Idaho semi-weekly world. [volume] (Idaho City, Idaho Territory) 1875-1908, 1893-01-17
ASA WING FINE GOLD.
HOW IMPURITIES ARE DETECTED
m a SOLID GOLD BRICK.

= SOLID GOLD BRICK.
Following lnsot Gold Througt several
Stages = Extracting silver from ths
Prscious Metal laterestins steps IL !
chsnaistss laboratory.
About 2 o'clock In the morning two men
entered the Mitchell building, and rettlnr
into the elevator mounted 10 the slxth
door and went straight to the rooms 81 the
United States Assay office. One Of them
carried II his hand bundle the size 81
thin brick, wrapped in paper. He laid II
down on the counter in the Office an, slow
y unwrapped thesbundie. IL was 1 gold
brick. The clerk took the bullion. ard
stepping across the floor placed II in one q
the pans Of large pair Of scales. Then Is
closed the ONCE windows and placed some
weights IN the other. When IL balanced
nicely ne went to bis desk, took Out Z
blank form and wrote to the effect that
40 ounces OF gold bullion had been II
ceived from the 81. Louis Smelling and
Refining works at the United States ~
say ONCE, TO be assayed. This was signed
~ r. Y. Jewett. the assayer Ii, charge. md
the men wens away. This is the list stem
the government takes toward Obtaining
precious metal for coming purposes.
y " extremely interesting 10 follow. tbis
process Of aAsaying through All the stems
untn the value OF the gold u determined
ana tne governments check given for it,
While Clerk Rex was filling out the ~
ceipt MI. Jewett explained tie marvellous
oeiicacy Of the scales. Their weighing ca
pacity = 1000 ounces, and IL is possible q
Indicate ~ them difference in weight ~
one gram. To illustrate 40 that this NAV
pe easily grasped, two heavy men could be
placed IN one OF the pans. and by removing
PIN from the coat Of one Of them the boI.
snce would be changed. Still, it would IS
dimcuit TO obtain the exact weight OF the
men. owing to the constant change In tire
mems bodies by perspiration and other
After the bullion's weight was deter.
mined on these scales it was taken 10 r.
furnace room and placed in blacklend
cruclbie This was set on firebrick rest
Ing on CRATE and a fire built around Il
Inc fuel used is q mixture Of anthracite
coai and charcoal. After an hours melt
ing, during which time it was freouentIv
stirred with a plumbago poker, to which
goid does not cling, a sample Of the metal
was dlpped out with an ordinary CLAW nine
ana poured into a small mold. The assav
Is Rade from this, as it takes 40 much
loiser for the larger quantity to cool.
piece OF the sample was cut off, pounded
ana then rolled through a roller of tool
steei, looking something like a clothes
wringer. to make it thin. When this WAS
zone, Herman, the German who aids the
assayer IN his work, handed the thin
golden strip to him and then went BAG. to
tne furnace room to pour out the molten
thousands into the big mold.
Mr. Jewett cut the strip into small
pieces, and then, forming little lead cornu-
copias OF uniform weight, dropped into
Two OF them 800 milligrams Zone sixteenth
OF an ounce} OF accurately weighed gold TO
De assayed- Into two others he put the
same quantity of absolutely pure gold.
Enough silver was then added to 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 it is owing to its presence and
certain other foreign substances that the
color OF gold varies. The idea that gold
found in California or Australia is of snch
color because found there is a mistak on
one.
After the silver had been added the
leaden cornucopias were squeezed I'M and
each one placed in what is called a cuneI
A cupel is little cup made of sheep bones
burned to ashes, ground fine, moisteped
and nodded into mold an inch long. an
inch IN diameter, with cup shaped de-
preston at one end. The cupeis were
placed in small furnace with tempera-
lure of about LOO degs. centigrade. and
when heated to white heat the little
metal chunks were laid by the aid of tonps
'ne in each cupel. They melted, sputtered
and dubbed, and then began to grow
smaller. In about ten minutes thew were
Iaken out and all the lead and foreign sub
stances had been absorbed By the cunel
leaving only the noble metals in little
round balls. When these were boiled in
nitric acid the silver passed into nitrate ~
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
heck to any particular conditions of heat
tic. The assayer knows the constitution
weight and specific gravity of the pure
gold used. When it is weighed after the
heating process, il it has changed its
weight, it is fair to suppose that it is ow-
ng to the conditions of heat or strength Of
lcid, and that the same influences have
been at work on the assay gold. By al
owing for this in the assay gold true re-
'ult is reached.
The next step was to find the weight of
he gold and silver together. The lead
were again filled with certain
weights of the pure and assay gold, but no
liver added. When melted in the cupels
he baser metals disappeared as before.
md the gold and silver were left to-
yether. BY subtracting from the weight
# gold and silver the weight of the gold.
he exact weight of the silver was OBJ
aimed. OF course the proportion is usually
'ery small. II the amount is not sufficient
o pay for extracting, the government does
lot pay for it. and charges nothing for ex-
raction.
The entire amount of gold in the bullion
5 found by multiplying its weight by the
of the gold. This is reduced to
tandard or coin gold by multiplying this
mount by ten and dividing by nine, as
gold is only so per cent. fine, and
he depositor is paid by the government
s 60 per ounce of standard metal, equal to
2O.67 for fine gold. The assay fee is one
ighth Of per cent. of the total value of
Inc gold, the melting fee is one dollar, aud
he alley charge about one cent on 500,
nd after this is deducted the assayer
ands a check to the owner of the gold.
he entire time occupied by this com
licated operation was from a. m. until
l. M, only four hours.-St. Louis Repub-
&c.
inhaled bY n Ruck.