Wilmington journal. [volume] (Wilmington, N.C.) 1844-1895, 1853-09-09
From the Washington Union.
A ssaying.

To crafty general curiosity as to the process of
assaying. will give in detail the method prac-
tsed in this country far it relates to coinage
Science has SO far perfected this method as to bring
to comparative uniformity the modes practised in
different codntres-the main difference being only
in the quantity of metal used for these trials. AS
the reduced value of bullion is exactly proportonate
to the degree of admixture with baser metals, nu-
merous methods had previously TO the one now in
use (been devised for ascertaning such admixture ;
but the uncertainty, tediousness, and expense at
tending these have found happy alternative and
succedaneum in the art of assaying practised
which unites the indispensable requisites of precis
ion, despatch, and cheapness In any certain weight
Of the subject of trial the question before the assay
er is: How much fine gold, or fine silver or of both,
does it contain? To ascertain this fact he weighs a
small portion with suitable exactness submits it to
the usual process of separating the alloy, CHS
it when the operation is completed, and makes his
report accordingly. This operation is performed in
the assay furnace which contains kind Of earthen
oven or mufle, within which are placed several
small vessels made of bone ashes, known by the
name of coppels, or little cups, which, when sufh-
GENTLY heated by the charcoal fire, with which the
furnace is filled, and which encloses the mufie on
all sides, receive each one assay wrapped in pro-
per quantity of thin lead These melting inmed-
atey together, the lead becomes gradually and in
part converted to glass. Serving menstruum
in the vitrifcation of the other base metals also,
these sink together into the porous substance of the
thoroughly refined. which finishes the process of a
silver assay If gold is the subject of trial: the
say piece is beat thin, made soft in the fire, and,
when rolled lightly together, is put into glass
sci containing aquafortis, previously heated
gentle fire. in which the silver is gradually dissolv-
ed and the gold left in state of purity, retaining
the form it possessed previous to the solution Of sill
YER. To secure the perfection of this process, the
proportion of silver to gold in the assay piece should
be as 2 or to l, which addition, when necessary,
is made before the gold assay is put the coppel
When mixture of gold and silver is the subject of
trial and the quantity of the latter exceeds that of
the former, it is called Uer parting, and if contra
wise, gold parting With the former the assayer
proceeds in all respects as he would with silver
assay, making his report all the fine metal he
finds but in gold parting he weighs two assay pie
of equal weight, of which he treats exactly
as silver assay, and the other gold assay
When this is done by weighing the two assay pie
ces against each other, the excess in the former,
which still retains the silver, becomes the report of
fine silver in the pound When the subject of trial
contains than moiety of alloy, it is denom-
mated metal for gold and silver, and the absolute
quantity of each is reported. The larger the guam
tty of metal used in these trials the less Will any
casual error in the process bear to the whole
otherwise the quantity is quite Indifferent for what
the assayer takes for his unit greatest weight
he divides proportionably to real Troy weights.