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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    that of four cells in series ; because if a battery of 100 cells be arranged in series, a single bad porous cell or bad zinc plate will diminish considerably the power of the entire battery; but if the 100 cells be arranged in twenty-five rows, each con- taining four cells, and all the terminal zinc plates be connected so as to act as one plate, and all the end iron cells be connected so as to act as one, a bad porous cell or zinc plate will diminish the power only of the row to which it belongs, but not of the other rows. Some of my experiments led me to believe, that, by means of the arrangement of the electrodes for a current of high intensity, the decomposing power of the battery may be considerably in- creased ; from other experiments I was somewhat disposed to infer that by such arrangement no increase of power can be gained. I am at present in doubt, and must remain so till the state of my health enables me to repeat my experiments. The fluid which I first used in the voltameter was a solution of caustic potash. When a current was sent through the solu- tion, the iron vessel was soon filled with foam, which came out through the jet with the mixed gas and extinguished the flame. I then tried a solution of carbonate of soda. The soda prevented the oxidation of the positive electrode as well as potash, and did not foam so much. However, even with soda, the quantity of foam was so great, that the iron voltameter, 16 inches high and 6 inches in diameter, would be very soon filled with it if a bat- tery of more than about twelve 6-inch cells were employed. I tried various means of preventing the foam. I first covered the electrodes all round with a cloth, so that the gases should pass through it. Many of the bubbles were thus broken ; but when a powerful battery was used, the voltameter was soon filled with foam. I then put about a teaspoonful of coal naphtha into the vessel. This prevented the foam from rising to any considerable height in the vessel, but it was somewhat injurious to the light. I also tried turpentine: it diminished the foam, but injured the light more than the naphtha. I think it increased the vio- lence of the explosion of the gases. I afterwards tried some nitre, and also common salt; each of them prevented the foam, but destroyed the light. After failing in all my efforts to prevent the foam, I thought there was no alternative but to get an iron vessel so large that all the foam which could be produced by a powerful battery would be contained between the top of the elec- trodes or surface of the fluid, and the top of the vessel without rushing through the jet. Latterly, I have tried carbonate of am- monia instead of soda, and have found that it foams much less, and that it prevents the action of the oxygen on the positive elec- trode. A solution of the proper strength will be obtained by dissolving an ounce and a quarter, or an ounce of the carbonate