488 Wellisch and Bronson — Distribution of the Active 



In the last two instances there was, of course, a deposit 

 of activity on the walls of the vessel. 



Other experiments were made with the same object, in some 

 instances large amounts of activity being previously concen- 

 trated on the walls of the vessel so as to increase still further 

 the ionization. The results were of the same nature, viz., to 

 show a small decrease in the amount of activity deposited on 

 the cathode when additional ionization was produced ; the 

 decrease could be accounted for if we adopt the view that the 

 restatoms behave as positive ions, and are subject to increased 

 recombination with the negative ions produced by the appli- 

 cation of the extraneous radiation. 



4. Experiments with Larger Potentials. Air at 1 atmosphere. 



Experiments were next made to ascertain the percentage of 

 the total activity that was deposited on the cathode when larger 

 positive potentials were applied to the case. The result of this 

 set of measurements is given below (Table I), and is exhibited 

 which refers to air at 1 atmosphere ; the 



as a curve in 



fig. 2, 



Fig. 2. 



£100 



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r§ 80 



o 



60 



40 





A 



KUOSMBHE . 





w 





s- 



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f 



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750 



1500 



2250 



3000 3750 4500 



Potential in volts 



method of procedure for determining the points has already 

 been given in section 2. 



It will be seen from an inspection of this curve that the per- 

 centage cathode activity always increased with the applied 

 potential, a result which indicates that there are practically no 

 negative carriers of activity ; all the so-called anode activity to 

 which reference is made by many investigators is due to the 

 diffusion to the walls of the vessel of uncharged restatoms. A 

 slight correction has on this account to be made for the amount of 

 uncharged activity that diffuses to the cathode during the expo- 

 sure ; this correction was made by estimating the relative areas 

 of the exposed surfaces of cathode and case, which were found to 



