Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 83

The solution of a few grains of benzoic acid, or of gum benzoin (preferably the first), in any of the above oils, will materially r.e.t.a.r.d the accession of rancidity, if it does not prevent it altogether.

The oils of the last two cla.s.ses (2 and 3) are chiefly used to impart their respective odours to the simple oils, pomades, &c.; and in the manufacture of scented spirits or esprits. The following formulae are given as examples of both cla.s.ses of preparations:--

=Oil of Am'bergris.= From ambergris, 2 dr.; oil, 1 pint; by infusion.

=Oil of Ben'zoin.= From gum benzoin, 7 dr.; oil, 1 pint; by infusion.

=Oils for the Hair.= _Syn._ HUILES ANTIQUES, Fr. These are numerous. All those scented with the simple perfumes are prepared in the way explained under cla.s.s 1 (_above_). The selection depends entirely upon the judgment of the operator or the fancy of the purchaser. In general, a mixture of two or three perfumes is preferred in these countries to the pure fragrance of any single flower, and a grossness of taste is exhibited in these matters which surprises our Continental neighbours, and the inhabitants of Italy more particularly. Some of these oils are coloured. A red tinge is given to them by allowing the oil to stand for a few hours over a little alkanet root (2 dr. to the pint) before scenting it. The application of a gentle heat facilitates the process. Yellow and orange are given by a little annotta or palm oil; and green, by steeping a little green parsley or lavender in them for a few days; or by dissolving 2 or 3 dr. of gum guaiac.u.m in each pint by the aid of heat, and, when cold, decanting the clear portion. Huile antique au jasmin, Huile antique a la fleurs d'oranges, Huile antique a la rose, Huile antique a la tuberose, Huile antique a la violette, &c., are simple oils flavoured with the respective perfumes or their preparations.--Huile antique rouge a la rose is the ordinary oil of roses coloured with alkanet root.--Huile antique verte is simple oil coloured green, as above, and scented.--Huile antique aux millefleurs is so scented with several perfumes that none predominate.

A mixture of bergamotte, lemons, lavender, neroli, pimento, and ambergris or musk, is commonly employed for the purpose.

=Oil, Macas'sar.= _Syn._ HUILE DE MACa.s.sAR. _Prep._ 1. (Rowland's.) Oil of ben or almonds (reddened by alkanet root), 1 pint; oils of rosemary and origanum (white), of each 1 dr.; oil of nutmeg and attar of roses, of each 15 drops; neroli, 6 drops; essence of musk, 3 or 4 drops.

2. (De Naquet.) Oil of ben, 1 quart; nut oil, 1 pint; rectified spirit, 1/4 pint; essence of bergamotte, 3-1/2 dr.; tincture of musk and esprit de Portugal, of each 2 dr.; attar of roses, 1/2 dr.; alkanet root, q. s. to colour.

=Oil, Mar'row (Perfumed).= 1. Simple marrow oil, scented at will.

2. (FLUIDE DE JAVA.) Marrow oil, coloured with a little palm oil and scented.

3. (HUILE COMOGENE.) Marrow oil, 4 oz.; spirit of rosemary, 1-1/2 oz.; oil of nutmeg, 12 drops.

4. (HUILE PHILOCOME D'AUBRIL.) Cold-drawn nut oil and marrow oil, equal parts; scent at will, q. s.

5. (HUILE DE PHeNIX.) Clarified beef marrow, lard, pale nut oil, and expressed oil of mace, of each 4 oz.; melt together by the heat of hot water, strain through linen into a warm stone mortar, add, of oils of cloves, lavender, mint, rosemary, sage, and thyme, of each 1/2 dr.; rectified spirit, 1 oz., in which has been dissolved by a gentle heat balsam of tolu, 4 dr.; camphor, 1 dr.; triturate until the whole is cold, and then put it into bottles. All the above are used to make the hair grow, and to prevent it falling off.

