On the results of a series of experiments on the decomposition of water by the galvanic battery : with a view to obtain a constant and brilliant lime light / by N.J. Callan.

  • Callan, N. J. (Nicholas Joseph), 1799-1864.
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: On the results of a series of experiments on the decomposition of water by the galvanic battery : with a view to obtain a constant and brilliant lime light / by N.J. Callan. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    of platina or cast iron, into a porous cell containing nitrosul- phuric acid. Each of the three acted far more powerfully than the lead plate. The plate coated with the alloy containing the largest proportion of lead acted better than the one whose coat- ing contained least lead, but not so wrell as the plate on which sulphur was burnt. This last plate produced a galvanic current very nearly equal to that of a platina or cast-iron plate. I after- wards put into concentrated nitric acid a piece of the tin which was coated with the alloy of lead and tin, and with sulphur, a piece of one of the alloys of lead and tin and a piece of lead, and left them in the acid for about twenty hours. On taking them out of the acid, I found that a good deal of the lead had been dissolved, but the piece of coated tin and the alloy were merely blackened on the surface. From the results of these experi- ments, it is evident that tin plates, coated with an alloy of lead and tin, in which the proportion of tin is small, are more passive in nitric acid, less oxidable, and consequently better suited for the electrodes of a voltameter than lead plates. The tin plates are stronger and more elastic than leaden ones, and therefore are not so easily brought into contact with each other. It was in last March or April that I discovered that tin plates, coated with an alloy of lead and tin, are less oxidable than lead. Since that time I have in all my experiments used the coated tin plates as electrodes. I have arranged these electrodes in two ways; in one way for a battery of low intensity, and in another for bat- teries of high intensity, or of a large number of cells all in one series. In one of the former arrangements there were twenty plates, each 12 inches by 4; they were all parallel, and separated from each other by slips of wood about y^th of an inch thick. Ten of them were connected with one end of the battery ; these were of course the alternate plates; the other ten were connected with the opposite end. The acting surface of each electrode, including both sides of each plate, was something more than 3 square feet. The electrodes for batteries of high intensity are also parallel and separated from each other, about one-six- teenth of an inch, by a non-conductor. Rut the two outside or terminal plates only are connected with the battery; one with the negative, the other with the positive end. The terminal plate, which is connected with the top iron plate of the volta- meter, must be covered on the outside by a non-conductor, other- wise the voltaic current would pass to the side of the iron vessel, and would not pass through the plates and fluid interposed be- tween the two outside or terminal plates. The cells between each pair of plates must be made nearly water-tight, and must be open only on the top, in order that when the terminal plates are con- nected with the battery, the voltaic current may have no way of