iMay 19, 1892] 



NATURE 



71 



—The Hon. Walter Rothschild communicated a paper entitled 

 " Notes on a collection of Lepidoptera made by Mr. William 

 Doherty in Southern Celebes during August and September, 

 1891." He also sent for examination the types of the new 

 species described therein. — Dr. Sharp read a paper entitled 

 " On the eggs of an Hemipterous Insect of the family Reduviida. 

 Mr. McLachlan, F.R.S., Mr. Poulton, F. R. S. , and Mr. Hamp- 

 son made some remarks on the subject. 



Matheniatical Society, May 12.— Prof. Greenhill, F.R.S., 

 President, in the chair. — The following communications were 

 made : — A Newtonian fragment on centripetal forces, by Mr. 

 W. W. Rouse Ball. The demonstrations given by Newton in 

 his •' Principia" are geometrical, though there is little doubt 

 that in establishing the truth of some of his results he used 

 fluxions (cf. the " Commercium Epistolium," Rigaud's "Essay 

 on the first publication of the 'Principia,'" and Brewster's 

 "Life of Newton"). To his contemporaries the language and 

 methods of geometry were familiar, while to most of them the 

 calculus was unknown ; hence it was natural and reasonable that 

 the proofs should be presented in a geometrical form. It is 

 probable that the fluxional analysis by which a result was 

 obtained was generally thrown aside as soon as a synthetic 

 geometrical proof had been found ; apparently the only propo- 

 sition in the book of which Newton's fluxional demonstration 

 has been published is his determination of the form of the solid 

 of least resistance, of which the result alone was given in Book 

 ii., Scholium to Prop. 35 (first edition). Among the numerous 

 sheets of rough work and calculations which are preserved in 

 the Portsmouth collection is a fragment on the law of centri- 

 petal force under which any orbit, and |>articularly a parabola 

 of any order, can be described. The theorem to which the 

 analysis leads is so inconvenient of application as to be practic- 

 ally useless, and probably for that reason was not inserted in 

 the "Principia." Such interest as it possesses lies rather in 

 its illustrating the way in which Newton arrived at the law 

 given (in the paper) for the description of any parabola under a 

 central force. The date of the fragment is put "about the 

 year 1694," when we know that Newton was engaged in revising 

 the first edition of the "Principia." — On an operator that pro- 

 duces all the covariants and invariants of any system of 

 quantics, by Dr. :W. E. Story.— Applications of a theory of 

 permutations in circular procession to the theory of numbers, 

 by Major MacMahon, F.R.S. 



Oxford. 



University Junior Scientific Club, March 18. — Mr. J. 

 A. Gardner, Magdalen College, President, in the chair. — A 

 paper was read by Mr. J. E. Marsh, Balliol College, on varia- 

 tions in the rotatory power of turpentine oil. This was chiefly 

 given up to the consideration of the probable explanation of 

 the phenomenon. The experiments were described at length in 

 the Journal of the Chemical Society some months back. — Mr. 

 T. H. Butler, of Corpus Christi College, read a paper on poisons, 

 chiefly in relation to their physiological action. — Mr. H. Balfour, 

 of Trinity College, exhibited a whaling cross-bow from Green- 

 land.— Mr. F. Britten, of Christ Church, exhibited a specimen 

 of incrustation. 



March 30. — Mr. J. A. Gardner, President, in the chair. — 

 Mr. E. B. Poulton, F. R. S., reada paper on a further investi- 

 gation of the degenerate scales of Lepidoptera with trans- 

 parent wings, which was illustrated by the magic lantern. — Mr. 

 O. V. Darbishire, Balliol College, read a note on karyokinesis, 

 illustrated by microscopical preparations. — A note was read by 

 Mr, R. S. Hughes, 'Jesus College, on the action of dried 

 hydrogen sulphide on magnesia, 



Dublin. 



Royal Dublin Society, April20.— Sir Robert Ball, F.R.S., 

 in the chair.— The following communications were made :— 

 On a new mercury-glycerine barometer, by Dr. J. Joly. This 

 barometer has the full range of the glycerine barometer. The 

 total length of the tube is, however, only 250 cms, about. 

 This result is attained by weighting the glycerine in the tube by 

 a column of mercury 67 cms, in length. By means of a 

 float in the mercury which pulls a disk, loosely fitting the tube, 

 against the base of the column, this is kept from breaking, and 

 falling down through the glycerine. In a uniform tube this 

 column remains of invariable length and moves up and down 



with the glycerine. The balance of the atmospheric pressure 

 is equilibrated by glycerine drawn from a bath of glycerine. 

