Called also viride aeris, cupri ru-higo, calcithos, Hispanicum viride, verdigrise. It is copper, corroded by a fermented vegetable acid into a bluish green substance. The copper is made into very thin plates, which are suspended over the vapours arising from wine, during its acetous fermentation: or the busks and stalks of grapes are dried, and, when bruised, are dipped in wine and made into balls. When they have acquired the acetous acid they are broken with the hand, and stratified with these copper plates, and left until the verdigrise is produced. The best, as well as the greatest quantity, is made at Montpellier, where there is one sort in powder and another in lumps. The whole process, as now practised in Montpellier, may be seen in the Cyclopedia under Verdigrease. The sort which we receive from France is generally mixed with the stalks of grapes, which may be separated by pulverisation, as they are more difficultly powdered than the verdigrise itself. It is purified by dissolving in six or seven times its weight of distilled vinegar, decanting and evaporating the solution. If good, it is dry, of a beautiful deep green, with a few white spots; and when rubbed on the hand with a little saliva or water it forms a smooth paste, free from grittiness. It is adulterated by mixing pumice stone, marble, vitriol, etc. The first two are discovered by rubbing the suspected verdigrise betwixt the thumb and the finger, previously wetted, by which the pumice stone and marble become white: the latter is discovered by burning a little on a tile, by which the vitriol is turned into a red substance. In spirit of wine, and in water, this concrete is partially soluble: in vinegar it is wholly so. If a saturated solution of it in vinegar is set to exhale in a warm place, the greatest part of the verdigrise may be recovered in a crystalline form; and if these crystals are distilled in a retort, the acetous acid ascends from them in a highly concentrated state, forming the acetic acid, and the crystals are then called distilled or calcined verdigrise, or the vitriol of Venus: if set in a damp place to dissolve, it is called the liquor of Venus. Verdigrise is used by dyers, skinners, hatters, painters, etc. as well as in medicine: in miniature painting the distilled sort is the best. Its use, as an external medicine, is to deterge foul ulcers, as in the ung. basil, viride and the mel aeruginis. If it is made into a paste with saliva, or any thing not oily or unctuous, it will dissolve hard calli. In phagedenic ulcers, and the most unpromising sores, with ichor, fungus, etc. copper is useful. Foul chancres, that yield not to mercury inwardly, have been removed by a solution of the cuprum vitriolatum. Internally taken, a vomiting is instantly provoked by a grain or two of verdigrise, or vitriol of copper, so for its speedy effect it may be used to discharge any poisonous matter received into the stomach. Large portions, as four drams or more, have been swallowed without any other inconvenience than the present vomiting; yet, in smaller quantities, besides the vomiting, it excites a pain in the stomach and griping in the bowels, tenesmus, ulcerations, bloody stools, difficult breathing, and contractions of the limbs, which often terminate in death. Hence great care should be taken of copper or brass vessels, in which acids or fats are boiled, lest the verdigrise should be productive of disease. Though acids, etc. while boiling, do not corrode the metal, this is soon effected when the boiling heat is abated. In case of verdigrise being swallowed, oil and warm water, or large quantities of milk and water, both by the mouth and by the anus, in order to wash away the whole of this offensive matter, must be given; a discharge by vomiting with all possible speed must be excited; and, after due evacuations, an anodyne may be given: if there is great pain, cordials, with a milk diet, will be useful. Pills made of aerugo, we are informed by Gmelin, have been given as a remedy in cancers.

Verdigrise cannot be reduced to powder but by levi-gation.