PUBLISHER'S PREFACE 



ALTHOUGH the present work was published in France in the year 

 1914 it has not been possible, owing to war conditions, to present 

 an English translation thereof until the present date. 



Owing, however, to the general suspension of such experimental 

 research as this during the war (except in regard to the appli- 

 cation of these principles to the re education of the disabled) 

 the English reader will not find that the value of the book has 

 been in any way affected by the time which has transpired 

 between its first production and its translation. 



As will be seen from his preface, M. Amar has laid special 

 emphasis on the need for the application to the study of the 

 Human Motor of the general principles of Mechanics. He has 

 therefore devoted Book I. to a general exposition thereof. 



The reader who is familiar with the general principles of 

 Mechanics and Thermo-dynamics may therefore be advised to 

 commence his reading at Book II. 



It has not been thought necessary to convert metric measures 

 into their English equivalents, since it is probable that most 

 English workers in this field would themselves employ the C.G.S. 

 System. Full and convenient tables of equivalents and conver- 

 sion factors are, however, here provided. 



G. R. & S., LTD. 



