GOLD, 
tli an might at first be expected. The at- 
tentive assayer not only compares the co- 
lour of the stroke made upon the touch- 
stone by the metal under examination with 
that produced by his needle, but will like- 
wise attend to the sensation of roughness, 
dryness, smoothness, or greasiness, which 
the texture of the nibbed metal excites 
when abraded by the stone. When two 
strokes, perfectly alike in colour, are made 
upon the stone, he may then wet them 
with aqua-fortis, which will affect them 
very differently if they be not similar com- 
positions ; or the stone itself may be made 
red hot by the fire, or by the blowpipe, 
if thin black pottery be used, in which 
case the phenomena of oxydation will differ 
according to the nature and quantity of 
the alloy. 
Gold ores may be assayed in the moist 
way by pounding them very fine, weighing 
a determinate portion, and attempting their 
solution in nitric acid, which will dissolve 
the matrix if it consist of calcareous earth ; 
or if it be sulphate of lime the powder may 
be digested in aqua-regia as long as any 
metallic substance is taken up ; after which 
the gold may be precipitated by an addition 
of sulphate of iron, which will cause it to 
fall down in the metallic state. 
The principal use of gold is as the medium 
of exchange in poin, for which it has been 
chosen to occupy the first place, on account 
of its scarcity, its great weight, and its not 
being subject to tarnish. The gold coins of 
Great Britain contain eleven parts of gold 
and one of copper. See Coin. 
Gold is likewise used in gilding. See 
Gilding. 
The other uses of gold, in laces, &c. are 
sufficiently known. 
Gold beating. See Gold. 
Gold wire, a cylindrical ingot of silver, 
superficially gilt, or covered with gold at the 
fire, and afterwards drawn successively 
through a great number of little round holes 
of a wire-drawing iron, each less than the 
other, till it be sometimes no bigger than 
a hair of the head. It may be observed, 
that before the wire be reduced to this ex- 
cessive fineness, it is drawn through above 
an hundred and forty different holes, and 
that each time they draw it, it is rubbed 
afresh over with new wax, both to facilitate 
its passage, and to prevent the silver’s ap- 
pearing through it. 
Gold wire flatted, is the former wire 
flatted between two rollers of polished 
steel, to fit it to be spun on a stick, or to 
be used flat, as it is without spinning, in 
certain stuffs, laces, embroideries, &c. 
Gold thread, or spun gold, is a flatted 
gold, wrapped or laid over a thread of silk, 
by twisting it with a wheel and iron bob- 
bins. 
Manner of forming gold wire and gold 
thread, both round and flat. First, an in- 
got of silver, of 24 pounds, is forged into a 
cylinder of about an inch in diameter: then 
it is drawn through eight or ten holes of a 
large, coarse, wire-drawing iron, both to 
finish the roundness, and to reduce it to about 
three-fourths of its former diameter. This 
done they file it very carefully all over to 
take off any filth remaining on the forge ; 
then they cut it in the middle ; and thus 
make two equal ingots thereof, each about 
26 inches long, which they draw through 
several new holes, to take off any inequalities 
the file may have left, and to render it as 
smooth and equable as possible. 
The ingot thus far prepared, they heat it 
in & charcoal firej then taking some gold 
leaves, each about four inches square, and 
weighing twelve grains, they join four, eight, 
twelve, or sixteen of these, as the wire is 
intended to be more or less gilt, and when 
they are so joined as only to form a single 
leaf, they rub the ingots reeking hot with a 
burnisher. These leaves being thus pre- 
pared, they apply over the whole surface of 
the ingot, to the number of six, over each 
other, burnishing or rubbing them well 
down. When gilt, the ingots are laid anew 
in a coal fire ; and when raised to a certain 
degree of heat, they go over them a second 
time, both to solder the gold more perfectly 
and to finish the polishing. The gilding 
finished, it remains to draw the ingpt into 
wire. 
In order to this, they pass it through 20 
holes of a moderate drawing-iron, by which 
it is brought to the thickness of the tag of a 
lace : from this time the ingot loses its name, 
and commences gold wire. Twenty holes 
more of a lesser iron leaves it small enough 
for the least iron ; the finest holes of which 
last scarcely exceeding the hair of the head, 
finish the work. 
To dispose the wire to be spun on silk, 
they pass it between two rollers of a little 
mill : these rollers are of nicely polished 
steel, and about three inches in diameter. 
They are set very close to each other, and 
turned by means of a handle fastened to 
one of them, which gives motion to tire 
other. The gold wire in passing between 
the two, is rendered quite flat, but without 
