February io, 1910] 



NATURE ^ 



449 



francs. — E. Esclangron : Observation of Drake's comet. 

 A description of the appearance of the Johannesburg 

 comet on January 22 at Bordeaux. — H. Bourgret ; 

 Observations of Drake's comet (1910a) made at the 

 Observatory of Marseilles. Positions of the comet 

 are given for January 19, 20, and 21. — Remarlis by 

 M. Baillaud on this paper, giving an account of other 

 dates and places in France where observations of the comet 

 had been made. — E. IVIauba.nt : The elements of Tempel's 

 comet. — J. Le Roux : The conditions of maximum 

 or minimum of an analytical function with an infinity of 

 variables. — D. Mirimanoff : The last theorem of Fermat. 

 — M. Galbrun : The representation of the solutions of a 

 linear equation of finite differences for large values of the 

 variable. — Paul Helbronner : The connections of the 

 meridian chain of Savoy with the fundamental Italian and 

 Swiss triangulation.- — Edm. van Aubel : Pulfrich's relation 

 between the volume contraction and the refractive power 

 of mi.xed liquids. A discussion of the experimental data 

 of R. Wintgen on the density and refractive indices of 

 solutions of salts and acids from the point of view of the 

 formula of Pulfrich. — P. Vaillant : The laws of evapora- 

 tion. In the apparatus devised by the author the quantity 

 of liquid evaporated per second is independent of the nature 

 of the liquid, depending only on the area of the opening 

 through which the vapour of the liquid escapes. An 

 examination of numerous liquids led to the relation 

 g = oMF*, in which q is the rate of evaporation per second, 

 F the maximum vapour pressures of the liquids at the 

 temperature of the experiments (20° C), and o an approxi- 

 mate constant. To fall into line with the other liquids, it 

 is necessary to attribute the molecular weight (H,0), to 

 water. — C. Fery : Prisms with curved faces applicable to 

 spectroscopy. The object of the arrangement described 

 and figured is to reduce the spectroscope to the slit, prism 

 and ocular, or photographic plate. The arrangement 

 possesses advantages in stellar spectroscopy. — Gaston 

 Gaillard : Observation of a dissymmetry in the velocity of 

 solution of crystals of sugar along the different faces. — 

 J. Chaudier and Ed. Chauvenet : The radio-activity of 

 ■ the halogen and oxyhalogen compounds of thorium. The 

 radio-j; tivity of these compounds of thorium for quantities 

 of substance containing more than 10 milligrams of 

 thorium varies with the nature of the associated elements. 

 The intensity of the radiation diminishes as the atomic 

 weight of these elements increases. The curves of radio- 

 activity of the various compounds of thorium tend towards 

 that of thorium as the quantities of material are reduced. 

 — Pierre Camboulives : The action of carbon tetra- 

 chloride vapours upon some minerals. Many natural o.Kides 

 are attacked by the vapours of carbon tetrachloride as 

 easily as the oxides prepared in the laboratory. Corundum 

 offers an exception, being attacked only to the extent of 

 II or 12 per cent., whilst alumina arising from the calcina- 

 tion of ammonia alum is completely transformed. Wolfram 

 is so readily acted upon that the process forms the basis 

 of a good analytical method. Silicates are the more readily 

 acted upon the poorer they are in silica. Numerous 

 examples are given. — F. Kerforne : An auriferous lode 

 situated at BesM (Loire-Inf^rieure). An account of some 

 ancient gold workings. — Ch. Moureu and J. Ch. 

 Bongfrand : Carbon subnilride, C,N,. This substance, 

 which is the second definite compound known of carbon 

 and nitrogen, is formed bv the removal of water from 

 butine diamide, NH,— CO— C = C— CO— \H., and hence 

 has the constitution \ =C — C = '" — C = N'," or dicyan- 

 acetylene. It forms fine white needles, melting at 21° C. 

 and boiling at 76° C. under a pressure of 753 mm. Its 

 vapour is violently irritating, and catches fire in the air 

 at a temperature of about 130° C. Particulars are given 

 of the analysis, determination of the vapour density and 

 molecular refraction, and further work is being carried 

 out on its physical and chemical properties. — Maurice 

 Lombard : The chemical and biological effects of the ultra- 

 violet rays. The formation of nitrites in these experiments 

 is definitely proved. — Gabriel Bertrand and M. Holderer : 

 New observations on the individuality of cellase. Details 

 of experiments proving that cellase is a specific diastase. 

