﻿432 Notices respecting New Boohs. 



to illustrate the methods of scientific enquiry by explaining their 

 application to problems in various departments of research. The 

 course consisted of the nine lectures embodied in the volume 

 before us. The first two are of a general nature, " Scientific 

 Method as a Mental Operation," by Professor T. Case,- and " On 

 Some Aspects of the Scientific Method," by Professor Crotch. The 

 remaining lectures serve as illustrations of the working of scientific 

 methods in connexion with various actual problems. Professor 

 Sherrington writes on " Physiology ; its Scope and Method"; Pro- 

 fessor Weldon on "Inheritance in Animals and Plants"; Mr. 

 McDougall on "Psycho-Physical Method"; Dr. Eison on "The 

 Evolution of Double Stars"; Sir Richard Temple on "Anthro- 

 pology : The Evolution of Currency and Coinage "; Professor 

 Elinders Petrie on "Archaeological Evidence'"'; and the General 

 Editor on " Scientific Method as Applied to History." It will be 

 seen that a fairly large number of different departments of scien- 

 tific enquiry" are represented. The work is intended for the general 

 reader, and the interesting manner in which most of the problems 

 are dealt with cannot fail to render the book highly attractive to 

 the mass of the well-educated public. 



Moteurs a Collecteur a Oourants Alter natifs. Par le Dr. E. 

 Niethammek, Professeur a l'Ecole Technique Superieure de 

 Briinn (Autriche). Paris : edite par " L'Eclairage Electrique." 

 1906. Pp. 132. 

 Eew subjects have, within the last three years, attracted more 

 attention or excited keener interest in electrotechnical circles than 

 the single-phase commutator motor, whose advent at a time when 

 the problem of main-line electric traction was being discussed opened 

 up new possibilities of development. The unremitting efforts of 

 all the large manufacturing companies to perfect the single-phase 

 motor afford ample testimony to the importance attached to the 

 solution of this problem. The monograph under review comes at 

 an opportune moment, and will be welcomed by all who have 

 been following the evolution of the commutator motor. Although 

 the author includes in his treatment polyphase as well as single- 

 phase motors, the former type is of far less technical importance, 

 nor is it likely to find any extended use in the future. Much 

 of the matter included in the present monograph has already 

 made its appearance in the form of articles in various technical 

 periodicals, but most readers w T .ill be glad to have the author's 

 contributions to this subject arranged systematically in the form of 

 a monograph. The booklet is divided into three chapters. In the 

 first, the author deals with generalities, including a brief historical 

 sketch. The second chapter is devoted to the theory of commu- 

 tation, and the construction of exact diagrams to represent the 

 behaviour of the motor. The concluding chapter contains de- 

 scriptions of leading types of single-phase commutator motors, 

 and a useful outline of the principles underlying the design of 

 such motors. ' 



