the focus being adjusted by the screw I. The optical part of the instrument
consist of the small set of achromatic lenses already described.
When the portrait or view is deleniated on the ground glass
to the entire satisfaction of the operator, the brass cap L is
placed over the lens, and the entire body is removed away into
the dark, taking care not to disturb the position of the stand.
The body is now detached at the part H, and the prepared paper
or plate enclosed in the brass frame work introduced in its place;
the whole is again placed upon the pedestal, the brass cap L is removed,
by which the paper or plate is exposed to the full influence
of the light, after which the cap is again replaced.

Mr. Woodbridge, of this city, has constructed an instrument for taking full
length portraits on plates 10 by 13 inches, which is worthy of some notice.
It is a double camera, consisting of two boxes, placed in a frame,
one above the other, and so arranged as to slide easily up and down.
After the focus has been adjusted, on the object, in both cameras,
the plate is put into the upper box, in the manner already described,
until the superior portion of the figure is complete; it is then
placed in the second box and the lower extremities obtained.
The adjustment of the instrument is so complete that
[hipho_8.gif]
a perfect union of the parts is effected in the picture without the least
possible line of demarkation being visible. Fig. 8 gives a front view
of this instrument.

Fig. 9 represents Talbot's Calotype Camera,--a very beautiful instrument.

The copying camera box has an extra slide in the back end,
by which it may be considerably lengthened at pleasure.