1leather, which sags about one hand's breadth; next, the
leather is folded
over and tied with a waxed string, and the dish catches the quicksilver
which is squeezed through it. As for the gold which remains in the leather,
it is placed in a scorifier and purified by being placed near glowing coals. Others
do not wash away the dirt with warm water, but with strong lye and vinegar,
for they pour these liquids into the pot, and also throw into it the quicksilver
mixed with the concentrates made by washing. Then they set the pot in a
warm place, and after twenty-four hours pour out the liquids with the dirt, and
separate the quicksilver from the gold in the manner which I have described.
Then they pour urine into a jar set in the ground, and in the jar place a
pot with holes in the bottom, and in the pot they place the gold; then the
lid is put on and cemented, and it is joined with the jar; they afterward heat
it till the pot glows red. After it has cooled, if there is copper in the gold
they melt it with lead in a cupel, that the copper may be separated from it;
but if there is silver in the gold they separate them by means of the aqua
which has the power of parting these two metals. There are some who,
when they separate gold from quicksilver, do not pour the amalgam into
a leather, but put it into a gourd-shaped earthen vessel, which they place
in the furnace and heat gradually over burning charcoal; next, with an iron
plate, they cover the opening of the operculum, which exudes vapour, and as
soon as it has ceased to exude, they smear it with lute and heat it for a short
time; then they remove the operculum from the pot, and wipe off the
quicksilver which adheres to it with a hare's foot, and preserve it for future
use. By the latter method, a greater quantity of quicksilver is lost, and by
the former method, a smaller quantity.
over and tied with a waxed string, and the dish catches the quicksilver
which is squeezed through it. As for the gold which remains in the leather,
it is placed in a scorifier and purified by being placed near glowing coals. Others
do not wash away the dirt with warm water, but with strong lye and vinegar,
for they pour these liquids into the pot, and also throw into it the quicksilver
mixed with the concentrates made by washing. Then they set the pot in a
warm place, and after twenty-four hours pour out the liquids with the dirt, and
separate the quicksilver from the gold in the manner which I have described.
Then they pour urine into a jar set in the ground, and in the jar place a
pot with holes in the bottom, and in the pot they place the gold; then the
lid is put on and cemented, and it is joined with the jar; they afterward heat
it till the pot glows red. After it has cooled, if there is copper in the gold
they melt it with lead in a cupel, that the copper may be separated from it;
but if there is silver in the gold they separate them by means of the aqua
which has the power of parting these two metals. There are some who,
when they separate gold from quicksilver, do not pour the amalgam into
a leather, but put it into a gourd-shaped earthen vessel, which they place
in the furnace and heat gradually over burning charcoal; next, with an iron
plate, they cover the opening of the operculum, which exudes vapour, and as
soon as it has ceased to exude, they smear it with lute and heat it for a short
time; then they remove the operculum from the pot, and wipe off the
quicksilver which adheres to it with a hare's foot, and preserve it for future
use. By the latter method, a greater quantity of quicksilver is lost, and by
the former method, a smaller quantity.
If an ore is rich in silver, as is rudis silver29,
frequently silver glance,
or rarely ruby silver, gray silver, black silver, brown silver, or yellow silver,
as soon as it is cleansed and heated, a centumpondíum (of the lesser weights) of
it is placed in an uncia of molten lead in a cupel, and is heated until the lead
exhales. But if the ore is of poor or moderate quality, it must first be dried,
then crushed, and then to a centumpondium (of the lesser weights) an uncia
of lead is added, and it is heated in the scorifier until it melts. If it is not
soon melted by the fire, it should be sprinkled with a little powder of the
first order of fluxes, and if then it does not melt, more is added little by little
until it melts and exudes its slag; that this result may be reached sooner,
the powder which has been sprinkled over it should be stirred in with an iron
rod. When the scorifier has been taken out of the assay furnace, the alloy
should be poured into a hole in a baked brick; and when it has cooled and been
cleansed of the slag, it should be placed in a cupel and heated until it exhales
all its lead; the weight of silver which remains in the cupel indicates what
proportion of silver is contained in the ore.
or rarely ruby silver, gray silver, black silver, brown silver, or yellow silver,
as soon as it is cleansed and heated, a centumpondíum (of the lesser weights) of
it is placed in an uncia of molten lead in a cupel, and is heated until the lead
exhales. But if the ore is of poor or moderate quality, it must first be dried,
then crushed, and then to a centumpondium (of the lesser weights) an uncia
of lead is added, and it is heated in the scorifier until it melts. If it is not
soon melted by the fire, it should be sprinkled with a little powder of the
first order of fluxes, and if then it does not melt, more is added little by little
until it melts and exudes its slag; that this result may be reached sooner,
the powder which has been sprinkled over it should be stirred in with an iron
rod. When the scorifier has been taken out of the assay furnace, the alloy
should be poured into a hole in a baked brick; and when it has cooled and been
cleansed of the slag, it should be placed in a cupel and heated until it exhales
all its lead; the weight of silver which remains in the cupel indicates what
proportion of silver is contained in the ore.
We assay copper ore without lead, for if it is melted with it, the copper
usually exhales and is lost. Therefore, a certain weight of such an ore
usually exhales and is lost. Therefore, a certain weight of such an ore