Dec. 23, iSSoJ 



NATURE 



187 



Botany : Hillhouse, Trinity, and Hoffmeister, Caius (distin- 

 guished) ; and three for Zoology, Anatomy, and Physiology : 

 Caldwell, Caius ; Pigeon, Christ's ; and Shaw, Sidney. 



Mr. J. A. Fleming, B.A., of St. John's, has been appointed 

 to the new post of Demonstrator of Mechanism and Applied 

 Mechanics ; Mr. Fleming is a distinguished graduate of London 

 Univen-ity, as well as having attained distinction in Physics, 

 with first class honours in the Natural Science Tripos of this 

 year. 



Mr. J. J. Lister, B.A., of St. John's College, has been 

 appointed Demonstrator of Comparative Anatomy, in place of 

 Mr. A. C. Haddon, who has been appointed to the Professor- 

 ship of Zoology and Comparative Anatomy in the Royal College 

 of Science, Dublin, vacated by Prof. Bridge. 



Mr. A. H, Cooke, B.A., Fellow of King's College, has been 

 appointed Curator of the Zoological Museum. 



SCIENTIFIC SERIALS 

 Aniiakn der Physik mzd Chcmie, No. 11. — Magnetic re- 

 searches, by F. jVuerbach. — New researches on magnetism, by 

 C. Baur. — On so-called polar induction, by E. Riecke. — Deter- 

 mination of the absolute velocity of cm'rent electricity from 

 Hall's phenomenon, by A. v. Ettingshausen • — Method of 

 calibration of a wire for galvanic measurements, by W. Giese. 

 — Action of gases and vapours on the optical properties of re- 

 flecting surfaces, by P. Glan. — On a new interference-photo- 

 meter, byiFr. Fuchs. — Influence of the density of gases on their 

 conduction of heat, by A. Winkelmann. — Currents of liquids 

 resulting from unequal temperature within them, by A. Oberbeck. 

 — Theory of the interference-phenomenon presented by dichroitic 

 crystal-plates cut at right angles to the axis, \yj E. Ketleler. — 

 On the polarisation of diffracted light, by M. Rethy. — On 

 changes produced in the spark and brush phenomena by coverings 

 of the electrodes, by W. Holtz. — On atmospheric refraction of 

 sound rays, by A. Kneser. — Double-acting mercury-pump with- 

 out cock, by F. Neesen. — Alteration of Rvidorffs absorption- 

 hydrometer, by the same. — Reply to a note by O. E. Meyer, by 

 L. Eoltzmann. — Remarks on U. Duhring's paper on the law of 

 corresponding boiling temperatures, by A. Winkelmann. 



SOCIETIES AND ACADEMIES 

 London 



Zoological Society, December 14. — Prof. W. i\. Fowler, 

 LL.D., F.R.S., president, in the chair. — Mr. Sclater exhibited 

 and made remarks on a skin of a brown female of I'au.xis galeata, 

 formerly living in the aviary of the late Mr. G. Dawson Rowley, 

 F.Z.S. — Dr. A. Glinther, F.R.S., exhibited and made remarks 

 on a skin of a new species of Rhynchoryon from Eastern Africa, 

 discovered by Dr. Kirk. — Prof. T. H. Huxley, F.K.S., read a 

 paper on the application of the laws of evolution to the arrange- 

 ment of the Vertebrata, and more particularly of the Mammalia. 

 — Lieut. -Col. PL H. Godwin-Austen, F.R.S., read a paper on 

 the anatomy of Ferussacia gronoviana, Ri^so, from Mentone, 

 pointing out its general relationship with Lovea tontatdlina, 

 Lowe, of Madeira, and with Fey-ussacia foUicida, Gronov., from 

 Algiers. — Mr. Arthur G. Butler read a paper on a second col- 

 lection of Lepidoptera made in Formosa by Mr. PL E. Hobson. 

 Thirty-three new species were found in this collection. — Mr. 

 Oldfield Thomas, F.Z.S., read a paper containing the descrip- 

 tion of a new species of Reithrodon, obtained in Venezuela by 

 the late Mr. D. Dyson, which was described as Reithrodon 

 alstoni. — Dr. A. GUnther read a paper containing notes on some 

 rare reptiles and batrachians now or lately living in the Society's 

 Gardens. 



Physical Society, December 11. — Prof. W. G. Adams in 

 the chair.— New Members : Mr. W. R. Brown, Mr. T. Might- 

 son, C.E. — Lieut. L. Darwin read a paper on the rate of loss 

 of light from phosphorescent substances. His experiments were 

 made at Chatham on Balmain's luminous paint, by comparing 

 the intensity of the phosphorescent light with the light of a 

 sun-burner ; the luminous surface being kept cool by placing 

 ice and water near, as a slight increase of temperature in the 

 surface considerably increases the quantity of light given off in 

 a certain space of time. The supply of light was communicated 

 to the paint from a mirror reflecting sunlight. A table and a 

 curve exhibited to the meeting showed the rate of loss found by 

 Lieut. Darwin. It is independent of the original intensity of 

 of the illumination. According to the curve the light diminishes 



very nearly in proportion to the square of the intensity of the 

 light. In a report on the use of Balmain's paint in mines, it 

 had been stated that the phosphorescence became brighter a few 

 minutes after expo-ure in the dark ; but the curve showed this 

 to be an error, due probably to the fact that the eye becomes 

 more sensitive to light after being a few minutes in the dark. 

