Page:Popular Science Monthly Volume 26.djvu/124

114 valued at £1,600,000. The export of seed-oil from London, Hull, and Liverpool, in 1880, was 14,508,000 gallons.

Under the head of seed-oils rank linseed, cotton-seed, and castor oil. Colza-oil, also, is made from mustard, hemp, radish, rape, turnip, and other seeds. Then we have olive-oil and almond-oil. From India comes poppy-seed oil; from the Black Sea, oil of sunflower-seeds. From Ceylon and the Pacific isles comes cocoanut-oil. From Western Africa the palm-nut oil of the oil-palm, and oil of ground-nuts, for use in fine machinery. From Singapore and China we receive kokum-oil and vegetable tallow. About fourteen thousand tons of croton-oil are annually imported for the use of the wool-dressers of Britain.

Besides these, so familiar to ourselves, almost every country has some specialty in oils. Thus, in Southern Russia, tobacco-oil is largely used; in Italy, oil of grape-stones; in China, oil of tea-seed; in India, oil of nutmegs, of seeds of the gamboge-tree, of custard-appleseed, of cashew-nut, of cardamom, of neam, of margoza, and many others. Brazil, too, has a large number of oils, both animal and vegetable, peculiar to itself.

In this connection, and bearing in mind Lelyveld's essay on smoothing the waves with tar-oil, we note that Great Britain annually imports five million gallons of wood-tar, and that about an equal quantity is made in the country from coal, at the charcoal-works, the gas-works, and the bone-factories.

To M. du Buisson, a Frenchman, is due the credit of first attempting to distill oil fit for burning from the bituminous shales hitherto deemed worthless. He succeeded in his experiment, but the shales of France were not found to yield oil in paying quantities. An effort was then made to apply the same process to the bituminous shales of Dorsetshire, and "Kimmeridge coal" was found to yield a much larger proportion of oily matter. It was, however, found impossible to overcome the noxious smell of the various products; so that this enterprise did not command large success.

About the year 1847 Sir Lyon Play fair discovered a petroleum spring at Riddings, in Derbyshire, to which he called the attention of Mr. James Young, a Manchester chemist, who proceeded to distill it, thereby obtaining a clear, thin burning-oil, and also a thick lubricating oil. Certain solid crystals floating in the petroleum suggested the presence of paraffine, and the possibility of obtaining a candle-making substance. This resulted in the manufacture of the first two paraffine candles, and these were lighted by Dr. Playfair, to illustrate the novel subject at a lecture to the Royal Institution, when he foretold that ere long they would become the common light of the country—a prophecy which was very quickly realized, but not from the Derbyshire springs, as these were soon exhausted.

Mr. Young's attention was next attracted by seeing oil dripping from the roof of a coal-mine, which led to further experiments, with