=Oil of Musk.= From grain musk, 1 dr.; ambergris, 1/2 dr.; oil of lavender, 20 drops; oil, 1 pint, by infusion. A second quality is made by working the same ingredients, after the oil is poured from them, with 3/4 pint of fresh oil. This also applies to OIL OF AMBERGRIS and HUILE ROYALE.

=Oil of Musk and Am'bergris.= _Syn._ HUILE ROYALE. From ambergris, 2 dr.; grain musk, 1/2 dr.; oils of ca.s.sia, lavender, neroli, and nutmeg, of each 10 drops; oil, 1 pint; by infusion. (See _above_.)

=Oil of Sty'rax.= From liquid styrax (pure), 5 dr.; oil of nutmeg, 10 drops; ambergris, 6 gr.; oil, 1 pint; by infusion.

=Oil of Vanil'la.= _Syn._ HUILE a LA VANILLE. From purest olive or almond oil, 1-1/2 pint; vanilla (finest, in powder), 2 oz.; oil of bergamotte, 1 dr.; attar of roses (finest), 15 drops; by infusion.

=OILS (Volatile).=[64] _Syn._ OLEA DESTILLATA, OLEA DISTILLATA, OLEA ESSENTIALIA, OLEA VOLATILIA, L.; HUILES VOLATILES, Fr. The volatile oils are an extensive and important cla.s.s of bodies, derived from the vegetable kingdom, and found in almost every part of the majority of the plants which produce them, except the cotyledons of the seeds, in which, in general, the fixed oils are exclusively stored up. Their presence confers upon flowers, leaves, fruit, seeds, roots, bark, and woods their peculiar and characteristic odours; but among these they are not equally distributed in the same individual, and are often altogether absent from some of them. To them we are indebted for our most delightful perfumes, and our choicest spices and aromatics. Some of them are found to possess valuable medicinal properties, and others are invested with the highest possible interest on account of their peculiar chemical const.i.tution, and the reactions which occur when they are brought into contact with other bodies.

[Footnote 64: Although essential oils are volatile oils, volatile oils are not always essential ones as the term is understood. This is the case with the petroleum and paraffin oils obtained by the distillation of native petroleum and bituminous bodies. To describe the two as synonymous is therefore incorrect.--ED.]

The volatile oils are often called 'essences,' and the same loose and unmeaning term is also commonly applied to their alcoholic solutions.

_Prop._ The volatile or essential oils are usually more limpid and less unctuous than the fixed oils; but some of them are butyraceous or crystalline. Nearly all of them consist of two or more oils, differing in their sp. gr. and boiling points, one of which is generally liquid, the other, in some cases, crystalline. All of them, when perfectly pure, are colourless, though before rectification nearly the whole of them have a pale yellow tint, and some of them are brown, blue, or green. Their odour is that of the plants which yield them, and is usually powerful; their taste is pungent and burning. They mix in all proportions with the fixed oils, dissolve freely in both alcohol and ether, and are sparingly soluble in water, forming 'perfumed' or 'medicated waters.' Their boiling point usually ranges between 310 and 325 Fahr., and is always considerably higher than that of water. They resist saponification, and (excepting oil of cloves) do not combine with the salifiable bases. Their density fluctuates a little on either side of water. The lightest oil is that of citrons (sp. gr. 847), and the heaviest that of sa.s.safras (sp. gr.

1096). When cooled sufficiently, they all solidify. The common temperature of the atmosphere is sufficient for this with some of them, as the oils of roses and aniseed; whilst others require to be cooled below the freezing point of water before they a.s.sume the solid form. In this state they appear to consist of a crystalline or semi-crystalline substance (stearopten, stearessence), and a fluid portion (eleopten, oleiessence). The two may be separated by pressing the concrete oil between the folds of bibulous paper, in the cold. By exposure to the air the volatile oils rapidly absorb oxygen, and become partially converted into resin. This is the cause of the deposit that usually forms in them (especially in the expressed oil of orange) when kept in an ill-corked vessel. The solid crystalline matter which separates from them when kept in closed vessels is stearoptene.

