1lead, and in four cakes of this kind there are three centumpondía of copper and
twelve centumpondía of lead. The lead which is liquated therefrom weighs
about ten centumpondía, in each centumpondíum of which there is a quarter
of a libra and more than a semí-uncía of silver, or seven uncíae; a bes, or
seven uncíae and a semí-uncía, of silver remain in the exhausted liquation
cakes and in the liquation thorns.
twelve centumpondía of lead. The lead which is liquated therefrom weighs
about ten centumpondía, in each centumpondíum of which there is a quarter
of a libra and more than a semí-uncía of silver, or seven uncíae; a bes, or
seven uncíae and a semí-uncía, of silver remain in the exhausted liquation
cakes and in the liquation thorns.
Against the second long wall in the second part of the building, whose
area is eighty feet long by thirty-nine feet wide, are four furnaces in which
the copper is alloyed with lead, and six furnaces in which “slags” are re
smelted. The interior of the first kind of furnace is a foot and three palms wide,
two feet three digits long; and of the second is a foot and a palm wide and a foot
three palms and a digit long. The side walls of these furnaces are the same
height as the furnaces in which gold or silver ores are smelted. As the whole
room is divided into two parts by upright posts, the front part must have,
first, two furnaces in which “slags” are re-melted; second, two furnaces in
which copper is alloyed with lead; and third, one furnace in which “slags” are
re-melted. The back part of the room has first, one furnace in which “slags”
are re-melted; next, two furnaces in which copper is alloyed with lead; and
third, two furnaces in which “slags” are re-melted. Each of these is six feet
distant from the next; on the right side of the first is a space of three feet
and two palms, and on the left side of the last one of seven feet. Each pair of
furnaces has a common door, six feet high and a cubit wide, but the first and
the tenth furnace each has one of its own. Each of the furnaces is set in an arch
of its own in the back wall, and in front has a forehearth pit; this is filled with
a powder compound rammed down and compressed in order to make a crucible.
Under each furnace is a hidden receptacle for the moisture,11 from which a
vent is made through the back wall toward the right, which allows the
vapour to escape. Finally, to the right, in front, is the copper mould into
which the copper-lead alloy is poured from the forehearth, in order that
liquation cakes of equal weight may be made. This copper mould is a digit
thick, its interior is two feet in diameter and six digits deep. Behind the
second long wall are ten pairs of bellows, two machines for compressing them,
and twenty instruments for inflating them. The way in which these should
be made may be understood from Book IX.
area is eighty feet long by thirty-nine feet wide, are four furnaces in which
the copper is alloyed with lead, and six furnaces in which “slags” are re
smelted. The interior of the first kind of furnace is a foot and three palms wide,
two feet three digits long; and of the second is a foot and a palm wide and a foot
three palms and a digit long. The side walls of these furnaces are the same
height as the furnaces in which gold or silver ores are smelted. As the whole
room is divided into two parts by upright posts, the front part must have,
first, two furnaces in which “slags” are re-melted; second, two furnaces in
which copper is alloyed with lead; and third, one furnace in which “slags” are
re-melted. The back part of the room has first, one furnace in which “slags”
are re-melted; next, two furnaces in which copper is alloyed with lead; and
third, two furnaces in which “slags” are re-melted. Each of these is six feet
distant from the next; on the right side of the first is a space of three feet
and two palms, and on the left side of the last one of seven feet. Each pair of
furnaces has a common door, six feet high and a cubit wide, but the first and
the tenth furnace each has one of its own. Each of the furnaces is set in an arch
of its own in the back wall, and in front has a forehearth pit; this is filled with
a powder compound rammed down and compressed in order to make a crucible.
Under each furnace is a hidden receptacle for the moisture,11 from which a
vent is made through the back wall toward the right, which allows the
vapour to escape. Finally, to the right, in front, is the copper mould into
which the copper-lead alloy is poured from the forehearth, in order that
liquation cakes of equal weight may be made. This copper mould is a digit
thick, its interior is two feet in diameter and six digits deep. Behind the
second long wall are ten pairs of bellows, two machines for compressing them,
and twenty instruments for inflating them. The way in which these should
be made may be understood from Book IX.
The smelter, when he alloys copper with lead, with his hand throws into
the heated furnace, first the large fragments of copper, then a basketful of
charcoal, then the smaller fragments of copper. When the copper is melted
and begins to run out of the tap-hole into the forehearth, he throws litharge
into the furnace, and, lest part of it should fly away, he first throws
charcoal over it, and lastly lead. As soon as he has thrown into the furnace
the copper and the lead, from which alloy the first liquation cake is made, he
again throws in a basket of charcoal, and then fragments of copper are thrown
over them, from which the second cake may be made. Afterward with a
rabble he skims the “slag” from the copper and lead as they flow into the
forehearth. Such a rabble is a board into which an iron bar is fixed; the
the heated furnace, first the large fragments of copper, then a basketful of
charcoal, then the smaller fragments of copper. When the copper is melted
and begins to run out of the tap-hole into the forehearth, he throws litharge
into the furnace, and, lest part of it should fly away, he first throws
charcoal over it, and lastly lead. As soon as he has thrown into the furnace
the copper and the lead, from which alloy the first liquation cake is made, he
again throws in a basket of charcoal, and then fragments of copper are thrown
over them, from which the second cake may be made. Afterward with a
rabble he skims the “slag” from the copper and lead as they flow into the
forehearth. Such a rabble is a board into which an iron bar is fixed; the
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