VITRIOL. 



an eighth to a fourtli of a drachm of the pure acid twice or 

 thrice a day. It is faid to fucceed equally in the dry and 

 moil! itch ; and when given to nurfcs, to cure both them- 

 felves and their children. 



When oil of vitriol, and reftified fpirit of wine, are long 

 digefted together, or diltilled, a part of the acid unites with 

 the vinous I'pirit into a new compound, very volatile and in- 

 flammable, of no perceptible acidity, of a ftrong and very 

 fragrant fmell, and an aromatic kind of talle : this dulcified 

 part, more volatile than the reft, feparatcs and rifes firft in 

 diilillation, and may thus be collefted by itfelf. The Col- 

 lege of London direfted thh Jpiritus vltrioli dulcis to be made 

 by cautioudy and gradually mixing a pound of oil of vitriol, 

 and a pint of reftified fpirit of wine, and fetting them to 

 dillil with a very gentle heat : that of Edinburgh ordered 

 the fame quantity of the oil of vitriol to be dropt into four 

 times as much of the vinous fpirit, and the mixture to be 

 digefted in a clofe veflel, for eight days, previoufly to the 

 diftillation, with a view of promoting the coalition of the 

 two ingredients. The different proportions of the acid 

 fpirit to the vinous, in thefe prefcriptions, make no material 

 variation in the qualities of the produft, provided the diilil- 

 lation be duly conduced ; for the fmalleft of the above pro- 

 portions of acid is much more than the vinous fpirit can dul- 

 cify, and all the redundant acid remains in either cafe behind. 

 The true dulcified fpirit rifes in thin fubtile vapours, which 

 condenfe upon the fides of the recipient in ttraight ftris ; 

 thcfe are fucceeded by white fumes, which form either irre- 

 gular ftriat, or large round drops like oil ; at the firft ap- 

 pearance of which, the procefs is either to be ftopped, or the 

 receiver changed. The fpirit which thefe fumes afford, very 

 different from the dulcified one, has a pungent acid fmell, 

 like the fumes of burning fulphur : on its furface is found a 

 fmall quantity of oil, called thefweet oil of vitriol of Hoff- 

 man, of a ftrong, penetrating, and very agreeable fmell, 

 readily diffoluble in fpirit of wine, to a large proportion of 

 •which it communicates the fmell andtafte of the aromatic or 

 dulcified fpirit. The College of Edinburgh, in order to fe- 

 curc agaitdl any acidity in the dulcified fpirit, ordered it to be 

 reftilicd, by mixing it with an equal meafure of water, in 

 every pint of which a drachm of fait of tartar has been dif- 

 folved, and drawing off the fpirit again by a gentle heat. 

 This College, in their laft Pharmacopeia, have manifeftly 

 (hewn how little they conceive the acid to enter as a confti- 

 tuent part of this preparation, and at the fame time have di- 

 refted an effeftual method of preventing its prefence in it. 

 1 hey order the acidum vilriolicum •ulnofum, vulgo fpiritus vi- 

 Irioli dulcis, to be made by fimply mixing one part of vitriolic 

 ether with two of reftificd fpirit. See Sulphuric Ether, 

 and Spirit of Ether. 



This fpirit, taken from ten to eighty or ninety drops, 

 ftrengthens the ftomach and digellivc powers, relieves flatu- 

 lencies, promotes urine, and, in many cafes, abates fpafmo- 

 dic ftriftures, and procures reft. It is not effentially dif- 

 ferent from the celebrated mineral anodyne liquor of Hoff- 

 man ; to which it is frequently, by the author himfclf, di- 

 refted as a fubftitute. Sec Liquor mineralis anodynus, Ethe- 

 real Sf\v.vr, and Compound Hpimr of Elher. 



