To make Oil of Sweet Almonds
It is usually made from bitter almonds for cheapness, or from old Jordan almonds, by heat, the oil from which soon grows rank, while that from fresh Barbary almonds, drawn cold, will keep good for some time. The almonds are sometimes blanched by dipping in boiling water, or by soaking some hours in cold water, so as to part with their skin easily, but are more usually ground to a paste, which is put into canvas bags, and pressed between iron plates in a screw press, or by means of a wedge, 1 cwt. of bitter almonds, unblanched, produces 46 lbs. of oil; the cake pays for pressing.
Is obtained from the kernel of the hazelnut, and is very fine. As it will keep better than that of almonds, it has been proposed to be substituted for that oil. It is drunk with tea in China, probably in lieu of cream, and is used by painters, as a superior vehicle for their colors.
Oil of Mace
Is obtained from nutmegs by the press. It is buttery, having the smell and color of mace, but grows paler and harder by age; 2 lbs. of nutmegs in Europe will yield 6 oz. of this oil.
True Oil of Mace by Expression
This oil is red, remains always liquid or soft, has a strong smell of mace, subacid taste, and is imported in jars or bottles, the lower part being rather thicker than the top; 1 1/2 lbs. of mace will yield in Europe 1 1/2 oz. troy of oil.
Olive, Salad, or Sweet Oil
This is the most agreeable of all the oils; it is demulcent, emollient, gently laxative, and is also used as an emetic with warm water; dose, 1 oz. troy, or a large spoonful; also externally, when warm, to the bites of serpents, and, when cold, to tumors and dropsies. Rank oil is best for plasters, but fresh oil makes the best hard soap.
Is made by pressing the beans, cold or slightly warmed. It may be rendered colorless and odorless by filtering through animal charcoal and magnesia. It is soluble in strong alcohol, and is used as the basis of many hairoils.
Oil of Croton
This oil is extracted from Molucca grains, or purging nuts. In its chemical qualities it agrees with castor oil, but is considerably more active, as a single drop, when the oil is genuine, is a powerful cathartic.
This is made from rape-seed. It dries slowly and makes but a softish soap, fit for ointments. The mucilage it contains may be got rid of, in a great measure, by adding 1/2 ounce of oil of vitriol to 2 pts. of the oil.
To Purify Rape Oil
The following is a simple method of rendering rape oil equal to spermaceti oil, for the purposes of illumination: Begin by washing the oil with spring-water; whicb is effected by agitating the oil violently with a sixth part of the water. This separates the particles of the oil, and mixes those of the water intimately with them. After this operation it looks like the yolk of eggs beat up. In less than 48 hours they separate completely, the oil swimming at the top, the water, with all feculent and extraneous particles, subsiding to the bottom. This may be very much improved, by substituting sea water in the place of fresh-water.
By the process of washing the oil does not lose a hundredth part. The experiment can at all times be made in a glass decanter, or in a churn, with a cock at the bottom, the water to come up very near to the cock, by which all the oil can be drawn off, after it has deposited its impurities.
To 100 parts of oil add 1 1/2 or 2 of concentrated sulphuric acid, and mix the whole well by agitation; when the oil will become turbid, and of a blackish-green color. In about three-quarters of an hour the coloring matter will begin to collect in clots; the agitation should then be discontinued, and clean water, twice the weight of the sulphuric acid, be added. To mix the water with the oil and acid, a further agitation of half an hour will be requisite. The mass may, afterwards, be left to clarify for 8 days, at the end of which time 3 separate fluids will be perceived in the vessel; the upper is the clear oil, the next is the sulphuric acid and water, and the lowest a black mud or fecula. Let the oil then be separated by a syphon from the acid and water, and filtrated through cotton or wool. It will be nearly without color, smell, or taste, and will burn clearly and quietly to the last drop.
To Purify Vegetable Oil
To 100 lbs. of oil add 25 oz. of alum, and mix, dissolved in 9 lbs. of boiling water. After stirring it about half an hour, add 15 oz. of nitric acid, still continuing to stir it. Let it stand 48 hours, when the fine oil will swim on the surface, and then draw it off. Such oil is used all over the Continent, and an equal quantity yields double the light of whale and fish-oil without its offensive odor.
To make Pumpkin Oil
From the seeds of the pumpkin, which are generally thrown away, an abundance of an excellent oil may be extracted. When peeled they yield much more oil than an equal quantity of flax. This oil burns well, gives a lively light, lasts longer than other oils, and emits very little smoke. It has been used on the Continent for frying fish, etc. The cake remaining after the extraction of the oil may be given to cattle, who eat it with avidity.
Beech Nut Oil
Beech-nuts are not only an excellent food for pigs, but they are known to yield an oil, fit for common purposes, by the usual methods of extraction.
Animal Oils And Fats[edit | edit source]
This is obtained like the rest of the animal fats, from the raw lard, by chopping it fine, or rather rolling it out, to break the cells in which the fat is lodged, and then melting the fat in a waterbath, or other gentle heat, and straining it while warm. Some boil them in water, but the fats thus obtained are apt to grow rank much sooner than when melted by themselves.
Neat's-foot or Trotter Oil
Obtained by boiling neat's-feet, tripe, etc. in water. It is a coarse animal oil, very emollient, and much used to soften leather. To Purify Trotter Oil
Put 1 qt. of trotter oil into a vessel containing 1 qt. of rose-water, and set them over a fire till the oil melts and mixes with the rose-water. Stir well with a spoon. When properly combined take the vessel from the fire, and let it cool. Now take off the oil with a spoon, and add rosewater as before. When the oil is again separated and cleansed, set it in a cool place. The principal use of trotter oil is for the making of cold cream, in which its qualities exceed those of every other oil.
