1copper
is not wholly liquefied; if he finds this is the case, he again 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 little 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, likewise 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 anvil and makes into a leaf, which he
cuts into pieces.
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 little 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, likewise 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 anvil and makes into a leaf, which he
cuts into pieces.
A—IRON MOULD. B—ITS HANDLE.
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 filings; and if it does not melt, all the labour has been undertaken
in vain. In order that they may be accurately weighed out, silver and lead
are resolved into granules in the same manner as copper. But to return
to the assay of copper. When the copper has been prepared by these
methods, if it is free of lead and iron, and rich in silver, to each centumpon
díum (lesser weights) add one and a half unciae of lead (larger weights). If,
however, the copper contains some lead, add one uncia of lead; if it contains
iron, add two unciae. First put the lead into a cupel, and after it begins
to smoke, add the copper; the fire generally consumes the copper, together
with the lead, in about one hour and a quarter. When this is done, the silver
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 filings; and if it does not melt, all the labour has been undertaken
in vain. In order that they may be accurately weighed out, silver and lead
are resolved into granules in the same manner as copper. But to return
to the assay of copper. When the copper has been prepared by these
methods, if it is free of lead and iron, and rich in silver, to each centumpon
díum (lesser weights) add one and a half unciae of lead (larger weights). If,
however, the copper contains some lead, add one uncia of lead; if it contains
iron, add two unciae. First put the lead into a cupel, and after it begins
to smoke, add the copper; the fire generally consumes the copper, together
with the lead, in about one hour and a quarter. When this is done, the silver
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