Elmore bulletin. [volume] (Rocky Bar, Idaho) 1889-1906, 1893-02-11
ASSAYING FINE GOLD.
HOW IMPURITIES ARE DETECTED
IN A SOLID GOLD BRICK.

themists Laboratory.
About o'clock ia the morning two men
entered the Mitchell building. and getting
Into the elevator mounted to the sixth |
floor and went straight TO the rooms Of the |
United States assay Office. One of them |
carried In his hand bundle the size OF a !
thin brick, wrapped in paper. He laid it !
down on the counter in the Office aud slow |
ly unwrapped the bundle. IL was a gold
brick. The clerk took the bullion, and
stepping across the floor placed 1t Ia one OF
the pans OF large pair of scales Then he
closed the office windows aud placed some
weights In the other When II balanced
nicely he went 20 his desk, took out a
blank form and wrote to the effect that
400 ounces OF gold bullion had been re
eeivcd from the 81. Louis Smelling and
refining works at the United States as
say Office, TO be assayed. This was signed
by T. {. Je@ett, the assayer ia charge, and
the men wen, away. This is the first stem
the government takes toward obtaining
precious metal for coming purposes.
IL Is extremely interesting To follow this
process OF assaying through all the steps
until the value Of the gold is determined
and the governments check given for il.
While Clerk Rex was filling out the re-
ceipt Mr.. Jewett explained the marvellous
delicacy OF the scales. Their weighing ca
paclty Is 1000 ounces, and 1t is possible to
Indicate by them difference in weight OF
one gram. To illustrate 80 that this NAV
he easily grasped, two heavy men coult. be
placed In one Of the pans. and 10y removing
PIN from the coat OF one Of them the bal.
ance would be changed. Still il would be
dlihcult TO obtain the exact weight of the
men, owing to the constant change in the
mems bodies by perspiratiun and other
causes
After the bullion's weight was deter
mined ON these scales IL was taken TO IA.
furnace room and placed in "A blacklead
crucible. This was SET on a firebrick rest.
ing on CRATE aud lire built around il
The fuel used is mixture Of anthracite
coal and charcoal. After an hours melt
ing, during which time it was Frequently
stirred with plumbago poker. to which
gold does not cling, II sample Of the metal
was dipped ont with an ordinary clay nine
ana poured into a small mold The a say
4 y made from this, a. IL takes 50 much
longer Tor the larger quantity to cool. A
piece OF the sample WAS cut on, pounded
+ anu then rolled through u roller of tool
steel looking something like a clothes
| ~ringer, To make II thin. " hen this WINS
done, Herman, the German who aids the
assdyer IN his work, handed the Thin
goiuen strip 70 him and then went bac. to
| Tue furnace room 10 pour out the molten
thousands into the big mold.
Mr.. Je"ett cut the strip into small
pieces, and then, forming little lead cornu.
copins OF uniform weight, dropped into
two of them 800 milligrams Zone sixteenth
OF an ounce of accurately weighed gold To
be aSSayed. Into two others he nut the
same quantity Of absolutely pure gold
Enough silver was then added 10 make the
proportion of silver to gold two TO one. as
TINS proportion Is necessary in order that
the gold should separate from the silver
when boiled in nitric acid.
There is in all gold a certain amount Of
silver and II Is owing to its presence and
certain other foreign substances that the
color Of gold varies The idcn that gold
found in California or Australia il OF such
color because found there is IA mistaken
one.
After the silver had been added the
leaden cornucupias were squeezed un and
each one placed in what Is called a cupel
A cupel is a little cup made of sheen bones
burned To ashes, ground fine, moistened
and nodded into mold an inch long. an
inch III diameter. with a cup shaped de
preston at one end, The cupels were
placed IN "A small furnace with n tempera.
ture OF about l,l00 degs. centigrade, and
when heated to n white heat the little
metal chunks were laid by the aid of tongs
one ia each cupel They melted, sputterel
and dubbed, and then began to grow
smaller. In about ten minutes they were
taken out and all the lead and foreign sub
stances had been absorbed BY the cuneI
leaving only the noble metals in littls
round balls. When these were boiled IN
nitric acid the silver passed into nitrate OF
silver and the gold was left in its pure
state. by this WAS found the ratio of pure
gold In the bullion.
The weighings Of pure gold are used as a
check to any particular conditions of heat
etc. The assayer knows the constitution.
weight and specific gravity OF the pure
gold used. When it is weighed after the
heating process, II it has changed il
weight, II is fair to suppose that il is ow
ing TO the conditions of heat or strength OF
acid, and that the same influences have
been at work ON the assay gold. BY al
lowing for this in the assay gold true re
suit is reached.
The next step was to find the weight OF
the gold and silver together The lead
cornucOpas were again filled with certain
weights of the pure and assay gold, but nc
silver added. When melted in the eupels
the baser metals disappeared as before
and the gold and silver were left to
gether BY subtraeting from the weight
OF gold and silver the weight OF the gold
the exact weight OF the silver was oh,
tanned. OF course the proportion is usually
very small II the amount Is not suflicien,
To pay for extracting, the government does
not pay for IL. aud charges nothing for ex
traction.
The entire amount OF gold In the bullion
is found by multiplying its weight by the
proportion Of the gold This is reduced "a
standard or coin gold by multiplying this
amount by ten and dividing by nine, as
standard gold is only so per cent. fine, and
the depositor is paid by the government
$50 per ounce of standard metal, equal Ia
5000 for tine gold. The assay fee is one.
eighth Of ] per cent. OF the total value Of
fine gold, the melting fee is one dollar. and
the alloy charge about one cent ON 500
aud after this is deducted the asSayer
hands check To the owner OF the gold.
The entire time occupied by this com.
plicated operation was from a. m. until
D m. only four hours.-St. Louis Repub-
lie
Impaled by "A Buck.
Postmaster Peacock tells US, says a
Florida paper, that son OF Indian BILLY
Jewel, better known AS Billy Key West. q
young man twenty-one years old, met his
ii - A.