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XVIII. Notices respecting New Boohs. 



James Clerk Maxwell and Modem Physics. By B,. T. GtLAzebrook, 

 F.R.S. (Century Science Series.) London: Cassell & Co., 1896. 



OOME fourteen years have now elapsed since Prof. Campbell and 

 ^ Mr. G-arnett published their biography and letters of Maxwell ; 

 the shock occasioned by his death had then scarcely passed away. 

 At that time, although all regarded him as one of the founders of 

 modern physics, few even among physicists realized the magnitude 

 of his discoveries and research, and probably none imagined that 

 his ideas concerning the aether would so soon receive the remark- 

 able development which they have derived from the life-work of 

 Hertz. For, so far as regards the problem of the aether, Hertz 

 has been the chief exponent of Maxwell, just as Maxwell had 

 previously explained and extended the views of Faraday. But 

 Maxwell contributed by his laboursto many other physical questions, 

 everywhere not only adding to the stock of knowledge but 

 furnishing suggestions for future work. Mr. (xlazebrook gives, in 

 a form suited to the general reader, a brief account of Maxwell's 

 work in three of these departments of knowledge — the properties 

 of Cartesian ovals, the theory of compound colours, and the 

 dynamical theory of gases. He reserves a longer chapter for the 

 electrical theories, of which a very concise account is given, as 

 clear as the mathematical nature of the subject will allow in a 

 non-mathematical volume. 



It should not be forgotten, however, that Maxwell was not only 

 a great thinker and experimenter, but also an organizer. The 

 present school of physics at Cambridge owes its existence aud 

 much of its efficiency to him, and has served as a model for the newer 

 provincial colleges. It is fitting that the story of Maxwell's work 

 should be told by oue so intimately acquainted with his Cambridge 

 life as Mr. Glazebrook, and more especially by one who has had 

 the good fortune to call him master and friend. J. L. H. 



An Elementary Treatise on the Integral Calculus, containing 



Applications to Plane Curves and Surfaces, and also a Chapter on 



the Calculus of Variations, with numerous Examples. By 



Benjamin Williamson", F.R.S. (Longmans : pp. xviii + 512.) 



This is the seventh edition of a work which first saw the light in 



1875, in the humble guise of pp. vii-f-267. It has thus attained 



its majority and enormously increased in importance. On the 



appearance of the sixth edition in 1891 we noted the great 



advances that had been made on former editions, so that in the 



case of so well-known a work it is only necessary to point out the 



new features. The Calculus of Variations, which in the last 



edition formed chapter xv. with some 34 pages only, is now 



chapter xvi. and, in two sections — " Single Integrals and Multiple 



Integrals," — now occupies double the space. Another novelty is 



chapter xv. (12 pp.), " on the Sign of Substitution/' inserted 



principally " with a view to its employment in the Calculus of 



Variations." This symbol Dr. Williamson states was first 



Phil. Mag. S. 5. Vol.42. No. 255. Aug. 1896. Q 



