By MONS. SENLECQ, of Ardres.
This apparatus, which is intended to transmit to a distance through a
telegraphic wire pictures taken on the plate of a camera, was invented in
the early part of 1877 by M. Senlecq, of Ardres. A description of the first
specification submitted by M. Senlecq to M. du Moncel, member of the
Paris Academy of Sciences, appeared in all the continental and American
scientific journals. Since then the apparatus has everywhere occupied the
attention of prominent electricians, who have striven to improve on it.
Among these we may mention MM. Ayrton, Perry, Sawyer (of New York),
Sargent (of Philadelphia), Brown (of London), Carey (of Boston), Tighe (of
Pittsburg), and Graham Bell himself. Some experimenters have used many
wires, bound together cable-wise, others one wire only. The result has
been, on the one hand, confusion of conductors beyond a certain distance,
with the absolute impossibility of obtaining perfect insulation; and,
on the other hand, an utter want of synchronism. The unequal and slow
sensitiveness of the selenium likewise obstructed the proper working of the
apparatus. Now, without a relative simplicity in the arrangement of the
conducting wires intended to convey to a distance the electric current with
its variations of intensity, without a perfect and rapid synchronism
acting concurrently with the luminous impressions, so as to insure the
simultaneous action of transmitter and receiver, without, in fine, an
increased sensitiveness in the selenium, the idea of the telectroscope
could not be realized. M. Senlecq has fortunately surmounted most of these
main obstacles, and we give to-day a description of the latest apparatus he
has contrived.