358 



NA TURE 



{Feb. II, i! 



tion of zinc sulphate and a little zinc carbonate. A stock of 

 paste may be prepared and retained for use in a bottle. 



Experiments are described tending to prove that the irregu- 

 larities observed during the first few weeks of the life of a cell 

 prepared with acid materials have their origin principally at the 

 mercury electrode. 



Cells prepared with dilute solutions have a lower temperature 

 coefficient (about o '00038), but would be more difficult to use as 

 standards whose value is to be inferred from the mode of 

 preparation. 



Details are given of H-cells charged with amalgams of zinc 

 and mercury in both legs, without mercurous sulphate. .V 

 very small proportion of zinc is sufficient to produce the 

 maximum effect. Pure mercury, neither alloyed with zinc nor 

 in contact with mercurous sulphate, has an uncertain electro- 

 motive value. 



Since the comparison of cells does not absolutely exclude a 

 small general alteration of electromotive force with age, further 

 determinations of the standard cell (No. i) have been effected 

 by means of the silver voltameter. The results — 

 Table XVIII. 



Cite E.M.F.ofNo lat.soC. 



in B..\. volts. 



October 1883 to April 1884 I'4542 



November 1884 i'4540 



August 1885 1-4537 



are very satisfactoiy, and indicate a constancy sufficient for 

 almost all practical purposes. 



Finally, some comparisons are given between Clark cells and 

 Daniells, with equi-dense solutions, both of Raoult's pattern and 

 of that described recently by Dr. Fleming. 



Entomological Society, January 20. — Fifty-third Anni- 

 versary Meeting.— Mr. R. McLachlan, F.R.S., President, in 

 the chair. — An abstract of the Treasurer's accounts was read by 

 Mr. H. T. Stainton, F.R.S., one of the auditors, and the 

 Secretary read the report of the Council. — The following 

 gentlemen were then elected as the Council for 18S6 : — Pre- 

 sident : Robert McLachlan, F.R.S. ; Treasurer: Edward 

 Saunders, F.L.S. ; Secretaries: Herbert Goss, F.L.S., and 

 the Rev. W. W. Fowler, M.A., F.L.S. ; Librarian : Ferdinand 

 Grut, F. L. S. ; other Members of Council : T. R. Billups, 

 Edward A. Fitch, F.L.S., F. Du Cane Godman, M.A., 

 F.R.S., W. F. Kirby, E. B. Poulton, M.A., F.G.S., H. T. 

 Stainton, F.R.S., S. Stevens, F.L.S., and J. Jenner Weir, 

 F.L.S. — The President then delivered an address, and a vote of 

 thanks to him was moved by Mr. Stainton, and seconded by 

 Mr. F. Pascoe, and the President then replied. A vote of 

 thanks to the officers was then moved by Mr. J. W. Dunning, 

 and seconded by Mr. Distant, and Messrs. Saunders, Fitch, 

 Kirby, and Grut replied. This was the first annual meeting 

 since the incorporation of the Society by Royal Charter. 



Zoological Society, February 2.— Prof. W. H.TTower, 

 V.P.R.S., President, in the chair.— Mr. W. B. Tegetmeier, 

 F.Z. S., exhibited and made remarks on a Pheas.ant from the 

 Persian borders of Transcaucasia. — Mr. C. A. Wright, F.Z.S., 

 exhibited a Dove of the genus Turtur from Malta, and identified 

 it as a semi-albino variety of Tiirtur auritiis. — Mr. Sclater 

 exhibited, on behalf of Mr. W. H. Dobie, a young specimen of 

 Sabine's Gull {Xaiia sacn'in'i), which had been obtained at 

 Mostyu, on the coast of Flintshire. — Mr. Seebohm exhibited a 

 specimen of Ross's Sea-Gull (Larus rossi) obtained in June last 

 in the neighbourhood of Christianhaab, Disco Bay, Greenland. 

 — Capt. R. G. Wardlaw Ramsay exhibited and remarked on a 

 specimen of a new bird of the genus Copsychus obtained by Mr. 

 H. Pryer in North-Eastern Borneo, which he proposed lo call 

 C. ni^t-r. —A communication was read from Prof. R. Collett, 

 C.M.Z.S., containing an account of the external characters of 

 the Northern Fin-Whale [Balicnoptcra horcalis], based upon the 

 examination of numerous specimens of this whale killed on the 

 coast of Norway during the past summer. — A communication 

 was read from Dr. G. Stewardson Brady, F.R.S., containing 

 descriptions of some new freshwater Entomostracous Crustaceans 

 from South Austraha. — Dr. H. Woodward, F.Z.S., communi- 

 cated, on behalf of Dr. Monticelli, a catalogue of the species of 

 Bats found in South Italy.— Mr. R. B. Sharpe, F.Z.S., read 

 the first of a series of notes on birds in the Hume Collection. 