The dulcified fpirit is fonictimes ufed as a mwiftruum for 

 certain refinous and bituminous bodies, which are more diffi- 

 cultly and languidly afted upon by pure vinous fpirits. It 

 is often mixed with aromatic and ftomachic tinfturcs, in cafc» 

 where the ftomach is too weak to bear the acid elixirs above- 

 mentioned : eight ounces are commonly added to a pint of 

 the officinal aromatic tinfture ; or the ingredients of the 

 aromatic tinfture are infufed in the dulcified acid, inftcad of 



Vol. XXXVII. 



common rcaified fpirit, in order to form the fweet elixir of 

 vitriol. A medicine of this kind was formerly in great 

 efleem, under the name of Figoni's volatile elixir of vitriol, 

 prepared by macerating, in feme dulcified fpirit of vitriol, 

 free from acidity, a fmall quantity of mint-leaves carefully 

 dried, till the fpirit has acquired a fine green colour : and to 

 prevent the neceffity of filtration, during which the more vo- 

 latile parts would exhale, the mint may be fufpended in the 

 fpirit in a fine cloth. If tlie dulcified fpirit, redified from 

 a folution of fixed alkaline fait, be fhaken with equal its 

 quantity of a like folution, and the mixture fuffered to reft, 

 an ethereal fluid rifes to the furface, and great part of the 

 dulcified fpirit may be recovered again from the remainder 

 by diftillation. Dr. Hadley obtained the largeft portion 

 of ether, by ufing the ftrongeft vitriolic acid of the (hops 

 with equal its quantity, by meafure, of fpirit of wine, and 

 diftilling immediately by a heat fufficient to make the mixture 

 boil. By this management, from three pints of oil of vi- 

 triol, and fix pints of redified fpirit of wine, he obtained 

 two pints and a half of the ether. 



The vitriolic acid faturates a larger quantity of fixed 

 alkaline falts than any of the other acids, and diflodges from 

 them fuch other acids as have been previoufly combined with 

 them. Of the ftrong fpirit, or oil of vitriol, about five 

 parts are fufficient for eight of the common vegetable fixed 

 alkalies. The neutral fait thus obtained is of a bitterifti 

 tafte, very difficultly foluble in water, and fcarcely fufible 

 in the fire : in fmall dofes, as a fcruple, or half a drachm, it 

 is an ufeful aperient : in larger ones, as four or five drachms, a 

 mild "cathartic. This fait has been commonly prepared with 

 the alkali obtained from tartar, and hence called vitriolated 

 tartar, and fometinies fal enixum, and arcanum dupltcatum. 

 Some dilute the oil of vitriol with fix times the quantity of 

 warm water, and drop into it a folution of the alkaline fait 

 till no effervefcence cnfues : others ufe vitriol in fubftancc, 

 which being diffolved in boiling water, any alkaline fait, 

 gradually fuperadded, till the effervefcence ceafcs, abforbs 

 the pure acid, and tlirows down the metallic bafis of the 

 vitriol : one part of the alkali is nearly fufficient for two of 

 the vitriol. 



With the mineral fixed alkali, this acid forms compound 

 falts of a more bitter tafte, fomewhat lefs purgative, and much 

 eafier of folution, than that with vegetable alkalies: with 

 volatile alkalies, a very pungent ammoniacal fait, whofe me- 

 dicinal effefts are not well known. The ftrong acid, boiled 

 on argillaceous earths to drynefs, corrodes a portion of them, 

 and concretes with them into an auftcre ftyptic fait. Calca- 

 reous earths it does not diffolve into a liquid ftate, but may 

 be combined with them, by precipitation from other acids, 

 into an indiffoluble concrete, fcemingly of no medicinal 

 aAivity. Among metallic bodies, it diffolvcs zinc and iron 

 readily j copper, filver, quickfilver, lead, and tin, very dif- 

 ficultly : it is fitted for aAing on the two firft by dilutioa 

 with three or four times its quantity of water: the others 

 require the undiluted acid, and a heat fufficient to make it 

 boil ; when, the more phlegmatic parts exhaling, fo much 

 of the pure acid matter remains combined with the metal* as 

 to render them, in part at leaft, diffoluble in water. 



The principal u(e of green vitriol is in dyeing, and in the 

 making of ink. When the vitriol is diffolved in water, tlic 

 iron contained in it becomes black by the addition of an in- 

 fufion of gall-nuts. Mr. Lemery, the younger, in order to 

 account for tliis blacknefs, imagines, that as the vitriol, of 

 which ink is made, is iron diflolved by an acid, and inti- 

 mately mixed wnth it, and as galU arc an alkali or abforbent, 

 this alkali, meeting the acids which hold the iron diffolved, 

 Q q unitM 



