depicted it as swung
from a pivot in the brass, and in Fig. 3 as hung from a screw in
the wood of the front board; either construction will be
effective.

Lastly, it is necessary to provide a finder for this camera in
order to know what picture you are taking. Make a little frame of
wire, the size of the plate you are using, and mount it upright
(see Fig. 5) on top of the camera as close to the end where the
pin hole is as you can. At the other end, in the center, erect a
little pole of wire half the height of the plate. If now you look
along the top of this little pole, through the wire frame and see
that the top of the little pole appears in the center of the
frame, everything that you see beyond will be

[Illustration: Pin Hole and Shutter Construction]

taken on the plate, as will be made plain by looking at the dotted
lines in Fig. 5, which represents the outer limits of your vision
when confined within the little frame.

[Illustration: Explanation of Action of Pin Hole]

When you want to use this camera, take it into an absolutely dark
room

[Illustration: Constructing a Finder for Camera]

and insert a plate (which you can buy at any supply store for
photographers) in the end where the slides of wood are, and
between them and the back of the box. Close the lid and secure it
with a couple of rubber bands. See that the little shutter covers
the hole. Now take the camera to where you wish to take a
photograph, and rest it securely on some solid surface. The
exposure will be, in bright sunlight and supposing that your
camera is 10 in. long, about six to eight seconds. This exposure
is made by lifting the little brass shutter until the hole is
uncovered, keeping it up the required time, and then letting it
drop back into place. It is important that the camera be held
rigid during the exposure, and that it does not move and is not
jarred--otherwise the picture will be blurred. Remove the plate in
the dark room and pack it carefully in a pasteboard box and
several wrappings of paper to protect it absolutely from the
light. It is now ready to be carried to some one who knows how to
do developing and printing.

To explain the action of the pin hole I would direct attention to
Fig. 2. Here F represents the front of the camera, D the pinhole,
AA the plate and the letters RR, rays from a lighted candle. These
rays of course, radiate in all directions, an infinite multitude
of them. Similar rays radiate from eve