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To Bleach the Vegetable Oils

According to Cooley, almond, ben, castor, colza, linseed, nut, olive, poppy, rape, teel, and other like vegetable oils, are readily bleached by exposure, in glass bottles, to the light. For this purpose, 2-quart to 4-quart pale green glass or blue glass bottles filled with the oil, and covered with white gallipots inverted over them, are suitably placed, a small distance apart, on the roofs of houses or sheds, or in any other suitable position, fully exposed to the sun during the greater portion of the day, or at all events to the south-east and south. 14 to 21 days' exposure to the sun, in clear weather, during summer, In some cases a few drops of strong nitric is usually sufficient to decolor castor oil and acid (diluted with about twice its bulk of almond oil; but 4, 5, or even 6 weeks, is com- water), if added towards the end of the agimonly required to render linseed oil very pale. tation, will facilitate the process; or, with This is the common plan adopted by the colza, linseed, nut, and rape oil, instead of wholesale druggists to whiten their castor oil, by some of the perfumers for their almond oil and olive oil, and by the oilmen for their pale linseed oil for artists. A better plan, however, when this method is adopted, is to cork the bottles loosely air-tight, but not firmly down, when the sun has been on them two or three hours, and whilst they are still heated with it.

In this way the oil suffers less from the exposure than by the loose gallipot system in common use. Almond, olive, and the other sweet oils, thus treated, are apt to lose some the diluted nitric acid, a few drops of hydrochloric acid without dilution. After the final agitation, the oil must be allowed to repose at a temperature of about 60° Fahr. When it has settled, the clear portion should be decanted, thoroughly washed with hot water, again allowed to repose for some time, and then finally decanted for use. If necessary, it may lastly be filtered. (Cooley.) 1507. Berlandt's Method of Bleaching Fixed Oils. Shake strongly for some minutes, 300 parts of the oil with 40 parts renders the oil colorless. of their blandness, and to acquire a slight water containing 1 part permanganate of sulphurous smell, and smoky flavor, whilst potassa; allow the mixture to stand in a warm castor oil loses its original blandness, and as- place for some hours, and then filter. This sumes the strong, nauseous flavor characteristic of the white castor oil of the stores. These qualities may be removed by agitation with a little fresh animal charcoal, dry freshly prepared alumina, or calcined magnesia, and subsequent filtration; or, what is even better, 1508. Dieterich's Method of Bleaching Fixed Oils. Dissolve 24 pounds (avoirdupois) permanganate of potassa in 313 quarts water, in a wooden tub having a faucet in its bottom. Stir into the mixture 524 quarts though more troublesome, by well washing of the oil to be bleached, and keep all well the oil with hot water, and subsequent repose stirred for 2 days. Then add 21 quarts boilout of contact with the air, and subsequent ing water and 11 pounds commercial hydrodecantation. (See No. 1503.)