The Evolution of Forces (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 edition. Excerpt: ...the same temperature. At 1650 C. the Auer mantle, soaked in a solution of oxide of thorium containing 1 per cent. of oxide of cerium, emits a great number of brilliant visible, and relatively few invisible, radiations. If we modify the proportions of the two oxides, we see the relation of the waves emitted at the same temperature equally modified. The visible radiations diminish, and the invisible increase. Since these last produce much more heat than the visible, it has been thought to utilize the incandescent burner for heating purposes by simply modifying the proportion of the oxides with which the mantles are steeped. We thus obtain burners of little illuminating power but giving forth a good deal of heat, while the burners used for lighting give out, on the contrary, much light and little heat. The radiation of bodies generated by heating is produced by all actions capable of increasing their vibrations, especially those chemical reactions which furnished the early modes of lighting. As a type, we may quote the combustion of ordinary gas. Formed by a mixture of hydrogen and of carbides of hydrogen, it combines violently with the oxygen of the air when lighted. The particles of carbon from the carbide, being liberated and brought to incandescence, give the flame a brilliancy which pure hydrogen does not possess. Gas therefore only owes its brilliancy to these incandescent particles held in suspension. Any solid body whatever--platinum, for examplemight replace the particles of carbon. In reality, the phenomena which take place in any kind of flame--that of a simple candle, for example--are quite otherwise complicated. So much is this the case that we might consider a body in combustion, such as a lighted candle, as one of the phenomena..