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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    and the copper point with the positive end, the light will be worthless. I forgot to make this experiment when I had occa- sion to use a very powerful battery. I may mention here that with 00 cast-iron cells in which the zinc plates were 2 inches by 4, I was able to fuse and deflagrate a round piece of steel ^ inch diameter. Although I made a far greater number of experiments on the lime light than on the coke light, I am not able to state positively the size of the battery, which, by decom- posing water, would produce a lime light equal in illuminating power to that of a pair of coke points ignited by a battery of 40 cast-iron cells in which the zinc plates are 2 inches by 4. I can only say that I think it probable that a battery twice, or very nearly twice the size, would be required. With regard to the length of time the two batteries would work with a given charge, I am equally uncertain. In decomposing water, all the cells must be arranged in rows of four each, so that the intensity of the current may not exceed that of 4 cells. Now, when a current is sent from 4 cells through a good conducting fluid, the quantity of electricity which passes through the fluid and through each cell of the battery is only about one-half of the quantity which would pass if the ends of the battery were con- nected by a shoi’t, thick wire. This I have found by the galva- nometer. Hence the battery would work about twice as long in the former as in the latter case. When the coke points were ignited by 40 cells, I measured the angle of deviation of the sine galvanometer, and found it to be 31° when the needle was in the axis of the coil, and nearly 10 inches from its centre. When they were ignited by 60 cells, the deviation was 40°. Unfortunately, I did not measure the angle of deviation which would be produced by the current passing directly through the coil of the galvanometer. The experiments were made before my class, and I intended to measure on the next day the angle of deviation which would be produced by the current from 4 cells of the same size, sent through a fluid. I was prevented from making the experiment until I had occasion to remagnetize the needle, and consequently I cannot now depend on its indications being the same they would have been on the day the battery of 40 and 60 cells was used. I have since tried the effect of a current from four of the cells on the sine galvanometer after passing it through a solution of carbonate of soda, and found -that a deflection of 22|° was produced in the needle of the sine galvanometer. But I am inclined to think that had I made the experiment the day I used the 40 cells, the deflection would have been considerably less, because the needle was not then so highly magnetized. The impression made by all my experiments inclines me to believe that a battery would work nearly twice as long in decomposing water as in igniting coke points; that, therefore, the coke light and the lime light are nearly equally