The Chemical History of a Candle
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By Michael Faraday
This series of six lectures was originally delivered by Michael Faraday to the Royal Institution of Great Britain in 1820-1821. This subject was chosen because, as Faraday explained, "There is not a law under which any part of this universe is governed which does not come into play and is not touched upon [during the time a candle burns]." From the seeming simplicity of a lit candle he explores the components, function, and weight of the atmosphere; the function of a candle wick; capillary attraction; the carbon content in oxygen and living bodies; the production of carbon dioxide from coal gas and sugar; the properties of carbonic acid; respiration and its analogy to the burning of a candle — all in a vivid, conversational manner.
I have here a piece of carbon or charcoal, which will burn and give us light exactly in the same manner as if it were burnt as part of a candle. The heat that is in the flame of a candle decomposes the vapor of the wax, and sets free the carbon particles; they rise up heated and glowing as this now glows, and then enter into the air. But the particles, when burnt, never pass off from a candle in the form of carbon. They go off into the air as a perfectly invisible substance, about which we shall know hereafter.
Dover Publications, 2003 reprint, paperback, 240 pages, B&W illustrations.