410 



Mr Rutherford, The Discharge of 



[Feb. 21, 



the table below shows, which gives the rate of leak at different 

 distances from the base plate. 



9 turns of the screw is approximately the shortest distance 

 between the plates for which the loss of charge is negligible, and 

 the numbers show how rapid is the decrease of deflection between 

 7 and 9 turns. 



Let u = velocity of the carrier for a potential gradient of one 

 volt per cm. 



d = shortest distance between the plates for which the 

 leak of AB is zero. 



T = time of complete alternation of the transformer. 



It is assumed that the E.m.f. at any time of the alternation is 

 given by i^ sin 27r ™ , where E is the maximum value of the 

 alternating E.M.F. 



The distance dx traversed by an ion in the time dt is given by 



T? t 



dx = ~t° . sin 2tt ™ . u . dt. 



d 



T 



Now the distance passed over by the carriers which first set 



T 



out is equal to d in the time -~ . 



