Chemistry and Physics. 77 



matters in connection with excise supervision in Great Britain. 

 Chapter 8 discusses the principles of the internal combustion 

 engine and its efficiency. In Chapter 9 the chemical and physi- 

 cal properties of alcohol are presented in full detail both by tables 

 and by diagrams. Chapter 10 summarizes with considerable 

 detail the results of alcohol-engine tests with regard to per- 

 formance and efficiency. These compare very favorably with 

 gasolene-engine tests except in the matter of fuel consumption. 

 Apparently the price of alcohol will have to fall considerably 

 below that of gasolene before it can be regarded as a commercial 

 competitor. 



Another and more promising line of attack on the motor fuel 

 problem is in the direction of mixtures of alcohol with other 

 easily volatile substances such as ether or benzol, or even with 

 gases such as acetylene. 



The final chapter (11) discusses various proposals of this 

 nature but the subject is too extensive to receive adequate treat- 

 ment in a book of this character. Appended to each chapter will 

 be found a useful and numerous list of references to the particu- 

 lar topics which have been under discussion. f. e. b. 



7. The Journal of Scientific Instruments.— The Institute of 

 Physics (England) in connection with the National Physical 

 Laboratory proposes to publish a journal devoted to the theory, 

 construction and use of instruments as an aid to research in all 

 branches of science and industry. The preliminary number 

 appeared in May. To assure its continued existence a subscrip- 

 tion list of about 3,000 is desired. f. e. b. 



8. La Theorie Einsteinienne de la Gravitation; by Gustave 

 Mie, translated from the German by J. Rossignol. Pp. xi, 118. 

 Paris, 1922 (J. Hermann). — This little volume contains a clear 

 and readable exposition of the relativity theory and Einstein's 

 theory of gravitation couched in simple language and free from 

 mathematical symbols. It should appeal to the reader who has 

 a knowledge of the principles and laws underlying the subject of 

 physics, but who is not conversant with the somewhat compli- 

 cated differential geometry involved in a detailed presentation of 

 the general relativity. The author 's emphasis on the philosophi- 

 cal aspects of the subject should make the book particularly 

 interesting to those philosophers who are looking for a clear and 

 simple account of the revolutionary changes in our concepts of 

 space and time which the relativity principle has occasioned. 



A short mathematical appendix (11 pages) added by the trans- 

 lator presents in condensed form the author's derivation of 

 Einstein's law of gravitation. l. p. 



