WASHING, OR HYDRAULICKING. 25 1
mixture
of clay and wood-ashes, and securely clamped, the fire is lighted and
the heat gradually raised, a dark-red heat being all that is necessary
to thoroughly volatilÂize the quicksilver. Towards the end of the
operation the heat is raised to a cherry-red color, at which it is kept
until distillation ceases. The retort is allowed to graduÂally cool,
and when cold is opened.
During
the operation the condensing-coil at the back of the retort should be
kept cool by a continuous supply of fresh water entering from the lower
end of the box which contains it, whilst the discharge of warm water is
effected above.
The retorted bullion is cut or broken in pieces and melted in a well-annealed black-lead crucible, and the gold cast into bars.
