| Description | Smee states that the reduction of a metal from its saline solution by the agency of voltaic electricity has been explained in three different ways. By Hisinger, by Berzelius, and by Faraday it has been ascribed to the liberation of hydrogen in this process; Davy and others considered it as resulting directly from the attraction o the metal to the negative pole; and Daniell conceives that the metal is directly electrolysed by the action of the voltaic circuit. Smee observes that the ends of copper wires, placed in a solution of sulphate of copper between two platina poles in the circuit, manifest electric polarity; so that while one end is dissolving, the other is receiving deposits of copper. He also observes that platina was, in like manner, susceptible of polarity, although in a much less degree than copper, when placed in similar circumstances. With a view to determine the influence of nascent hydrogen in the voltaic reduction of metals, he impregnates pieces of coke and of porous charcoal with hydrogen, by placing them, while in contact with a metal, in an acid solution, when they thus constitute the negative pole of the circuit. He finds that the pieces thus charged readily reduce the metals of solutions into which they are immersed; and thence infers that the hydrogen is the agent in these reductions. From another set of experiments he concludes, that during these decompositions, water is really formed at the negative pole; a circumstance which he conceives is the chief source of the difficulties experienced in electro-metallurgic operations when they are conducted on a large scale, but which may be avoided by a particular mode of arranging the elements of the circuit so as to ensure the uniform diffusion of the salt. Smee obtains the immediate reduction of gold, platina, palladium, copper, silver and tin from their solutions by the agency of hydrogen contained in a tube, with a piece of platinized platina in contact with the metallic salt: nitric acid and persalts of iron, on the other hand, yield their oxygen by the influence of the same agent.
Includes one diagram showing Smee's experimental setup. Annotations in pencil throughout.
Subject: Chemistry / Electricity
Received 28 February 1843.
Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 4 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'On the cause of the reduction of metals from solutions of their salts by the voltaic circuit'.
A version of this paper was published by Smee in The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Smee, Alfred. 'On the cause of the reduction of metals when solutions of their salts are subjected to the galvanic current.' The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, volume 25, number 168 (1844), pp. 434-442. |