The adulterations by means of other essential oils are much more difficult of discovery, and much more general ; in fact, it is said that none of the Bulgarian otto is completely free from this kind of sophistication. The oils employed for the purpose are certain of the grass oils (Andropogon and Cymbopogon spp.), notably that afforded by Andropogon Schcenanthus (see Ginger-grass-oil, p. 1422), called idris-yaghi by the Turks, and commonly known to Europeans as " geranium-oil," though quite distinct from true geranium-oil. The addition is generally made by sprinkling it upon the rose leaves before distilling. It is largely produced in the neighbourhood of Delhi, and exported to Turkey by way of Arabia ; it is sold by Arabs in Constantinople in large, bladder-shaped, tinned copper vessels, holding about 120 lb. As it is usually itself adulterated with some fatty oil, it needs to undergo purification before use. This is effected in the following manner :—The crude oil is repeatedly shaken up with water acidulated with lemon-juice, from which it is poured off after standing for a day. The washed oil is placed in shallow saucers, well exposed to sun and air, by which it gradually loses its objectionable odour. Spring and early summer are the best seasons for the operation, which occupies 2-4 weeks, according to the state of the weather, and the quality of the oil. The general characters of this oil are so similar to those of otto of roses—even the odour bearing a distant resemblance,—that their discrimination when mixed is a matter of practical impossibility. The ratio of the adulteration varies from a small figure up to 80-90 per cent. The only safeguard against deception is to pay a fair price, and to deal with firma of good repute.
The otto is put up in squat-shaped flasks of tinned copper, called kunkumas, holding 1-10 lb., and sewn up in white woollen cloths. Usually their contents are transferred at Constantinople into small gilded bottles of German manufacture, for export. The Bulgarian otto-harvest, during the five years 1867-71, was reckoned to average somewhat below 400,000 meticals, miskals, or midkals (of about 3 dwt. troy), or 4226 lb. ay. ; that of 1873, which was good, was estimated at 500,000, value about 700,000/. The harvest of 1880 realized more than 1,000,0001., though the roses them selves were not so valuable as in 1876. About 300,000 2neticals of otto, valued at 932,077/., were exported in 1876 from Philippopolis, chiefly to France, Australia, America, and Germany.
Rosemary-oils.—The common rosemary (Rosmarinus officinalis) is a native of S. Europe and Asia Minor, growing abundantly wild in Spain, France, Germany, and Austro-Hungary, and under cultivation to a small extent at Mitcham, in Surrey. The cultivation resembles that of lavender, except that the plant requires longer to mature. The otto produced in England is valued at 10 times the price of Continental articles, but its quantity is so inconsiderable that it scarcely forms a commercial article. The market is chiefly supplied from plants growing wild in S. France, and
Italy, as well as on the islands of Lesina, Maslinica, and Lissa, off the Dalmatian coast, where the peasants annually retort some 20,000 funti (of 1.2 lb.), and export 300-350 quintals of the oil via Trieste. In France and Italy, the plant is gathered in summer, but not while in flower ; generally the entire herb is distilled, but sometimes the flowering tops only are selected for the operation. In Dalmatia, the biennial shoots are cut in May, sun-dried for about 8 days, and deprived of their leaves. The latter are then moistened with water, and treated in copper stills over naked fires. The yield from 1 cwt. of fresh herb is about 24 oz. of oil, but is subject to great variation. The oil is colourless or yellowish, with a somewhat camphor-like odour and flavour of the herb ; sp. gr. 0.886-0.933 ; dissolves readily in alcohol. It has a very wide use in perfumery. Trieste supplies 34,000-40,000 lb. annually of the oil to Europe and America.
The so-called " wild rosemary " or " Labrador tea," Ledum palustre (see Narcotics—Lee/urn, p. 1308), gives an essential oil by aqueous distillation.
Rosewood- or Rhodium-oil.—By aqueous distillation, the root and stem of Convolvulus scoparius and C. floridus, growing in the Canaries, afford an essential oil, in the proportion of about 3 oz. from 1 cwt. The oil is thin, pale-yellow, with an odour of roses and cuhebs, and a bitter aromatic flavour. It has disappeared from commerce, and is completely replaced in perfumery by an artificial compound.
Rue-oil.—The whole herb of Beta graveolens, submitted to aqueous distillation, affords a colourless oil (about 1 lb. from 150-200 lb.), with strong odour and flavour of the herb, sp. gr, congealing at —1°- —2° (301°-24° F.), and boiling at 228°-230° (442F-446° F.). It is principally employed in aromatic vinegars (see p. 335).
Saffron-oil.—The stigmata of Crocus satires (see Dyestuffa—Saffron, p. 866), by aqueous distillation, yield a thin yellow oil, with an odour of saffron, which is slowly converted into a solid mass that sinks in water.
Sagapenum-oil.—By distilling sagapenum (see Resinous Subatances—Sagapenum) with water, it affords a thin, yellow oil, with a garlic-like odour at first, then becoming turpentinous, drying to a translucid varnish, and dissolving readily in alcohol.
Sage-oil.—The whole herb of sage ( Salvia officinalis), by aqueous distillation, yields a greenish-yellow oil, with the odour and flavour of the herb, sp. gr. 0.864, boiling at 130°-160° (266°-320° F.) It is rarely employed, but is a useful perfume. The plant grows both wild and cultivated around Grasse (S. France), and yields 1 lb. of oil from 300 lb.