THE SMALLEST WORKERS 



THEORIES OF ELECTRICAL ACTION 



But all this, of course, leaves quite untouched the 

 question of the origin of the electrons themselves. 

 That these go hurtling from one plate or pole of the bat- 

 tery to the other, along the wire, we can understand at 

 least as a working theory; that, furthermore, the elec- 

 trons have their origin either in the metal plates or in 

 the liquid that connects them, seems equally obvious; 

 but how shall we account for their development? It 

 is here that the chemist with his atomic theory of matter 

 comes to our aid. He assures us that all matter consists 

 in the last analysis of excessively minute particles, 

 and that these particles are perpetually in motion. 

 They unite with one another to form so-called molecules, 

 but they are perpetually breaking away from such 

 unions, even though they re-establish them again. Such 

 activities of the atoms take place even in solids, but they 

 are greatly enhanced when any substance passes from 

 the solid into the liquid state. 



When, for example, a lump of salt is dissolved in 

 water, the atoms of sodium and of chlorine which 

 joined together make up the molecules of salt are held 

 in much looser bondage than they were while the salt 

 was in a dry or crystalline form. Could we magnify 

 the infinitesimal particles sufficiently to make them 

 visible we should probably see large numbers of the 

 molecules being dissociated, the liberated atoms mov- 

 ing about freely for an instant and then reuniting with 

 other atoms. Thus at any given instant our solution of 

 salt would contain numerous free atoms of sodium and 