 It is found, more or less mixed with other species of 

 diastases, in barley, almonds, the mycelium of Aspergillus 

 iiiger, &c. — M. Maragre : The photography of the voice in 

 NO. 2102, VOL. 82] 



practical medicine. The photography of the vibrations of 

 the larynx shows very clearly the state of the voice at the 

 beginning and end of a course of treatment. Its use as 

 an aid to diagnosis is being further examined. — A. 

 Rosenstiehl : The consequences of Young's hypothesis. 

 The sensation of binary white. — P. Hachet-Souplet : The 

 association of sensations in animals. The law of recur- 

 rence. — A. Lecaillon : The structure and signification of 

 the membrane which envelops the vitelline sphere in the 

 egg of birds. — L^on VV. Collet : The presence of fossil- 

 bearing Cenomanian in the limestone Alps of Haute Savoie. 

 — E. de Martonne : The genesis of Alpine glacial forms. 

 — Kr. Birkeland : The magnetic deviability of the cor- 

 puscular radiations proceeding from the sun.- — Alfred 

 Angrot : The earthquake of January 22, 1910. The 

 seismograph of the Pare Salnt-Maur Observatory recorded 

 a distant earthquake of great violence on January 22. The 

 examination of the seismograms showed that the epicentre 

 was about 3000 kilometres to the south-east. Observa- 

 tions from other stations are required to fix the direction 

 with certainty. — Bernard Brunhes : The record of an 

 earthquake on January 22, 1910, at the Puy de D6me 

 Observatory. The seismograms indicated 3000 to 3500 kilo- 

 metres as the distance of the epicentre. 



January 31. — M. Emile Picard in the chair.— H. 

 Deslandres, A. Bernard, and L. d'Azambuja : First 

 observations of Drake's comet at the Observatory of 

 Meudon. Spectroscopic observations were possible on 

 January 22, 24, 25, 27, 29, and 30. Changes in the 

 comet's spectrum were observed during these days. At 

 first the sodium line was the most marked, together with 

 a faint hydrocarbon band. The strength of the sodium line 

 diminished from day to day, the hydrocarbon bands in- 

 creasing in clearness and the bands of cyanogen appearing. 

 On the last two days the sodium line became invisible, but 

 the spectra of the hydrocarbons and cyanogen became 

 complete and intense. The spectrum of the hydrocarbons 

 even appeared to extend a considerable distance into the 

 tail. These changes are exactly those undergone by the 

 large comet of 1882. — B. Baillaud : The photographic map 

 of the sky. Presentation of the proceedings of the last 

 congress.— A. Muntz : The mud carried away by the waters 

 of the Seine. Determination of the amount of mud in 

 suspension in the Seine shows that the total amount 

 carried away by the river between January 25_ and 29 

 varied from 18,800 to 11,000 tons per day. This is not 

 regarded as causing a serious loss of fertility in the soil 

 from which this mud has been removed. — Edmond Perrin 

 gave an account of the state of the museum after the 

 floods. — Henri Douville : The discovery of the marine 

 Trias at Madagascar. — M. Giacobini : Observations 

 of the comet 1910a made at the Observatory of 

 Pari- with the ^S-cm. equatorial. Positions are given 

 for January 22, 24, 25, 27, 29, and 30. — P. Chofardet : 

 Observations of the Johannesburg comet, igioa, made at 

 the Observatory' of Besan(;on with the bent equatorial. 

 Positions given for January 27 and 29. — Ch. Lallemand : 

 A systematic error in the determination of the mean level 

 of the sea by the medimaremeter. In this instrument, 

 consisting of a tube closed at the lower end by a porous 

 pot, the water-level oscillates round the mean sea-level. 

 The systematic error now discovered is due to the removal 

 of a few drops of water each time a tube is introduced to 

 take the level. On this account the readings of the 

 instrument are 1-5 mm. too low. — M. Biquard : A method 

 of measuring the coefficient of thermal conductivity of 

 badly conducting bodies. In the instrument described the 

 heat is transmitted regularly through isothermal surfaces, 

 the amount being measured by the rate of production of 

 water from ice. — G. Thovert : Diffusion and the kinetic 

 theorv of solutions. An extension of the method previously 

 described to solutions in methyl alcohol. — Ch. Fabry : The 

 intrinsic brightness of the starry sky. — J. H. Russen- 

 bergrer : The absorption of liquids by norous substances. 

 — F. Laporte and P. de la Gorce : Researches on the 

 electrochemical equivalent of silver carried out at the 

 Central Electrical Laboratory. Successive improvements 

 introduced into the purification of the silver nitrate used 

 in these exoeriments have resulted in the removal of the 

 difference of 00004 oricinally found between the determina- 

 tions of the National Physical Laboratory and those made 



