Scientific American Supplement, No. 561, October 2, 1886Various
Science
Scientific American Supplement, No. 561, October 2, 1886
Various
Science -- Periodicals
The Lippmann establishment at once offered to make a boring by means
of which it would be possible to communicate with the galleries in
which the men were imprisoned, but, despite the most active efforts,
success was found impossible. In order to satisfy public opinion, the
committee resolved to bore a well 12 inches in diameter to a depth of
23 feet, that should permit of reaching the gallery; but this did not
render the latter accessible. How was it to be seen what had occurred,
how was it to be made certain that the men were dead, and that all
hope of rescue must be abandoned? To Mr. Langlois, a Parisian
photographer, was confided an order to construct a special apparatus
which might be let down to the bottom of the well by a cord, and
which, being capable of operating from a distance, should furnish the
required information through sensitized plates. As may be seen, this
operation presented peculiar difficulties, although Mr. Langlois was
enabled to overcome these with much skill.
The photographic apparatus that the ingenious operator constructed was
contained in a metallic case that could be let down into the bore
hole. The upper and lower parts of the contrivance were provided with
incandescent lamps, that could be lighted or extinguished from a
distance, by means of conductors. The photographic apparatus, properly
so called, formed of an objective and camera with its sensitized
plate, was inclosed in a cylinder 31/2 inches in diameter. By means of a
cord drawn at the mouth of the well, the apparatus could be made to
issue from its vertical sheath, and to pivot around its axis so as
take views in different directions (Fig. 1).
The entire affair was suspended by twelve-foot iron rods, connected
with each other end for end.
In using the apparatus, the operating was done in a shanty, which
served as a dark room. The device was let down into the bore well
until it touched bottom. At this moment a cord was pulled so as to
raise the camera, and then a few moments were allowed to elapse in
order that the apparatus might become immovable. As the objective was
all the time in the dark, it had neither cap nor shutter, but was
unmasked from the beginning of the operation.
In order to form an impression on the plate, it was only necessary to
give light; this being easily done by passing an electric current by
means of a commutator, so as to light the incandescent lamps. At the
end of the exposure, the lamps were extinguished and the entire
apparatus was immersed in darkness. The mean time of exposure was from
four to five minutes. The apparatus was then hauled up, and the
negative developed.
The experiments could be renewed as often as necessary, and the
apparatus be pointed in all directions by turning it a certain number
of degrees by means of a lever attached to the upper rod. In this way
were obtained various views of the inaccessible gallery in different
planes.
Public-domain text, read in full here on John Shaqi.
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