East Indian geranium oil is obtained, chiefly in the Presidency of Bombay, from Andropogon Schoenantus, L. It is greenish-yellow to yellow-brown, has a specific gravity of 0.906 at 59° F., and consists mainly of geraniol (C10H18O). Its odor is rose-like, though modified by a lemon-like odor. It is principally used for perfuming cheaper articles.
French and African geranium oils (oleum geranii) are obtained by distillation with water from the leaves of various species of pelargonium. Many different kinds of this oil are found in commerce. The finest and most expensive are the Spanish and French geranium oils, so-called rosé, which are distinguished by their fine odor, closely resembling that of rose oil. They are derived from Pelargonium radula, and are either yellowish, brownish, or pale green, the brownish oils being preferred. It congeals at 60.8° F. and turns the plane of polarization to the right. Another good geranium oil is the African, which is chiefly prepared in Algiers from Pelargonium roseum, Wildenow, and P. odoratissimum, Aiton. It closely resembles the French oil, but turns the plane of polarization to the left.
French geranium oil is said to be frequently adulterated with fat or copaiba oil; but geranium oil being soluble in 70 per cent. alcohol, such adulterations are readily detected. Add to 5 cubic centimeters of 70 per cent. alcohol (specific gravity 0.890) at 59° to 62.5° F., 10 drops of the oil, and shake. If a clear solution results the oil is very likely unadulterated.
The so-called Turkish geranium oil is frequently found mixed with cocoanut oil. To detect this, place the oil in a test-tube in ice or a cold mixture for several hours, whereby the cocoanut oil separates as a white substance. Adulterations of upward to 20 per cent. are said to frequently occur.
Reliable tests to detect an adulteration of the better qualities of geranium oil with those of a lower grade do not exist, the odor being the only guide.
Jasmine oil or oil of jessamine, from the flowers of Jasminium officinale, L., and J. grandiflorum.—The oil is exclusively obtained by the absorption process, and is the most prized by the perfumer. It is, however, exceedingly rare on account of the enormous cost of its production. The extract of jasmine, the "essence de jasmine" of the French manufactories, is a solution of the oil, as obtained by extraction with lard or beef suet, in strong spirit of wine. The odor of jasmine oil is so peculiar that it is without comparison, and as such cannot be imitated.
Juniper oil (oleum juniperi) is obtained by distillation from the fruits of Juniperus communis, L., or juniper. The berries used for the purpose should be fully grown and fresh and bruised before being placed in the still. Unripe berries yield a smaller quantity and an oil of somewhat different properties than ripe berries. The oil obtained by distillation with steam is colorless and that by ordinary distillation yellowish, the former having a specific gravity of 0.840 to 0.860 and the latter of 0.850 to 0.900. It consists mainly of terpenes. By standing, a stearoptene is separated, which crystallizes in feathery needles from hot spirit of wine. The odor and taste of juniper oil remind one at the same time of juniper berries and oil of turpentine.
Juniper oil has a great tendency to thicken; it becomes resinous, acid and thickly fluid, formic acid being formed. It should be kept in well-closed bottles, and protected from light. It is frequently adulterated with oil of turpentine and juniper-wood oil. It may be tested by its behavior towards alcohol, as well as by the taste. A drop of the oil rubbed up with sugar, and shaken with 500 grammes of water, should not impart an acrid taste to the water. Juniper oil gives a clear solution with ½ part absolute alcohol; by a larger quantity it is rendered turbid.
Lavender oil (oleum lavandulæ.)—Large quantities of this oil are distilled in Southern France, in the neighborhood of Grasse and Nimes, from the flowers of lavandula officinalis, Chaix, which grows wild in that region. It is limpid, colorless, or yellowish, has a strong odor and a pungent, aromatic, somewhat bitter taste. With 90 per cent. alcohol it mixes clear in every proportion, boils at 320° F., and has a specific gravity of 0.876 to 0.905. It turns the plane of polarization to the left.