Of the Mineral of Liege, Yielding Both Brimstone and Vitriol, and the Way of Extracting Them Out of It, Used at Liege

This Story Sir R. Moray affirmed to have received from the Earl of Weynes, Brother in Law to the Lord Sinclair, as it was written to him from Scotland. Of the Mineral of Liege, yielding both Brimstone and Vitriol, and the way of extracting them out of it, used at Liege. The Account of this Mineral, and of the way of extracting both Brimstone and Vitriol out of it, was procured from Liege, by the lately mentioned Sir Robert Moray, and by him communicated to the Royal Society, as follows. The Mineral, out of which Brimstone and Vitriol are extracted, is one and the same, not much unlike Lead-ore, having also oft times much Lead mingled with it, which is separated from it by picking it out of the rest. The Mines resemble our English Coal-Mines, dugg according to the depth of the Mineral, 15, 20, or more fathoms, as the Vein leads the Workmen, or the subterranean waters will give them leave, which in Summer so overflow the Mines, that the upper waters, by reason of the drought, not sufficing to make the Pumps goe, the Work ceases. To make Brimstone, they break the Stone or Ore into small pieces, which they put into Crucibles made of Earth, five foot 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 betwixt them, that the Fire may come at them all, each having its particular Furnace or Oven. The Brimstone being dissolved by the violence of the heat, drops out at the small end of the Crucible, and falls into a Leaden-Trough or Receptacle, common to all the said Crucibles, through which there runs a continual Rivulet of cold water, conveyed thither by Pipes for the cooling of the dissolved Sulphur, which is ordinarily four hours in melting. This done, the Ashes are drawn out with a crooked Iron, and being put into an Iron Wheel-barrow, are carried out of the Hutt, and being being laid in a heap, are covered with other elixed or drained Ashes, the better to keep them warm; which is reiterated, as long as they make Brimstone. To make Coperas or Vitriol, they take a quantity of the said Ashes, and throwing them into a square planked pit in the Earth, some four foot deep, and eight foot square, they cover the same with ordinary water, and let it lye twenty four hours, or until an Egge will swim upon the liquor, which is a sign, that it is strong enough. When they will boil this, they let it run through Pipes into the Kettles, adding to it half as much Mother-water, which is that water, that remains after boiling of the hardened Coperas. The Kettles are made of Lead, 4½ foot high, 6 foot long, and 3 foot broad, standing upon thick Iron Bars or Grates. In these the Liquor is boiled with a strong Coal-fire, twenty four hours or more, according to the strength or weakness of the Lee or Water. When it is come to a just consistence, the fire is taken away, and the boiled liquor suffered to cool somewhat, and then it is tapp'd out of the said Kettles, through holes beneath in the sides of them, and conveyed through wooden Conduits into several Receptacles, three foot deep and four foot long (made and ranged not unlike our Tan-pits) where it remains fourteen or fifteen days, or so long till the Coperas separate itself from the water, and becomes icy and hard. The remaining water is the above-mentioned Mother-water; and the elixed or drained Ashes are the Dreggs, or Caput mortuum, which the Lee, whereof the Vitriol is made, leaves behind it in the planked Pitts. A further Account of Mr. Boyle's Experimental History of Cold. In the first Papers of these Philosophical Transactions, some promise was made of a fuller account, to be given by the next, of the Experimental History of Cold, composed by the Honourable Mr. Robert Boyle; it being then supposed, that this History would have been altogether printed off at the time of publishing the second Papers.