Excellent oil is expressed in various parts of India from the seeds of different species of Sinapis, especially from the black mustard seed. S. glauca, S. dichotorna, and S. juncea are extensively cultivated in the East for their oil. The Erysimum perfoliatum is cultivated in Japan for its oil-seeds.
A beautiful pale yellow oil is procured from the seeds of the angular-leaved physic nut, Jatropha curcas, a shrub which is often employed in the tropics as a fence for enclosures. It is used by the natives in medicine and as a lamp oil. About 700 tons of this oil was imported into Liverpool in 1850 from Lisbon, for the purpose of dressing cloth, burning, &c.
A rich yellow oil, perfectly clear and transparent, is obtained from the seeds of Bergera koenigii.
RAPE OIL.—The imports of rape oil, from Brassica napus, into Liverpool, are about 15 to 20 tuns annually.
Rape oil has been found to be better suited than any other oil for the lubrication of machinery, when properly purified from the mucilage, &c., which it contains in the raw state. Rape oil is now used extensively for locomotives, for marine engines, and also for burning in lamps. It is stated that a locomotive consumes between 90 and 100 gallons of oil yearly; and the annual consumption of oil by the London and North-Western Railway, for this purpose alone, is more than 40,000 gallons. The oil obtained from good English rape seed is purer and of superior quality to that from foreign or colonial seed; and as an acre of land yields nearly five quarters of seed, which is worth at present 50s. per quarter, it is a profitable crop.
Rape seed is now largely imported for expressing oil. The imports, which in 1847 were but 87,662 quarters, weighing 17,532 tons, had reached, in 1851, 107,029 quarters, weighing 21,606 tons. The price of new seed is £25 to £27 the last of ten quarters. The oil is £34 per tun.
The refuse cake, after the seed is crushed for oil, is in demand as food for cattle, being worth £4 the ton.
We imported in 1851, from Trance, 289 tuns of rapeseed oil, worth about £17,000, on which there was no duty levied.
There are exported annually from Hesse Darmstadt, 34,660 cwts. of poppy and rape oils.
The oil of the colza is much used in Europe, and highly prized. In France it has been adopted for all the purposes of lighthouses. In this country it has lately come into extensive domestic use, for burning in the French moderateur lamps, being retailed at from 3s. 4d. to 4s. the gallon.