT LATE 2. OL ZL0s 9 P 6IL 400000000000 0000000000000 00000000000 LEC DOE DODO LOSS OHH ODDS SOSEHEDEDOLE souvleq 6¢ 00 F einqjooTyT uvltoyeq—odioyy, pue 1oyony sxossojorg “ O PL OP “eereeteeererns omni s Lojdog ‘pf a1g—puepraiq “ 0 0 0g “aFTD 8 Aoqdop ‘f aIg—do[xn *H L Jossejorg 8 9T 6 Uren Yooyg -queg Jed 4g Men ‘spueprarq “ 0) SL OOOH HOHH HOOT HOECAODOH CHOKE HTHGEOHHOHOHLHOOOOE @cocerevccvosereedcooe [Te pet Ppl°ey sg OL G IZL 9000066 OOOSOTSOOHOOOOAHEOOOHOE OOS CEOOHODOSOOG DSTO OHHH ODODE SESERTO G08 QouUs/ Ba OL Teta i i | "YO09g “quay aod $% MON “PQ ‘56 GOFF "JOOS POFBprpOSuoH -quop sod $z “pH “sel 999TH WHO 8. 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F ees eae *Y004g poyeplfosuoy yuoH rod FZ “sEL GEESE “pung pLofiunay N = N : 3 a 3 q as 2 Trust Funds. 466 | 4 GOLF , 4 % 601F T 0 yy oe eco eb cero esses ress es HOSES O TOES OE SOHC SSESUEDOODFOSODESSDOES BOO0D 08 soueled te 9 e Ze 00060000000 00008 F000 OEC OOO OSLO OOO: 200800008050 SEOs OEE oes serereeued SpUOprIAl(] “cc 9 P Ze Dover eee cnvee veneer eeesecesecorevererensroreraserereveversreceee s[Bpo ploy kg Te ak LL © 0.0000000000000000009000000000000000 00000900 00080n0eservscsevcvconrsoens eounleg ol, 7 °s , F ‘p °$ F *y00}g *gueD zed g pooquvauny Kempiey svrpsyy 099 “pung jopepy haog é ne | 8 6 OSs cee OSF 8 eI pp erneneennenseenencesenseeneerserenenrgtiny LOSSoJOrg—eanjoory . 0 OL G 860000000000 000000 se 0000 0d 0000000000 S881 ‘IOQULOAO NT 48 eouRleg kg 8 6 0g 0000 00000000500000000000 000005000050 0008 80008000 00000 HO OOD RELL O NEE’ B00G0E0e quoyy OL “p °*s F “p “3 ¥ i camuue sod Zogx qnoqe ‘suvrorskt_g JO eSo[[oH oyy mody “TLE YJequILTT ye 07BAST] WE Jo JU avoTo o4y Jo YIFy-0uQ “‘pung alnjoaT Unwoo1g § 8 085 | Booths SS eo cer dedoccdeocecsosdoddscedeces odecrdedededobooeveccDen0snec00000000100 souvleq ce 0 &t gg £0.0000000000000000000000000000000000000 10000000000080008 000000000000 spuoplAl(yT (3 Ie sosnnssesseanereeranessereteeenr gat SOT Surppunoyy 0} quoudkeg kg € SL OF 0.0000000000080000000000000000000000000 0eceoeoesrovedecednerdusesneo neces eounleg OL, aa ps F ‘40099 poyepljosuog “que xed 2% OOS TF “pung wWoYyburiqury Trust Funds. 467 1889.] 9 & SIF 9 G SPIF QZ TL TL reetnerrtessrrereerseserenryees yaqumeqdeg pxg sous spuap ‘IATL JO uorjzodorg—pung uoyeuog “ ‘6 Th Siete t ee gunoony, [Bt0te-—) Aqora0g jesory 0} TAJSUBLy, kg 9 8 GFT “p °g or m @ f "FO0IG poyeprfosuay yuUeD tod £% "POL “SPL S8T'oF PUT [ane aay OPPO PALOCCoHOoLO So eOoOOANHOOD HOP TP Or=H9DOGIEss PONODHOD/ IIOP PIYoOe® BpUPpPrAl ay, ee ee rer PG LIF : b & LSTF P & LQ wrerrseeeveereerreseee arnogay ens0[BIBVy 0} coysuBay, “ ve 0) 0) OOL COPD MMOH OD PL CO>D HD LORD ED OODODOOBO PHO E EDO GeHODESS ODD SNES IN048®B I qn suy kq 7 be L81 PPYY peop roe opepePatoadep oop ooaPHoarpPOLO0D OI VANYLOOD, BNREOLE SPUOPIAly OT, a mS "Y009G poopuRARNH “quag Jod 7 Aumypeyy oxtrsy.10 A pus oirysnouy S6L'VF ‘pung hopungy g 4 o9sF g 4 0say IL 8 PL $8 FOP SOOO OO OGOO OOOO HOD IDOI DOOD OD ODODE HOODEO OOD SHEED SOS DEN OHO EDD L ODODE OULU 66 6 8 SP yoog poyeprposuoy “quan qed £2 ose jo oseyoan J 66 Z LZ S6P COCO OOOOH OED HEE OOO OOOO OOOO EE EO REDE TODO SE DOES DOS STOODEO ESTO 40 000008 SpueprArqy €e @) OL LSP Settee eer yin Le OR UULLO G) MOY 04 syuou keg Ag 9 6) zg POV Ceo a ror He HORTON OOD HO OH OHEH ODL TOOT DONO DOFOD HED HHOOSHHA SOTO OOTONOND eourleg OL Bp: Bee "Y00FG poyeprposuog -yuoy aod Fz OOPF "SPUO UOjestaty wvipeyy, OOO'OLF "PSN, 20880) YT, 4 Trust Funds. tie MIM RC TERNAL EAT OE Ri Ck a ee 468 (renter oe aeeri T! —— : ae mo CO SRE s 8 € ITLF 8 S8T 86E 0 & 22 0 O 0626 9 6 COSF LI 082 ST 692 GT 6G ‘sg | ase agg 9 6 S9SF OL FL OTF “peysoaur-aoao jeyduy esory v OL OS ee ae ee eseree ouloouT ‘sounlug 66 Pero c er eraser eee rere eaer5 SP 9GOUO DODO RODEO EUE DELO EO SOEETESOEE~SOO00SR IONS YooqN 0 ST 18 0000 000000000005 6000060600 000600 0000060004 1000000000 18 00000000000000 spuoptatcy es emyuogoc, 3u9Q 10d H ‘was OOS Fo esmyoang “ dovesseededdcvercvessocesssdnsssvooovcer ad SULABIOUTT pus Surquig kg 9 TI 187 vote 8 T 6PZF. ‘Tepyidep ooUuBleEg OL Dies) aes i *y001g eanquoqeg “jue9 sod F Avmpey uTo}sUm YINOG 00S’ CF . . ‘DUNT [DiUOWayT WIMLog 8 ¢ TI4d ol Codes ed SSHSdbod OSS OCEDODAEEOOOObE HE ObOOEb OEE SOSOSbOdEGbOSSbDODEbB0020b0 sdUBleg 66 y0090 “‘quen rod ee ueqrjodosyo pq OOZE jo OsVyoIn J 66 9 Or PIP 6666 0000660666050006580008 645605 007d5005 b55bb5db yD: bodrnoorsecre sine sptioptAig &4 seedertiooea nooo [earoue+4) Ayero0g jedoy 0} TOFSUBLT, kg z VL je 962 00005000 0000000000000000 6600 200000)008I00N 00014 L000 0G ROR POLOTOTIIO. O10 oouTleg OF, : kek aS *y009G ornquoqeq jenjodiog ‘quo tod 7 ABMIEYy UTSISI AA YILONT pus UOpUOT OOO'ZF *yoo}g “quog sod Sg uvqyodoroyy, 008°FF ‘Pung UOLYjINpay aa 1889. | Appropriation of the Government Grant. A69 The following Table shows the progress and present state of the Society with respect, to the number of Fellows :— Patron ™ Com- £4 £3 oe Foreign. pounders.| yearly. | yearly. Total. Nov. 30, 1888 .. 5 49 182 160 127 523 Since Elected .. wae m4 + 2} + 1] + 18 | + 16 Since Deceased .. Ke — 2|— 8| — 10| — 1) — 21 Nov. 30,1889 .. 5 47 176 151 139 518 Account of the appropriation of the sum of £4,000 (the Govern- ment Grant) annually voted by Parliament to the Royal Society, to be employed in aiding the advancement of Science (continued from Vol. XLV, p. 69). 1888-89. & Dr. R. Stockman and D. B. Dott, for a Research into the Chemical Properties and Physiological Action of Bodies derived from some Alkaloids by Substitution or Decomposition ...... 20 J. V. Jones, for the Measurement of an Electrical Resistance ~ in Absolute Measure by the method of Lorenz .............. 50 A. P. Laurie, for a Research on the Properties of Alloys tested in Voltaic Cells, and replacing the Zine Plate therein. . 20 F. R. Japp, for an Investigation of the Reactions of Ketones, Daketones, and) Alied*¢Compounds ..)s0..24..02 0005s ees ee Zo. A. M. Worthington, for an Investigation into the Tensile Strength of Liquids at different Temperatures, and into the Relation between Stress and Strain in a Stretched Liquid.... 20 Hon. R. Abercromby, for the Investigation of British pWimmdenstormsh ss 2c seke ks wh es aves bout warevans Jee od ae 25 A. R. Ling, for the Study of the Halogen Derivatives of CONES fay aie SAS Ae oo med hee ae bo ae Poko n Cae: oats 30 G. T. Moody, for the Investigation of Isomeric Xylene Deri- MAES vaeralererdiecd Ne, watatsea a ailla, 2 S020 SAMUEL WES E Va see 25 G. J. Symons, fe completing the Collection of British Rain- fall Records for the 17th:and 18th Centuries. ....0......0006 50 Carried forwards je. cs 66 oo ace Nae. wold 47V Appropriation of the Government Grant. [Nov. 30, = i ae Brought forward \,..... eves O20 Oe C. I. Burton, for a Research on the Heat produced by Compressing Solids and Jiiqurds ., 0s. -. 985.2202 e eee 50 0 0 J. A. Ewing, for Researches on the Magnetic Qualities of Tron and other Magnetic Metals......4.5.:.....-.- 60. OF 50 T. Carnelley and A. Thompson, for an Investigation of the Relation of Solubility to Fusibility, more particularly in the case of Isomeric Organic Compounds............ 20. .Q 30 H. R. Mill, for completion of the Discussion of Observa- + tions on the Temperature of the Water in the Clyde Sea Area and the Sea-lochs of the West of Scotland ........ ao Oe S. Skinner, for continuation of Researches upon the Substances produced by the Action of Phenylhydrazine on. Urea "Derivatives: cite sicns ses eee ee eo ee eee 30 0 O J. T. Bottomley, for continuation of Research on Radia- tion Ot Elleait \\. sate, st ae oe aie ote woe pemooe colons ole oie cee 100" :Oes@ A Committee of the Royal Society. Balance of Expenses of the Solar Eclipse (1886) Expedition........ 207 1l 7 G. S. Brady and A. M. Norman, for expense of Plates to a Memoir on the European and North Atlantic Ostra- COMA cs sib sic dele ehe a iane we sre uel’ shape cuer el aels Yo nol hele one ee 50° 70.0 L. C. Wooldridge, fan further Research on a New Mode of Protection against Zymotic Disease ................ 100: Oe Liverpool Marine Biological Committee, for the con- tinued Scientific Exploration of the L.M.B.C. District, Liverpool Bay, and to aid Mr. I. C. Thompson in his Re- search on the Surface Fauna, and especially the Copepoda 50 0 O T. Johnson, for the Investigation of a Number of Obscure or Unknown Points in the Floridew............ 30) "Cae H. G. Seeley, for an Investigation of the Permian or | Trias Reptilia in Russia in Europe, and Cape Colony.... 200 0 O G. Massee, to complete a Monograph of the Fungi be- longing. to the, order Thelephoret. 22 scsi tjek see ) Se Report of the Kew Committee. g I agt Peo serodeeescsererdhdusunerees diouee "Oo" ‘souvBINSUT uety ‘Tony ‘SBD 0 Or L8P Oe aaa eek Se pa aaa dh og (sn.ty, JOISSG4)) £01008 wioy 0 8 GrLiF Seine SeC trees oc ee ale dcinssioe ceee ney Cscse esters eet cete PTGS pues SOTABpEs 4g OL 9 RD eee eee eee eee ee siete ee ee ee erent Oe S TNS 88-1881 WOd} JoULR OL ie = ‘SINAWAVd ‘eT dIMOW te Ta A84 Fieport of the Kew Committee. 485 APPENDIX I. Magnetic Observations made at the Kew Observatory, Lat. 51° 28' 6" N. Long. 0" 1" 151 W., for the year October 1888 to September 1889. 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 Magnet 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 35 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 employed 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 7, to an adopted standard temperature of 35° F. is 0-0001194(¢,—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°83 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 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 / m Sant (1- & , is —0°00205. To" In each observation of absolute Declination the instrumental read- ings have been referred to marks made upon the stone obelisk erected 1250 feet north of the Observatory as a meridian mark, the orientation of which, with respect to the Magnetometer, has been carefully determined. The observations have been made and reduced by Mr. T. W. Baker. 7 sp Da aot Nets Nai a sd hives) osetia a Th ne 1 ae , RE WS portent C8" n Pat ? 486 Report of the Kew Committee. Table I. Observations of Inclination or Dip. Mean Mean Month, Inclination. Month. Inclination. 1888. 1888. October 30......| 67 84°9 April 26......{. 67. 85°1 BE, cece al ABT Sack 27... can) ge ae Mean...... 67 34°6 Mean...... 67 34°0 November 27...... 67 34:0 May SES SCine 67 34°7 DBs sieitais 67 34°3 SOLACE ae 67) 6324 SSS SS 31 ae 67 34:1 Mean...... 67 34:2 ————_— ——_—__—_—_ San Mean.... 67 33°6 December 24...... 67 34:2 7 fee Ae 67 34:0 June DA eae 67 34:1 SS 25 67 33°8 Mean.. 67 34:1 ——— ——_——. Mean.... 67 “sar9 1889. Jul 29. 67 33°6 January 28....... 67 34°2 y vere : hae eee 67 34-4. SON. Herete 67 33°5 Nan te hes 67 34:3 Mean...... oi 33°6 August 26. 67 34:2 February 25...... 67 34:2 8 ie ; Ble voids | ain Tig Bbct | ar ee Mean...... 67 34:4 emer. of 34 Gola Mis? “See 67 34-0 October 3..... | 67 34 ide Ss cleloler 67 34°6 i Mean...... 67 34°3 Report of the Kew Committee. 487 Table ITI. Observations of the Absolute Measure of Horizo ntal Force. Log = Log mX Month. xX Value of m.* mean. mean 1888. November Ist ......... 9°11991 0°30822 0°51768 November 29th... s«...«. 9 °11952 0 30828 0°51749 December 28th.......... 9°11977 0 -°30826 0 °51763 1889. January SOth......... 0s 9 -11946 0 °30842 0°51754 February 28th .....6.<. 9 11944. 0°30839 0°51751 March 29th .......ee00. 9°11925 0°3084-4. 0-51742 | April 29th and 30th..... 9:11919 0 °30843 0°517388 May 25th and 27th...... 9°11876 0° 30860 0°51723 | June 26thand 27th...... 9:11873 0 °30857 O-5172i jnlp ice ee 9 11846 0-30845 | 0°51696 | mesh 29 ~ se 8! e eos 9°11852 0 °30847 | 0°51701 October Ist and 2nd ..... 9 11830 030833 | 0°51679 | | Table IIJ.—Solar Diurnal Range of the Kew Declination as derived trom selected quiescent days. H Summer Winter Annual our. mean. mean. mean. 1889. : | ; | y Midnight —0°7 —0°8 i; 0-7 1 —-0°9 | —0°4 —0°6 2 =I" | —0-4 | —0°7 3 cl Fane —0°2 | —0°7 A SeGe le = O-4e. ie | nO 5 Orr. i | SH OBhe. fyo aee 6 — 7 Ae) | -0°6 —1°8: 7 =35 | -0% =21, See eee ec) aT On 0h ee 9 oe ie Oe, in 5 = eG 10 —0°7 | =) | —0°5 Tul Pg icy RSS Ve AM ate cy fee ee ArT] Noon +40 2) te etehe 13 +5°3 | +2°9 : +41 14 HART he POEs a aed 15 +3°2 Ree een 2 | +2 °2 TG ay! Unreal Gis is OS ei] 17 +0°6 | +0°1 +0°3 Pay | 0-0) Ort 0:0 if) —O°1 | —0°3 —0°2 20 | —0°3 —0°6 —0°5 Ze er OS ahr 2 0-9 —0°6 22 —0°2" | =0'9 | =0°6 23 —0°4. —0°9 —0°7 When the sign is + the magnet points to the west of its mean position. * m = magnetic moment of vibrating magnet. 2 iG 3 488. S : S 4 KS S eS > : =) PSLv- 0 &oZP-.0 TSZV-0 GGLP-0 TSLP- 0 OSZP- O LPLV-O 6PLV- 0 SPLP. O “2010 iT [201 86EP- 0 L6E8V-0 P6EP- O POEP- O S6ED- 0 66EV- O G6EV- O G6EP- 0 T6EP- 0 S8EP- 0 O6EP- O 68EP-0 "9010 iT [BO14L9 A 10 ‘XK FIST: 0 EI8T- 0 EIST 0 ZIST- O ZI81-0 TI81- 0 ZI8T- 0 II8T-0 "9010 i] [U}MOZLLO FT 10 “X ‘aImsvoyl "SD ‘O 9494-6 | 6268:> | 9PI8-T o494-— | Zy6e-b | SPTS.1 ges. | ge6e-b | 9FI8 T eesz-> | Tr6s.F | eFTs T 6zc4.F | O868.F | SPIe-T 60¢.— | Steer | OgTs.T Lcd. | ez6e-p | 6e1e-1 4094-6 | gt6e.> | PeI8-1 pOcL. | 116s» | PZTS-T TLbL-b | 6488-— | FITS. 1 O6FL-> | gese.F | OIS-T O84-F | 6888-> | TLIS-1 aes ar “0010, LOR ron neeH ‘SHU OLOTN = “AVISUOJUT OLJOUSL I, €8Té-OL 69TE. 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Le ok aap RIOT qos pur qyiung ° TSLP1 rl) kee “ “ “ *¢- 18 [-GT c.TE 6- 18 7°" K1qU9A0H “tepuel ply “a = GZ9ZE + oqvodaar pues yYdexrsouoazyo spuooes pus oynulpy ay “MOTIISOT ae 010) lees @) -erod may, oe -V11G A ‘syIvUr fq poysodeq “OQ UIN NT “yoyem JO uoydri1osaq T2107, IOF POPIVM SHV] ‘reok oy} Sutnp soqoqye A poyeorjdurog Aq poureyqo sproosy ysoy.oryy TL 34%L— TI XIGNHddV Report of the Kew Committee. APPENDIX IV. A95 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. To whom lent. G. J. Symons, F.R.S. The Science and Art Department, South Kensington. Lieutenant A. Gordon, Professor W. Grylls Adams, F.R.S. Professor O.J. Lodge, E.R.S. Captain W. de W. Abney, F.R.S. Prof. T. E. Thorpe, F.R.S. Lord Rayleigh, F.R.S. Articles. Portable Transit Instrument............ce0. The articles specified in the list in the Annual Report for 1876, with the exception of the Photo-Heliograph, Pendulum Apparatus, Dip-Cirele, Unifilar, and Hodgkinson’s Acti- nometer, Unifilar Magnetometer by Jones, No. 102, 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. Unifilar Magnetometer, by Jones, No. 101, complete. Pair 9-inch Dip-Needles with Bar Magnets... Unifilar Magnetometer, by Jones, No. 106, complete. Barrow Dip-Circle, No. 23, with two Needles, and Magnetizing Bars. Tripod Stand. Mason’s Hygrometer, by Jones ............ Seip OMS tame Saperet oreo lane « akoneceheler orstereysfohs ths of an inch, for which a correction was also applied. The expansion or contraction being equal to 0:005 of 1 inch for 1° F. for one chain, the distance in chains, multipled by half the difference between standard and observed temperature, and the result divided by 8, gives a correction in decimals of a link to be added or subtracted, as the temperature is higher or lower than the standard temperature. To the handle at the back end of the chain was attached a small 2m 2 a SS eee 514 Prof. R. Threlfall and Mr. J. F. Adair. On the piece of steel with a knife-edge, and this was regarded as the end of the chain. This end was worked by means of a slow motion screw attached to a board, on which the chainman knelt, and so the end of the chain was kept perfectly steady. The knife-edge was brought by the screw to the mark, which was a very fine pencil dot on a piece of white paper, gummed on to a flat-headed nail driven into the ground. On the forward end of the chain was hooked a spring balance, which indicated a 16 lb. strain, applied by means of a light straining pole, 12 feet long, thus enabling the chainman to apply the strain far more steadily and easily than by any other method at present in use; and also allowing the full length of the chain to be used on a slope equal to about 1 in 5, the end of the chain sliding up and down the pole. The greatest slope in this case was, however, only about 1 in 10, and only for two chains of the entire length. The forward end of the chain was taken as the position of a small hole, through which a string, with a small plummet attached, passed. This plummet was used merely to indicate the position of the nail, and to keep in adjust- ment a contrivance which gave the position of the transit theodolite (carefully adjusted for the telescopic axis) at right angles to the direction of the chain. The end of the chain was sighted by means of the transit instrument, and the telescope being then depressed, the fine point of a hard pencil was lined on the paper before described. This method does away with any errors due to the use of the plummet (especially in windy weather) for marking the end of the chain on sloping ground. By the use of the instrument the end of the chain can be marked to 524,th of an inch. This method has also other advantages for accurate measurement. | The instrument used was a 90-inch transit theodolite, by Troughton anc Simms, of London, having the circle graduated to 20 seconds. The telescope was larger than, and of much superior quality to, those usually fitted to 5-inch instruments. The plummet was suspended from the end of the vertical axis. The instrument was used on a traversing top stand, and being in very good order, and the axis moving freely, there was no twisting pressure (torsion) on the stand, and the day being a cloudy one, and the sun completely obscured, the effect of sunlight on the eyes was avoided. The instrument was care- fully set up over each of the points A, B, C, and D on the base-line, and angles were observed to the spikes in the piles (points E and F) off line AD. The angles shown on the plan are the means of four readings at each of the stations. After the first two readings the telescope was turned over in the reversed position, so that any possible errors due to change of focus (movement of the optical axis of the instrument), want of horizontality of the telescopic axis, and imper- fect collimation, are entirely eliminated. The levels were sensitive, and of good quality. The readings of both verniers were recorded Velocity of Transmission of Disturbances through Sea-water. 515 and a mean taken, and each angle was read off a different part of the graduated circle each time, so that any error dus to eccentricity was entirely eliminated, and any errors due to imperfect graduation were reduced toa minimum. In repeating an angle on the graduated circle, not only is the second measures of the angle given on a different part of the circle, but an angular quantity, which perhaps the vernier is incapable of showing, has been doubled, and may therefore become apparent. As an example, suppose the instrument carefully set over the point A (see Plate 3) and levelled, and observing to D as an initial point, the two verniers are read off, and their position recorded in the field- book. Leaving the lower clamp fast, and releasing the milled-headed serew clamping the vernier plate and that carrying the graduated circle, the point EH is then observed to, and the readings recorded, and so on to the point F. Then leaving the upper clamp fast and releasing the lower, the point D is again referred to, and the operation repeated three times, thus getting four measures for the angles, taking care after the second round to reverse the telescope. This movement will bring the vernier originally on the left hand side of the instrument to the right hand. A mean of the verniers and all the readings is the required angle. Tripods with fine steel points and heavy plum- mets were used as reference marks carefully set over the ends of the base-line. The alignment of the points B and C was very carefully performed, using the telescope in reversed positions, both from the ends of the line and at the points themselves. The triangles obtained by the above operations for fixing EK and F were too small to make it necessary to go into the equation of their conditions. Part II.—Repuctions oF OBSERVATIONS AND CALCULATION OF THE THEORETICAL VELOCITY OF SOUND THROUGH WATER. Distance over which Disturbance Travelled. The distance between the gauges was at first 15,410 cm., it was afterwards 15,840 cm., minus a correction made for the slope of the pile which had been driven slightly out of the vertical. This correc- tion varied between 51 cm. and 59 em., and depended on the depth of the gauge below the top of the pile. Finally in the third position the distance was 18,210 cm. Time Measurements. Let ¢ be the epoch of arrival of the disturbance at gauge A, and let 7,, ¢, be the time constant of the gauge and of the scriber attached to it respectively, then the record on the smoked plate occurs at 516. . Prof. R. Thretfall and Mr. J. F. Adam «On mee time t+7,+0,. Similarly if T be the time required for the transmis- sion of the disturbance, then the second record on the smoked plate occurs at time T+?¢+7),+ 05, where 79, o, are the time-constants of the second gauge and its attached scriber respectively. Thus the observed interval as recorded on the smoked plate is— — D+ 4 + 6g—7,— 9}. Similarly for a disturbance in the opposite direction the recorded interval is— | = T+7, +6, —%%—o, provided that the time of transmission is the same in both directions, and that the time constants of the gauges and scribers have not. altered between the two observations, and that the scribers are attached to the same gauges in the two observations. t+7 os The velocity of transmission calculated on the supposition that: the fork has an exact frequency of 100 must be multiplied by 1°602622—0-0001472 t, to get the correct velocity. The velocities had been originally deduced on the supposition that the fork was correct; these uncorrected velocities are given in Column 9 of the Table; the correction arising from the decimal parts of the above factor, viz., from 0°002622—0-0001472 ¢, are given in Column 10, and the conteed velocities in Column 11. The complete formula for V the velocity is thus— Hence time of transmission of disturbance = ares {1:002622—0-0001472 ¢}, where § is the distance between the gauges and ¢ is the temperature of the fork. This gives the velocity at the temperature of the sea- water during the observation. Theoretical Calculation of the Velocity. In Column 12 of the Table is given the velocity of sound, calculated theoretically as follows. The formula giving the velocity of sound through water is taken to be— es Kg V = Rae where Hg is the adiabatic resilience of volume, and D is the density at the temperature considered. Velocity of Transmission of Disturbances through Sea-water. 517 Observation and Calculation of the Density. In the “Challenger Report,” vol. 1, ‘Physics and Chemistry,’ p. 70 et seqg.,is given a table for calculating the density of a sea- water at any temperature when its density at 15:°56° C. is known. To get the density of the Berry’s Bay water at this temperature six experiments were made on two samples collected at an interval of a month. The water of the Bay is practically Pacific Ocean water, there being to all intents and purposes no fresh water flowing into the Bay. Four of the experiments were made by weighing a piece of glass (Hnglish flint), both in doubly vacuum-distilled water and in the sea-water; and two experiments were made with a specific gravity bottle. Both the glass and the water had been allowed to stand in the balance case for seven hours before weighing; the ther- mometer used was a standard compared at Kew, the correction being, as it happened, zero, for the temperature observed. The piece of glass was suspended from the arm of the balance by a platinum wire, the length of which was 28cm. The weight of 1 metre of the wire was 0°1004 gram, and the density was taken as 21. In each weighing in water one half the wire was immersed. The sensitiveness of the balance was such as to give readings of eight scale divisions per milligram. The density of the sea-water is compared with that of pure water by means of the formula © ar | -w) {1-442 1 ne Ray Lat in which p is the density of the water in which the glass is weighed, G = mass of glass, g = density of glass, W = apparent weight in air, W’= apparent weight in water, o« = density of the air during weighing, B = density of the brass weights = 84, P = mass of platinum wire = 0°028112 gram, p = density of platinum = 21. p on the right-hand side is taken approximately. The above formula is got by neglecting 2 ve i pe MPN eres? SU AD) ecole )B g Pyep compared with W—W'. In the present case this is equivalent to neglecting— 0:00000815 gram in comparison with 4°93 grams. 518 Prof. R. Threlfall and Mr. J. F. Adair. On the By applying the above formula to the weighing in sea-water at 17° C. and to the weighing in pure water at 16:65° C., the first expe- riment gave density of sea-water at 17° = 102702 density of pure water at 16°65°. The density of pure water at the various tempera- tures was taken from Kupffer’s observations as reduced by Professor W. H. Miller (Hverett’s ‘Units and Physical Constants,’ 2nd edition, p. 39). The densities for temperatures intermediate to those given by Everett were obtained by interpolation. For the measurement of the density by means of the specific gravity bottle, two bottles were used, one acting as a counterpoise, together with the small requisite quantity of sand and aluminium foil. The other bottle being quite clean was then filled with the water to be weighed, great care being taken to avoid the retention of any bubble of air. The dry and wet bulb thermometer apparatus was observed, together with the barometer, in order to make the usual corrections for.weighing in air. The results of the two measure- ments made by this method agreed closely with the other four measurements made by weighing glass. In order to have comparable results and to get a mean, the results of the measurements made at 17°, 18°6°, 18°65°, 19°8°, and 21° C. respectively were reduced by “ Challenger Report,” ‘ Physics and Chemistry,’ vol. 1, p. 70, to the temperature 15°56° C. These comparable results are given in the following table. Weights were assigned to the observations as shown. : t Weight Eixperi-| Density at M ae iS ean. assigned to me pb: observation. By weighing glass.. 1 1 -02623 _ ee 2 1 -02629203 1°026271 3 3 3 1 -02629205 i 4 1 -02599 1 -02599 ~4® By sp. gr. bottle 5 1 °02628 ; . 6 102603 1 :026155 i Hence the probable value of the density at 15°56° C. is 1:026116 grams per cubic centimetre. The densities of the water at the various temperatures of the experiments at the Bay were thence found by means of the table in the ‘‘ Challenger Report.” The temperatures of the water in the Bay during the experiments were— * The high weights assigned to this observation are because the weighings were taken at midnight. Velocity of Transmission of Disturbances through Sea-water. 519 13°, 15°5°, 13°3°, 18°4°, Looe LO, 135°, Vise 141°, 143°, 17°6°, 18°, 145°, 15-2°, 18°5°, 20°C. 15°3°, The densities are calculated for these temperatures, and also for 0°1° below and above each. This was done in order to find the coefficient of expansion of the sea-water, since this occurs in getting the adiabatic resilience from the isothermal resilience. The result is as follows :— Temperature. Density. Temperature. Density. 2:9" 1026676 15°7° 1:026086 13:0 1:0266567 158 1:026056 13°1 1026636 15°9 1:026036 13:2 1026616 16:0 1:626016 133 1:026596 16-1 1:025996 13°4 1:026576 ie:9 1025806 13°5 1:026556 17-0 10257856 13°6 1-026536 Ia — 1:0257656 14:0 1:026456 17-4 1:0256855 141 1:026436 175 1:0256655 14°2 1:026416 LES 10256355 143 1-026386 ie-7 1-:0256154 14-4 1:026366 179 10255554 145 1:026346 18°0 1-0255353 14°6 1:026326 18°1 10255053 15:1 1°026216 18°4 1°0254352 15°2 1026196 18°5 1:0254052 15°3 1026176 18°6 1:0253852 15°4 1:026156 19°9 1:0250449 15°5 1:026126 20:0 10250149 15°6 1026106 20-1 10249949 These values give the mean coefficient of expansion 0°000221 per degree of temperature between 12°9° and 20°1° C. Determination of the Resilience. In accordance with the laws of thermodynamics, the adiabatic resilience Hy is taken to be “Eo, where cp, c) are the specific heats Cy at constant pressure and constant volume respectively, and He is the isothermal resilience. Determination of the Ratio of the Specific Heats. The ratio cp+c, is found as in Clausius (‘Translation,’ p. 181), where it is shown that 520 Prof. R. Threlfall and Mr. J. F. Adair. On the Ea) Tia dt Co = Cor ip e Ap dp Here T is the absolute temperature and J is Joule’s equivalent. The equation may be written— | (; oy 2 Cee aur 0 wv dp in which bdo is the coefficient of expansion, and 1 dg with a v at v da negative sign is the isothermal compressibility, or the reciprocal of the isothermal resilience. Thus @ = Me rake if e denote the coefficient of expansion, and Cy pL Kee? J¢p.D D the density which is put for ©. Vv Thus it is requisite to know ¢,, the specific heat, besides the quan- tities represented by the other letters. With a view to obtaining c,, it was discovered from Watts’s ‘Dictionary of Chemistry,’ vol. 5, p. 1017, that the composition of Pacific Ocean water at a depth of 11 feet, Lat. 25° 11’ S., Long. 93° 24 W., is— IN Biche sce pope 10261°9 parts in 1,000,000. 6] Mgrs eS aes 18949°7 Bs SO. shal athens 2786°4 rs Migr saeco tenes: 131571 2 Ke tae viens Be 603°8 95 Cay. See 471:9 Behar Soe, 310°2 3 making the total solid content 3°47 per cent. approximately. Again, in vol. 7, 2nd Supplement, p. 598, it 1s stated that a solution NaCl+100H,O has a specific heat 0:°962, with a specific gravity 1:0234; and this solution contains approximately 3:14 per cent. solid matter. Thus, since ¢) occurs in a small term, it may be taken without much error = 0-962. An experiment made by Mr. Flint, one of the students in the Laboratory, gave a value practically the same as the value here taken. The value of e has been previously found to be 0:000221. J is taken 42 x 10°, and D the density given in the Table. Velocity of Transmission of Disturbances through Sea-water. 