298 



Prof. Richardson and Lieut. Bazzoni on the 



1*8 ampere and zero effect at 2*0 amperes, radiation must 

 be present between X 425 and X 500, as reference to fig. 4 will 

 show. As a matter of fact definite effects were obtained at 

 1*9 ampere, and irregular traces of an effect at 2 amperes, 



Fig. 6 A. 



Mm. in 



30 sec. 



40 



O -Z -4 -6 



VQ \>Z 1-4 1-6 1*8 2-0 

 <- Amperes 



Scale for A min and v mm> as on fig. 6. 



which localizes the limiting frequency close to X 425. The 

 limiting frequency, the shape of the curves, and the position 

 of the maximum are seen not to be functions of the driving- 

 potentials on the electrons nor, with certain restrictions, of 



