Zworykin.

In 1923 Russian immigrant Vladimir Zworykin applied for a patent for his iconoscope, a television camera or transmission tube. Many scientists and inventors had been working on the possibility of transmitting pictures ever since the first primitive telegraphs of the 1830s. By 1884 a German inventor, Paul Gottlieb Nipkow, had patented a sort of picture transmitter that used a mechanical scanner projecting onto a photosensitive rotating disk. The problem with Nipkow's invention and other primitive mechanical television prototypes was that they employed hand- or electric-motor-driven devices that projected either light or a stream of electrons sequentially onto a photosensitive surface to "draw" a quick series of pictures that the eye would interpret as a moving picture. Through a phenomenon called "persistence of vision" the eye perceives a series of still pictures as actual motion.

Trial Runs.

In 1927 Bell Labs publicly demonstrated the transmission of mechanically scanned...