VI T or vitriolic acid ; and which is ei- ther white, bkie, or green, accord- ing to the metal employed. IVidte Vitriol, or Vitriol of Zinc, is found in the mines of Gosjar, in Saxony, in a native state, and con- sists of white transparent pieces ; but, the quantity thus obtained be- ing insufficient for the demand, this salt is generally prepared by inixing 5 parts of sulphuric acid with 20 of distilled water, and gradually adding 3 parts of zinc : when the ebullition ceases, the li- quor is strained 3 and, after being evaporated, it is deposited in a cool place, where it shoots into white crystals. It is sometimes employed by painters, for the purpose of speedily drying oil-colours : its taste is nauseous, though sweetish ; be- ing frequently given as an emetic, in doses of from.5 or 6 grains to half a dram ; the operation of which is very powerful ; and such drug ought therefore to be regularly prescribed. But its chief utility is that of an astringent and desicca- tive, in extenial applications : thus, when dissolved in the proportion of 16 grains in 8 oz. of water, with the addition of 16 drops of weak vitriolic acid, it forms an useful collyrium, or eye-water. A solu- tion of 2 drams of white vitriol, and a similar quantity of alum, in a pint of water, is likewise em- ployed for cleansing foul ulcers, and repelling cutaneous erliptions. Green Fitrioi consists of sulphu- ric acid diluted with 10 or 12 times its weight of water, in which iron- filings are dissolved : when the ef- fervescence ceases, the mixture is for some time placed in a sand- batlj 5 next, the liquor is strained through paper; and, after being evaporated^ it shoots into rhomboi- dal crystals, which are also termed VIT [^75 Salt of Steel. — Green vitriol is given in doses of from half a grain to 5 grains ; according to the age, strength, or case of the patient j being one of the safest forms ia which iron can be administered.— See vol. iii. p. 31. Blue Vitriol, is chiefly imported from Italy, paying a duty of l^d,. per lb. It is made by stratifying plates of copper with sulphur ; and, on slow combustion, the sulphuric* acid corrodes the copper : the me- tal is then boiled in water, till the saline particles are dissolved 3 when^ after repeated solution, and sub- sequent evaporation, the whole is reduced to the crystallizing point. — Vitriol of copper is chiefly em- ployed externally as a. caustic, to remove the flesh of fungous ul- cers ; for which purpose it is very useful : on account of its virulent properties, however, it ought never to be administered internally, with- out medical advice. Vitriolic Acid, Sulphuric Acid, or Oil of Vitriol, an tise- ful liquid, prepared by the combus- tion of sulphur in close vessels, with the addition of 1 -8th or l-12tli part of nitre, and a little water, to condense the vapour : after which it is concentrated and purified by- evaporation. Beside the purposes to which it may be applied (and which are stated in the articles Bleaching and Sulphur), this acid, when properly diluted, has successfully been administered in hemorrhages, fevers of the typhus kind, and the -itch ; in doses of from 40 to 60 drops in water : but^ when combined in the proijortion of one part, whh eight of lard, or other unduous matter, it forms aa efficacious application to the parts affefted, in chronic cutaneous erup- tions, and likewise as a rube fa- T 2 cient
