that when the papers are ironed I sometimes find flaws and spots occur from
some carelessness in the ironing process.

If the albumenized paper is intended to be kept for any _long_ time before
use, the ironing may be useful as a protection against moisture, provided
the _iron be sufficiently hot_; but the temperature ought to be
considerable.

To render the paper sensitive, I use a hundred-grain solution of nitrate of
silver, of which forty-five minims will exactly cover the sheet of
seventeen inches by eleven inches, if laid on with the glass rod. A weaker
solution will do, but with the above splendid tints may be produced. As to
the ammonio-nitrate of silver, I have totally abandoned its use, and, after
many careful experiments, I am satisfied that its extra sensitiveness is a
delusion, while the rapid tendency of paper prepared with it to spoil is
increased tenfold.

The fixing, of course, modifies considerably the tone of the proof, but
almost any desired shade {397} may be attained by following the plan of MR.
F. M. LYTE, published in "N. & Q.," provided the negative is sufficiently
intense to admit of a considerable degree of over-printing.

It is a fact which appears to be entirely overlooked by many operators,
that the _intensity_ of the negative is the chief agent in conducing to
black tones in the positive proof; and it is almost impossible to produce
them if the negative is poor and weak: and the same observation applies to
a negative that has been _over_-exposed.

GEO. SHADBOLT.

_Cement for Glass Baths._--The best I have tried is Canada balsam. My baths
I have had in use five years, and have used them for exciting, developing
hypo. and cyanide, and are as good as when first used.

NOXID.

_New Process for Positive Proofs._--I have tried a method of preparing my
paper for positive proofs, which, as I have not seen it mentioned as
employed by others, and the results appear to me very satisfactory, I am
induced to communicate to you, and to accompany by some specimens, which
will enable you to judge of the amount of success.

I use a glass cylinder, with air-pump attached, such as that described by
MR. STEWART as employed by him for iodizing his paper. I put in this the
salt solution, and that I use is thus composed: 2 drachms of sugar of milk,
dissolved in 20 ounces of water, adding--

Chloride of barium 15 grs.
Chloride of sodium 15 grs.
Chloride of ammonium