The Dr. Korn Machine
The accompanying illustration shows the work of a machine developed by Dr. Korn, of Germany, and first used by the Daily Mirror between London and Paris in 1907. “On a revolving glass cylinder” a transparent picture was put. He used a Nernst lamp and “selenium cells on opposite sides of a Wheatstone bridge” to overcome the inherent lag of the selenium cell.
Signals were sent over a wire and received on photographic film on a cylinder, using “two fine silver strings free to move laterally in a strong magnetic field.” A light was focused on the obstructing “silver strings,” which the incoming electric signals, passing through the “strings,” separated to a greater or lesser degree “to widen or thin the photographed line.”
“When the film is developed it is laid out flat, and the spiral line becomes resolved into so many parallel lines.” The sending and the receiving machines were synchronized by “well calibrated clocks which released the cylinders at end of every five seconds.” (Mr. Baker in Smithsonian Report, 1910.)