1the cadmía; this sweeping is done twice a
year.
The soot mixed with
pompholyx and the cadmia, being chipped off, is thrown down through
a long chute made of four boards joined in the shape of a rectangle,
that they should not fly away. They fall on to the floor, and are sprinkled
with salt water, and are again smelted with ore and litharge, and become
an emolument to the proprietors. Such chambers, which catch the metallic
substances that rise with the fumes, are profitable for all metalliferous
ores; but especially for the minute metallic particles collected by washing
crushed ores and rock, because these usually fly out with the fire of the
furnaces.
pompholyx and the cadmia, being chipped off, is thrown down through
a long chute made of four boards joined in the shape of a rectangle,
that they should not fly away. They fall on to the floor, and are sprinkled
with salt water, and are again smelted with ore and litharge, and become
an emolument to the proprietors. Such chambers, which catch the metallic
substances that rise with the fumes, are profitable for all metalliferous
ores; but especially for the minute metallic particles collected by washing
crushed ores and rock, because these usually fly out with the fire of the
furnaces.
I have explained the four general methods of smelting ores; now I
will state how the ores of each metal are smelted, or how the metal is obtained
from the ore. I will begin with gold. Its sand, the concentrates from
washing, or the gold dust collected in any other manner, should very often
not be smelted, but should be mixed with quicksilver and washed with tepid
water, so that all the impurities may be eliminated. This method I ex
plained in Book VII. Or they are placed in the aqua which separates
gold from silver, for this also separates its impurities. In this method we
see the gold sink in the glass ampulla, and after all the aqua has been drained
from the particles, it frequently remains as a gold-coloured residue at the
bottom; this powder, when it has been moistened with oil made from
argol27, is then dried and placed in a crucible, where it is melted with borax
or with saltpetre and salt; or the same very fine dust is thrown into molten
silver, which absorbs it, and from this it is again parted by aqua valens28.
will state how the ores of each metal are smelted, or how the metal is obtained
from the ore. I will begin with gold. Its sand, the concentrates from
washing, or the gold dust collected in any other manner, should very often
not be smelted, but should be mixed with quicksilver and washed with tepid
water, so that all the impurities may be eliminated. This method I ex
plained in Book VII. Or they are placed in the aqua which separates
gold from silver, for this also separates its impurities. In this method we
see the gold sink in the glass ampulla, and after all the aqua has been drained
from the particles, it frequently remains as a gold-coloured residue at the
bottom; this powder, when it has been moistened with oil made from
argol27, is then dried and placed in a crucible, where it is melted with borax
or with saltpetre and salt; or the same very fine dust is thrown into molten
silver, which absorbs it, and from this it is again parted by aqua valens28.
It is necessary to smelt gold ore either outside the blast furnace in a
crucible, or inside the blast furnace; in the former case a small charge of ore
is used, in the latter a large charge of it. Rudís gold, of whatever colour
it is, is crushed with a líbra each of sulphur and salt, a third of a líbra of copper,
crucible, or inside the blast furnace; in the former case a small charge of ore
is used, in the latter a large charge of it. Rudís gold, of whatever colour
it is, is crushed with a líbra each of sulphur and salt, a third of a líbra of copper,