6d., per 250 lb.; it makes a very excellent fuel
for smelting purposes, smouldering and maintaining steadily the low heat
required for subliming the mercury from the amalgam. Beneath the furnace
is a vault containing a wrought-iron water-tank, B, into which the open
mouth of the retort, C, projects downward and is submerged below the
water. For charging the retort, the water-tank is placed on a trolly; and
standing upright on a stool inside the tank is placed the pina, or conical
mass of silver amalgam, which is held together by being built up on a
core-bar fitted with a series of horizontal disks. The trolly is then run
into the vault, and the water-tank containing the pina is lifted by
screw-jacks, so as to raise the pina into the retort, in which position
the tank is then supported by a cross-beam. The sublimed mercury is
condensed and collected in the water; and on the completion of the process
the tank is lowered, and the spongy or porous cone of silver is withdrawn
from the retort. The subliming furnaces are ranged in a row, and
communicate by lines of rails with the weigh-house.
* * * * *
INTERESTING FACTS ABOUT PLATINUM.
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