The Artist's Assistant, In the Study and Practice of Mechanical Sciences: Calculated for the Improvement of Genius. Illustrated with Copper-Plates — Birmingham, [ca. 1785]

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THE ARTIST'S ASSISTANT. 281

fame inftant plunge your fneets of black iron; then
take out of the fire, and flop well the veffel. Let
your iron reft there and foak for twenty-four hours,
after which time take off your iron fheets ; fcore
them well with the very bran with which they have
been foaking, then rub them over a little with
grindftones. This being done, make them foak again
in a water wherein you fhall have diffolved fome am-
moniac fait, whence having taken them off, fet them
to drain, and rub them afterwards with rye-bran,
and your tin will be done.

Obferve that the veffel in which you la?p|rour fheets
to foak, malt be large enough to receive them in.
their full intended fize.

To compofe a metal of a gold colour:—Take re-
finer's copper fix ounces; melt it in a crucible;
add one ounce of calaminary ftone, half an ounce of
tutty, and one of terra merita, in powder ; give to this
a melting fire for five or fix hours running, and no
more; then take off the crucible from the fire. Put
tliis compofition in powder, and add to it two ounces
of common mercury, fix of fea-falt, exficcated, and a
fufficient quantity of water. Set the whole to boil
until there appears no more mercury ; then put the
matter into a crucible, and place it between two fires
of kindled coals, avoiding carefully the breathing of
the fumes : give this a melting fire, for two hours,
then wafh the compofition in water, till this runs off
quite clear ; fet this again in a crucible, and when
melted, pour it into an ingot. This will give you a
metal of the mod beautiful gold colour which can be
defired, and which you may make ufe of for plates,
buckles, fnuff-boxes, cane-heads, &c. But one can-
not recommend too much the avoiding of breathing
the fumes of this compofition, while it is making.

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