ts prefer the white French plate glass--and many think,
very erroneously, that none is good unless it is thick--but the great
desideratum is clearness and freedom from blisters; even glass a little
tinged with green or yellow is to be preferred to the French plate when
cloudy or blistered and there is very little of it comes to this market
that is not so. It is to be hoped that some of our glass factories
will manage to manufacture an article expressly for daguerreotypes; and
I would recommend them to do so, for they would find it quite an item
of profit annually.

Before enclosing the picture in the case you should be careful to wipe
the glass perfectly clean, and blow from the picture any particles of
dust which may have fallen upon it. Then take strips of sticking
paper, about half or three quarters of an inch wide, and firmly and
neatly secure it to the glass, having first placed a "mat" between them
to prevent the plate being scratched by the glass.

TO MAKE SEALING PAPER.--Dissolve one ounce of gum arabic, and a quarter
of an ounce of gum tragicanth in a pint of water; then add a
teaspoonful of benzoin. Spread this evenly on one side of good stout
tissue paper; let it dry, and then cut it up in stripes, about half or
three quarters of an inch wide, for use. If it becomes too soft for
summer use, add gum arabic; if too hard and cracking, add benzoin or
gum tragicanth; if it gets too thick, add water.

COLORED DAGUERREOTYPES ON COPPER.--To effect this, take a polished
plate of copper and expose it to the vapor of iodine, or bromine, or
the two substances combined; or either of them in combination with
chlorine. This gives a sensitive coating to the surface of the plate,
which may then be submitted to the action of light in the camera.
After remaining a sufficient time in the camera, the plate is taken out
and exposed to the vapor of sulphuretted hydrogen. This vapor produces
various colors on the plate, according to the intensity with which the
light has acted on the different parts; consequently a colored
photographic picture is obtained. No further process is necessary as
exposure to light does not effect the picture.

By this process we have an advantage over the silvered plate, both in
economy, and in the production of the picture in colors.

INSTANTANEOUS PICTURES BY MEANS OF GALVANISM.--It will be seen by the
following valuable communication that galvanism can be successfully
applied in producing p