THE SMALLEST WORKERS 



ity in motion traverses chiefly the surface of the conduc- 

 tor, and it came to be believed that the essential feature 

 of the " current" consists of a condition of strain or 

 stress in the ether surrounding a conductor, rather than 

 of any change in the conductor itself. This idea, which 

 is still considered valid, has the merit of doing away with 

 the thought of action at a distance the idea that was so 

 repugnant to the mind of Faraday. 



So far so good. But what determines the ether strain ? 

 There is surely something that is not matter and is not 

 ether. What is this something? The efforts of many 

 of the most distinguished experimenters have in recent 

 years been directed toward the solution of that ques- 

 tion; and these efforts, thanks to the new methods and 

 new discoveries, have met with a considerable measure 

 of success. I must not attempt here to follow out the 

 channels of discovery, but must content myself with 

 stating briefly the results. We shall have occasion to 

 consider some further details as to the methods in a 

 later chapter. 



Briefly, then, it is now generally accepted, at least as 

 a working hypothesis, that every atom of matter be it 

 oxygen, hydrogen, gold, iron, or what not carries a 

 charge of electricity, which is probably responsible for 

 all the phenomena that the atom manifests. This 

 charge of electricity may be positive or negative, or it 

 may be neutral, by which is meant that the positive and 

 negative charges may just balance. If the positive 

 charge has definite carriers, these are unknown except in 

 association with the atom itself; but the negative charge, 

 on the other hand, is carried by minute particles to 



