166 SCIENCE PROGRESS 



Principles of Physical Chemistry. By Edward W. Washburn, Professor of 

 Physical Chemistry in the University of Illinois. [Pp. xxv + 442, with 

 61 illustrations.] (New York and London: McGraw-Hill Book Co., 191 5. 

 Price 15s. net.) 



PROF. WASHBURN'S reputation as a physical chemist is such that a book from his 

 pen is likely to meet with a good reception. The present text-book is a valuable 

 addition to the somewhat limited number of manuals of Physical Chemistry 

 written in English and intended for English-speaking readers. The scope of the 

 work will be evident from the chapter-headings, viz. the structure of matter and 

 the composition of substances, the gaseous state of aggregation, the liquid state 

 of aggregation, liquid-gas systems, the crystalline state of aggregation, crystal-gas 

 systems, crystal-liquid systems, relations between physical properties and chemical 

 constitution, Brownian movement and molecular magnitudes, some principles 

 relating to energy, solutions (4 chapters), the colligative properties of solutions of 

 electrolytes, the conduction of electricity, conductance and degree of ionisation, 

 electrical transference, thermochemistry, heat capacity and internal energy, 

 chemical kinetics, chemical equilibrium involving the ions of water, the phase 

 rule, disperse systems, radioactivity, atomic structure and periodic system, 

 and finally an appendix dealing with certain thermodynamic derivations. The 

 author has contrived to compress all this inside 420 pages, a not inconsiderable 

 feat, for the result is by no means a " cram " book. Both kinetic theory and 

 thermodynamics are freely employed throughout. The greatest difficulty for the 

 reader is to understand the arrangement of the matter dealt with. Each chapter 

 is in itself excellent, but it is difficult in some cases to see why a given chapter 

 occurs where it does. The author himself, as we infer from his preface, has been 

 guided much more by teaching considerations than by an attempt to give the 

 whole subject an atmosphere of unity. To come to some points of more detail. 

 One of the most striking features of the book is the treatment of solutions. 

 Solutions are divided into two great classes, namely, solutions of constant 

 thermodynamic environment, and solutions whose environment is a function of 

 the concentration. To the first belong ideal and dilute solutions ; to the second, 

 concentrated solutions and solutions of electrolytes. All the usual properties of 

 solutions are discussed from this point of view. Prof. Washburn has very decided 

 views regarding the inadmissibility of identifying osmotic pressure with gas 

 pressure in spite of their formal identity in dilute solution. The problem of 

 electrical conduction in solutions is fairly fully dealt with, though in the opinion of 

 the reviewer the author has shown too great modesty in the chapter on electrical 

 transference by not including an account of his own very accurate measurements 

 by the reference-substance method in addition to the short table of results given 

 on p. 232. 



In a book of this size, in which at the same time certain subjects (such 

 as solutions) are treated particularly fully, it is inevitable that some subjects 

 are omitted. Thus photo-chemistry is dealt with in a single paragraph, electro- 

 motive-force is practically not considered, and affinity is not even mentioned. On 

 the other hand, the recent work on atomic heats, especially the applicability of 

 Debye's equation, is discussed very clearly, as is also von Weimarn's theory 

 of disperse systems, the determination of the charge on the electron, whilst room 

 is also found for a brief reference to the work of Laue and the Braggs upon X-rays 

 and crystal structure. In short, what Prof. Washburn has undertaken to expound 

 has been done in a masterly way. It would have been eminently desirable had 



