HISTORY OF GALVANISM. 



SECTION II. 



Experiments from the Discovery of the Pile to 

 the Decomposition of the Alkalies. 



THE second period of the history of galvan- Discovery 



.,, ,, . j. of the pile 



is m commences with the important discovery Dy Voita, 

 made by Volt a, of the instrument which has been 1{ 

 called the galvanic or voltaic pile. Volta, as has 

 been remarked above, adopted the idea, that the 

 action excited by the two metals depended upon 

 an alteration in their respective states of electricity, 

 or in a destruction of its equilibrium. The effect 

 produced by one pair of plates could only be 

 comparatively small ; but he supposed that by 

 interposing- a conductor between several pairs of 

 plates, it might be multiplied and concentrated in 

 an indefinite degree. He accordingly provided a pescrip- 

 number of silver coins, and pieces of zinc of simi- 

 lar dimensions ; these were disposed in pairs, and PLATE i. 

 between each pair was placed a piece of card ' s ' 

 soaked in water ; and thus a pile or column was 

 formed, in which the three substances silver, zinc, 

 arid, water, existed in regular rotation. The effect 

 of the combination fully justified the expectations 

 of the discoverer. All the phenomena that had Effects, 

 been excited by a single pair of metals were far 

 exceeded by those of the pile, while by touching 

 the two ends of it at the same time, it was found 



