The following instructions
apply to the treatment of very small buttons, to which the method is
more particularly applicable; but very little modification is needed for
the treatment of larger buttons. The smallest sized Berlin crucibles
answer admirably. They should be cleaned by treatment with hot and
strong sulphuric acid, followed by washing in distilled water; the
comfort and ease of working mainly depends on the thoroughness of this
cleaning. The crucible, one-third full with the first parting acid, is
heated on the hot plate until the acid is almost boiling. The flattened
and annealed button is dropped into it and the heating continued with,
at most, gentle boiling for a few minutes. The crucible is then filled
with distilled water, which cools it enough for easy handling; and when
the gold has settled the liquor is poured off along a glass rod into a
clean beaker. Any greasiness of the crucible makes itself felt here and
is very objectionable. The crucible is then one-third filled with the
second parting acid and the heating resumed, care being taken not to
raise the temperature too high; this should be continued much longer
than before, say for five or ten minutes or even longer according to the
size of the button. Distilled water is again added and, when it is
drained off, the washing with distilled water is twice repeated.
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