290 Notices respecting New Books. 



rapid chemical change may be brought about by non-electrical 

 double decomposition. This idea is supported by an obser- 

 vation of Kahlenberg on the instantaneous production of a 

 precipitate of copper chloride when hydrochloric acid is 

 passed into a non-conducting solution of copper oleate in 

 benzene. It is evident that such an observation indicates 

 that, in the particular solvent used, chemical action may 

 occur which is not correlated with electrolytic conductivity, 

 but it does not in the least weaken the electrical and osmotic 

 evidence which we have adduced above in favour of the 

 theory of the ionic dissociation of the aqueous solutions of 

 electrolytes. 



XXVI. Notices respecting New Books. 



Annuaire pour VAn 1903, Publie par le Bureau des Longitudes. 

 Avec des Notices Scientifiques. Paris : G-authier-Villars (55 quai 

 des Grands- Augustins). Pp. viii-f-808. Price 1 fr. 50 c. 



THIS important annual contains, besides the usual astronomical, 

 physical, and chemical tables, a number of specially contributed 

 articles, the most important of which are : — " Shooting-Stars and 

 Comets," by R. Badau ; " Science and Poetry/' by J. Janssen ; 

 "■ On the Work carried out at the Mont Blanc Observatory," by 

 J. Janssen ; and the speeches delivered by a number of distinguished 

 French scientists as a tribute to the memory of the late A. Cornu 

 and that of II. Faye. 



Compte Rendu du deuxieme Congres International des Mathematiciens, 

 tenu a Paris de 6 au 12 Aout 1900. Proces-verbaux et Communi- 

 cations, publiespar E. Dupokcq. Paris: Grauthier-Villars, 1902. 



Almost every department of mathematics, pure and applied, is 

 touched on in this volume ; and a mere glance through its pages 

 cannot fail to be instructive to mathematicians of all classes. 

 Cantor contributes a paper on the Historiography of the science ; 

 Volterra an interesting estimate of the careers and labours of Betti, 

 Brioschi, and Casorati. Hilbert discusses at considerable length 

 the future problems of mathematics ; Poincare the role of intui- 

 tion and logic; and Mittag-Leiner reproduces, with comments, 

 some important letters of Weierstrass to Sophie Kowalewski. Then 

 follow some thirty papers of various lengths upon the theory of 

 numbers, analysis, geometry, dynamics, history, and methods of 

 teaching. At one of the meetings some discussion arose in regard 

 to the proposed adoption of Zamenhofs artificial language Esperanto 

 as a universal language in science and commerce ; but although the 

 growing disadvantages attending the publication of scientific papers 

 in so many different languages were fully recognized, the motion 

 carried was that of Vassilief, that Academies and Societies study 

 the means for remedying the evil at present existing. 



