ade according to_ DR.
DIAMOND'S _formulary, which we find extremely soluble; and he can compare
it with that of his own production._

F. M. (Malta). _1st. We are informed by_ DR. DIAMOND _that however
beautiful the results obtained by others in the use of Canson's paper, in
his hands he has found no certainty in its action, and, for iodized paper
for negatives, far inferior to the best English papers. If the salts of
gold are to be used, deep tints are very readily obtained by the French
papers. The propriety of using gold is very questionable, not only as
affecting the after permanence of the picture, but from the strong
contrasts generally produced being very offensive to an artist's eye.
2ndly. Xyloidine may be iodized precisely the same as collodion, but no
advantage whatever is gained from its use. A collodion for the taking of
positives on glass should be differently made to one for negative pictures.
There should be less of the iodides contained in it, and it should be more
fluid. When this is the case, the image is never washed out by the hypo.,
and the delineation is equal in minuteness to any Daguerreotype on metal
plates, as has been shown by the specimens of the reduction of printing
exhibited by Mr. Rosling at the Society of Arts' Exhibition, where the
letters were reduced to 1-750th of an inch, or less than half the diameter
of a human hair. If the protonitrate of iron_ properly prepared _be used in
the development, the deposit assumes the beautiful appearance of dead white
silver, having none of the reflecting qualities of the metal plates._

C. E. F. (June 13th). _The spots in the specimen sent depend upon minute
substances in your collodion not receiving the action of the nitrate of
silver bath; and you will find this upon looking through a prepared plate
after it has been in the nitrate bath, and previously to its ever having
been in the camera. They may be iodide or iodate of silver, or small
crystals of nitrate of potash. If the former, add a little piece of iodide
of potassium, say ten grains to two ounces of collodion; or if the latter,
it would depend upon a defective washing of the gun cotton by which all the
soluble salts have not been removed: thus more care must be used. We would
recommend you to use an entirely new bath and stronger, four ounces of
hypo. to a pint: it is evident that your very nice specimens have been
spoiled by the stains of the bath. Allow us again to draw your attention to