521 Determination of the Isothermal Resiliences. With regard to Es, Professor Tait has kindly supplied us with information. He gives formule for the compressibility of fresh water and of sea-water at low pressures and high pressures. The compressibility, as given by him, is a function of the pressure and the temperature, and thus for a pressure which varies rapidly from a low value to such a great value as one or three tons weight per square inch, the compressibility would be a variable quantity. It did not appear at first whether his formula for moderately low pressures, or the formula for such pressures as from one to three tons per square inch, was to be used to get Ho, the reciprocal of the compressibility. The further uncertainty as to the effect of viscosity is not allowed for in finding the theoretical velocity. With a view to settle which of Tait’s formule was to be adopted, it was remarked that for an incom- pressible uniform liquid, subject to impulsive pressures, the equation to determine the impulsive pressure at any point is (Lamb, p. 12)— Cae a dew dx? ' dy? ' de And hence, for an impulsive pressure uniformly distributed over a sphere, the impulsive pressure at a point outside the sphere would be inversely proportional to the distance at that point from the centre of sphere. It seems desirable to determine the function a of a, y, z, and t, which will satisfy given boundary conditions and the equation dp @aw daw dew _ (eae bee a arising from the equation of continuity combined with the equations of impulses, when a relation is assumed between p and w. If itis supposed that impulsive pressure 1s subject to the laws of ordinary pressure, such a relation as that given by Van der Waals might perhaps be taken, or one of Tait’s relations giving the compressibility as a function of pressure and temperature. Supposing that the above consideration approximately applies to - sea-water, it was further concluded, by the method of Berthelot in discussing the experiments of Sarrau and Vieille, that in our case the initial pressure on the walls of the case containing the explosive was in each case (guncotton and dynamite) about 8000 kilograms weight per sq.cm. This agreement between the initial pressure due to gun- cotton and that due to dynamite is accounted for by the density of charge being rather different in the two cases. Supposing this pressure uniformly distributed over a sphere of 1 foot diameter, 522 Proto Threltall and Mr. J. F. Adair. On the which is very much greater than the volume actually occupied by the explosive, and that the pressure at a distant point is inversely propor- tional to the distance from the centre of the sphere, the pressure at 20 yards distant would be approximately 64-4 atmospheres of 1,014,412 dynes per sq. cm. each. This value for an atmosphere has been taken as representing Tait’s value, which he defines by 152°3 atmospheres = 1 ton weight per square inch, at Hdinburgh (?). For pressures considerably below this, Tait’s low pressure formula is applicable. If the sphere supposed to be occupied by the explosive is less than 1 foot in diameter, the pressure at a distant point would, on the above suppositions, be proportionately diminished; and at greater distance than 20 yards it would be further proportionately diminished. Viscosity would aid in further diminishing the pressure, so that on the whole, for the space between the gauges, it seemed advisable to use the low pressure formula as given by Tait. This formula is— Average compressibility of sea-water at low pressures is 481 x 10-7— 340 x 107° ¢+3x 10-9 # per atmosphere increase of pressure at temperature ¢, 152°3 atmo- spheres being = | ton weight per square inch. Taking such an atmosphere as 1,014,412 dynes per sq. cm., we thus get— 1014412 | Livi — pee Sete eee eT Ne chet Sere ee Ree ety ° 481 x 10-7 — 340 x 10-943 X10 P The following table gives the values of this for the temperatures of the observations. Coefficient. of Coefficient of Temperature. resilience, He. Temperature. resilience, He. 13°0 2°2957 x 1010 15°5 2°3293 x 1010 13°3 2°2998 15°8 2°3332 13:4 2°3011 16:0 2°3358 13°5 2°3025 17:0 2°3489 14:1 2°3106 17°5 2°3553 14°3 2°3133 17-6 2°3566 145 3°3160 18:0 2°3617 15°2 2°3258 18°5 23681 15°3 2°3266 20°0 2°3868 General Formula for the Velocity of Sound. The formula on p. 516 thus becomes— i Velocity = a/ pr me ; Ey Je Velocity of Transmission of Disturbances through Sea-water. 523 or, substituting the values already found for sea-water, Velocity = 1 A) pei X10-7—340 x 10-9 ¢+3 x 10-9 ey (273 + ¢) (000221)? , 1014412 42, x 108 x -962 As stated before, the velocities thus calculated are given in column 12 of the general table. The calculation is laborious. _ Haplanation of the General Table. The Table explains itself except with regard to the observations on July 11, and the three first on August 10. In these cases a mean of three intervals was taken by taking a mean of two shots in the direction left to right, and then a mean between: that mean and the interval from right to left. It is to be remarked that in the case of the pair of shots on September 13, which gave the mean interval 0:1277, the mark on the smoked plate determining the single interval 0°1210 was extremely faint. A photograph of this plate is shown (p. 524), the single radial line showing the slight break in the line traced by the seriber. On the lower part of the General Table are given the observations from which a mean interval could not be obtained, together with the first observations on April 25 and May 7,-and another pair of ob- servations on'July 5. These observations were rejected on account of the gauge having been water-logged ; besides this they should be regarded with suspicion, since they would give results whose departure from the final: mean would be greater than the ‘‘ maximum error’ found in accordance’ with the theory of adjustment of observations. It may be added that as a general result of our experience we found that (possibly owing to some interference effects) the distant gauge was often more violently affected after its first indication. Now when the gauges were water-logged they became: deficient in sensitiveness, and consequently in the observations referred to the probability is that the mark observed corresponded to the second, not _the first shock. This conclusion is strengthened by a reference to the photograph of the plate of September 18. .. Parr IIIl.—Repuction anp Discussion or ReEsutts,. The experiments are divided into four classes, according to the nature and quantity of the explosive used. In Class A the explosive was a 9-oz. disk of guncotton, in Class B 10 oz. of dynamite, in Ulass C 18 oz. of guncotton, and in Class’‘D;.4 lb. of guncotton. In Mr. J. F. Adair. On the Prof. R. Threlfall and 524 . Pe en 91 wee Ip 9.9) “sor }, | nes Bana ote oe LIL GER 12H as 029 egy ern, Reg ig eels ea OP / ages | é eee “J aoe 2p 2 pee SRS vo : By Peat pe SINS gp Ny RT ar hae Velocity of Transmission of Disturbances through Sea-water. 526 Prof. R. Threlfall and Mr. J. F. Adair. On the Class A the velocity seems to increase with the temperature, but no such law was detected in the other classes. In order to reduce the observed velocities (when corrected for the temperature of the fork) to a comparable state, they are reduced to one temperature; and in the absence of a rule for doing this it is supposed that each velocity in Class A, &c., 1s expressible in the form V, + at, where V, denotes the velocity at some temperature between the extreme temperatures of the observations in Class A, and ¢ is the excess of the temperature of the observation above the chosen temperature. For Class A the temperature chosen was the mean of the temperatures of the observations; this mean is ap- proximately 17°791° C. Hence arises the system of equations ~V,—0191a = 167567 V,—0°191a = 165943 © V,—0°291a = 157308 V,—0°79la = 157791 V,—0°79la = 148804 V,+0°709a = 180697 V,+0°709a = 193839 V,+0°209a = 197940 V.+0°209a = 163439 V,+0:209a = 197540 V,+0°209a = 174601. If the method of least squares be considered applicable,. the equations for the probable values of V, and a are (Stewart and Gee, vol. 1, p. 274): | | 11V,—0:001a = 1905469. : —(0:091)V,+2'5891a = 66858. These give— | a, = 173297, a = 25890. This large value of a will be merely used in getting the probable error of the mean, 7.e., of the above value of V,. If it has a physical meaning it is very noteworthy. Substituting the value 25890 for a in the foregoing equations there arise the values :—’* Departure from mean. V, = 172512 715 170888 wars 8 — 2339 164842 +S ee BBE» 178270 7 +5043 V6O888 Velocity of Transmission of Disturbances through Sea-water. 527 Departure from mean. V, = 16234] —~ 10886 175483 + 2256 192529 + 19302 158028 —15199 192129 + 18902 169190 — 4037 Mean = 173227, approximately as above. By Bessel’s formula, probable error of mean = 0-6745 Nae of square of departures mere yi 10x11 By Peters’s formula, probable error of mean = 2212, Thus the result for Class A may be written— Probable velocity at 17°79° C. = 1732+22 metres per second. The theoretical velocity of sound is 1523 metres per second. Treating Class B similarly, the mean temperature of the observa- tions is 14°546°C. For convenience of calculation Vz is taken to be the velocity at 14°5°, and the system of resulting equations is :— Temp. of water. 145° O. Vi 4Os ce 156990 148 V_+0°3b = 170198 - 13:0 Vo debe 149956 13:0 Va—1:bb x 150393 13:9 V,—06) = 193252 13°3 V,—1-2b = 154059 133 Va—12b = 154965 13:3 V_—1-Bb = 152420 133 Ve—12) = 155116 13°5 V,—1:00 = 175264 13°4 Vp—l1b = 191406 13°4 Vp—L ll = 188662 15°8 Vptl0b = 214710 15'5 Vp+10b = 195989 155 Vy tL0b = 212728 Lp V,+1-0b = 198361 15-2 Vp +0°7b = 201076 15:2 V,+0°7b = 180730 15-2 V_t0-7b = 199025 152 VptO0'7b = 179417 16-0 Vp +15) = 186556 hm 2 VOL. XLVI. 528 Prof. R. Threlfall and’Mr. J. F: Adair. On the - Temp. of water. 160 7 Vet15b = 142538 15:8 Vzt1'3b = 192178 15°8 V,t13b = 174657 The equations for the probable values of V, and b are— { 24V_+ 11b = 4269946, and LJV,+27:976 = 476912. Hence Vz = 177453, b == 10072. The smallness of b compared with a, the corresponding quantity in Class A, may perhaps be referred to the greater number of observa- tions in Class B; yet it would not seem to represent the real increase of velocity due to an increase of 1° of temperature. In order to get the probable error of the mean, viz., 177453, using the above value of 6, the above equations become— Departure from mean. V, = 156990 — 20463 167176 —10277 164364 — 13089 165501 —11952 199295 + 21842 166145 — 11308 167051 —10402 164506 — 1294.7 167202 —10251 185336 +7883 202485 + 26032 199741 + 22988 204638 + 27185 185917 + 8464 202656 + 25203 188289 + 10836 194026 +16573 173680 —3773 191975 +14522 172367 — 5086 171448 ~ — 6005 127437 — 50023 179084 +1631 161563 —15890 Mean as before .... 177453. Probable error of mean (Peters’s) = 26065. Velocity of Transmission of Disturbances through Sea-water. 529 Thus the result of Class B may be expressed— Probable value of velocity at 145° C = 1775+27 metres per second. The theoretical velocity of sound is 1508 metres per second. For Class C the mean temperature is 18°3° C. Using Vg to repre- sent the velocity at 183°, and c being a quantity similar to the quantity a in Class A, the system of resulting equations is— Vo—0°3c = 197354 Vo—0°3¢ = 199519 Vo t0:2c = 192756 Vo +0:2c = 193659 Vo+0-2¢ = 187674 Hence probable value of Vp = 194192, c= —14147. Substituting this value of c above, the values are— Departure from mean. Wig = adie —1082 195275 +1083 195585 +1393 196488 +2296 190503 —3689 Mean as above = 194192 , If the method of least squares be applicable to such a small number of values, then probable error of mean (Bessel) = 726; or by Peters’s formula probable error of mean = 807. Thus the result of Class C may be written— Probable velocity at 18°3° C. = 1942+8 metres per second. The theoretical velocity of sound is 1525 metres per second. For Class D, reducing the values to 19° C., the equations become— [ Vp = 210000 Vp = 192568 Vptda = 192327 Hence probable value of Vp = 201284 ” ” d = —8957 The values of Vp are therefore— 2Nn 2 530 Prof. R. Threlfall and Mr. J. F. Adair. On the Departure from mean. ae — = Vp = 210000 48716 192568 — 8716 201284 0) : Mean as abore = 201284 | Hence probable error of mean (Peters) = 3474 >) 09 5 (Bessel) = 3394 Thus the result of Class D may be written— Probable velocity at 19° C. = 2013+35 metres per second. The theoretical velocity of sound is 1528 metres per second. Thus in each class the experimental velocity is greater than the theoretical velocity of sound. During the experiments it sometimes occurred that the firing buoy drifted slightly (by influence of wind and tide) from the ne con- taining the piles. The deviation from that line could only be approximately estimated, but it was judged that it was never so much as 3°5 metres, although it was usually slightly out of line. Snppose its distance from the line of the piles to be 3°5 metres, and that the deviation at the other end was the same, then (see figure) taking the distances as marked, A and B being the piles, P the firing point, if the explosion occurs at time ¢, and if V be the velocity of transmission of the disturbance, this reaches A at time t+ a and reaches B at time ¢ + —s and the first interval recorded on the smoked plate is BE = AP 7 = pera E +7)+0)— T=). The second interval of the shot from P’ is , AP’—BP’ 7 = Cerra $71 Fy — 72 — 6p. Hence, if BP—AP = AP’—BP*, 7+7_ BP— AP 2) Te a eae at Velocity of Transmission of Disturbances through Sea-water. 531 and But the velocity, calculated on supposition of the firing point being in line, 1s ; yi= ans (2 7 a+ B PY LBPIAP Lsinacsug ee) CAR eo yen a ae 9g From the figure tan « = = tans = ee Poa == 3° 39". 9" f= 22) 20" 0= 7 36 49°, .and = = 0°99863 = 1—0-00137. Thus the true velocity V is less than the velocity calculated in the General Table by 0-137 per cent. of the velocity in the Table. This amounts to— For the mean of Class A, viz , 1732 metres, the correction is 2°37 metres. 33 33 5b, b}) 1775 ” 39 2°43 op) bie) 3” C, 33 1942 33 99 2°66 bb) x9 3 Dy yy SOS ) 35 2°76 9 Suppose the firing point distant 1°5 metre out of line, a similar calculation shows the correction to the velocity in the Table to be 000026 of that velocity or 0:026 per cent. For the mean velocity of Class A this correction is 0°45 metre. 2? > B 99 O'46 9? 993 bb) C be) 0°50 ) 99 2 D 9 O02 99 It is probable that in general the firing buoy was not anything like a metre out of line, and hence it is clear that it is useless to apply this correction to the observed velocities. In any case a glance at the Table will show that the irregularities observed are of such an order as render any attempt to adjust the observations in this respect of purely fictitious value. On iS) WX Prof. R. Threlfall and Mr. J. F. Adair. On the Discussion oF RESULTS. It will be convenient to collect here the main results of the in- vestigation as far as the comparison with the velocity of sound is concerned. Table of Comparison. * Description Oe aia oor g Velocity Velocity of | Excess of velocity Class. of explo- an aa comparison found (pro- | sound calcu- found over : sive. (complete). Saanade: bable). lated. velocity of sound. met. per sec. | met. per sec. per cent. YA icok canes 9 oz. of dry 11 17°79° C. 1732 + 22 1523 13°75 guncot- ton eee 10 oz. No-| 24 14°5°C. 1775 + 27 1508 17°7 bel’'s No.1 dynamite Cheer 18 oz. dry 5 18532C: 1942 + 8 1525 27°3 guncot- | ton Dc sceass 64 oz. dry 3 19°C. 2013 + 35 1528 31°7 guncot- ton Though the regularity of the mean results is very satisfactory, a glance at any of the Tables will show that several individual observa- tions deviate to the extent of nearly 2 percent. Now from our appara- tus, and from the fact that the observations are to a great extent made automatically, we are at a loss to account for these deviations, unless they are real. We hope to be able to show the cause of this imme- diately, for the moment we wish to add a little to what has already been said as to the rejection of certain observations. When we first began to get readings our gauges were not nearly so satisfactory as they afterwards became; the sensitiveness was sometimes so small that we occasionally failed in obtaining any record whatever from the apparatus which was furthest away from the firing point. The gauges were also apt to allow water to leak in at the bottom, and the air sometimes escaped slightly at the top, allowing the rubber faces to collapse. Both these accidents tend to lessen the sensitiveness of the gauges very materially. It was soon noticed that the abnormal results—and these always occurred in the direction of making the velocity too small—were obtained when the gauges were for some reason or other more or less out of order. When, as shortly occurred, we succeeded in making the gauges uniformly sensitive, and prevent- ing water-logging and the escape of air, we got no abnormal times. The only difficulty we experienced in deciding to reject certain obser- * Kach experiment requires two separate explosions and time-measurements. ) Velocity of Transmission of Disturbances through Sea-water. 533. vations lay in the fact that at first we could see no reason why, if the gauges worked at all, they should give results which differed. We could not see that the introduction of water, for instance, between the rubber faces ought to make the time-constant of the gauge greater— and yet at first we could only explain the abnormal low velocities by supposing that the time-constants were enormously increased at the further stations. A fortunate observation, however, on September 13th, put us on the right track. We had noticed on several occasions that the first mark made by the scriber on the smoked plates was not nearly so strong as the second or third. These marks did not depend in any way on the natural period of vibration of the scriber, for that was far too short, and hence we put them down to the passage up aud down the air-tube of the gauge of pressure waves. It was not yet clear, however, why it was that sometimes the second and third marks of the scriber were stronger than the first. The strength or distinctness of these marks clearly depends on the conductivity and duration of the contact effected in the gauge head ; and this must depend on the increase of pressure and on its duration in the water in the neighbotrhood of the rubber disks. Now it is probable that several waves and not a single wave of compression start from an explosive centre. First there is the sudden expansion by the explosion, then the cooling or escape of the gases and the con- sequent falling together of the water before the disturbance sub- sides. A glance at the map will show that our gauges were so situated with respect to the sheer stone wall of the quay that interference might well be looked for. Supposing then that interference takes place at the further gauge between the direct and reflected waves; it is clear that the first pressure to which the gauge is exposed is not necessarily the strongest, and equally clear that the duration of the interference pressure may be longer, but cannot very well be shorter than that of the pressure first arriving. It may well happen, there- fore, that the second or third marking on the plate is the most distinct, or, even if the sensitiveness of the gauge is low, the first mark might be suppressed entirely, and the second appear alone in its stead. Now, the distance from the first to the second marking on the plate was pretty constant so long as the conditions of the experiment remained the same, and, strangely enough, as it then seemed to us in the case of the abnormal results referred to, there was also a certain agreement. It seemed as if the velocity was either a good deal greater than the velocity of sound—or else a good deal less; the abnormal velocities were consistent with themselves in a rough way. On September 13th, however, we found out the reason —on that day we got a record in which the first motion of the scriber (giving a normal time) was all but too small for detection— ; 534 Prof. R. Threlfall and Mr. J. F. Adair. On the while a little further on there was a strong mark giving one of the usual abnormal times. The result was that we obtained a normal observation, but we saw that had the gauge been slightly less sensitive, or the explosion shghtly smaller, we should have had an abnormal observation. Im order to obtain every satisfaction on this point, we applied (during the reduction of the observations) the mathematical criteria of rejection, atid found that we should thus reject those observations and those only which we had already decidsd to reject on experi- mental grounds. Altogether we rejected three experiments, involving six shots, out of forty-six experiments involving ninety-two shots. We how pass on to discuss the smaller variations in the observations which we retain. It will be remembered that at first our primary object in undertaking this work was to find whether there were any great irregularities or not, with a view to finding whether the ‘directed action” already commented on existed to any great extent. If it did, we hoped to find cet The. deviations in the velocity, principally above the mean. The result has shown, however, that while such irregularities da certainly exist to a slight extent, we have no evidence to show that directed action takes place from the explosion of freely suspended cartridges. The result would probably have been different if we had endeavoured to produce such directed action by the appliation of properly disposed obstacles or air spaces round the detonating point. We think that the small deviations, such as they are, are real, and do not depend on the gauges or chronograph, and certainly not on our measurement of the plates, which was always pushed to a much higher degree of certainty. It seetns probable to us that though the ditccted action is small, it exists to some extent. The observations themselves afford strong proof of the fact that waves of great energy travel faster than sound, and, indeed, in free water, at all events (and, of course, we have no opinion beyond), the velocity is greater the ereater the amount of energy transmitted. If it happens, therefore, that in any experiment the direction of greatest action coimeides with the line passing from the shot through the two stations, we shall have that explosion register an abnormally high velocity. On the contrary, if the energy escapes away from the piles, we shall get a velocity correspondingly low. In intermediate directions of escape, the velocity will be intermediate. A somewhat delicate question presents itself as to the precise method by which these big waves may be considered to become extinguished. A preliminary question which might very well be asked would be as to whether the increase in the velocity is to be looked for as depending on a greatly increased adiabatic resilience. We do not think that any probable change in the resilience would Gages F : Proc. Roy. Sow. Vol. 46. Plate 3. 8 | “ 5 3 x ae a he : W Nee Kone @ig---- sau WA 0G 4 q APH FYOY FO Joes U2 topo, OY 40 YAGa— YH MoYs SuequTaUL oY, : 629 : Blo nosy Aog ‘hog skuwag uw send om jo sdoz ay uw % < Seaids oma UseMzeq wf hf 27ST EY? bruyprUi 10) POYZOUL brnmoys HOLA iS * oe ee] wn _Threfall & Aolawr Proc. ae i Sr aaa aaa aly = Ws -_ B, mal, Yl LiL Ye LE Goo - \K | Se Y | = AELUEDEL ii EEVLEVACTOCUEUOUELE CAUCUS DOLITEELEL SECURE! = LONGITUDINAL SECTION. THROUGH TOP. Roy. Soe. Vol. 46, Plute 4. FEET A INCHES. (4 0 INCHES I2 ( SIDE ELEVATION. West, Newman, lith. SECTION atAA. Velocity of Transmission of Disturbances through Sea-water. 535 account for our results—nor, indeed, would this view be consistent with the remarks made on the subject of choosing Tait’s formule. On the other hand, we have reasons for thinking that after the pressure increases beyond a certain point, the resilience may increase with very great rapidity; if this is the case, it will explain our results, the wave would rush past the first gauge, and then slow down with comparative suddenness. It may be remembered that with respect to Class A, there was some evidence in tavour of thinking that the velocity depends largely on the temperature of the water; this conclusion was not borne out by Class B, where the temperature was slightly higher. Without pretending to say that the evidence advanced is of any real import- ance, depending as it does on single observations encumbered with their private peculiarities, we may note that it would not be at all unlikely for velocities measured as we measured these to have large positive temperature coeflicients. There is every reason to suppose that under the conditions of our experiments the viscosity of the water will be an important factor in determining the rate of decay of the disturbance as it is propagated outwards. Now, of all the physical properties of water, viscosity is the one which varies most rapidly with temperature, and, consequently, it is not unlikely that the decay of amplitude, and hence velocity in the disturbance, may depend to a great extent on the temperature. In addition to the wave of great amplitude whose velocity has formed the subject of this paper, there are, in all probability, waves of varying degrees of amplitude and velocity resulting from the explosion. These waves, together with the final group, having practically the velocity of sound do not, at present, present any teatures of particular interest 536 Prof. Rk. Threlfall and Mr. J. F. Adair. Date of observation. July 26.. a@ececeeoe ee ee we ceoceeo oe ee ee ee Left to right. Right to left. Left to right. oe) ~@ ee ee 3) Aug.1 .. 33 Aug. 10. Ah eae ne «> e©e oe veeeae Left to right Right to left Left to right 2. Nature and quantity of ex- plosive. , 9-oz. disk of gun- cotton. 3. Tempera- | Temperature | Distance be- tween tops ture of the fork. 15-2" CG: On se 4. of the water. 17°6°C. 5. of piles. cm. 15410 General 6. Correction due to slope of pile. Sy pT Gaeta Son ek «salle ain ih eal | | | re 8. ' Observed time | Mean of two | : | interval. ' | eooeeseeoeoeoococooooseoosoosososrsooseosee2sseoeeoeoeoeooooseososo (on) Cw Ore (1) ye intervals. . f és ; xe) iz) To) © © (oo) on) © i=) (on) oO A cS fl 5 & oo) we) bo bo OU @ j=) (<3) (ze) (=) pa 9. Uncorrected velocity. 148745 180834: 193930 198150 174760 156948 170140 149159 150295 193158 1538961 154867 152326 191285 188542 214741 10. Correction due to fork. Is Velocity corrected for temperature ot fork. 165943 157308 157791 148804 180697 193839 197940 1634359 197540 174601 170198 149256 150393 193252 154059 154965 152420 155116 175264 191406 188662 214710 12. Caleulated velocity. 1&2196 3) 152152 151934 33 152589 150943 150117 150848 150302 2 151263 538 Date of observation. Sept. 10. 3) 2) 3) 39 39 3) Sept. 13. 3 3) 3? Sept. 23. 1B eeere ee R. Threlfall and Me, J. F. Adair. Gn Mee 2. Nature and quantity of ex- plosive. Dynamite, 10 oz. 3) 33 39 >” ” ” > bP) 3) bP) Guncotton, 18 oz. 99 39 oP] bh) Guncotton, 4 lbs. 39 3) 3) 99 ) 3. 4. Tempera- | Temperature ture of the fork. 175° of the water. een eer eS 5: Distance be- tween tops of piles. General 6. Correction due to slope of pile. 0 ” ge ” iy i a9 39 Sy st 59 Velocity of Transmission of Disturbances through Sea-water. 539 Table— (continued). a 8. 9. 10. | ae ; 12, Observed time | Mean of two| Uncorrected | Correction Nae come tae Calculated : : : std or temperature ; interval. intervals. velocity. | due to fork. velocity. of fork. 0 :0980 Sha tina! oa } 0-0929 196017 —28 195989 151263 0 ‘0807 NSE = 00927 anh : 6°0508 } 0 0918 198366 —5 198361 : 00912 | Otese \ 0 0906 200998 +83 201076 151128 0-0906 4 a | o100R || 18085 +75 180730 4 0 0932 0 -0898 i 0°0915 199016 +9 199025 if 0 0933 ae ie 4 0-1019 7 Te aa | 0 -0933 } 0°0976 186578 —22 186556 151487 phon 0-127 142600 7 142583 0-13438 i = > 0 -0946 0:0948 } 0° 0947 192291 —113 192178 151397 0 -0950 0° 1133 } 0-1042 | 174760 —103 174657 f, 0 -0918 : 00906 } o,0ot Ie 1996 qr —152 199519 5 Wieiiod 009433 | 193048 — 290 192756 152589 0097555 0 -090227 0 -09389 193950 — 291 193659 *: 0° 101838 0:091994 0 09692 187887 —213 187674 0079074. d , 0 094150 0° 0866] 210253 — 253 210000 152802 0097445 0+091448° 0°09445 192800 — 232 192568 4 0 -097873 0091343 009461 192474 —147 192327 153228 d40 '.. Prof. R. Threlfall and Mr. J. F. Adair. On the Other Observations from which Mean Intervals of see a 1. 2. 3. 4. 5. 6. Nature and Tempera- | Temperature} Distance be- es Date of observation. uantity of ex- ture of of the tween to ats 4 u ay is lope of plosive. the fork. water. of piles. bs pile. cm. PACT IAD). eiaieeeialsjereve ee] AUNCOLLON, NO) OZ. issih 17 °6° - 15410 a) om) Pano DO Bd 5009 ” 9 ” 9 ry) May 7. Left to right. . 5; i. os ;, ‘ Right to left. ~ - $3 i 2 Right to left. yy 29 ” ” ” Ih, DP Se coodco demos || Dyenenamerey 10) ey7, 16° 14.°5 15840 —51 ‘3 Bd donee teracrtnete war a 5 3 ‘ < July 7. No record on o a - far gauge July 11. No record on a a gauge : July 13. No record... * Sis ie Fe ol Da ERS Ae At i 16 14°3 15840 25 C No record... » oF aS - a No record... * a6 53 54 5: i No record... i, be Bc 55 ws * No record... Ee atc fs ae abe UU PAGR as aoran Gdidea us 13 °4° 133° 15840 —59 3 Record lost by Ss os a a ws smudging Aug.1. Norecord... % sis ae ae hd sh No record... , a5 oe on AS va No record... = ote 3 a5 Ble eee 0.) Miissiire ji) ae 93 ve ac =e “s | Sept. 13. Guuges read- ‘ 18 °6 16 18210 0 justed | Velocity of Transmission of Disturbances through Seu-water. 541 could not be obtained, and the Rejected Observations. Observed time | Mean of two it: 9. 10. 11. 12. ye Nout commececd Tt aatcuinned for temperature 8. Uncorrected | Correction interval. intervals. Ve velocity. due to fork. Of fon velocity. QSMAIVIOS 1301 "1294 °1632 *1169 1176 °1508 "1268 : OS13 1015 1142 a, | | | nn | | — 542 Drs, T. L. Brunton and A. Macfadyen, ‘The Ferment-action of Bacteria.” By T. LAUDER BRUNTON, M.D., F.R.S., and A. MacrapyEN, M.D., B.Se. Received March 23,—Read April 4, 1889. In the course of the research the following micro-organisms were used :— 1. Koch’s comma spirillum (Fligge, ‘Die Mikro-organismen,’ Leipzig, 1886, p. 334). 2. Finkler’s comma spirillum (Fliigge, ‘Die Mikro-organismen,’ Leipzig, 1886, p. 382). 3. A putrefactive micrococeus. A. Seurf bacillus (Klein). 