Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 2, 1802).djvu/47

29&#93; COL similar to tint by which charcoal is made, By this operation, coals arc divested of their humidity, th< -:r arid liquor, and part <»t' their fluid oil. The? arc principally used, where it is necessary to excite in- tense heat, as for the smeltin iron ore, and for processes in which the acid and oiiy particles would be detrimental, as in the drying of malt. Coke-oven is a kind of furnace, of a circular structure, erected for the purpose of converting coal into coke. Such ovens may, however, at the same time he applied toother purposes. On this account, a pa- tent was granted to the Right Hon. Henry Seymour Conway, in June iJSy, for his method of adapting, or conveying the heat arising from the tire of coal, em- ployed in c is, for working r .v engines, baking bread, &c. calcining and fusing ores and me- tals, also for wanning rooms, Sec. heating water and for many other useful purposes, by which means the expence of the coal or other fuel is entirely, or in the greatest part, saved. The leading principle of this pa- tent appears to be the constructing of flues both beneath and on the sides of the oven ; in which regis- ters are inserted. By means of these, the heat is conveyed to the steam-engines, baking-ovens, &c. which are built upon and against the sides of the coke-ovens, and may be increased or diminished at pleasure, by opening or shutting the registers ; the same fire serving both to burn the coke, and to com- municate the requisite degree of heat. • COLD, in natural philosophy, is the privation, or absence of heat. Its immediate efic&s on the human COL [29 are, contraction ofthecuta- is pores, and a temporary ob- tion of insensible perspiration. 11 nee w p ••• : h ■ bai is vul- garly called die " goose skin," and the parts thus affected will not re- cover their usual elasticity, till the spasm be removed, either by external or internal heat, or by fric- tion, which excites the latter. At present, we shall only treat of the consequences resulting from an ex- fcold; having, already consi- I part of this subject under the article Catarrh. Beneficent Nature has enabled our frail and complicated frame, to support the heat and cold of diffe- rent climates,. . il facility $ and though mar. has devised artifi- cial means of defending his body against the action of cold, or more properly, of retaining the inbred, or vital heat, yet it often happens that, by exposure to extreme cold, the fingers, ears, toes, &c. are fro- zen : thus, the natural heat of those parts is reduced to the lowest point consistent with life. If, in such cas.s, artificial heat be too sudden- ly applied, a mortification will en- sue, and thefrost-bitten parts spon- taneously separate. Hence they ought to be thawed, either by rub- bing them with snow, or immersing them in cold water, and afterwards applying warmth in the most care- ful and gradual manner ; by which they will soon be restored to their usual tone and activity. Indeed (a popular writer justly observes), the great secret, or art, of restoring sus- pended animation, consists in nice- ly adjusting die natural and artifi- cial stimuli to the exadt tone of the irritable fibre. As moderate cold produces at first debilitating, and eventually bracing effects on the animal body, 'it