Year: 1873

I huWcFeT, SOOu wears Ou, IOC aileT ueiu


in the room few minutes the visitor ex


pericnces nothing more disagreeable than


u slight Utilization of the throat In each


of these pots has been placed "melt," +"


or $50 pounds of mixed granulated me


tai, as prepared in the melting room and


the pots is then filed with sulphuric acid,


which is kept az boiling point for an en-


tire day. The acid separates the gold


from the silver, precipitating the former,
aud holding the latter in solution. The
gold which is found at the bottom of the


pot, after the liquid has been drawn of,


has the appearance of course red sand
and is more or less mixed with silver, to free
it from which it is necessary to subject it
to six or eight boilings in sulphuric acid,
occupying in all about week, by the
end of which time pure gold OF about
nine hundred and ninety eight one thou
sandths in fneness is obtained in the
form OF very 6ue dust. Between each
boilding it is necessary to wash the gold
IN hot water, aud run it through filter.
10 order to take out any sulphate of sill
yer that may remain. After this wash
ing the gold dust is placed in circular
mold, and subjected to hydraulic pres.
sure of 200 tons, in order to remove all
moisture. The dust thus pressed into
cakes is again melted, aud cast into bars
Of from one Of to six or ten pounds in
weight, when it is stamped with the Of
fetal stamp of the Assay Office, and is
ready for market. Each operation, or
rather series of operations, thus conduct
ed in the separating room, aud occupying
about week, results in the production
of about $50 pounds, or $50, 900 worth of
fine gold.


But We have not yet done with the Sc
parating room. After each boiling of
the gold and silver in sulphuric acid, the
liquid holding large. quantity of silver
in solution is run through pipes into tanks
beneath filled with cold water Coils of
steam pipes run round these tanks, and
bars of copper placed in the bottom
Steam is then let on and the liquid kept
boiling for two days, during which the
acid in the silver solution dissolves part
of the copper, precipitatiug the silver in
powder, looking like very fine silver sand.
The silver might be precipated in salt
water, by which means it would assume
the form of chlorine silver, having the
appearance of slackened lime, but the
chemical action of copper produces fine
metallic silver, from which all the base
metals are washed out, and it is then tax
en- to the melting room and cast into bars
of solid silver, ready for the market. The
liquid from which the siver has thus been
eliminated contains large quantities of
copper, and is then run off into other
tanks and allowed to cool, when the cop
per crystallizes, forming blue vitriol,
which, after being boiled second time,
is dried and barreled for market. Near.
ly 500 pounds of pure silver are thus OBJ.
tanned from each series of operations 10
the separating room. In melting. all the
dross or baser metals, called the fux,
floats on the suface of the molten gold or
silver, aud is taken of on eartheu plates
This aux and the ashes from the furnace
are crushed and washed, and all the metal
that may remain in them is Obtained
Thus, 10 single "melt" of $50 pounds
of gold, scarcely single ounce Of pure
metal is lost, although, the regulations OF
the department allow sometiug more than
that quantity for waste. The workmen
in the separating room all wear large rub
Der gauntlets to protect their hands from
the action of the acid in which they have
to work. The fumes of the sulphur from
the pots in the separting room pass up
through long iron pipes into leaden con
deuser, where they pass through coke in
to a second and third condenser before
they are allowed to pass into the air, by
which time they are so free from sulphur
as to leave its presence almost iudisting-
uishable. e.-Ncw York Times.