5. A bacillus isolated from milk by Dr. Klein, which for con-— venience we may call the ‘‘ Welford Bacillus.” All of these liquefy gelatine, the two last most energetically. Anthrax was not used, on account of the resistance of its spores and the consequent difficulty of completely sterilising the culture media. The experiments were made in each case with pure cultures. The first question which we tried to solve was, What. is the nature of the substance by which bacteria liquefy gelatine? Is itan enzyme? There are two ways in which they might do this. They might secrete some fluid which would dissolve the gelatine mechanically, without altering it chemically, as saliva dissolves sugar in the mouth; or they might do it by secreting a specific enzyme, which would dissolve the gelatine by altering it chemically, as the ptyalin of the saliva effects the solution of starch. If the solution were effected in the first way by the secretion of a. mere solvent, we should expect that when the microbes were removed or destroyed, either by heat or chemical means, the portion of the medium already dissolved would not have any extensive action on fresh media. Butif it had any such solvent action, it would probably continue after the solution had been heated to a temperature sufficient to destroy the action of an enzyme. If, on the other hand, the microbes liquefied the media by secreting an enzyme, we should expect that the- liquefied portion would probably dissolve a considerable amount of new medium when added to it, but that its solvent action would be arrested by exposure to a temperature sufficient to inhibit enzyme action. The culture medium was made by adding to meat broth: gelatine, 10 per cent.; peptone, 1 per cent.; and sodic chloride, 0°5 per cent. The reaction was rendered faintly alkaline with carbonate of soda. In all the experiments Koch’s methods to ensure sterile media and pure cultures were followed out. The Ferment-action of Bacteria. 543 Tubes of 10 per cent. gelatine were inoculated with the five - mnicrobes, and placed in the incubator at 37° C., with the exception of the putrefactive micrococcus, which was kept at 22° C. When liquefaction was complete the fluid was filtered into sterile tubes, the bacterial deposit being washed with a small quantity of sterile distilled water. Of the filtrate, one, three, and five drops were added respectively to fresh gelatine, and the tubes placed in the incubators as before. The gelatine liquefied, and in all cases bacteria were present. This liquefied gelatine was in its turn taken and subjected to a temperature of 50° C. for one hour. Then one, three, and five drops were added to fresh gelatine. After incubating, some of the cholera comma tubes did not liquefy, but in all cases where liquefaction took place it was due to the active bacteria, as proved by their growth on control plates. The control plates were made by adding a few drops of the liquefied gelatine to fresh gelatine, and pouring it out in a sterile glass dish. After incubating at 22° C., the gelatine was examined microscopically, and the presence or absence of bacterial colonies noted. The liquefied gelatine was next subjected to a temperature of 100° C. for fifteen minutes. The same number of drops were added to gelatine. This fresh gelatine did not liquefy. Finally, 4 c.c. were added to fresh gelatine, but still it did not liquefy. The control plates showed no colonies. We therefore conclude that exposure to a temperature of (I) 100° C. destroys— (a.) The bacteria. (b.) The liquefying power of the fluid. (IT) 50° C. does neither. It was not deemed advisable to continue the sterilisation too long, having regard to the injurious action of heat on soluble ferments. It was next necessary to determine the temperatures between 50° C. and 100° C., which would be sufficient to kill the bacteria without rendering any ferment which might exist inactive. A series of experiments led to the following results :— 60° C. for half an hour killed Koch’s and Finkler’s spirillum. 75° C. for fifteen minutes, on two successive days, killed the scurf and “Welford” bacilli. 70° C. for fifteen minutes, on two successive days, destroyed the putrefactive micrococeus. Having established these facts, a series of cultures at 37° C. were made in small glass flasks, each containing about 100 cc. of 10 per cent. gelatine. The liquefied gelatine was filtered, and the deposit washed with sterile distilled water. ; VOL. XLVI. 2 0 iit 544 Drs. T. L. Brunton and A. Macfadyen. These filtrates from the five series. of cultures were sterilised as described above. Then 5—10 c.c. of each were added to 10 per cent. gelatine (20 c.c.) and kept at 37° C.,as well as control tubes of sterile gelatine. On the third day the tubes were removed from the incubator and placed in ice-cold water. Results :— Scurf bacillus f The gelatine does not stiffen, but remains Welford ecee'y liquid. Koch’s spinllum The gelatme is semi-liquid, and does not Finkler’s ‘eit a completely re-gelatinise. . Putrefactive micrococcus Control gelatine Control plates. No bacteria. Kept at the ordinary room temperature, these phenomena persisted, the liquid gelatine remaining liquid, and the solid gelatine not lique- fying. Here, then, we have complete liquefaction of the gelatine produced in the first two cases, partial hquefaction in the next two, and no effect in the last. | That this liquefaction was brought about withowt the presence of active bacteria is proved by the fact that control plates inoculated from the liquefied gelatine remained sterile. The complete lique- faction was produced by the sterile fluid from the microbes which were more active liquefiers of gelatime than the ethers. In the case of the two comma spirilla the enzyme action in gelatine was evidently more feeble. The negative result with the putrefactive micrococcus, and also the fact that tubes inoculated from it, and kept at the optimum temperature of 22° C., also gave negative results, were probably due to the preliminary sterilisation having destroyed both the microbes and any enzyme which they might have formed. These introductory experiments led to the following conclusions :— 1. 100° ©. destroyed both the bacteria and the liquefying power. 2. 50° destroyed neither the bacteria mor the hquefying power. 3. Temperatures between 60° and 75° C. destroyed the bacteria, but not the liquefying power im four cases. _ 4. The liquefied gelatine treated as under 3, and added to fresh gelatine, liquefied it, although active bacteria were proved to be absent. ©. The liquefaction must, we think, be due to a soluble enzyme, inasmuch as liquefaction still took place after the elimination of the microbes, while it was prevented by exposure to such a temperature as would destroy the aetivity of an enzyme but would not be likely to affect the action of a simple solvent. \ The gelatine stiffens. The Feement-action of Bacteria. D495 iT: Having regard to the fact that the peptonising action in gela- tine was slow, and in two cases partial, it was next sought to de- termine whether more active liquefaction of the gelatine could be obtained by growing the microbes in some other albumenoid soil. Two culture fluids were made with meat broth as follows :— A. Meat broth— B. Meat broth— Peptone, 1 per cent. NaCl 0°5 per cent. Natl 0-5... Both were rendered faintly alkaline with the carbonate of soda. The bacteria grew well in both of these media, and so rapidly and abundantly in B. that further experiments were made with it only, v.e., without peptones. For each culture, 100 c.c. meat broth were used. After inoculation and four days’ incubation at 37° C., the broth was filtered, and the bacterial deposit washed with sterile distilled water. It was then sterilised as already described, and 10 c.c. added to tubes of 10 per cent. gelatine. These tubes were placed in the incubator, as well as control tubes of sterile gelatine. When taken out, and placed in ice-cold water, the following results were obtained :— (1.) After 24 hours: Scurf bacillus \ eral Welford bacillus Koch’s spirillum Hee awe Finkler’s ea Semiliquid. Putrefactive micrococcus Control gelatine Controi plates. No colonies. (2.) After 48 hours : Koch’s spirillum \ Sie Ruliecicrallunh a Putrefactive micrococcus Control gelatine Control plates. No growth. ; No liquefaction. \ No liquefaction. From these experiments it will be seen that the enzyme developed *in meat broth is more active than that formed in gelatine. In twenty-four hours the gelatine was liquefied by the scurf and Welford bacilli ; in forty-eight hours by Koch’s and Finkler’s comma spirilla. Again the putrefactive micrococcus gave negative results. Conclusions :— | 1. An enzyme is formed in meat broth which liquefies gelatine, ee i A Oh re lt Fe 546 Drs. T. L. Brunton and A. Macfadyen. and does so more surely and quickly than the enzyme formed in gelatine itself. 2. The liquefaction is produced by a soluble ferment, since its action can be demonstrated apart from the microbes which pro- duce it. ! 1. Instead of using heat sterilisation some experiments were made with menthol and thymol. It was found that when these substances were added in amounts sufficient to prevent the growth of the bacteria—the ferment action was likewise inhibited. ny. The presence of a soluble ferment being demonstrated, can we isolate it P (1.) From gelatine. (2.) From meat broth. (1.) From Gelatine Cultures. Flasks containing 250 c.c. of 10 per cent. gelatine were inoculated with the five microbes. They were left in the incubator at 47° C., (putrefactive micrococcus, 32° C.), till liquefaction was complete. The liquefied gelatine was treated with absolute alcohol and filtered. The precipitate was extracted with glycerine, and finally repre- cipitated with alcohol. The precipitate, after drying in a sterilised flask, was taken up in a small quantity of sterile distilled water, and allowed to stand over night. About 5 c.c. were then added to 10 per cent. gelatine, and incubated at 37° C. Results —Negative. No liquefaction was produced. (2.) Meat Broth Cultures. In each case 250 c.c. were treated in a similar manner—with alcohol and glycerine, and the precipitate and sterile distilled water added to 10 per cent. gelatine. Results :— Koch’s spirillum Finkler’s spirillum ps liquefaction. Putrefactive micrococcus Scurf bacillus In a few tubes the gelatine was Welford bacillus \ viscid. The rest resolidified. Control plates. No colonies. Concluding that the prolonged method of extraction had weakened The Ferment-action of Bacteria, DAT the action of the enzyme, a modification of the process was next made in the following manner :—500 c.c. of meat broth were inocu- lated with the microbes, and left in the incubator for seven days. The precipitate, with an excess of alcohol, was allowed to stand overnight, and, after drying, was dissolved in sterile distilled water, and then reprecipitated by alcohol. This precipitate was dried and taken up in distilled water. The next day about 20 c.c. were added to 100 c.c. of a 5 per cent. gelatine, and placed in the incubator at ee Oe... Results after four days :— The only positive results were obtained with the scurf bacillus and the Welford bacillus. In these cases the gelatine remained liquid, while the control gelatine resolidified. The control plates gave no colonies. Oonclusion—The bacteria do form a soluble enzyme which can be isolated, and its action demonstrated on albumenoid gelatine. Ne Are the microbes which liquefy gelatine capable of exerting a like action on other proteid bodies ? To test this, experiments were made with— (a.) Egg-albumen. (b.) Fibrin. In the first place, it was necessary to find out what resulted from the direct action of the microbes. Faintly alkaline meat broth, as developing the most active enzyme, was used. (a.) Egg Albwmen. To flasks containing 100 c.c. of meat broth were added small pieces of coagulated egg albumen. The flasks were then sterilised and inoculated with Koch’s spirillum, Finkler’s spirillum, the scurf and Welford bacilli. They were then placed in the incubator at SOs | Results :— (1.) Scurf bacillus. Welford bacillus :— lst day. No marked change. 2nd day. Albumen broken up into small fine flocculent fragments. 3rd day. Disintegration almost complete. 4th day. Disintegration complete. 220. 2 548 Drs. T. L. Brunton and A. Macfadyen. (2.) Koch’s spirillum. Finkler’s spirillum :— 1st day. No marked change. 2nd day. Translucent. ord day. Thinned and transparent. Sth day. Disintegration. The bacteria are therefore able, by means of their Bete action, to disintegrate egg albumen. (b.) Fubrin. To 100 c.c. of the meat broth small pieces of boiled fibrin were added, and after sterilisation the flasks were inoculated with the same microbes, then placed in the incubator at 37° C. Results :—- (1.) Seurf bacillus. Welford bacillus. Ist day. No marked change. 2ndday. Fibrin eroded. ord day. Breaking up. Ath day. Disintegration complete. 5th day. Fluid has become turbid. (2.) Koch’s spirillum. Finkler’s spirillum :— Ist. day. No change. 2nd day. Slight erosion. ard day. Frayed appearance. Ath day. Commencing to break up. | Sth day. Disintegrated. 1 _ 6th day. Turbidity. Conclusion —The bacteria exert a disintegrating action on egg albumen and fibrin, as well as on gelatine. . VI. i Here again we have a marked disintegrating action on fibrin. such as egg albumen and fibrin, in the same way that its action was demonstrated on gelatine ? The alcoholic precipitate from 500 c.c. of the meat broth culture was dried at 35° C., and then dissolved in sterile distilled water. It was then reprecipitated by alcohol and filtered. This precipitate was 1 Can we demonstrate the action of the enzyme on proteid bodies | | dried in sterile plugged flasks, and to it were added 50 c.c. of sterile The Ferment-action of Bacteria. 549 distilled water, and 5 ¢.c. of a § per cent. chloroform water. Car- bonate of soda was finally added to render the fluid faintly alkaline. In each flask was placed a small piece of boiled fibrin. After four days in the incubator they were taken out and examined :— A. From each, gelatine plate cultures were made. B. The appearance of the fibrin was noted. C. After filtration the filtrate was tested for digestive products. A. Some of the plates showed bacteria. The flasks from which these had been made were rejected; only those were used which had remained sterile. B. In none did the fibrin break up and disappear. But it became thinned and frayed at the edges. This was most marked with the scurf and Welford bacilli. C. The filtrate was examined for soluble products : — On neutralising with dilute hydrochloric acid a precipitate ap- peared. This was filtered off and the filtrate tested for peptones. A solution of caustic soda was added, and then a highly dilute solution of cupric sulphate was filtered down the side of the test tube. At the line of demarcation the rose-coloured peptone reaction was strongly — marked. The simple boiled solution of the ferment only gave the faintest peptone reaction. These results were obtained with the scurf and Welford bacilli, and Koch’s and Finkler’s spirillum. To sum up :— 1. The fibrin was visibly affected. 2. Neutralisation produced a precipitate. 3. The peptone reaction was very distinct. The enzyme therefore, apart from the bacteria, can form soluble products from fibrin, and amongst these peptones. VI Are the microbes capable of forming a diastatic, as well as a pep- tonising ferment ? A. Seurf bacillus. Welford bacillus :— Starch was heated with water so as to form a thin paste. To this was added sodic chloride (0°5 per cent.). About 100 c.c. were placed in each flask, which was then plugged with cotton wool and sterilised. After inoculation they were placed in the incubator (37° C.) along with flasks of sterile starch paste. Flasks were opened on successive days and examined :-— } 550 Drs. T. L. Brunton and A. Macfadyen. 2nd day. Starch has lost its opalescence. Iodine gives a blue colour. : 5rd day. J dine gives a red colour. 5th day. No reaction with iodine. 6th day. Was tested for a reducing sugar. The reactions were as follows :— (J.) Iodine.—No reaction. . (2.) Caustic soda.—On gently boiling fluid becomes yellow. (3.) Cupric sulphate and caustic soda.—A_ yellow precipitate on boiling. | (4.) Fehling’s reagent.—A red precipitate. (5.) Barfoed’s reagent.—No reaction on gently heating. (Barfoed’s Soiution :—One part of neutral acetate of copper dissolved in 15 parts of water, and then to 200 ec.c., 5 ec. of acetic acid (38 per cent.) added.) The control starch gave blue colour with iodine, but none of the above reactions. B. Putrefactive micrococcus— Results were negative. C. Koch’s spirillum. Finkler’s spirillum :— The same starch solution was used, but a few drops of meat broth were added in each case. The usual control experiments were made :— 3rd day. Starch has lo: t its opalescence. Iodine strikes a blue colour. 4th day. Iodine gives a violet colour. 5th day. Jodine gives red reaction. 7th day. lIodine-—Red. Caustic soda.—Yellow on boiling. Cupric sulphate and caustic soda.—No reduction. Fehling’s solution.—No reduction. On previous addi- tion of H,SQO, a slight reduction. Barfoed’s reagent.—No reduction. Control starch.—Iodine strikes blue. From these experiments the following conclusions may be drawn :— 1. The putrefactive micrococcus did not grow on the carbohydrate soil, and so we are left in doubt as to its diastatic action. 2. The scurf bacillus and Welford bacillus were both capable of cultivation, and evinced a marked diastatic action, in addition to their peptonising power. The failure of the iodine test, and the The Ferment-action of Bacteria. 551 precipitates obtained with Fehling, &c., indicate the presence of a reducing sugar. The failure with Barfoed’s reagent suggests that the sugar is in great part, at any rate, maltose. 3. With regard to Koch’s spirillum and Finkler’s, though they evinced a diastatic action, it was feebler than in the former case, only traces of a reducing sugar being detected after the addition of sulphuric acid. The red and violet coloration with iodine points to the formation of dextrin (erythro- and achroo-dextrin). At any rate, in the scurf and Welford bacilli we have two microbes which evince a marked diastatic action; and a demonstration of the fact that the same germ can produce both a diastatic and a peptenising ferment. Welch Can we demonstrate the action of the diastatic enzyme apart from the bacteria ? Starch cultures of the scurf bacillus and the Welford bacillus (two days’ growth) were treated with chloroform water (1 per cent.) till they became sterile. The fluid was then added to fresh starch, and incubated at 37° C. In eight to ten days the iodine reaction had disappeared. On boiling with caustic soda the fluid became yellow. Fehling’s solution was reduced. The fluid lost its opalescence. Control plates—no growth. These experiments point strongly to the existence of a diastatic enzyme capable of isolation, and of acting apart from the bacteria. IX. That the peptonising enzyme bears the closest analogy to the pancreatic ferment will be seen from the following experiments. Sterile meat broth, in which Finkler’s spirillum and the Welford bacillus had been cultivated, was added to 10 per cent. gelatine tubes of differing reaction :— Gelatine. Results. A. Acidified with dilute hydrochloric acid.. No liquefaction. B. Alkaline by adding sodic carbonate .... Liquefied. Oe oIicimga te aire, 2 2h a Liquefied. D. Boiled after adding the ferment........ No liquefaction. X. The digestive action of the microbes was tested on several other bodies. | i , } ‘it { ' D02 Dis. T. L. Brunton and A. Macfadyen. 1. Fats.—Alkaline meat broth and olive oil, 2 per cent. The results were negative. Experiments which were made by Manfredi* tend to show that: f fat containing media impair the vegetative energy of bacteria. 2. Dextrose-—The culture fluid was prepared as follows :— Dextrose ...... se, 2 per cent. Peptomes cis: sn. ss t ig Sodic chioride .. /.. .@°5-.%, Reaction. .se6.06 . Neutral. After sterilisation, the flasks were inoculated with the scurf bacillus and Welford bacillus. Incubated at 37° C. They were examined on the fourth day. Febling’s solution was no longer reduced. The fluid gave a marked acid reaction. The control solution reduced Fehling’s solution. Reaction was unchanged. 3. Cane-sugar.—Cane-sugar, 2 per cent. Peptone, 1 per cent. NaCl, 0°5 per cent. Reaction, neutral. Inoculated with scurf bacillus and Welford bacillus, and incubated at 37° C. The results were negative. No reducing sugar detected. Muscle.—Alkaline meat broth cultures were used. Inoculated with Finkler’s spirillum and Welford bacillus. With the Welford bacillus a marked effect—the muscular fee becomes disintegrated, and the striz indistinct. These experiments, though incomplete in themselves, are sufficient to show that the bacteria which liquefy gelatine and diastase starch, can also exert a digestive influence on dextrose and muscle. The exact determination of the products of this action in the case of these and some other organic bodies must be reserved for further investigation. To sum up briefly the results of this inquiry :— 1. The bacteria which liquefy gelatine do so by means of a soluble enzyme. 2. This enzyme can be-isolated, and its peptonising action demon- strated apart from the microbes which produce it. 3d. The most active enzyme is that formed in meat broth. 4, Acidity hinders, alkalinity favours its action. 5. The bacteria which form a peptonising enzyme on proteid soil can also produce a diastatic enzyme on carbohydrate soil. * « Accademia dei Lincei, Rendiconti,’ vol. 3, sem. 1, 1887, p. 535. OBITUARY NOTICES OF FELLOWS DECEASED. The Rev. THomas Gaskin, who died at his residence at Cheltenham on February 17th, 1887, was born at Penrith, in Cumberland, in 1810. He was educated at Sedburgh, and for some time before he left was second in the School. On leaving Sedburgh School, in 1827, he proceeded to St. John’s College. One of the men of his year writes that it was understood that he came to Cambridge under the auspices of Lord Brougham, who had formed a very high estimate of his mathematical talent, and was confident he would be Senior Wrangler. Later on, in 1851, Lord Brougham, writing a testimonial for’ Mr. Gaskin, speaks of an intimate acquaintance of above thirty years. On entering St. John’s College, he found the freshmen exception- ally strong in mathematics. The third wrangler of his year was then a Johnian, who afterwards migrated to Caius College. Besides the Senior, there was a fourth man reckoned equally good, whose health broke down under hard reading. Nevertheless, he was always placed first in the College examinations. This position could not be obtained, much less retained, every year, but by the exhibition of considerable classical knowledge. The late Dr. Kennedy, whose lectures he attended, entertained a favourable opinion of his promise as a classi- cal scholar, though his chief attention was then devoted to mathe- matics. It has also been stated on the authority of some of his old schoolfellows, that on leaving Sedburgh he could repeat above twenty Greek plays by heart. He took his degree of B.A. in 1831, as second wrangler and second Smith’s prizeman, a member of his own College being Senior. ,The two were so nearly equal in merit that there was great difficulty in arranging their order. According to the custom of that day, cases of near equality were decided by questions given out orally, one by one, by some competent Master of Arts, not one of the Moderators or Examiners. In such a system a previous accidental acquaintance with the subject matter of a question would make an appreciable difference. Thus their positions in the final list, if decided by an insufficien{ number of questions, might indicate a greater difference _ than really existed. Soon after his degree he was elected Fellow and Tutor of Jesus College, the duties of which responsible position he continued to discharge for eleven years. When, on his marriage, in 1842, he resigned these offices, a subscription was opened among his friends VOL. XLVI. b and pupils, and he was presented with a valuable service of plate, as a testimony of their respect aud esteem. During his twenty years’ residence in the University, he was almost uninterruptedly engaged in preparing pupils for the exami- | nation, and in writing books on subjects connected with their studies. He also during this time served the University in the difficult and responsible office of Proctor. He was six times chosen Moderator, viz., in the years 1835, 1839, 1840, 1842, 1848, and 1851. This is an appointment which no one before him had ever held so often. These repeated re-elections prove the general esteem in which his extra- ordinary power in constructing problems was held. In 1836, Mr. Gaskin was elected a Fellow of the Royal Astrottomical Society, and in 1839 he became a Fellow of the Royal Society. He removed to Cheltenham about 1855, where he spent tlie remainder of his life. During his residence at this place, he occupied himself almost entirely with private pupils until his health failed. He here published a pamphlet on the theory and practice of solitaire. Subkéquently, the broken state of his health, the early deaths of his sons and of his wife, made him choose a retired life, and prevented him from devoting his time to work. He seems never to have been a strong man, for he was an invalid even when Tutor of Jesus College. Mr. Gaskin, when resident in Cambridge, was especially known for his unrivalled skill in the construction and solution of problems, especially such as required the application of complicated analysis. Indeed, we can see by his writings that this was the bent of his talents. In 1847, he published two volumes of “Solutions of Trigo- nometrical and Geometrical Problems.” These were the solutions of examination papers set in St. John’s College for the years 1830 to 1846. Though these books are of an elementary character, yet they must have had considerable influence on the studies of those seeking distinction in the examinations of that day. Hven after this Japse of time, when so many new methods have come into use, a teacher would find here a useful collection of problems and examples with admirable solutions, a store-house from which he might draw material to lighten his own labours. In the appendices, he added the solution of some other geometrical problems which were exciting interest at the time. He also wrote in the ‘Mechanic’s Magazine,’ and in 1848 published some papers on the inscription of polygons in the conic sections. In Dr. Hymer’s treatise on ‘‘ Differential Equations,” we find the solution of one of the problems proposed by him in the Senate House, when Moderator in 1839, given as the best and simplest iW method of solving an important differential equation. This is the equation, a particular case of which occurs in the theory of the figure of the earth. The problems and examples set in the Senate House are generally absorbed into the ordinary text-books, and become the standard examples by which successive generations of students acquire their analytical skill. On looking through Mr. Gaskin’s papers, one cannot help noticing how many of his problems have been taken, and may be recognised as old friends. We thus learn one reason at least why his papers were so popular amongst the older writers. They are on all kinds of subjects, and generally are put in a way which shows that he was always on the look-out for a telling question. It seems to have been his custom to put any new theorem that he discovered in the form of a problem, rather than in that of a paper in a mathe- matical journal. HK. OJ. R. Dr. Artuur Fares, the fifth son of the late Dr. John Richard Farre, was born in 1811, in the house in Charter...use Square in which his father lived and practised for many years. He received his early education at the Charterhouse. In 1827 he became a pupil at St. Bartholomew’s Hospital, and the following year he entered at Caius College, Cambridge. In the intervals of the University terms he prosecuted his medical studies at St. Bartholomew’s. He was a diligent dissector, and as prosector under Abernethy, he prepared subjects for the last course of lectures on physiology delivered by that eminent surgeon. He graduated M.B. at Cambridge at the head of the medical list in 1833, and M.D. in 1841. During 1836-7 Dr. Farre lectured on Comparative Anatomy at St. Bartholomew’s Hospital, in succession to Mr. (now) Sir Richard Owen. From 1888 to 1840 he lectured on Forensic Medicine. Dr. Farre contributed to the ‘Philosophical Transactions’ for 1837 an elaborate paper with numerous lithographic illustrations, entitled ‘Observations on the Minute Structure of the Higher Forms of Polypi, with views of a more natural Arrangement of the Class.” The publication of this paper was followed by his election as a Fellow of the Royal Society in 1839. To the ‘Philosophical Transactions’ for 1843 Dr. Farre contributed a paper “‘ On the Organ of Hearing in the Crustacea.” Dr. Farre’s professional career was determined for him when, in the year 1842, he succeeded Dr. Robert Ferguson in the chair of Obstetric Medicine at King’s College, and at the same time he was appointed Physician Accoucheur to King’s College Hospital. These appoint- ments he retained until 1862, when, on his retirement, he was made Consulting Physician. b 2 Y He became a member of the College of Physicians in 1838, and was elected a Fellow in 1843. He was Censor in 1861-2, and Senior Censor in 1865. In 1872 he delivered the Harveian Oration, taking as his subject ‘‘ Harvey’s Exercises on Generation.” For a period of twenty-four years he held the appointment of Kxaminer in Midwifery at the Royal College of Surgeons. Dr. Farre possessed all the qualities required in a great and suc- cessful obstetric physician, and he soon acquired a large practice amongst the very highest ranks. He attended the Princess of Wales at the birth of all her children. He also attended the late Princess Louis of Hesse Darmstadt, Princess Alice of Great Britain, in her first confinement; also Her Imperial Highness the Duchess of Hdin- burgh, in her first confinement at Buckingham Palace, in 1874, and again at Hastwell Park, in 1875. He attended Princess Christian in 1867, at Windsor Castle, and again in 1869, at Cumberland Lodge. He attended the Princess Mary Adelaide in all her confinements, and the Princess Leiningen in 1863, at Osborne. Few physicians have had the honour to attend successfully so many members of the Royal Family. In 1875 Dr. Farre received the appointment of Physician Extra- ordinary to Her Majesty, and although no word of dissatisfaction ever escaped from him, his friends and professional brethren thought it strange that this should have been the only public royal recognition of his eminent services. After the death of Sir Charles Locock, in 1875, Dr. Farre was made Honorary President of the Obstetrical Society. His chief literary contribution to his own department of medicine was the elaborate article ‘‘ Uterus and its Appendages,” in Todd’s ‘Cyclopedia of Anatomy and Physiology.’ Dr. Robert Barnes - says of this article that it “is the fruit of remarkable labour and original research, digested and set forth with consummate judgment. To this day it stands, if not unrivalled, yet unsurpassed. It is rich in original illustrations, and just in acknowledging what is borrowed. It may be doubted whether any similar work has stood the trying test of time so well. Others may have added to it; few have made corrections that have held their ground.’’* Dr. Farre was one of the founders of the Microscopical Society ; he was its first honorary secretary, and served several times on its council, and in 1851-52 he was its President. Through the influence of the Prince of Wales he obtained for the Society its Royal Charter. He communicated several papers to the Microscopical Society, amongst others the following :—‘‘ On the Minute Structure of certain Substances expelled from the Human Intestine, having the ordinary appearance of shreds of lymph, but consisting entirely of filaments * « Brit. Med. Journal,’ Dec. 24, 1887. ¥ ' of confervoid type, probably belonging to the genus Oscillatoria” (‘ Mic. Soc. Trans.,’ 1, 1844); “An Account of the Dissection of a Human Embryo of about the fourth week of Gestation, with some observations on the early development of the Human Heart” (‘ Mic. Soe. Trans.,’ 3, 1852); ‘‘ Description of an early human Embryo of about the fourth week of Utero-Gestation”’ (‘ Mic. Soc. Trans.,’ 5, 1857). In the ‘ Medical Gazette ’ for 1835 (vol. 17), Dr. Farre published a paper on the ‘Trichina Spiralis.’. In the previous volume of the Gazette the discovery of the parasite is referred to as follows :—“‘ The muscles of bodies dissected at St. Bartholomew’s Hospital had been more than once noticed by Mr. Wormald, the demonstrator, to be beset with minute whitish specks, and their appearance having been again remarked in the body of an Italian aged 45, by Mr. Paget, a student of the hospital (now Sir James Paget), who suspected it to be produced by minute entozoa, the suspicion was found to be correct, and Mr. Owen was furnished with portions of the muscles on which he had made the following observations.” Anaccount is then given of the observations of Professor Owen, who named the parasite Trichina spiralis. A second body infested by this parasite had been observed in the dissecting room of St. Bartholomew’s, within a fortnight after the occurrence of the first, and the object of Dr. Farre’s paper was, as he said, mainly to refer te some points on which he was able to give some additional information, or as to which his observations differed from those of Professor Owen. In particular he had been able to make out in some specimens the existence of a distinct alimentary canal and an ovary. A paper by Dr. Farre “On Diplosoma crenata, an entozoon inhabiting the human bladder, and hitherto often confounded with Spiroptera hominis,’ was published in Beale’s ‘Archives of Medicine,’ vol. 1, p. 290). The article ‘“‘ Worms,” in the ‘ Library of Medicine’ (vol. 5, p. 241), was contributed by Dr. Farre. At a time when Dr. Farre was overworked and harassed by his large practice, he had the great sorrow of losing his wife, and shortly afterwards he sustained a compound dislocation of the ankle, in con- sequence of a fall from a second floor window into the area of his house. The wound gradually healed, and he was able to move about, first with crutches, and then with the help of a stick ; but he remained painfully lame until his death, which occurred on the 17th December, 1887. | Dr. Farre’s lectures and his clinical teaching were highly appre- ciated by his pupils, of whom the writer of this notice had the good fortune to be one. He was a model physician accoucheur, and he acquired the confidence and esteem of the profession through his diagnostic and practical skill, and the high principles and sense of VOL. XLY1. C tear vi honour by which he was guided in all the relations of life. A most charming and genial companion, an affectionate and constant friend, he delighted those who enjoyed the privilege of his society and his generous hospitality by his musical accomplishments, which were of a very high order. Gi: ody Gustav Ropert KircHHorr was born on March 12, 1824, at Konigs- berg. He began his studies in his native town under the direction of F. E. Neumann, and no one who has studied the writings of both these eminent men can fail to notice the great influence which Neumann’s teaching must have had in forming the character of Kirchhoff’s scientific ideas. In 1850 Kirchhoff went as Professor Extraordinarius to Breslau, and in 1854 as Professor of Physics to Heidelberg, where he stayed till 1875. In that year he accepted a chair of Physics in Berlin. Gradually failing in health he had to give up his lectures, and died on October 17, 1887. His writings, the first of which he published at the age of twenty- one, cover nearly the whole range of physics, and there is hardly one of them which has not marked a decided progress in the subject to which it refers. His first paper (1845), treating of plane current sheets, was the first of a series in which he deduced and applied the now well-known equations for the distribution of electric currents in conductors which are not linear. In 1849 an important communication appeared in Poggendorff’s ‘ Annalen,’ in which, for the first time, the resistance of a wire was measured in what is now known as electromagnetic measure. A paper of considerable interest, ‘Ueber die Bewegung der Elektricitat in Leitern,” appeared in the year 1857. The propa- gation of electric effects in wires is discussed in this paper, the principal result being: ‘‘ that the rate of propagation of electric waves is found to be c/./2—that is, independent of the cross section, the coefficient of conductivity of the wire, and the electric density ; the rate is 41,950 (German) miles per second, or very nearly the same as that of the propagation of light.” In view of the important con- clusions to which modern researches in electricity have led, con- siderable historical interest will always attach to the above statement. The remaining electrical papers treat of the oscillating discharge of the Leyden jar, the distribution of electricity on two conducting spheres, and of the capacity of a condenser formed of two parallel circular plates. ) We have next two papers on Magnetism; one (1853) treats of the magnetism induced in an infinitely long cylinder, and the other solves the problem of the magnetisation of an iron ring under the influence Vil. ' of electric currents. A suggestion made in the latter paper to use closed rings of iron for the determination of the coefficient of induc- tion has led, at the hands of Stoletow and Rowland, to important practical results. Kirchhoff's name is most generally known in connexion with his researches on the relation between the absorptive and the emissive properties of bodies. The explanation of the Fraunhofer lines which are derived from these researches, and the work done jointly with Bunsen on the discontinuous spectra of gaseous bodies, gave such an impulse to the study of radiation that a whole science—that of spectrum analysis—developed as a historical sequence to Kirchhoff’s work. Itis acurious instance of an abstruse calculation giving rise to extended experimental Investigations which have in reality very little connexion with it; for it is only a small fraction of spectrum analysis in which the connexion between radiation and absorption is made use of atall. There is really no @ priori reason why we could not have known as much as we do now of the spectra of different bodies without being acquainted with the important law proved by Kirchhoff. A discussion has arisen as to how far Kirchhoff’s work was antici- pated by that of Balfour Stewart. The latter had experimented on the radiation and absorption of heat, and had drawn some important conclusions from his experiments. Stewart’s work is conclusive in showing that if we assume the ratio of the emissive to the absorp- tive power to be the same for all bodies and only a function of the temperature and wave-length, all facts can be satisfactorily accounted for. Kirchhoff, without being acquainted with Stewart’s researches, went further, and proved that the law just stated is the only one consistent with thermodynamical equilibrium. Kirchhoff’s paper has been objected to as being too elaborate in the method of its proof, but no simpler proof has ever been given, and it would be difficult to lay a finger on a single sentence of this classical paper which could be removed or shortened without detriment to the logical sequence of the argument. In connexion with these theoretical researches and in order to trace the existence of terrestrial elements in the sun, Kirchhoff prepared a drawing of the solar spectrum. Unfortunately an arbitrary scale was used, and the prisms were occasionally shifted, so that the map was soon superseded by Angstrom’ s, in which the lines were directly referred to wave-lengths. It seems of interest, however, to point out as a proof of the acuteness of Kirchhoff’s observing power and the perfection of the optical adjustments, that the amount of detail given in his map is exactly that given by calculation as possible with the resolving power which he used. No work could be more trying than that of drawing a map of the solar spectrum reaching the Yul limits of the instrumental powers; Kirchhoff’s eyes suffered in con- sequence, and he had to leave the completion of the map to K. Hofmann. Soon after the mathematical development by Clausius and Sir William Thomson of the mechanical theory of heat, Kirchhoff was the first to carry the application of that fruitful theory into the domain of Chemical Physics. The thermal phenomena connected with the absorption of gases and the dissolution of salts in liquids as well as their relationship with the vapour-pressures of the solvent, were treated in two papers of great interest and importance. A few words must be said on Kirchhoft’s papers on elasticity. There are few problems which have occupied so many eminent mathematicians, and our author’s investigations contributed very materially to the progress of that important branch of theoretical physics. Before Kirchhoff’s time Sophia Germain had made an attempt which was only partially successful to establish the equations which regulate the vibrations of thin plates. Poisson had gone a good deal further, especially as regards the treatment of rectangular plates. Kirchhoff points out that Poisson’s boundary conditions cannot in general be satisfied, and deduces from the general theory of elasticity a solution which can be applied to circular plates. With the help of measurements made by M. Strehlke, the theoretical results were checked and verified by experiment. In some later papers the elastic deformations of rods were treated in a more general way than had previously been done, and especially in 1879 the solution of the problem was extended to prismatic and conical rods. The science of hydrodynamics also is indebted to Kirchhoff for several beautiful investigations, amongst which special attention may be drawn to the paper “ Zur Theorie freier Fliissigkeitsstrahlen,” and to one in which it is shown that two rigid rings in a fluid moving irrotationally exert apparent forces on each other which are identical with those which the rings beet show if electric currents were to circulate round them. Kirchhoff’s papers have been collected into a volume of moderate size. He has also published a series of lectures on mechanics, in which we are especially struck with the precision with which the subject is treated, and with the way all metaphysical difficulties in the first definitions are avoided. ‘For this reason,” he says in the introduction, ‘‘I take it to be the object of mechanics to describe the phenomena of nature, to describe them completely and in the simplest manner. I mean that it will be our task to state what the phenomena are, but not to find out the causes.” None of those who have attended Kirchhoft’s lectures on mathematical physics are ever likely to forget them. Each lecture was complete in itself, and the student felt on leaving the room that he had learnt 1X something which it would be difficult or impossible for him to find in the published books. He was in consequence a popular and successful teacher, and nearly all the younger German physicists are his pupils. } In Kirchhoff science has lost a man who combined, to an excep- tional degree, mathematical talent with observational skill and experimental knowledve. KOOSE Dr. Batrour Stewart was born in Edinburgh on November Ist, 1828, and died in Ireland on December 18th, 1887, having just entered his sixtieth year. He was educated for a mercantile profes- sion, and in fact spent some time in Leith, and afterwards in Australia, as a man of business. But the bent of his mind towards physical science was so strong that he resumed his studies in Edin- burgh University, and soon became assistant to Professor J. D. Forbes, of whose class he had been a distinguished member. This association with one of the ablest experimenters of the day seems to have had much influence on his career; for Forbes’s researches (other than his Glacier work) were mainly in the department of Heat, Meteorology, and Terrestrial Magnetism, and it was to these subjects that Stewart devoted the greater part of his life. In the classes of Professor Kelland, Stewart had a brilliant career; and gave evidence that he might have become a mathematician, had he not contined himself almost exclusively to experimental science. In 1858, while he was still with Forbes, Stewart completed the first set of his investigations on Radiant Heat, and arrived at a remarkable extension of Prévost’s ‘‘ Law of Exchanges.” His paper (which was published in the ‘ Transactions of the Royal Society of Kidinburgh’) contained the greatest step which had been taken in the subject since the early days of Melloni and Forbes. The fact that radiation is not a mere surface phenomenon, but takes place like absorption throughout the interior of bodies, was seen to be an imme- diate consequence of the new mode in which Stewart viewed the subject. Stewart’s reasoning is, throughout, of an extremely simple character, and is based entirely upon the assumption (taken as an experimentally ascertained fact) that in an enclosure, impervious to heat and containing no source of heat, not only will the contents acquire the same temperature, but the radiation at all points and in all directions will ultimately become the same, in character and in intensity alike. It follows that the radiation is, throughout, that of a black body at the temperature of the enclosure. From this, by the simplest reasoning, it follows that the radiating and absorbing powers of any substance must be exactly proportional to one another (equal, in fact, if measured in proper units), not merely for the radiation as c 2 x a whole, but for every definitely specified constituent of it. In Stewart’s paper (as in those of the majority of young authors) there was a great deal of redundant matter, intended to show that his new views were compatible with all that had been previously known, and in consequence his work has been somewhat lightly spoken of, even by some competent judges. These allow that he succeeded in showing that equality of radiation and absorption is consistent with all that was known; but they refuse to acknowledge that he had proved it to be necessarily true. To such we would recom- mend a perusal of Stewart’s article in the ‘ Philosophical Magazine’ (vol. 25, 1863, p. 354), where they will find his own views about the meaning of his own paper. The only well-founded objection which has been raised to Stewart’s proof applies equally to all proofs which have since been given, viz., in none of them is provision made for the peculiar phenomena of fluorescence and phosphorescence. The subject of radiation, and connected properties of the lumini- ferous medium, occupied Stewart’s mind at intervals to the very end of his life, and led to a number of observations and experiments, most of which have been laid before the Royal Society. Such are the “ Observations with a Rigid Spectroscope,” and those on the “Heating of a Disk by rapid Rotation in vacuo,” in which the present writer took part. Other allied speculations are on the con- nexion between “ Solar Spots and Planetary Configurations,” and on ‘Thermal Equilibrium in an Enclosure containing Matter in Visible Motion.” From 1859 to 1870 Stewart occupied, with distinguished success, the post of Director of the Kew Observatory. Thence he was transferred to Manchester as Professor of Physics in the Owens College, in which capacity he remained till his death. His main subject for many years was Terrestrial Magnetism; and on it he wrote an excellent article for the recent edition of the ‘ Encyclopedia Britannica.’ A very complete summary of his work on this subject has been given by Schuster in the ‘ Manchester Memoirs’ (4th series, vol. 1, 1888). In the same article will be found a complete list of Stewart’s papers. Among the separate works published by Stewart, his ‘ Treatise on Heat,’ which has already reached its fifth edition, must be specially mentioned. It is an excellent introduction to the subject, though written much more from the experimental than from the theoretical point of view. In the discussion of radiation, however, which is given at considerable length, a great deal of theoretical matter of a highly original character is introduced. Of another work, in which Stewart took a great part, ‘The Unseen Universe,” the writer cannot speak at length. It has X1 ‘passed through many editions, and has experienced every variety of reception—from hearty welcome and approval in some quarters to the extremes of fierce denunciation, or of lofty scorn, in others. What- ever its merits or demerits it has undoubtedly been successful in one of its main objects, viz., in showing how baseless is the common statement that ‘Science is incompatible with Religion.” It calls attention to the simple fact, ignored by too many professed instructors of the public, that human science has its limits; and that there are realities with which it is altogether incompetent to deal. Personally, Stewart was one of the most loveable of men, modest and unassuming, but full of the most weird and grotesque ideas. His conversation could not fail to set one a-thinking, and in that respect he was singularly like Clerk-Maxwell. In 1870 he met with a frightful railway accident, from the effects of which he never fully recovered. He passed in a few months from the vigorous activity of the prime of life to grey-headed old age. But his characteristic patience was unrufiled and his intellect unimpaired. He became a Fellow of the Royal Society in 1862, and in 1868 he received the Rumford Medal. His life was an active and highly useful one; and his work, whether it took the form of original investigation, of accurate and laborious observation, or of practical teaching, was always heartily and conscientiously carried out. When a statement such as this can be truthfully made, it needs no amplification. PGi Dr. Owen ReEzs was born at Smyrna in November, 1813. His father was a Levantine merchant, and married an Italian lady, by whom he had a large family. Owing to his father’s failure in business, he was obliged to be educated at a private school, and for the same reason many of his family in after years were compelled to reside with him. This is probably the explanation of his remaining un- married. He, however, found a good patron in his uncle, who was a partner in the publishing firm of Longman and Co. In 1829 Owen Rees was apprenticed to Mr. Richard Stocker, the apothecary at Guy’s Hospital, and he very soon showed his inclination towards scientific pursuits, and especially to chemistry. He attracted the attention of Dr. Bright, who reauested his assistance in the analysis of the secretions in diseases of the kidney, and in this way a lifelong friendship sprang up between them. He made quantitative analyses of the albumen and urea in the urine, and proved the presence of the latter in the blood. His papers on this subject are to be found in the ‘ Medical Gazette’ for the year 1853. In the year 1837 he took his degree at Glasgow, and shortly after- _ wards published a small work entitled ‘Analysis of the Blood and Xi Urine in Health and Disease.’ In his preface the author says “ the increased desire for more intimate acquaintance with animal chemistry, which has lately been evinced by the medical profession, induces me to present this httle work to public notice. The more philosophical modes of investigation at present adopted to ascertain the diseased conditions of the living system, have found a new branch of inquiry deserving the attention of the student.’’ He then describes his method of separating the various ingredients of the bloed, and as regards his discovery of urea he evaporated the blood to dryness and treated the residue with ether. He also made an exhaustive analysis of the urine, showing that the colouring-matter was a distinct principle, and gave the various tests for albumen. Bright had already observed that the phosphates were precipitated by heat, and thus was some- times a cause of error in testing for albumen. He referred to Rees for an explanation, who, after a series of experiments, determined that it was muriate of ammonia which kept the phosphates in solu- tion, and that 1t was the decomposition of this which thus necessarily caused their precipitation. For the presence of sugar he did not use chemical tests, but evaporated the urine and dissolved out by alcohol. In a paper published in 1838 in the ‘ Guy’s Hospital Reports,’ Rees showed how sugar could be obtained from diabetic blood, as its pre- sence therein had been previously doubted. He evaporated the blood, soaked the residue in water, treated with ether to remove urea and fat, and then allowed the remainder to crystallise. In the year 1841 Rees made, in conjunction with Mr. Samuel Lane, some very important observations on the corpuscle of the blood. They concluded that it was a flattened capsule containing a coloured fluid, and they further showed the changes which it underwent on the application of reagents as saline fluids and syrup. They inferred from this that in the living body there must be a similar osmotic change going on, as in anemia and in cases where the saline sub- stances were in excess. Rees subsequently made observations on the nucleus of the corpuscle in different animals, and showed the simi- larity of the white corpuscle to that of lymph and pus. Although finding urea in various secretions in cases of diseases of the kidney, yet often failing to discover it in the blood, he doubted whether its presence was the cause of convulsions and other nervous symptoms so frequently met with in Morbus Brighti. He communicated two papers to the Royal Society—one in 1842 entitled “ On the Chemical Analysis of the Contents of the Thoracic Duct in the Human Subject.” The fluid was obtained from a criminal executed at Newgate, and taken an hour after death. An article on chyle and milk, written afterwards, is to be found in Todd and Bowman’s ‘ Cyclopedia of Anatomy and Physiology.’ His other paper presented to the Royal Society was entitled ‘‘On the Formation xl ‘of the Red Corpuscles of the Blood and on the Process of Arterialisa- tion.” His theory was that the venous blood contained phosphorus in combination with fat, and that an oxidation took place, and the phos- phoric acid united with the alkali of the blood, producing a tribasic phosphate of soda. This caused the bright colour of arterial blood. Rees also wrote a little book on calculous diseases. This con- sisted mainly of the Croonian Lectures given at the College of Physicians in the year 1856. In the ‘ Guy’s Hospital Reports’ various papers will be found on chemical analysis of animal fluids. Owen Rees, in many instances, joined Dr. Alfred Taylor in his criminal investigations, notably in the case of Palmer, who was tried for the murder of Cook by strychnia in the year 1856. He also assisted Sir B. Brodie in his analysis of urinary calculi, and it was owing to this surgeon’s influence that Dr. Rees gained the appointment of Physician to the new Pentonville Prison. Dr. Owen Rees was appointed Assistant-Physician at Guy’s Hospital im the year 1843, and full Physician in 1856. In 1873 he resigned, and was appointed Consulting Physician. He was a particular friend of Dr. Roget, who presented the papers spoken of to the Royal Society, of which Dr. Roget was then Secretary. It was soon after- wards, in the year 1843, that he was made a Fellow. Dr. Rees was in practice first in Cork Street and afterwards in Albemarle Street. Huis clients were amongst the better classes, and usually sufferers from kidney disease or gout, for the treatment of which disorders he had gained considerable repute. Personally, he was a small, lithe, active man, ready and sociable, so that he was a well-known member at the Atheneum and many convivial clubs. He was very quaint and humorous in his stories, so that his company was much sought after. He was, in his latter days, made Physician Extraordinary to the Queen. In the beginning of 1886 he was seized with a paralytic stroke, but although he partly recovered he never did much work afterwards. On May 27th, 1889, he had another seizure, which proved fatal, and he was buried in Abney Park Cemetery, aged 76 years. S. W . Sir Crarius James Fox Bunsoury, Bart., was born at Messina, in Sicily, February 4th, 1809, where his father, General Sir Henry Bunbury, was at that time Quartermaster-General. His mother was a daughter of General Fox, then commanding in the Mediterranean, and a niece of the celebrated statesman. To these gifted parents Sir Charles owed his early love and his knowledge of arts, literature, and science, and especially of natural history, accomplishments which he cultivated throughout hfe with disinterested zeal; and thanks to his extraordinary memory, his accuracy was as remarkable as were the extent and variety of his information. VOR. SL VI; d Np ob X1V After completing his education at Trinity College, Cambridge, Mr. Bunbury visited Brazil and the River Plate, whither he was attracted by the fact of his uncle, Mr. Fox, himself an ardent collector of plants, being Minister at Monte Video. This was followed by a voyage to South Africa, where another uncle, General Sir George Napier, was Governor of the Cape Colony ; and in 1853 he accompanied Sir Charles Lyell to Madeira and Teneriffe. In all these countries Sir Charles Bunbury made extended excursions, observing diligently and collecting assiduously, though travelling as an amateur rather than a scientific naturalist. The results of these journeys are full of interest to the botanist, zoologist, and geologist ; they are published in various scientific periodicals, and in a ‘ Visit to the Cape,’ which appeared in 1847. Hspecially valuable are the botanical observations made in South Africa and South America, which deal with the broad features of a vegetation known previously only in detail. They are brought together in a volume published shortly before his death, entitled ‘ Botanical Fragments.’ It is, however, by his researches in vegetable paleontology that Sir Charles Bunbury is best known as a scientific man. To this subject his attention was more immediately drawn through his con- nexion by marriage with Sir Charles Lyell, and his most valuable contributions to it may be said to be ancillary to Sir Charles’s inves- tigations into the coal-measures of British North America and the United States; they appeared in the form of a succession of commu- nications to the Geological Society of London between 1846 and 1861, and are printed in that Society’s Journal. He also wrote on the Carboniferous flora of the Tarentaise, on the Anthracites of Savoy, on the Jurassic flora of Yorkshire, on the Fossil plants of Nagpur in the Deccan Peninsula, and of the Island of Madeira. Under this head, too, should be recorded the great services he rendered to paleeon- tology, by classifying and naming the Carboniferous fossils in the Museum of the Geological Society (of which Society he was Foreign Secretary from 1847 to 1853). This collection was for many years the only one of its kind in England available to geologists or botanists. In 1844 Mr. Bunbury married Frances Joanna, daughter of Leonard Horner, Hsq., F.R.S., and sister to Lady Lyell, who survived him. In 1860 he succeeded, through the death of his father, to the baronetage, and removed from the Manor House of Mildenhall, to the family seat, Barton Hall, Bury St. Edmunds, where he died June 18th, 1886, leaving no descendants. He was a Fellow of the Linnean and Geological Societies, as well as of the Royal Society, into which he was elected in 185]. J ald, et XV Asa Gray was born November 8, 1810, in the township of Paris, ‘Oneida Co., New York. He was descended on the father’s side from a Scotch-Irish family that had emigrated early in the 18th century. His mother was a lady of English descent. As a boy he assisted in his father’s farming, and, showing an aptitude for and love of book- work, he was sent, first to a private school, thence to the Grammar School of Clinton, N.Y.,and lastly to the Fairfield Academy. To this latter institution a medical school of repute was attached, and it was through attendance on its lectures that Gray became interested in scientific pursuits, and especially in botany, through an article in ‘'The Edinburgh Encyclopedia.’ In 1825 he entered the Fairfield Medical School, the sessions of which occupying only half the year, left him ample time for following his favourite pursuits of botany and mineralogy in the study and in the fields. In 1831, having taken his doctor’s degree at Fairfield, he forthwith abandoned the thoughts of medicine as a profession, and accepted the post of Instructor in Chemistry, Mineralogy, and Botany in the High School of Utica, N.Y. After spending several years in botanising and in lecturing in various educational establishments, he became Assistant to Professor Torrey in the Chemical Laboratory of the Medical School at New ‘York. This, though it led to nothing professionally, was perhaps the turning point in Gray’s career, for Torrey was an able and ardent botanist, who had already recognised Gray’s ability, and a life-long friendship was established between them, to -be emphasised by the joint publication of ‘The Flora of the North American Continent,’ a work justly esteemed as second alone to De Candolle’s ‘ Prodromus Regni Vegetabilis ’ as a contribution to a knowledge of the vegetation of the globe. In 1835 Gray became Curator and Librarian of the New York Lyceum of Natural History, a post which gave him abundant leisure ; and this he employed in the preparation of his ‘Hlements of Botany,’ which was at once accepted as the best text-book of the science that had appeared in the States, and as second to none in the English language. The ‘Hlements’ is the first of a series of educational works on morphoiogical, physiological, and systematic botany that have been for half a century the class-books of schools and colleges throughout the United States and in British America, and which have been cordially recommended by teachers in England as the best of their class. Nor should mention be omitted of two smaller educa- tional works, entitled ‘ How Plants Grow,’ and ‘ How Plants Behave,’ which, ‘‘ for the interest of their subject, the elegance of their diction, and the lucidity of their style, have led the general public to appre- ciate the scientific aspect of botany more perhaps than have any other in the Enylish language.’’* * Of these libelli a competent American author has written that “they found XV1 In 1836 Dr. Gray was appointed Botanist to Commodore Wilkes’s voyage of exploration in the Pacific and Antarctic regions; but after experiencing innumerable delays, and uncertainties as to the manage- ment of the expedition, and as to his own position in it, he withdrew from the enterprise. It is idle to speculate on the loss to science thus incurred. It may reasonably be assumed, however, that if science lost much in the form of invaluable observations, original researches, and copious collections, America gained much by the retention of Gray’s personal influence, his teaching, and the elaboration of its flora. Settling in New York, Gray now devoted his whole energies in conjunction with Torrey to ‘ The Flora of North America,’ of which the first parts appeared in 1838, and the last that have been published very shortly before his decease. Torrey was the projector of the work, but even from the first the lion’s share fell to Gray, who is prac- tically its sole author. To put briefly the amount of labour involved in Gray’s systematic and descriptive publications on the North Amerivan Flora,it may ke stated that they may embrace in one form or another a great proportion of the 10,000 or 11,000 species that the continent possesses. Of these more than half are so carefully and methodically described in the volumes of the Flora that have appeared, that there is perhaps no instance of a species being misplaced as to genus, and in few could a better grouping of species into subordinate divisions be suggested. The remainder are described in more or less detail in innumerable papers, in answer to demands for immediate publication in the ‘ Reports of Government Expeditions,’ or in the works of travellers and collectors. These scattered publications would, as it was hoped by the author, have accelerated the pace of the great work; but the contrary was the result, and the prospects of the com- pletion of the Flora are far distant, if existent. Of Gray’s numerous gther works four are especiaily noteworthy : his ‘ Manual of the Botany of the Northern United States,’ of which it is justly written by an eminent American author, that the botanist has yet to be born who could give a more clear, accurate, and com- pact account of the flora of a country; the ‘Genera Flore Americe Borealis Orientalis illustrata,’ a work designed to illustrate and describe the morphology, affinities, and distribution of plants in the area indicated, but discontinued after the first two volumes; the ‘Botany of Commodore Wilkes’s South Pacific Exploring Expedi- tion,’ of which a quarto volume, with a superb atlas of plates, was published, when the withdrawal of funds arrested its further pro- gress; lastly, an essay on the flora of Japan, which, in point of their way where botany as botany could not have gained an entrance, and they set in motion a current which moved in the general direction of a Elie science with a force that can hardly be estimated.” XV1l originality and far-reaching results, is the author’s opus magnum. In it, by a comparison of the floras of Hastern and Western America with one another and with Japan, and of all with the Tertiary flora of North America, Gray has outlined the history of the vegetation of the north temperate zone in relation to its past and present geogra- phical features, from the Cretaceous period to the present time. The above are works of research, but there remain two labours of this most industrious botanist which demand a notice; these are the part he took in the controversy that followed the publication of Darwin’s ‘ Origin of Species,’ and his extraordinary activity as a reviewer, biblio- grapher, and historian of the progress of botany during his life-time. Gray was one of the first to accept and defend the doctrine of natural selection, which he further fortified by masterly reasoning, judicious criticism, and by experiments ; so that Darwin, whilst fully recognising the different standpoints from which he and Gray took their departures, and their divergence of opinion on important poiuts, nevertheless regarded him as the naturalist who had most thoroughly gauged the ‘ Origin of Species,’ and as a tower of strength to himself and his cause. It is not needful to dwell further on this subject ; Gray’s intimacy with Darwin, and their most interesting and instruc- tive correspondence, are matters of history, and together with their divergent sentiments, are fully set forth in the life of the latter, and in two works by Gray entitled ‘ Darwiniana’ and ‘Science and Re- ligion.’ It remains to allude to Gray’s labours as a reviewer and biblio- grapher. Amongst his many accomplishments, not the least was his intimate knowledge of the early and latter history of botany, and of the writings and doings of botanists everywhere. For fifty years (the last thirty as co-editor of ‘Silliman’s Journal’) he kept the American scientific public fully informed of the progress of his favourite science in Hurope and elsewhere, of all publications of value, of the move- ments of botanical travellers, and of the changes in the staff of museums, gardens, herbaria, &c. An American* colleague says of him, ‘‘ As a reviewer he was certainly extraordinary. Some of his reviews were, 1n reality, elaborate essays, in which, taking the work of another as a text, he presented his own views on important points in a masterly manner. Others were technically critical, while some ‘were concise and clear summaries of lengthy works. Taken collec- tively, they show better than any other of his writings the literary excellence of his style, as well as his great fertility and acuteness as a critic. Never unfair, never ill natured, his sharp criticism, like the surgeon’s knife, aimed not to wound, but to cure; and if he sometimes felt it his duty to be severe, he never failed to praise what was * Professor Farlow, ‘‘ Memorialof Asa Gray,” in the ‘ Proceedings of the American Academy of Arts and Sciences,’ p. 33. XVI worthy. His style was so easy, so flowing, and so constantly en- livened by sprightly allusions and pleasing metaphors, that one can read what he wrote for the mere pleasure of reading it. He was one of the rare cases where science had appropriated to herself one who who would have been an ornament to any purely literary profession.” In 1842 Gray was appointed to fill the newly-endowed chair (the Fisher) of Natural History in Harvard College, to which was attached the direction of the Botanical Gardens at Cambridge, Mass. From this time he devoted his chief energies to creating a botanical library and herbarium, and to the continuation of the Flora of North America. . For upwards of thirty years he fulfilled the duties of Lecturer and of Director of the Gardens, during which he raised the whole botanical establishment, garden, library, and herbarium, to first-rate importance. In 1872 he was relieved of the duties of lecturing, and shortly after of the charge of the garden, and had an assistant appointed to the herbarium ; but he retained the title of Fisher Professor and Director of the Gardens until his death. _ Having made six visits to Europe, entailing several lengthy stays in England, in furtherance of the Flora, his wiry figure, his vivacity, and the alertness of his intellect were well known in this country, where his highly cultivated mind and the charm of his personality won him friends in all circles of society. His last visit was in 1887, — soon after his return from which he was struck with paralysis, and died on the 30th of the following January, on his seventy-eighth birthday. | Dr. Gray married, in 1858, Jane, daughter of C. G. Loring, of Boston, aud had no family. He was a correspondent of the Institute of France, a Doctor of Laws of Oxford and Edinburgh, and a Doctor of Science of Cambridge. He was elected foreign member of the Linnean Society in 1850, and of the Royal Society in 1873. He was a fellow or correspondent of the principal Continental scientitic academies, and had served as President and for sixteen years as Cor- responding Secretary of the American Academy of Arts and Sciences, and of the American Association for the Advancement of Science, and he was a Regent of the Smithsonian Institution. He is credited down to the year 1873 with no fewer than 107 papers in this Society’s Catalogue of Scientific Papers, and with upwards of 350 scientific works and papers in a chronologically arranged catalogue of these, appended to the 36th volume of the ‘ American Journal of Arts and Sciences’ (September, 1888). : J. DAE Sik WinitAM O’SHavucHnessy Brooke, F.R.S., died on the 8th of January, 1889, at Southsea, after a short illness. He was born in Limerick in 1809, and was therefore in his 80th year. His original xX1xX name was William O’Shaughnessy, but he took the name of Brooke on the death of a relative of that name. He graduated as M.D. at Edinburgh in 1833, and shortly afterwards joined the Bengal Army as Assistant Surgeon. He was promoted to Surgeon in 1848, and to Surgeon-Major in 1858. . In 1835 he was appointed Professor of Chemistry in the Medical College at Calcutta. From 1844 to 1851 he acted as Assay Master of the Calcutta Mint. He was of a scientific turn of mind, and took readily to the experiments made by Cooke and Wheatstone in telegraphy in 1837. He made some exper'- ments in submarine telegraphy across the Hooghly, at Calcutta, in 1839, and he was the first to introduce the telegraph into India. In 1852 he was appointed Superintendent-General of Telegraphs in India, and he retained that post until 1862, when he resigned and retired from the Indian Medical Service. He was the author of several papers on scientific and engineering subjects, many of which appeared in the Journals of the Asiatic Society. He was knighted for his valuable services in establishing the service of telegraphs throughout India, and he was elected a Fellow of the Royal Society in 1845. W..( EL. PB, Watter Wetpon, F.R.S.; born 3lst October, 1832; died 20th September, 1885. Very little is known of the early history of the subject of this memoir, beyond the bare facts that he was born at Loughborough on the 31st October, 1832; that he was the eldest son of a manufacturer in that town, and was employed for some years in his father’s business; that while so occupied he discovered a taste for literature; and that, in his twenty-second year, he left his native town, and arrived in London determined to make his way as a journalist. With him he brought his young wife, whom he had just married, and who was destined to be his never failing source of conso- lation and encouragement during those early years of difficulty and adversity which are invariably experienced by a young man beginning an independent life under such circumstances. Young Weldon most certainly had his full share of dark days; and in speaking of them in after life to those who knew him well, he loved to dwell on the sus- tainment and encouragement he had derived from his devoted wife. Apart from this, however, he was endowed by Nature with a variety of gifts, any one of which might have enabled him to acquit himself well in the battle of life, the combination of which was irre- sistible, and served not only to raise him toa position of distinction and honour, but to render him capable of performing work which has undoubtedly been, and will probably long continue to be, a benefit to eivilised humanity. : Mr. Weldon’s first journalistic work was done in connexion with e Xx ‘The Dial,’ afterwards incorporated with ‘The Morning Star,’ now dead, but in its time a Liberal daily paper of some importance. While thus engaged, he conceived the idea of issuing, at a price which should bring it within the reach of all, a monthly journal devoted to recording current progress in. literature and science— subjects which were ever twin sisters in his mind. The connexions he had as a journalist made among writers and scientists on the one hand, and country booksellers on the other, put the production and issue of such a.work within his power; and that there was likely to be a demand for such information as he sought to give he felt con-’ vinced from his own youthful needs and experiences. His purpose was that the periodical should be issued in London under his own name, and simultaneously in various provincial towns, in each case as the journal of any local bookseller who should subscribe for a certain number of copies. Accordingly, the first number of ‘ Weldon’s Register of Facts and Occurrences in Literature, Science, and Art * was published in London on the Ist August, 1860, at the price— moderate, even when compared with the cost of such periodicals at the present time—of 6d. Its proprietor spared no effort to render the work valuable and attractive to those who sought its pages, and secured for it contributions from many men then or since dis- tinguished in science, letters, or art. But those were not the days of an earnest popular desire for such information as ‘ Weldon’s Register’ sought to impart, and, without such a demand, at so low a’ price, it had no chance of success. Consequently, after an existence of some three years, it was abandoned by its projector, who now turned his attention to another and strangely different object. tal The practical failure of an ardentiy cherished scheme, the abandon- ment of work for which he rightly considered himself specially fitted, was no doubt a severe blow. But Mr. Weldon knew not failure in the ordinary sense. To come short of success in one way was, with him, but an incentive to seek it with redoubled vigour in another. No one could know him well and observe him closely without recog- nising not only the great scope of his talents, but also the marvellous avidity and thoroughness with which he grasped any subject upon which he brought his mind to bear. In him, moreover, a strong and active mind was allied with constitutional power and a capacity and’ love for work which it is the good fortune of but few to possess. This is the simple and only explanation of the astonishing fact that, without any education in science, without any technical training, without the advantage to be gained by attending lectures or watching the performance of experiments—with nothing to help him through but his genius and the knowledge he could acquire by sheer hard’ reading at the British Museum—Mr. Weldon now attacked the problems and difficulties of industrial chemistry. Why he turned XX1- his attention to a task so different from all his previous occupations cannot be stated with certainty. In an admirable memoir of him, published in the ‘Journal of the Society of Chemical Industry’ in October, 1885, it has been suggested that he derived his first impulse to this new work from his friend the late Charles Townsend Hook, the well-known paper maker of Snodland; and the writer has good reason to believe that the suggestion is well grounded. From whatever cause, Mr. Weldon, from that time to the very hour of his death, devoted himself, with all the earnestness, zeal, and energy of which he was capable, to the study of industrial chemistry, and of the chlorine and alkali manufactures in particular. He thoroughly mastered his subject in all its details, whether from a scientific or a business point of view, insomuch that during the last ten years of his life he was regarded as the highest authority upon it, not only in England, but wherever the manufacture of alkali was carried on. It may safely be averred that, so long as the practice or the memory of this industry shall last, so long will the name of Walter Weldon be honourably associated with it. The great work of his life, his process for the perpetual regenera- tion of the manganese oxide used in the production of chlorine from the hydrochloric acid which is the by-product of the Leblanc soda process has been so often described, and is so widely known, as to need no detailed explanation here. No better description of it exists than that, written by the hand of the inventor, published in the ‘Journal of the Society of Chemical Industry,’ Sept., 1885 (vol. 4, p- 525). Suffice it to say that it produced a revolution in the industry which it affected, supplanting a method of working at once crude, wasteful, and noxious; that it has saved an expenditure to this country of about £750,000 per annum since it has been in opera- tion; and that it has been one of the chief factors in bringing the purchase of bleached fabrics—linen, calico, paper, &c.—well within the power of the poorest classes. To invent a good and workable chemical process, however, is not sufficient ; and it was perhaps as an exploitant and as a man of business (though without a trace of the sordid attributes of the mere business man), in the power of fixing the interest, influencing the minds, and attracting the sympathies of those with whom he had to deal, that Mr. Weldon specially excelled. But for these powers, it is doubtful whether his process—so advan- tageous in its use, and so facile in its working—would ever have been put into practical execution. With all these advantages, it required many years of arduous and anxious work—not to mention the taking of many patents—before Weldon’s process became, what it still is, the almost universally adopted method of producing chlorine. Patented in 1866, and temporarily experimented with soon after- e 2 XXli wards at the works of the Walker Alkali Company, on the Tyne, it was not until late in 1868 that Weldon’s regenerated-manganese chlorine process Was in operation on a manufacturing scale, at the works of Messrs. J. C. Gamble and Sons, at St. Helens. By the end of 1870, however, out of about forty chlorine makers in the United Kingdom, thirty-five had taken licences for its use, seventeen plants being then either actually at work or on the point of completion. But a formidable rival now arose, in the shape of Mr. Deacon’s process for producing chlorine by passing hydrochloric acid gas over masses of pumice stone heated to a certain temperature and satu- rated with cupric sulphate. Questions of cost apart, the chief merits of this process were (1) its great simplicity; (2) that, per unit of NaCl, it yielded a larger proportion of chlorine than did the Weldon lime process. To meet it, Mr. Weldon again attempted to work the process which he had patented contemporaneously with his lime pro- cess, for treating manganese chloride residues by magnesia, so as to recover in the form of hydrochloric acid the proportion of chlorine otherwise lost as calcium chloride. But the Weldon lime process withstood the attacks of all competitors, and by the end of 1875 it had been adopted by every chlorine manufacturer of importance throughout Europe. From the time of the introduction of his chlorine process‘until the end of 1881, when the patents for it were about to expire, and when his active and pecuniary interest in it ceased perforce, Mr. Weldon was constantly occupied in travel and work connected with the setting up of instailations in all parts of the United Kingdom and the Continent, and in devising minor improve- ments in working. The spring of 1882 brought him relief from this kind of work, but no leisure. Moreover, he had recently suffered the severest bereavement that can befall a man: the sudden death of his younger son, Dante, had been followed only a few weeks later by that of one of the best wives that ever graced an English home. He now, too, began to feel severely the effects of that overwork and un- sparing exposure of himself in the cause of duty which had been going on for fourteen years, sapping a constitution once of the most robust. Many men in his position, under the combined influences of success and sorrow, would now have been content to retire more or less from the active work of life: not so Mr. Weldon. Indeed some of the most useful, and possibly the greatest, work of his life was yet to be accomplished. During 1881 he had been conspicuous as one of the founders of the Society of Chemical Industry—a Society already the most useful, the most successful, and, with one exception, the largest of its kind. To the development and successful working of this Society he devoted an infinite amount of loving labour and thought, whether as member of its Council, as Chairman of its London section, XXIll or as President, which last position he filled from July, 1883, to July, 1884. To the meetings of this Society he contributed many im- portant papers, all bearing on the industry which he had made his special study, and some of them—notably that “‘ On the Present Position of the Soda Industry” (8th January, 1883) ; his Presidential Address (9th July, 1884); and that on ‘‘The Proposal to Raise a Memorial tu Nicolas Leblanc” (5th March, 1885)—of such literary as well as intrinsic merit as to create a deep and lasting impression on those who heard or read them. It may truly be said of Mr. Weldon that he was always working and always learning. Every hour spent in travel, every hour that could be snatched from actual pen-work (for, until the last three years of his life, he did nearly the whole of the vast correspondence incidental to his position with his own hand, often spending some ten hours a day in sheer writing) was devoted to the planning or studying out of new chemical processes or improvements on old methods. From the earliest years of his chemical work, as has been shown above, he had cherished and laboured at the idea of a cheap and practicable magnesia-chlorine process; and he was now to have the satisfaction of arriving at a solution of the problem from a chemical point of view, and also of seeing the mechanical difficulties of such a method ina fair way to be mastered by the engineering skill of his close friend and collaboratewr, Monsieur Pechiney. This new chlorine process—which its inventor confidently expected to produce as great a revolution in the alkali trade as had resulted from the adoption of his lime-manganese process twenty years ago—was fully described by Mr. Weldon in his memorable address to the Society of Chemical Industry, at Newcastle, on the completion of his Presidential year, in July, 1884; and again in the Journal of that Society for September, 1885. It may be briefly described as follows: Solution of chloride of magnesium— obtained either by the neutra- lization of hydrochloric acid by magnesia, or by decomposing the residual ammonium chloride of the ammonia-soda process by mag- nesia; or as the Stassfurt native salt—is evaporated down to a certain point. Sufficient magnesia is then added to produce a solid mass containing about six equivalents of water. This mass is further dried and is then crushed into morsels of about the size of a walnut, which morsels are subjected to a current of air in a special furnace, invented by M. Pechiney, the result being that nearly the whole of the chlorine present is evolved, partly in the free state and partly as hydrochloric acid. The process has been in regular opera- tion at the works of Messrs. A. R. Pechiney et Cie., Salindres, since July, 1887, with highly satisfactory results. Mr. Weldon was well known as a regular attendant at the meetings _of the British Association, and as a frequent contributor of papers to es srl EN eB Ss “ SS SS XXIV Section B. Indeed, the last labour of his life, his work ‘On the Ratios One to Another of the Atomic Weights of the Elements,’ Chapter I of which, “ The Glucinum Family,” was printed only a few days before the Aberdeen Meeting of 1885—was done with a special view to its consideration by the members of the Association. At what cost he went to Aberdeen, in September, 1885, none but the few friends who saw him there can realize. But he had never missed one of the meetings of the British Association since he first attended with Mrs. Weldon in 1865, and nothing could shake his resolve to go. So, though over- whelmed with work and full of bodily pain, he hurried from Germany, and, disregarding the remonstrances of his friends, went straight on to Aberdeen; but only to break down completely on arriving there. After remaining for eight days a prisoner in his hotel, he determined to return alone to his home in Surrey. There he arrived on the 16th September, in such a condition as to inspire the gravest alarm in his friends. Much too late, he now sought that relief in complete rest which he had been entreated to take for years past, doing nothing more during the next three days than dictate a few short letters to old personal friends. In one of them he said: “All work of all kinds is forbidden me—a prohibition which, of course, I shall not be able to obey. But the change which I have so long dreaded is certainly come at last. I had trusted to beable to keep in harness to the very last; but they tell me that a day’s work such as I have been accustomed to all my life would be simply suicide, and that of course is not permitted.” Late on the afternoon of the 19th, the writer left him in the full belief that he was really better; but the presaged change had indeed come ; for at 9 o’clock the next morning he was summoned back to that bedside, only to find that the spirit had already passed away. For his many and valuable services to chemical industry, Mr. Weldon received the following distinctions: In France, the Great Medal of La Société d’Encouragement, and the Chevaliership of the Legion of Honour. In this country, he was elected a Fellow of the Royal Society (in 1882), Vice-President of the Chemical Society, Vice- President of the Institute of Chemistry, and President of the Society of Chemical Industry. EW oa Tae late Sir Junius von Haast was born at Bonn, in Germany, on the Ist May, 1824, his father being a wealthy merchant of that city. After passing through the grammar schools of Bonn and Cologne, the subject of our memoir entered the University of Bonn, and devoted a considerable portion of his time to geological and minera- logical studies. After leaving the University, he spent some years XXV in France. He afterwards made extensive journeys over many parts of Europe, visiting Russia, Austria, and Italy. A large firm of shipowners, who wished to direct the stream of emigration from Germany to New Zealand, made him an offer to visit that colony on their behalf, for the purpose of ascertaining its fitness as a field for emigration, an offer which Mr. Haast accepted. Arriving at Auckland in December, see he met Dr. Ferdinand Hochstetter, of the Austrian ‘‘ Novara”? Exploring Expedition, who had just undertaken a geological examination of the North Island on behalf of the Colonial Government. The financial state of the colony at that time, and the disturbances with the Maoris, at once convinced Mr. Haast that it was hardly a suitable field for his countrymen. He accordingly terminated his agreement and joined Dr. Hochstetter’s expedition through the North Island. He was subsequently em- ployed by the Provincial Government of Nelson to explore the western and southern portions of that province. With only four companions, he started on an expedition which took him away from civilised life for a period of eight months. During this journey, in addition to the discovery of the Grey and Buller coal fields, and of several gold-bearing districts, he filled in the topography of a large part of Nelson, and added largely to the knowledge of the geology, as well as the fauna and flora, of these alpine portions of New Zealand. On his return, the Government published a full report of the journey, -and of the scientific and other discoveries which had been made. This report attracted some attention in Hurope, and the Royal University of Tubingen, in 1862, bestowed upon the author the honorary degree of Doctor of Philosophy. The undoubted suceess of this Nelson enterprise induced the Canterbury Government to offer Dr. Haast the position of Provincial Geologist. Accepting the offer, he commenced work by similarly investigating the topography and mineral resources of the western ranges of that province. After several years of continuous labour