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SCIENTIFIC RESEARCHES,

may be found most suitable to operate with, the one on the copper side and the otheron the zinc side. Twelve plates, six inches square, answer very well for decomposingacidulated water, when a solution of sulphate of copper occupies the copper cells, anda dilute solution of soda the zinc cells. Such a battery will he found to possess manyrecommendations. W. S.

Account of some Magnetic Electrical Experiments made by means of an OriginalDischarging Apparatus attached to the Large Magnet, at the Exhibition Room,Adelaide Gallery, Lowther Arcade, London.

To the Editors of the Philosophical Magazine and Journal.

Gentlemen, —Having obtained permission of the proprietors of the ExhibitionRoom, Adelaide Gallery, to employ their large magnet in any new experiments thatI might wish to undertake, I availed myself of that privilege for the first time onThursday evening, the 28th of August last. The following results were pro-duced :—

The decomposition of hydriodate of potassa in solution—first, by paper moistenedin it, and placed on a platinum plate attached to the negative side of the circuit, andoccasionally closing the circuit on the upper side of the paper with a platinum wirewhich proceeded from the positive side, the machine being at work during the time:at each touch of the wire with the paper, however short the time of contact, iodinewas evolved at the positive point of the platinum wire.

Second, a solution of the hydriodate and starch was placed in a rectangular glassbox, with a gauze partition to divide it into two compartments. A platinum plate,properly connected with the machine, was placed in each compartment. In half aminute the positive cell was completely obscured by liberated iodine. A more strik-ing experiment was never exhibited. Platinum wires, properly arranged in the cir-cuit, were placed in solution of acetate of lead : the metal was revived on the negativewire.

Solution of sulphate of copper was also subjected to the action of the current:decomposition immediately took place, and the negative wire became completelycovered with copper.

Water was also decomposed, the hydrogen and oxygen being collected in separatetubes.

The above experiments were repeated by reversing the direction of the current, andthe results were exhibited as decidedly as before, and with the same promptitude asby the employment of a Voltaic battery.