438 Mr, S. Ratner on the Distribution of the Active 



cathode. After exposure, tlie sheets of aluminium foil were 

 removed and their activities measured in the usual way. 

 Under these conditions the electric wind is directed during 

 the exposure from the active plate towards the inactive, and, 

 as was to be expected, almost the whole activity was found 

 in these experiments to be concentrated on the aluminium foil 

 covering the inactive plate. Thus, with the active plate a» 

 a cathode the anode activity was found in different expe- 

 riments to be 10 times or even 20 times as large as the 

 cathode activity. 



It is worth mentioning a few experiments undertaken for 

 the sake of checking the results. First, when the thickness of 

 the aluminium foil covering the active plate was made large 

 enough to absorb completely the a rays of radium 0, the active 

 deposit was found to be distributed between the electrodes 

 exactly as in the absence of an additional source of ionization 

 inside the vessel. Further, when both of the electrodes were 

 made strong sources of ionization before the exposure, the 

 activity was uniformly distributed between the sheets of 

 aluminium covering the plates. 



Table II. represents the results of a series of experiments 

 described in this chapter. These experiments were carried 

 out in course of a few hours, so that the quantity of emanation 

 in the vessel did not vary appreciably from one experiment 

 to another, and was of the order of *1 inillicurie. The 

 activities are given in arbitrary units, the cathode activity 

 under ordinary conditions being taken as 100. Attention 

 may be drawn to the fact that the sum of activities on the 

 anode and the cathode varies in different experiments within 

 comparatively small limits. 



Table II. 



No additional source of ionization inside the vessel... 



Source of ionization in the middle of the vessel 



Source of ionization at the anode 



Source of ionization at the cathode 



Source of ionization at the cathode covered with thick 

 aluminium foil ( - 05 mm.) 



Cathode 



Anode 



activity. 



activity. 



100 



14 j 



52 



56 



82 



6 



8 



94 



90 



lfi 



1 



Other experiments made without an additional source of 

 ionization, and with large quantities of emanation varying 

 from 1 to 10 millicuries have shown that the anode activity 



