1471. Oil of Quince - Pelargonic Ether

1471. Oil of Quince - Pelargonic Ether - is made from oil of rue by treating it with double its volume of dilute nitric acid, heating the mixture until it begins to boil. After some time two layers are seen. The lower one is separated with a pipette, and freed from nitric acid by evaporation in a chloride of zinc bath; it is then filtered, mixed with deodorized alcohol, and digested at a gentle heat until the fruity odor is noticed. This ether seems identical with the ethereal oil of wine, which gives the bouquet. It is sometimes sold as oil of cognac.

1472. To Restore the Fragrance of Oil of Lemon

1472.    To Restore the Fragrance of Oil of Lemon. There are several oils that, by absorption of oxygen from the air, will become camphorated, grow turbid, deposit a residue, generally called stearopten, and lose more or less of their flavor, instead of which they acquire the odor of turpentine. Those oils that are free from oxygen are chiefly subject to these changes, and it is therefore necessary to keep them in full bottles, well stoppered, and in a cool place. When they have deteriorated in the way indicated, they may be improved, but can never be restored to their original quality. Many means have been proposed for this purpose, but the one now generally employed in France is to shake the oil with warm water several times, letting it settle, and drawing it off by means of a syphon; it may lastly be filtered either through paper or linen.

1473. To Keep Oil of Lemon Fragrant

1473.    To Keep Oil of Lemon Fragrant. To every pound of oil, 1 ounce alcohol is to be added and well mixed; then 1 ounce water is put with it, which again withdraws the alcohol from the oil, and collects at the bottom of the bottle as dilute alcohol, where it should be permitted to remain until the oil has been used, with, perhaps, an occasional shake-up when the bottle has been opened. Oil of lemon treated in this manner has been kept fresh and fragrant for over a year. Oil of orange may be treated in the same manner with excellent effect.

1474. To Purify Essential Oils that have Deteriorated from Age

1474.    To Purify Essential Oils that have Deteriorated from Age. The method most commonly pursued is by redistillation, mixing them first with water, and sometimes with alkali. There are, however, other processes that have been recommended, which are believed to be equally as efficacious, and at the same time more simple. M. Curieux proposes to submit them to the action of a solution of borax with animal black. The solution of borax is mixed with the animal charcoal to form a thin consistency; the oil is then added and agitated for a quarter of an hour. At the end of that time the borax mixture is found adhering to the sides of the bottle, while the oil flows limpid. The oil of lavender, neroli, and peppermint, M. Curieux had restored or purified in this manner. Mr. Charles Bullock, of Philadelphia, has found that permanganate of potash is admirably adapted to the purpose of the restoration of resinified essential oils. A large can of oil of lemon having become unsaleable, he agitated a solution of the potash with the oil for a length of time, then decanted, mixed with fresh water, and warmed gently, till the oil floated perfectly clear on the surface. The solution of the permanganate was in the proportion of 1 ounce of the salt to 8 ounces of water. This quantity was enough for 4 pounds of the oil.