34 



Mr. J. J. E. Durack. on Lenard Rays. 



As the apparatus here employed was very convenient for 

 measuring the conductivity at different distances from the 

 window, observations were made to find the rate of decrease 

 in the ionization with increasing distance. 



Readings of the leak produced in 10 seconds were taken at 

 different distances, the discharge-tube pressure being kept 

 constant and such as to produce the maximum leak. 



Cubve I. 



, ■ — 



< 



\ () , 



2 3 4 5 6 7 



Distance, mm. 



9 10 11 12 



The following table gives the results of these readings. 

 Distances are measured from the window to the inside edge 

 of the end of the cylinder. 



