Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/806

Rh OILS only slowly on exposure to the air, and its chief applications are found in soap-making and for burning in lamps. It is principally produced and consumed in Germany and Russia. Grape-seed oil is used in the south of Germany and north of Italy for food and for burning in lamps. The seeds yield from 10 to 20 per cent, of a pleasant brownish-yellow very fluid oil, which dries very slowly on exposure to the air. Ground-nut oil (see GROUND NUT) is an excellent edible oil, largely used as a substitute for olive oil, and to no small extent passing into consumption either separately or mixed with olive oil under the name of the latter. The inferior hot-pressed qualities are employed in soap-making, being a principal staple of the soap industry of Marseilles, into which city not less than from 700,000 to 800,000 tons of the nuts are annually im ported from West Africa. Madia oil is obtained from the fruit of Madia sativa, a plant native of Chili, but introduced into Europe within this century on account of its oil-yielding properties. The seeds contain from 35 to 40 per cent, of a dark-yellow oil, of peculiar smell and mild taste, which has a tendency to become rancid. It has only faint drying properties, and occupies a place intermediate between drying and non-drying oils. When cold-pressed, madia oil may be used for food purposes, but it is principally consumed in lamps, or employed as a lubricant and in soap-making. Maize oil is a product of the seed-germs, which, in the preparation of maize meal and starch and fermented and distilled liquors from maize, have to be removed as carrying in them a disagreeable acrid substance. The germ contains about 15 per cent, of a clear golden- yellow oil, useful for burning, or oiling wool, and for lubricating machinery. Niger oil is the produce of the seeds (properly achenes) of Guizotia oleifera, a plant native of the east coast of Africa, but cultivated throughout India and to some extent in Germany. The fruits, which are small, tooth-like in form, and shining black in colour, contain from 40 to 45 per cent, of oil, which first came into the English market about 1851. The oil is limpid, clear, pale- yellow in colour, with a pleasant nutty mild flavour. It possesses little drying property, and is not fitted for use either in paints or varnishes. It is much used in India in the Deccan especially as a substitute for ghee with the poorer sections of the population, and in other parts of the country both as a culinary oil and for burning. In Western countries niger oil is principally employed in soap-making and as a lubricant. Nut oil is the produce in Europe of the nuts of the walnut tree, Juglans regia, and in America a similar oil is obtained from hickory nuts, Carya alba. The Euro pean walnut kernels yield from 40 to 50 per cent, of a fine limpid oil, which when cold -pressed is almost colourless, with a sweet nutty taste and pleasant odour, but the hot-pressed oil has a greenish- yellow colour and a rather sharp taste. Nut oil consists in large proportion of linolein, with olein and the glycerides of myristic and lauric acid. It is one of the most fluid of all oils, and, as it possesses with colourlessness strong drying properties, it is much valued by artists for oil-painting ; it also yields a fine transparent varnish. In the hilly districts of northern India and Persia the native regions of the walnut the oil is used for culinary purposes and for lighting. Several closely-allied nuts, both in Europe and in America, yield oil, similar in quality to that of the walnut. Para-nut or Brazil-nut oil, yielded by the kernels of Bcrtholletia excelsa, is employed in South America as a food-oil and for soap- making. To a limited extent it is also pressed in England and Germany from nuts which become unfit for table use. The oil be comes rapidly rancid. Sapucaia oil, yielded by Lecythis ollaria, also a South- American tree, allied to the Bcrtholletia, is analogous in properties and uses. Pine oils are got from the seeds of various species of pine and fir trees containing some proportion of resinous matter ; they have a turpentine odour and possess powerful drying properties. They are useful for mixing painters colours, for making varnishes, and for burning in lamps. Poppy oil is yielded by the seeds of the opium poppy (see OPIUM). In the valley of the Ganges, the great region of opium culture, the poppy seed is con sumed as an article of food by the native population, and, is their principal source of oil. The exceedingly minute seeds contain as much as 60 per cent, of a fine transparent, nearly colourless limpid oil, of pleasant taste and faint characteristic odour. The qualities obtained by cold and hot pressing respectively are distinguished from each other, the former being an esteemed salad oil, while the latter, of yellow colour, sharp taste, and linseed-oil-like odour, is used for soap -making, &c. Poppy oil consists principally of the glyceride of linoleic acid, linolein, and has therefore powerful drying properties, on which account it is much used by artists. To some extent the finer qualities are used for adulterating olive oil. Purging-nut oil is obtained from the seeds of Jatropha Curcas, a small tree native of India, but cultivated in tropical countries. It is a violent purgative, and contains, like castor oil, ricinoleic acid. It is comparatively limpid and odourless, and forms an excellent lamp oil. It is also used in the soap trade and as a lubricant. Safflower oil is yielded by the seeds (achenes) of the composite plant Carthamus tinctorius, which contain from 30 to 35 per cent, of a light-yellow clear limpid oil. It is extensively used in Egypt, the East Indies, and