422 Prof. E. M. "Wellisch : Experiments on 



was assigned in the previous paper is incorrect on account o£ 

 the erroneous assumption which was there made with regard 

 to the diffusion distribution. 



It may not be out o£ place here to draw attention to the 

 fact that nothing has been said with regard to the charge 

 carried by the deposit particle at the moment of formation ; 

 what is here asserted is that the particles are uncharged in 

 ether at the end of their recoil path, even in the presence of 

 electric fields which are easily able to prevent recombination 

 of the gaseous ions. 



It is probable that if the concentration of the emanation 

 were sufficiently great, the deposit particles in ether would 

 form positively and negatively charged aggregates, as has 

 been shown later (Section 5) to occur for the deposit particles 

 in air. 



Distribution of Active Deposit in Air, Hydrogen, and 

 Carbon Dioxide. 



4. A slight correction has to be made for the limiting 

 values of the cathode deposit in air, hydrogen, and carbon 

 dioxide, owing to the fact that in the previous paper the 

 diffusion correction was made on the assumption that the 

 diffusion distribution was proportional to the areas of 

 the exposed surfaces. The experimental values (p), un- 

 corrected for the diffusion of neutral particles, which were 

 obtained for the percentage cathode deposit were as follows : 

 air 89-4, H 2 89*4, C0 2 81*1. 



The corrected values which give the number of positive 

 particles expressed as a percentage of the total number of 

 particles are obtained by evaluating the expression 



200p-2,100 

 179 



These values are : air S8'2, H 2 88% C0 2 78'9. 



The broken curves given in fig. 2 of the previous paper, 

 which exhibit the dependence of the cathode deposit on the 

 amount of emanation when small potentials are applied to the 

 case, w T ould take slightly different positions if the proper 

 diffusion correction were made. The effect of this correction 

 would be to make each activity curve lie still further below 

 the corresponding ionization curve than it actually does in 

 the diagram ; this would bring out with greater emphasis 

 than before the fact that the rate of recombination between 

 the positively charged deposit particles and negative ions is 

 greater than between the positive and negative ions among 

 themselves. Inasmuch as this point is brought out clearly by 



