xii. ,\, s Wright and Heise: Philippine Waters 163 



or one and one-half liters of Los Banos water, in order to take 

 as much emanation into his system as he ordinarily secures by 

 ordinary daily respiration alone. 



SUMMARY 



The radioactivity of about ninety different Philippine waters, 

 chiefly from springs and flowing wells, has been studied. The 

 highest radium-emanation content encountered in a deep-well 

 water was equivalent to 2100 XlO 12 grams of radium; the 

 highest in a spring water was equivalent to 1300 XlO -12 grams 

 of radium. 



A test for the actual radium content of about twenty typical 

 sources showed that the radioactivity encountered was due to 

 emanation absorbed from materials with which the ground 

 water had been in contact and was not due to dissolved radium 

 salts. One sample of water showed a scarcely detectible trace 

 of activity due to radium salts in solution ; all the others tested 

 gave negative results. 



