[BOYLE] ABSORPTION OF THORIUM EMANATION BY CHARCOAL 145 



caught in a sieve of ten meshes to the inch, III for twenty meshes to 

 the inch, and IV for thirty. It can be seen that as the grain of the 

 charcoal is made smaller the absorption of the emanation by the charcoal 

 is increased. The following facts, taken from Fig. 2 and tabulated, 



(80 



4 6 8 10 



Flow in cc per sec 



11 



illustrate this point. The percentage absorption for any given speed 



is represented by 



the difference between non-absorption and absorption ordinales 



