﻿284 Mr. R. D. Kleeman on the Recombination 



As we pass from one plate towards the other the number 

 of ions moving in the same direction will in general 

 increase with the distance from the plate. Suppose that 

 the lack of saturation observed is due to general recom- 

 bination. Then, if we increase the ionization, the density of 

 the moving ions of each sign becomes greater everywhere, 

 and we increase general recombination, whatever the value 

 of the recombination coefficient, and therefore the lack of 

 saturation. But it has been shown in this paper, and in the 

 paper by Prof. Bragg * and the writer, that the lack of 

 saturation is independent of the density of the ions, when on 

 the whole it is small. 



If the ions are of a very slow moving kind, then the 

 increase in density of the ions of one sign with the distance 

 from the plate from which they are receding, is greater than 

 before, and therefore general recombination as a whole 

 greater. If the observed lack of saturation is due to the 

 existence of slow moving ions, it is caused by greater general 

 recombination taking place, and, therefore, if we increase 

 the ionization we ought to increase the lack of saturation. 

 But since the lack of saturation has been shown to be 

 independent of the density of the ions, it follows that it is 

 also independent of their velocity. That the lack of saturation 

 is independent of the velocity and recombination coefficient 

 of the ions, follows also from the fact that lack of saturation 

 is independent of the depth of chamber. 



In the paper on the recombination of ions by Prof. Bragg 

 and the writer, an experiment of Rutherford's was quoted in 

 support of the initial recombination theory. Rutherford 

 found, in the experiment mentioned, that the ionized gas 

 drawn away from the uranium which ionized it, and treated 

 in a separate vessel, was easier to saturate than when it was 

 in contact with the uranium and ionization going on con- 

 tinuously. 



In a later paper f Prof. Bragg describes an experiment by 

 Mr. Madsen, who found that the current through a mixture 

 of air and ether drawn away from the uranium which ionized 

 it, was still hard to saturate. 



But such an effect may appear quite apart from initial 

 recombination. At the instant a portion of the ionized gas 

 comes under the action of the field, it must contain some ions 

 in the act of undergoing general recombination, and a greater 

 or smaller number of these ions will be separated again, 

 according to the strength of the field. 



It should be observed that the electric field has no further 

 * Loc. cit. f Phil. Mag. May 1906. 



