But it is certain that whatsoever Minerals and Metals do retain with them sharp spirits, are as yet immature, and may be ripened by those spirits, that they may bestow Gold and Silver, as hath been already said, and shall as yet more largely be spoken to.
LVII. Out of wild or course Minerals, or veins of Lead, admitting of no melting, out of which no good Lead, much less Gold or Silver, can be drawn, how to extract not onely Lead, but also Gold and Silver with profit.
As we have said above, that some Minerals or Veins of Copper do appear in Mines, the which by reason of Lapis Calaminaris or Zink do refuse all melting, and can be by no fire reduced: So also we here admonish, that Minerals of Lead are found, the which do indeed contain much Lead, but by reason of the Lapis Calaminaris, Zink, and a sulphureous Sand being admixed with them, they cannot be overcome by any melting, for these matters do take away a ready flowing from the Lead, and do cause that such Minerals, which for the most part together with Lead, do also hide not a little of Gold and Silver, are cast away as altogether unfit, and unprofitable, whenas notwithstanding very much profit might be received from them after this manner.
Let the Mineral by pounding be broken in small pieces, and in my little secret Furnace which I have fitted for the calcining of Minerals, let it be roasted with bright burning Coals, that the gross Sulphur may conceive a flame, and burn. If in time of operation the matter should gather it self into heaps or knobs, and in co-heaping should make round Pellets, it being taken out of the Furnace, let it again be beaten, be set upon live Coals and roasted, and these labours be so often repeated, untill all the Sulphur shall be consumed, and the Mineral doth no longer co-heap it self into knobs, but being made bright burning hot like dead ashes; it no longer sends forth a sulphureous stink. At length out of these ashes being well washed, a dead and unprofitable matter separates its self from the good and metallick earth, the which being melted by it self in a Furnace called by the Germans Stichofen, becomes a flowable Lead which containeth Gold and Silver.
But if the Mineral be so stubborn that it altogether refusing all melting, could not by it self be reduced, and nevertheless contain Gold and Silver, something of Litharge is to be added to that metallick earth, which procures a flux unto it, and yields that Gold and Silver bearing Lead, which by the common operation wholly refuseth to offer it self.
LVIII. Another way teaching by the help of Salt and Fire to draw Silver and Gold with great profit, out of all stubborn or rude and untamed metallick earths, in whose Veins Lead, Copper, Gravel, or course Sands, Iron, or Lapis Calaminaris have for the most part conjoyned in Society, and which do deny all profit by vulgar operations.
As Fire burns up every gross and combustible Sulphur in Mines or Minerals, that these do at length subject themselves unto melting, and do render Metals easie to be hammered: so also Salt fixeth, and makes constant whatsoever volatile body endeavours to flie away into the air, that it may afford a ripened, melted, and profitable Metal. For that cause such Minerals common Salt being added as was abovesaid, are to be roasted in live Coals, that that devouring gross Sulphur may vanish by burning with a flame, and that together also the Metal it self may be promoted to maturity, and so that by this very thing, good Gold and Silver may be separated, whenas notwithstanding otherwise, not any one should obtain so much as the least thereof out of these very Minerals.
Such an amendment and changing the more imperfect Metals into the more perfect ones, may be attained by the help of Salt and Fire.
If therefore common Salt and gross Fire are able to perform this in Minerals, what shall not these, not common but secret Fires of Salts effect, in trans-changing Metals already pure, into more pure and subtile ones?