162 The Philippine Journal of Science 1917 



tically rainless months, and once during a period of frequent 

 rains. The results of the two determinations, which are prac- 

 tically identical, indicate that deep-seated springs, such as Sibul 

 Springs, may show surprisingly small seasonal variations in 

 radioactivity. It should be pointed out that Sibul Springs 

 shows a comparatively slight variation in flow throughout the 

 year, so that the inference from the two isolated determinations 

 just discussed is not considered to be at variance with the find- 

 ings of other investigators. Thus Ramsey 10 found a greater 

 emanation content in certain springs during periods of wet 

 weather and great flow, and Steichen 20 observed an increase in 

 activity in certain Bombay hot springs during the dry season, 

 while the flow of water was considerably reduced. As pointed 

 out by the latter writer, local conditions may well account for 

 the differences noted. 



For the sake of completeness we have noted in our data (Table 

 I) all sources of water supply which are popularly considered 

 to have special medicinal virtues. Either popular opinion is a 

 poor guide to the medicinal value of a water, or else the medicinal 

 properties of water are not to any great extent due to radium- 

 emanation content. The waters with perhaps the greatest reputa- 

 tion, namely, Los Banos (12) and Sibul Springs (4 and 5), have 

 relatively high radium-emanation contents, yet many others 

 regarded as highly, such as Marilao (3), Pansol (9 and 10), 

 Santo Tomas (36) and Klondike (72), contain little or no ema- 

 nation. Moreover many waters high in activity, such as Batan- 

 gas (1), Kiangan (66-71), Pagsanjan (19 and 21), and in 

 general, the spring waters near Mount Banajao (13-17), are 

 regarded with entire indifference. 



Although emanation taken into the stomach is probably dif- 

 ferent in effect from that taken into the lungs, the following 

 comparison may be of interest: Assuming that in ordinary 

 respiration the average human being breathes 7 liters of air per 

 minute, or 10.1 cubic meter per day, the emanation content thus 

 brought in contact with the human system is 770 XlO" 12 curies, 

 if the normal emanation content of the air in the Philippines 21 

 be taken as a basis for calculation. Therefore a person would 

 have to drink about three-fourths liter of Sibul Springs water. 



19 Ramsey, R. R., The variation of the emanation content of certain 

 springs, Phil. Mag. (1915), 30, 815-818. 



20 Steichen, A., The variation of the radioactivity of the hot springs at 

 Tuwa, ibid. (1916), 31, 401-403. 



a Wright, J. R., and Smith, O. F., loc. cit. 



