16 ELECTRIC INERTIA [CH, n. 



If, however, the atomic charge were concentrated 

 into a sphere of dimension 10~ 13 centimetre, its 

 potential would be 1000 electrostatic units, or 

 300,000 volts; its energy would then be 10~ 7 erg, 

 and its inertia 10 ~ 28 gramme, or about YTHJIT f the 

 mass of a hydrogen atom. 



Summary. 



All this is a preliminary statement of undeniable 

 fact : that is to say of fact which follows from the 

 received and established theory of Electricity, 

 whether such things as electrons have ever been 

 found to exist or not. 



All that we have stated is true of an ordinary 

 charge on any ordinary sphere which can be made 

 to move by mechanical force applied to it. 



It gives us the phenomena 



of electrostatics when at rest, 

 of magnetism when in motion, 

 of radiation when its motion is altered ; 

 and it incidentally, by reason of the known laws of 

 electromagnetic induction, exhibits a kind of imitation 

 inertia, and in that way simulates the possession of 

 the most fundamental property of matter. > 



I will add a few more closely connected assertions, 

 for later application : 



Apply a sufficiently violent E.M.F. to a charged 

 sphere, and the charge may be wrenched off it. 



Insert an obstacle in the path of a violently moving 

 charged sphere, so as to stop it mechanically with 

 sufficient suddenness, and again it is possible for the 

 charge, or something like it, to be jerked off it and 

 passed on. But to do this the speed of the material 

 sphere, as well as the suddenness of stoppage, must be 