_Cla.s.s._ Chemically considered, the essential oils may be divided into three great cla.s.ses:--

1. Oils composed of carbon and hydrogen only (binary volatile oils, carbo-hydrogens, hydro-carbons, terebenes, camphenes), of which oil of turpentine may be regarded as the type. These are characterised by being, as a cla.s.s, less soluble in rectified spirit and in water than the other essential oils. The oils of bergamot, capivi, cubebs, elemi, hops, juniper, lemons, orange peel, pepper, the gra.s.s oil of India, the laurel oil of Guiana, and some others, belong to this cla.s.s.

2. Oils containing carbon, hydrogen, and oxygen (oxygenated oils), including most of those used in medicine and perfumery. These, as a cla.s.s, are more soluble in rectified spirit and in water than those containing carbon and hydrogen only. To this cla.s.s belong the oils of almonds, aniseed, ca.s.sia, cedar-wood, cinnamon, c.u.min, jasmin, lavender, meadow-sweet (_Spira ulmaria_), orange flowers, pennyroyal, peppermint, spearmint, rosemary, rose-petals, valerian, winter green (_Gaultheria proc.u.mbens_), and others too numerous to mention. A few of these oxygenated oils contain nitrogen.

3. Oils containing sulphur (sulphuretted oils). These are characterised by their extreme pungency, suffocating odour, vesicating power, property of blacking silver, and being decomposed by contact with most other metallic bodies. The oils of a.s.saftida, black mustard seed, garlic, horseradish, and onions, are of this kind. Some sulphuretted oils contain nitrogen.

_Prep._ The volatile oils are generally procured by distilling the odoriferous substances along with water; but in a few instances they are obtained by expression, and still more rarely by the action of alcohol.

According to the common method of proceeding, substances which part freely with their oil are put into the still along with about an equal weight of water, and are at once submitted to distillation. Those substances which give out their oil with difficulty are first soaked for 24 hours, or longer, in about twice their weight of water, to each gallon of which 1 lb. of common salt has been added, in order to raise its boiling point.

The distillation is conducted as quickly as possible, and, when one half the water has come over, it is returned into the still, and this cohobation is repeated, when necessary, until the distilled water ceases to be mixed with oil. The heat of steam or a salt-water bath should be preferably employed. When a naked fire is used, the still should be deep and narrow, by which means the bottom will be better protected by the gradually decreasing quant.i.ty of water towards the end of the process, and empyreuma prevented. When the distilled water is to be repeatedly cohobated on the ingredients, a convenient and economical plan is to so arrange the apparatus that, after the water has separated from the oil in the receiver, it shall flow back again into the still. An ordinary worm-tub, or other like condensing apparatus, may be employed; but in the case of those oils which readily solidify, the temperature of the water in the condenser must not fall below about 55 Fahr.

The mixed vapours which pa.s.s over condense and fall as a milky-looking liquid into the receiver. This separates after a time into two portions, one of which is a solution of a part of the newly eliminated oil in water, and the other is the oil itself. The latter either occupies the upper or the lower portion of the receiver, according as its specific gravity is less or greater than that of distilled water. The separation of the oil and water is effected by allowing the mixed liquids to drop into a 'Florentine receiver' (see _engr._) when the oil is the lighter of the two, by which means the latter acc.u.mulates at _a_, and the water flows over by the spout _b_.

[Ill.u.s.tration]

The same receiver may be employed for oils heavier than water, by reversing the arrangement; but a gla.s.s 'separator' (see _engr._) is, in general, found more convenient. In this case the oil acc.u.mulates at the bottom of the vessel, and may be drawn off by the stop-c.o.c.k provided for the purpose.

