December 19, 1907] 



NA TURE 



167 



Cambridge. 

 Philosophical Society, Uciober 2?. — Dr. Hobson, presi- 

 dent, in ihy chair. — The longitudinal impact of metal rods 

 with rounded ends (.second paper) : J. E. Sears. In this 

 paper the effect of the rounded ends is discussed mathe- 

 matically by means of a combination of the theories of 

 Hertz and St. Venant. Further experimental results are 

 brought forward for purposes of comparison. In these 

 experiments rods of unequal lengths were used, and observ- 

 ations made both of the durations of impact and of the 

 velocities of rebound. The results in nearly every case 

 agreed within i per cent, with those given by the theory. 

 'Interesting laws are found for the variation in the dura- 

 tion of the impact when the length of one of the rods is 

 continuously increased, and also for the case when the 

 velocity of impact is allowed to vary. The paper concludes 

 with a suggestion as to the application of the theory to 

 plane-ended rods, and a calculation of the stresses set up 

 at the ends of the rods during impact. — The fatigue of 

 secondary radiation due to radium rays : J. A. Crowther. 

 The object of the experiments was to ascertain if the con- 

 tinuous impact of the radium radiations upon a metal 

 plate over a prolonged period of time produced any alter- 

 ation in the amount of secondary radiation given out by 

 the plate. Experiments were made botli with the /3 and 7 

 ra5's, and also with the a rays. The results of the experi- 

 ments showed (i) that the continuous impact of radium 

 rays upon a metal plate does not cause any diminution 

 in the amount of secondary radiation given out by the 

 metal under the action of the radium rays themselves ; 

 (2) that the continuous impact of radium rays upon a 

 metal plate docs produce an alteration in the amount of 

 secondary radiation given out by the plate under the action 

 .of Rontgen rays, in amount similar to that produced by 

 the continuous impact of Rontgen rays ; (3) that the con- 

 tinuous action of radium rays produces a very marlced 

 diminution in the amount of secondary radiation given out 

 by the plate under the action of ultra-violet light. — Laws 

 of motion : P. V. Sevan. — lonisation by ultra-violet light : 

 Prof. Thomson. — The asymptotic approximation to func- 

 tions defined by highly convergent product forms : J. E. 

 Littlewood. 



P.ARIS. 



Academy of Sciences, December 9. — M. A. Chauveau in 

 the chair. — .\n apparatus designed for stars composed 

 partly of gas and partly of solid particles, and capable of 

 giving separately the image of each of the two elements : 

 H. Deslandres. .\ photograph of the star spectrum is 

 made, and from the negative a screen is made with a 

 diaphragm cutting out any desired lines, and this screen 

 is placed in the focal plane of the spectrum. K diagram 

 of the complete apparatus is given, which is arranged so 

 that the spectrum photographed may include either the lines 

 of both gas and solid particles or those of the gas or 

 particles separately. The apparatus is easily applicable to 

 comets, nebulse, the middle and upper chromosphere of 

 the sun during eclipses, and even the corona. — The sup- 

 posed poisonous nature of Hungarian beans : L. 

 Guignard. Contrary to the results obtained by MM. 

 Evesque, Verdier, and Bretin, the author has not been 

 able to obtain the smallest trace of hydrocyanic acid from 

 Hungarian beans (Haricots dc Hongrie). The method of 

 estimation of the hydrocyanic acid used by the above- 

 mentioned chemists is subjected to a critical examination, 

 and the author's own method described in detail. — The 

 claims of M. Loeb in the question of experiniental 

 parthenogenesis : Yves Delage. A reply to some criticisms 

 of M. Loeb on the author's work. — Some Lepidostrobus 

 from the Pyrenees region : R. Zeiller. Three illustrations 

 of the fossil are given. — The direct hydrogenation of some 

 aromatic diones : Paul Sabatier and A. Mailhe. The 

 direct hydrogenation by means of reduced nickel of the 

 aromatic diones gives results corresponding to the ordinary 

 hydrogenation of these ketones, aromatic hydrocarbons 

 being formed. Benzil and benzoin gave symmetrical 

 diphenylethane. Benzoylpropanone gave principallv butyl- 

 benzene. — The visibility of Saturn's ring at the present 

 time : J. Guillaume. .An account of the appearance of 

 the ring on the night of November 23. The results con- 

 firm the observations of W. C. Bond and of Serchi. — 

 The Giacobini comet 10070 : MM. Giacobini and Javelle. 



