74 The Philippine Journal of Science isi* 



meter of the atmosphere of Mount Pauai is 24.13x10"^^ gram. 

 If we take into account the fact that bubbling air through the 

 cool standard solution does not remove the emanation as rapidly 

 as it is formed, then the above result should be multiplied by 

 a factor somewhat less than unity. If we assume that this 

 factor is approximately the same as that found under similar 

 conditions in Manila, then it will have a numerical value of 

 0.792. Multiplying by this factor reduces the mean value to 

 19.11 Xl0~^2 gram per cubic meter. The assumption that the 

 reduction factor will be the same for the two different localities 

 may, however, be unjustifiable since both the air temperature 

 and the atmospheric pressure are considerably different for 

 the two places. The lower temperature would tend to decrease 

 the reduction factor, while the decrease in pressure would 

 probably have the opposite effect. It is to be regretted that the 

 time at our disposal did not permit us to make any deter- 

 minations of this factor at the higher altitude. 



The ratio of the mean values of the radium-emanation content 

 for Manila and Mount Pauai is approximately 4 to 1. The 

 maximum value obtained on Mount Pauai is somewhat less than 

 the minimum value obtained thus far for Manila. Since the 

 amount of radium emanation in the atmosphere of any given 

 locality undoubtedly varies between fairly wide limits with the 

 variation in meteorological conditions, it is hardly to be expected 

 that the same relation would exist for observations extending 

 over a long period of time. But the values obtained at the 

 elevation of 2,460 meters are so consistently lower than those 

 found for Manila, which is practically at sea level, that there 

 seems to be small chance to doubt that the radium-emanation 

 content is lower for the higher altitudes. 



Although the observations on Mount Pauai only extended over 

 a period of about four weeks, nevertheless, they were taken 

 under a great variety of meteorological conditions. The weather 

 during the four weeks embraced the three following distinct 

 types: (1) Bright, with exceptionally clear atmosphere; (2) 

 cloudy, with light afternoon showers; and (3) typhoon, with 

 a heavy downpour of rain. Each distinct type extended over 

 a period of several days, so that observations taken during any 

 given period should be fairly typical for such conditions. The 

 variations of the radium-emanation content with the meteorolog- 

 ical conditions are shown in Table X. 



