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SUMMARY OF CURRENT RESEARCHES RELATING TO 



Method B. — This consists in reducing the intensity of the stronger 

 light by an absorbing medium. For this purpose the following 



Fig. 13. 



arrangement is adopted. It is in principle somewhat similar to the 

 " colorimeter " often used in chemical analysis, and is an adaptation of 

 the method the author recently patented for determining the "light- 



