Biographical Memoir of Sir Hiimphrij Davy. 1 3 



which is continually renewed. Scarcely had physicians become 

 acquainted with this new and admirable instrument, than they 

 wished to try its effects on every kind of substance. 



About the year 1800, Messrs Carlisle and Nicholson, intro- 

 ducing into the water metallic wires corresponding to the two 

 poles of the pile, saw with surprise that oxygen was evolved 

 near the positive thread, and hydrogen near the negative one. 



The same year, perhaps before them, Ritter, in Germany, 

 had arrived at a more precise result, by placing water in two 

 separate vessels, but communicating with each other by means of 

 sulphuric acid: oxygen and hydrogen were produced indefinitely, 

 each at its pole. He thence concluded, not that the pile decom- 

 posed water, but that the two gases are only water combined 

 with the two kinds of electricity. When an animal fibre, or 

 even the fingers, formed the communication between the two 

 vessels, muriatic acid also appeared at the positive wire ; and 

 some had even concluded, fi-om this circumstance, that this acid 

 was formed of hydrogen less oxygenated than water. Alkalies 

 likewise appeared, of different kinds, according to the circum- 

 stances in which the operation was performed. 



In 1803, two Swedish chemists, Messrs Hisinger and Berze- 

 lius, by repeated experiments, had ascertained the fact, that the 

 decomposing action of the pile extends to bodies of every kind ; 

 that it invariably causes acids and oxygenated substances to ap- 

 pear towards the positive pole, and alkalies towards the negative 

 one ; thus opening a way to the explanation of these different 

 anomalies. 



Mr Davy had observed with attention the progress of these 

 experiments, and, even in 1800, and under the eye of Beddoes, 

 he had operated on water, placed in two separate vases, but em- 

 ploying a strip of bladder as the means of communication. In 

 this experiment, muriatic acid likewise appeared*. In 1801 

 he had made known to the public a kind of pile, differing 

 in some respects from that of Volta, in which a single plate 

 of metal alternated with two liquidsf. In 1802, he had ope- 



• Notice of some observations on the causes of the galvanic phenomena, 

 and on certain modes of increasing the powers of the galvanic pile of Volta. — 

 Nicholson's Journal^ 4to, voL iv. p. 337, 380, and 394. 



*t* An account of some galvanic combinations formed by the arrangement 