this work was carried to a successful issue, and the practical results were embodied in a voluminous Report on the Geology of the Pro- vinces of Canterbury and Westland. Years before the publication of _ this complete report the detached accounts of Dr. Haast’s explorations were very favourably received and commented on. Sir R. Murchi- son, the President of the Royal Geographical Society, thus referred to them :—‘‘He was proud to preside upon an occasion when a geutleman, who was a geologist by profession, had proved himself to be a good geographer, and had shown how intimately the subjects of physical geography and geology were united. Dr. Haast’s labours were worthy of all commendation.” To the general reader the book is a highly interesting and instructive one. The very large amount of geological detail, and the breadth and completeness of the author’s XXV1 generalisation as to the stratification and the mode of formation of the Southern Alps, their subsequent carving and denudation by ice and water, the evidence of a glacial epoch similar to that which pro- duced the striz and boulders of Hurope, as well as the account given by him of the nature of Canterbury’s rivers and the formation of its plains, all testify to the industry and acute observation of this learned savant. He was elected a Fellow of the Royal Society in 1867. Some fifty academies and learned societies in various parts of the world enrolled him as a member. The Emperor of Austria con- ferred upon him a patent of hereditary nobility ; and, besides receiv- ing several foreign orders, he was created a C.M.G. by Her Majesty. In 1876 he was appointed Professor of Geology to the Canterbury College, New Zealand University; and in 1850 he was elected a member of the Senate. During his explorations as Provincial Geologist, he commenced the formation of the Canterbury Museum, which, although of such recent growth, has now attained such pro- portions as to be classified by competent authorities as about the thirteenth in rank of the museums of the world, whilst it undoubtedly is the finest in the southern hemisphere. In 1886, Dr. von Haast came to England as one of the Commissioners for the colony at the Colonial and Indian Exhibition; and for his services on that occasion was promoted by Her Majesty to the rank of K.C.M.G. In 1887 he returned to New Zealand, with his wife and daughter, and died somewhat suddenly of heart disease soon after his arrival at his Canterbury home. . Wns The task of writing an obituary notice of the late Dr. C. J. B. WILLIAMS is rendered comparatively easy by the fact that about four years before his death this venerable physician published full memoirs of his life and work, which have saved much trouble and time in ascertaining the various incidents of his career. Dr. Williams, born in 1805, was descended from Welsh parents; his father was the Rev. David Williams, Perpetual Curate of the Collegiate Church of Heytesbury, in Wiltshire, and his mother was the daughter of a surgeon, Mr. Williams, who lived at Chepstow. This lady received some instruction from the late Mrs. Hannah More, who, strictly religious as she was, often took her pupils to witness the acting of Garrick, which she considered an important aid in education. His father, engaged at one period of his life in tuition, especially in the preparation of students for the Universities, when he ceased to receive pupils still conducted the education of his sons; but, ‘although Dr. Williams’ brothers were afterwards sent to public schools, he himself completed his education at home under his father’s super- intendence until he entered the University of Edinburgh. Dr. XXViI Williams seems to have made fair progress in classical learning, but never advanced far in this direction, his mind being interested more in the natural sciences; in after years he came to the conclusion that having had the power of directing his mind for some years to the subjects he liked most was in his case productive of much good, and enabled him to develop his power of originality, which might probably have remained for ever latent had he undergone a rigid course of training in any public school during that period of his life. The writer thinks that frequently this has proved true, and that many of our most original discoverers and advancers of knowledge would have failed to attain great eminence had they been obliged for some of the best years of their lives to pursue studies uncongenial to their tastes. During his stay at home there is one incident in connection with his amusements which may have had some influence over his future acoustic studies ; he says he was very fond of birds and animals; he had his pets and used to spend a good deal of time in the poultry yard, and made a special study of the language of cocks, hens, and chickens, ducks and drakes, turkeys and geese, and in short of all domestic animals, and having a nice ear and considerable power of mimicry, he learnt their various notes, and was able to imitate them well enough to influence the creatures towards him as if he had been one of themselves; he remarks that ‘“‘the brute utterances have all their meanings, and are expressive of various feelings, whether pain or pleasure, anger or love, fear or confidence, defiance or submission, and are mutually intelligible among different animals as words are among human beings.” In the autumn of 1820, Dr. Williams went to Edinburgh as a student of medicine, studied chemistry under Dr. Hope with much pleasure, and anatomy under Professor Monro (¢ertiws) and Dr. Barclay with much less satisfaction; he remarks that at that time the teaching of anatomy was very different from what it is at present, from the absence of plates and manuals; there also he studied botany during the summer, and medical jurisprudence under the late Sir R. Christison. At the same time he commenced his attendance at clinical lectures and hospital practice, and became a pupil and great admirer of Dr. Alison, the Professor of the Institutes of Medicine. In the autumnal vacation, Dr. Williams returned home, the only holiday he had during the period of his medical studies, and in this vacation he was not without amusing resources. He was occasionally gratified by a visit to the theatre, and at different times witnessed the performances of Edmund Kean, Charles Young, Macready, Charles Kemble, the elder Matthews, and of Mrs. Henry Siddons, Miss Stephens, and Miss Paton. Before leaving Hdinburgh, Dr. Williams read a paper at the Royal XXVUl Medical Society (1823), afterwards published as a separate thesis, entitled ‘‘On the Blood and its Changes by Respiration and Secretion,” embodying the views of Lagrange modified by further research, in the three following propositions :— 1. The difference in composition between arterial and venous blood consists chiefly in this, that the former contains an additional quantity of oxygen, and the latter of carbonic acid, chemically united with it ; the affinity between the blood and the oxygen being more powerful than between the blood and carbonic acid. 2. The oxygen gas of the respired air, pervading the walls of the pulmonary vessels, displaces by virtue of its superior affinity an equal bulk of carbonic acid gas, and thus converts venous into arterial blood. 3. In the course of the circulation, the oxygen thus absorbed gradually attracts carbon from the proximate principles of the blood, and uniting with it produces heat, and by thus also forming carbonic acid converts the blood from arterial into venous. The second part of the essay is devoted to the subject of animal heat, and Sir Benjamin Brodie’s experiments are referred to and ~ commented upon. | Bail The author thinks that in this essay, written in 1823, he may be ai allowed to have anticipated by many years some of the views of HI Dumas and Liebig with regard to the changes in the blood through respiration. Soon after taking the degree of M.D. at Edinburgh, Dr. Williams Hi went to Paris, and there became acquainted with the physiologist ‘| Majendie, and saw many very eminent men of science, as La Place, aii Vauquelin, Ampére, Humboldt, Cuvier, Arago, Gay-Lussac, &c., and ii at the commencement of the Medical Session determined to make the Hospital of La Charité and the Clinique of Laennec the chief ah field of his work. An interesting description is given of Laennec, his lll slim frame, his weakness, coupled, however, with quickness of per- ception and intelligence, which enabled him to discover a new system and art for the elucidation of disease. Dr. Williams remarks that i. his teaching was little valued by the French students, and that his + | class chiefly consisted of foreigners and but a sprinkling of his own countrymen, these latter being more attracted by the impetuous Broussais, who captivated them by his grand ideas and sweeping hypotheses without troubling them with dry details or the results of careful observations. Dr. Williams also speaks most warmly of the | knowledge of pathological anatomy which he obtained from Audral, Wy and remarks that in eight months he learnt more of the subject than ii he could have done in eight years in the hospitals of his own country. ih Chomel and Louis were also his instructors, and there can be no doubt that his studies in Paris at this time had a great influence on XX1X his future career, his mind being well fitted to make the best use of all the opportunities he then possessed. Dr. Williams, speaking of Laennec, remarks that ‘‘ the chief discoveries of auscultation and its large development were un- doubtedly his, and have placed him in the foremost rank among the benefactors of mankind.” To these, as well as to his personal teaching, says Dr. Williams, ‘I owe not only’ some of the most valuable knowledge that I have ever acquired, but also the opening up of new avenues of knowledge which will be inexhaustible to the end of time. It was the uew idea of bringing another sense—the sense of hearing—to aid us in the investigation of the organs in health and disease, and through studying its indications, learning as it were language which would tell us of their changes of condition or motion, that gave vastness to the discoveries of Laennec, and would render them fruitful far beyond his own share in them.” After his return from Paris, Dr. Williams went first to Madeira with a patient, and subsequently for a few months to Switzerland with Lord and Lady Minto, as travelling physician. After his return from this last journey, Dr. Williams’ career as a London physician may be said to have commenced. He took a house in Half Moon Street, Piccadilly, and devoted much time to preparing a work on Auscultation, chiefly of the lungs, and wrote several articles in the ‘Cyclopedia of Practical Medicine,’ and afterwards in the ‘ Library of Medicine;’ in the latter work, most of the articles relating to diseases of the respiratory organs were com- mitted to his charge. In his work on ‘ Auscultation,’ his object was to bring in the laws of acoustics in order to explain the various marked phenomena, such as the fine crepitation in pneumonia and metallic tinkling signs which had been discovered, but in no way explained, by Laennec. In his article, “ Coryza,” in the ‘ Cyclopeedia of Medicine,’ the so-called dry method of cure was proposed. Dr. Williams made some observations on slow combustion in 1823, and subsequently gave an evening lecture at the Royal Institution, and a paper was read at the Royal Society; Dr, Williams had always an idea, even when he wrote his Memoirs, that the subject had been shelved by scientific men: he thought it might have an important bearing on spontaneous combustion occurring in coal stores, hay-ricks, &c. The existence of slow forms of combustion, however, is quite recognised and appreciated by chemists and physicists, and the slow combustion of phosphorus must have been known since the discovery of that element. In 1830 Dr. Williams married a maternal cousin, Miss Jenkins, and from 1828 to 1835 he was engaged in the investigation of the causes of the sounds of the heart, an investigation which was originated in conjunction with Dr. Hope, but unfortunately some xk differences arose between him and his fellow- worker, a misunderstand- ing which afterwards became the source of much discomfort. | In 1835 Dr. Williams was elected a Fellow of the Royal Society, but, as will be shown later on, he disapproved of the existing constitu- tion of that Society, preferring a more popular basis of membership, such as was to be found in the then young British Association. On the resignation by Dr. Chambers of the Physicianship of St. George’s Hospital, Dr. Williams offered himself as a candidate for that appointment, in opposition to Dr. Hope, but he soon retired from the candidature, finding that his chances would hardly justify a con- tinuance of the contest. In 1839 the Chair of Medicine at University College, with the Physicianship to the Hospital, became vacant by the retirement of Dr, Elhotson, and Dr. Williams secured the post for himself, and had thus an opportunity made for him where he might utilise his acquire- ments; he gave the Introductory Address at the opening of the Session, which was well received, as the writer of the present notice can testify, he having been one of the audience. At University College and Hospital his colleagues were Drs. Sharpey, Anthony Todd Thomson, D. P. Davies, Dr. (afterwards Sir Robert) Carswell, Messrs. Liston, Samuel Cooper, and Richard Quain. In 1840 Dr. Williams was nominated to the Fellowship of the Royal College of Physicians; he became a Fellow, but says he had some doubt as to accepting the honour, being opposed to the method of election of Fellows and to the constitution of the College altogether, and although great alterations were afterwards made by the passing of the Medical Act of 1858, still he always was more or less antago- nistic to that body: a fact to which subsequent allusion will be made. About this time Dr. Williams’ attention was drawn to the prepara- tion of his ‘ Principles of Medicine,’ which appeared in 1843 and met with a hearty reception by the Profession. In 1846 the Pathological Society was founded, and Dr. Williams was made the first President. Dr. Williams soon became more and more engaged in private prac- tice, and in 1848 resigned his appointment at University College and Hospital and removed to Upper Brook Street, where he remained till the end of his medical career, having been previously ten years in Half Moon Street and eleven years in Holles Street. In the ‘ London Journal of Medicine,’ 1849 (a publication which only existed a very few years), Dr. Williams published a paper on the “ Value of Cod-liver Oil in the Treatment of Pulmonary Consumption,” and the conclusion arrived at was thus summarised :— ‘‘T prescribed the oil in above 400 cases of tuberculous disease eS . the lungs in different stages, and of 243 of these have notes. Out of XXXI this number the oil disagreed and was discontinued in only nine instances. In nineteen cases it appeared to do no good, while in the large proportion of 206 out of 234 its use was followed by marked and unequivocal improvement, varying in degree in different cases from a temporary retardation of the progress of the disease and mitigation of distressing symptoms up to a more or less gon ie restoration to apparent health.” Dr. Williams was by no means the first physician to prescribe cod- liver oil; Dr. Bardsley, of Manchester, had used it for many years, and Dr. Darling and Dr. Hughes Bennett had also anticipated him in the use of this most valuable therapeutic agent. In 1852 Dr. Williams was telegraphed for to Walmer to see the great Duke of Wellington, but he arrived too late; nevertheless, he attended the State Funeral as a medical attendant of the Duke. In 1858 Dr. Williams was elected President of the New Sydenham Society, which was established for the purpose of translating foreign works on medical subjects and the re-publication of important scattered papers. In 1862 Dr. Williams delivered the Lumleian Lectures at the Royal College of Physicians, having previously been Gulstonian Lecturer in 1841. We pass over the remaining years of Dr. Williams’ career as a physician, as the increasing calls of a large practice left him little time for other work of more general interest, only briefly referring to his action for libel against the late Duke and Duchess of Somerset, which ended by his receiving an ample apology, completely clearing his professional character from the aspersions cast upon it in a period of excitement and distress at the loss of her son by the Duchess ; and to the publication in 1871 of a work on Pulmonary Consumpticn, in conjunction with his son, Dr. C. Theodore Williams; and, lastly, his election as President of the Medical aud Chirurgical Society, in 1873, and his appointment as Physician Extraordinary to the Queen, in 1874. In the next year he retired from practice, and made his home at Cannes for the remainder of his life, dying there of pneumonia on March 24th, 1889. After his retirement, among other occupations of a naturally active mind, he spent some time in examining Sun-spots, especially in relation to weather changes, and made many summer visits to England. This brief account of the life of Dr. Charles J. B. Williams would be very incomplete without the addition of some comments on the man and his work, suggested by the perusal of the Memoirs of his Life. One cannot help seeing that he was a man of unusual ability and of great confidence as to his powers—that he was indus- trious and persevering, and took full advantage of the opportunities XXXIl which were presented to him, of which characteristic a strong instance’ is supplied by his bringing at once into practical application in this country the powerful aid to diagnosis in diseases of the chest afforded by the stethoscope, whose value he had full opportunity of appreciat- ing during his student career at Paris, as a pupil of Laennec. The frankness of his character is well shown in his treatment of different misunderstandings with professional brethren and others in the pages of his autobiography. He lays as much stress on what makes against himself as on the favourable points, so that where the impartial reader may hold that he was in the wrong he almost disarms hostile criticism at the moment when he arouses it. This frankness may very likely have been the outcome of deep religious conscientiousness, for the whole book, and especially the final chapter, gives evidence of his’ character in this respect. He knew how to do ree to others as well as to himself. The reforming instinct of Dr. Williams found material to work upon in the constitution and bye-laws of the Royal Society and the Royal College of Physicians. With respect to the Royal Society, he endeavoured to introduce extensive changes by removing the limit put on the number ot Fellows elected annually, and laid much stress on his conviction that, whereas the Royal Society was founded for the promotion of natural science, it had become a kind of club for the segregation of the créme de la créme among scientific men from the general mass. But, though a special committee was appointed to con- sider his proposals for reform, they reported in favour of the status quo. The changes which he proposed in the case of the College of Physi- cians were of a very sweeping character, as he was eager that all physicians of good repute should be able, without difficulty or delay, to obtain the Fellowship as the full completion of the membership. He wanted the College to take a more commanding position—to become a national institution, fairly entitled to stand at the head of the Medical Corporations of the country and to acquire the authority and influence in the State that should properly belong to it; and he considered that, in order to attain this position, it was necessary for the College to include within its roll of membership many who did not belong to it, though fully qualified, because the privileges of mere membership were small, especially in the case of provincial physicians. But in this case, also, Dr. Williams found no adequate support for his views among the governing body of the institution. ' His references to his family exhibit throughout many signs of a very affectionate nature, and one is glad to think that during his later years of ease and retirement such a man had fuller opportunities for enjoying domestic family life than among the bustle and engagements of a successful physician’s mid-career. XXXil1" The man was what his autobiography has shown. What was his” work? His chief claim on the memory of his fellow-Jabourers and the public is that he was prominent among those who helped to reduce the principles of medicine to a properly co-ordinated scientific system, and who laid the foundations of modern pathology. It is pleasant to think that this high claim was fully recognised in his own lifetime, as is shown by his appointment to the different posts of honour already mentioned. Ave Ga By the death of Mr. Nrwatt, which occurred in April, 1889, the Society has lost a Fellow whose labours and interest in the progress of instrumental astronomy have secured a notable progress, which has been utilized throughout the whole of the civilized world, his activity in this direction being in direct continuation of that of others to whom we owe in a large measure the renaissance of the optical art in England. One of the first telescopes made by Cooke, of York, in his early days was one of large aperture constructed for Mr. Hugh Lee Pattinson, F.R.S:, F.R.A.S., and this was almost the first commission for a large object glass he had received. It was in the satisfactory completion’ of this telescope that Cooke gave that sure promise of a combined optical and engineering skill which his whole life was destined to fulfil. Mr. Newall, in 1849, married a daughter of Mr. Pattinson, and, possessing the same interest in astronomical pursuits as Mr. Pattinson himself, frequently discussed with him the possibility of successfully constructing and mounting an object glass of a size much larger than any other in existence. When he saw in the Exhibition of 1862 the two large discs of crown and flint glass, manufactured by the Messrs. Chance, of Birmingham, he determined to acquire them, and try an experiment. The diameter of these discs was about 26 inches; the largest existing refractor at that time in acwual operation was the 16-inch at Pulkowa, and Mr. Newall determined to see whether or’ no it was possible to advance at one bound from an aperture of 16 inches to one of 25. This experiment was not a simple one, for the idea at that time was that even if a perfect object glass of such dimensions could be turned out by the optician’s skill, yet that its ‘flexure would render it practically useless for all fine astronomical purposes. 7 Our great optician, Cooke, was just as anxious to make this experi- ment as Mr. Newall himself, and he threw himself into the work with vigour. Ultimately the telescope was finished: Cooke had never made an object glass of which the definition was more perfect, while the admirable engineering skill displayed in the mounting and the ease XXXIV- and simplicity of its motions and working had never been surpassed. Mr. Newall had originally intended to erect this enormous telescope in some climate more favourable for astronomical investigations than our own. Madeira, Egypt, and Malta were thought of, but it was first of all necessary to erect it not far from York in order that various experi- ments might be gone through without loss of time. It was, therefore, erected at Ferndene, Mr. Newall’s residence at Gateshead, and after its completion, circumstances having arisen which prevented its transference abroad, it remained there until Mr. Newall’s death. By Mr. Newall’s generosity it was practically at the disposal of any- one who had any special research to make for which a large aperture was indispensable. The writer of this notice would here acknowledge the many opportunities which were afforded him of making such observations, and also for the graceful hospitality with which these opportunities were accompanied. The success of this experiment at once changed the aspect of the optical art in all countries. The 26-inch at Washington, the 27-inch at Vienna, and the 36-inch in California are the direct descendants of the 25-inch at Gatestead. Before his death, Mr. Newall was anxious that the telescope should be removed to a more favourable locality, and it was offered by him to and accepted by the University of Cambridge. It is to be hoped that the scientific responsibilities which the University accepts with the instrument will be amply fulfilled. It may be well understood that the practical sagacity, unswerving purpose, and scientific habit of mind which had led to the conception and final carrying out of such an experiment as this, im alliance with the elder Cooke, would prove fruitful in other fields. Mr. Newall was not only a successful manufacturer, but he may be regarded as one of the chief founders of one of the most important of our modern national industries. In that part of his business which had to deal with wire rope, he found an unmechanical method of working; he left one which is simply perfect, and, as a result, wire ropes of his con- struction are now found all over the world: the double process of making the strands and then combining them being entirely avoided, while the wires retain all their original strength, as they remain untwisted. He was among the first, if not the first, to see and subse- quently demonstrate that the whole question of submarine telegraphy could only be settled by encasing the conducting wires with ropes ~ similar to those he was constructing for other purposes. This, of course, necessitated the use of an insulating material, and Mr. Newall was among the first in this country to study the properties of gutta- percha, insulating the conducting wires by the material, and then. surrounding and encasing them mh strong wire rope. The Seats successful cable laid from Dover to Cape Grisnez, in 1851, XXKV was manufactured by Mr. Newall. After this successful experiment, of course greater lengths were tried. Ships were specially constructed for cable laying, and arrangements adopted for securing the greatest facilities in paying out. Mr. Newall’s sagacity was again shown, and he at once invented methods which have never been improved upon, and which are now universally adopted. In the tank in which the cables were coiled, a cone occupied the centre, and effectually prevented kinks in the paying out, while a “drum brake” was inserted in the paying out apparatus to prevent all undue strains. It has been well said :— “To have established a new industry, to have taken an active part in securing a triumph of applied science which will modify the history of the world, and to have led the way in the development of the refracting telescope is a record of achievement to which few attain, but which does bare justice to the life-work of Robert Stirling Newail.” Mr. Newall was born in 1812. He was D.C.L. of Durham Univer- sity, and was elected a Fellow of this Society in 1875. : Jt Neils JoHN Percy, M.D., who died on the 19th of June last, was born at Nottingham, on the 23rd of March, 1817. At an early age he entered the Medical School of the University of Edinburgh, where at twenty- one he took the degree of M.D. He then studied in Paris, making the acquaintance of the leading French chemists of the time, who doubtless directed his mind towards the line of work to which his life was mainly devoted. He practised medicine at Birmingham for a few years, where, coming in contact with directors and managers of works, he was led to take special interest in metallurgy. It is, per- haps, worth remembering that the connexion between therapeutics and metallurgy has been traditional, and that the critical period of both was the middle of the 16th century, when Paracelsus attempted to introduce order into the science of medicine and Georgius Agricola strove to establish the art of metallurgy on a sound basis. Dr. Percy’s first paper was entitled a ‘“‘ Notice of a New Hydrated Phosphate of Lime,” and his second, dealing with the ‘“‘ Management of Monkeys in Confinement,” was printed in 1844. It was followed by other papers on medical subjects, but such work soon gave place to the systematic study of metallurgy, in which he might fairly say with an old writer: ‘“ An indefatigable labour, the closest inspection, and hands that were not afraid of the blackness of charcoal”? had been his “chief masters.” There was, indeed, little else than his own patient research to guide him, for the literature of metallurgy up to the time he wrote was sparse in the extreme, as may be gathered from the fact that when Cramer, himself a doctor of medicine, pub- - XXXV1 lished in 1754 his “‘ list of the chief English authors (about thirty in all) who have treated of minerals and metals,” none had written a treatise of metallurgy worthy of the name, though there were many detached monographs of value and a few papers in the ‘ Philosophical Transactions of the Royal Society.’ In the period which elapsed, - nearly a century, between the publication ‘of Cramer’s book and the time when Dr. Percy accepted the chair of metallurgy in the Royal School of Mines and began to teach, the most noteworthy contribu- tions to metallurgical literature were Bishop Watson’s Essays. These appeared in 1782, and are fragmentary, but, as Dr. Perey said, “ are elegantly and lucidly composed, and I never take them up but with increasing pleasure.” In 1861 Dr. Percy published the first volume of his treatise on ‘ Metallurgy,’ which he dedicated “ with sincere respect and affectionate regard” to Faraday. This work, which he calls the “‘ task of his life,” developed into a series of volumes con- taining 3,500 octavo pages. it is on this treatise that his reputation mainly rests, and we cannot doubt but that it willbe enduring. The writings of Pliny in the Ist century, of Geber in the 8th, and of Agricola in the 16th, may still be read with profit side by side with the modern work of Karsten, Gay-Lussac, Berzelius, Le Play, Plattner, Deville, and Holley, and it is with these metallurgists that Perey takes his place. Huis writings differ in many ways from those of his predecessors in any country. He was forcibly impressed with the fact that metallurgical problems demand for their successful investi- gation the exercise of the highest analytical skill, and involve con- siderations worthy of those who delight in transcendental inquiries. He effectively quotes Réaumur’s remark, ‘“‘l’utile bien considéré a toujours du curieux, et il est rare que le curieux bien suivi ne méne pas 4 l’utile.” The distinctive character of his metallurgical treatises arises from the care with which he examined the relations of the metals to other elements and to each other. While his predecessors unhesitatingly accepted the statements of earlier writers or showed a tendency to deduce from analogy what these relations would be, he made the proper- ties of metallic compounds the subject of careful experiment and em- bodied the results in his books, which form a record of great value, and one that teems with suggestions for future investigators. 