1503. To Purify and Sweeten Castor Oil

1503.    To Purify and Sweeten Castor Oil. The American Journal of Pharmacy gives the following receipt for this purpose: Take 1000 parts of the oil, 25 parts purified bone-black, 10 parts calcined magnesia. Mix them carefully in a convenient vessel of glass or tinned iron, and let it stand during 3 days, with occasional agitation, and filter through paper or felt. (See No. 1504 (To Bleach the Vegetable Oils)).

1504. To Bleach the Vegetable Oils

1504.    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, is usually sufficient to decolor castor oil and almond oil; but 4, 5, or even 6 weeks, is commonly required to render linseed oil very pale. This is the common plan adopted by the 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 Unseed 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 of their blandness, and to acquire a slight sulphurous smell, and smoky flavor, whilst castor oil loses its original blandness, and assumes 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, though more troublesome, by well washing the oil with hot water, and subsequent repose out of contact with the air, and subsequent decantation. (See No. 1503 (To Purify and Sweeten Castor Oil).)

1505. To Bleach Vegetable Oils

1505. To Bleach Vegetable Oils. Another method pursued for bleaching oils is as follows: The oil is placed in a porcelain, stoneware, or well-tinned vessel, along with some dry filtering powder, 1 to 2 pounds to each gallon of the oil, or some dry and recently prepared hydrated alumina (1/4 to 1/2 pound per gallon of oil; but much less is often sufficient if the article be of proper quality); and the heat of steam or boiling water being applied, is vigorously stirred, with a clean wooden or stoneware spatula, for about an hour. It is then thrown into a Canton flannel oil-bag, and filtered, in the usual manner, observing to return the runnings until they become quite white and clear. This is the way perfumers and wholesale druggists usually prepare their white almond oil, white olive oil, and white oil of ben. Formerly fresh burnt animal charcoal was chiefly used for the purpose, and is still so employed by some houses; but the other substances answer better and are more convenient. (Cooley.)