GALVANIC ELECTRICITY. 47 



were removed. These phaenomena continued till 38 minutes after 

 the amputation, when the limb became cold. 



The principle, however, upon which the electric pouer acted was 

 misunderstood; nor were any means as yet devised by which the 

 new power could be accumulated to any definite extent, or made ap. 

 plicable to any useful purposes. 



Galvani explained the phenomenon by conceiving the muscles 

 to resemble a charged Leyden phial, having electricity accumulated 

 in the inside, while the outside was minus. The nerves he conceived 

 to be connected with the inside: when it was united with the out. 

 side by conductors, the surplus electricity was discharged, and hence 

 the motions of the limb. 



M. Volta, professor of natural philosophy at Como in the Mila. 

 nese, soon discovered, however, that the convulsions were produced 

 by a different operation of the electric principle; in reality by merely 

 touching two different parts of the same nerve by two different me. 

 tals, and thus making a circuit of the three substances, of which the 

 part of the nerve selected for the purpose formed the middle : and 

 pursuing this simple but beautiful law, he soon afterwards perceived 

 that the two distinct metals alone had an action upon each other 

 when brought into contact, but that the action was considerably in. 

 creased by the interposition of a third substance of a different na. 

 ture. The hypothesis of Galvani was hereby completely destroyed, 

 and a foundation laid for that wonderful electric column which has 

 been called the galvanic, or more correctly the voltaic pile, which, 

 by the simple means of multiplying plates of two different kinds of 

 metal, with an interposition of a plate of some other substance be- 

 tween each, produces such an accumulation of electric power; and, 

 when the force of the opposite ends is brought into approximation 

 by means of a flexible wire, or other conductor, attached to each 

 end, such an exertion of this power as to become one of the most, 

 if not altogether the most energic agents in chemistry. And we 

 now advance to the second and most important stage of this new 

 branch of natural science; for which the world is entirely indebted 

 to the penetrating genius of M. Volta, and the curious facts and 

 phenomena of which have hence been universally denominated 

 voltaism. 



M. Volta commenced his experiments in 1793, and it was seven 

 years before he rendered his pile sufficiently satisfactory and perfect 

 to usher its description and powers before the public. This, how- 



