500 SCIENCE PROGRESS 



from the stock collections used in various Technical Institutions in the United 

 States. About 600 of these exercises deal with various branches of Mechanics, the 

 remainder with Heat, Light, Sound, and General Physics. They are of all degrees 

 of difficulty, and are arranged under the names of the Institutes from which they 

 are borrowed, and not (primarily) under subject headings. The next section is a 

 reprint from Gordon's Mechanics of the mathematical development of that subject 

 on an energy basis, and finally there is a collection of sixteen laboratory exercises. 

 Thirteen deal with Elementary Mechanics, and are based on the course devised 

 by Prof. Duff for use at Worcester Polytechnic Institute, while the remainder 

 are " original " (?) experiments in Sound and Optics, based on work done at 

 Cornell University. 



From this catalogue of contents it will be seen that Prof. Dunwoody's book 

 contains a hotchpotch which is unlikely to obtain a favourable reception at the 

 hands of the English reader. 



D. O. W. 



CHEMISTRY 



Outlines of Theoretical Chemistry. By Frederick H. Getman, Ph.D., 

 formerly Associate Professor of Chemistry in Bryn Mawr College. Second 

 Edition, revised and enlarged. [Pp. xvii 4- 539.] (London: Chapman and 

 Hall, Ltd., 191 8. Price 16s. 6d. net.) 



The great difficulty that confronts one, on attempting to summarise the funda- 

 mental laws of chemistry, lies in the fact that many of the more important facts 

 of chemistry are incapable of being described in a few words — for instance, the 

 orientation of substituents in the benzene nucleus, the colours, odours, and 

 physiological action of substances, or the real underlying reasons for the differences 

 in the dissociation constants of acids, none of which are at present susceptible of 

 mathematical treatment, so that authors who deal with the subject are of necessity 

 forced to confine themselves to those laws which can be expressed more or less 

 accurately in mathematical form, for which reason it would often be more accurate 

 to describe works, such as that under review, as textbooks or outlines of Theoretical 

 Physical Chemistry. 



Subject to this reservation, however, we can heartily commend Prof. Getman's 

 work to those teachers seeking for a short and succinct account of the basic 

 physico-chemical laws with which we are at present acquainted. Prof. Getman 

 has taken the opportunity offered by the issue of a second edition of his book to 

 bring it up to date, the chief points of difference from the earlier edition consisting 

 in the introduction of chapters on radio-activity and the modern conception of the 

 atom, the substitution of a chapter on X-rays and crystal structure in place of 

 the chapter on crystallography, the rewriting of the chapter on colloids, the 

 insertion of a short sketch of Perrin's remarkable researches on the Brownian 

 movement and its bearing on molecular reality, the enlargement of the chapter on 

 Electromotive Force, and the addition of anew chapter on Photochemistry. 



The work is well and concisely written, and clearly illustrated with numerous 

 diagrams, and the student who has read and understood the book need have no 

 fears of examinations, and can remain assured that he possesses a very real and 

 accurate knowledge of the fundamental physico-chemical laws. 



F. A. M. 



