Notices respecting New Books. 725 



the volume ; this is followed by the memoirs, a biographical sketch 

 of the author being appended to each memoir. The bibliography 

 and index at the end of each volume form useful features. 



In a few cases, where the papers seemed of excessive length, 

 some portions have been left out ; such omissions have, however, 

 been indicated in every case, and as a good deal of judgment 

 appears to have been exercised in the matter, the arrangement has 

 not detracted from the value of the papers. We hope that the 

 publishers will see their way to add to this most useful series of 

 scientific classics. 



SicJithare unci Unsiclitbare Bewegungen. Von H. A. Loeentz. 

 Unter Mitwirkung des Yerfassers aus dem Hollandischen 

 iibersetzt von Gr. Siebert. Mit 40 eingedruckten Abbildungen. 

 Braunschweig: P. Yieweg und Sohn. 1902. Pp.123. 



It is not every distinguished man of science that condescends to 

 write a popular book ; and in many cases the attempt when mado 

 is hardly a success. But there are notable exceptions ; and a perusal 

 of the book before us has convinced us that Prof essor Lorentz's gift 

 of clear exposition attains to the same high standard of excellence 

 as that which characterizes his scientific work. 



The book before us is the outcome of a course of seven lectures 

 which the author was asked to deliver to a non-scientific audience, 

 and forms most interesting reading. After expounding the leading 

 principles of dynamics in the first three lectures, which are entitled 

 respectively " Rectilinear Motion,''" " Curvilinear Motion,'" " Wave- 

 Motion. Light- Waves," the author considers, in Lecture IV., the 

 subject of Light in greater detail, especially in connexion with 

 Spectrum Analysis. This is followed in Lecture V. by " Molecular 

 Motion " — including a sketch of the kinetic theory of gases. 

 Lecture VI,, on " Electrical Phenomena," is one of the most 

 interesting in the book, as it contains a simple exposition of the 

 electronic theory and the Zeeman effect. Lecture VII. is intended 

 as a sort of resume and expansion of the preceding lectures, con- 

 sidered with special reference to the principle of the Conservation 

 of Energy. 



The book is one which may be read with pleasure and profit by 

 the advanced student as well as the general reader. 



Electrochemical Industry. Vol. I. No. 1. 929 Chestnut St., 

 Philadelphia, Pa., U.S.A., September, 1902. 



The appearance of a new periodical devoted entirely to the electro- 

 chemical industry is a healthy sign of the development of that 

 industry in the "United States. The first number promises well. 

 It contains several interesting articles by well-known experts, 

 one of the most striking of which is " Niagara as an Electro- 

 chemical Centre." We heartily wish the new periodical every 

 success. 



