produced by the Corpuscles given out by Radium. 555 



for different deflexions (which are, however, usually very 

 small) is eliminated, and leaks due to faulty insulation are 

 minimized, these leaks helping the leak to be measured for 

 half the time and opposing it for the other half. 



It is of great importance that the P.D. between PP and 

 pp should be sufficient to saturate the gas, i. e., to remove the 

 ions as fast as they are formed. 



In the first two series of observations the current was 

 measured for several different P.D/s, and in the third a P.D. 

 was always applied which was known from the previous 

 observations to be sufficient to produce saturation. The 

 nature of the current-E.M.F. curves may be seen from the 

 results given in Table I. and plotted in fig. 2. 



Fig. 2. 



-5 



-dO 



-25 



















































































1 



o ^ 



3 



4 



5 



6 



7 



8 



9 



I0 























































































I 

































i 



1 



















Table I. 



I 



Pressure. 



P.D. 



Current. 



Lower Plate + . 



Lower Plate — . 



190 



2 



20 

 40 

 60 

 80 

 100 



4-124 



4-15-0 

 4-15-8 

 4-16-1 

 4-16-4 

 4-16-3 



-23-8 



-25-5 

 -250 

 -25-2 

 -25 

 -251 



