One of the early suggestions had for its fundamental principle a surface
studded with thousands of “selenium cells” each a part of an individual
circuit, and upon which a picture was projected. The idea was that the
different cells would transmit a different value of current with each
different intensity of light which made up the picture.
At the distant station a given surface had a corresponding number of
tiny lamps, each attached to its respective cell at the sending station,
and being lighted thereby the ensemble would reproduce the distant
picture.
The scheme is possible but hardly practical, for if only fifty lines per
inch each way were sufficient on a picture but one foot square, there
would have to be three hundred and sixty thousand cells at the sending
end, and a like number of lamps at the receiving end, each but
one-fiftieth of an inch in diameter. Such a problem would seem to
present difficulties, though the author himself in the bravery of
ignorance suggested this very scheme in the _Electrical Engineer_, of
July 25, 1894. (_Illustration by courtesy of Science and Invention._)
[Illustration: [Machines]]