o40 Notices respecting New Books. 



components towards the violet. The theory given by Vol gt"^ 

 and that by myself t both lead to the conclusion that the 

 lateral component towards the violet should be at a greater 

 distance from the undisturbed line than the lateral component 

 towards the red. It may well be that in some cases this 

 cause may be more effective than those which produce un- 

 .symmetrical broadening towards the red, and consequently 

 broadening towards the violet would be the net result. 



LXVII. Notices respecting Neio Books. 



Aide-Meinoire de FhotO(jrapliie pour 1903. Puhlie soup, les auspices 

 de la Societe Photograjyhique de Toidouse par C. Fa-bre. Paris: 

 Gauthier-Vihars. 1903. Pp. 240. 



T^HIS useful little annual is divided into three parts. The first part 

 contains a review of the progress made in photography daring 

 the preceding year, and a complete list of photographic societies 

 and periodicals (both French and foreign). The second part is a 

 concise treatise on the fundamental principles of photography, and 

 contains many useful hints. The concluding part forms a trade- 

 directory. 



Thermodi/namiJc. Von Dr. A\^. Voigt, Professor der theoretischen 

 PJiysiTc an der Universiidt Gbtiingeyi. 1 Band. Mit 43 Piguren 

 [Samralung Schubert XXXIXJ. Leipzig : Gr. J. Goschensche 

 A^erlagshandlung. 1903. Pp. xv4-360. 



Tke subject of thermodynamics is probably one of the most dif- 

 ficult branches of mathematical physics, and abounds in pitfalls to 

 the unwary. Several excellent textbooks on it have appeared 

 recently, and most of them are distinguished from the older books 

 by the care bestowed on the foundations of the subject, and the 

 detailed manner in which the various assumptions on which the 

 theory is based are explained. 



The book under review is the first volume oi: a self-contained 

 and comprehensive treatise on the subject. The plan adopted by 

 the author consists in proving all the dynamical propositions 

 required in thermodynamic theory, instead of referring the reader 

 to special treatises on dynamics. The book opens with an intro- 

 duction in which the subjects of thermometry, calorimetry, and 

 heat conduction are dealt with. Then comes Chapter L, on the 

 energy equation and the dynamical equivalent of heat. Chapter XL 

 contains the thermodynamics of an ideal gas. Chapter III. is 

 devoted to the thermodynamics of bodies whose state is completely 

 defined by two independent variables (especially bodies under a 

 uniform pressure), and the concluding Chapter IV. deals with the 



* A72nalen der Phi/sil; vol. i. p. 376 (1900). 

 t Phil. Mag. Feb. 1902. 



