Foundations of the Universe 



would be of small importance in comparison with the control 

 over the inexhaustible stores of internal atomic energy to 

 which its successful accomplishment would inevitably U;ul. 

 It has become a problem, no longer redolent of the evil asso- 

 ciations of the age of alchemy, but one big with the promise 

 of a veritable physical renaissance of the whole world. 



If that "promise" is ever realised, the economic and social 

 face of the world will be transformed. 



Before passing on to the consideration of ether, light, and 

 energy, let us see what new light the discovery of the electron 

 has thrown on the nature and manipulation of electricity. 



WHAT IS ELECTRICITY? 



The Nature of Electricity 



There is at least one manifestation in nature, and so late 

 as twenty years ago it seemed to be one of the most mysterious 

 manifestations of all, which has been in great measure explained 

 by the new discoveries. Already, at the beginning of this cen- 

 tury, we spoke of our "age of electricity," yet there were few 

 things in nature about which we knew less. The "electric cur- 

 rent" rang our bells, drove our trains, lit our rooms, but none 

 knew what the current was. There was a vague idea that it was 

 a sort of fluid that flowed along copper wires as water flows in a 

 pipe. We now suppose that it is a rapid movement of electrons 

 from atom to atom in the wire or wherever the current is. 



Let us try to grasp the principle of the new view of elec- 

 tricity and see how it applies to all the varied electrical 

 phenomena in the world about us. As we saw, the nucleus of an 

 atom of matter consists of positive electricity which holds together 

 a number of electrons, or charges of negative electricity. 1 This 



J The words "positive" and "negative" electricity belong to the days when it was 

 regarded as a fluid. A body overcharged with the fluid was called positive; an under- 

 charged body was called negative. A positively-electrified body is now one whose atoms 

 have lost some of their outlying electrons, so that the positive charge of electricity 

 predominates. The negatively-electrified body is one with more than the normal number 

 of electrons. 



