^4/?= at different Temperatures and Pressures. 235 



cylinder is charoeil to 280 volts. The cylinder was main- 

 tained at this potential in all the temperature experiments, 



Fig. 2. 



«=; 



Am 



wteNCyuNOER aI ELetmob 



but 1000 volts were used in some of the experiments on 

 pressure. 



In taking the observations the current through the gas 

 was measured and the capacity o£ the electrometer and con- 

 nexions determined. The cylinder was then heated until the 

 temperature became steady and the current again measured. 

 The results of a set of observations are given in the following 

 table. A number of readings vv^ere taken at each tempera- 

 ture and the average is given. Many more observations were 

 taken but they were all similar to the set given. 



Ionization at different temperatures. 



Current between 



Temp. Cvlinder and Electrode. 



20° C. ' 2-6x10-^ 



195 „ 2-7 „ 



230 „ 2-8 „ 



370 „ 2-83 „ 



410 „ 2-7 „ 



460 „ 3-0 „ 



590 1+^'^ " 



" I -4-8 ,, 



These results are plotted in tig. 3, where the abscissae 



Fiof. 3. 



'-TT-^ 



TSMPtfiA rui9£ 



represent the temperatures and the ordinates the current in 

 E.S. units. 



It will be seen from the above that the ionization varied 



