Glycerin.
This substance, which may be called a true cosmetic in itself, as it possesses marked solvent power for cutaneous coloring matters and at the same time imparts to the skin delicacy and flexibility, is at present to be had commercially in great purity. Pure glycerin is a brilliant, colorless, and odorless substance of the consistence of a thick syrup, which mixes with water and alcohol in all proportions and has a slightly warm but very sweet taste. It readily absorbs aromatic substances and is used in many valued toilet articles in combination with fats and perfumes. Recently we have succeeded in using glycerin most successfully for the extraction of aromatic substances.
Oil of Mirbane,
also called artificial oil of bitter almonds, nitrobenzol, and essence of mirbane. This substance, which is now largely used in perfumery and soap manufacture, is obtained by the action of fuming nitric acid on benzol. The mixture becomes hot and emits masses of brown vapors, and there is formed a yellow oily body which is washed with water and soda solution until the washings escape colorless. Pure nitrobenzol is not soluble in water, but in alcohol or ether, boils at 213° C. (415° F.), and congeals at-5 to 6° C. (21-23° F.). Its spec. grav. is 1·2 or a little over. Any oil of mirbane having a lower specific gravity than 1·2 at 15° C. (59° F.) is spurious, most likely nitrotoluol. Its odor greatly resembles that of oil of bitter almonds, but can be clearly differentiated from it on comparison. Care must be taken in inhaling the vapor when undiluted, as it is poisonous. By distillation nitrobenzol can be obtained quite colorless, and in this form is often used for the adulteration of genuine oil of bitter almonds. This adulteration, however, can be easily demonstrated by heating for a short time with an alcoholic solution of a caustic alkali which separates from nitrobenzol a brown resinous substance, while true oil of bitter almonds loses its odor and changes into benzoic acid which unites with the alkali.
Paraffin.
This substance is one of the products of the distillation of petroleum, coal, peat, and other carbonaceous sources. It is a crystalline, brittle body, closely resembling wax in appearance and melting between 51 and 60° C. (124 and 140° F.). Paraffin, which is now made on a large scale for the manufacture of candles, is very useful in perfumery as a partial substitute for the much more expensive wax or spermaceti, over which it has the advantage, besides its cheapness, that it imparts to the articles great transparency—a quality which is valued highly in fine perfumeries. The addition of some paraffin to pomades renders them more consistent and counteracts their tendency to become rancid. Distilled paraffin always has a crystalline form, differing from the paraffin-like residues left after the distillation of petroleum (so-called vaselins, etc., see below) which are always amorphous.
Pyrogallic Acid
appears in commerce as a white crystalline powder, made by heating gallic acid to 200-210° C. (392-410° F.). With iron salts, pyrogallic acid forms bluish-black combinations and precipitates the metal from silver solutions as a velvety-black powder. On account of these properties pyrogallic acid is used in perfumery as a constituent of some hair dyes.
Sulphide of Potassium,
liver of sulphur, hepar sulphuris, potassii sulphuretum, the pentasulphide of potassium, is obtained by fusing together potash and sulphur, in the shape of a leather-brown mass which is soluble in water and on exposure to the air is gradually decomposed with the development of the offensive sulphuretted hydrogen gas; hence it should be preserved in well-closed vessels. An aqueous solution of this substance forms with lead or silver salts a black precipitate of sulphide of lead or silver, and is used for some hair dyes.
Starch Flour
(amylum) is prepared from various vegetables such as potatoes, rice, arrowroot, sago, etc., and when pure appears as an insoluble white powder which the microscope shows to be grains consisting of many superimposed layers. In commerce the price of the different varieties of starch fluctuates greatly; in perfumery well-cleansed potato starch can very well be used for dusting powders, and the so-called poudre de riz; in this country, corn starch is preferable.
Vanillin,
that is, the body to which vanilla owes its fragrance, is now made artificially and can be used in place of vanilla for soaps and pomades.
Vaselin.
In the distillation of petroleum there remain in the still as a residue large quantities of a substance which when purified is colorless and, according to the nature of the petroleum, at ordinary temperatures has either the consistence of lard, melting under the heat of the hand, or forms an oily liquid. In perfumery vaselin can be used like fat or oil, over which it has the advantage in that it always remains odorless and free from acid; hence it is very appropriate for the manufacture of pomades. The market affords numerous varieties of this substance, under different names: vaselin (oil and solid), albolene (oil and solid), cosmolin, etc., etc.
Spermaceti
is a substance found in the skull cavities of several whales and dolphins. In its properties it stands midway between beeswax, paraffin, and firm fats. In the living animal spermaceti is fluid, but after its death it congeals to a white crystalline mass of a fatty lustre, which melts at 40° C. (104° F.), and is frequently used for fine candles as well as for other articles.
Wax
(Cera alba), the well-known product of the bee; in perfumery only bleached (white) wax is employed. In recent years Japanese wax has appeared in commerce; this is of vegetable origin, but in its properties resembles beeswax.
Subnitrate of Bismuth,
bismuth white, pearl white, bismuthi subnitras, blanc de bismuth, blanc de perles, the basic nitrate of bismuth, the chief ingredient of many skin cosmetics, is prepared by dissolving metallic bismuth in moderately strong nitric acid, and pouring the solution into a large quantity of water, whereupon the subnitrate is precipitated.
The precipitated powder is collected on a funnel and washed with pure water until the wash water no longer changes blue tincture of litmus to red. The bismuth white is dried and preserved in well-closed vessels, since in the air it gradually assumes a yellowish color; for any sulphuretted hydrogen present in the air is greedily absorbed by this salt, and the resulting combination with sulphur has a black color.
Oxide of Tin
is obtained by treating metallic tin with fuming nitric acid, adding the solution to a large quantity of water, and washing the product, which forms a white insoluble powder used cosmetically for polishing the finger nails.
Besides the chemical products here enumerated, some others find application in perfumery; we shall describe their properties in connection with the articles into which they enter. In this connection mention may be made of the fact that more and more aromatic substances are now made artificially which were formerly obtained with difficulty from plants. Besides vanillin mentioned above, cumarin, oil of wintergreen, and some other products are prepared artificially. Heliotropin and nerolin are artificially prepared substances, possessing an odor resembling that of heliotrope and oil of neroli, respectively, but not identical chemically with the natural odorous substance. Artificial musk (Baur’s), is playing a rôle at present, but is not identical with the natural substance.