Transactions of the North-East Coast Institution of Engineers and Shipbuilders Volume 4 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1888 Excerpt: ... of the coal from a solid to a semi-solid or viscous substance, and in distilling off the coal gas contained therein. If this gas on being released is brought into contact with sufficient air before its temperature has fallen below its point of ignition, its atoms of carbon and hydrogen combine with the oxygen of the air, and an increase of temperature is the result. But if air to supply a' sufficiency of oxygen is not admitted, or the gas is allowed to travel till its temperature has fallen too low before meeting the air, a loss of heat is the result, as we then lose the whole heat which has been rendered latent in the work of distilling the gas, as well as that which the coal gas would supply if ignited. Also, if the air supplied from below the grates, in passing up through the coal should become so charged with carbon as to issue at the top surface in the form of carbonic oxide, an additional supply of oxygen must be given it by air admitted direct above the coal to raise it again to carbonic acid. If this be not done the carbon escapes in this half-burned state, and may not be readily observed, as, carbonic oxide being invisible, there is nothing to detect it by, unless it should meet sufficient oxygen in the uptake, or have still sufficient temperature left on reaching the chimney top, when, if this be the case, on there meeting the oxygen of the atmosphere it will combine with it and become visible as flame; and as carbonic oxide combines with oxygen at a comparatively low temperature, the effects of this are sometimes seen in practice by the interior of uptakes bursting into flames, or by fiery chimney tops. This carbonic oxide flame is of a blue colour, by which it can easily be distinguished from the ordinary red flame which may come into existence...