A practical treatise on the manufacture of perfumery

by C. Deite

Green camomile oil from the genuine or Roman camomile possesses an agreeable odor of fresh lemons; it is more seldom used than the other.

On account of the slight yield obtained from the flowers, camomile oil is rather expensive.

Caraway oil (oleum carui) is obtained by distillation from the seeds of the well-known aromatic plant Carum carui, or the caraway, natural order Umbelliferæ. In a fresh, purified state the oil is colorless, very thinly-fluid and possesses a pungent taste. The oil prepared from cleansed Dutch seed is best liked, while that distilled from Norwegian or Tyrolese seed is not much in demand, its taste and odor not being so pure on account of the many impurities mixed with these kinds of seed.

Caraway oil consists mainly of a terpene, C₁₀H₁₆, called carvene, specific gravity 0.870, and of carvol, specific gravity 0.960. The richer the oil in carvol, the higher its specific gravity. Good caraway oil should have a specific gravity of 0.900 to 0.910. The carvol being the actual bearer of the aroma, the value of the oil exclusively depends on the content of it. In the better varieties of oil, the content of carvol amounts to from 45 to 50 per cent., while poorer qualities generally contain only from 40 to 42 per cent. The carvol and carvene are now frequently separated by fractional distillation. The carvol, which has three times as strong an odor and taste as the carvene, dissolves with much greater facility in alcohol. The carvene being offered at very low prices might be suitable for perfuming cheap soaps.

Caraway oil obtained by distillation from the plant has a less agreeable odor than that from the seed, and possesses an acrid resinous taste.

The purity of caraway oil is recognized by its dissolving clear in equal parts of 90 per cent. alcohol. If such is not the case, the oil contains either an admixture of oil of turpentine or does not possess the full normal content of carvol. Pure caraway oil does not detonate with iodine, which is the case with oil containing oil of turpentine.

Caraway oil is chiefly used for perfuming soap; for handkerchief perfumes it is not suitable.

Cedar oil (oleum cedri) is obtained by distillation from the shavings of the wood of the American or Virginia cedar (Juniperus virginiana). For the distillation of oil the waste falling off in the manufacture of lead-pencils is almost exclusively used. It yields about 2 to 3 per cent. of oil. The oil is thinly-fluid, of specific gravity 0.9622, of a greenish color, and an agreeable but not very penetrating odor. It is a mixture of a terpene, boiling at about 540° F., and of a hydrocarbon. The latter, which is called cidrin, forms the fluid portion of the oil. It has a specific gravity of 0.984, and boils at about 459° F.

Cedar oil is extensively used in the manufacture of toilet soap, it serving as the basis for other perfumes. Care must, however, be taken that its odor does not preponderate, as in such case it readily produces an unpleasant effect. The oil being cheap, adulteration is scarcely to be feared.