Mabch 19, 1915] 



SCIENCE 



431 



tory and discusses the applications of psycBol- 

 ogy to science and art. He indicates the line 

 of demarcation between psychology and the 

 human sciences as follows : The understanding 

 of mental operations is valuable in the study 

 of history, sociology, etc., but the interpre- 

 tation of the subject-matter in each case be- 

 longs to the special science and not to psy- 

 chology. In his closing chapters the author 

 considers the applications of psychological data 

 and methods to education, law, economics, 

 medicine and culture. To this applied field 

 he gives the name psychotechnics. These 

 chapters offer a most interesting presentation 

 of the recent progress in applied psychology, 

 a line of development which seems likely to 

 bring about a closer connection between psy- 

 chology and the professions. 



Whether or not the reader agrees with Pro- 

 fessor Miinsterberg's fundamental positions, 

 he will find the present work most stimulating 

 and suggestive. 



Howard C. Warren 



Princeton University 



Design of Polyphase Generators and Motors. 



By Henry M. Hobaet. McGraw-Hill Book 



Company. 



In " Design of Polyphase Generators and 

 Motors," Mr. Hobart takes up the design of a 

 simple three-phase generator and an induc- 

 tion motor from the standpoint of a design- 

 ing engineer. This occupies the major por- 

 tion of the book, but there are in addition two 

 chapters devoted to a comparison of syn- 

 chronous motors and induction motors and to 

 the induction generator. Much useful in- 

 formation and many valuable tables compiled 

 from empirical data obtained from existing 

 machines are included. 



The book follows the plan, outlined by the 

 author in its preface, of taking up immedi- 

 ately without any preliminary discussion the 

 design of a three-phase generator of definite 

 rating, introducing the principles involved 

 when required as the design progresses. In 

 addition to the design of a three-phase gen- 

 erator, the design of a polyphase induction 

 motor is also considered. The book should be 

 valuable to the young designer who has a fair 



Iniowledge of the principles underlying opera- 

 tion and design of electrical machinery. 



It is to be regretted that a portion of the 

 book is not devoted to a simple analytical 

 study of the effect on the operating charac- 

 teristics of machines of modifying their dimen- 

 sions and windings in order that the young 

 designer might learn to analyze existing de- 

 signs and to be able to judge the fitness of 

 any particular design for a definite class of 

 service. 



Two appendices give a full bibliography of 

 the papers dealing with polyphase generators 

 and motors which have been printed in the 

 Proceedings of the American Institute of 

 Electrical Engineers and in the Journal of 

 the British Institute of Electrical Engineers. 



Ealph E. Lawrence 



Synchronous Motors and Converters. By 

 Andre Blondel. Translated from the 

 French by C. O. Mailloux. McGraw Hill 

 Book Co. 1913. 



" Synchronous Motors and Converters " is 

 a translation of the admirable little book by 

 Andre Blondel entitled "Moteurs Synchrone 

 a Currents Alternatifs." Several chapters 

 have been added to the translation in order to 

 increase the scope of the book and to bring it 

 up to date. The translation is divided into 

 three parts. Part I. is a translation of the 

 original book with one chapter added by Pro- 

 fessor C. A. Adams, of Harvard University. 

 Part II. relates to Rotary Converters and is 

 made of new material by Professor Blondel 

 and a translation of papers presented by him 

 at the Paris Congress in 1900. Professor 

 Adams has also added a chapter to this sec- 

 tion relating to the split-pole converter. Part 

 III. contains reprints of papers presented by 

 Professor Blondel at the St. Louis Electrical 

 Congress in 1904, relating to his " two reac- 

 tion " method of treating the armature reac- 

 tion of alternators. 



The first part of the book takes up the gen- 

 eral principles of synchronous motors and a 

 study of their operation under different con- 

 ditions, and is particularly valuable in giving 

 the development of well-known Blondel hi- 



