REVIEWS 



Preliminary | mathematics | by | Prof. F. E. Austin, B. S., E. E. | Hanover, 

 N. H. I [7 lines]. | Copyright 1917, pp. 1-169— i-iv. Cloth, price $1.20. 



In the introduction the author seems to be greatly in favor 

 of the English system of units and tries to show that it is more 

 convenient to use it than the metric system. This question of 

 units has been thoroughly discussed by engineers and scientists 

 for some time in the past, and each system has its own followers. 



The subject matter in the book is arranged in the most logical 

 order, and the practical applications of the theories discussed 

 are clearly shown. 



The problems and examples seem carefully chosen and well 

 worked out and should furnish a guide to students who are be- 

 ginning to study algebra to enable them to develop the process 

 of correct and logical thinking. 



The book will prove valuable to students and teachers and 

 will be a great help for those intending to take examinations 

 in algebra. 



As a whole, the book admirably responds to the purpose for 

 which it is intended, and its use is greatly recommended. 



F. V. Valencia. 



The Application of | Physico-Chemical | Theory to technical processes and | 

 manufacturing methods, | by | Prof. Dr. R. Kremann | (Graz) | 

 Translated from the German by | Harold E. Potts | M. Sc. (Liverpool) 

 I and I edited by Albert Mond, Ph. D. | [ornament] | New York | 

 D. Van Nostrand Company | Twenty-five Park Place | 1915 | Pp. 

 i-xv — 1-212. Cloth, price, $2.50 net. 



"Physical chemistry used to be considered a somewhat theore- 

 tical branch of study, but it has recently developed in such a 

 way as to explain many of the empirical observations of tech- 

 nology and to prove extremely suggestive of many new methods, 

 etc." 



Besides the discussion of theory the author has taken up the 

 special topics of: The ideal efficiency of the steam engine; the 

 gas engine; producer gas; water gas; colloidal solutions; the 

 catalytic action of ferments; the drying of linseed oil; vitrifi- 

 cation and devitrification; the Deacon process; the contact pro- 



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