the Method of its Transmission. 



99 



in a stronger electric field in one half alternation than in the 

 other. A carrier consequently moves over unequal distances 

 during the two half alternations, since the velocity o£ the 

 carrier is proportional to the strength o£ the electric field in 

 which it moves. It follows from this that the excited radio- 

 activity will be unequally distributed over the two electrodes. 

 If the frequency of alternation is sufficiently great, only the 

 positive carriers within a certain small distance of one plate 

 can be conveyed to it, and the rest, in the course of several 

 succeeding alternations, are carried to the other plate. 



Suppose A and B (fig. 1) are two parallel plates to be 



shM-J 



made radioactive. The emanation is supposed to be uniformly 

 distributed between them. When B is negatively charged 

 suppose the P. D. between the plates is E — E l5 when B is 

 positive the P. D. is E + E,. 



Let d = distance between the plates, 

 T = time of a half alternation, 

 p = ratio of the excited radioactivity on the plate B to 



the sum of radioactivity on the plates A and B. 

 K = velocity of the positive carriers for unit-potential- 

 gradient 

 On the assumption that the electric field between the plates 

 is uniform,- and that the velocity of the carrier is pro- 

 portional to the electric field, the velocity of the positive 

 carrier towards B is 



E — E : _ 



d ' ' 

 and in the course of the next half alternation 



towards the plate A, 



d 

 H2 



