A HISTORY OF SCIENCE 



elaborations and discoveries by Ampere, Volta, and 

 Henry, and with the invention of Daniell's cell, the 

 way was laid for putting electricity to practical use. 

 Soon followed the invention and perfection of the 

 electro-magnetic telegraph and a host of other but 

 little less important devices. 



FARADAY AND ELECTRO-MAGNETIC INDUCTION 



With these great discoveries and inventions at hand, 

 electricity became no longer a toy or a "plaything for 

 philosophers," but of enormous and growing impor- 

 tance commercially. Still, electricity generated by 

 chemical action, even in a very perfect cell, was both 

 feeble and expensive, and, withal, only applicable in a 

 comparatively limited field. Another important scien- 

 tific discovery was necessary before such things as 

 electric traction and electric lighting on a large scale 

 were to become possible; but that discovery was soon 

 made by Sir Michael Faraday. 



Faraday, the son of a blacksmith and a bookbinder 

 by trade, had interested Sir Humphry Davy by his 

 admirable notes on four of Davy's lectures, which he 

 had been able to attend. Although advised by the 

 great scientist to "stick to his bookbinding" rather 

 than enter the field of science, Faraday became, at 

 twenty-two years of age, Davy's assistant in the Royal 

 Institution. There, for several years, he devoted all 

 his spare hours- to scientific investigations and experi- 

 ments, perfecting himself in scientific technique. 



A few years later he became interested, like all the 

 scientists of the time, in Arago's experiment of rotat- 

 ing a copper disk underneath a suspended compass- 



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