s, will, I trust, be of some
service to all who adopt this pleasing art as a profession; and will,
with a due attention to the directions given in the practical working
of the Daguerreotype, Calotype, etc., ensure a corresponding measure of
success.

CHAP. V.

DAGUERREOTYPE APPARATUS.

The entire Daguerreotype process is comprised in seven distinct
operations; viz:

1.--Cleaning and polishing the plate.

2.--Applying the sensitive coating.

3--Submitting the plate to the action of light in the camera.

4.--Bringing out the picture; in other words rendering it visible.

5.--Fixing the image, or making it permanent--so that the light may no
longer act upon it.

6.--Gilding: or covering the picture with a thin film of gold--which
not only protects it, but greatly improves its distinctness and tone of
color.

7.--Coloring the picture.

For these various operations the following articles--which make up the
entire apparatus of a Daguerrean artist--must be procured

1.--THE CAMERA.--(Fig. 5.). The Camera Obscura of the Italian
philosophers, although highly appreciated, on account of the magical
character of the pictures it produced, remained little other than a
scientific toy, until the discovery of M. Daguerre. The value of this
instrument is now great, and the interest of the process which it so
essentially aids, universally admitted. A full description of it will
therefore be interesting.

[Illustration: Fig. 5 (hipho_5.gif)]

The camera is a dark box (a), having a tube with lenses (b) placed in
one end of it, through which the radiations from external objects pass,
and form a diminished picture upon the ground glass (g) placed at the
proper distance in the box to receive it; the cap c covering the lenses
at b until the plate is ready to receive the image of the object to be
copied.

Thus a (fig. 6.) representing the lens, and b the object desired to be
represented, the rays (c, c) proceeding from it fall upon the lens, and
are transmitted to a point, which varies with the curvature of the
glass, where an inverted image (d) of b is very accurately formed. At
this point, termed the focus, the sensitive photographic material is
placed for the purpose of obtaining the required picture.

[Illustration: Fig. 5 (hipho_6.gif)]

The great desideratum in a photographic camera is perfect lenses. They
should be achromatic, and the utmost transparency should be obtained;
and under the closest inspecti