Ultra- Violet Liylit from the Mercury Arc, 403 



leak from the surface P being the same for both sources of 

 light. It is seen that the electrons are on the whole con- 

 siderably slower when produced by the light from the 



Fie. 5. 



Qnsi/ntita 





























\r 



X 



CL^bO 



























\ 



\ 

























I 



i 



T 



\ 



\ 





<u>h 



CUU} 



& 













f 



/ 





\ 





\ 

















1 





/ 





\ 



\ 



\ 

















1 



/ 









\ 



















1 



„-i , 



t 









\ 



_®_ 





V 



— «- 







mercury arc than when produced by the light from the 

 hydrogen discharge. The result of the superposition 

 experiment is given in the following table. 



Table III. 



H : effect due to H 2 discharge alone. 



A : ,, „ Hg arc alone. 



H-fA (add.) : sum of two previous results. 



H+ A (exp.) : effect due to H 2 discharge and Hg arc superposed. 



Velocity of electrons. 



H. 



A. 



H-fA (add.). 



H+A(exp.). 



6-33xl0 7 cm./sec. 



34-3 



11-8 



461 



4Cv3 



7-38 „ „ 



26-6 



1-8 



28-4 



28-1 



8-44 „ „ 



156 







156 



162 



9-49 



8-4 







8-4 



8-9 



105 



2-8 







2-8 



3'2 



The last two columns agree within the limits of experi- 

 mental error. 



