544 BOOK XI. 



foreman of the works mixes these thorns with other precious thorns. The 

 hearth-lead which remains in the middle of the crucible, and the hearth 

 material which absorbs silver-lead, is mixed with other hearth-lead which 

 remains in the cupellation furnace crucible ; and yet some cakes, made rich 

 in this manner, may be placed again in the cupellation furnaces, together 

 with the rest of the silver-lead cakes which the refiner has made. 



The inhabitants of the Carpathian Mountains, if they have an abundance 

 of finely crushed copper^^ or lead either made from " slags," or collected 

 from the furnace in which the exhausted liquation cakes are dried, or 

 litharge, alloy them in various ways. The " first " aUoy consists of two 

 centumpondia of lead melted out of thorns, litharge, and thorns made 

 from hearth-lead, and of half a centumpondiiim each of lead collected in 

 the furnace in which exhausted liquation cakes are " dried," and of copper 

 minutum, and from these are made liquation cakes ; the task of the smelter is 

 finished when he has made forty liquation cakes of this kind. The 

 " second " alloy consists of two centumpondia of litharge, of one and a 

 quarter cenhmipondia of de-silverized lead or lead from " slags," and of half 

 a centumpondiiim of lead made from thorns, and of as much copper minuttim. 

 The " third " alloy consists of three centumpondia of Utharge and of half a 

 centumpondium each of de-silverized lead, of lead made from thorns, and of 

 copper minutum contusum. Liquation cakes are made from all these alloys ; the 

 task of the smelters is finished when they have made thirty cakes. 



The process by which cakes are made among the Tyrolese, from which 

 they separate the silver-lead, I have explained in Book IX. 



Silver is separated from iron in the following manner. Equal portions of 

 iron scales and filings and of stibium are thrown into an earthenware crucible 

 which, when covered with a lid and sealed, is placed in a furnace, into 

 which air is blown. When this has melted and again cooled, the crucible 

 is broken ; the button that settles in the bottom of it, when taken out, 

 is pounded to powder, and the same weight of lead being added, is mixed 

 and melted in a second crucible ; at last this button is placed in a cupel 

 and the lead is separated from the silver.^® 



There are a great variety of methods by which one metal is separated 

 from other metals, and the manner in which the same are alloyed I have 

 explained partly in the eighth book of De Natura Fossilium, and partly I will 

 explain elsewhere. Now I will proceed to the remainder of my subject. 



^^Parliculis aeris tusi. Unless this be the fine concentrates from crushing the material 

 mentioned, we are unable to explain the expression. 



'^This operation would bring down a button of antimony under an iron matte, by 

 de-sulphurizing the antimony. It would seem scarcely necessary to add lead before cupel- 

 lation. This process is given in an assay method, in the Probierbiichlein (folio 31) 50 years 

 before De Re MetalUca : " How to separate silver from iron : Take that silver which is 

 " in iron plechen (plachmal), pulverize it finely, take the same iron or plec one part, spiesglasz 

 " (antimony sulphide) one part, leave them to melt in a crucible placed in a closed windtofe.n. 

 " When it is melted, let it cool, break the crucible, chip off the button that is in the bottom, 

 " and melt it in a crucible with as much lead. Then break the crucible, and seek from the 

 " button in the cupel, and you will find what silver it contains." 



END OF BOOK XI. 



