'. ^>^tisr.^^'T- 



Figure i . — Galvani's experiments in animal electricity. From Luigi Galvani, 

 De Viribus Electricitatis in Motu Musculari Commenlarius, Bologna, 1791, trans- 

 lated by Margaret Foley, Norwalk, Connecticut, 1953, pi. 3. 



The Electrochemical Cell 



Luigi Galvani, professor of anatomy at Bologna, 

 was studying the relation between electricity and mus- 

 cular tissue when he discovered that if the exposed 

 nerve of a frog's leg were touched by metals under 

 certain conditions, a contraction of the muscle would 

 result (figs. 1, 2). This discovery led Galvani to ex- 

 plain muscular contractions in terms of an electrical 

 nervous fluid being conducted, stored, and dis- 

 charged.' Tissue, living or dead, was the receptacle 

 of this fluid, and so could act as a kind of Leyden jar. 

 Previous experience had shown that a Leyden jar 

 could produce a spark only after "electrical fluid" had 

 been condensed in it; however, an electrical effect 

 could be detected in the tissue each time. Because 

 of this, the suspicion arose that perhaps the electrical 

 fluid might be some kind of life force. 



' Luigi Galvani, De Viribus Electricitatis in Motu Musculari 

 Commenlarius, Bologna, 1791, translated by Margaret Foley, 

 Burndy Library Publication No. 10, Norwalk, Connecticut, 

 1953. 



Galvani's explanation was first elaborated ^ and 

 then contested ^ by Alessandro Volta, who finally 

 concluded that animal tissue was not necessary to 

 produce the electrical effect and that all that was 

 needed was two dissimilar metals separated by a poor 

 conductor.'' As a result of his research, Volta was 

 able to design his famous voltaic pile (figs. 3, 4), which 

 multiplied the effect of a single pair of dissimilar 

 iTietals. The pile was formed by stacking pairs of 

 metals separated by disks of paper moistened with salt 

 water in the sequence: silver-paper-zinc-silver-paper- 

 zinc, etc. These piles were found to increase their 



- Alessandro Volta, "Account of Some Discoveries Made by 

 Mr. Galvani, of Bologna; with Experiments and Observations 

 on Them," Philosophical Transactions of the Royal Society of London 

 (hereinafter referred to as Philosophical Transactions), 1793, 

 vol. 83, pp. 10-44. 



' Allesandro Volta, "Observations on Animal Electricity; 

 Being the Substance of Two Letters from A. Volta to Professor 

 Gren," Philosophical Magazine, 1799, vol. 4, pp. 59-68, 163-171, 

 306-312. 



< Alessandro Volta, "On the Electricity Excited by the Mere 

 Contact of Conducting Substances of Different Kinds," Philo- 

 sophical Magazine, 1800, vol. 7, pp. 289-311. 



234 



BULLETIN 228 : CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



