4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



by touching the nerve with a metal rod and the muscle with a different 

 metal rod and allowing the rods to touch, and propounded the theory 

 of animal electricity in a paper he published in 1791. 



Allesandro Volta, a professor of physics in the University of Pavia, 

 Italy, read about Galvani's work and repeated his experiments. He 

 found that the extent of the movement of the frog legs depended 

 on the metals used for the rods, and thus believed that the electric 

 charge was produced by the contact of dissimilar metals with the 

 moisture in the muscles. To prove his point he made a pile of silver 



Voltaic Pile, 1799. 



Volta discovered that electricity could be generated by chemical 

 means and made a pile of silver and zinc discs with cloths, wet with 

 salt water, between them. This was the forerunner of the present- 

 day dry battery. Photograph courtesy Prof. Chas. F. Chandler 

 Museum, Columbia University, New York. 



and zinc discs with cloths, wet with salt water, between them. This 

 was in 1799, and he described his pile in March, 1800, in a letter to 

 the Royal Society in London. 



This was an epoch-making discovery as it was the forerunner of the 

 present-day primary battery. Volta soon found that the generation 

 of electricity became weaker as the cloths became dry, so to overcome 

 this he made his " crown of cups." This consisted of a series of 

 cups containing salt water in which strips of silver and zinc were 

 dipped. Each strip of silver in one cup was connected to the zinc 

 strip in the next cup, the end strips of silver and zinc being terminals 

 of the battery. This was the first time that a continuous supply of 



