The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1867-02-11
CITY INTELLIGENCE.



TFoR ADDITIONAL LOCAL ITEMS SEE THIRD PAaE.l
THE MINT-THE ANNUAL TRIAL BY
ASSAY OF THE GOLD AND SILVER COINAGE
low 1T is DONE AND THE, PRINCIPLES OF THE
OPERAT1oN.-In the month of February of each
year there Is commission appointed by the
Llon with the officers Of the Mint and the Com
mlttee on Coinage, Weights, and Measures of
Lne house OF Representatives, make a thorough
trial Of the gold and silver coinage of the differ
enI Mints in the country, with view to de-
termine whether they come up to the govern
The following gentlemen, appointed as Com
mlssioners by the President-
Professor Joseph Henry, Washington; Pro-
lessor John Torrey, New York; Hon. Samuel b.
Ruggles, New York; Professor ]. H. Alexander,
baltimore; Professor George j. Brush, New
Haven; Professor Robert f. Rogers, Philadel-
phla; Professor Charles NJ. .Wetherell. Bethlehem,
Pa; William S. Appleton Boston, Mass; Pro-
1essor Stephen Alexander, Princeton, N. j.; and
the House Committee, consisting OF Hon, John
A. Kasson, of Iowa tchairmanG Hon. Charles
II. Winfield, of N. Y; Hon. Thomas Williams
of Pa; Hon. Hezekiah 5. Bundy, of Ohio; and
Hon. Henry l.. Dawes, Of Mass, assembled at
the Mint at 10 o'clock this morning. After Or
ganizing in conjunction with the officers of the
Mint, and the reading Of the act of Congress in
relation to the duties of the commission, they
proceeded to the business of the meeting
out of the different pieces of gold and silver
struck off at the different places of coinage, a
certain number of each denomination are laid
aside for this annual assay, and are called the
reserved coins" These are placed IN packages
/. Gold coins from the Mint at Philadelphia.
q Silver coins from the same
B. Gold coins from the Branch Mint at New
Orleans.
q. silver coins from the same
8. Gold coins from the Branch Mint at San
G. silver coins from the same
7. Gold coins from the Branch Mint at Char
s. Gold coins from the Branch Mint at Dah-
lonega.
These coins were weighed, and the number
in each parcel: was recorded upon the Secre-
tary's minutes.
THE OPERATION OF AssAYING GOLD.
After the weighing of the several parcels of
gold and silver coinage, the Commission pro-
ceeded to assay the coin with reference to its
deviation, II any, from the standard hneness
The general principles of this operation is as
follows:-
According to law the standard gold of the
United States is so constituted that in 1000 parts
of weight 800 shall be of pure gold and 100 OF an
alloy Of copper and silver. The process Of assay
ing requires that the silver and copper shall be
entirely separa ed from the gold; and to effect
this two operations are necessary.
The first is to remove the copper. This is
done by a method called cttpeiLdtiOn which is
conducted in an assay furnace in cupeI
made of calcined bones. By adding lead and
copper is separated entirely. TO separate the
silver from the gold, it is necessary to add more
silver until there are three parts of silver to
one of gold. Then the alloy OF gold and silver
thus formed is rolled ont into thin ribbons and
boiled in nitric acid until the silver is entirely
eaten out.
THE TEST ASSAY.
To test the accuracy of the above process, the
following method is emplOyed:-
A roll of gold, of absolute purity, which has
been Kept under the seal of the Chairman of
the Assay Commissioners, is opened in their
presence and from it is taken the weight of
300 parts. To this is added rs of copper and 25
of silver; so as to form, with the gold, q weight
Of 1000 parts of the exact legal standard.
This is passed through the same process of
assay as the other gOld and at the same time.
After the assay is finished, it is evident that the
pure gold remaining ought 10 weigh exactly
800. If, however, from any cause, 1t be found to
differ from this weight and, therefore, to require
correction, il Is assumed that the same correc-
ton must be made in the other assays and this
is done accordingly
ASSAY OF SILVER COINAGE.
The standard silver of the United States is so
constituted that, of 1000 parts by weight, $40
shall be Jpure silver and 100 of copper.
In the process called the humid assay, the
silver coin is first granulated, and ihen dis
solved in nitric acid, and to the solution COM
mon salt is added, which precipitates the silver
in the form of an insoluble chloride. In the
testing of silver coinage too high degree of
fnenesS is sometimes exhibited, owing TO the
fact that, at certain grades of alloy, and espe-
ingots draw the better metal to the interior, and
the worst towards the exterior and the edges.
Hence the tneness of pieces cut of the central
part of the ingot is higher than the average fine
dess OF the ingot.
After the Commissioners have made
thorough examination of the different coinages
they will transmit their report and Kive in a
tabular form, the different degrees Of flneness
of the several coins, and how much they are
above and below the standard The gold coins
are allowed deviation of 2-l0OOths above and
below the standard, and a like deviation o
3-lOO0ds above and below is allowed for the silver
coinage.