1runs down
on to the lower layer of wood; and when this is consumed by
the fire, the metal is collected. If necessity demand, it is melted over and
over again in the same manner, but it is finally melted by means of wood
laid over the large crucible, the slabs of lead being placed upon it.
the fire, the metal is collected. If necessity demand, it is melted over and
over again in the same manner, but it is finally melted by means of wood
laid over the large crucible, the slabs of lead being placed upon it.
The concentrates from washing are smelted together with slags (fluxes?)
in a third furnace, of which the tap-hole is always open.
in a third furnace, of which the tap-hole is always open.
It is worth while to build vaulted dust-chambers over the furnaces,
especially over those in which the precious ores are to be smelted, in order
that the thicker part of the fumes, in which metals are not wanting, may be
caught and saved. In this way two or more furnaces are combined under the
same vaulted ceiling, which is supported by the wall, against which the
furnaces are built, and by four columns. Under this the smelters of the
ore perform their work. There are two openings through which the fumes
rise from the furnaces into the wide vaulted chamber, and the wider this is the
more fumes it collects; in the middle of this chamber over the arch is an opening
three palms high and two wide. This catches the fumes of both furnaces,
which have risen up from both sides of the vaulted chamber to its arch, and
have fallen again because they could not force their way out; and they thus
pass out through the opening mentioned, into the chimney which the Greeks
call καπνοδόχη, the name being taken from the object. The chimney has
thin iron plates fastened into the walls, to which the thinner metallic sub
stances adhere when ascending with the fumes. The thicker metallic
substances, or cadmia,25 adhere to the vaulted chamber, and often
harden into stalactites. On one side of the chamber is a window in which
are set panes of glass, so that the light may be transmitted, but the fumes
kept in; on the other side is a door, which is kept entirely closed while the
ores are being smelted in the furnaces, so that none of the fumes may escape.
It is opened in order that the workman, passing through it, may be enabled
to enter the chamber and remove the soot and pompholyx26 and chip off
especially over those in which the precious ores are to be smelted, in order
that the thicker part of the fumes, in which metals are not wanting, may be
caught and saved. In this way two or more furnaces are combined under the
same vaulted ceiling, which is supported by the wall, against which the
furnaces are built, and by four columns. Under this the smelters of the
ore perform their work. There are two openings through which the fumes
rise from the furnaces into the wide vaulted chamber, and the wider this is the
more fumes it collects; in the middle of this chamber over the arch is an opening
three palms high and two wide. This catches the fumes of both furnaces,
which have risen up from both sides of the vaulted chamber to its arch, and
have fallen again because they could not force their way out; and they thus
pass out through the opening mentioned, into the chimney which the Greeks
call καπνοδόχη, the name being taken from the object. The chimney has
thin iron plates fastened into the walls, to which the thinner metallic sub
stances adhere when ascending with the fumes. The thicker metallic
substances, or cadmia,25 adhere to the vaulted chamber, and often
harden into stalactites. On one side of the chamber is a window in which
are set panes of glass, so that the light may be transmitted, but the fumes
kept in; on the other side is a door, which is kept entirely closed while the
ores are being smelted in the furnaces, so that none of the fumes may escape.
It is opened in order that the workman, passing through it, may be enabled
to enter the chamber and remove the soot and pompholyx26 and chip off