V. Observations on the electro-chemical influence of long-continued electric currents of low tension

Abstract

1. Scarcely any branch of scientific investigation has yielded more important and interesting results than electro-chemistry, which, as is well known, in the hands of a Davy, demonstrated the existence of the alkaline metals, and formed a memorable and important epoch in the history of chemical science. Sir Humphry Davy availed himself of the energetic influence of voltaic currents in a high state of tension, and elicited by means of large batteries. To M. Becquerel, however, we are almost en­tirely indebted for our knowledge of the chemical agency of feeble currents in reducing certain refractory oxides to the metallic state, although it must not be forgotten that Dr. Edmund Davy applied the power of weak currents of electricity to the detection of the metallic poisons, by reducing them to the reguline state. Bucholz appears, in 1807, to have succeeded in obtaining crystals of metallic copper by the aid of a simple voltaic circle. But it is to our illustrious countryman Dr. Faraday that we owe our acquaintance with the interesting circumstance of the power possessed by a current of very low intensity (elicited by a single pair of platinum and zinc plates) in decom­posing several saline combinations, as the iodide of potassium, sulphate of soda, &c., and isolating their respective constituents. In offering the following observations, I have not sufficient presumption to suppose them to be possessed of any very important or original value; but being, as they are, the results of carefully repeated experiments, and containing an account of what I believe to be some previously unobserved facts, I deem myself justified in submitting them to the notice of the Royal Society.