To Prepare Oil from Yolks of Eggs
Boil the eggs hard, and after separating the whites break the yolks into 2 or 3 pieces, and roast them in a frying pan till the oil begins to exude, then press these with very great forge. Fifty eggs yield about 5 oz. of oil. Old eggs yield the greatest quantity. Another Method
Dilute the raw yolks with a large proportion of water, and add spirit of wine to separate the albumen, when the oil will rise on the top after standing some time, and thus may be separated by a funnel.
To Bleach and Purify Fixed Oils
Fish and other fat oils are improved in smell and color by passing hot air or steam through them. Dunn's method is to heat the oil by steam to 170o or 200o, and force a current of air through it, under a chimney, till it is bleached and purified. Mr. Cameron's method of bleaching palm oil is to keep it at 230o, with continual agitation, by passing into it high pressure steam through leaden pipes of 2 inches diameter. Four tons of oil require 10 hours' straining. Palm oil is also bleached by chloride of lime. Take from 7 to 14 lbs. of chloride of lime, triturate in a mortar, adding gradually 12 times the quantity of water, so as to form a smooth cream. Liquefy 112 lbs. of palm oil, remove it from the fire, add the solution of chloride of lime, and stir well with a wooden stirrer. Allow it to cool, and when become solid break it into small fragments, and expose it to the air for 2 or 3 weeks, then put into a castiron boiler lined with lead, diluted with 20 parts of water.
Boil with a moderate heat till the oil drops clear from the stirrer; then let it cool. To remove the foetor from fish oils, treat them in the same way (except the exposing to the air), using only 1 lb. of chloride of lime to 112 lbs. of oil, It does not remove the natural smell of the oil. Calcined magnesia has been used to deprive oils of their rancidity.
Mr. Griseler finds that the addition of a few drops of nitric ether will prevent oils from becoming rancid.
Mr. Watt's patented method of bleaching oil is by chromic acid. For palm oil it is thus used: The oil is heated in a steam vessel, allowed to settle and cool down to 130o Fahr., then removed into wooden vessels, taking care that no water or sediment accompany it. For a ton of palm oilmake a saturated solution of 25 lbs. of bichromate of potash; add 8 lbs. of sulphuric acid, and 60 lbs. of muriatic acid (or an equivalent quantity of salt and sulphuric acid). Put the mixture into the oil, and let it be constantly stirred till it becomes of a light-green color. If not sufficiently decolored, add more of the mixture. Let the oil settle for half an hour, then pump it into a wooden vat, boil it for a few minutes with fresh water, by means of a steam pipe, and let it settle. For linseed, rape and mustard oils a dilute solution of chromic acid is used, with a little muriatic acid; for olive, almond, and castor oils no muriatic acid is required. Fish oils and fats are first boiled in a steamapparatus with a weak soda lye (1/2 lb. of soda for every ton of fat) for half an hour; then 1/2 lb. Of sulphuric acid, diluted with 3 lbs. of water, is added, the whole boiled for 16 minutes, and allowed to settle for an hour or more, when the water and sediment are drawn off, and the oil further bleached by a solution of 4 lbs. of bichromate of potash and 2 lbs. of sulphuric acid, properly diluted.
Mr. Davidson treats whale oil first with a solution of tan, next with water and chloride of lime, and lastly with diluted sulphuric acid and warm water. Rape and other seed oils are also refined by means of sulphuric acid and twice as much water. Mr. Gray directs 2 lbs. of oil of vitriol to 112 lbs. of oil. The oil should be carefully washed from the acid and filtered.
Mr. Bancroft's process for refining common olive oil, lard oil, etc., for lubricating purposes, is to agitate them with from 3 1/2 to 8 per cent. of caustic soda lye, of 12 specific gravity. If, on trial of a small quantity, the lye he found to settle clear at the bottom, enough has been added. The oil is allowed to rest for twenty-four hours for the soapy matter to subside: the supernatant oil is then filtered.
Another plan of purifying oils (especially lamp oils) is to agitate them with a strong solution of common salt.
Purification of Castor Oil
Mix 1000 parts of the oil with 25 parts of animal charcoal, and 10 parts of calcined magnesia, and leave them together for 3 days at a temperature of 68o to 78o Fahr., often stirring or shaking the mixture. The oil is then filtered off, and is found to be limpid, colorless, without taste, and easily soluble in alcohol. It congeals, too, at a lower temperature than before, and is in that respect superior to the ordinary oil.
Oil of Brick
Used by lapidaries, is made by saturating fragments of brick with oil and distilling at a red heat.
- Expose the finest porpoise oil to the lowest natural temperature attainable. It will separate into two portions, a thick, solid mass at the bottom, and a thin, oily supernatant liquid. This is to be poured off while at the low temperature named, and is then fit for use.
- Put into a matrass or glass flask, a portion of any fine oil, with 7 or 8 times its weight of alcohol, and heat the mixture almost to boiling; decant the clear upper stratum of fluid, and suffer it to cool; a solid portion of fatty matter separates, which is to be removed, and then the alcoholic solution evaporated in a retort or basin, until reduced to one-fifth of its bulk. The fluid part of the oil will be deposited. It should be colorless and tasteless, almost free from smell, without action on infusion of litmus, having the consistence of white olive oil, and not easily congealable.
- Take a white glass bottle of pure olive or almond oil, put into it a coiled strip of lead, and expose it to the sun's rays until a white curdy matter ceases to be deposited.
To Prevent Fats and Oils from becoming Rancid
Heat the oil or melted fat for a few minutes with powdered slippery-elm bark, in the proportion of 1 dr. of the powder to 1 lb. of fat. The bark shrinks and gradually subsides, after which the fat is poured off. It communicates an odor like that of the hickory-nut. Butter thus treated has been kept unchanged for a year. 482