-

Albumen 8 oz.
Water 12 oz.
Muriate ammon. 60 grs.
Common salt 60 grs.

And this, I find, gives a sufficient gloss to the paper; but that of course
is a matter of taste.

I have not either found it essential to allow the paper to remain on the
solution three minutes or longer, as recommended by DR. DIAMOND. With
Canson paper, either negative or positive, a minute and a half has been
sufficient. I have used two dishes, and as soon as a sheet was removed,
drained, and replaced, I have taken the sheet from the other dish. In this
way I found that each sheet lay on the solution about one and a half
minutes, and with the assistance of a person to hang and dry them (which I
have done before a fire), I have prepared from forty to forty-five sheets
in an hour, requiring of course to be ironed afterwards.

I have tried a solution of nitrate of silver of thirty grains to one ounce
of distilled water, to excite this paper, and it appears to answer just as
well as forty grains. I send you two small collodion views, takes by me and
printed on albumenized paper prepared as mentioned, and excited with a
30-grain solution of nitrate of silver.

Is there any certain way of telling the right side of Canson paper,
negative and positive? On the positive paper on one side, when held in a
particular position towards the light, shaded bars may be observed; and on
this side, when looked _through_, the name reads right. Is this the right
or the wrong side?

C. E. F.

Since I wrote to you last, I have tried a solution of twelve grains only of
nitrate of silver to the ounce of distilled water, for the paper
albumenized, as mentioned in my letter of the 13th of February, and have
found it to answer perfectly. The paper I used was _thin_ Canson, floated
for one minute exactly on the solution; but I have no doubt the thick
Canson will succeed just as well; and here I may observe that I have never
found any advantage in allowing the paper to rest on the solution for three
or four minutes, as generally recommended, but the contrary, as the paper,
without being in the least more sensitive, becomes much sooner discoloured
by keeping. My practice has been to float the thin Canson about half a
minute, and the thick Canson not more than a minute.

C. E. F.

_Mr. Crookes on restoring old Collodion._--I am happy to explain to your
correspondent what I consider to be the _rationale_ of the proce