﻿in Air and Hydrogen, at Atmospheric Pressure. 181 



to the greatest that it was thought that the strip would stand, 

 and in taking the readings the current was gradually in- 

 creased, and then lessened again to eliminate errors which 

 might creep in from changes in the wire due to heating. 



In the table below are given the differences of potential 

 between the plates B and I which were found necessary to 

 give the same value of Q r /Q c as 200 volts gave with the ioni- 

 zation from radium. The average results obtained from 

 single strips are given, as combined results from different 

 strips would have no meaning, because the same current with 

 a different strip might mean quite a different temperature. 



The numbers given for potential differences are of course 

 inversely proportional to the average charge carried by the 

 ions in question. 



Table II. 



Current. 



P.D. to give constant 

 Qr/Q c - 



Average charge. 



Strip " A " in air. 



12 amp 



14 „ 



16 „ 



18 „ 



Strip " B : ' in air. 

 14 amp 



In Hydrogen. 



12 amp 



14 „ 



ir> „ 



18 „ 



IiaBr in air. 



Pos. 

 205 

 120 

 112 

 108 



193 



203 

 191 

 184 

 112 



200 



Neg. 



114 



106 



no ions. 



180 



172 



90 



200 



Pos, 

 1 



1-7 

 1-8 

 19 



Neir. 



1-8 

 1-9 



1 



no ions 



1 



11 



1-1 



1-1 



1-8 



22 



It is probable also, although this was not tested, that at 

 low pressures in air the same variations might be found. 



A little work was done with positive ions from nichrome, 

 which indicated that practically the same results might be 

 looked for, but the experiments were not satisfactory. It 

 was found impossible with the apparatus at hand to roll the 