'The excel- lence of the chemical purtions of his books gives them great value as works of reference quite apart from the accurate and elaborate de- scriptions they contain of typical metallurgical processes. These were in all cases prepared by the best men he could find, usually his own students, who were actually engaged in conducting the operations they describe. Such aid was always fully acknowledged. One remarkable feature of these books is that almost every woodcut may be con- sidered to be an accurate though small mechanical drawing, and it is XXXVI _only measurable drawings of this kind which are really useful in practice. In criticising his writings it may perhaps be said that his dread of mere empiricism and his intolerance of inaccuracy often led him to magnify points which now seem to be somewhat trivial, and he sometimes withholds the expression of his own opinion when the reader has fairly a right to expect his guidance and would be grateful for . the support of his authority. Of all his work that relating to iron and steel is perhaps the most important, and it began early in his metallurgical career with an elaborate piece of analytical work. The first International Exhibition, of 1851, contained a very extensive and highly interesting series of British iron ores, collected with great labour and at considerable ex- pense by Dr. Percy’s friend, Mr. H. 8. Bakewell, of Dudley, and after- wards presented by him to the Geological Museum in Jermyn-street. Mr. Bakewell placed at Dr. Percy’s disposal] the sum of £500 towards defraying the cost of analysing the more important of these ores. The work was completed by Dr. Percy with but slender aid from Govern- ment, and the results are embodied in his treatise on Iron and Steel, which was published in 1864. They have rightly been described as the first serious attempt at a survey of our national resources as regards ores of iron. With regard to the actual extraction of iron: from its ores, his services were not less important. In 1855 the fact was established that pig iron from the blast furnace contains the greater part of the phosphorus originally present in the ore. Dr. Percy pointed out that phosphorus is not eliminated to a sensible degree in the Bessemer process, as it is in the old process of puddling; and he was of opinion that if the Bessemer process was to be ‘generally applicable in this country, it must be supplemented by the discovery of a method of producing pig iron sensibly free from phosphorus and sulphur with the fuel and ores which are now so ex- tensively employed in our blast furnaces.” The practical solution of the problem of eliminating phosphorus in the Bessemer converter, and the wide adoption of a process of truly national importance, are the outcome of Dr. Percy’s teaching, for the problem was solved by three of his pupils. The delivery of his eloquent address in 1886, as President of the Iron and Steel Institute, fittingly ended the active portion of his labours with regard to these metals. His most noteworthy addition to practical metallurgical processes was described in a paper written by him in 1848, and published in the same year in a journal called ‘The Chemist.’ A translation of this paper reached a distinguished Austrian, who introduced, at Joachimsthal, the process now known as that of von Patera, which depends on the solubility of chloride of silver in hyposulphite of soda. Harly in 1884 this process was modified in America, by Mr. E. H. Russell, in order to render it applicable to ores poor in silver, which Jee SSS SSS SSS SS SS hn SAIS FAR I I. pms en A i gS eigen XXXVIil also contain a considerable quantity of base metal. Those who have. seen this process as now conducted in the Western States of America will appreciate the importance of Dr. Percy’s original suggestion. His contributions to our knowledge of metallic alloys were of special value, and he discovered the alloy of copper and aluminium, now known as aluminium-bronze. He concluded the introductory lecture which he delivered at the Royal School of Mines, more than a quarter of a century ago, by pointing out that ‘in proportion to the success with which the metallurgie art is practised in this country will the interests of the whole population, directly or indirectly, in no inconsiderable degree be promoted.” The recognition of this fact appears to have steadily guided him, and his best services were always at the disposal of the Government and were freely used, as will be seen from the long list of Royal Commissions and departmental inquiries upon which he served. The first of these was the Committee appointed, in 1861, by the Secretary of State for War, to inquire into the “ Application of Iron for defensive purposes.” This continued its labours for four years, and was followed by a Special Committee appointed in 1867, to inquire into “ Gibraltar” shields. He was also a member of the Royal Commission appointed in 1871, “to inquire into several matters relative to Coal in the United Kingdom,” and of the Royal Commission of 1875, which investigated “the cause of the Spontaneous Combus- tion of Coal in Ships.”’ He resigned his chair at the Royal School of Mines in 1879, but he continued to hold the office of Lecturer on Metallurgy to the Advanced Class of Artillery Officers, at Woolwich. He was also Superintendent of the Ventilation, Warming, and Lighting of the Houses of Parliament. In both of these appointments he took great interest until his last illness. Dr. Percy collected with great care a series of metallurgical specimens to illustrate special points of interest relating to the manufacture and uses of metals. ‘“ From the study of it,” he said, ‘‘I have myself derived much instruction. There are no Specimens which, in my judgment, are more instructive than such as exhibit defects which have appeared either in the process of manu- facture or in the use of metals.” This collection was formed while Dr. Percy was at Birmingham and during the period of twenty-nine years he was Lecturer on Metallurgy at the Royal School of Mines. The specimens are of great interest and value, and, as in many cases they represent obsolete processes, no similar specimens could again be obtained. They are all minutely described by labels, many of which bear incidental references to Dr. Percy’s Treatise on Metallurgy, to official reports, and to technical literature. It may safely be asserted that no existing metallurgical collection can com- pare with this in interest and importance. It is fortunate, therefore, XXX1X that it will not be dispersed, but, in accordance with the wishes of Dr. Percy’s family, will be preserved in connexion with the School of Mines, where he taught so long, and exhibited to the public at South Kensington, as the ‘“‘ Percy Collection.” The most cursory examination of his writings will serve to show the rigid precision with which he wrote. Sometimes when his sympathy or indignation was aroused he would adopt a more florid though not less effective style, of which it would be difficult to find more characteristic examples than the two extracts here placed in conjunction, both relating to the exhaustion of our national supply of coal, and both being exponents of his patriotic wishes for the wel- fare of his country. Speaking of a well-known coal-field, he says, “This magnificent bed of coal has been most barbarously treated. The pits have generally been worked by contractors under the super- intendence of viewers, called ground bailiffs. In consequence of the rapacity and rascality of many of the former, and of the ignorance, inattention, and fraudulent connivance of many of the latter, an enormous amount of coal has been irremediably lost to the nation.” After an interval of ten years he said, in concluding his Presidential Address at the Iron and Steel Institute, ‘There is a question which must often occur to us, namely, what will Great Britain be when our vast reservoir of material force, coal, is exhausted . . . . The time must come when, in consequence of that exhaustion, Great Britain will cease to be a great manufacturing nation, . . . but, however mournful and unwelcome this proposition may be, we have the satisfaction of knowing that we are now laying the foundation of prosperous and mighty kingdoms in various parts of the world which we hope will be the strongholds of virtue, of order, and of freedom . . . . The glory of old England may, after all, not depart ; on the sites of the soot-stained Birminghams and Manchesters new and splendid cities may arise where the merchant princes, of Anglo-Saxon descent, from the remotest parts of the globe shall re- joice to dwell and end their days in peace.” Dr. Percy’s public utterances were but few, and the above formed a part of the last of them. He led a retired life and was hardly ever seen at Scientific Societies, though he was frequently at the Athenzeum and was well-known at the Garrick Club. _ He married in June, 1839, Miss Grace Mary Piercy, the only daughter of Mr. J. HE. Piercy, of Warley Hall, near Birmingham. Those who knew him best feel that the loss of his wife, in 1880, greatly changed him. | Official recognition of his admirable labours there is none to record, but many Scientific Societies and Institutions conferred on him their membership. He was elected a Fellow of the Royal Society in 1847, and served on its Council in 1857-59 ; he was awarded the Millar Prize xl of the Institution of Civil Engineers, of which body he was one of the few Honorary Members. He received the Bessemer Gold Medal of the Iron and Steel Institute in 1877, and, in 1889, the Prince of Wales, on the recommendation of the Council, awarded him the Albert Medal of the Society of Arts. The notification of the honour reached him on his death-bed, and he received it with the charac- teristic remark, almost his last, ‘“‘ My work is done.” W. C. R-A. Apmirat Sir Rosert Spencer Rosinsoy, K.C.B., was the youngest son of the late Venerable Sir John Robinson, Archdeacon of Armagh. Born in January, 1809, he entered the Navy 6th December, 1821, served in the boats of the “Sybille” in an affair with pirates in 1826, and becamea Lieutenant in 1830. He attained the rank of Commander in 1838, and that of Captain in November, 1840. After commanding in the latter rank H.M.S. “ Arrogant,” ‘ Colossus,” and “ Royal George” on foreign service, he was Captain of the Steam Reserves at Plymouth and Portsmouth for four years, until he became a Rear- Admiral, in 1860. He was a Commissioner to enquire into the management of the Royal Dockyards in the same year, and was appointed Controller of the Navy on 7th February, 1861, an office he held until 1871. The latter three years of this period he was also a Lord of the Admiralty. He retired in 1871, and died on the 27th July, 1889. He was the author of a treatise on the Marine Steam Engine. Sir Spencer was at the head of the constructive department of the Admiralty during a period of momentous change, when iron was being introduced in place of wood; the powers of the steam engine were being rapidly developed, and armour-plating was becoming a necessary protection to the battle ship. Having already profited by a scientific training, superior to that which in his day was common among naval officers, in one of the intervals of his naval employment by the Admiralty, he found an opportunity of entermg the marine engine works of the late Mr. Robert Napier, on the Clyde, and there practically acquired the art of using engineering tools and of conducting factory work—acquirements which proved invaluable to him afterwards during his superintendence of the Steam Reserves, and subsequently of H.M. Dockyards. His service at the Admiralty, as Controller of the Navy, was distinguished by a combination of ability and devotion to duty well adapted to accom- plish the solution of the great naval problems which it was his lot to grapple with, and indeed to solve. It was due to his influence, and largely to his initiative, that the British Navy became possessed of a fleet of iron-built armoured ships long before the necessity for giving up wood-built ships of that class was realised in other countries. He similarly anticipated foreign navies by the early introduction of the xli compound marine engine; and throughout his period of service the British Navy led the way in the development both of armour and of ordnance. He was an accomplished linguist, and possessed great literary ability and aptitude. Waite JW, CHARLES Spence Bare was born at Trenick, near Truro, on the 16th of March, 1818. He was the elder son of Mr. Charles Bate, who practised asa dentist at Plymouth. He received his education at the Truro Grammar School, and afterwards was for two years in the surgery of Mr. Blewett. He then gave himself to the study of dentistry with his father, and on becoming qualified, commenced practice in Swansea, in 1841. Here he acquired a good practice, and by association with the scientific men of the place his taste for those branches of natural history with which his name was afterwards so closely associated was fostered and developed. After a residence of ten years in Swansea, Mr. Bate returned to Plymouth, where he succeeded to the dental practice of his father. In his profession he . stood very high, enjoying a great repute for skill both in its purely surgical and mechanical branches. He contributed numerous papers on dental subjects to the ‘ Lancet,’ the ‘ Medical Times and Gazette,’ the ‘ British Journal of Dental Science,’ and the ‘ Transac- tions of the Odontological Society.’ He was President of the British Dental Association in 1883, of the Odontological Society of Great Britain in 1885, and of Section XII of the International Medical Congress held in London in 1881. As a naturalist Mr. Bate’s favourite study was the Crustacea, and in the development and morphology of this group he did most of the work by which his name will long be remembered. The work which first brought his name prominently before the scientific world, was the ‘ Natural History of the British Sessile-Eyed Crustacea,’ in the production of which he was associated with Professor Westwood. The difficulties of a work like this—embracing as it did so large a field in which but little _had previously been done—were very great, and it cannot be wondered at that some of its conclusions. and observations have already been superseded by others made under more favourable circumstances and with all the advantages of added experience and - increased facilities of research. Still, however, this work remains the standard authority on its branch of Carcinology. Mr. Bate’s most recent work was his report on the Crustacea Macrura of the “Challenger”? Expedition. This laborious and comprehensive work occupies two large volumes of the Official Report of the Expedition, and is illustrated by 150 lithographic plates, almost all of them drawn by Mr. Bate. These are admirably done and of themselves ~ form an enduring monument to the consciertious industry and Se ae tO xh scientific acumen of the author, while the descriptive part of the work is marked by that thorough familiarity with the subject, which charac- terised his previous great work on the Sessile-Eyed Crustacea. Mr. Bate contributed to the ‘ Proceedings of the Royal Society ’ papers ‘On the Development of Carcinus Meenas” (1856-57), and ‘“‘Qn the Development of the Crustacean Embryo and the Variations of Form exhibited in -the Larve of 38 Genera of Podophthalmia”’ (1876). In the ‘ Philosophical Transactions,’ 1858, appeared a memoir, “‘ On the Development of Decapod Crustacea.”’ These papers well show the interest which he took in the remarkable transforma- tions undergone by the young of Crustacea, and the important share which he had in the elucidation of them. To the ‘ Proceedings of the — Zoological Society,’ —of which Society he was elected a Correspond- ing Member in 1865--Mr. Spence Bate contributed several papers descriptive of new species of Crustacea. Mr. Bate was one of the founders of the Devonshire Association for the Advancement of Science, Literature, and Art, was its first Senior General Secretary in 1862, and its President in 1863. In this Society he always took the keenest interest, and he contributed to its Proceedings many papers, chiefly connected with local arche- ology. He was a most active member of the Plymonth Institution, was twice President of that body, and delivered before it many lectures on biological and archeological subjects. He was also deeply interested in the Fine Art Society of Plymouth, and being a good amateur artist in water-colours, he contributed frequently to the exhibitions held by that Society. About two years before his death Mr. Bate partially retired from his dental practice, having previously purchased a country residence, — —‘‘ the Rock,” at South Brent—where he died aftera brief illness on Monday, the 29th of July, 1889, aged 71 years. He was twice married. His first wife was Miss Emily Amelia Hele, of Wellad Lake, near Ashburton. His second wife survives him. He also leaves two sons of the first marriage,—Captain C. McGuire Bate, of the Royal Engineers, and Dr. Hele Bate, of London; and a daughter, Miss Emily Harriet Bate. G. SiB; Joun Freprric Bareman, a son of Mr. John Bateman, of Ockbrook, Derbyshire, was born the 30th of May, 1810. His mother was the daughter of the Rev. Benjamin La Trobe, an eminent Moravian minister in Yorkshire, in compliment to whom his grandson, late in life, assumed the name of John Frederic La Trobe Bateman. At fifteen years of age he was apprenticed to a surveyor and mining engineer of considerable practice at Oldham, and made such progress that he was able to commence business on his own account, as an xl engineer, at Manchester, in 1833. Here he had the good fortune to make the acquaintance of the eminent engineer, Mr. Fairbairn (after- wards Sir William Fairbairn, Bart., F.R.S.), who quickly saw the young man’s merits, and formed a warm friendship with him, which resulted some years later in the marriage of Mr. Bateman with Mr. Fairbairn’s daughter Anne. In 1835 Mr. Fairbairn was applied to by the millowners on the River Bann, in County Down, Ireland, to examine the locality, and to report on the best means of improving the water power, which was in a very unsatisfactory state. Knowing that his young protégé had paid attention to water questions, he thought this would be a good means of bringing him forward, and he accordingly undertook the commission, associating Mr. Bateman with him in the work. In January, 1836, a report was published, signed by Mr. Fairbairn and Mr. Bateman jointly, giving full scientific calculations as to the hydraulic elements of the case, and recommending the construc- tion of large reservoirs, and other works. An Act of Parliament was at once obtained, and in the course of the three following years the works were carried into execution, the designing and construction of the whole being entrusted, at Mr. Fairbairn’s request, entirely to Mr. Bateman. This work established Mr. Bateman’s reputation as a hydraulic engineer, and led a few years later to his employment on a much larger and more important work, namely, the provision of an entirely new water supply, on the largest scale, for the city of Man- chester. The town had previously been supplied by a private Company from sources near the town, but about 1844, when public attention became prominently directed to the sanitary condition of large towns, the supply was found so defective, that it was evident some extensive improvements must be made, and in that year Mr. Bateman was requested to advise the Company generally on the matter. In the course of his work on the Bann Reservoirs, and in some subsequent practice in the Lancashire district, he. had paid great attention to the mode of supply by impounding the rainfall in hilly districts, and to the data necessary for determining the capabilities of the system. He had become acquainted with the country surrounding Manchester, and had formed a strong opinion that the best source of supply would be by an application of the system to the hilly district lying to the east of the town, and in June, 1846, he made a report strongly recommending thisscheme. He said:—‘‘ Within ten or twelve miles of Manchester, and six or seven miles from the present Gorton Reservoir (then supplying the town), there is a tract of mountain land abounding with springs of the purest quality. The physical and geological features offer such peculiar facilities for the collection, storage, and supply of water for the use of the towns in the plains xliv below, that I am surprised they should have so long been over- looked. There is no other district within reasonable limits, nor any source from whence water may be obtained, which will bear compari- son with it.” The project as thus designed was on a small scale, suited to a Company who could not contemplate a large expenditure ; but even this was considered too bold, and the measure, after encountering violent Parliamentary opposition, was abandoned. A year or two afterwards the Corporation of Manchester determined to take the supply into their own hands, and Mr. Bateman was called in again by them. This time, however, being encouraged by the larger views that prevailed, he laid out a much bolder scheme, going at once into the heart of the district known as the valley of Longdendale, to which his views had already been directed. His plan was adopted by the Corporation, and was sanctioned by Acts of Parliament in 1847 and 1848. The municipality having arranged to buy up the old Company, the new works were put in hand. At first only such portions were executed as were absolutely necessary, but they were enlarged from time to time, as the demand increased, and it was not till 1877 that Mr. Bateman could report that they were completed, and that the water-bearing capabilities of the district were fully realised. The work thus created under Mr. Bateman’s hand was certainly a magnificent specimen of engineering power and skill. It consisted chiefly of a series of large artificial impounding lakes, extending over seven miles of the valley. Their aggregate content was 735,000,000 cubic feet, and they furnished water for nearly a million of people, as well as a very large and ample water compensation to the millowners on the stream. The total expenditure was about £3,000,000. In addition to the reservoirs, the works comprised a multitude of subsidiary works for conveying and distributing the water, and for the regulation of the streams. Among these were several novel hydraulic contrivances of a high order; one an arrangement for the automatic separation of the clear from the peaty water (the former being sent to the town, and the latter stored for compensation), and another a mechanical gauge basin, by which the quantity of compen- sation water could be actually measured at any moment with great accuracy, for the satisfaction of the millowners. Mr. Bateman was always justly proud of this his first great work ; and one of the latest of his life’s occupations was to prepare a hand- some volume,* putting fully on record its entire history, and giving an * “WVistory and Description of the Manchester Waterworks.” By Jokn Frederic La Trobe Bateman, F.R.SS. L. and E. London and Manchester, 1884. xlv excellent description, profusely illustrated with engravings, of the various engineering constructions it contained. In 1852 Mr. Bateman was applied to by the Corporation of Glasgow to advise them in regard to their waterworks. Many schemes had been proposed, but Mr. Bateman recommended them to obtain a supply from one of the most celebrated of the Scotch lakes, Loch Katrine. Parliamentary sanction was obtained in the session of 1854-5, and the works were finished in 1859. The loch, lying 367 feet above the sea, forms a large reservoir for the catchment basin above it, in which the rainfall is very large. To fit the lake for supply purposes, its level was raised 4 feet, and arrangements were made so that it could be drawn down 7 feet in all, giving an available storage of 5600 millions of gallons. The water is conveyed to the town by a conduit twenty-six miles in length. In 1855 he was requested by the British Association to prepare a general report on water supply, and, in pursuance of the request, he presented, at the meeting at Glasgow, in September of that year, a communication ‘‘On the present state of our knowledge ou the Supply of Water to Towns. By John Frederic Bateman, F.G.S.” It was a paper of some length and considerable merit. After stating the general nature of the problem, and giving a historical outline of previous measures, it enumerated the various sources from which towns could be supplied, and discussed their comparative merits, adding examples and statistical data in illustration. In 1861, when the British Association held their meeting at Man- chester, under the Presidency of Mr. Fairbairn, his son-in-law undertook the post of President of the Mechanical Section. Mr. Bateman was elected a Fellow of the Royal Society on June 7, 1860. He served on the Council in the years 1865 and 1866. At the end of 1869, the Viceroy of Egypt invited the Royal Society to send a representative to be present at the opening of the Suez Canal, and on the recommendation of the President, General Sir Edward Sabine, Mr. Bateman was selected for the duty. On his return he wrote to the President a long report of his visit, which was read to the Society on the 6th January, 1870, and was published in full in the ‘ Proceedings.’ Mr. Bateman gave an interesting historical notice of the negotiations and proceedings which had been going on for many years on the subject, and had terminated in the successful completion of the enterprise. He added a general description of the Canal and of the ceremony of its opening, and he concluded with the following eulogium :— “The Canal must be regarded as a great work, more from its relation to the national and commercial interests of the world than from its engineering features. In this light it is impossible to over- estimate its importance. It will effect a totai revolution in the mode xlvi | of conducting the great traffic between the Hast and the West, the beneficial effects of which, I believe, it is difficult to realise. Itis m i this sense that the undertaking must be regarded as a great one, and ‘ll its accomplishment is due mainly to the rare courage and indomitable | perseverance of M. Ferdinand de Lesseps, who well deserves the | respect he has created and the praises which have been bestowed. | A channel of water communication has been opened between | the East aud the West which will never sine be closed so long as | | mercantile property lasts or civilisation exists.” The waterworks which Mr. Bateman had constructed for Manchester and for Glasgow, although both of gigantic magnitude, did not satisfy his ambition. He saw the treasures of water which were ad annually wasted by floods in mountain districts, and he longed to i hie originate some great schemes for utilising them. He said :— ‘ q “T could never see the wisdom of the view which would confine the supply of water to the towns and places which lay within any Biied particular watershed. Where the water was most abundant it was aie generally the least wanted; and towns had grown up where it was . often difficult to obtain this essential contribution to life and prosperity. To my mind, the idea of confining such places to their own watersheds, and preventing their going for what they wanted where there was enough and to spare, was absurd. As i well might it be urged that the coal produced in the neigh- ] bourhood of Newcastle should all be consumed in the Valley of | the Tyne, and none of it conveyed to London or the Valley of the Aid Thames.” tia, About 1869 an opportunity offered for exemplifying this principle. i ij There had been a good deal of discussion as to the water supply of London, and Mr. Bateman designed a project for supplying the metropolis from a mountainous district in North Wales, where the rainfall was very large. He proposed to collect the water in artificial reservoirs, and to bring it to London by conduits above 180 miles long, delivering it at such a level as would give the supply } entirely by gravitation. The plan was submitted to a Royal Com- ii mission, of which the Duke of Richmond was Chairman, and who qi reported in 1868. They expressed a high opinion of the plan, but i | * decided that, for the present, at least, the metropolis did not require | SO expensive a measure. 