. De re metallica. Metallurgy; Mineral industries. 250 BOOK VII. copper is not wholly liquefied ; if he finds this is the case, he asjain places a large piece of charcoal in the crucible, and replaces the glowing charcoal which had been removed, and again blows the bellows for a short time. When all the copper has melted he stops using the bellows, for if he were to continue to use them, the fire would consume part of the copper, and then that which remained would be richer than the cake from which it had been cut ; this is no small mistake. Therefore, as soon as the copper has become sufficie
. De re metallica. Metallurgy; Mineral industries. 250 BOOK VII. copper is not wholly liquefied ; if he finds this is the case, he asjain places a large piece of charcoal in the crucible, and replaces the glowing charcoal which had been removed, and again blows the bellows for a short time. When all the copper has melted he stops using the bellows, for if he were to continue to use them, the fire would consume part of the copper, and then that which remained would be richer than the cake from which it had been cut ; this is no small mistake. Therefore, as soon as the copper has become sufficiently liquified, he pours it out into a httle iron mould, which may be large or small, according as more or less copper is melted in the crucible for the purpose of the assay. The mould has a handle, Ukewise made of iron, by which it is held when the copper is poured in, after which, he plunges it into a tub of water placed near at hand, that the copper may be cooled. Then he again dries the copper by the fire, and cuts off its point with an iron wedge ; the portion nearest the point he hammers on an anvi' and makes into a leaf, which he cuts into A—Iron mould Others stir the molten copper with a stick of linden tree charcoal, and then pour it over a bundle of new clean birch twigs, beneath which is placed a wooden tub of sufficient size and full of water, and in this manner the copper is broken up into little granules as small as hemp seeds. Others employ straw in place of twigs. Others place a broad stone in a tub and pour in enough water to cover the stone, then they run out the molten copper from the crucible on to the stone, from which the minute granules roll off; others pour the molten copper into water and stir it until it is resolved into granules. The fire does not easily melt the copper in the cupel unless it has been poured and a thin leaf made of it, or unless it has been resolved into granules or made into fihngs ; and if it does not melt, all the labour
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