[BOYLE] ABSORPTION OF THORIUM EMANATION BY CHARCOAL 1§1 



Wood Charcoal. 



* Practically. 



Conclusion. 



To conclude, it may be said that the amount of absorption of thorium 

 emanation by means of charcoal, 



(1) depends on the nature of the charcoal used, being greatest for 

 oocoanut, intermediate for animal, and least for wood charcoal ; 



(2) is increased by increasing the charcoal absorbing surface; 



(3) depends on the temperature, following the law for ordinary 

 gases, viz., that a lowering of the temperature of the charcoal 

 causes an increase, and a raising of the temperature a decrease 

 in the amount of absorption, a curve of absorptive power on a 

 temperature base approaching the temperature base in an 

 asymptotic fashion ; 



and (4) is increased by decreasing the velocity of the gas current which 

 conducts the emanation through the charcoal, the absorption 

 being greatest at the slowest possible speeds. 



