BASRA.
The liquid vegetable oils are very numerous, and several are of great commercial importance. First in rank is olive oil, made from the ripe fruit of the common olive (olea Europea). When good and fresh, it is of a pale greenish-yellow color, with scarcely any smell or except ti nutty flavor, inunlyeSteemed.by'those who use it.
The finest qualities are the Provence oil (rarely seen in Britain), Florence oil, and Lucca oil. These are all used for salads and for cooking. The Genoa is used on the continent fur the stone purposes; and Galipoli, which is inferior, constitutes the great bulk of what is received in this country for cloth dressing, Turkey-red dyeing, and other purposes; the continental soap-makers also employ it extensively. The high price of the best qualities leads to much adulteration with poppy and other oils, but it is generally pretty safe when in the original flasks as imported. The mode of obtaining the finest kinds i4 by gentle pressure of the fruit. The cake is afterwards treated whir hot water, from the surface of which an inferior is skimmed. The Galipoli oil is obtained by allow ing the olives to ferment in heaps, and then to press them in powerful oil-presses; the cake or mare is then treated with water once or twice, until all the oil is removed; this inferior oil is darker in color. being a yellowish or brownish green. We receive the finest from Italy, and the commoner qualities from the Levant, Mogador. Spain, Portu gal, and Sicily. The present values range from £44 to £54 for common kinds, and the finest Lucca is £1 the half-chest, or nearly £85 per tun measure. The total quantity imported during the four years 1872-75 was as follows: 1872, 23,964 tuns; 1873, 35,121 tuns; 1874, 22,720 tuns; 1875, 33,453 tuns.
Nearly all the other liquid vegetable oils of this class are obtained from seeds, and as they are most of them treated in the same way, one description will suffice. First, tne seeds are ground—and this in Britain is always clone by vertical stones (see MILL)—into a kind of coarse meal, which is first warmed in pans, and then put in certain portions in woolen cloths or bags, so arranged as to he of uniform thickness; these are aga:n wrapped in horse-hair cloths, and each parcel is placed between two flat boards slightly fluted on their inner sides, and then placed in the wedge press. In thisa, a are two flannel bags filled with the meal and inclosed in horse-hair bags, each flattened between the flat boards, b, b, b, b. They are set upright, between the pressing-plates, 1,
one at each end of the press-frame, ccc, which is made of great strength, and often of cast-iron. Next is placed the wedge d; the other wedge, e, is then suspended by a cord in the position represented; h, h. are then placed, as seen in the drawing; the main wedge, g, is lastly inserted, and the press is ready for action. The operation is very simple; a heavy wooden stamper, from 500 to GOO pounds weight, is raised by machinery about two feet, and allowed to fall upon the wedge g. This tightens all the other wedges and pressing-plates, and exerts a pressure of about 60 tons on each bag when fully driven home. The pressing-plates, 1, 1, 1, i, are pierced with holes, and so arc the plates b, b, b, b; and through these holes the oil trickles and passes away through a pipe at the bottom.
One of the chief seed oils is that of linseed (q.v.). Very little linseed oil is imported Into Britain; the improved machinery, and the great demand for the oil-cake (see °li mier.), causes it to be manufactured at home, and at present it is exported in consider able quantities; thus, from Hull alone there was exported in 1S75, of seed-oil, expressed chiefly from foreign seed, no less than 6,846,725 gallons, and over 10,000 tons of oil cake; and from London and Liverpool together about the same quantity. The total pro duction of Great Britain for 1868 was estimated at 65,000 tons;' for 1809, 61.000 tons; for 1871, 69.000 tons; and for 1872, 67,000 tons. In 1875, 15,628,316 gallons of seed-oil were exported. It is worth about £30 per ton. Rape or colza oil is a name which covers the product of several eruciferions seeds, as rape, turnip, and other species of brassica, rad ish. sinapis feria, gold of pleasure, etc. The oil is clear brown and usually sweet, hut with a mustard-like flavor; its illuminating powers are excellent, and it is also well adapted for wool-dressing. Very large quantities are made in Great Britain, from sinapis feria and other Indian mustard seeds, which are imported under the name of Surzee seed. The imports of these seeds are occasionally as touch as 60,000 quarters per annum. Ilemp seed yields a green oil which is much used in making soft soap, especially in Holland. In Russia it is eaten with various kinds of fond, and is greatly liked by all classes.