KEROSENE (Gr. keros, wax), the name of a mixture of certain fluid hydrocarbons used for illumination. It has been prepared from bituminous coal and shales, asphalt urns and wood, and from rosin, fish-oil, and candle tar; but is now more economically obtained from petroleum. The density of the mixture called kerosene should be about ..810 or 43° Baum& and should not yield inflammable vapors below a temperature of 110' or 120° F. It is, therefore, not explosive under ordinary circumstances, and a lighted match maybe plunged into it without igniting it. If. however, it be burned in a metal lamp, and this be heated to 115° or 120° F., gases might be formed in the upper part of the lamp which, on taking off the cap or burner, might cause an explosion. But there are many lighter hydrocarbons in petroleum, and much of the kerosene in market con tains them in greater or less proportion. They are cheaper than the heavier oils con tained in the kerosene, and there is a temptation among dealers to mix them with this article after it is bought of the manufacturer or wholesale dealer. The extraction of fluid hydrocarbons from bituminous substances, as shales, coals, and asphaltums, com menced in the latter part of the 17th century. In 1694 a patent was granted in England to Martin Eele, Thomas Hancock, and William Portlock for making pitch, tar, and oil out of shales. In 1716 a process was patented by the Bettons of Shrewsbury for making oil
from shales overlying the coal beds. They reduced the shales to powder by grinding, and employed the process of destructive distillation. The oil so extracted was used only for medicine, and called British oil. It was more than a century after this before much information was obtained in regard to the distillation of these oils, when baron Reichen bath investigated their properties, and called a mixture of several of the hydrocarbons in purified coal oils eupione. He discovered a great many new substances, and publish id an account of them in three different German scientific journals. Many patents were taken out by French and other inventors for methods of distilling these oils from coal and shales, and many conflicting claims to inventions and varying processes have arisen, which need not be discussed here. The discovery of petroleum in large quantities has practically put a stop to the manufacture of oils from shales or coal, and the name kero-* sene is now scarcely known to the trade, the term petroleum having taken its place either as crude or refined petroleum. See PETROLEUM and PETROLEUM PRODUCTS; also N.k.PuTtra, ante.