n of an air-tight connection. This is
obviated entirely by employing a cement which fastens alike well to the
rubber and to the metal or wood. Such cement is prepared by a solution
of Shellac in Ammonia. This is best made by soaking pulverized Gum
Shellac in ten times its weight of strong Ammonia, when a slimy mass is
obtained, which in three or four weeks will become liquid without the
use of hot water. This softens the rubber and becomes, after
volatilization of the Ammonia, hard and impermeable to gases and
fluids.

TO TRANSFER PRINTED MATTER AND PRINT FROM IT AGAIN.--Take your picture
or print and soak it for a short time in a weak solution of Caustic
Potash, then remove it carefully, and let it dry on a sheet of clean
paper. Then take a piece of copper, zinc, or steel, which has
previously been well cleaned, and dip it into hot white wax. Let the
first coat set, then dip again. Having got the plate thoroughly coated
and set, lay the matter to be transferred on the plate, and rub it
gently all over on the back; now raise it up, and it will be
transferred on to the wax on the plate. Now take needles of a different
thickness, and scrawl all over the wax, following the lines of the
engraving. Having got the picture all traced out, pour upon it some
weak acid if you use zinc, which is too soft to print many from,
therefore it is better to use copper or steel. If you use copper, make
the following solution to pour over it: Verdigris four parts, Salt four
parts, Sal Ammoniac four parts, Alum one part, Water sixteen parts,
Sour Vinegar twelve parts. Dissolve by heat. For steel, use
Pyroligneous Acid five parts, Alcohol one part, Nitric Acid one part.
Mix the first two, then add the Nitric Acid. Pouring the preparations
over the plates where the traces of the pictures are, it will eat into
the metal plate without affecting the wax. Let it stand till it has
eaten a sufficient depth, then wash the plate with cold water, dry it
and place it near the fire till all the wax is melted off. You can now
print as many as you please from the plate by rubbing on it printer's
ink, so as to fill all the fine spaces; which, when done, wipe it over
smoothly with clean cloths to remove the superfluous ink which is on
the face of the plate. Now take damp paper or cardboard, and press it
on the plate, either with a copying press or the hand, and you get a
fine impression, or as many as you want by repeating the inking
process. I would recomm