76 Galvanism > from Galvani to Ohm. 



d. 1800), who* showed that solutions of metallic salts are also 

 decomposed by the current; and William Hyde Wollaston 

 (ft. 1766, d. 1828) seized on it as a testf of the identity of the 

 electric currents of Volta with those obtained by the discharge 

 of f rictional electricity. He found that water could be decom- 



vy posed by currents of either type, and inferred that all differences 

 between them could be explained by supposing that voltaic 

 electricity as commonly obtained is " less intense, but produced 

 in much, larger quantity." Later in the same year (1801), 

 Martin van Mar um (ft. 1750, d. 1837) and Christian Heinrich 

 Pfaff (ft. 1773, d. 1852) arrived at the same conclusion by 

 carrying out on a large scale} Volta's plan of using the pile to 



V charge batteries of Leyden jars. 



The discovery of Nicholson and Carlisle made a great 

 impression on the mind of Humphry Davy (ft. 1778, d. 1829), a 

 young Cornishman who about this time was appointed Professor 

 of Chemistry at the E-oyal Institution in London. Davy at once 

 began to experiment vvitli Voltaic piles, and in November, 1800, 

 showed that they give no current when the water between the 



y pairs of plates is pure, and that their power of action is " in 

 great measure proportional to the power of the conducting 

 fluid substance between the double plates to oxydate the 

 zinc." This result, as he immediately perceived, did not 

 harmonize well with Volta's views on the source of electricity 

 in the pile, but was, on the other hand, in agreement with 

 , Eabroni's idea that galvanic effects are always accompanied by 

 chemical action. After a series of experiments he definitely 



1 concluded that " the galvanic pile of Volta acts only when the 

 conducting substance between the plates is capable of oxydating 

 the zinc ; and that, in proportion as a greater quantity of 

 oxygen enters into combination with the zinc in a given time, 

 so in proportion is the power of the pile to decompose water 

 and to give the shock greater. It seems therefore reasonable 



* Nicholson's Journal (4to), iv (1800), pp. 187,245: Phil. Mag., vii (1800), 

 p. 337. 



t Phil. Mag., 1801, p. 427. J Phil. Mag., xii (1802), p. 161. 



Nicholson's Journal (4to), iv (1800) ; Davy's Works, ii, p. 155. 



