114 THE POPULAR SCIENCE MONTHLY. 



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 West- 

 ern 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 sj^ecialty in oils. Thus, in Southern Russia, tobacco-oil is largely 

 used ; in Italy, oil of grape-stones ; in China, oil of tea-seed ; in In- 

 dia, oil of nutmegs, of seeds of the gamboge-tree, of custard-apple- 

 seed, of cashew-nut, of cardamom, of neam, of margoza, and many 

 others. Brazil, too, has a large number of oils, both animal and vege- 

 table, peculiar to itself. 



In this connection, and bearing in mind Lelyveld's essay on smooth- 

 ing the waves with tar-oil, we note that Great Britain annually imjDorts 

 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 attempt- 

 ing 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 over- 

 come the noxious smell of the various products ; so that this enter- 

 prise did not command large success. 



About the year 1847 Sir Lyon Play fair discovered a petroleum- 

 spring at Biddings, in Derbyshire, to which be 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 lubricat- 

 ing 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 parafiine- 

 candles, and these were lighted by Dr. Playfair, to illustrate the nov- 

 el 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 Derby- 

 shire 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 



