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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    attacking the positive electrode. When the plates were connected with the opposite ends of a battery, the water was rapidly de- composed,and a considerable quantity of the mixed gases obtained. From the intensity of the lime light produced by the gases, it appeared that the potash effectually prevented the combination of the oxygen with the positive electrode. The iron plates worked well for about an hour; the decomposition then began to decline very rapidly, though the battery was in good order. I then took up the iron plates, separated them from each other, and removed the linen cover. One of the plates was coated with a non-conducting black deposit. This was the first time I found such a deposit on either of the plates; on all former occasions they were separated from each other by slips of wood or gutta percha. I afterwards got a pair of lead plates, which I rolled up in the same way as the iron plates; they, too, ceased to act after some time, because one of them became covered with a black non-conducting substance. I then got four concentric hollow cylinders made of sheet iron ^th of an inch thick, so that the largest of them fitted in the iron vessel. The first or inner- most one was connected with the third, and the second with the fourth; they were separated from each other by wedges of wood, and also insulated from the bottom of the vessel. The first and third were connected with the top plate, and the second and fourth with the side of the vessel. These acted tolerably well; but when I used a pair of lead electrodes with a battery of ten 6-inch plates, the lime light was considerably larger and more steady than when I employed the iron cylinders. Hence I resolved, if possible, to give up the use of iron electrodes. I saw at the same time that lead plates would not answer; for when they are placed near each other, a slight pressure, and sometimes even their own weight, brings them into contact with each other. It then occurred to me to try strong tin plates immersed for a few seconds in melted lead, or in a liquid alloy of lead and tin, in which alloy the quantity of tin would be small compared with that of lead. Not having any new tin plates at hand, I cut up some old tin vessels, and made three plates, each nearly 4 inches wide and 6 long. I coated one of them, by means of a soldering iron, with an alloy, containing about seven parts by weight of lead and one of tin • and another with an alloy containing about three parts of lead and one of tin. On the third, after being coated with the alloy, I sprinkled some powdered sulphur, and held the plate over the fire until the sul- phur was inflamed: the plate was thus covered with a black coating of burnt sulphur. I then tried each of the three, and also a plate of lead about the same size, as the negative element of a nitric acid battery; that is, I put each successively, instead