[Ill.u.s.tration]

The essential oils of lemons and oranges of commerce, and of some other fruits, are chiefly obtained by submitting the yellow rind to powerful pressure; but in this way they are not so white, nor do they keep so well, as when distilled, although in the case of the fruits referred to the oils are more fragrant than when prepared by any other method.

The London College excluded the usual directions for the preparation of the essential oils from their Pharmacopia of 1851, on the ground that these substances are seldom prepared by the druggist or apothecary, or at all on the small scale.

"The fruit of anise, caraway, and juniper, the flowers of chamomile, lavender, and elder, the berries of allspice, the tops of rosemary, and the entire recent plants of the other herbs, are to be employed." "Put any one of these into an alembic, then pour in as much water as will cover it, and distil the oil into a large vessel, kept cool." (Ph. L. 1836.)

The Edinburgh College directs--"As much water only is to be employed as will prevent empyreuma during the distillation. The distillation may be immediately commenced after a proper maceration, and the oil afterwards separated from the water," in the manner already noticed.

"It is also necessary to observe, in preparing these oils, as well as the distilled waters, that the quality of the substances, their texture, the season of the year, and similar circ.u.mstances, must occasion so many differences, that it is scarcely possible to give any certain and general rules which shall strictly apply to every example. Many things, therefore, must be regulated by the judgment of the operator."

The Dublin College directs the vegetable substances to be macerated in the still with about 5 times their weight of water, for 24 hours, when one half of the water is to be drawn over. The oil having been separated from this in the usual manner, it is to be returned to the still, and the same quant.i.ty drawn over, as before, from which the oil must again be separated.

Chevallier gives the following rules for the distillation of essential oils:--

1. Operate upon as large quant.i.ties as possible, in order to obtain a greater product, and one of finer quality.

2. Conduct the distillation rapidly.

3. Divide the substances minutely, in order to facilitate the extrication of the oil.

4. Employ only sufficient water to prevent the matter operated on from burning, and the product from being contaminated with empyreuma.

5. For substances whose oil is heavier than water, saturate or nearly saturate the water in the still with common salt, to raise the boiling point, and thus to enable the vapour to carry over more oil.

6. Employ, when possible, water which has been already distilled from off the same substances, and has thus become saturated with oil.

7. For oils naturally fluid, keep the water in the refrigerator cool; but for those oils which easily become solid, preserve it at 80 to 90 Fahr.(?)

To the above may be added--

8. Collect the oil as soon as possible after it separates from the water with which it pa.s.ses over, and in its subsequent treatment keep it, as much as possible, from free contact with the air.

Dr Ure remarks, "The narrower and taller the alembic is, within certain limits, the greater will be the proportion of oil, relative to that of the aromatic water, from like proportions of aqueous and vegetable matter employed." "Some place the plants in baskets, and suspend these immediately over the bottom of the still, under the water, or above its surface in the steam; but the best mode, in my opinion, is to stuff an upright cylinder full of the plants and drive down through them steam of any desired force, its tension and its temperature being further regulated by the size of the outlet-orifice leading to the condenser. The cylinder should be made of strong copper, tinned inside, and encased in the worst conducting species of wood, such as soft deal or sycamore."

The newly distilled oils may be separated from adhering water, which frequently renders them partially opaque or 'cloudy,' by repose in a temperature between 60 and 70 Fahr., and subsequent decantation; but to render them quite dry (anhydrous), it is necessary to let them stand over some fragments of fused chloride of calcium. This is not, however, required with the commercial oils.

The rectification of the volatile oils is commonly performed without water, by the careful application of a heat just sufficient to make them flow over pretty rapidly, so that they may be kept heated for as short a time as possible. One half, or at most two thirds only, is drawn off, that left in the retort being usually mixed with raw oil intended to be sold in that state. This method often leads to much loss and disappointment, and we have known more than one rather dangerous explosion result from its use. A better plan is to rectify the oil from strong brine, and then to separate any adhering water, either by repose or chloride of calcium.