 Owing to the short length of tubing traversed by the viscous 

 liquid, the instrument is probably more prompt than the full 

 length glycerine barometer. On the other hand, there appears 

 to be a very slow ascent of the glycerine past the mercury, which 

 will probably necessitate the resetting of the instrument at 

 intervals. — Mr. J. R. Wigham read a paper explanatory of the 

 nevir "giant" lighthouse lens, the largest ever made, which he 

 exhibited to the meeting. It was constructed for him by Messrs, 

 Barbierand Co., of Pans. Its focal distance is 2 metres, and its 

 axial intensity equal to 800,000 candles. The beam which this 

 lens, in triform, in conjunction with Mr. Wigham's new 

 "intensity" burner, is capable of transmitting to the mariner, 

 has more than five times the power of that of Tory Island, the 

 largest lighthouse light in the world, and is much more effica- 

 cious in penetrating fog than the most powerful electric light. 

 —Dr. G. Johnstone Stoney, P'.R.S., read a paper on the 

 cause of the absence of hydro^jen from the earth's atmo- 

 sphere, and of water and air from the moon. In this com- 

 munication reference is made to the conditions that determine- 

 the height of an atmosphere upon any celestial body. These 

 had been announced by the author in a paper "On the Phy- 

 sical Constitution of the Sun and Stars," printed in the Pro- 

 ceedings of the Royal Society for 1868 ; and in the present 

 paper it is pointed out that the same method of investigation 

 shows that under certain circumstances some of the constituents 

 of an atmosphere may, molecule by molecule, wander off" inta 

 space. This event occurs with more readiness — (i) the lower 

 the mass of the molecules of the gas ; (2) the feebler the attrac- 

 tion downwards at the boundary of the atmosphere ; (3) the 

 higher the temperature at the boundary of the atmosphere. ^^ 

 investigating the conditions that prevail on the earth and 

 moon, it is shown that free hydrogen could not remain 

 a constituent of the earth's atmosphere ; and that no 

 free oxygen, nitrogen, or the vapour of water, could remain on 

 the moon. Hence, even if there were no oxygen present, the 

 earth's atmosphere could not retain free hydrogen ; and on the 

 moon there is now neither atmosphere, such as we know it, nor 

 water, nor ice. It follows from the investigation that space 

 must be peopled with vast numbers of wandering gaseous 

 molecules, especially of the lighter gases, and that these tend 

 ultimately to settle down upon such of the more massive bodies 

 of the universe as are sufficiently dense to exercise a powerful 

 attraction at their surface. Finally, the investigation indicates 

 conditions which must be fulfilled by any " nebular hypothesis" 

 in order that it may be admissible. — A list of Irish Rotifers, 

 with descriptions of twenty-five new species, by Miss Glascott, 

 was communicated by Prof. A, C. Haddon. 



Paris. 



Academy of Sciences, May 9. — M. d'Abbadie in the 

 chair. — Photographs of solar prominences taken by M. Des- 

 landres at Paris Observatory, by M, Mouchez. This is a brief 

 statement of the work that is being done at Paris on the 

 dimensions and velocities of solar prominences. By the methods 

 employed the radial velocity can be determined within about a 

 kilometre per second. Some of the photographs obtained were 

 presented by M. I'Amiral Mouchez to the Academy. It is pro- 

 posed to make a continuous record of the movements of the solar 

 atmosphere as soon as the necessary funds are obtained. — On the 

 propagation of Hertz oscillations, by M. H. Poincare. — On resi- 

 dual life and the products of the action of separate tissues of living 

 beings, by MM. A. Gautier and L. Landi. After a healthy animal 

 has been killed, a considerable interval elapses before the death of 

 the tissues. This action after the death of the body as a whole 

 is termed • ' la vie residuelU " by the authors. They have investi- 

 gated the changes that go on by analyzing flesh freshly killed 

 and otherwise, and comparing the results. — On entire functions 

 of the form e'^M ^ by M. Hadamard. — A theorem on harmonic 

 functions, by M. G. D. d'Arone.— On the determination of the 

 moment of the torsion couple of a unifilar suspension, by M. C. 

 Limb, — Action of potassium cyanide on ammoniacal copper 

 chloride, by M. E. Fleurent, By heating together in sealed 

 tubes potassium cyanide, cupric chloride, and ammonium 

 chloride, the author has succeeded in forming the compound?,, 

 (i) 2Cu2Cy2 , AmCy . 2NH3 , SU^O, forming long blue needles, 

 very unstable ; (2) aCuCyj. CujCyj, 2NH3. 3H2O, green rect- 

 angular plates, quite stable in the air.— Sodium trimethylcarbinol : 



NO. II 77, VOL. 46] 



