On the combustion of gas for economic purposes / by Henry Letheby.

  • Letheby, H. (Henry), 1816-1876.
Date:
[1866]
Catalogue details

Licence: Public Domain Mark

Credit: On the combustion of gas for economic purposes / by Henry Letheby. 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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    ON THE COMBUSTION OF GAS FOR ECONOMIC PURPOSES. By HENRY LETHEBY, Esq., M.B. [A Lecture delivered before the British Association of Gas Managers, at St. Martin's Hall, London, on Wednesday, May 23, 1866.] From the Journal of Gas Lighting, &c, June 12, 1866. Mr. President and Gentlemen,—At the close of the last lecture which I had the honour of delivering to this association at the meeting in Birming- ham, I referred very briefly to the general phenomena of gaseous combus- tion, and to the principles of the economic use of coal gas. It was my in- intention, indeed, to have entered fully into this matter; but so much time was occupied in the examination of the chemical and physical properties of the most important constituents of coal gas, that little was left for the consideration of this part of our subject. I have therefore been requested to make it the especial subject-matter of this evening's lecture; and in order that you may follow me through the various details of the inquiry, it will be necessary to pursue it from the beginning. The phenomena of visible combustion are always the results of energetic chemical action; and the heat and light which characterize it are the con- sequences of the violent collisions and rapid trembling of the combining atoms. When this collision occurs by the showering down, as it were, of gaseous atoms upon a solid, as you here see in the combustion of carbon and of iron in oxygen gas, and of antimony in chlorine, there may be a very intense ignition of the solid, but there is no flame. On the other hand, when the conflict is entirely among the particles of gaseous or vaporous matter, or matter in a finely divided and mobile condition, the phenomena are altogether different; for although, as before, the atoms or molecules of the burning body are intensely heated, yet from their mobility they give rise to that appearance called flame. In all cases, therefore, we must regard flame as gaseous, or vaporous, or very finely divided matter intensely heated. That the particles of the gas or vapour must be themselves bodily and intensely heated to produce flame is evident from this—that when I burn hydrogen, or coal gas, or the vapour of ether, or alcohol by means or a finely divided solid, as I do here with a rosette of fine platinum wire, you see how the wire glows; but there is no flame, for the combustion is limited to the thin layer of gaseous matter which immediately surrounds the metal, and the temperature of the combustion is comparatively low. But if I raise it to a higher temperature, as will some- times happen of itself, then the whole mass of escaping gas or vapour is thrown into a state of ignition, and it bursts into flame. Let ng pause for awhile to study the complicated nature of this phenome- non. Whenever a gas or vapour burns in an atmosphore of another gas or vapour, as we here sec in the flame of the burning i;ns and candle, the A