Rock oil,
mineral oil, or
natural oil, a dark
brown or greenish
inflammable liquid, which, at determined points, exists in the
upper strata of the land, from whence it is pumped, or
forced by pressure of the
gas attending it. It consists of a
composite mixture of different hydrocarbons, largely of the
methane series,
but may
vary many in appearance, composition, and properties. It is refined by distillation, and the commodity include kerosene, petrol, gasoline, paraffin, etc. Petroleum spirit, a
volatile liquid obtained in the
distillation of crude
petroleum at a
temperature of 170 deg Fahr, or adown. The
term is rather loosely applied to a considerable
range of commodity, including petrol and ligroin. The terms
petroleum ether, and naphtha, are sometimes applied to the still more
volatile commodity, including rhigolene, gasoline, cymogene, etc.
Origin: NL, fr. L. Petra a
rock + oleum oil: cf. F. Petrole. Cf. Petrify, and Oil.
Source: Websters Vocabulary