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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    up for eighteen hours; for the light would last only five seconds in each minute, and consequently only five minutes in each hour, or an hour and a half in eighteen hours. Therefore, since the three gas bags, filled with the mixed gases, would maintain a constant light for an hour and a half, they should keep up the intermittent light for eighteen hours. I believe such an inter- mittent would answer very well for lighthouses. In the light- house on the eastern pier at Kingstown, the light is a revolving one, which completes a revolution in about a minute. The bril- liant white light, the only one which can be seen at a distance, shines out only for about five seconds in each minute. Hence I infer that an intermittent lime light which lasts for five seconds in each minute would be sufficient for lighthouse purposes. It is necessary to observe, that, when gases are gradually cut off from the jet, the gases in the upper part of the voltameter, or vessel to which the jet is attached, will explode if a Ilemming's jet be not used; and this explosion, though perfectly free from danger, will be attended with inconvenience, for a vacuum will be produced in the upper part of the voltameter or vessel, and no gases can pass to the jet till this vacuum is filled. Hence, in producing an intermittent lime light, a Ilemming’s jet should be employed. Since the discovery of the cast-iron battery, several persons have obtained patents for apparatuses for the coke light, or, as it is now called, the electric light. If they arranged their apparatus so as to produce an intermittent coke-light similar to the intermittent lime light I have described, they would confer a great benefit on society. When the coke light is constant, the battery is soon exhausted, the coke points are consumed, and must be frequently renewed; but were the light intermittent, a single charge of the battery might last for an entire night, and it would be sufficient to renew the coke points two or three times in the course of the night. And if an intermittent coke light were used in lighthouses only on very dark and foggy, nights and in snow-storms, the expense could not be considerable. I think the coke light is more intense than the lime light, and also somewhat less expensive. To produce a coke light sufficient for all illuminating purposes, forty cast- iron cells, each containing a zinc plate 2 inches by 4, will suffice. To obtain a lime light of equal illuminating power, a battery containing at least twice as large a surface of zinc will be required. A battery with a given charge will scarcely work twice as long in decomposing water as in igniting a pair of coke points. There- fore, on the whole, I think the lime light is more expensive, but much more easily managed than the coke light. The former requires a battery of only four large plates; the latter depends on the intensity of the current, and requires a battery of at least thirty-five or forty cells. The coke points will require to be