Chemistry and Physics. 297 



ical relation c p /c v = 5/3, it was only necessary to determine k 

 experimentally in order to evaluate/'. Bannawitz found the tem- 

 perature coefficient y, in the equation k t = k (l + yt), to equal 

 0*00259 and also k — 0-0001091. Consequently, for neon at 

 10-1° C, k = 0-00011195. Hence /= 2-501, which is in perfect 

 experimental agreement with the theoretical value 5/2. — Ann. d. 

 Physik, vol. xlviii, pp. 577-592, November, 1915. h. s. u. 



7. Relativity and the Electron Theory ; by E. Cunningham. 

 Pp. vii, 96. London, 1915 (Longmans, Green and Co.). — "This 

 monograph is an attempt to set out as clearly and simply as possi- 

 ble the relation of the Principle of Relativity to the generally- 

 accepted Electron Theory, showing at what points the former is 

 the natural and necessary complement of the latter." In order to 

 make the text useful to the general reader and more especially to 

 the experimental physicist, the mathematical analysis has been 

 omitted or placed in the background as far as possible, and no 

 attempt has been made to describe at length such consequences 

 of the Principle of Relativity as would be for the most part 

 beyond the reach of experimental investigation. The experiments 

 leading up to the enunciation of the Principle are discussed in a 

 very lucid and interesting manner, and the entire text is admira- 

 bly designed to meet the needs of the readers to whom it is espec- 

 ially addressed. h. s. tj. 



8. The Telephone and Telephone Exchanges / by J. E. Kings- 

 buky. Pp. x, 558, with 170 figures. London, 1915 (Longmans, 

 Green and Co.). — In this book the inventions and developments 

 in the telephone field are discussed in such a manner as to consti- 

 tute a fairly complete history of the industry. The circumstances 

 leading up to the principal inventions, the developments resulting 

 from them, and the influences beai'ing on them are considered in 

 detail. The subject of exchange service necessarily involves the 

 technical, commercial, and political aspects of the subject. Many 

 quotations from original sources are incorporated. For example, 

 the evidence given by Bell in the various law suits concerning his 

 inventions has been appropriately interwoven in the text. In 

 some instances the author has been able to obtain and present 

 material which was heretofore inaccessible to the public. Thus, 

 authoritative information relating to the most important develop- 

 ments in switchboards, cables, and exchange service generally has 

 been derived first hand from the original reports of the committees 

 and conferences of experts of the Western Electric Company and 

 of other American Companies. Interest in the subject is enlivened 

 by quotations from letters and personal conversations between 

 noted scientists. The author's style is clear and pleasing, the 

 line diagrams and half-tone figures are excellent, and the text is 

 unquestionably a valuable contribution to the history of the 

 subject. h. s. u. 



9. A Course of Modern Analysis; by E. T. Whittaker and 

 G. N. Watson. Second edition, completely revised. Pp. 560. 

 Cambridge, 1915 (University Press). — The text is divided into 