NO. 1990. VOL. y/l 



Observations of the position of the comet were taken on 

 Decemljer 4, b, and 7. The comet had a stellar appear- 

 ance of about 15" diameter, and showed a nucleus of the 

 fourteenth magnitude. — Observation of the transit of 

 Mercury of November 14 made at the Fabra Observatory 

 at Barcelona : J. Comas Sola. The conditions of observa- 

 tion were good. The times of the second, third, and fourth 

 contacts are given. The mean of five observations of the 

 equatorial diameter was 8"-94, the form of the planet being 

 sensibly circular. — Certain ruled surfaces : M. Tzitzeica. 

 — The permutation of the integrals of a system of 

 differential equations : A. Buhl. — The function D(A) of 

 Fredholm : T. Lalesco. — The systems of partial differ- 

 ential equations leading to (i) the study of the finite de- 

 formations of a continuous medium in space of n 

 dimensions ; (2) the determination of the s}-stems of ortho- 

 gonal curvilinear coordinates with n variables : M. 

 Riquier. — General mechanics : Eugfene and Francois 

 Cosserat. — An electromagnetic compass particularly suit- 

 able for armoured blockhouses and submarines : Louis 

 Dunoyer. The transmitting compass is placed in a part 

 of the ship where the field gives no trouble, or may be 

 compensated, the readings being transmitted by the 

 arrangement described to the receiver, from which the 

 ship is steered. — The number of free electrons of metals 

 and the electromotive series : V. Schaffers. — The con- 

 densation of water vapour in the presence of the radium 

 emanation : Mme. Curie. Moist air containing the radium 

 emanation always contains a fine fog more or less opaque, 

 and formed of very fine particles. A very much smaller 

 amount of water vapour than that required for saturation 

 is sufficient to produce this phenomenon, but it is not pro- 

 duced when the air is perfectly dry. This effect is quite 

 separate from the known phenomenon of condensation of 

 water vapour by gaseous ions. — The lithium contained in 

 radio-active minerals : Mile. Gleditsch. In view of the 

 observation of Sir William Ramsay that radium transforms 

 copper into lithium, it appeared of interest to see if 

 minerals which contain both copper and radium also con- 

 tain lithium. In agreement with the result of McCoy 

 (Nature, November 28), Joachimsthal pitchblende has been 

 found to contain a minute amount of lithium. — Singing 

 flames and tubes with flames of several notes : M. 

 Athanasiadis. Experiments are described showing that a 

 manometric flame can produce a perceptible sound, the 

 number of vibrations of which is equal to the number of 

 vibrations of the manometric membrane. A manometric 

 flame can also produce simultaneously two or more notes. 

 — The use of very low temperatures for spectrum analysis 

 and for the study of magneto-optic phenomena in solutions : 

 Jean Becquerel. — The propagation of telephone currents 

 through subterranean lines : Henri Abraham and M. 

 Devaux-Charbonnel. L'nderground telephone lines are 

 only available for very moderate distances ; the pitch of 

 the notes exercises a considerable influence on the power 

 of transmission to large distances, low voices oeing better 

 transmitted than high ones, as the line absorbs the high 

 harmonics. — The saturation intensity of magnetisation of 

 iron and nickel : Pierre Weiss. — The application of the law 

 of Poiseuille to the measurement of high pressures : A. 

 Perot. The volume of water forced through a very fine 

 capillary tube, applying Poiseuille's Law, has been used as 

 a basis of a manometer for high pressures, 300 kg. per 

 sq. cm. The accuracy was found to be about 0-5 per cent. 

 — The use of heavy hydrocarbons for lighting : Louis 

 Denayrouze. — The action of an incandescent electric con- 

 ductor on the gases which surround it : M. Couriot and 

 Jean Meunier. .An explanation is put forward of the 

 cause of the non-inflammation of certain explosive mixtures 

 of oxygen and hydrocarbons by means of a wire carried 

 to incandescence by electricity. It is assumed that the 

 wire repels the oxygen molecules and attracts those of the 

 hydrocarbon, so that the actual composition of the gaseous 

 zone immediately round the wire is not in explosive pro- 

 portions. — The method of limiting densities and its appli- 

 cation to the atomic weight of nitrogen : Ph. A. Guye. 

 An answer to some criticisms of M. Daniel Berthelot. 

 The author prefers to base his calculations on the idea of 

 corresponding states rather than on that of limiting densi- 

 ties, and compares the two methods in detail as applied 

 to the experimental ratios N„0 : O, N,0 : N,, N, : O, 

 NO : O, NO : N, and N : O. These lead to a mean valu' 



