VIII 



THE SMALLEST WORKERS 



IN our studies of the steam engine and gas engine we 

 have been concerned with workers of infinitesimal 

 size. Yet, if we are to believe the reports of the mod- 

 ern investigator, the molecules of steam or of ignited 

 gas are small only in a relative sense, and there is a 

 legion of workers compared with which the molecules 

 are really gigantic in size. These workers are the atoms, 

 and the yet more minute particles of which, according 

 to the most recent theories, they are themselves 

 composed. 



These smallest conceivable particles, the constitu- 

 ents of the atoms, are called electrons. They are a dis- 

 covery of the physicists of the most recent generation. Ac- 

 cording to the newest theories they account for most 

 perhaps for all of the inter-molecular and inter-atomic 

 forces; they are indeed the ultimate repositories of those 

 stores of energy which are known to be contained in all 

 matter. The theories are not quite as fully developed 

 as could be wished, but it would appear that these 

 minutest particles, the electrons, are the essential con- 

 stituents of the familiar yet wonderful carrier of energy 

 which we term electricity. In considering the share of 

 electricity in the world's work, therefore, we shall do 

 well at the outset to put ourselves in touch with recent 



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