| coal dust | <chest medicine> Fine particulate coal dust that is a known respiratory irritant. Coal dust is the underlying cause of the occupational lung disease known as black lung. (27 Sep 1997) |
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| coal oil | Rock oil, mineral oil, or natural oil, a dark brown or greenish inflammable liquid, which, at certain points, exists in the upper strata of the earth, from whence it is pumped, or forced by pressure of the gas attending it. It consists of a complex mixture of various hydrocarbons, largely of the methane series, but may vary much in appearance, composition, and properties. It is refined by distillation, and the products include kerosene, benzine, gasoline, paraffin, etc. Petroleum spirit, a volatile liquid obtained in the distillation of crude petroleum at a temperature of 170 deg Fahr, or below. The term is rather loosely applied to a considerable range of products, including benzine and ligroin. The terms petroleum ether, and naphtha, are sometimes applied to the still more volatile products, including rhigolene, gasoline, cymogene, etc. Origin: NL, fr. L. Petra a rock + oleum oil: cf. F. Petrole. Cf. Petrify, and Oil. Source: Websters Dictionary (01 Mar 1998) |
| coal tar | <pharmacology> A byproduct obtained during the breakdown of bituminous coal used in the treatment of some skin diseases (for example psoriasis). (27 Sep 1997) |
| coal tar naphtha | <chemistry> A volatile, very inflammable liquid, contained in the naphtha produced by the destructive distillation of coal, from which it is separated by fractional distillation. The name is sometimes applied also to the impure commercial product or benzole, and also, but rarely, to a similar mixed product of petroleum. The Benzene nucleus or Benzene ring, is a closed chain or ring, consisting of six carbon atoms, each with one hydrogen atom attached, regarded as the type from which the aromatic compounds are derived. Structure: C6H6 Origin: From Benzoin. (06 Aug 1998) |
| day-coal | <chemical> The upper stratum of coal, as nearest the light or surface. Source: Websters Dictionary (01 Mar 1998) |