1of the furnace into the
forehearth, is likewise dipped out with a ladle into
oblong copper moulds; in this way nine or ten cakes are made, which are
“dried,” together with bad exhausted liquation cakes, and from these
“dried” cakes yellow31 copper is made.
oblong copper moulds; in this way nine or ten cakes are made, which are
“dried,” together with bad exhausted liquation cakes, and from these
“dried” cakes yellow31 copper is made.
The cadmia,32 as it is called by us, is made from the
“slags” which the
master, who makes copper from “dried” cakes, draws off together with other
re-melted base “slags”; for, indeed, if the copper cakes made from such
“slags” are broken, the fragments are called cadmia; from this and yellow
copper is made caldarium copper in two ways. For either two parts of cadmia
are mixed with one of yellow copper in the blast furnaces, and melted; or, on
the contrary, two parts of yellow copper with one of cadmia, so that the
cadmía and yellow copper may be well mixed; and the copper which flows down
from the furnace into the forehearth is poured out with a ladle into oblong
copper moulds heated beforehand. These moulds are sprinkled over with char
coal dust before the caldarium copper is to be poured into them, and the same
dust is sprinkled over the copper when it is poured in, lest the cadmia and
yellow copper should freeze before they have become well mixed. With a
piece of wood the assistant cleanses each cake from the dust, when it is
turned out of the mould. Then he throws it into the tub containing hot water,
for the caldarium copper is finer if quenched in hot water. But as I have
so often made mention of the oblong copper moulds, I must now speak of
them a little; they are a foot and a palm long, the inside is three palms and a
digit wide at the top, and they are rounded at the bottom.
master, who makes copper from “dried” cakes, draws off together with other
re-melted base “slags”; for, indeed, if the copper cakes made from such
“slags” are broken, the fragments are called cadmia; from this and yellow
copper is made caldarium copper in two ways. For either two parts of cadmia
are mixed with one of yellow copper in the blast furnaces, and melted; or, on
the contrary, two parts of yellow copper with one of cadmia, so that the
cadmía and yellow copper may be well mixed; and the copper which flows down
from the furnace into the forehearth is poured out with a ladle into oblong
copper moulds heated beforehand. These moulds are sprinkled over with char
coal dust before the caldarium copper is to be poured into them, and the same
dust is sprinkled over the copper when it is poured in, lest the cadmia and
yellow copper should freeze before they have become well mixed. With a
piece of wood the assistant cleanses each cake from the dust, when it is
turned out of the mould. Then he throws it into the tub containing hot water,
for the caldarium copper is finer if quenched in hot water. But as I have
so often made mention of the oblong copper moulds, I must now speak of
them a little; they are a foot and a palm long, the inside is three palms and a
digit wide at the top, and they are rounded at the bottom.
The concentrates are of two kinds—precious and base.33 The first are
obtained from the accretions of the blast furnace, when liquation cakes are
made from copper and lead, or from precious liquation thorns, or from the
better quality “slags,” or from the best grade of concentrates, or from the
sweepings and bricks of the furnaces in which exhausted liquation cakes are
“dried”; all of these things are crushed and washed, as I explained in Book
VIII. The base concentrates are made from accretions formed when cakes
are cast from base thorns or from the worst quality of slags. The smelter
who makes liquation cakes from the precious concentrates, adds to them
three wheelbarrowsful of litharge and four barrowsful of hearth-lead and
one of ash-coloured copper, from all of which nine or ten liquation cakes
are melted out, of which five at a time are placed in the furnace in which
silver-lead is liquated from copper; a centumpondium of the lead which drips
from these cakes contains one uncia of silver. The liquation thorns are
obtained from the accretions of the blast furnace, when liquation cakes are
made from copper and lead, or from precious liquation thorns, or from the
better quality “slags,” or from the best grade of concentrates, or from the
sweepings and bricks of the furnaces in which exhausted liquation cakes are
“dried”; all of these things are crushed and washed, as I explained in Book
VIII. The base concentrates are made from accretions formed when cakes
are cast from base thorns or from the worst quality of slags. The smelter
who makes liquation cakes from the precious concentrates, adds to them
three wheelbarrowsful of litharge and four barrowsful of hearth-lead and
one of ash-coloured copper, from all of which nine or ten liquation cakes
are melted out, of which five at a time are placed in the furnace in which
silver-lead is liquated from copper; a centumpondium of the lead which drips
from these cakes contains one uncia of silver. The liquation thorns are