Lecture on light and ventilation : delivered at the Royal Institution, April 7, 1843 / by Professor Faraday.

  • Faraday, Michael, 1791-1867.
Date:
[1843]
Catalogue details

Licence: Public Domain Mark

Credit: Lecture on light and ventilation : delivered at the Royal Institution, April 7, 1843 / by Professor Faraday. 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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    the oil or gas which is burnt. That lower table which I have affixed there to the wall represents to you, in a strong manner, the effects which are thus produced. (Referring to a table of products.) A pound of oil pro- duces, because of the hydrogen it contains, rather more than a pound of water. A pound of olive oil, if burnt in the atmosphere, or oxygen, or in any other way, will produce rather more than a pound of water. Why ? For this reason—that it takes from the atmosphere that portion of oxygen which the hydrogen produces—the water which you saw just now, when I held that glass jar over the jet of hydrogen. Now that is a jar in which no animal could live. The light takes the oxygen from the atmosphere, and forms with it water, and that water amounts to rather more in weight than the oil itself, because the one part of hydrogen in the oil takes eight parts of oxygen from the atmosphere, and thus produces nine parts of water. The carbon of the oil, which is seventy-eight, will produce two pounds and eighty-six hundredths (which would amount to nine-tenths) of carbonic acid. And it takes in doing this two pounds eight ounces, or nearly three pounds, of oxygen from the atmosphere; and it spoils thirteen pounds and a quarter, or one hundred and seventy-two and a half cubical feet of air, which is deprived of its oxygen, and thereby partially spoiled, and which, if we could carry on the process so far, would be utterly destroyed—the whole of the one hundred and seventy-two and a half cubical feet of air. But look at gas, for that contains a greater proportion of hydrogen. I will give you London gas, for example. A pound of gas produces as much as two pounds and three-quarters of water; it produces two pounds and a half, or rather more, of carbonic acid, and takes twenty- one pounds and a quarter of oxygen from the atmosphere, and spoils nineteen pounds and one-third of air, or con- sumes 251 cubical feet. The carbon which is found in all the gas we burn, is by no means an innocent thing. It is an exceedingly noxious and deleterious substance, and is instantly fatal to animal life. If I could take a portion of common air, and convert the oxygen into carbonic acid, and mix that air with other air, although there is so much nitrogen, it would still be fatal to human life. Now air, I will say, containing so much as only one-tenth of carbonic acid, is