 Mr. Pearsall emphasised the advantages of such a light in fiery 

 mines. Prof. Gulhrie inquired if the phosphorescent power 

 grew weaker by time, and Lieut. Darwin instanced a specimen 

 eighty years old to the contrary ; but Dr. \V. Crookes stated that 

 these luminous substances give off sulphuretted hydrogen in damp 

 air and deteriorate. If sealed in a vacuum they would not. Dr. 

 Crookes remarked that in Balmain's patent it was stated that the 

 phosphorescence died out sooner when exposed to a strong light 

 for a short time than to a weak light for a Linger time ; bnt Lieut. 

 Darwin thought this was explained by the slow decrease in the 

 lower part of the ciuwe when the phosphore-cenee became faint. 

 Mr. R. J. Lecky mentioned that Evelyn in his Diary (1650) 

 describes a phosphorescent powder as "bottling up" sunlight. 

 Dr, Coffin inquired if short exposure to strong light was equiva- 

 lent to long exposure to feeble light. Lieut. Darwin thought 

 not. — Dr. C. R. Alder Wright read^a full paper on the deter- 

 mination of chemical affinity in terms of electromotive force. 

 He considered first the value of the B. A. unit of resistance, 

 which from different experimenters might be taken as really 

 I '005 earth quadrants per second, or not more than half per cent, 

 out. Clark's element when carefully prepared was practically 

 correct at I '457 volts, and it kept constant for three or four 

 months after being made, but deteriorated thenceforth some 3 

 per cent, in about two years. The deterioration was assisted by 

 air, which could not be well excluded by the paraffin cork, as it 

 cracked. If sealed in a Sprengel vacuum the element lasted 

 better. Joule's mechanical equivalent of heat ( /) he estimated 

 at 42 X 10", or not over i per cent, greater than Joule's water 

 value. The chief result of Dr. Wright's researches was the 

 conclusion that the action of a current in electrolysis is to 

 decompose the electrolyte into " nascent " products which evolve 

 heat in changing into ordinary products of electrolysis. These 

 na.'cent products may be the ultimate atoms composing the 

 molecules of the ordinary products, and the heat is given 

 out in these atoms coming together to produce molecules, 

 say of oxygen and hydrogen in the case of winter. A 

 number of deductions from this theorem are verified by experi- 

 ment. One of these is that no gas batteiy can give a higher 

 E.M.F. than i'5 volts. A result, not before published, is 

 that the E.M.F. of a Daniell cell is a function of the current 

 and is a maximum when the current is indefinitely small. The 

 variation may amount to 10 degrees. Therefore all methods of 

 determining resistance by means of two currents of different 

 strength are inaccurate. Dr. Wright's experiments also verified 

 Faraday's law that conduction in an electrolyte is always accom- 

 panied by electrolysis. Prof. Adams inquired if Dr. Wright 

 had seen the letter of Prof Rowland's assistant to the effect that 

 Dr. Wright's former estimate of the ohm was on the WTong side 

 of unity. He had been too busy to see it. Prof Foster thought 

 that the variation of E.M.F. in a cell with the current was to be 

 expected, and was probably due to the slowness of diffusion. Dr. 

 Wright thought diffusion woidd account for it. Dr. Lodge 

 said that there was no way of measuring the resistance of a cell 

 except by employing two currents of different strength, and 

 therefore it was necessary to know the law of variation of 

 E.M.F. with current strength. Dr. Wright stated that he had 

 found two methods of proceeding with currents of the same 

 strength. With regard to the deduction of Dr. Wright that no 

 current passes without producing electrolysis, Mr. Walenn in- 

 quired if the ordinary law of solution held when there was no evolu- 

 tion of hydrogen, and was answered in the affirmative. — Prof. 

 Guthrie cited the experiments of Mr. C. V. Boys and himself on the 

 conductivity of liquids as an instance of a current passing with- 

 out electrolysis, or if there was decomposition it was followed 

 by instant recomposition. Dr. Wright thought there must be 

 electrolysis in Dr. Guthrie's experiments (which were conducted 

 by rotating a glass vessel filled with the liquid between the 

 poles of a magnet, after Arago's experiment), because some two 

 parts of the rotating vessel would be at different potentials, and 

 a current would be set up in the liquid. — The Society then 

 adjourned till after Christmas. 



Paris 



Academy of Sciences, December 13. — M. Edm. Becquerel 



in the chair. — The following papers were read:— Solid and 