 The present communication treated of the specimens supposed 

 to belong to the Hawfinch of Europe, which had been collected 

 at Attock, and showed that they belong to a different species, 

 which Mr. Sharpe proposed to call Coccothraustes /lumii.—Mx. 



F. E. Beddard read the third of his series of notes on the Iso- 

 poda collected during the voyage of H.M.S. C/iallens^er. The 

 present paper completed the preliminary description of the new 

 species of this group collected during the voyage, which 

 amounted altogether to about forty-five in number. — Mr. J. H. 

 Leech, F.Z.S., exhibited and described specimens of a Butterfly 

 from Mogador, which he referred to a tvariety of Anthocharis 

 eupheno. 



Geological Society, January 27.— Prof. T. G. Bonney, 

 F.R.S. , President, in the chair. — H. Kirby Atkinson was 

 elected a Fellow, and Prof. Gustav Tschermak, of Vienna, a 

 Foreign Member of the Society.— The following communica- 

 tions were read : — On the fossil Mammalia of Maragha, in 

 North-Western Persia, by R. Lydekker, F.G.S.— On the Plio- 

 cene of Maragha, Persia, and its resemblance to that of Pikermi, 

 in Greece ; on fossil elephant-remains of Caucasia and Persia ; 

 and on the results of a monograph of the fossil elephants of 

 Germany and Italy, by Dr. H. Pohlig. Communicated by Dr. 



G. J. Hinde, F.G..S. — The Thames Valley surface-deposits of 

 the Ealing district and their associated Palaeothic floors, by John 

 Allen Brown. Communicated by A. Ramsay, F. G.S. 



Victoria (Philosophical) Institute, January iS. — Rev. 

 Dr. Thornton in the chair. — -A. paper upon " A Sanioan Tradi- 

 tion of Creation and the Deluge " was read by the Rev. T. 

 Powell, F.L.S. Mr. Powell said he thought the Samoans were 

 of Semitic origin ; and if Hebrew characters had been used 

 instead of the Roman alphabet for the writing of their language, 

 the triliteral, Semitic nature of the language, in which hundreds 

 of words were identical with Hebrew, would have been obvious. 

 Manchester 



Literary and Philosophical Society, November 3, 1885. 

 — Prof W. C. Williamson, LL.D., F.R.S,, President, in 

 the chair. — On the different arrangements in a state of maxi- 

 mum density of equal spherical granules, by R. F. Gwyther, 

 M.A. — Note on the velocity with which air rushes into a 

 vacuum, and on some phenomena attending the discharge 

 of atmospheres of higher, into atmospheres of lower, density, 

 by Mr. Henry Wilde. .Since the reading of my paper before 

 the Society on the efflux of air, I have thought that it might be 

 useful to recapitulate, briefly, the fundamental grounds upon 

 which my experiments and the general reasoning thereon were 

 based. This appears to me to be further necessary, from the 

 dual sense in which the term " velocity" may be considered in 

 the discharge of elastic fluids : the term, as I have already 

 pointed out, has been applied by some, indifferently, to express 

 the rate of increase of volume after leaving the aperture, and 

 the velocity of the stream through the aperture before expansion. 

 It is in the latter sense that the term is used in my paper, and 

 the velocities shown in the several tables have been calculated on 

 this basis. The application of the laws of discharge of inelastic 

 fluids to those which are elastic is a natural principle of reason- 

 ing sufficient for us to assume a theoretic velocity for air rushing 

 into a vacuum of 1332 feet per second ; and the coroUary to this 

 proposition, that the velocity of efflux through the aperture into 

 a vacuum is the same for all pressures above and below that of 

 the atmosphere also follows, naturally and directly, from the 

 reciprocal relations of the elasticity and density of the homo- 

 geneous atmosphere. But, just as the theoretic velocity of dis- 

 charge of water and other inelastic fluids is diminished by the 

 opposing motions and friction of the issuing stream of particles, 

 so that the amount of discharge is only '62 of that required by 

 theory ; so from the varied mobility of different gases there was 

 an antecedent probability that an ideal law would not prevail 

 for the velocity with which air has been assumed to flow into a 

 vacuum. Hence, just as the hydraulic coefficient '62, express- 

 ing the actual amount of efflux through a hole in a thin plate, 

 could only be arrived at by experiment ; so by experiment only 

 could the actual velocity with which the atmosphere rushes into 

 a vacuum be ascertained. This velocity, therefore, as deter- 

 mined by experiment, may be represented by the coefficient 77 

 for the contracted vein. Or, V = 77 x 1332 = 1025 feet per 

 second. From Tables I. and II. itappears that the corollary of the 

 equality of the velocities for all pressures, when air flows into a 

 vacuum, is not strictly applicable for the lower pressures, but is 

 approximately true for pressures above 120 lbs. That air of 

 lower density acts as a vacuum to the discharge into it of air of 

 higher density, under certain conditions, is a truth so well 

 established from the experiments described as to require no 

 further proof, but, that the reduction of temperature at the 

 orifice of the discharging vessel did not sensibly affect the velo- 



