Rignoux and Fournier Scheme
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.)