Year: 1864

At q meeting Of the Chemical eoeisty in,


London, some three yearB since, IN inter


esting paper was reid on deteHi6ratd kold,


by Mr.. N. Warrington. BE found thatS


large quantity Of gold sent from the Bank


of England was singularly, deficient IN


ductility !; 1t wasso "rotten" that it could


not be rolled or subjected to the usual pro-


cess of coming. He found by anllytis


that the specimen contained 92' per cent.


of gold, per cent. Of silver, and 2 per


cent of tin, and a small proportion Of am


timony. The presence Of this latter metal


was supposed to be the cause OF the alter.


alton in the usual mechanical character Of


the gold, and it was no easy matter to ex-


tract it economically without loss Of the


precious metal. After SexerAlexperiments


MIR. Warrington found that oxide Of cop


per when melted with the gold, in the pro.


portion Of about ten per cent, removed


the antimony the copper parting with It's


oxide to the antimony, WHICH then rose 70
the surface as powder, and could be cleo.
ed off. When, however, this process was.
attempted on large scale by the metal
lurgist at the mint, it was not found to
answer, and Mr.. Warrington was again
applied to. The gold had been melted in
the usual black lead or plumbago cruci-
bles, the carbon of which had combined
with the oxygen, and thus prevented the
proper action Of the oxyd Of copper on the
anthony present. On the substitution Of
clay crucibles for those of black lead. the
process was found to be very eficacious,
and the difficulty was removed. Mr.. War
nngton having observed in the course Of
his paper that there was difficulty in ae-
counting for the presence Of the antimony,
another member stated that when at the
Australian gold fields, he noticed large
quantities of almost pure antimony In
veins close to the quartz from whence the
gold was obtained, therefore there could
be but little doubt how the gold became
deteriorated. In papers read by other
members of the society. they stated, as re-
suit of experiments on large scale, that
gold is to certain extent volatilized dur
ing the progress Of cupellation,'a small
proportion Of the metal having been found
deposited in the fues of the furnace; and
that gold is also in slight degree soluble
in pure nitric or nitrous acids. In the
course of the discussion, after the reading
of these papers, one gentlemen mentioned
that he was in Australia soon after the
introduction of the quartz-crushing ma
chimes, when he observed great difference
in the amount of the produce Of the ANAL
gamated gold on different days; and ON
examining the tailings," or refuse Of the
mill, he perceived a quantity Of gold had
passed through without amalgamating
with the quicksilver. This led him at
once to suspect that the surface Of the gold
was covered with some unctuous substance
that obstructed its combination with the
mercury, and on treating it with an alkali,
he found that the metals readily combined.
He consequently recommended the mix
ture of wood ashes with the powdered
quartz, by which means the daily produce
Of gold has been equalized, and in some
instances greatly increased. On after
wards subjecting the tailings to the same
process, more gold was extracted from the
refuse than had been obtained when the
powdered quartz was first operated on. he