(Fa. Huile de luvias, de Chdtaignes, de Castanheiro.)—The castanha or Brszil-nut (see Nuts, p. 1351) is very rich in oil ; each fruit contains some 20 nuts, and each lb. of nuts gives 4 T 2 10 oz. of oil. This is extracted by roasting the nuts, and pounding, pressing and draining the kernels. A superior product is obtained from the unroasted nuts. It is bland, pleasant, and of clear-yellow colour, and, in composition, differs but little from fixed almond-oil, which it resembles in its tendency to become rancid when kept. This last property renders it applicable only to illuminating, perfumery, and soap-making, for which it is well adapted. It is used for culinary purposes when fresh. It could be furnished in considerable quantities.
Castor-oil (FE., Huile de Castor, de Mein, de Palma-Christi; GEE., Ricinussarnen61).—The castor oil-plant, or Palma-Christi, as it is often called, belongs to the genus Ricinus, of which some 16 forms are distinguished, but all usually considered mere varieties of B. communis. The variety known as B. spectabilis is said to give 22 per cent. more oil. The plant is indigenous to India, whence it has been distributed by cultivation throughout all the tropics, and in many temperate countries. It flourishes in India, China, Java ; the Azores, and the W. African coast ; the Mediterranean region (Algeria, Egypt, Greece, Spain, Crete, Sicily, and the Riviera) ; France, Germany, and England ; Brazil, Spanish America, and the Portuguese colonies ; the United States and the W. Indies; and in good summers, ripens its seed as far north as Christiania, in Norway. In the most favourable situations, it attains a height of 40 ft. ; in the S. States of America, often 20-25 ft.; in the Mediter ranean region, 10-15 ft.; in India, 8-10 ft. ; in N. Europe, 4-5 ft.
The plant is probably most extensively grown in India, not only for the oil yielded by its seeds, but also on account of its leaves forming the food of some kinds of silkworm. Its cultivation is carried on in most parts of India. The whole of the N.-W. Provinces produce castor-oil, but inferior in quality to that obtained from the coast-grown seed of Coconada and that of Colcong. The plant might be raised much more extensively in Oudh. In Cuttack, it occupies much newly-cleared land, in the jungles of the Tributary States and Sumhulpore. Madras Presidency is reckoned to have 67,000 acres under this crop, chiefly in Coimhatore. Scarcely any cultivation is required, and the plant is frequently grown as a border for more valuable or delicate crops, especially as all insects are said to avoid it. It prefers a sandy loam, and will not thrive on clay. It attains full perfection as a hedge-plant, and flourishes well on newly-cleared jungle-land. Two kinds of the plant are distinguished by Indian native cultivators, a large-seeded and a small-seeded. Both are raised from seed, which is sown twice annually, in November and May. The natives sow and
uproot the plant every year, though it grows and yields abundantly in the second and third years in open spaces. When growing it alone, they almost always sow too thickly, and thus prevent the proper development of the plant. The operation of gathering the seeds is tedious. The two kinds are kept distinct, the oil obtained from the small-seeded sort being esteemed much superior. Separate methods of extraction are also adopted.
The seeds of the small-seeded variety are treated as follows. Having been sifted clear of all dirt and foreign matters, while still fresh, they are slightly crushed between two rolls, then freed by hand from husks and coloured grains, enclosed in clean gunny-sacks, and lightly pressed in oblong moulds to form " bricks " of uniform shape and density. These bricks are placed alternately with sheet-iron plates in an ordinary press, and the escaping oil is caught in clean tinned pans. To each I gal. of oil, is added 1 pint of water, and the whole is boiled till the water has evaporated ; the result of this is that the mucilage subsides, and encrusts the bottom of the pan, while the albumen solidifies, and forms a white layer between the oil and the water. The utmost care is necessary to remove the pan from the fire the moment the evaporation of the water is complete, as known by the cessation of bubbling ; if allowed to remain longer, the temperature, hitherto that of boiling water, 100° (212° F.), suddenly rises to that of boiling oil, 315i° (600° F.), thereby deepening the colour and developing an empyreumatic odour and flavour. The oil is filtered through blanketing or similar fabric, and put into canisters for export. It is known as " cold-drawn " oil, and is usually of a light-straw to greenish colour. The cleaned seeds yield 47-50 per cent. of oil by this method, fit for the European market. Experiments with Calcutta seed resulted in a product of 324 lb. 1st class oil, 87* lb. 2nds, and 76*1b. 3rds, or a total of 488 lb. of oil from 1400 lb. of seed (980 lb. of kernels) ; 1400 lb. of Madras seed gave 318 lb. lsts, 88 lb. 2nda, and 74 lb. 3rds, total 480 lb. The cost of the Madras oil, including the seed at R. 3.3 per bag of 164 lb., husking and selecting the kernels, crushing, moulding, pressing, boiling, filtering, overseers' pay, godown rent, 300 empty quart bottles, corks, cleaning, packing-charges, and sundries, was 76 rupees 1 anna, or an average of 4.06 annas per qt. of 1st, 2nd, and 3rd oil, or 4d. a lb. A second Indian method of exhausting this kind of seed is by hot-water extraction. The seeds are boiled in water for 2 hours, sun-dried for 3 days, shelled, pounded, and boiled in fresh water till the whole of the oil has risen to the surface. The yield is 1 qt. of oil from 3* lb. of seed. It is straw-coloured, free from unpleasant odour and flavour, and is commonly used by native medical practitioners.