THE ELECTRICAL NATURE OF MATTER. 185 



of matter in a body depends on the speed with which an 

 electric charge moves, is difficult to grasp concretely; for 

 we are accustomed to think that the quantity of any given 

 object is invariable. We may, however, obtain a concrete 

 representation of the idea by considering the analogical 

 case of a sphere moving through a frictionless liquid. In 

 such a case, when the sphere moves, it sots the liquid 

 around it moving with a velocity proportioned to its own, 

 so that the sphere is accompanied by a definite volume of 

 the liquid. This volume is one-half the volume of the 

 sphere and the sphere, therefore, behaves as though its 

 mass were increased by that amount. In the case of a 

 cylinder moving at right angles to its length, the mass of 

 the cylinder is increased by the mass of an equal volume 

 of the liquid. Now the cylinder in our case is the electric 

 charge and the frictionless liquid is the ether. The electric 

 charge possesses no mass at all, and the total mass, there- 

 fore, is due to the bound ether carried along by the charge 

 ir_ its motion, the total amount of "the bound ether de- 

 pending on the velocity of the charge. On this view of 

 "the electronic theory of matter," all mass is the mass of 

 the ether, all momentum, whether electrical or mechanical, 

 the momentum of the ether, and all kinetic energy the 

 kinetic energy of the ether. 



The electronic theory of matter may be used, as we 1, 

 to account for certain properties of electricity. Corpuscles, 

 used in this connection, are generally given another name; 

 they are called electrons. Since we have used the word 

 corpuscles throughout we shall continue to use it in this 

 connection, remembering, however, that the two words, 

 corpuscle and electron, stand for the same thing precisely. 

 An electric current, for example, is easily explained on the 

 corpuscular theory. Electricity may be conducted through 



