928 Dr. R. D. Kleeman on Disintegration of an Ion 



It will be seen that the value of the quantity tj, and the/ 

 relative values of Jc 2 and k h are of the same order of 

 magnitude as those obtained in a previous part of this paper. 

 It was found impossible to use equation (2) in the case of 

 C0 2 , because the velocity of the negative ion cluster was 

 found to be greater than proportional to the electric field 

 for the smallest values of a obtainable from Townsend's 

 experiments. 



The Disintegration of Ion Clusters through the Action of 

 the Electric Field. 



Results were obtained which show that an electric field 

 applied to an ionized gas helps to disintegrate the clusters if' 

 of appropriate strength. It is essential in these experiments 

 to be able to prove that the effect is not due to the positive 

 ions producing further ions by collision. Now the bends in 

 the curves connecting the ionization with the electric field 

 for the negative and the positive ions, which indicate the- 

 fields for which a great increase in ionization by collision 

 with increase of field begins to take place, are the further 

 separated the smaller the distance between gauze and plate. 

 The region over which the collision ionization due to positive 

 ions is small in comparison with that due to negative ions 

 thus decreases with this distance. This will appear at once 

 from a consideration of the formula for the collision currents 

 for positive and negative ions given by Townsend. In these 

 experiments the distance between gauze and plate was there- 

 fore changed to half that in the experiments just described,. 

 or made equal to '5 cm. The curve A in fig. 3 shows the 

 currents obtained with the negative ions with C0 2 at a 

 pressure of 1 mm. of mercury plotted against the electric 

 field, and the curve C shows the product of 10 and the 

 logarithms of the currents to the base 10 plotted against the 

 field. The curve B was obtained by plotting the current 

 against the electric field when the field was reversed, the 

 production of new ions by collision being now initiated by 

 the positive ions. The numbers from which the curves have 

 been plotted are given in Table II. The curve D was obtained 

 on plotting the logarithms of the currents calculated in the 

 way described on the supposition that no ion clusters become 

 free on their passage from gauze to plate. The form of the 

 part a b of the curve we have seen indicates that for the 

 corresponding electric fields the ion clusters are principally 

 disintegrated through bombardment by neutral molecules. 

 Since the part b c of the curve lies below the curve C, the 

 increase in current observed is greater than if a constant 



