ater. First wash the plate with clear water; then immerse it
in the saline solution, when it should be agitated, and the coating
will soon disappear. Another process with a salt solution of half the
strength of the above is very interesting and effectual. The plate
having been dipped into cold water, is placed in a solution of common
salt, of moderate strength; it lies without being acted upon at all;
but if it be now touched on one corner with a piece of zinc, which has
been scraped bright, the yellow coat of iodine moves off like a wave
and disappears. It is a very pretty process. The zinc and silver
forming together a voltaic pair, with the salt water intervening,
oxidation of the zinc takes place, and the silver surface commences to
evolve hydrogen gas; while this is in a nascent condition it decomposes
the film of iodide of silver, giving rise to the production of
hydriodic acid, which is very soluble in water, and hence instantly
removed.

This process, therefore, differs from that with hyposulphite. The
latter acts by dissolving the iodide of silver, the former by
decomposing it. It is necessary not to leave the zinc in contact too
long, or it deposits stains, and in large plates the contact should be
made at the four corners successively, to avoid this accident.

Gilding Solution.--To one pint of pure rain or distilled water add
fifteen grains of pure chloride of gold, and to another pint add sixty
grains of hyposulphite of soda. When dissolved, pour the gold solution
into the hyposulphite by small quantities, shaking well after each
addition. The soda solution must not be poured into the gold, as the
gold would be immediately decomposed, and the solution turn black, and
be unfit for use.

Some operators add muriate of potash and other substances, but these do
not possess any advantage except in cases where it is necessary to
bleach the solarized portions of the impression, and when such is the
case, chloride of sodium (common salt) is probably as effective and is
the most convenient. Add about a teaspoonful to two ounces of the
gilding.

Solution, for Increasing the Brilliancy of the Daguerreotype.--This
solution will have the effect to thoroughly cleanse the surface of the
gilded plate and excite a powerful influence on the general character
of the impression. To a solution of three ounces of water, in which is
dissolved a quarter of an ounce of cyanide of potassium, add one
teaspoonful of a so