(Hence is it that this Work is an unheard of Operation, and doth almost exceed all belief, and from which there must an immense gain of necessity accrew, because Gold, Silver, and Copper may by this means be extracted out of their poor Metallick Earths without costs.
There remains yet one thing which is to be heedfully regarded in the precipitation of the Gold and Silver. A common Lixivium cannot precipitate all the Gold out of the Aqua Regis, and therefore I bid you add to the Lixivium some liquor of Flints, and this will also appear in my first Century.
Therefore it behoves every one, clearly to see whether or no he makes use of true and genuine Liquor of Flints in his Operation, that so he may not instead of it, use a bare simple Lixivium onely, and so commit a great errour, as it hath happened to some as I have been told.
But he that can’t make true and good liquor of Flints, or else has it not at hand, may substitute in its steed, common Spirit of Urine prepared in a Copper still, which together with the said liquor precipitates all the Gold out of the Aqua Regis.
N. B. But this Gold thus precipitated by Spirit of Urine, fulminates like Gun-powder, unless it be burnt with common Brimstone afore the Reduction, and that this fulminating faculty be taken away from it, which inconvenience the liquour of Flints is not wont to bring.
N. B. If there should be much Zink, Iron, or Lapis Calaminaris in the Oars of Gold or Silver, the Aqua Fortis or Aqua Regis would not all ascend by the Distillation, nor get increase; but some part thereof would stay with those Metallick Earths, and with the Lapis Calaminaris, &c. and by adhering thereunto be concentrated: but yet there would not be any loss by that, for by the pouring on a Lixivium of Wood-ashes, may it be turned into good Salt-peter, of as much value as may easily recompence the charges of the Aq. Fortis, or Aq. Regia.
Besides, you are likewise to observe this, that if there should be Copper admixt in the Oars of the Gold and Silver, the Aq. Fortis would extract the Copper too, as well as the Silver.
But now the nearest way of separating these two Metals from each other, is this, Let Spirit of Salt be poured to the Aq. Fortis, and it will precipitate all the Silver out of the Aq. Fortis, down to the bottom and the Copper will be left in the water; which if you put some Iron into, it will stick to the Iron, and by this means be gotten out of the water.
This water now, after the Metals are withdrawn from it, is fit to make new Salt-peter with, and by addition of Vitriol to yield a new Aq. Fortis by distillation.
Alkali Salts do in the Fusing bring the precipitated Silver to its former body, which otherwise is very fugacious.