Chemistry and Physics. 75 



German text, but has made many changes and additions, par- 

 ticular!}' in laying greater stress upon the theoretical side of the 

 subject in connection with the applications of the principles of 

 mass action, the ionization theory, and the theory of oxidation 

 and reduction. The first part of the book comprising 76 pages 

 is devoted to general principles and presents in an excellent man- 

 ner the important theories bearing upon the subject. It is to be 

 hoped that the student is not expected to learn this part thor- 

 oughly before beginning the study of qualitative analysis, for 

 without a basis of many facts much of the theory would be very 

 difficult to understand. The second part of over 200 pages deals 

 with the metals, while the remaining parts deal with the acid 

 constituents, systematic analyses, and the reactions of some 

 of the rare elements. The descriptive parts are very com- 

 prehensive and equations of reactions are liberally supplied. 

 Many equations are given in the ionic form, but this feature is 

 not carried far enough to be particularly objectionable. The 

 analyses are given in tabular form, but each of the tables is 

 accompanied by a full description of the procedure, to which con- 

 venient reference is made by numbers in the tables. It is a very 

 excellent text-book, containing a vast number of facts, and giving 

 very satisfactory methods of qualitative analysis. Its use in this 

 country has been very extensive, and the new and improved 

 edition will undoubtedly add to its popularity. h. l. w. 



4. A System of Physical Chemistry ; by William C. McC. 

 Lewis. 12mo, 2 vols. Pp. 523 and 552. London, 1916 (Long- 

 mans, Green and Co. Price $2.50 per vol. Sold separately). 



This book is of quite different character from most treatises on 

 physical chemistry. As the two volumes indicate, the treatment 

 is far more elaborate than in many text books, while it is not in 

 any sense a reference book like Ostwald's lehrbuch. It might per- 

 haps be classed as a treatise on chemical physics than on physical 

 chemistry. The arrangement of the book is interesting. It 

 " consists in regarding all physico-chemical phenomena as being 

 capable of separation into two classes: first, phenomena exhibited 

 by material systems when in a state of equilibrium ; and, secondly, 

 phenomena exhibited by material systems which have not 

 reached equilibrium." In the first volume, the two classes of 

 phenomena are treated from the standpoint of the kinetic theory 

 while the second volume is devoted to considerations based on 

 thermodynamics. As an illustration, equilibrium from the stand- 

 point of the law of mass-action is considered in the first volume, 

 while the application of the phase rule to equilibrium is in the 

 second. In fact, equilibrium is the main subject in both volumes, 

 but treated in each from an entirely different standpoint. 



The newer developments of physical chemistry are given full 

 consideration. Thus, some forty pages are devoted to Nernst's 

 heat theorem, which formed the basis of his Silliman lectures at 

 Yale a few years ago. 



The book should prove of great interest and value to advanced 

 students. h. w. f. 



