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BOOK XI.
foreman of the works mixes these thorns with other precious thorns. Thehearth-lead which remains in the middle of the crucible, and the hearthmaterial which absorbs silver-lead, is mixed with other hearth-lead whichremains in the cupellation furnace crucible ; and yet some cakes, made richin this manner, may be placed again in the cupellation furnaces, togetherwith the rest of the silver-lead cakes which the refiner has made.
The inhabitants of the Carpathian Mountains, if they have an abundanceof finely crushed copper 35 or lead either made from “ slags,” or collectedfrom the furnace in which the exhausted liquation cakes are dried, orlitharge, alloy them in various ways. The “ first ” alloy consists of twocentumpondia of lead melted out of thorns, litharge, and thorns madefrom hearth-lead, and of half a centumpondium each of lead collected inthe furnace in which exhausted liquation cakes are “ dried,” and of copperminutum, and from these are made liquation cakes; the task of the smelter isfinished when he has made forty liquation cakes of this kind. The“ second ” alloy consists of two centumpondia of litharge, of one and aquarter centumpondia of de-silverized lead or lead from “ slags,” and of halfa centumpondium of lead made from thorns, and of as much copper minutum.The “ third ” alloy consists of three centumpondia of litharge and of half acentumpondium each of de-silverized lead, of lead made from thorns, and ofcopper minutum contusum. Liquation cakes are made from all these alloys ; thetask of the smelters is finished when they have made thirty cakes.
The process by which cakes are made among the Tyrolese, from whichthey separate the silver-lead, I have explained in Book IX.
Silver is separated from iron in the following manner. Equal portions ofiron scales and filings and of stibium are thrown into an earthenware cruciblewhich, when covered with a lid and sealed, is placed in a furnace, intowhich air is blown. When this has melted and again cooled, the crucibleis 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 mixedand melted in a second crucible ; at last this button is placed in a cupeland the lead is separated from the silver . 36
There are a great variety of methods by which one metal is separatedfrom other metals, and the manner in which the same are alloyed I haveexplained partly in the eighth book of De Natura Fossilium, and partly I willexplain elsewhere. Now I will proceed to the remainder of my subject.
3b Particulis aeris tusi. Unless this be the fine concentrates from crushing the materialmentioned, we are unable to explain the expression.
s6 This operation would bring down a button of antimony under an iron matte, byde-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 yearsbefore De Re Metallica : “ 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 windtofen.“ 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.