462 Scientific Intelligence. 



bined action of a magnetic and an electric field were observed. 



e 

 The results obtained by Wien for — , viz.: 10 4 , was confirmed 



m 



for the more deflected rays, while 5 x 10 3 was obtained for the 

 lesser deflected ones. The apparatus resembled that employed 

 by Wien, except that one very fine hole was made in the cathode 

 through which the canal rays passed. This fine column of rays 

 was deflected by a very powerful magnet of the Du Bois type ; 

 and great care was taken to screen the dischai'ge tube from the 

 magnetic field. The tube was enclosed in a soft iron vessel, 

 which, however, allowed the canal-ray tube to project from the 

 vessel. The author discusses reasons for the existence of a con- 

 tinuous band of phosphorescence produced by the united action 

 of the magnetic and electric fields. The value obtained for 



- are mean values : for the positive particles in their passage 



through the canal-ray tube may lose a part of their charge by 

 collision or otherwise. The positive rays were investigated for 

 hydrogen, helium and argon, and also in gases at very low pres- 

 sures. — Phil. Mag., May, 1907, pp. 561-575. j. t. 



10. Electrons; by Sir Oliver Lodge. Pp. xv + 230. London, 

 1906 (George Bell & Sons). — The author has succeeded admir- 

 ably in fulfilling the requirements suggested by the last sentence 

 of his preface, namely : " The present book is intended through- 

 out for students of general physics, and in places for specialists^ 

 but most of it may be taken as an exposition of a subject of 

 inevitable interest to all educated men." Merely as a parentheti- 

 cal remark, the reviewer cannot refrain from quoting a sentence 

 from page 203 which seems to be framed for " specialists" and not 

 for more general readers. It is as follows : " Especially must the 

 inner ethereal meaning both of positive and negative charges be 

 explained : whether on the notion of a right-and-left-handed self- 

 locked intrinsic wrench-strain in a Kelvin gyrostatically stable 

 ether elaborated by Larrnor, or on some hitherto unimagiued 

 plan." The fundamental conceptions and problems associated 

 with the theory of electrons are developed clearly and logically. 

 One attractive feature of the book is the confidence which the 

 manner of presentation inspires in the reader. Quite a number 

 of the more or less popular books on the nature of electricity, of 

 matter, and of radio-activity which have been published in the 

 last five years give the impression of unpreparedness, in the sense 

 that the authors seem to have read the texts of J. J. Thomson, 

 Rutherford and others in a somewhat superficial manner and then 

 to have presented the most important facts in their own language, 

 but without possessing such real convictions as can alone come 

 from long experience in a given subject. It is just the reverse 

 with the book under consideration. Not only does the author 

 write in an authoritative manner but he is thorough in details. For 

 example, he places stress both on the retention of k and fi in 



