Online Encyclopedia

Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.

COMBUSTION (from the Lat. comburere, ...

Online Encyclopedia
Originally appearing in Volume V06, Page 759 of the 1911 Encyclopedia Britannica.
» Make a correction to this article.
» Add information or comments to this article.
Spread the word: del.icio.us del.icio.us it!

See also:

COMBUSTION (from the See also:Lat. comburere, to See also:burn up) , in See also:chemistry, the See also:process of burning or, more scientifically, the oxidation of a substance, generally with the See also:production of See also:flame and the See also:evolution of See also:heat. The See also:term is more customarily given to productions of flame such as we have in the burning of See also:oils, See also:gas, See also:fuel, &c., but it is conveniently extended to See also:ether cases of oxidation, such as are met with when metals are heated for a See also:long See also:time in See also:air or See also:oxygen. The term " spontaneous combustion " is used when a substance smoulders or inflames apparently without the intervention of any See also:external heat or See also:light; in such cases, as, for example, in heaps of See also:cotton-See also:waste soaked in oil, the oxidation has proceeded slowly, but steadily, for some time, until the heat evolved has raised the See also:mass to the temperature of ignition. The explanation of the phenomena of combustion was at-tempted at very See also:early times, and the early theories were generally See also:bound up in the explanation of the nature of See also:fire or flame. The See also:idea that some extraneous substance is essential to the process is of See also:ancient date; See also:Clement of See also:Alexandria (c. 3rd See also:century A.D.) held that some " air " was necessary, and the same view was accepted during the See also:middle ages, when it had been also found that the products of combustion weighed more than the See also:original combustible, a fact which pointed to the conclusion that some substance had combined with the combustible during the process. This theory was supported by the See also:French physician See also:Jean See also:Ray, who showed also that in the cases of See also:tin and See also:lead there was a limit to the increase in See also:weight. See also:Robert See also:Boyle, who made many researches on the origin and nature of fire, regarded the increase as due to the fixation of the particles of fire. Ideas identical with the See also:modern ones were expressed by See also:John See also:Mayow in his Tractatus quinque medico-physici (1674), but his See also:death in 1679 undoubtedly accounts for the neglect of his suggestions by his contemporaries. Mayow perceived the similarity of the processes of respiration and combustion, and showed that one constituent of the See also:atmosphere, which he termed spiritus nitro-aereus, was essential to combustion and See also:life, and that the second constituent, which he termed spiritus nitri acidi, inhibited combustion and life. At the beginning of the 18th century a new theory of combustion was promulgated by Georg See also:Ernst See also:Stahl. This theory regarded combustibility as due to a principle named phlogiston (from the Gr.

4Ao'yuar6s, burnt), which was See also:

present in all combustible bodies in an amount proportional to their degree of combustibility; for instance, See also:coal was regarded as practically 1 ay 1 or say pure phlogiston. On this theory, all substances which could be burnt were composed of phlogiston and some other substance, and the operation of burning was simply See also:equivalent to the liberation of the phlogiston. The Stahlian theory, originally a theory of combustion, came to be a See also:general theory of chemical reactions, since it provided See also:simple explanations of the See also:ordinary chemical processes(when regarded qualitatively) and permitted generalizations which largely stimulated its See also:acceptance. Its inherent defect— that the products of combustion were invariably heavier than the original substance instead of less as the theory demanded—was ignored, and until See also:late in the 18th century it dominated chemical thought. Its overthrow was effected by See also:Lavoisier, who showed that combustion was simply an oxidation, the oxygen of the atmosphere (which was isolated at about this time by K. W. See also:Scheele and J. See also:Priestley) combining with the substance burnt.

End of Article: COMBUSTION (from the Lat. comburere, to burn up)

Additional information and Comments

There are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.
Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.

Links to articles and home page are always encouraged.

[back]
COMBINATORIAL ANALYSIS 		[next]
COMEDY

Site © 2006 - Net Industries