174 THE NEW WORLD OF SCIENCE 



the industries. ^ This is certainly true of gas masks, and the 

 absorbents in gas masks can be used for a diversity of purposes. 

 The charcoal especially is an extraordinary absorbent or cata- 

 lyst for a variety of purposes. Analytical chemistry received 

 an impetus. It is undoubtedly true that never before was so 

 much work done in so short a space of time on the refinement of 

 analytical methods, necessary in order to measure gases in so 

 great dilution as one part in ten million or twenty million. The 

 Friedel and Crafts reaction was successfully put in operation 

 on a larger scale than ever before in this country. For every 

 offense problem there was a defense one, and the defense prob- 

 lems worked out for protection of American soldiers will bear 

 fruit in protecting American workers in industries." 



