Year: 1874

II was established in 1854 and has had
since then constantly increasing business.
AT present the deposits are made through
the banks. The bullion is received in all
forms, gold dust, bars, iewelry, amalgams,
and so forth The deposits are all made
in the weigh-room, whers they are duly
weighed. Payments are, Of course, not
made to the depositors until the Assaysr
has made his report as to the quantity Of
pure gold in their deposits. For deposits
Of gold payments are made either in gold
bars or in coin, according to the option of
the depositor The first thing is to attach
a number to each deposit, and this num-
Der follows it through all the stages and
processes through which it may pass. The
process of melting is very simple, the bull
lion being simply placed in crucibles, which
are placed in furnace at something like
white heat. The liquid gold is then
poured into shapes, and the number with
which it starts is subsequently, stamped
upon it. At this Stage the gold contains,
of course, a huge quantity of base matter.
Jewelry, for instance, which is deposited
for melting and refining seldom contains
thirty per cent. of pure gold, this being
esteemed in such case rather high aver.
age. The gold Of jewelry is, however, the
least valuable kind deposited. The first
thing to be done 10 the matter Of refining
gold is to put it through process known
as granulation This is effected by mix.
ing two-thirds Of silver with one of gold
The result Of this process is that the mixed
gold aud silver takes the shape of compar
atiyely small grains or PARTICLES and the
object of so dividing it is that when fol
the purpose Of publication the gold i.
brought into contact with sulphuric acid, q
larger surface of the metal shall be ex
posed to its action. The separation of the
silver from the gold is effected in this way
The granulated metal is put into large
iron kettles and boiled in sulphuric acid
The result is that the silver becomes united
with the acid, forming sui ulphate of silver
1t is held in solution, and in this form j,
carried off through a syphon to tanks in :
room down stairs, where the silver is after
ward precipitated. The gold is subsc
quently subjected to several other baths oi
sulphuric acid until it is thoroughly sepa
rated from the silver. It is then placed
in filter and subjected to the action o.
warm water At this stage it simply re
semblcs muddy deposit, and has not thu
slightest metallic lustre. 1t is subsequently
dried, and hydraulic pressure is brought
to bear on it so as to squeeze the water out
of it thoroughly. 1t is afterward cast int
bars, and is thoroughly mixed in the pro
cess. When in liquid state, bone-dust i,
thrown on the surface, and this takes NJ
its impurities, which are afterward skim
med off, When the bars are cast, a slice
is cut of each end, and these arc submit.
ted to two assayers, who ale not in com
munication and who report separately
Their reports, besides determining the
value Of the gold, check each other. The
gold is now in condition to put upon
the market. Meanwhile the silver which is
held in solution in the sulphuric acid is
carried into tanks in which are copper
blocks Their contact with the sulphuric
acid produces sulphate of copper, and the
silver is precipitated. In all the processes
carried on in the Assay Office, there Is
nothing wasted. Even the sulphurous
fumes are carried into condensers, and are
turned into sulphuric acid, to be again
used for refining The weighing at the
Assay Office is done with the most fraction
al minuteness, and the calculations Of the
Office, which are Of the most intricate and
delicate kind, are performed in distinct
department.