134 ELECTRICITY. [Lesson XXI. 



the ox idizement of metals while under Voltaic in- 

 fluence, concluded it to be a chemical phenomenon 

 merely. In this year, Volta announced his dis- 

 covery of the Galvanic pile, formed by plates of 

 two different metals, as zinc and silver, disposed 

 alternately with moistened pasteboard between 

 them. By connecting the ends of the pile by 

 the hands, he obtained a strong shock, and pro- 

 duced many curious experiments. Mr. Nicholson, 

 in the same year, employed much of his ingenuity 

 in examining these phaenomena, and devoted a 

 considerable portion of his Journal to their investi- 

 gation. By making a tube of water form part of 

 the line connecting the two ends of the pile, he. 

 found, from the wire passing into the water from 

 the silver end, hydrogen separated; whilst the 

 other, if an oxidable metal, became oxidized, but, 

 if platina, he found oxygen was evolved. Thug 

 was ascertained its cftemical action, and its powers 

 of decomposing water. 



But the most important discoveries in Voltaism 

 have been made by Sir Humphrey Davy. They^ 

 however, would of themselves fill a volume, and 

 therefore camioi be here detailed. 



LESSON 



