1anyone coming at an inopportune
moment might disturb his thoughts when
they are intent on the work. It is also necessary for him to place his balances
in a case, so that when he weighs the little buttons of metal the scales may
not be agitated by a draught of air, for that is a hindrance to his work.
they are intent on the work. It is also necessary for him to place his balances
in a case, so that when he weighs the little buttons of metal the scales may
not be agitated by a draught of air, for that is a hindrance to his work.
Now I will describe the different things which are necessary in assaying,
beginning with the assay furnace, of which one differs from another in
shape, material, and the place in which it is set. In shape, they may be
round or rectangular, the latter shape being more suited to assaying ores.
The materials of the assay furnaces differ, in that one is made of bricks,
another of iron, and certain ones of clay. The one of bricks is built on a
chimney-hearth which is three and a half feet high; the iron one is placed
in the same position, and also the one of clay. The brick one is a cubit high,
a foot wide on the inside, and one foot two digits long; at a point five digits
above the hearth—which is usually the thickness of an unbaked2 brick—
an iron plate is laid, and smeared over with lute on the upper side to prevent
it from being injured by the fire; in front of the furnace above the plate is a
mouth a palm high, five digits wide, and rounded at the top. The iron plate
beginning with the assay furnace, of which one differs from another in
shape, material, and the place in which it is set. In shape, they may be
round or rectangular, the latter shape being more suited to assaying ores.
The materials of the assay furnaces differ, in that one is made of bricks,
another of iron, and certain ones of clay. The one of bricks is built on a
chimney-hearth which is three and a half feet high; the iron one is placed
in the same position, and also the one of clay. The brick one is a cubit high,
a foot wide on the inside, and one foot two digits long; at a point five digits
above the hearth—which is usually the thickness of an unbaked2 brick—
an iron plate is laid, and smeared over with lute on the upper side to prevent
it from being injured by the fire; in front of the furnace above the plate is a
mouth a palm high, five digits wide, and rounded at the top. The iron plate
A—OPENINGS IN THE PLATE. B—PART OF PLATE WHICH PROJECTS BEYOND
THE FURNACE.
has three openings which are one digit wide and three digits long, one is at
each side and the third at the back; through them sometimes the ash falls
from the burning charcoal, and sometimes the draught blows through the
chamber which is below the iron plate, and stimulates the fire. For this
reason this furnace when used by metallurgists is named from assaying, but
when used by the alchemists it is named from the wind3. The part of the
iron plate which projects from the furnace is generally three-quarters of a
has three openings which are one digit wide and three digits long, one is at
each side and the third at the back; through them sometimes the ash falls
from the burning charcoal, and sometimes the draught blows through the
chamber which is below the iron plate, and stimulates the fire. For this
reason this furnace when used by metallurgists is named from assaying, but
when used by the alchemists it is named from the wind3. The part of the
iron plate which projects from the furnace is generally three-quarters of a