s
been infused; but take care that the gold solution be sufficiently
liquid to flow freely in a pen. When the writing is dry, polish it
with a dry tooth.

_Another way._

Reduce gum ammoniac into powder, and dissolve it in gum arabic water,
to which a little garlic juice has been added. This water will not
dissolve the ammonia so as to form a transparent liquid; for the
result will be a milky liquor. With the liquor form your letters or
ornaments on paper or vellum, with a pen or fine camels'-hair brush;
then let them dry, and afterwards breathe on them some time, till they
become moist; then apply a few bits of leaf gold to the letters, which
you press down gently with cotton wool. When the whole is dry, brush
off the superfluous gold with a large camels'-hair brush, and, to make
it more brilliant, burnish with a dog's tooth.

_White Ink, for Writing on black Paper._

Having carefully washed some egg-shells, remove the internal skin, and
grind them on a piece of porphyry. Then put the powder into a small
vessel of pure water, and when it has settled at the bottom, draw off
the water, and dry the powder in the sun. This powder must be
preserved in a bottle; when you want to use it, put a small quantity
of gum ammoniac into distilled vinegar, and leave it to dissolve
during the night. Next morning the solution will appear exceedingly
white; and if you then strain it through a piece of linen cloth, and
add to it the powder of egg-shells, in sufficient quantity, you will
obtain a very white ink.

_To construct Paper Balloons._

Take several sheets of silk paper; cut them in the shape of a spindle;
or, to speak more familiarly, like the coverings of the sections of an
orange; join these pieces together, into one spherical or globular
body, and border the aperture with a ribbon, leaving the ends, that
you may suspend them from the following lamp.

Construct a small basket of very fine wire, if the balloon is small,
and suspend it from the aperture, so that the smoke from the flame of
a few leaves of paper, wrapped together, and dipped in oil, may heat
the inside of it. Before you light this paper, suspend the balloon in
such a manner, that it may, in a great measure, be exhausted of air,
and as soon as it has been dilated, let it go, together with the wire
basket, which will serve as ballast.

_Water-Gilding upon Silver._

Take copper-flakes, on which pour strong vinegar; add alum and salt in
equal quant