398 BOOK IX. 



Or to a libra of the powder prepared from such metalliferous 

 concentrates, is added a libra each of salt, of saltpetre, of argol, and of 

 glass-galls, and it is heated until it melts. When cooled and crushed, it is washed, 

 then to it is added a libra of silver, a third of copper filings, a sixth of htharge, 

 and it is Ukewise heated again until it melts. After the button has been 

 purged of slag, it is put into the cupel, and the gold and silver are separated 

 from the lead ; the gold is parted from the silver with aqua valens. Or else 

 a libra of the powder prepared from such metaUiferous concentrates, 

 a quarter of a libra of copper filings, and two librae of that second powder'^ 

 which fuses ores, are heated until they melt. The mixture when cooled is again 

 reduced to powder, roasted and washed, and in this manner a blue powder is 

 obtained. Of this, and silver, and that second powder which fuses ores, a 

 libra each are taken, together with three librae of lead, and a quarter of a 

 libra of copper, and they are heated together untU they melt ; then the 

 button is treated as before. Or else a libra of the powder prepared from 

 such metalliferous concentrates, half a libra of saltpetre, and a quarter of a 

 libra of salt are heated until they melt. The alloy when cooled is again 

 crushed to powder, one libra of which is absorbed by four pounds of molten 

 silver. Or else a libra of the powder made from that kind of concentrates, 

 together with a libra of sulphur, a libra and a half of salt, a third of a libra of 

 salt made from argol, and a third of a libra of copper resolved into powder 

 with sulphur, are heated until they melt. Afterward the lead is re-melted, 

 and the gold is separated from the other metals. Or else a libra of the 

 powder of this kind of concentrates, together with two librae of salt, half a 

 libra of sulphur, and one libra of Htharge, are heated, and from these the 

 gold is melted out. By these and similar methods concentrates containing 

 gold, if there be a small quantity of them or if they are very rich, can be 

 smelted outside the blast furnace. 



If there be much of them and they are poor, then they are smelted in the 

 blast furnace, especially the ore which is not crushed to powder, and particularly 

 when the gold mines yield an abundance of it^*. The gold concentrates mixed 

 with htharge and hearth-lead, to which are added iron-scales, are smelted in the 

 blast furnace whose tap-hole is intermittently closed, or else in the first or the 

 second furnaces in which the tap-hole is always open. In this manner an 



'^hese powders are described in Book VII., p. 236. It is difficult to say which the 

 second really is. There are numbers of such recipes in the Probierbiichlein (see Appendix B), 

 with which a portion of these are identical. 



^^A variety of methods are involved in this paragraph : ist, crude gold ore is smelted 

 direct ; and, gold concentrates are smelted in a lead bath with some addition of iron — which 

 would simply matte off — the lead bullion being cupelled ; 3rd, roasted and unroasted pyrites 

 and cadniia (probably blende, cobalt, arsenic, etc.) are melted into a matte ; this matte is 

 repeatedly roasted, and then re-melted in a lead bath ; 4th, if the material " flies out of the 

 furnace " it is briquetted with iron ore and lime, and the briquettes smelted with copper 

 matte. Three products result : (a) slag ; (h) matte ; (c) copper-gold-silver alloy. The 

 matte is roasted, re-smelted with lead, and no doubt a button obtained, and further matte. 

 The process from this point is not clear. It appears that the copper bullion is melted with 

 lead, and normally this product would be taken to the liquation furnace, but from the text it 

 would appear that the lead-copper bullion was melted again with iron ore and pyrites, in 

 which case some of the copper would be turned into the matte, and the lead alloy would be 

 richer in gold and silver. 



