Notices respecting New Books. 1007 



with here, an account is given of the phenomena of radioactivity. 

 Curiously enough, these are given, and are the only phenomena 

 described, under the head of photo-chemistry, while their photo- 

 graphic properties are barely mentioned. A short account of 

 photo-chemistry would be a valuable addition and might replace 

 the account of radioactivity which is not called for. 



Annuaire pour Van 1911. Published by the Bureau des Longi- 

 tudes. Paris : Gauthier-Villars. 1 £r. 50 c. 

 Besides the usual astronomical and geographic data, this issue 

 contains several important articles. One of these, by M. A. de 

 Gramont, on Stellar Spectra, replaces that of M. Cornu in previous 

 issues. In it will be found a very useful summary of the present 

 state of knowledge on this interesting subject. It includes a com- 

 parative table of the several modes of classification adopted by 

 different investigators. M. H. Poincare summarizes the contri- 

 butions to the XVIth Conference of the International Geodesic 

 Association at London and Cambridge (1909) : and M. G. Bigourdan 

 gives particulars in regard to the total (annular) eclipses of the sun 

 of 1912, the line of totality of which passes close to St. Germain 

 in Prance. 



A Treatise on Electrical Theory and the Problem of the Universe. 



By G. W. de Tunzelmann, B.Sc. Charles Griffin & Co., Ltd. 



London, 1910. 

 The appearance of this book is very timely. It brings together 

 in a form fairly intelligible to a nou-mathematical render the 

 most important recent developments of modern electrical theory. 

 But modern electrical theory now governs the whole domain of 

 physical science ; and the time may not be far distant when 

 Maxwell's joke about " the unit of life and of thought " may 

 find its scientific verification in the negatively charged corpuscle. 

 Some thirty or forty years ago it was a kind of accepted axiom 

 that the simplicity of a theory was one of its strongest claims to 

 acceptance: mais nous avons change tout cela. The "jelly" 

 theory of the aether has had to go, and aether twists have entered 

 into possession. All physical laws as they appeal to our finite 

 intelligences are simply statistical averages of whirling and 

 drifting movements. Each so-called atom of matter is a complex 

 system of discrete particles or corpuscles all in more or less rapid 

 motion, acting and reacting on one another and on the mysterious 

 aether in which they move. The rapidly moving negative cor- 

 puscle drags along with it through the aether its trails of mag- 

 netic and electric lines of force, and at every change of velocity 

 starts waves of radiant energy through the aether. All this and 

 a vast deal more are expounded in the pages of Mr. Tunzelmann's 

 book. Although much wider in scope and more deep seated in its 

 foundations, this exposition of Electrical Theory may be compared 

 to Lloyd's treatise on the Wave Theory of Light, which in its 

 day did more to spread a general knowledge of the labours of 

 Young and Fresnel than any other book. So here. Mr. Tunzel- 

 mann has taken a wide grasp of all the essential features of this 



