n--some acting very quickly, others giving
a finer tone to the picture although they are not so expeditious in
there operations; or in other words, not so sensitive to the action of
light. These are adopted by Daguerreotypists according to their tastes
and prejudices. They are all applied in the same way as the coating of
iodine. The following are the best.

Bromine water--This solution is much used in France, and, I shall
therefore give its preparation, and the method of using it, in the
words of M. Figeau. "Put into a bottle of pure water, a large excess
of bromine; shake the mixture well, and before using it, let all the
bromine be taken up. An ascertained quantity of this saturated water
is then diluted in a given quantity of distilled water, which gives a
solution of bromine that is always identical." M. Figeau recommends one
part of the saturated solution to thirty parts its bulk of water; but
M. Lesebour finds it more manageable if diluted with forty times. In
case pure distilled, or rain water cannot be procured, a few drops of
nitric acid--say six to the quart--should be added to the common water.

Put into the bromine box a given quantity of this solution, sufficient
to well cover the bottom; the plate, having been iodized to a deep
yellow, is placed over it; the time the plate should be exposed must be
ascertained by making a few trials; it averages from twelve to forty
seconds. When once ascertained, it is the same for any number of
plates, as the solution, which of course would become weaker and
weaker, is changed after every operation, the same quantity being
always put into the pot.

Chloride of Iodine.--This is prepared by introducing chlorine gass into
a glass vessel containing iodine; the iodine is liquified, and the
above named compound is the result. Operators need not, however, be at
the trouble and expense of preparing it, as it can be obtained
perfectly pure of Mr. Anthony, 205 Broadway, N. Y., as also all of the
chemicals herein enumerated. The compound is diluted with distilled
water, and the plate submitted to its action till it is of a rose
color. Chloride of iodine alone, is seldom if ever used now by
American operators, as it does not sufficiently come up to their
locomotive principle of progression. The next is also eschewed by the
majority, although many of our best artists use no other, on account of
the very fine tone it gives to pictures.

Bromide of Iodine.--This is a co