Ionization from Heated Platinum. 



181 



recently pointed out that the affinity of gases for electrons is 

 in the following order : — Chlorine, nitric oxide, oxygen, 

 hydrogen, argon, and helium. 



Curve 1, fig. 2 (data for curves of this figure are tabulated 

 in Table III.), shows the relation between the negative 

 currents and the temperatures and was taken after the 

 results given in Curves I. and III. of fig. 1. After heating 



Table III. 





Tenip. ° C. 



After data 



obtained in 



Curves Land II., 



fig. 1. (See 

 Curve 1, fig. 2.) 



After 



first heating 



in Bunsen fiame. 



(See Curve 2, 



fig. 2.) 



After 



second heating 



in Bunsen flame. 



(See Curve 3, 



fig. 2.) 





765 



0-38 









774 



0-58 









7S0 



082 









792 



25 









804 



42 









815 



202 









839 



52-3 



082 



072 





846 





130 







852 





2-50 



1-73 





858 



135 



45 







864 







102 



24 





870 





185 



6-0 





877 









75 



in the Bunsen flame and proceeding in the manner shown in 

 Curves III. and IV., fig. 1, the negative emission was that 

 shown in Curve 2, fig. 2. Following the second heating in 

 the gas-flame Curve 3, fig. 2, was obtained. The relatively 

 large decrease in negative emission and the higher tempera- 

 ture at which the negative currents were detectable in Curve 2 

 as compared with Curve 1, fig. 2, indicates the removal of a 

 considerable portion of the negative electrification between 

 the two stages. Curves 2 and 3 show by comparison a small 

 decrease in negative currents. The positive effects go hand in 

 hand with these changes ; an enormous increase in the positive 

 emission (Curve III., fig. 1) being accompanied by a subse- 

 quent decrease in the negative emission (Curve 2, fig. 2). 

 In a similar manner the small increased positive effect 



