a
towel, or press it between bibulous paper, by which operation the salt
is uniformly dispersed through its substance. Then brush over it, on
one side only, a solution of nitrate of silver. The strength of this
solution must vary according to the color and sensitiveness required.
Mr. Talbot recommends about fifty grains of the salt to an ounce of
distilled water. Some advise twenty grains only, while others say
eighty grains to the ounce. When dried in a dark room, the paper is
fit for use. To render this paper still more sensitive, it must again
be washed with salt and water, and afterwards with the same solution of
nitrate of silver, drying it between times. This paper, if carefully
made, is very useful for all ordinary photographic purposes. For
example, nothing can be more perfect than the images it gives of leaves
and flowers, especially with a summer's sun; the light, passing through
the leaves, delineates every ramification of their fibres. In
conducting this operation, however, it will be found that the results
are sometimes more and sometimes less satisfactory, in consequence of
small and accidental variations in the proportions employed. It
happens sometimes that the chloride of silver formed on the surface of
the paper is disposed to blacken of itself, without any exposure to
light. This shows that the attempt to give it sensibility has been
carried too far. The object is, to approach as nearly to this
condition as possible without reaching it; so that the preparation may
be in a state ready to yield to the slightest extraneous force, such as
the feeblest effect of light.

Cooper's Method.--Soak the paper in a boiling hot solution of chlorate
of potash (the strength matters not) for a few minutes; then take it
out, dry it, and wet it with a brush, on one side only, dipped in a
solution of nitrate of silver, sixty grains to an ounce of distilled
water, or, if not required to be so sensitive, thirty grains to the
ounce will do. This paper possesses a great advantage over any other,
for the image can be fixed by mere washing. It is, however, very apt
to become discolored even in the washing, or shortly afterwards, and
is, besides, not so sensitive, nor does it become so dark as that made
according to Mr. Talbot's method.

Daguerre's Method.--Immerse the paper in hydrochloric (or as it is more
commonly called, muriatic) ether, which has been kept sufficiently long
to become acid; the paper is then