Thibodaux minerva. [volume] (Thibodaux, La.) 18??-1858, 1854-01-28
A PERFECT INsrRUMENr-If it be the

| A PERFECT INsTRUMENT.-lf it be the
perfection of machine or instrument to be
unfaiing and invariable, not liable to get
out Of repair nor to wear out in hundred
years, of great utility and at the same time
so simple as to be understood and used by a
child, just such an instrument has DR.. Gid
con B. Smith, of Baltimore, invented as an
infalIible and instantaneous detector OF
counterfeit gold coins, from one dollar TO
twenty. The instrument is the size OF
large snuff box, and it will pass genuine
coins and reject false ones just as fast as
they can be counted. The inventor gives
the following description Of it:
This counterfeit gold coin detector is
constructed upon the we'll known scientific
principle, the specific gravity of metals.
Scientific men know very well what this
specific gravity means but that all may
comprehend it, and thereby be enabled to
Judge of the value of this instrument, let US
suppose each of the different metals that
can be used in counterfeiting gold coin to
be melted and cast into pint measures, and
then ascertain what a pint of each metal
will weigh. This will make the compare
tive specific gravity of metals plain 10 every
body We shall thus find that pint of
anthony weighs 6 pounds II ounces; a
pint of zinc pounds; pint Of tin pounds
S ounces; pint Of iron pounds IL ounces !;
pint of copper 8 pounds ID ounces pint
of nickel pounds 4 ounces; pint of cad
MUM pounds IL ounces; pint of uranim
pounds; pint of bismuth pounds IA
ounces; pint of silver 10 pounds ounces !;
pint Of palladium II pounds; pint of lead
II pounds 5 ounces; pint Of quicksilver 10
pounds ounces; pint of gold 10 pounds 4
ounces. All the alloys or mixed metals,
such as brass, bronze, pewter, Brtanic metal,
German silver, &c. vary as to their specific
gravilies according 10 the various propor-
tons Of their ingredients; but as they are all
composed Of some two or more Of the above
metals, Except gold) they cannot weigh as
much as the heaviest one Of their ingre-
dients, nor can any one of them weigh as
much as lead, nor can they be made as
heavy as gold by more than one-,hird.
Platinum is heavier than gold, but cannot
be used in counterfeiting on account OF its
value, scarcity and unmanageable qualities,
beng infusible by any ordinary means.
From the above it will be seen that piece
of money that will weigh 26 grains, if made
Of any other metal than gold, must necessa-
rily be at least one-third larger than gold
dollar; or, if made exactly the size Of a gold
dollar, it must of necessity be one-third
lighter. Now, this instrument will instant
y detect either Of these differences. Any
piece of money that will pass by its own
weight and size into it must necessarily be
gold. If it be too large it cannot be forced
into the instrument: fit be too light, it will
remain suspended on the balance; if il be
genuine gold coin, it will instantly pass
through the balance, and fall into the recep::
tacle below The detector is adapted to all
the gold coins now issued by the United
States Mint or that are in circulation, and
to the English sovereign, and to all gold
coins of other countries Of like value. The
coins can be passed through the instrument
as fast ashley can be counted singly. The
instrument is simple in construction, not
liable to get out of order, and will last a
lifetime. r. i