NAPH'THA -is derived, frpm the word varata, to exude, and was originally applied to an inflammableliquidlyflrocarbon (or rather a mixture of several hydrocar bons) which exudes from the soil in certain parts of Persia. (According to Pelletier and Walter, it consists of three hydrocarbons—viz., which boils at 190*; which boils at 239°; and which boils at 874°.) The term is, however, now used not only to designate a similar and almost identical fluid, that issues from the ground in many parts of the world, and is known as petroleum, rock-oil, etc., but is also applied to other liquids which resemble true naphtha in little else than their volatility and inflam mability. Thus, wood-spirit, or methylic alcohol, is often spoken of as wood-ropktIur, and acetone is sometimes described as naphtha. Coal-tar yields by distillation a liquid which has a heavier specific gravity and a lower boiling-point than Persian naphtha, but resembles it in general properties, and can generally be substituted for it. Sec GAS-TA t:.
Crude naphtha, whether occurring as a natural product or as obtained from coal tar, is purified by agitation with strong sulphuric acid; after which it must be well washed with water (in which it is quite insoluble), and finally distilled from quicklime. Pure naphtha is colorless, and of a peculiar taste and odor; it is soluble in about eight times its bulk of alcohol, and dissolves in all proportions in ether and in essential oils. Hot naphtha dissolves phosphorus and sulphur, but deposits them on cooling. It is an excellent solvent for gutta-perelm, caoutchouta camphor, and fatty and resinous bodies generally; and hence it is extensively used in the arts for these purposes, and its employ ment as a source of artificial light is now becoming universal. In consequence of its containing no oxygen, it is employed by chemists for the preservation of potassium and other metals, which have a powerful affinity for oxygen. Owing to its volatility and inflammability, it must be handled with great caution, many fatal cases having arisen from its vapor catching lire on the approach of a candle.
The principal kinds of naphtha known in commerce are native naphtha, coal naphtha, Boghead napluha (also called paraffin oil and photogen), shale naphtha, and naphtha from caoutchoue : n.1 ea-machine.
Native naphtha, petroleum, or rock-oil is found in many parts of the world, as in Japan, Burma. Persia, the shores of the Caspian sea, Siberia, Italy, France, and North America. It is of various degrees of consistency, from a thin, light, colorless fluid found in Persia, with a specific gravity of about 0.750, to a substance as thick as butter, and nearly as heavy as water. But all the kinds when rectified have nearly the same constitution. They contain no oxygen, and consist of carbon and hydrogen compounds only. Bitumen and asphaltum are closely allied substances in a solid or semi-solid form. From a very early period in Persia and Japan, and at least since last century in Italy, native naphtha has been used to burn in lamps.
Coal-tar naphtha (see GAS-TAR), as stated above, is of a higher specific gravity than native naphtha—viz., from 0.860 to 0.900, and has a more disagreeable and penetrating odor.
Paraffin oil, for some time• known also as Boghead naphtha, has become, of late years, so important a manufacture that a brief history of its origin cannot be uninterest ing. In the year 1847 Mr. James Young, now of the Batfigate chemical works, had his attention called to a petroleum spring at Alfreton, in Derbyshire, from which he dis tilled a light thin oil for burning in lamps, obtaining at the same time a thicker oil,which was used for lubricat machinery. After a year or two the supply began to fail, but Mr. Young, noticing that petroleum was dropping from the sandstone roof of a coal mine, conjectured that it originated by the action of heat on the coal-seam, the vapor from which had condensed in the sandstone, and supposed from this that it might be produced artificially. Following up this idea, he tried a great many experiments, and ultimately succeeded, by distilling coal at a low red-heat, in obtaining, a substance resembling petroleum, which, when treated in the same way as the natural petroleum, yielded similar products. The "2,1fiaining of these oils and the solid substance paraffin from coal formed the subject of his now celebrated patent, dated Oct. 17, 1850.