Or, to test for adulteration with fixed oils, place a drop of the sus pected oil on paper and evaporate it with gentle heat. The presence of a fixed oil will be detected by a perma nent greasy stain.
Or distill off the volatile oil with gentle heat. The fixed oil will be left behind.
Or add three or four times its vol ume of 80 per cent alcohol. The fixed oil will not be dissolved.
Or, to test for alcohol, dilute the suspected oil with water. If the quantity of alcohol is large, the mix ture will become roily or turbid.
To test for oil of turpentine— which is often used to adulterate the oils of orange, lemon, neroli, and the like—set a little of the oil on fire, blow it out, and the presence of tur pentine may be detected by its char acteristic odor.
Odor of Perfumes.—The odor of the volatile oils is probably caused by their gradual oxidation or chemi cal union with the oxygen of the air. This is the same process as that which takes place in the rusting of iron, and is similarly promoted by moisture. When treated chemically so' as to be perfectly pure and free from oxygen and moisture, the most powerful perfumes are odorless. Ex posure to moist air restores their odor. Perfume-bearing flowers are much more fragrant when mois tened, as with dew. Roses and other fragrant blossoms are nearly scent less in dry climates. Rose jars and other mixtures of dry perfume-bear ing substances give off very much more perfume when slightly mois tened.
Individual Perfumes.—Many per sons prefer to have a perfume of their own different from those which are on the market or used by others among their acquaintances. This is not especially difficult, although the perfumes that are usually employed, such as heliotrope, violet, white rose, and the like, may, of course, be ob tained by anyone. An individual perfume may be secured by experi menting with two or more essential oils, mixing and blending a few drops at a time until a new and agreeable fragrance is obtained. This is, in fact, the way in which colognes and similar preparations are compounded for the market. One celebrated " German cologne " of the past gen eration is said to have contained no fewer than thirty different kinds of ingredients, the result being a pun gent perfume of a peculiarly agree able odor. The proportion in which
the various ingredients should be blended is entirely a matter of indi vidual preference, to be determined by experiment.
Sachet Powders. — Various solid perfume-bearing substances, to which may be added small quantities of the essential oils, are used in powdered form and sprinkled between layers of absorbent cotton or otherwise to per fume garments laid away in chests or drawers. To prepare the various sachet powders, it is only necessary to finely pulverize the solids in a mor tar, add the essential oils drop by drop, and mix the whole thoroughly together. When not required for use, sachet powder should be kept in tightly sealed boxes, jars, or bottles, so that the volatile perfumes will not be lost by evaporation.
Incense — Pastilles. — Several per fume-bearing substances may be util ized in solid form by mixing them with combustibles, such as charcoal, niter, and various gums, and setting them on fire to perfume apartments. The table on page 478 embraces a number of recipes for incense pas tilles. In all cases first reduce the solids separately to powder in a mor tar. This may be done by beating the ingredients together in an earthen ware bowl, or by mixing them on a marble slab or plate of glass with an ordinary knife or a palette knife hav ing a thin, broad blade. If gum tragacanth is used, it should be dis solved in water to the consistency of mucilage. The essential oils and other liquid perfumes are then to be added and thoroughly worked into the mass, the whole formed into small cones like chocolate drops, and thoroughly dried either in a very slow oven or by the heat of the sun. When re quired for use, one or more of these cones may be placed on any bot sur face or set on fire at the tip and al lowed to gradually smolder, when they will give off an agreeable per fume.
Or, where niter and charcoal are both employed, dissolve the niter in sufficient soft water to make a soft paste with the charcoal. Dry this paste thoroughly, and pour over it the liquid perfumes. If other solid ingredients are added, they should be in powdered form. Mix the whole with gum tragacanth dissolved as above. Dry and use as above.