XXXII. After what manner out of Minerals being extracted, a true Salt-Peter may as yet be gotten with profit.
The minerals being after the said manner freed by extraction, they are to be co-mixed with an equal weight of calx vive and wood ashes, and cast together into an heap under some open gallery or room, that now and then it may be moistened with Urine, or in want of that with Rain-water, as oft as they shall be dryed.
In this operation the Aq. Regis, which remained in the minerals, and was not wholly extracted by the hot water by the help of the Urine or Rain-water, changeth the Salt in the calx vive into the best Salt-Peter, the which may be washed off with Rain-water, and boiled up after the wonted manner.
Therefore after the said minerals have been handled for half or a whole year after the said manner, and are by rinceing deprived of the Salt it self, they may again be (under an open Gallery or Roof so exposed to the air, that Rain come not at it) collected into an heap and be handled after the former manner, for the supplying (in their own time) new Salt Peter, the which may be done for many years together. So also from that Aq. Regis which could not be drawn forth from the minerals, a profit is received.
The cause of this Salt Peter, its being made, is this, because the Aq. fortis, or Aq. Regis, or Spirit of Nitre in the same Waters, contains as it were the seed of Salt Peter, it obtains that nature, that like an Herb it may take an increase from other Salts, and be multiplied; whence perhaps the old proverb arose, to sow Salt, which thing the ignorant have received with mock, saying after what sort can Salt be sown and multiplied, when it is solved and drawn from Rain-water? But it hath lain hid from those, what kind of Salt it is, and after what manner it is to be sown; the which we have here demonstrated, also the saying of the Ancient Philosophers, asserting that Salt may be sown and multiplied like Vegetables.
As to what pertains to those sharp waters, whereby gold is extracted out of minerals, by what skill they are to be handled as also without loss, yea that they may render that gold with profit; the following operations are to be observed.
XXXIII. A way shewing the extraction of a volatile and fixed Gold out of the Water, from which the Minerals are withdrawn, and the profit which may be received by that Water.
The best way is this, into the solution of gold, or into the water which containeth gold, pour in the solution of Lune or Saturn more or less, even as you suspect more or less of gold to be in that water: As for example. Let there be in the water two or three half ounces of gold, dissolve thou therefore about two or three half ounces of silver, or lead, in aq. fortis, and pour this solution into the water containing the gold, be it more or less, mix them well together by shaking or stirring, that the water may obtain the form of milk; after they have settled in quietness, shake or stir them again, and repeat this motion for divers times the space of one hour, and at length suffer all quietly to settle to the bottom. Separate all the clear water from the sediment by pouring it out, and strain the sediment itself through a filtre, that the water may be wholly separated from the silver.
This silver is to be dried, and reduced into its former body, after the manner which shall by and by follow.
N. B. If the silver or lead had not extracted all the gold, the which may easily happen, yet that gold is not lost, for because sweet water whereby the Aq. Regis is weakened is present, the which now remains unfit for another use of extracting out of minerals; now by the solution of Lune or Saturn deprived of their gold, a sharp Lixivium made of wood-ashes, and Calx vive may be poured on the same, with which a little is to be added or admixed. For do precipitate or fix all gold in solutions.