﻿174 Mr. J. C. Pomeroy on the Charges on 1 hermions 



method is to have the ions moving in a uniform field and 

 then examine the distribution in some particular case. A 

 vertical section of the apparatus used is shown in figure 1. 



The ions given off by the heated strip S pass downward 

 under the action o£ the field and part of them pass through 

 the opening in plate B, which was covered by a grating of 

 fine wire. The stream of ions then opens out so that part 

 fall on the central disk c and the remainder on the ring r, 

 and the ratio of these two quantities Q c /Q r was measured by 

 connecting first one and then both disk and ring to an elec- 

 trometer, when the ratio Q r /Q c is given by 



Qft'Qr op Q,'Q .^.Vj/cv.-i, 



according as the ring r or the disk c is first connected to 



