614 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



At first I studied the effect of increasing the self-induction on the 

 admittance of the mixture of anode and cathode rays to the region C. 



Figure 1. 



The phosphorescence on the screen at the end of the tube was ob- 

 served with a spectrophotometer, and also with a photometer consisting 

 of crossed nichol prisms. 



In Figure 2 the intensity of light is plotted along the axis of Y, 

 and the wave lengths of the circuit along X. The phosphorescence 



appeared suddenly at wave length 380 meters, and increased to a 

 maximum at wave length 620. The curve then continued parallel to 

 the axis of X. In determining the wave lengths I employed the ad- 



