600 ELECTRICAL LIMITS. 



io 5 .io 8 C.G.S. units. With such machines, we shall have, in 

 electrostatic units, 





10"'. 10 10 



13 



3 

 which gives virtually o- = . 



If we assume d=io and e=i, the electromagnetic intensity 

 of the current will be 



u.-zoo u 



As a volt in a circuit of n ohms, gives a current of strength 



r= C.G.S. , 



ion 



it will be seen that in order to have the same current the band 

 must move with a velocity, 



io 7 100000 



metres. 



It must be observed that the current I, produced by the 

 motion of an electrical body, is far more difficult to observe than 

 that of an ordinary electrical cell, since it must act directly on 

 the needle, and without any effect of multiplication. 



Rowland has proved experimentally that the rotation of an 

 electrified disc produces a sensible effect on a magnetised needle, 

 and that the action is of the same order as that which would be 

 given by the preceding considerations. 



