In certain places, as at Freiberg in Meissen, the upper part of the
cupellation furnace is vaulted almost like an oven. This chamber is four
feet high and has either two or three apertures, of which the first, in
front, is one and a half feet high and a foot wide, and out of this flows
the litharge; the second aperture and likewise the third, if there be three,
are at the sides, and are a foot and a half high and two and a half feet wide,
in order that he who prepares the crucible may be able to creep into the
furnace. Its circular bed is made of cement, it has two passages two feet high
and one foot wide, for letting out the vapour, and these lead directly through
from one side to the other, so that the one passage crosses the other at right
angles, and thus four openings are to be seen; these are covered at the top
by rocks, wide, but only a palm thick. On these and on the other parts
of the interior of the bed made of cement, is placed lute mixed with straw,
to a depth of three digits, as it was placed over the sole and the plates of
copper and the rocks of that other furnace. This, together with the ashes which
are thrown in, the master or the assistant, who, upon his knees, prepares
the crucible, tamps down with short wooden rammers and with mallets
likewise made of wood.
cupellation furnace is vaulted almost like an oven. This chamber is four
feet high and has either two or three apertures, of which the first, in
front, is one and a half feet high and a foot wide, and out of this flows
the litharge; the second aperture and likewise the third, if there be three,
are at the sides, and are a foot and a half high and two and a half feet wide,
in order that he who prepares the crucible may be able to creep into the
furnace. Its circular bed is made of cement, it has two passages two feet high
and one foot wide, for letting out the vapour, and these lead directly through
from one side to the other, so that the one passage crosses the other at right
angles, and thus four openings are to be seen; these are covered at the top
by rocks, wide, but only a palm thick. On these and on the other parts
of the interior of the bed made of cement, is placed lute mixed with straw,
to a depth of three digits, as it was placed over the sole and the plates of
copper and the rocks of that other furnace. This, together with the ashes which
are thrown in, the master or the assistant, who, upon his knees, prepares
the crucible, tamps down with short wooden rammers and with mallets
likewise made of wood.
A—FURNACE SIMILAR TO AN OVEN. B—PASSAGE C—IRON BARS.
D—HOLE THROUGH
WHICH THE LITHARGE IS DRAWN OUT. E—CRUCIBLE WHICH LACKS A DOME. F—THICK
STICKS. G—BELLOWS
WHICH THE LITHARGE IS DRAWN OUT. E—CRUCIBLE WHICH LACKS A DOME. F—THICK
STICKS. G—BELLOWS
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