The Chadburn attachment to the oxyhydrogen microscope serves its purpose
excellently, but a singular means of exhibiting _opaque_ bodies, of any
description whatever, has been contrived by the Optician Kruss, of
Hamburg.
[Illustration: Fig. 141.]
A tin box, 4 4 4 4, a foot cube, or a little less high than broad and
long, is divided by a tin partition, M, into two compartments, A and B,
dark chambers, in fact.
In the room, B, a lamp, C, has a concave reflector, D, which
concentrates the light upon a condensing lens (commonly called a bull’s
eye), E. This light is directed upon the place F, where a door is made
with a convenient slit for the insertion of prints, cartes de visite, or
other photographs, lace, gems, jewels (the most intricate patterns
afford pictures of great beauty, and the scintillations of colour from
diamonds and other stones are perfectly bewitching), &c. Or the door can
be opened, and one’s hand, eye, ear, or any other object held to the
light, is likewise projected on the screen through the tube H H. This
tube is solidly inserted in the end of the room A, diametrically
opposite an imaginary circle drawn on the side or end of the door F. A
second tube slides freely in and out, containing two lenses, as in
ordinary magic lanterns.
A screen is constructed of an upright frame, on which is smoothly
stretched common white tissue-paper, or the same oiled, or linen or silk
made transparent.
An object being placed in the door F, the light being turned on and the
focus being properly obtained, the picture projected on the screen will
be seen by persons on its other side greatly magnified.
Where the oxyhydrogen light cannot be used the lamp should furnish the
next best light. Pure sperm oil, in which crushed camphor, an ounce to
half a pint, has been dissolved in gentle heat, in a suitable lamp, with
an argand chimney to prevent flickering, will be sufficient.
We should add that a tin chimney, bent as in magic lanterns, will, of
course, be required to complete the apparatus.
[Illustration]