$74 Of tb* Vitriol 



fatty, bituminous mineral; as may be fecn, in 

 particular, from the woody alum-ores of Commo- 

 dau, the fhlvery ores of Schwemfel, and the earthy 

 of Belgern ; but, as appears from its refolution, 

 alum pofTeiles it in a quite unformed, white, ftub- 

 born form, moft probably referable to a calca- 

 rious fort. It fometimes acquires, in diftillation, 

 a foreign, either a vegetable or animal fattinefs ; 

 as, when in the courfe of the operation, the vefTels 

 happen to have cracks, through thefe the fattinefs 

 infinuates into the work from the fumes of the 

 wood or coah, or when with defign fomething in- 

 flammable is added, and then 'tis called fpiritus 

 vitrioli fulphureus* as the acid vitriol fait, and the 

 phlogifton, exhibit therein fomething fulphu- 

 reous. 



The metallic earth of the vitriol is procured ei- 

 ther by means of diftillation, and remains like a 

 brown- red powder, a caput mortuum^ at the bot- 

 tom of the retort % to which head alfo belongs the 

 calcination of vitriol in other vefTels, and for other 

 purpofes : it may alfo be obtained by means of 

 precipitation, which is performed by an alcali, 

 but, at the fame time, earthy particles precipitat- 

 ing out of the alcali, a pure metallic vitriol-earth 

 is not procured. 



In this earth, after diftillation, fomething lodges 

 that may be extracted with hot water, and has the 

 form of a white fait, called gilla vitrioli ; not to 

 be confidered as a third conftituent part of vitriol^ 

 nor as the vitriol itfelf employed, but as fomething 

 different, a more elaborated, and thus a whiter 

 vitriol \ in regard it, in part, ftill confifts of the 

 fame acid fait as was already drawn off from vitri- 

 \h and alfo it contains a portion of metallic earth, 



for 



