The Vancouver independent. (Vancouver, W.T. [Wash.]) 1875-1910, 1881-08-25
How Bullion Is Tested.

ceived at the United States Assay Office
in New York is treated is described as
follows: The method is to take the gold
on deposit from the bankers or others
who send it in, and to give them check
ON the sub-treasury after an assay had
been made. Each deposit OF gold is
melted and cast into bricks in every case
before the assay is made. Two small
quantities are then chlseled of from
two different bricks and sent one to each
of two men in the assay room. Here
seven grains and a half of each quantity
are carefully weighed out by each man
on q separate pair of scales inclosed in o
glass case. The seven and half grains
corresponds with French weight which
has been divided into thousand equal
parts. Each of the two assayers works
separately, but in q similar manner to
the end OF the assay. Their results must
agree to within very small fraction.
Each adds to the weighed gold def
mite quantity of silver. This is done be-
cause the nitric acid to which it is to be
subjected will not ferret out very small
quantities of silver that are enveloped
in the gold, but if large amount of sill
yer is melted up with the gold the acid
can follow it into the mass and eat it
all out. The weighed particles of
gold and silver are then wrapped up in
q little sheet of pure lead Of known
weight that is first twisted into the shape
of cornucopia to receive them. This
pellet of gold and silver and lead is then
melted into q cupel, a little porous white
cup made of the ashes of bone pith.
draft of hot air passes over the melted
mass, and this oxydizes the lead, and the
presence of the oxydized lead for some
unknown reason aids the oxidation OF the
copper mixed in the gold and carries it
down with it in q similarly mysterious
way into the pores of the cupel. There
is left little button of gold and silver
lying in the bottom of the cupel. This
is hammered to knock off the scales OF
oxide that cling to it, and then rolled
into ribbon nearly half an inch wide.
This ribbon is coiled up and put into
little platinum cup the size Of o thimble
and set into boiling nitric acid. The
bottom of the platinum cup is perforated
so that the boiling acid may enter and
get fair chance at the silver. 1t will
not attack either the gold in the
ribbon nor the platinum of the cup.
The coil is boiled ten minutes, and then
lifted out and boiled ten minutes more
in fresh acid. By this time the silver is
all eaten out of the ribbon, and the gold
is left porous, which makes it so brittle
that if it is pinched the little coil will
crackle into pieces in the fingers. 1t is
accordingly subjected to just enough
heat to cause the particles to adhere.
This little coil is now pure gold. 1t is
unpublished aud of q dull creamy color.
Not particle of the gold has been lost,
but ali of the alloys have been removed.
It is again carefully weighed. Suppose
that whereas it originally weighed 1000,
according to the system of weighing ex-
planned above, it now weighs only S73.
This shows that the metal brought in to
be assayed contains 873 parts in 1000 of
gold. or, in other words, 81 $40 per cent.
Of it only is pure.
All gold is melted before it is assayed,
and having been assayed it must be
melted again in order to be refined. An
additional quantity of silver is added to
1t for the same reason that has been ex-
planned in the process of assaying. 1t is
then melted and granulated by flirting
the molten gold from o ladle upon the
surface of water. The idea is to make
the gold fall in chest on the surface so
that it will break up into little fiaky
masses. This granulated gold is then
dried, and for convenience of haul.
ing is pressed into cheese shaped
masses. These are cut up and
the pieces are put into boiling oil OF
vitriol. The acid eats out the silver and
copper, which turns it blue. This blue
liquid is drawn of with q siphon. The
boiling is repeated several times, vary
ing in number according to the purity
required, after which the gold is melted
and run into brick-shaped masses to be
carried to the treasure-room.
The blue liquid which contains the
copper and silver is run into q tank, and
weakened with the addition of water.
The effect of this simple process is to
cause the acid to let go OF the silver
while it yet clings to the copper.
The blue liquid is now allowed to
stand in lead-lined tank, in which are
suspended also many long strips of lead.
On the lead beautiful blue crystals are
formed, with points % sharp as needles,
and whose scratch is poisonous. These
crystals are blue vitriol, or sulphate of
copper, and are sold as such for the
making of paris green and other chemi-
cal products.
When little Johnnie was first learning
to talk, he took special delight in re-
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