the sensitive coating is
given; particles of dust are thus effectually removed; the temperature
of the plate is also increased by the friction, and the required tint
more readily obtained.

SECOND OPERATION.--Applying the sensative coating.--The apparatus and
chemicals required, are an

Iodine box--see fig. 14 page 53.

Bromine box--similar to the iodine box but a trifle deeper.

Dry Iodine.

Bromine, or a compound of Bromine and Chloride of Iodine, or other
sensitive mixture.

Most of our best operators use the compound Bromine and Chloride of
Iodine. In the early days of the Daguerreotype, Iodine alone was used
in preparing the plate, and although it still plays a very important
part, other preparations, called accelerating liquids, quickstuff, &c.,
are used, and the discovery of which has alone ensured the application
of the Daguerreotype successfully to portrait taking--for when first
introduced among us it took from five to ten minutes to produce a
tolerable good view, while now but the fraction of a minute is required
to obtain an accurate likeness.

To iodize the plate perfectly it must be placed over the iodine vapor
immediately after buffing. Scatter from a sixteenth to the eighth of
an ounce of dry iodine over the bottom of your coating box, and
slightly cover it with cotton wool. The plate is then dropped into the
frame b, fig. 12, with its silvered surface downward, and thrust under
the lid h. The bright surface of the plate is soon coated with a film
of iodine of a fine yellow color; it is then removed and placed over
the accelerating solution. It is not absolutely necessary to perform
this operation in the dark, although a bright light should be avoided.
Not so the next part of the process, viz; giving the plate its extreme
sensitiveness, or coating with the accelerating liquids. In this great
caution should be used to prevent the slightest ray of light impringing
directly on the plate, and in examining the color reflected light
should always be used. A convenient method of examining the plate, is
to make a small hole in the partition of the closet in which you coat,
and cover it with a piece of tissue paper; by quickly turning the plate
so that the paper is reflected upon it the color is very distinctly
shown. Most of our operators are not so particular in this respect as
they should be.

ACCELERATING LIQUID.--Of these there are several kinds, which differ
both in composition and actio