TOL. I.J PHILOSOPHICAL TRANSACTIONS. gf 



Of the Mineral of Liege,* yielding both Brimstone and Vitriol, and 

 the Method, of extracting them out of it, as used at Liege. By Sir 

 Robert Moray. N" 3, p. Ab. 



The mineral, out of which both brimstone and vitriol are extracted, is not 

 much unlike lead ore, and has often much lead mingled with it, which is sepa- 

 rated by picking it from the rest. The mines resemble our English coal-mines, 

 dug, according to the depth of the mineral, 15, 20, or more fathoms. To make 

 brimstone, they break the ore into small pieces, and put it into earthen cruci- 

 bles five feet long, square and pyramid-wise. The entry is near a foot square. 

 These crucibles are laid sloping, eight undermost and seven above them, (as it 

 were between them) that the fire may come at them all, each having its particu- 

 lar furnace. The melted brimstone drops out at the small end of the crucible, 

 and falls into a leaden trough (common to all the said crucibles), through which 

 there runs a continual stream of cold water, conveyed thither by pipes, for the 

 purpose of cooling the fused sulphur, which is usually four hours in melting. 

 After this distillation of the sulphur, the' ashes (or residuum), being scraped out 

 of the crucibles, are employed (mixed with other lixiviated ashes) to make 

 copperas or vitriol ; for which purpose they are thrown into a square planked 

 pit in the earth, about four feet deep and eight feet square, and are covered 

 with water. In this they remain twenty-four hours, or until an egg will swim 

 upon the liquor, which is a sign that it is strong enough. When this liquor is 

 to be boiled, they let it run through pipes into the kettles, adding to it half as 

 much mother-water, i. e. the water which was left in previous crystallizations 

 of the vitriol. The kettles are made of lead, four feet and a half high, six feet 

 long, and three feet broad, and are placed upon iron grates. In these the liquor 

 is boiled with a strong coal fire twenty-four hours or more, till it acquires a 

 proper consistence ; when the fire is taken away, and the liquor, after being 

 suffered to cool a little, is let out through holes made in the sides of the kettles, 

 and conveyed through wooden conduits into several reservoirs three feet deep. 



Account of Mr. Boyle s Experimental History of Cold. iV" 3, p. 46. 



He shews, 



1 . That not only all sorts of acid and alcalizate salts, and spirits, even spirit 

 of wine, but also sugar, and sugar of lead mixed with snow, are capable of 

 freezing other bodies, and upon what account they are so. 



• This mineral is a pyrites, and the process here described for extracting sulphur and vitriol (sul- 

 phate of iron) from it, is used to this day. 



VOL. I. C 



