EMANATIONS. 121 



can be measured by an electroscope and the figures stated 

 above put to the test. This was done, and it was discovered 

 as a matter of fact that the amount of emanation stored in 

 the solid was 477,000 times greater than the amount after- 

 wards developed per second. The agreement between theory 

 and experiment is remarkable and the experiment shows 

 just how accurately it is possible to predict the results of ex- 

 periments in radio-activity. 



