64 



The Philippine Journal of Science 



1914 



d^ the electroscope reading corresponding to the emanation from 

 M' gram of radium. 



Solving the equation for M, we get 



„ M'XTd 



Eve arrives at the same result by a method somewhat more 

 mathematical. Satterly neglected the decay of the emanation 

 from the air during the time of the exposure, which introduces 

 a slight error in his calculations, the error being almost negligible 

 for short runs, but considerable for exposures of twenty hours 

 or longer. 



The results of observations on the radium-emanation content 

 of the atmosphere extending over a period of about eight months 

 are given in Table VI, 



Table VI. — Radium-emanation content of the atmosphere of Manila. 



Date. 



Radium 

 in solu- 

 tion in 

 grams X 



109. 



Rate of 

 flow of air 

 stream in 

 liters per 



minute. 



Duration 

 of expo- 

 sure. 



Electro- ' Electro- 

 scope read- scope read- 

 ing in ing due to 

 divisions emanation 

 per minute from given 

 due to , volume of 

 emanation air and 

 in given from stand- 

 volume of ard solu- 

 air. tion. 



! Emanation 

 , Electro i^Per cub^^ 



n^duT,^- ex^Pressed 

 emanation j: ,_. 



10 1«. 



1912. 



July 26 



Aug. 3 



Sept. 12.. 



3.140 

 3.140 

 3.140 



0.33 

 0.33 

 0.33 

 0.33 

 0.33 

 0.50 

 0.50 



0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 

 0.50 



Hrs. 

 20.0 

 21.0 

 20.0 

 20.0 

 20.0 

 20.0 

 20.0 



20.0 



20.0 



10.0 



15.0 



5.0 



5.0 



20.5 



20.0 



5.0 



20.0 



20.0 



20.0 



20.0 



15.0 



0.139 

 0.110 

 0.450 



2.258 

 1.650 

 3.668 



2.009 

 1.540 

 3.218 

 3.108 



81.06 



84.10 



164.60 



85.62 



Sept. 18 - 



3.140 

 3.140 



0.226 3.334 

 0.326 i 4.932 



Sept. 23 



4.590 1 100.50 1 



Dec. 16..._ 



Dec. 23 _. 



1913. 



Jan. 2 



Jan. 8 



Jan. 16 



Jan. 20..-_ 



Jan. 22 



Jan. 24 



Jan. 26.__ 



Jan. 30 



Feb. 4 



Feb. 10 



Feb. 12 



0.628 

 0.628 



0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 

 0.628 



0.531 

 0.774 



0.526 

 0.706 

 0.136 

 0.864 

 0.096 

 0.096 

 0.282 

 0.285 

 0.053 

 0.676 

 0.472 



1.285 

 1.658 



1.267 

 1.437 

 0.533 

 1.521 

 0.314 

 0.319 

 0.982 

 0.593 

 0.173 

 1.062 

 1.354 



0.754 

 0.884 



0.741 

 0.731 

 0.399 

 0.657 

 0.218 

 0.223 

 0.700 

 0.308 

 0.120 

 0.546 

 0.8S2 



110. 60 

 137. 50 



110.40 



151. 60 

 53.50 



164.00 

 69.20 

 67.60 

 63.45 



145.00 

 69.39 



194.40 

 84.03 



Feb. 17 -_ 



0.581 



1. 541 0. 960 95. 02 



Mar. 11 



0.491 

 0.352 



1.495 1.004 76.78 



Mar. 18 



0.628 



1. 039 0. 687 



80.40 



Mean . . . 





104.23 



: 1 1 1 1 ! 





The mean of all the results obtained during the period from 

 July to February inclusive is 104.23 XlO^^^ gram. This value 



