Fig. 1.
104
CAMEO - CAMERA OBSCURA
CAMERA OBSCURA,
an optical apparatus consisting of a
darkened chamber (for which its name is the Latin rendering)
at the top of which is placed a box or lantern containing a convex
lens and sloping mirror, or a prism combining the lens and
mirror, If we hold a common reading lens (a magnifying lens)
in front of a lamp or some other bright object and at some
distance from it, and if we hold a sheet of paper vertically at a
suitable distance behind the lens, we see depicted on the paper
an image of the lamp. This image is inverted and perverted.
[Fig. 1 appears here.]
If now we place a plane
mirror (e.g. a lady's hand
glass) behind the lens and
inclined at an angle of 45° to
the horizon so as to reflect
the rays of light vertically
downwards, we can produce
on a horizontal sheet of
paper an unperverted image
of the bright object (fig. 1), i.e. the image has the same appear-
ances the object and is not perverted as when the reflection of a
printed page is viewed in a mirror. This is the principle of the
Fig. 1.
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