4) Some years later, however, Mr. Biomaat s ambition was gratified 1 in another way. When, in 1877, he reported to the Corporation of bi Manchester that the waterworks were finished, he did not conceal from them that he had for some time been anxious about the future, a inasmuch as the enormous growth of the town was fast outrunning © mii the capacity, great as it was, of the Longdendale source of supply. | He reverted to his former principle of resorting to mountain districts, eS oe xlvi where large quantities of water were running to waste, and he found this eminently the case in the Lake District of Cumberland. The Corporation took up the idea, and in 1879 an Act was passed for obtaining a large supply from Thirlmere by a conduit 100 miles long. In this Mr. Bateman was associated with Mr. George Hill, of Man- chester, by whom the works are now being carried ont. Mr. Bateman’s knowledge of water supply involved several points of original scientific investigation. The chief one was on the subject of rainfall and its accompanying phenomena. When he undertook the work of the Bann Reservoirs, in 1835, he was surprised to find how little trustworthy information was available as to the two points of greatest importance, namely: (1) the rainfall upon the surface, and (2) the proportion of this that flowed off in the streams and rivers. With laudable zeal and industry he determined to remedy this difficulty for the future by establishing on the ground a regular system of observations on both points. After this time, in the course of his Manchester practice, he was engaged, more or less directly, on several other proposals or undertakings which had to do with water supply in the neiglibourhood; and in every one of these he followed up his enquiry either by obtaining the best records available, or making new sets of observations entirely his own. The knowledge gained in these enquiries emboldened him to read two papers before the Literary and Philosophical Society of Man- chester, viz. :— ‘Observations on the Relation which the fall of Rain bears to the Water flowing from the Ground” (read 6th February, 1844); and “ Report of the Committee for superintending the placing of Rain Gauges along the lines of the Rochdale, Ashton-under-Lyne, and Peak Forest Canals. With observations, &e.” (read 18th March, 1845). These early papers contained valuable facts, and showed consider- able power of scientific reasoning upon them. But the subject was a favourite one with Mr. Bateman during his whole career. He seldom wrote a report on water undertakings without giving explana- tions thereon, and, as late as 1883, he wrote a special paper for the Victoria Institute, entitled ‘‘ Meteorology and Rainfall.” He was a great advocate for the use of soft water; and one of his later works, in the Colne Valley. near Watford, was remarkable for his successful application of the elegant chemical principle of the late Dr. Clark, for softening hard chalk water by lime; a great boon to the populations supplied. In 1878, Mr. Bateman was elected President of the Institution of _ Civil Engineers, an office which he filled two years. In his opening address, delivered loth January, 1878, in addition to the usual professional topics, he enlarged on the subject of engineering educa- tion, pointing out particularly the necessity for the cultivation of Ht i] at | ; : eit a Li (KN xlvili- science in those branches that bear on the operations of the Sa sion. It has only been possible here to mention a few of the works by which Mr, Bateman has been most widely known, but his practice was very large, and he occupied a high position in his profession. Mr. Bateman died at his residence, Moor Park, Farnham, on the 10th of June, 1889. Wor: INDEX To Abrus precatorius (jequirity), physio- lovical action of the active principle of the seeds of (Martin and Wolfen- den), 94. the toxic action of the albu- mose from the seeds of (Martin), 100. Absorption-spectra of oxygen and some of its compounds, notes on the (Live- ing and Dewar), 222. Acton (E. H.) the assimilation of car- bon by green plants from certain organic compounds, 118. Adair (J. F.) and R. Threlfall, on the velocity of transmission through sea- _ water of disturbances of large ampli- tude caused by explosions, 496. Address of the President, 449. Air, the accurate determination of car- bonic acid and moisture in (Haldane and Pembrey), 40. Air-bladder and Weberian ossicles in the Siluride, the (Bridge and Haddon), 309. Aitken (John) elected, 175. admitted, 2538. Albumose from the seeds of Abrus pre- catorius, the toxic action of the (Martin), 100. Allport (S.) and T. G. Bonney, report on the effects of contact metamor- phism exhibited by the Silurian rocks near the town of New Galloway, in the southern uplands of Scotland, 193. Anatomy of fishes, contributions to the (Bridge and Haddon), 309. Andrews (T.) electro-chemical effects on magnetising. iron. Part III, 176. Anniversary meeting, 448. Assimilation of carbon by green plants from certain organic compounds (Acton), 118. Atomic weight, zirconium and (Bailey), 74. of gold, revision of the, (Mallet), 71. Auditors elected, 385. report of, 448. Auwers (Georg Friedrich Julius Arthur) admitted, 1. . its VOL. XLVI. Bacteria, the ferment-action of (Brun- ton and Macfadyen), 542. Bailey (G. H.) zirconium and its atomic weight, 74. Balfour (Arthur James) admitted, 384. Ballard (Edward) elected, 175. admitted, 253. Barium sulphate, as a cement in sand- stone (Clewes), 363. — deposits of, from mine-water (Clowes), 368. Basset (Alfred Barnard) elected, 175. admitted, 253. Bate (Charles Spence) obituary notice of, xli. Bateman (John Frederick La Trobe) obituary notice of, xlii. Bateson (W.) on some variations of Cardium edule, apparently correlated to the conditions of life, 204. Batteries, contributions to the chemistry of storage. No. 2 (Frankland), 304. Battery, a new form of gas (Mond and Langer), 296. Bean and pea, on the tubercles on the roots of leguminous plants, with special reference to the (Ward), 431. Beard (J.) on the early development of Lepidosteus osseus. Preliminary notice, 108. ; Bonney (T. G.) and S. Allport, report on the effects of contact metamor- phism exhibited by the Silurian rocks near the town of New Galloway in the southern uplands of Scotland, 193. Bottomley (J. T.) and A. Tanakadate, note on the thermo-electric position of platinoid, 286. Boys (C. V.) on the Cavendish experi- ment, 253. Bridge (T. W.) and A. C. Haddon, con- tributions to the anatomy. of fishes. J. The air-bladder and Weberian ossicles in the Siluride, 309. Brooke (Sir William O’Shaughnessy) obituary notice of, xviii. Brown (Horace T.) elected, 175. admitted, 253. Brunton (T. L.) and A. Macfidyen, the ferment-action of bacteria, 542, | INDEX. Bunbury (Sir Charles James Fox) obi- tuary notice of, xiii. Cameron (Sir C. A.) and J. Macallan, researches in the chemistry of selenic acid and other selenium compounds, 13. Candidates for election, list of, 1. Carbon, assimilation of, by green plants from certain organic compounds (Acton), 118. Carbonic acid and moisture in air, the accurate determination of (Haldane and Pembrey), 40. Cardium edule, on some variations of, apparently correlated to the condi- tions of life (Bateson), 204. Cassie (W.) on the effect of temperature on the specific inductive capacity of a dielectric, 357. Catalogue of Scientific Papers, the Government and the publication of the, 455. Cavendish experiment, on the (Boys), 253. Chemical inquiry into the phenomena of human respiration (Mareet), 340. Chemistry of storage batteries, contri- butions to the. No.2 (Frankland), 304. of the urine of the horse (Smith), 328. Chlorine-water, on the rate of decom- position of, by light (Gore), 362. Clark (J.) protoplasmic movements and their relation to oxygen pressure, 370. Clark (Latimer) elected, 175. admitted, 253. Clarke (Colonel) elected an auditor, 389. Clowes (F.) barium sulphate as a cement in sandstone, 363. -—— deposits of barium sulphate from mine-water, 368. Cockle (Sir James) elected an auditor, 385. Conductors in the neighbourhood of a wire, note on the effect produced by, on the rate of propagation of elec- trical disturbances along it, with a determination of this rate (Thomson), i Copper and nitric acid, the conditions of the reaction between (Veley), 216. Council, nomination of, 384. election of, 459. Croonian lecture (Roux), 154. Cunningham (David Douglas) elected, 175. Dentition of Ornithorhynchus (Thomas), 126. Development of Lepidosteus osseus, on the early (Beard), 108. Dewar (J.) and G. D. Liveing, notes on the absorption-spectra of oxygen and some of its compounds, 222. Dickinson (W. L.) and J. N. Langley, on the local paralysis of peripheral ganglia, and on the connexion of different classes of nerve fibres with them, 423. Dielectric, on the effect of temperature ou the specific inductive capacity of a (Cassie), 357. f Dielectrics, specific inductive capacity of, when acted on by very rapidly ' alternating electric forces (Thomson), 292. Differential (linear) operators, on the interchange of the variables in certain (Elliott), 358. Donation Fund, grants from the, 473. Dunstan (W. R.) on the occurrence of skatole in the vegetable kingdom, 211. Election of Council and Officers, 459. of Fellows, 175. Electrical disturbances, effect produced by conductors in the neighbourhood of a wire on the rate of propagation along it of, with a determination of this rate (Thomson), 1. Electricity, voltaic, note on the develop- ment of, by atmospheric oxidation of combustible gases and other sub- stances (Wright and Thompson), 372. Electro-chemical effects on magnetising iron. Part III (Andrews), 176. Elliott (E. B.) on the interchange of the variables in certain linear differ- ential operators, 358. Ewing (J. A.) on time-lag in the mag- netisation of iron, 269. Explosions, on the velocity of transmis- sion through sea-water of disturb- ances of large amplitude caused by (Threlfall and Adair), 496. Farre (Arthur) obituary notice of, iii. Fellows deceased, 448. elected, 175, 449. number of, 469. Ferment-action of bacteria (Brunton and Macfadyen), 542. Fermentation of mannite and glycerin, on a pure (Frankiand and Fox), 345. Films produced by vaporised metals and their applications to chemical analysis (Hartley), 88. INDEX. hi Financial statement, 460. Fishes, contributions to the anatomy of. I. The air-bladder and Weberian ossicles in the Siluride (Bridge and Haddon), 309. Fletcher (Lazarus) elected, 175. admitted, 253. Fox (J. J.) and P. F. Frankland, on a | pure fermentation of mannite and | glycerin, 3495. France (KE. P.) appendix to paper on | descending degenerations following © lesions in the gyrus marginalis and gyrus fornicatus in monkeys, 122. Frankland (E.) contributions to the chemistry of storage batteries. 304. Frankland (P. F.) and J. J. Fox, on a pure fermentation of mannite and glycerin, 345. Galton (F.) elected an auditor, 385. Ganglia, peripheral, on the paralysis of, and on the connexion of ditterent classes of nerve fibres with | them (Langley and Dickinson), 423. Gas battery, a new form of (Mond and | Langer), 296. Gaskin (Rev. Thomas) obituary notice | Ofek Geikie (Dr.) elected an auditor, 385. Geological origin of terrestrial magnet- ism, on w possible (Hull), 92. Geometrical theorems, oncertain. No. 4 | (Russell), 376. Glycerin and mannite, on a pure fer- | mentation of (Frankland and Fex), 345. Gold, revision of the atomie weight of | (Mallet), 71. Gore (G.) determining the strength of liquids by means of the voltaic balance, 87. on the rate of decomposition of chlorine-water by light, 362. Government Grant of 4000/., account of | the appropriation of the, 469. Gray (Asa) obituary notice of, xv. Gyrus marginalis and gyrus fornicatus in monkeys, appendix to paper on | descending degenerations following © lesions in the (France), 122. Haast (Sir Julius von) obituary notice of, xxiv. Haddon (A. C.) and T. W. Bridge, con- | tributions to the anatomy of fishes. I. The air-bladder and Weberian ossicles in the Siluride, 309. Haldane (J. 8.) and M. 8. Pembrey, the accurate determination of car- | bonic acid and moisture in air, 40. No.2, | lecal | Hartley (W. N.) on films produced by vaporised metals and their applica- tions to chemical analysis. Prelimi- nary notice, 88. Hemsley (William Botting) elected, 176. admitted, 253. Hopkinson (J.) magnetic and other physical properties of iron at a high temperature, 87. Horse, the chemistry of the urine of the (Smith), 328. Hudson (Charles Thomas) elected, 175. — admitted, 253. Huggins (W.) on the limit of solar and stellar light in the ultra-violet part of the speetrum, 133. and Mrs. Huggins, note on the photographic spectra of Uranus and Saturn, 231, on the spectrum, visible and photographic, of the great nebula in Orion, 40, Hughes (Thomas MeKenny) elected, 175. Hull (E.) ona possible geological origin of terrestrial magnetism, 92. Human respiration, a chemical enquiry into the phenomena of (Marcet), 340. India-rubber, the physical properties of vulcanised (Mallock}, 238. Inductive capacity of a dielectric, on the effect of temperature on the specific (Cassie), 357. of dielectrics when acted on by very rapidly alternating electric forces, specific (Thomson), 292. Inoculations préventives, les. Croonian lecture (Roux), 154. Interchange of the variables in certain linear differential operators, on the (Elliott), 358. Tron, electro-chemical effects on mag- netising. Part III (Andrews), 176. magnetic and other physical pro- perties of, at a high temperature (Hopkinson), 87. — on time lag in the magnetisation of (Ewing), 269. (Jequirity), physiological action of the active priuciple of the seeds of Abrus precatorius (Martin and Woltenden), 94. the toxie action of the albumose. from the seeds of Abrus precatorius (Martin), 100. Jervois (Sir William F. D.) admitted, 384. a g ‘fa INDEX. Jodrell (Thomas decease of, 453. appropriation of the fund esta- blished by, 453. Joly (J.) observations on the spark discharge, 376. Jodrell Phillips) Kew Committee, report of, 474. Kirchhoff (Gustav Robert) obituary notice of, vi. Langer (C.) and L. Mond, a new form of gas batterv, 296. ’ Langiey (J. N.) and W. L. Dickinson, on the local paralysis of peripheral ganglia and on the connexion of ditterent classes of nerve fibres with them, 423. Lawes Agricultural Trust, establishment of the, 456. Leguminous plants, on the tubercles on the roots of, with special reference to the pea and bean (Ward), 481. Lepidosteus osseus, on the early de- velopment of. Preliminary notice (Beard), 108. Light, on the magnetic rotation of the plane of polarisation of, in doubly refracting bodies (Ward), 65. on the rate of decomposition of chlorine-water by (Gore), 362. in the ultra-violet part of the spectrum, on the limit of solar and stellar (Huggins), 133. Linear differential operators, on the interchange of the variables in certain (Elliott), 358. Liquids, determining the strength of, by means of the voltaic balance (Gore), 87. Liveing (G. D.) and J. Dewar, notes on the absorption-spectra of oxygen and some of its compounds, 222. Local paralysis of peripheral ganglia, on the, and on the connexion of different classes of nerve fibres with them (Langley and Dickinson), 428. Lockyer (J. N.) further discussion of the sun-spot observations made at South Kensington. A report to the Solar Physics Committee, 385. on the cause of variability in con- densing swarms of meteorites, 401. on the wave-length of the chief fluting seen in the spectrum of man- ganese, 35. Macallan (J.) and Sir C. A. Cameron, researches in the chemistry of selenic acid and other selenium compounds, 13. Macfadyen (A.) and T. L. Brunton, the ferment-action of bacteria, 542. Magnetic and other physical properties of iron at a high temperature (Hop- kinson), 87. rotation of the plane of polarisa- tion of light in doubly refracting bodies, on the (Ward), 65. Magnetisation of iron, on time-lag in the (Ewing), 269. Magnetising iron, _ electro-chemical effects on. Part III (Andrews), 176. Magnetism, on a possible geological origin of terrestrial (Hull), 92. Mallet (J. W.) revision of the atomic weight of gold, 71. Mallock (A.) the physical properties of vulcanised india-rubber, 233. Malus, an experimental verification of the sine law of (Spitta), 376. Manganese, on the wave-length of the chief fiuting seen in the spectrum of (Lockyer), 35. Mannite and glycerin, on a pure fer- mentation of (Frankland and Fox), 345. Marcet (W.) a chemical enqniry into the phenomena of human respiration, . 840. Martin (S.) the toxie action of the albumose from the seeds of Abrus precatorius, 100. and R. N. Wolfenden, physiologi- cal action of the active principle of the seeds of Abrus precatorius (jequirity), 94. Medals, presentation of the, 456. Metals, on films produced by vaporised, and their applications to chemical analysis (Hartley), 88. Metamorphism (contact) exhibited by the Silurian rocks near the town of New Galloway, in the southern up- lands of Scotland, report on the effects of (Allport and Bonney), 193. Meteorites, on the cause of variability in condensing swarms of (Lockyer), 401. Milne (John) admitted, 175. Mine-water, deposits of barium sulphate from (Clowes), 368. Monckman (J.) the specific resistance and other properties of sulphur, 136. Mond (L.) and C. Langer, a new form of gas battery, 296. Monkeys, appendix to paper on descend- ing degenerations following lesions in the gyrus marginalis and gyrus forni- catus in (France), 122. Nebula in Orion, on the spectrum, y INDEX. hu visible and photographic, of the great (Huggins and Huggins), 40. Nerve fibres, on the local paralysis of peripheral ganglia, and on the con- nexion of different classes of, with them (Langley and Dickinson), 423. Newall (Robert Stirling) obituary notice of, XXxiil. Nitric acid, the conditions of the reaction between copper and (Veley), 216. Obituary notices :— Bate, Charles Spence, xli. Bateman, John Frederic La Trobe-, xii. Brooke, Sir William O’Shaughnessy, XViil. Bunbury, Sir Charles James Fox, Xiil. Farre, Arthur, iii. Gaskin, Rev. Thomas, i. Gray, Asa, xv. Haast, Sir Julius von, xxiv. Kirchhoff, Gustav Robert, vi. Newall, Robert Stirling, xxxiil. Percy, John, xxxv. Rees, Owen, xi. Robinson, Admiral Sir Robert Spencer, all Stewart, Balfour, ix. Weldon, Walter, xix. Williams, Charles James Blasius, xxvi. Officers, nomination of, 384. election of, 459. Orion, on the spectrum, visible and photographic, of the great nebula in (Huggins and Huggins), 40. Ornithorhynchus, on the dentition of (Thomas), 126. Oxygen and some of its compounds, notes on the absorption-spectra of (liveing and Dewar), 222. pressure, protoplasmic movements and their relation to (Clark), 370. Paralysis, local, of peripheral ganglia, and on the connexion of different classes of nerve fibres with them (Langley and Dickinson), 423. Pasteur (M. L.) public recognition of his services to science and humanity, 253. Pea and bean, on the tubercles on the roots of leguminous plants, with special reference to the (Ward), 431. Pembrey (M. 8S.) and J. S. Haldane, the accurate determination of car- bonic acid and moisture in air, 40. Perey (John) obituary notice of, xxxv. Peripheral ganglia, on the local para- lysis of, and on the connexion of different classes of nerve fibres with them (Langley and Dickinson), 423. Photographic spectra of Uranus and Saturn, note on the (Huggins and Huggins), 231. Phymosoma varians, on (Shipley), 122. Plants, assimilation of carbon by green, from certain organic compounds (Acton), 118. Platinoid, note on the thermo-electric position of (Bottomley and Tanaka- date), 286. Polarisation of light in doubly refracting bodies, on the magnetic rotation of the plane of (Ward), 65. Poulton (Edward B.) elected, 175. admitted, 253. Presents, lists of, 61, 90, 132, 172, 249, 376, 443. President, address of the, 449. -Protoplasmic movements and. their re- lation to oxygen pressure (Clark), 370. Rae (Dr.) elected an auditor, 385. Rees (Owen) obituary notice of, xi. Respiration, a chemical enquiry into the phenomena of human (Marcet), 340. Robinson (Admiral Sir Robert Spencer) obituary notice of, xl. Roots of leguminous plants, on the tubercles on the, with special reference to the pea and bean (Ward), 431. Roux (H.) les inoculations préventives. —Croonian lecture, 154. Russell (W. H. L.) on certain geome- trical theorems. No. 4, 376. Sandstone, barium sulphate as a cement in (Clowes), 363. Saturn and Uranus, note on the photo- graphic spectra of (Huggins and Huggins), 231. Schuckburgh’s (Sir George) scale, com- parison of, with French standard métre, 454. Sea-water, on the velocity of transmis- sion through, of disturbances of large amplitude caused by explosions (Threlfall and Adair), 496. Selenic acid and other selenium com- pounds, researches in the chemistry of (Cameron and Macallan), 13. Shipley (A. E.) on Phymosoma varians, 122. Silurian rocks near New Galloway, effects of contact metamorphism ex- hibited by the (Allport and Bonney), 193. Siluride, the air-bladder and Weberian ossicles in the (Bridge and Haddon), 309. g 2 liv INDEX. Sine law of Malus, an experimental verification of the (Spitta), 376. Skatole in the vegetable kingdom, on the occurrence of (Dunstan), 211. Smith (F.) the chemistry of the urine of the horse, 328. Solar and stellar light in the ultra- violet part of the spectrum, on the limit of (Huggins), 133. Physics Committee, further dis- cussion of the sun-spot observations made at South Kensington, a report to the (Lockyer), 385. Sollas (William Johnson) elected, 175. admitted, 253. Spark discharge, observations on the (Joly), 376. Specific inductive capacity of a dielec- tric, on the effect of temperature on the (Cassie), 357. inductive capacity of dielectrics when acted on by very rapidly alter- nating electric forces (Thomson), 292. resistance and other properties of sulphur (Monckman), 1386. Spectra of oxygen, and some of its compounds, notes on the absorption (Liveing and Dewar), 222. of Uranus and Saturn, note on the photographic (Huggins and Hug- gins), 231. : Spectrum, on the limit of solar and stellar light in the ultra-violet part of the (Huggins), 133. — of manganese, on the wave-length | of the chief fluting seen in the (Lockyer), 35. visible and photographic, of the great nebula in Orion, on the (Hug- gins and Huggins), 40. Spitta (EH. J.) an experimental verifica- tion of the sine law of Malus, 376. Stellar and solar light in the ultra- violet part of the spectrum, on the limit of (Huggins), 133. Stewart (Balfour) obituary notice of, ix. Storage batteries, contributions to the chemistry of. No. 2 (Frankland), 304. Sulphur, the specific resistance and other properties of (Monckman), 136. Sun-spot observations made at South Kensington, further discussion of the. A report to the Solar Physics Com- mittee (Lockyer), 385. Tanakadate (A.) and J. T. Bottomley, note on the thermo-electric position of platinoid, 286. Terrestrial magnetism, on a possible geological origin of (Hull), 92. Thermo-electric position of platinoid, note on the (Bottomley and Tanaka- date), 286. Thomas (O.) on the dentition of Orni- thorhynchus, 126. Thompson (C.) and C. R. A. Wright, note on the development of voltaic electricity by atmospheric oxidation of combustible gases and other sub- stances, 372. Thomson (J. J.) note on the effect produced by conductors in the neigh- bourhood of a wire onthe rate of pro- pagation of electrical disturbances along it, with a determination of this rate, 1. specific inductive capacity of di- electrics when acted on by very rapidly alternating electric forces, 292. Threlfall (R.) and J. F. Adair, on the velocity of transmission through sea- water of disturbances of large ampli- tude caused by explosions, 496. Time-lag in the magnetisation of iron, on (Ewing), 269. Todd (Charles) elected, 175. Tomlinson (Herbert) elected, 175. admitted, 253. Toxic action of the albumose from the seeds of Abrus precatorius (Martin), 100. Trimen (Henry) admitted, 175. Trimen (Roland) admitted, 384. Trust funds, 464. Tubercles on the roots of leguminous plants, with special reference to the pea and bean, on the (Ward), 431. Uranus and Saturn, note on the photo- graphic spectra of (Huggins and Huggins), 231. Urine of the horse, the chemistry of the (Smith), 328. Vaporised metals, on films produced by, and their applications to chemical analysis (Hartley), 88. Variability in condensing swarms of meteorites, on the cause of (Lockyer), 401. Variables, on the interchange of the, in certain linear differential operators (Elliott), 358. Variations of Cardium edule, apparently correlated to the conditions of life, on some (Bateson), 204. Veley (V. H.) the conditions of the re- action between copper and nitric acid, 216. : ® > a INDEX. lv Voltaic balance, determining — the strength of liquids by means of the (Gore), $7. electricity, note on the develop- ment of, by atmospheric oxidation of combustible gases and other sub- stances (Wright and Thompson), 372. Vuleanised india-rubber, physical pro- perties of (Mallock), 233. Ward (A. W.) on the magnetic rotation of the plane of polarisation of light in doubly refracting bodies, 65. Ward (H. M.) on the tubercles on the roots of leguminous plants, with special reference to the pea and bean, 431. Water, velocity of transmission of dis- turbances in. See Sea-water. Ware-length of the chief fluting seen in the spectrum of manganese, on the (Lockyer), 35. Weberian ossicles in the Siluride, the air-bladder and (Bridge and Haddon), 309. Weldon (Walter) obituary notice of, 5b. o8 Williams (Charles James obituary notice of, xxvi. Woltenden (R. N.) and 8. Martin, phy- siological action of the active principle of the seeds of Abrus precatorius (jequirity), 94. Worms (Baron Henry de) admitted, 65. Wright (C. R. A.) and ©. Thompson, note on the development of voltaic electricity by atmospheric oxidation of combustible gases and other sub- stances, 372. Blasius) Yeo (Gerald F.) elected, 175. admitted, 253. Zirconium and its atomic (Bailey), 74. weight ERRATA. Page 211, line 14 from bottom, for “ 1887” read “ 1877.” a9 212 23 21 33 3? 449 3) 3 », “phenylhydrazide” read “ pbenylhydrazone.” 5, ‘With one exception the senior of our” read ** one of our senior,” END OF FORTY-SIXTH YOLUME. HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN’S LANE. PROCEEDINGS OF | i | THE ROYAL SOCIETY. ae VOR MLVI. . ae | No. 280. S19 LI 1h he CONTENTS. | é May 2, 1889. el | PAGE I. Note on the Effect produced by Conductors in the Neighbourhood of a Wire on the Rate of Propagation of Electrical Disturbances along it, ig pe with a Determination of this Rate. By J. J. THomson, M.A., F.RS., Be’ | Cavendish Professor of Experimental Physics, Cambridge oe t eee II. Researches in the Chemistry of Selenic Acid and other Selenium Com- pounds. By Sir Cuarnes A. Cameron, M.D., F.R.C.S.1., V.P.LC., Professor of Chemistry and Hygiene, R.C.S.1., and JOHN Macannan, F.1.C., Demonstrator of Chemistry, R.C.S.I. : : : . ora III. On the Wave-length of the chief Fluting seen in the Spectrum of Manga- nese. By J. Nonman Lockyer, F.R.S. Gina ee is ee eos. IY. The Accurate Determination of Carbonic Acid and Moisture in Air. By an J. 8. Hatpang, M.A., M.B., and M.S. Pemprey, Pell Exhibitioner of - el Christ Church, Oxford. (From the Physiological Laboratory, Oxford). 40 3 V. On the Spectrum, Visible and Photographic, of the Great Nebula in ce eo. i Orion. By Wittiam Hveerns, D.C.L., LL.D., F.R.S., and Mrs. : Hueeins (Platel) . . : : Lear oe Oe AO ae q List of Presents . ; ee : : : Mees : : OLE tame May 9, 1889. I. On the Magnetic Rotation of the Plane of Polarisation of a in sou Ce refracting Bodies. By A.W. Warp . : : : 65° eS ‘" II. Revision of the Atomic Weight of Gold. By J. W. Mater, F.RS. ae ' _ Professor of Chemistry i in the University of Virginia . : ; ee ‘ee IIL. Zirconium and its Atomic ae By G. H. Barzey, D.Sc., Ph.D., The i Owens College. : é : : : : : : Ai as IV. Magnetic and other Physical ee of Iron at a High ee : | By Jonny Horxinson, F.B.S. ; : : : ; : 5 <) See : VY. Determining the Strength of oe by means of the Voltaic Balance. | eo By G. Gort, LL.D., F.RS. ‘ : : : : : ~72 80, ee _ VI. On Films produced by te ea Metals and their Applications to os Chemical Analysis.— Preliminary Notice. hs N. ote E.R.S., Royal College of Science, Dublin . : : : : - 88s List of Presents . eat ; : : ; : : ; wh eee OO : For continuation of Contents see 2nd page of Wrapper. : Sues a Price Siz Shillings and Sixpence. CONTENTS (continued). Reeve) May 16, 1889. oe fa Heel elon. I. On a possible Geological Origin of Terrestrial Magnetism. By : Epwarp Hurt, M.A., LL.D., F.B.S., Director of the Geological ae Survey of Ireland . 92 ag II. Physiological Action of the Aces Panorgls he the iSeede of sores precatorius (Jequirity). By Stpney Martin, M.D. London, British - Medical Association Research Scholar, Assistant Physician to the Victoria Park Chest Hospital, and R. Norris WonFenpDEN, M.D. (Cantab.). (From the Physiological Laboratory, University College.) 94 TIT. The Toxic Action of the Albumose from the Seeds of Abrus preca- torius. By Stpney Martin, M.D. London, British Medical Associa- tion Research Scholar, Assistant Physician to the Victoria Park Chest Hospital. (From the Physiological es University College, London.) . : 100 TV. On the early Dey iopuient a Lepaosons OSSCUS. Prétaaeies Nous By J. BEARD, Ph.D., B.Sc., Zoologist to the Scottish Fishery Board, Edinburgh ; : + COS V. The Assimilation of Carbon by isch Plants fin cen Oran Compounds. By E. Hamitron Acton, M.A., Fellow of St. John’s 4 College, Cambridge . : Re ices VI. Appendix to Paper on leeendiay Dee econ follow ‘Tenese in the Gyrus date? and Gyrus fornicatus in Monkeys. By E. P. FRANCE . : - : : 4 j : ; on eee VIL. On Phymosoma varians. By ArtHuR KE. Surpiey, M.A., Fellow and Lecturer of Christ’s College, Cambridge, and Demonstrator of Com- parative Anatomy in the University . : 122 VIII. On the Dentition of Ornithorhynchus. 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Boys, ARS Mw RS, _ Assistant Professor of Physics at the Normal School of Science, South — Kensington ‘ ducele tb heap : : : ; : pas a IL On Time-lag in the Magnetisation of Iron. By J. A. Ewrna, B. ee oe ESR. S., Professor of Engineering in University College, Dundee a, Note on the Thermo-electric Position of Platinoid. By J. nis Borromiey, M.A., FR. S., and A. TANAKADATE, Rigakusi ete +1, ‘Specific Inductive Capacity of Dielectrics when acted on by very " rapidly alternating Electric Forces. Do aed eee THomson, M. A. af #&F a 8., oe Professor of Physics, Cambridge . : we, Contributions to the Chemistry of Storage Epiitonies YN Of Zt By Rea FRaNKLAnD, D.C.L., FBS. ans : : ‘ i : vi. Contributions to the Anatomy of Fishes. I. The Air-bladder and ~~ ‘Weberian Ossicles in the Siluride. By T. W. Brine, M.A., Proce fessor of Zoology in the Mason College, Birmingham, and A. C. : -Happoy, M.A., Professor of Zoology im the oe College of oe Dublin 5 ‘ 3 . ° . 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