84 Prof. A. Wehnelt on the Discharge of 



These results are graphically exhibited in fig. 2. 



Fig. 2. 



ISO 



JtC 



12G 



W 



20 

















i 



































\ 

 \ 



























































i 











































































* 









1 















J 























^ 



























1 













































































F i 



















1 



* 



y 



~0~j 















n 







v^ 



Ba 



900 



1000 



H00 1200 1300 



Temperature. 



1500 



On comparing these curves with those obtained by Mr. 0. 

 W. Richardson* for pure platinum, it is found that they 

 possess precisely the same character. An application of the 

 test suggested by Mr. 0. W. Richardson to my results showed 

 that his exponential formula satisfactorily represents the con- 

 nexion between the number of corpuscles emitted and the 

 temperature in the case of metallic oxides also. 



From the much stronger emission of negative ions by the 

 oxides, I concluded that the latter contain more corpuscles 

 per unit of volume than platinum. A calculation of the 

 number contained in unit volume leads, on the other hand — 

 as has recently been shown by Mr. 0. W. Richardson f — to 



* 0. W. Richardson, Proc. Cambr. Phil. Soc. xi. p. 291 (1901). 

 f O. W. Richardson, Jdhrbuch fur Radioaktivitat und JSlektronik, i. 

 p. 313 (1904). 



