BITUMEN, a mineral substance, remarkable for its inflammability and its strong pecu liar odor; generally, however, supposed to be of vegetable origin. The name, which was in use among the ancient 'Ionians, is variously employed, sometimes to include a number of the substances called mineral resins (see ItEstxs), particularly the liquid min eral called naphtha (q.v.) and petroleum (q.v.) or mineral oil, and the solid ones called mineral pitch, asphalt (q.v.), mineral caoutchoue, etc.; sometimes in a more restricted sense it is applied by minernlogists only to some of these, and by some mineralogists to the solid, by others to the liqnid ones. All these substances are, however, closely allied to each other. Naphtha and petroleum consist ,essentially of carbon and hydrogen alone, 8110 83 per cent. being carbon; the others contain also a little oxygen, which is particularly the case in asphalt, the degree of their appearing to depend upon the prone:Coil of oxygen which they contain, which amounts in some specimens of asphalt to 10 per cent. Asphalt also contains' a little nitrogen. Bituminous substances are generally found in connection with carboniferous rocks, in districts where there is, or evidently has been, volcanic agency. See the articles already referred to. Indeed. most kinds of coal contain B., and a substance essentially the same is produced from all
kinds of to it by distillation; and whether before existing actually formed in the coal, or produced at the time by the action of heat, 13, may often be seen bubbling from pieces of coal after they have begin( to burn on an ordinary tire. Some of the shales of the coal-measures are very bituminous, as is also a kind of marl-slate abundant in some parts of the continent of Europe. See SHALE and MARL.—One of the most interesting of the bituminous minerals is that called mineral mottle/touc or elastic B., and for which the new name of elaterite has been devised, as if to support the dignity of its exalta tion to the rank of a distinct mineral species. It is a very rare mineral, only three locali ties being known for it in the world—the Odin lead-mitie in Derbyshire; a coalmine at 31ontrelais, near Angers, in France; and a coal mine near South Bury, in Massachusetts_ It is elastic and flexible like caoutehouc; and may he used, like it. for effacing pencil. marks. It is easily cut with a knife. Its color is blackish, reddish, or yellowish brown; and its specific gravity is sometimes a little less and sometimes a little more than that of water. It has a strong bituminous odor, and burns with a sooty flame.