4o8 BOOK IX. 



Pyrites, when they contain not only copper, but also silver, are smelted 

 in the manner I described when I treated of ores of silver. But if they are 

 poor in silver, and if the copper which is melted out of them cannot easily be 

 treated, they are smelted according to the method which I last explained. 



Finally, the copper schists containing bitumen or sulphur are roasted, 

 and then smelted with stones which easily fuse in a fire of the second order, 

 and are made into cakes, on the top of which the slags float. From 

 these cakes, usually roasted seven times and re-melted, are melted out 

 slags and two kinds of cakes ; one kind is of copper and occupies the 

 bottom of the crucible, and these are sold to the proprietors of the works in 

 which silver is parted from copper ; the other kind of cakes are usually 

 re-melted with primary cakes. If the schist contains but a small amount of 

 copper, it is burned, crushed under the stamps, washed and sieved, and 

 the concentrates obtained from it are melted down ; from this are made 

 cakes from which, when roasted, copper is made. If either chrysocolla or azure, 

 or yellow or black earth containing copper and silver, adheres to the schist, 

 it is not washed, but is crushed and smelted with stones which easily 

 fuse in fire of the second order. 



Lead ore, whether it be molybdaena*'' , pyrites, (galena ?) or stone from 

 which it is melted, is often smelted in a special furnace, of which I have 

 spoken above, but no less often in the third furnace of which the tap-hole 

 is always open. The hearth and forehearth are made from powder containing 

 a small portion of iron hammer-scales ; iron slag forms the principal flux 

 for such ores ; both of these the expert smelters consider useful and to 

 the owner's advantage, because it is the nature of iron to attract lead. If 

 it is molybdaena or the stone from which lead is smelted, then the lead runs 

 down from the furnace into the forehearth, and when the slags have been 

 skimmed off, the lead is poured out with a ladle. If pyrites are smelted, 

 the first to flow from the furnace into the forehearth, as may be seen at 

 Goslar, is a white molten substance, injurious and noxious to silver, for it 

 consumes it. For this reason the slags which float on the top having been 

 skimmed off, this substance is poured out ; or if it hardens, then it is taken 

 out with a hooked bar ; and the walls of the furnace exude the same substance*^. 



*'This expression is usually used for hearth-lead, but in this case the author is apparently 

 confining himself to lead ore, and apparently refers to lead carbonates. The German Trans- 

 lation gives pleyschweiss. The pyrites mentioned in this paragraph may mean galena, as 

 pyrites was to Agricola a sort ot genera. 



*^{Excoquilur) . . . "si vera pyrites, prima e fornace, tit Goselariae videre licet, in 

 " catinum defluit liquor quidam candidus, argento inimicus et nocivus ; id enim comburit : 

 " quo circa recrementis, quae supernatant, detraciis efjunditur : vet induratus conto uncinato 

 " extrahitur : eundem liquorem parietes fornacis exudant." In the Glossary the following 

 statement appears : " Liquor candidus primo e fornace defluens cum Goselariae excoquitur 

 "pyrites, — kobclt ; quern parietes fornacis exudant, — conterfei." In this latter statement 

 Agricola apparently recognised that there were two different substances, i.e., that the sub- 

 stance found in the furnace v/a\h — conterfei — was not the same substance as that which 

 first flowed from the furnace — kobclt. We are at no difficulty in recognizing conterfei as 

 metallic zinc ; it was long known by that term, and this accidental occurrence is repeatedly 

 mentioned by other authors after Agricola. The substance which first flowed into the fore- 

 hearth presents greater difficulties ; it certainly was not zinc. In De Natura Fossilium (p. 

 347), Agricola says that at Goslar the lead has a certain white slag floating upon it, the 

 " colour derived from the pyrites (pyriten argenteum) from which it was produced." Pyriten 

 argenteum was either marcasite or mispickel, neither of which offers much suggestion ; nor are 

 we able to hazard an explanation of value. 



Historical Notk on Zinc. The history of zinc metallurgy falls into two distinct 



