XXXVI. Another as yet more easier way of preparing Aq. Regis for extraction.
Because silver doth always in this operation bewray its being impregnated with gold, which is to be separated by Aq. fortis, the solution of silver is also fitly used to extract after this manner.
Pour the said solution into Aq. Regis which hath extracted gold, that the silver may attract the greatest part thereof to it self. But the same Aq. Regis may again extract other gold, and be attracted by the solution of silver.
But if there should be no solution of silver in readiness, the gold extracted is con-centred with and the operation is perfected by the means or after the manner abovesaid, by driving the spirit out of the and by reducing it in a Furnace, called by the Germans Stichofen, as was said before.
N. B. Aq. fortis being dissolved therein, or poured on or into Aq. Regis, or the nitrous spirit of Salt, it adds an increase and strength to the Aq. Regis, because Aq. fortis doth corroborate the spirit of Salt better than Salt Peter.
XXXVII. How the Calx of silver, which hath fished out gold by Aq. Regis, is to be recovered.
When the solution of silver is poured into Aq. Regis, and the chiefest part of the gold is extracted; rest is so long granted unto it, that the Calx of the silver may settle to the bottom, and afterwards the Aq. Regis by pouring it forth is separated, cleared from the Calx of the silver, again to be used for a new extraction; unless perhaps as much of iron had been admixed with it, in which case the white Calx of the silver is put into some Cloath laid in an earthen or glass Tonnel, and hot water is to be poured on it, to take away with it the Aq. Regis, which is left in the Calx of the silver. The remaining water is to be pressed out of the Towel or Cloath, and the Calx dried, and reduced in the secret Crucible, or is made use of in the con-centring of into silver or gold, viz. gold and silver.
XXXVIII. After what manner precipitated silver is to be reduced without a loss of its weight.
Seeing the greatest fugacity is procured unto this Calx of silver, so that its former body cannot be restored unto it in common Crucibles without great loss, this discommodity cannot after a more convenient manner be prevented than by that which follows.
Mix thou an equal weight of with this volatile Calx, and cast it into a close bright burning Crucible, that is narrow above, and broad beneath; the which after thou hast covered with a Cover, and well fenced with the lute of Wisedom, thou shall melt the matter together, nothing whereof shall depart into smoke, neither shall so much as the least of it pierce through the Crucible, and all the Silver which the gold received is by this means attained without any loss.