which
one holds in the mouth, as much as necessary. Pulverize the dry
materials, mix the resin with them, and set it aside. Take liquid alum,
pour water upon it so that it becomes very watery and preserve it in a
clay vessel. Heat the stone in an earthen vessel and cool it off in the
alum. Heat the stone and put it in the above-named composition.
However, */ you desire that it should be greener then again mix pulverized verdigris with it.
The chemical nature of Scythian black is unknown.
77. Another {Recipe).
Grind scraped-off verdigris and soften in oil a day and a night. Boil the stones therein with a gentle flame as long as desired.
78. Preparation of Emerald.
Dissolve
alum with vinegar in an earthen vessel and set it aside. Take crystal
and leave it therein a day and a night. Then take it and coat it with
wax or clay. After that, cook it in oil. If, however, the stone is hard
hang it in honey. Then lift it out and put it in copper green a day and
a night. Take it out and cover it so that no evaporation occurs. After
that, smear it again with the materials until it becomes emerald.
79. Preparation of Emerald.
Mix:
copper green, 9 drachmas; celandine, 1 drachma; verdigris, 1 drachma;
indigo, 3 oboli; (and) resin. Coat the stones with this mixture.
80. The Dissolving of Comarum.
Take
and put lye from ashes upon comarum. Place it upon the fire a night and
a day and it will become dissolved. The lye from ashes is, however,
according to the following preparation. Place ashes in sufficient water
and put this in a pot. Make a cavity and put quicklime in the hole.
Pour in it the lye from the ashes and it will flow pure through the
palm flower wrapping. A pply this material for dissolving.
The substance called "comarum" was used as a mordant in coloring stones and cloth. Its exact nature is not known.
81. Another (Recipe).
Several
have also undertaken the dissolving with this, namely "capnelaion,"
which is a very dear substance; others again with the sap of balsam
trees.
82. Another (Recipe).
The
dissolving of comarum. Put in a pot about two pints of spring water.
When this has been boiled once, put in the pot a third of gum
tragacanlh and a third of cleaned and washed comarum which you have
finely pulverized. However, when this has boiled six times take it away
from the fire—but boil with a gentle fire. Place it again upon
the ground, let it cool off for several days and use it thus. The
solution of comarum is also useful as a preliminary coating for every
stone.
83. Preparation of Emerald.
Mix and put together in a small far •/, o drachma of copper green, 1/i a drachma of A rmenian blue, l/> a.
cup of the urine of an uncorrupted youth, and two-thirds of the fluid
of a steer's gall. Put entire stones therein, indeed (about) 24 pieces,
so that they weigh about 'A an obolus. Lay the cover upon the
pot, lute the cover all around with clay, and boil it with a gentle
fire for six hours, at which olive wood is to be burned. But if this
sign appears, namely, that the cover becomes green, then heat no more,
but cool off and take the stones out. Thus you will find that they have
become emeralds. The stones are of crystal. All crystal, however,
changes its color by boiling.
