218 Mr, M. Ishino on Velocity of Secondary Cathode Bays 



the atoms in air is nearly independent of: the energy of the 

 primary rays. This result agrees with those obtained for 

 8 rays from a metallic plate, and with that obtained for the 

 secondary rays from gas. 



The mean values of the corrected currents for each value 

 of v were calculated. These are given in the last column 

 in Table III. The mean values may be taken as giving the 

 most probably true distribution of the velocities. These are 



Fig. 5. 



'Potential Difference in Volts 



plotted in curve I., fig. 5. It is clearly seen that corpuscles, 

 whose velocities are very large up to 1000 volts, exist in 

 the secondary rays. This result does not agree with that 

 obtained by Sir J. J. Thomson in the case of slow primary 

 cathode rays (§1). It is noticeable that the number of 

 the secondary corpuscles whose energies are greater than 

 40 volts is only about 8"3 per cent, of the total number of 

 the secondary corpuscles. The fact that a small fraction 

 of the secondary cathode rays have large velocities agrees 

 with Bumstead's result obtained in the case of a rays. 



The curve I., fig. 5, resembles a hyperbolic curve over the 



