A HISTORY OF SCIENCE 



fractional machine hitherto in use, the advantage lying 

 in the fact that the current from the galvanic battery 

 could be controlled practically at will, and that the 

 apparatus itself was inexpensive and required com- 

 paratively little attention. These advantages were 

 soon made apparent by the practical application of the 

 electric current in several fields. 



It will be recalled that despite the energetic endeav- 

 ors of such philosophers as Watson, Franklin, Galvani, 

 and many others, the field of practical application of 

 electricity was very limited at the close of the eigh- 

 teenth century. The lightning-rod had come into 

 general use, to be sure, and its value as an invention 

 can hardly be overestimated. But while it was the 

 result of extensive electrical discoveries, and is a most 

 practical instrument, it can hardly be called one that 

 puts electricity to practical use, but simply acts as a 

 means of warding off the evil effects of a natural mani- 

 festation of electricity. The invention, however, had 

 all the effects of a mechanism which turned electricity 

 to practical account. But with the advent of the new 

 kind of electricity the age of practical application be- 

 gan. 



DAVY AND ELECTRIC LIGHT 



Volta's announcement of his pile was scarcely two 

 months old when two Englishmen, Messrs. Nicholson 

 and Carlisle, made the discovery that the current from 

 the galvanic battery had a decided effect upon certain 

 chemicals, among other things decomposing water 

 into its elements, hydrogen and oxygen. On May 7, 

 1800, these investigators arranged the ends of two 



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