BITUMEN

From Agepedia

BITUMEN ; the name of a species in mineralogy, the individuals composing which have acquired several distinct names, from their diversity in appearance. This depends chiefly upon their state of aggregation, which forms an uninterrupted series from the perfectly fluid to the solid condition.Naphtha, the most fluid variety, is nearly colorless, or of a yellowish tinge, transparent, and emits a peculiar odor. It swims on water, its specific gravity being from 0.71 to 0.84. It burns with a bluishwhite flame and thick smoke, and leaves no residue. It consists of carbon, 82.20, and hydrogen, 14.80; and, being the only fluid destitute of oxygen, it is used to preserve those new metals in, which were discovered by sir II. Davy. It is found in Persia, in the peninsula of Apcheron, upon the western shore of the Caspian sea, where it rises through a marly soil in the form of vapor, and, being made to flow through earthen tubes, is inflamed for the purpose of assisting in the preparation of food. It is collected by sinking pits several yards in depth, into which the naphtha flows. It is burned in lamps, by the Persians, instead of oil. Near the village of Amiano, in the state of Parma, there exists a spring which yields this substance in sufficient quantity to illuminate the city of Genoa, for which purpose it is employed. With certain vegetable oils, naphtha is said to form a good varnish.The variety petroleum is much thicker than naphtha, resembling, in consistence, common tar. It has a strong, disagreeable odor, and a blackish or reddishbrown color. During combustion, it emits a thick, black smoke, and leaves a little residue in the form of a black coal. It is more abundant than the first mentioned variety, from which it does not appear to differ, except in being more inspissated. It occurs, oozing out of rocks, in the vicinity of beds of coal, or floating upon the surface of springs. In the Birman empire, near Rainanghong, is a hill containing coal, into which 520 pits have been sunk for the collection of petroleum ; and the annual product of this mine is 400,000 hogsheads. It is used, by the inhabitants of that country, as a lampoil, and, when mingled with earth or ashes, as fuel. In the U. States, it is found abundantly in Kentucky, Ohio and New York, where it is known under the name of Seneca or Genesee oil. It is used as a substitute for tar, and as an external application for the remedy of rheumatism and chilblains.Maltha is a bitumen, still less fluid than petroleum, from which it differs in no other respect. Its principal locality is at Puy de la Pege, in France, where it renders the soil so viscous, that it adheres strongly to the foot of the traveller. It is also found in Persia and in the Hartz. It is employed, like tar and pitch, on cables and in calking vessels: it is used, as well as the petroleum, to protect iron from rusting, and sometimes forms an ingredient in black sealingwax. Elastic bitumen yields easily to pressure, is flexible and elastic. It emits a strong, bituminous odor, and is about the weight of water. On exposure to the air, it becomes hard, and loses its elasticity. It takes up the traces of crayons in the same manner as the caoutchouc, or Indian rubber, whence it has obtained the name of the mineral caoutchouc. It has hitherto been found only in the lead mines of Derbyshire.Compact bitumen, or asphaltum, is of a shining black color, solid and brittle, with a conchoidal fracture. Its specific gravity is from 1 to 1.6. Like the former varieties, it burns freely, and leaves but little residue. It is found in Judea, in the Palatinate, in France, in Switzerland, and in large deposits in sandstone in Albania; but no where so largely as in the island of Trinidad, where it forms a lake three miles in circumference, and of a thickness unknown A. gentle heat renders it ductile, and, when mixed with grease or common pitch, it is used for paying the bottoms of ships, and is supposed to protect them from the teredo of the West Indian seas. The ancients employed bitumen in the construction of their buildings. The bricks of which the walls of Babylon were built were, according to historians, cemented with hot bitumen, which imparted to them great solidity.