China (where the plant is cultivated as a source of the dye-stuff safflower), its principal applications being for culinary purposes and burning, and also as an ointment in para lytic affections and ulcers. A thick sticky charred oil is obtained from the seed in India by a process partly of burning and partly of distillation. The dark fluid so obtained is used by the native agriculturist for greasing leather-work exposed to the action of water. Sesame or Gingelly oil, one of the most highly esteemed of vege table oils, is the produce of Sesamum orientate. The plant is grown especially in India as an annual ; it ripens in about three months, and two crops are reaped yearly. The seeds are very small, weigh ing not more than one-tenth of a grain, and they vary in colour from a dirty white through brown to nearly black. They are highly oleaginous, containing as much as from 50 to 56 per cent, of a clear limpid oil of a pale-yellow colour, inodorous, bland and sweet of taste, and not liable to rancidity. It consists of about three parts of olein to one part of stearin and palmitin, with a small propor tion of the glyceride of myristic acid ; and it does not solidify till it reaches 5 C. Both seed and oil are of much importance in the East Indies and China as food substances. The seed itself is used directly as food ; the oil comes next to cocoa-nut fat in the variety and extent of its applications for food, personal use, and soap- making ; and the pressed cake is even an article of food among the poorer classes. As a salad oil the cold-pressed qualities are in every respect equal to the finest olive oil, its mild piquancy of taste causing it to be preferred by many. Indeed sesame oil may be used with advantage for every purpose to which olive oil is applied, excepting, probably, the Turkey-red dyeing, and it is in extensive consumption in food, lighting, soap -making, and as a lubricant. The oil is the subject of much adulteration, especially with the cheaper ground-nut oil. It can by itself, or as an adulterant of olive oil, be readily recognized by a peculiar green coloration it takes when shaken up with mixed sulphuric and nitric acids, a reaction peculiar to sesame oil. Sesame seed is principally crushed at Marseilles and Trieste, to which ports it comes partly from the Levant, but more largely from the East Indies and Java. The quantity of seed imported into France alone yearly is not less than from 70,000 to 80,0?0 tons. Sunflower oil is a clear pale -yellow limpid oil, with scarcely any smell and a mild pleasant character istic taste, obtained from the so-called seeds (achenes) of the sun flower plant, Helianthus annuus, which yield when freed from their husk about 30 per cent, of the oil. It contains glycerides of acids allied to linoleic acid, and possessing certain drying properties. It is of much importance in the east of Russia as an article of food, the sunflower being extensively cultivated in the government of Saratoff solely for its oil seed. Tea-seed oil is a commercial pro duct in China, where it is used for food, lighting, and soap-making. It is said to yield a fine hard soap. The oil contains 75 per cent, of olein and 25 parts of stearin, has a yellow colour, and is destitute of taste and smell. 2. Vegetable Fats. Among the numerous solid oils of the vege table kingdom only a very few occupy a place of great importance in Western commerce. Those which hold a foremost position palm oil, palm-nut oil, and cocoa-nut oil are referred to under their proper headings. Of the others the following enter more or less into general commerce. Dika butter is a solid fat yielded by the drupes of Irvingia Bartcri, a tree native of the Gaboon coast of Africa. The kernels are bruised and pounded into a cake, which is used by the natives for food as dika bread, and they contain more, than 60 per cent, of solid oil, which can be separated either by boil ing or by pressure with heat. It consists principally of glycerides of lauric and myristic acids, with only a little palmitin. Dika fat is used in soap and candle making. Chinese tallow is a white hard fat formed on the surface of the seeds of the tallow tree, Stillingia sebifera, native of China, but introduced into the North -West Provinces of India. The tallow is in China separated by steaming the seeds till they become soft, beating with stone mallets, and straining the mass through hot sieves. The fat melts at 44 5 C., and consists principally of palmitin with only a little olein. Chinese tallow has long been valued in China for making candles used in Buddhist worship, and it is now an article in English commerce, being imported for candle and soap making. The seeds themselves, after separation of the fat, yield an oil fluid at ordinary temperatures. Carapa (or Crab-wood) oil is a soft white fat obtained from the seeds of Carapa guyanensis, a tree native of Brazil and Guiana and of the west coast of Africa. A similar fat is also ex pressed from the seeds of the allied C. moliicccnsis, from the coasts of India and Ceylon. The fat has a slightly aromatic odour and a powerfully bitter taste, said to be due to the presence of strychnine. It is imported into the European markets for soap-making, and in its native regions it possesses a great reputation as an ointment in rheumatic affections. Piney tallow is a hard solid fat obtained from the seeds of the Indian copal tree, Valeria indica. The substance has a feeble but pleasant smell, and a slightly yellow colour ; it melts at 36 5 C., and consists of three parts palmitin and one part olein. It is prized for candle -making on account of the pleasant odour given off by the glowing wick. Cofcum butter is a solid white or greenish-yellow, pleasant-smelling, rather friable fat obtained from