vi PREFACE 



natural sciences and of their related technologies. Complete- 

 ness of treatment within the scope of such a volume as was 

 proposed was impracticable because of the magnitude and 

 diversity of scientific service. It is appropriate to state also 

 that because of the impracticability of mentioning more than a 

 small percentage of those who deserve recognition, no attempt 

 has been made by most contributors to indicate the credit and 

 responsibility of individuals. 



It has been the primary, if not the single, purpose of the 

 several writers to offer to the lay reader an untechnical account 

 of the nature of certain methods and their practical relations 

 to military problems. The editor, and doubtless every con- 

 tributor, has held clearly in mind the importance of acquaint- 

 ing the public with scientific progress and with typical ex- 

 amples of the dependence of industrial advances upon the de- 

 velopment of science. 



THE EDITOR. 



