on the Ionization produced in Gases by Rontgen Rays. 193 



the plate adjustable so that it might be removed in order to gain 

 access to the interior of the cylinder when desired. 



E and E are two parallel brass plates acting as electrodes 

 between which the gas is ionized and between which the rate 

 of leak is measured. E is surrounded by a guard-ring connected 

 to earth. These plates are supported by brass rods H and H' , 

 which pass through heavy ebonite corks fitting tightly into the 



Girth 



Fig. 2. 



brass tubes D and D'. The joints between the ebonite and the 

 brass are made gas-tight by means of heavy rubber corks bored to 

 fit tightly over the ebonite and the brass and then bound round 



