the plate by the
lower right-hand corner, holding it in such a manner that the plyers
will form in a line with the upper left-hand corner; pour on, slowly,
the hyposulphite solution, slightly agitating the plate, until all the
coating is dissolved off; then rinse off with clean water, and if it is
not to be gilded, dry by holding the plate perpendicular with the
bottom left-hand corner lowest, and applying the blaze of the
spirit-lamp to the back, at the same time blowing gently downward on
the face of the plate.

The hyposulphite solution should be often filtered through a sponge,
and it will answer for a great number of washings. Yet it is observed
that the mercury collects in this solution in small globules; these
often come in contact with the plate, causing white spots, which spoil
the impression. They should be guarded against, and the solution
renewed. Again, in order to prevent streaks or scum on the surface of
the plate, it is necessary that the coating should be removed with a
good degree of uniformity. I find in practice that the hyposulphite of
soda in our market varies much as regards strength, and consequently
the rule to be adopted is to make a solution of sufficient strength to
remove the coating in about ten seconds. I am aware that it may be
said that this strong solution would have a tendency to injure the
impression by destroying in a measure the sharpness of outline. To
meet this, it need only to be said that the preventive is, to not let
the solution rest on the surface of the plate for a longer time than is
absolutely necessary, and then it should be drenched copiously with
water; hence a chemical action upon the image is prevented and the
general operation facilitated. This plan is adopted by our first
operators with the greatest success.

If the operator should allow the hyposulphite solution to run over the
plate unevenly, it is quite likely that white or blue streaks would
result. These it is impossible to remove without injury to the
impression. Some, in order to prevent this, breathe over the surface,
thus moistening it and putting it in a condition to receive the
solution with greater uniformity. The plate should be well washed with
water before gilding.

Gilding, or Fixing the Image.--The next process to be given is that for
fixing the image on the plate. This is done by precipitating a thin
film of gold over the surface and is productive of the most brilliant
effect when p