The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1881-07-23

Tue manner 10 which the gold received
at the United States Assay Office in New
York IS tested IS described As follows -
The method is to take the gold on depOsi,
from the bankers or others who send il,
aud to give them a check on the sub-,reas-
ury after an assay had been made. Each
deposit ef gold is melted and cast into
bricks in every case before the assay Is
made. Two small quantities are then
ehisscled Of from two different bricks and
sent one to each Of the two men in the
assay room. Here seven grains aud 4
half OF each quantity are carefully weighed
out by each man on a separate pair Of
scales iucloscd in a glass case. This sew
en- and a-half grains corresponds with .
Freneh weight which has been divided
into thousand equal parts Each Of the
two assayers works separately, but Ia =
similar manner to the end Of the assay
Their results must agree 10 within very
small fraction. Each adds to the weighed
ed gold 4 definite quantity Of silver.
This Is done because the nitric acid to
which it is 10 be subjected viii not ferret
out very small quantities Of silver that arc
euveloped in the gold. bus If large
amount Of silver Is melted up wiih the
gold the acid can follow it into the mass
aud eat /, al out. The weighed particles
Of gold and silver are thea wrapped up 10
a little sheet Of pure lead OF q known
weight that is first twisted into the shape
Of . eornucopia 20 receive them. The Pei,
lex og gold aud silver aud lead Is then
melted ia,o 4 eupel, little porous white
cup made Of the ashes Of booze Pith- 4
daft Of ho, air passes over the melted
mass, aud this oxidires the lead, and the
presence Of the oxidiEed lead Tor some
unknown reason aids the oxidation Of the
copper mixed il ,he gold and carries II
down With iI ia q similarly mysterious way
into the pores Of the euPel There IS lei'
q little bultoa Of gold aud silver lying in
the bottom Of the eupeL This is ham
mered to knock of the scales Of oxide that
cling to il. and then rolled into a ribbon
nearly half az inch wide. This ribbon Is
eoiled up aud put into 4 iistie platinum
cup the sizs OF thimbls aud SC. into boil
ing nitric acid. The bottom Of the plat.
iaam cup Is perforated so that the boiling
aeid may eater aud get a fair ehaace
At the silver. IL viii not attack either
the gold in the ribbon nor the platinum
Of the cup. The coil Is boiled ten mia
utes, and then lifted out and boiled ten
minutes more in fresh acid. By this tine
their silver is al eaten ou, ofthe ribbon and
the gold is lel porous, which makes it 50
brittle that if it is pinehed the little eoil
will craekle iuto pieces in the fngeHs- IL
is accordingly subjected to just eaoagh
heat to cause the PARTICLES to adhere.
This little coil is aow pure gold. Il Is un-
polished and Of dull creamy color. Not
a particle Of the gold has been lost, but all
Of the alloys have been removed. Il Is
again carefully weighed Suppose that
whereas it originally weighed 1000 &c
cordins to the system Of weighing cx-
planned above, il now weighs s73. This
shows that the metal brought 10 to be as
saved contains S73 parts in 900 Of gold
or, 10 other words, 81 3-i0 per eent. Of il
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 addi-
tional quantity Of silver IS added 10 il for
the same reason that has been explained
I in the process Of assaying. Ii is then
melted and graduated by flirting the mol
ten gold from ladle upon the surface ol
water The idea is to make the gold fal
in sheet on the surface so that it vii
break up into little Aaky masses. Thit
granulated gold is then dried, aud for con
Yenienee of handling is pressed into cheese
shaped masses. These are cut up and the
pieces are put into boiling oil Of yitriol
The acid eats out the silver aud copper
which turns it blue. This blue liquid i,
drawn of with siphOn. The boiling i;
repeated several times, varying 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 cop.
per and silver is run into a tank, and weak
ened with the addition of water, the effect
of this simple process is to cause the acid
to let 20 Of the silver while it yet clings tc
the copper.
The blue liquid is now allowed to stand
in lead lined tank, in which are suspend
ed also many long strips of lead. On the
| lead beautiful blue crystals are formed
with points as sharp as needles, and who's,
scratch is poisonous. These crystals are
blue vitriol, or sulphate of copper, and ar,
sold as such for the making of paris greer
and other chemical products