Soot, or that substance formed by the combustion of wood, &c. which collects in chimnies, is used in some of the pyrotechnical preparations, partly to assist the flame, and partly to modify its appearance. It is found, that soot, produced by the combustion of wood, is formed by the condensation of the carbon evolved in the smoke. It also contains volatile products, the nature of which, depends on the kind of combustible. Wood-soot is considered a good manure, on account of the carbon and some volatile salts, it is said to contain. That it contains ammonia, is evident, since it may be detected by experiment; and that this alkali is combined with carbonic acid, and sometimes with muriatic acid, a number of facts prove. Soot, then, when used in fire-works, may, like sal ammoniac, but in a lesser degree, produce a particular coloured flame. When soot is well washed in water, in order to free it from saline and other soluble matter, and probably from pyroacetic acid, and then pulverized, it forms the pigment called _bistre_. It is a fact, that the excrement of some animals, the camel for instance, which feed on saline vegetables, when burnt, will yield a soot, which contains an abundance of muriate of ammonia, or sal ammoniac. Hence, by re-subliming this soot, sal ammoniac was originally prepared in Egypt. The quantity of muriate of ammonia, contained in the soot of camels' dung, is considerable. It is found that 26 lbs. of soot yield on an average 6 lbs. of that salt; See _Sal Ammoniac_. Camels' dung, and in fact the dried excrement of animals, furnish a very good fuel. In Egypt it is used with advantage. The soot of oil, &c. is of a different kind; it is the substance, which forms our lampblack. _Sec. X. Of Turpentine, Rosin, and Pitch._ All these substances enter into the composition of fire-works, either to increase the rapidity of combustion, as in incendiary fire-works, or, in some cases, as with rosin, to produce a coloured flame. That they contain carbon and hydrogen, as their principal ingredients, is well known; to which we may attribute their rapid combustion, and the facility with which they decompose nitrous salts. The Greek fire, for example, owed, it is said, its powerful effect to turpentine, which, with other substances employed, made the composition remarkably inflammable, and the decomposition of the nitre, (which some say it contained) so rapid, as even to defy the action of water.