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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    observations, and which you will find abundantly suffi- cient for the hour we have to spare. All the ordinary substances from which we obtain light by artificial means may be represented by oil and gas. Here is common olive oil, used in the countries where it is produced for the purpose of obtaining light; and there is a portion of olefiant gas. Although wax, tallow, or anything of that sort be used for the purpose of producing light, yet they all fall under one or other of these deno- minations, inasmuch as they are like the vapour of oil. These are the two substances to which we generally refer the light. I have put down on a table the composition of these two bodies, for your observation this evening, and you will find that the oil contains carbon, hydrogen, and oxygen, and the gas only carbon and hydrogen. The composition of oil is given according to Dr. Ure, of 100 parts, and is divided into— Carbon . . . • • 78 0 Hydrogen . . • ..115 Oxygen . • • • . 10 5 100 0 The gas I refer to is such coal gas as we have in this room, as it is burning here around me, and as commonly used in London ; its composition (according to Henry, I think) is seventy of carbon and thirty of hydrogen per cent. These are the two things which are repre- sented here; in this vessel below there is hydrogen, the other is carbon, which are in their elementary states existing separately; I give you at present the constituents of these two bodies. The oxygen which is there present I need not disturb you with now, inasmuch as it uierges into these other bodies when burning in the air. lne hydrogen, which is a very gaseous body, is burning; there is the carbon, and I will in a moment give you the combination of that body, as I shall want the phenomenon bv and by for the purpose of illustrating a very curious point in these gaseous bodies. This is a piece ot charcoal which I can burn by oxygen of the air, or in pure oxygen gas which I have taken for the purpose; the other is oxygen exactly of the same nature, but in the present case is in the atmosphere. The two instances lllus la e all the modes in which we burn every one of the cornbus-