Oil of Worm′wood. Syn. Oleum absinthii,

L. From the fresh herb, as OIL OF LILIES. The P. Cod. and Ph. Wurtem. order only part of the herb to 8 parts of oil. Applied to the abdomen in dyspepsia, diarrhœa, heartburn, worms, &c. It is seldom used in this country.

OILS (Mineral). Syn. Hydrocarbon oils. An important class of liquids, consisting solely of carbon and hydrogen—the elements of ordinary coal-gas, and obtained by the distillation of coal, lignite, petroleum, and other bituminous substances. For the purposes of illumination, many of these oils are in most respects superior to the fixed or fat oils containing oxygen. They give a whiter and more brilliant light, and are produced at a much lower cost. The lamps in which they are burnt, when properly constructed, are less liable to get out of order than those adapted for the combustion of fat oils, and require less attention when in use. The experiments of Dr Frankland on the relative value of the ordinary illuminating agents[57] prove that the mineral oils are cheaper than all other portable illuminating agents in common use, and that they give, while burning, the largest amount of light with the least development of heat, and the smallest production of carbonic acid. With the oils adapted for burning in lamps other oils are produced. Some are very volatile and highly inflammable, and the safety of the burning oils depends on their proper extraction. These volatile liquids, when isolated, are used in the arts as substitutes for spirits of turpentine, as solvents for various substances, and to increase the illuminating power of coal-gas. Others are of a greasy nature, and are too heavy to be conveniently used in lamps. These, however, are well adapted for lubricating fine machinery, and are extensively employed instead of sperm oil by the cotton manufacturers of Lancashire. When the more volatile ingredients are separated from the burning oils, the latter are perfectly safe. Most of the mineral burning oils now in use are, we believe, free from danger in this respect. (See Tests, below.)

[57] See article Illumination.

Hist. For many years the manufacture of burning oils by the distillation of bituminous schists has been extensively carried out on the Continent, but the discovery which formed the foundation of the modern manufacture was made nearly thirty years ago by our countryman, Mr James Young. This gentleman took the lease of a spring of petroleum in 1847, and after numerous experiments succeeded in obtaining two useful oils from the crude liquid; the one being adapted for lubricating machinery, and the other for burning in lamps. The almost total cessation of the flow of petroleum terminated the business after two years’ working, and led Mr Young to institute a series of experiments to try if petroleum could be produced artificially by the destructive distillation of coal. These

experiments resulted in the discovery of an oil which Mr Young named ‘Paraffin oil,’ as it had many of the chemical properties of the solid body of paraffin, discovered twenty years before by Reichenbach in beech-wood tar. Young’s patent (dated Oct. 7, 1850) involved the slower distillation of coals, at a lower temperature than had hitherto been employed for the purpose, and this novelty in practice was followed by the novel result of a copious production of liquid hydrocarbons. The gas or cannel coals were found to yield the liquids in largest quantities, that variety known as Boghead coal or Torbane Hill[58] mineral being specially adapted for the patented process. (See Paraffin oil, below.) Soon after Young’s discovery native petroleum was brought from Rangoon, and purified by distillation, so as to produce oils very similar to the coal products. During the last few years, however, rich sources of petroleum have been discovered in North America, and from whence are imported the greater part of the vast quantities of petroleum oil (both for burning and lubricating purposes), together with the paraffin spirit, or naphtha, which are consumed in this country.

[58] This species of coal is now exhausted.—Ed.

In the following table are given the quantities of these substances sent into England and Scotland during the year 1875:—

Refined burning Oil.Lubricating Oil.Residuum.Petroleum Spirit.
Barrels.Cases.Barls. & Casks.Barrels.Cases.Barrels.
London169,7623,2502,5111,000...53,173
Liverpool95,8532,83030029,358...30,913
Hull20,2268............
Bristol36,8891,392.........17,203
Clyde and Leith4,23345359,387......
——————————————————
Total326,9637,4843,34639,745...101,289

This amounts to about 17 millions of gallons. In 1874 it exceeded 20 millions of gallons, but the stock in hand at the end of 1874 was about 5 millions of gallons, and the end of 1875 was only 11⁄2 million. The difference was mainly due to overtrading in 1874, which brought refined petroleum to the lowest price yet known in England, viz. 73⁄4d. per gallon in December, 1874, and checked its subsequent importation.[59]