DOI Page / Citation link:
https://doi.org/10.11588/diglit.19574#0105
C H A 9l
To make a Chalcedony in glafs. There are three different
ways to prepare an artificial Chalcedony, which will make three
different fpecies of it, all of them very fair, but whofe beauty
alfo may be augmented by the number ©f ingredients they are
compofed of; and which caufe thofe diverfities of colours, which
that ftone ought to have.
Among the reft of the ingredients employed for this purpofe,
there are fome that give no colour to glafs, as tartar, foot, ar-
moniac, and mercury.
Thofe that are of an uncommon nature, as lead, foot, tartar,
and the azure ftone, often hinder the union of the ingredients,
by reafon of the feparation which may happen by the cooling the
metal, which does not happen to thofe who know how to ob-
ferve the degree of heat, wherein the principal knowledge of this
art confifts.
To make the firji fort of Chalcedony. Put a pound of
aqua-fortis prepared into a glafs body with a long ftick, and two
ounces of filver in fmall and thin plates, or granulated ; put the
body in an afh furnace, over a foft fire, or in warm water, and
the filver will be prefently diffolved.
At the fame time, take another body and diffolve in it three
ounces of quickfilver, in twelve ounces of the fame aqua-fortis ;
then mix both the folutions together into a larger body, which
fet into the fame bath of warm water, of afh furnace ; then add
to it three ounces of fal armoniac, which diffolve over a gentle
fire ; then add to it half an ounce of zaffer, and a quarter of an
ounce of manganefe prepared, by little and little, with as much
feretto of Spain, alfo by little and little, for fear the matter, com-
ing to fwell too much, fhould break the veffel.
Add to all thefe ingredients half an ounce of crocus martis
calcined with fulphur, as much fcales of copper three times cal-
cined, which ought to boil like manganefe; as much blue lake
(fuch as is ufed by painters) and the fame quantity of red lead,
the whole reduced to powder.
In putting in thefe powders, you muff, gently ftir the glafs
body, that they may the better incorporate with the aqua-fortis,
but be fure to take care that there be not too much heat; then
ffop the matrafs, or glafs body, very well, ftirring it well every
day, for ten days, that the powders may well incorporate, and
that they may always appear as feparated from the water.
Set the large glafs body into a fand furnace, in a temperate
heat, or rather empty it into a glafs cucurbit, after you have
well luted it at the bottom, and fet it over the fame fire, fo that
the aqua-fortis may evaporate in twenty-four hours; and at the
bottom of the veffel you will have a yellow powder, which keep
fafely in glaffes for ufe.
When
To make a Chalcedony in glafs. There are three different
ways to prepare an artificial Chalcedony, which will make three
different fpecies of it, all of them very fair, but whofe beauty
alfo may be augmented by the number ©f ingredients they are
compofed of; and which caufe thofe diverfities of colours, which
that ftone ought to have.
Among the reft of the ingredients employed for this purpofe,
there are fome that give no colour to glafs, as tartar, foot, ar-
moniac, and mercury.
Thofe that are of an uncommon nature, as lead, foot, tartar,
and the azure ftone, often hinder the union of the ingredients,
by reafon of the feparation which may happen by the cooling the
metal, which does not happen to thofe who know how to ob-
ferve the degree of heat, wherein the principal knowledge of this
art confifts.
To make the firji fort of Chalcedony. Put a pound of
aqua-fortis prepared into a glafs body with a long ftick, and two
ounces of filver in fmall and thin plates, or granulated ; put the
body in an afh furnace, over a foft fire, or in warm water, and
the filver will be prefently diffolved.
At the fame time, take another body and diffolve in it three
ounces of quickfilver, in twelve ounces of the fame aqua-fortis ;
then mix both the folutions together into a larger body, which
fet into the fame bath of warm water, of afh furnace ; then add
to it three ounces of fal armoniac, which diffolve over a gentle
fire ; then add to it half an ounce of zaffer, and a quarter of an
ounce of manganefe prepared, by little and little, with as much
feretto of Spain, alfo by little and little, for fear the matter, com-
ing to fwell too much, fhould break the veffel.
Add to all thefe ingredients half an ounce of crocus martis
calcined with fulphur, as much fcales of copper three times cal-
cined, which ought to boil like manganefe; as much blue lake
(fuch as is ufed by painters) and the fame quantity of red lead,
the whole reduced to powder.
In putting in thefe powders, you muff, gently ftir the glafs
body, that they may the better incorporate with the aqua-fortis,
but be fure to take care that there be not too much heat; then
ffop the matrafs, or glafs body, very well, ftirring it well every
day, for ten days, that the powders may well incorporate, and
that they may always appear as feparated from the water.
Set the large glafs body into a fand furnace, in a temperate
heat, or rather empty it into a glafs cucurbit, after you have
well luted it at the bottom, and fet it over the fame fire, fo that
the aqua-fortis may evaporate in twenty-four hours; and at the
bottom of the veffel you will have a yellow powder, which keep
fafely in glaffes for ufe.
When