s the negative will come out almost as strong as if it had
been properly exposed and developed. Wash thoroughly and dry. If the
plate does not need much intensifying, leave it in the mercuric solution
just long enough for the surface to whiten.

Another formula for intensifying is one which can be used as soon as the
plates have been developed and fixed, and gives the required strength to
quite thin negatives. This is prepared in three solutions, and used in
the same way as the first formula given. No. 1, bichloride of mercury, 2
parts; water, 100 parts. No. 2, iodide of potassium, 3 parts; water, 33
parts. No. 3, sodic acetate, 4 parts; water, 33 parts.

Caution: Mark all bottles containing intensifying solutions "Poison," be
very careful in handling, and keep them locked up when not in use.
Bichloride of mercury (corrosive sublimate) is a violent poison, and a
grain or two of it taken internally may prove fatal. An antidote is the
whites of eggs beaten up with water and given promptly, repeatedly, and
abundantly. The albumen of the egg renders the salts of mercury
insoluble, and enables the stomach to throw off the poison instead of
absorbing it into the system.

MLLE. C. DE GRAMONT, Paris, France, asks "If an amateur can make a
non-halation plate, and how, and what is the best method of
sensitizing the salted paper described in No. 796?" Plates already
sensitized can be covered, rendered almost free from halation by
painting the back or glass side with a mixture of collodion and
rouge. In place of the rouge any dark red or brown pigment may be
used. The mixture dries quickly, and is easily wiped off the plate
before developing. Another mixture may be made of 1/2 oz.
gum-arabic, 1 drachm of glycerine, 1/2 oz. burnt sienna, and 5 oz.
water. Heat enough of the water to dissolve the gum-arabic, and
when cold mix all the ingredients together. Apply with a brush.
After exposure and before developing it should be wiped off the
plate with a cloth wet with benzine. In No. 803 will be found
further directions for preparing plain salted paper. The easiest
way to sensitize the paper is to cut it into 8 by 10 sheets, lay a
piece on a pane of glass, holding it from curling by two or three
letter-clips; or, if preferred, a smooth board can be used and the
paper fastened to the board with small thumb tacks. Apply lightly
and evenly, firs