Lilac oil is obtained from the flowers of Syringa vulgaris, the lilac, by aqueous distillation and subsequent extraction with benzine. It is also frequently prepared by the absorption process. It is used for the most expensive perfumes, and is seldom found in commerce.
Limes, oil of (oleum limettæ), is derived from the rind of the fruit of Citrus limetta, or lime. The oil is obtained in the same manner as oil of lemons, which it somewhat resembles. Its mean specific gravity is 0.8734 at 84° F. The oil made by the écuelle process is of a decidedly yellow color, varying in intensity, being darker in the fresh product. The difference in flavor and aroma is so marked as scarcely to require any other means of distinguishing the oil made by the écuelle process from that obtained by distillation, the first having a decided fragrant lemon smell, whilst the distilled oil is very inferior, frequently possessing little more than the smell of turpentine. Large quantities of oil of limes are manufactured in Dominica, but most of the oil exported from there is of an inferior quality and was formerly solely used for adulterating oil of lemons. Lately it has also been employed for scenting soaps and in the manufacture of the common essences and perfumes.
Licari oil, linaloë oil, is obtained, partially in Mexico and partially in Cayenne, from the wood of the white cedar (bois de rose femelle), Licari canali. It is limpid, has an agreeable odor, reminding one of roses, and does not become solid at 4° F. Its specific gravity is 0.868 at 59° F., and it boils at 388.4° F.
Marjoram oils.—By distilling the leaves of Origanum marjorana, L., the marjoram oil (oleum marjoranæ) is obtained. It is yellowish or green-yellowish, but becomes reddish-brown by age. If badly kept it finally becomes thickly-fluid and sticky, sometimes depositing a reddish stearoptene. The odor of marjoram oil is less agreeable than that of the plant, and the taste peculiar, bitter, cooling. The oil dissolves readily in 90 per cent. alcohol, and when mixed with equal parts of it yields a clear solution. Its specific gravity is 0.89 to 0.91. It should be kept in entirely filled, well-closed bottles in a shady place. On coming in contact with air, it absorbs oxygen with avidity and forms a white, odorless, crystalline mass.
From Origanum vulgare, L., the ordinary marjoram oil (oleum origani vulgaris) is obtained. It is yellowish or reddish, limpid, of specific gravity 0.90 to 0.95, and has a camphor-like odor.
Spanish marjoram (oleum origani cretici) is obtained by distillation from the flowering plants of several varieties of marjoram (Or. creticum, Or. hirtum, Or. smyrnæum). It is brought into commerce from Trieste, Smyrna, Salonica, and other Mediterranean seaports. The oil exported from France appears to be derived from another variety of marjoram; at least it shows a different behavior and approaches more the ordinary marjoram oil. The genuine oil is thickly-fluid, generally yellow-brown; of specific gravity O.95 to O.97; has a strong, aromatic odor, and produces upon the tongue a sharp continued burning. It dissolves in equal parts of 90 per cent. alcohol. It is chiefly adulterated with copaiba oil, the presence of which can be recognized by the oil dissolving with greater difficulty.
The marjoram oils are but little used for perfuming purposes.
Mignonette oil (oleum résédæ). The well-known mignonette, Réséda odoratissima, yields a thick yellowish oil, either by maceration and absorption, or by extraction with ether or petroleum-ether. It has a penetrating, disagreeable odor, which can only be rendered agreeable by greatly diluting the oil. In gathering the flowers care must be had not to mix them with leaves, as this spoils the odor of the oil.
Myrrh oil (oleum myrthæ) is obtained from the leaves of Myrtus communis, L. It is yellowish, dextrorotatory, of specific gravity 0.910 at 60.8° F., and commences to boil at 320° F. As its principal constituents, Jahns has established a terpene (C10H16), boiling at from 316.4° to 320° F., and turning the plane of polarization to the right, and cineol (C10H16O), which boils at 348.8° F. Besides these principal constituents there seems to be present a very small quantity of a camphor, corresponding very likely to the formula C10H16O. Myrtol, which was formerly supposed to exist in myrtle oil, has been found to be a mixture of the dextrorotatory terpene and of cineol.
Nutmeg oils.—From mace, the fresh aril of the nutmeg (Myristica fragrans, Houtt, natural order Myristicaceæ), mace oil (oleum macidis), is obtained by distillation. It is straw-yellow or yellowish, later on yellow-reddish, clear, somewhat thickly-fluid, of a strong odor resembling that of mace, and a taste at first mild, but later on pungent and aromatic. It mixes clear in every proportion with absolute alcohol, but of 90 per cent. alcohol, 5 to 6 volumes are required for a clear solution. The specific gravity of the oil varies from 0.87 to 0.92. With iodine it detonates, vapors being emitted. The oil obtained from dried mace has a less agreeable odor.