102 ROYAL SOCIETY OF CANADA 
In the above we have discussed, and deduced mathematically, the 
effect on the ionization current in the testing vessel of 
(1) the speed of the air current carrying the emanation, 
(2) the volume of the testing vessel and that of the conducting 
tubes, 
15 
JONIZATION CURRENT, x 436 5» /0 FOR AMPS. 




° 4 -8 12. 16 2.0 24 
FLOW IN CC. PER SEC. 
FACE Q. 
(3) an absorbing substance, and 
(4) the quantity (volume) of the absorbing substance. 
The curves and tables already given, and those which follow, show 
the results of experiments on these points and indicate to what extent 
experiment agrees with the theory. 
As a test between the actual values obtained by experiment and 
those we should expect from the theory, we have the following: 
In the case of .31 gms. of charcoal, suppose that v,, is the volume of 
charcoal, and J,, the ionization current in the testing vessel ; similarly in 
the cases of 1.61 and 5.86 gms., let u,, J,, and u,, J;, be the corresponding 
volumes and ionization currents. 
