1. Gold, not being subject to intrinsic change by atmospheric action,
or by that of common chemical agents, is extensively used in gilding
various substances, either with the view of preserving them from
decay, or for the purpose of embellishment. To prepare the gold for
application in this manner is the business of the gold-beater.
2. The metal is first melted with some borax in a crucible, and formed
into an _ingot_ by pouring it into an iron mould. The mass is next
hammered a little on an anvil, to increase the cohesion of its parts,
and afterwards repeatedly passed between steel rollers, until it has
become a riband as thin as paper.
3. Two ounces and a half of this riband are cut into 150 pieces of
equal dimensions. These are hammered a little to make them smooth, and
then interlaid with pieces of fine vellum four inches square. The
whole, with twenty other pieces of vellum on each side, is inclosed in
two cases of parchment. The packet is then beaten on a marble anvil
with a hammer weighing sixteen pounds, until the gold has been spread
to near the size of the vellum leaves, it, in the mean time, being
often turned over.
4. The gold leaves are next divided into four equal squares, with a
steel knife on a leather cushion; and the 600 leaves thus produced,
are interlaid with a kind of leather or parchment made of the
intestines of the ox, and beaten with a hammer weighing twelve pounds,
until the leaves have been extended as before. They are again
quartered and interlaid, and beaten with a hammer weighing six or
eight pounds.
5. The gold having now been sufficiently extended, the packets are
taken apart, and the leaves cut to a proper and uniform size, by means
of a cane frame on a leather cushion. The leaves, as fast as they are
trimmed, are placed in a book, the paper of which has been covered
with red bole, to prevent the gold from sticking. Of the two ounces
and a half of gold thus treated, only about one ounce remains in
perfect leaves, which, altogether, amount to 2000 three inches and
three-eighths square. The books contain twenty-five leaves, so that
one ounce of gold makes eighty books.
6. Gold extended into leaves, is alloyed, in a greater or less degree,
with silver or copper, or both, because, in a pure state, it would be
too ductile. The newest skins will work the purest gold, and make the
thinnest leaf, because they are the smoothest. The alloy varies from
three to twenty-four grains to the ounce, but in general it is six, or
one part of alloy to eighty of gold.
7. A kind of leaf called _party gold_, is formed by the union of a
thin leaf of gold and a thicker one of silver. The two are laid
together, and afterwards heated and pressed, until they have cohered.
They are then beaten and otherwise treated, as in the process just
described. Silver, and likewise copper, are also beaten into leaves,
although they will by no means bear so great a reduction as gold.
Considerable quantities of copper leaf are brought from Holland, which
in commerce is known by the denomination of "Dutch leaf," or "Dutch
gold."
8. The ancient Romans were not ignorant of the process of
gold-beating, although they did not carry it so far as we do. Pliny
informs us that they sometimes made 750 leaves four fingers square,
from an ounce of gold. At Præneste was a statue of Fortune, gilt with
leaves of a certain thickness; hence those beaten to the same degree
of thickness were called _Prænestines_. Those of another and less
degree of thickness, were called _quæstoriales_, for a similar reason.
9. The Romans began to gild the interior of their houses immediately
after the destruction of Carthage. The wainscots of the Capitol were
first ornamented in this manner; and afterwards it became fashionable
to gild the walls and ceilings of private dwellings, as well as
articles of furniture.
10. _Gold wire._--The ductility of gold is more conspicuous in wire
than in leaves. The wire thus denominated, is in reality silver wire
covered with gold. It is formed by covering a silver rod with thick
leaves of gold, and then drawing it successively through conical holes
of different sizes, made in plates of steel. The wire may be reduced,
in this manner, to a degree of extreme fineness, the gold being drawn
out with the silver, and constituting for it a perfect coating.
11. Wire thus formed is often used in the manufacture of _gold
thread_. Before it is applied in this way, it is flattened between
rollers of polished steel, and then wound on yellow silk by machinery.
The coating of gold on the silver wire employed in this way, does not
exceed the millionth part of an inch in thickness.