27th January 1926.
Inventions rely on the contribution of many pioneers having gone before. This is especially seen in the development of television which for ingenuity is a high-point in the history of science and technology.
Television is transmission of sound and picture signals by radio waves. It recaptures ‘still pictures’ and by presenting these as frames they appear to our eyes to move like ‘flick-books’.
In 1908 John Logie Baird wrote to the magazine Nature on the problems of electric vision and suggested that the way to get a good picture was to connect 90,000 photo-electric cells at the transmitter each through a separate wire to a corresponding point in the receiver.
The letter interested the Scottish-born electrical engineer Alan Archibald Campbell-Swinton who started to think of carrying all the information on a single wire.
It was Today in 1926 that John Logie Baird (1888-1946) a Scottish inventor, gave his first public demonstration of a ‘true’ television system in Frith Street, Soho, London. (1)
Two years later journalist Mr Sydney Moseley was invited to Long Acre where the new invention was installed and met Baird. He told Moseley ‘he was having a bad time with the scoffers and sceptics, including the BBC and part of the technical press, who are trying to ridicule and kill his invention of television at its inception’.
Moseley must have been impressed as he ends with: ‘I think we really have what is called television’.(2)
Baird used the Nipkow rotating, spirally-holed scanning disk for the image and display where the bright light shining through the disk (set with lenses), swept across the subject.
A Selenium photo-electric tube detected the light reflected from the subject converting it into an electric signal which was transmitted by AM radio waves to a receiver where the video signal was applied to a light behind a second Nipkow rotating in synch with the first.(3)
Baird’s mechanical system which in its infancy had a 30-hole scanner producing a 30 scan-line image of his image, was soon superseded by one where moving parts were replaced by the power of the Electron.
Now Analogue has given way to Digital technology.
(1) Baird developed these ideas with Heath Robinson experiments which involved a darning needle for spindle and a circulating spinning holes of a scanning disc cut from an old hat box mounted on a tea chest. An empty biscuit tin housed the projector and bull’s eye lenses were bought at a cycle shop.
(2) He described Baird as, a ‘charming man-a shy, quietly spoken Scot-and would serve as a model for the schoolboy’s picture of a shock-haired, modest, dreamy, absent-minded inventor’.
(3) Selenium which was discovered in the 19thc is in the Oxygen Group of elements.
Moseley journalist and friend of Baird, dates his meeting as 1st August 1928. ‘I watch television, The Private Letters and Diaries of Sydney Moseley 1960 as quoted in Eyewitness Britain. Carroll & Graf. New York 2001 pp 490/1.
history.com/this day in history.
nature.com/1st demo of tv.