The Baker Machine
The machine of the opposite illustration, “the telestereograph,” is the invention of T. Thorn Baker, Esq., of England, and “was used by the London Daily Mirror in July, 1909, and was worked by wire rather regularly between London and Paris, and London and Manchester.” The picture to be sent was “a halftone photograph printed in fish glue on lead foil, and wrapped on a sending cylinder, rotating once every two seconds with a metal point riding on it.”
The receiving cylinder carried “an absorbent paper impregnated with a colorless solution which turns black or brown when decomposed by the incoming electric current.”
What electrolytic solution was employed is not stated in the report, but was probably sodium iodide or potassium bromide judging from the description of its color and behavior.
To synchronize, the receiving drum turns faster than the sending drum, and is caught each revolution until the other catches up. (Smithsonian Report, 1910.)