34 Sir H. Davy on the Relations 



expressions, in whicli different words are used and applied to 

 the same ideas, and in which all the phaenomena of nature are 

 supposed to depend on the Dynamic system, or the equili- 

 brium and opposition of antagonist powers. 



The true origin of all that has been done in electro-che- 

 mical science was the accidental discovery of MM. Nicholson 

 and Carlisle, of the decomposition of water by the pile of 

 Volta, April 30, 1800*. These gentlemen immediately added 

 to this capital fact, the knowledge of the decomposition of 

 certain metallic solutions, and the circumstance of the se- 

 paration of alkali on the negative plates of the appai'atus. 

 Mr. Cruickshank, in pursuing their experiments, added to 

 them many important new results, such as the decompositions 

 of muriates of magnesia, soda and ammonia, by the pile ; and 

 that alkaline matter always appeared at the negative, and acid 

 at the positive pole f : and Dr. Henry about the same time 

 made some unsuccessful attempts to decompose potassa in so- 

 lution by the pile, and confirmed the general conclusions of 

 MM. Nicholson, Carlisle, and Cruickshank. In the month of 

 September in this year, I pubHshed my first paper on the sub- 

 ject of Galvanic Electricity, in Nicholson's Journal, which 

 was followed by six others:}:: the last of which appeared in 

 January 1801. In these papers I showed that oxygen and 

 hydrogen were evolved from separate portions of M'ater, 

 though vegetable and even animal substances intervened ; and 

 conceiving that all decompositions might be polar §, I elec- 

 trised different compounds at the different extremities, and 

 found that sulphur and metallic substances appeared at the 

 negative pole, and oxygen and azote at the positive pole, 

 though the bodies furnishing them were separate from each 

 other. In the same series of papers I established the intimate 

 connexion between the electrical effects and the chemical 

 changes going on in the pile, and drew the conclusion of the 

 dependence of one upon the other. In 1802 I proved that 

 galvanic combinations might be formed from single metals, or 

 charcoal and different fluids chiefly acid and alkaline, and that 

 the side or pole of the conducting substance in contact with 

 the alkali was positive, and that in contact with the acid, ne- 

 gative; and in the same year I published, that when two 

 separate portions of water, connected by moist bladder or 

 muscular fibre, were electrised, nitro-muriatic acid appeared at 

 the positive, and fixed alkali at the negative pole§. In the 

 same year Dr. Wollaston placed the identity of the cause of 



• * Nicholson's Journal, vol. xlii. p. ]83. f Ibid. vol. iv. p. 190. 



t Ibid, pp.27.5,326, 337, 394, 380. 

 § Journal of the Royal Institution, 1802. First Series. 



galvanism 



