AROMATIC VINEGAR. (FR., Tinaigre de toilette ; GEL, Aromatische Essig.) Acetum aromaticum.—This is the name given to various mixtures of aromatic substances with strong, pore acetic acid. They are prepared chiefly in France, and in the following manner : A quantity, about 20 lb., of crystals of acetate of copper, or verdigris, is broken up small, and placed in an earthenware retort of about 2 gallons capacity. The mouth of this retort is connected with a series of stoppered globes, each of which is constantly kept cool by a stream of water ; the last of these receivers is furnished with a safety tube, the end of which dips into a vessel filled with water. The whole apparatus is carefully tested, and the retort is placed in a reverberatory furnace and heated gently. The acetate of copper is decomposed by the action of the heat into acetic acid, which passes over as a vapour, and is condensed in the receivers, and into metallic copper, which remains in the retort mixed with a little charcoal. When the vapours of acetic acid cease to be given off, the retort is withdrawn from the furnace, and allowed to cool. The 20 lb. of crystals should yield about 10 lb. of crude acetic acid, of specific gravity 1.061; this acid is of a greenish colour, owing to the presence of certain salts of copper, which are formed and carried over during the operation. It is purified by further distillation in a glass retort, heated by a sand-bath, and fitted with a tubulated glass receiver. The moisture contained in the salt renders the first portion
of the distillate too weak ; it is therefore rejected until the liquid in the receiver has a specific gravity of about when the distillate is collected. It then constitutes the purest and strongest acetic acid known. In this acid are dissolved various essential oils, such as oil of cloves, rosemary, thyme, lavender, mint, and rue. Camphor is also frequently added. The following recipe has been given by the Edinburgh Pharmacopoeia : One pint and a half of acetic acid ; one ounce each of dried rosemary and thyme ; one half-ounce of lavender ; one half-drachm of bruised cloves. This mixture is to be macerated for a week, strained, strongly expressed, and filtered.
The " Vinaigre des quatre voleurs" contains the following substances : Camphor dissolved in alcohol ; the dried ends of the wormwood plant, rosemary, sage, mint, rue, garlic, dried lavender flowers, the root of the Acorus calantus, cinnamon, mild nutmeg. It owes its name, it is said, to the fact that four thieves preserved themselves by its use from contagion while plundering the victims of the plague of Marseilles.
Aromatic vinegars are antiseptic and disinfectant ; they are largely employed as articles of toilet.