18th June 1908. Envisioning the Future.
Whilst everyone has heard of Logie-Baird, few have come across A.A. Campbell-Swinton one of the early pioneers of ‘distance vision via radio transmission’: television.(1)
Having launched Marconi on his career, with a letter of introduction to Sir William Preece Engineer-in-Chief, of the General Post Office, Campbell-Swinton became involved with work on the newly-discovered cathode rays, as an oscilloscope, which made visible the wave form of alternating currents.
Though there were many in the field at the time, Campbell-Swinton has the credit for pushing the case for the Cathode Ray Tube (CRT) television based electronic system, which finally triumphed over that of Baird’s electro-mechanical, and has stood the test of time until recently.
It was an amazing piece of scientific clairvoyance comparable to Babbage’s anticipation of the principle of the computer.
It was Today in 1908 that Alan Archibald Campbell Swinton F.R.S., who had previously worked on X-rays, had a letter published in the magazine Nature on Distant Electric Vision.
It was in response to Sheldon Bidwell’s previous letter, entitled: ‘Telegraphic Photography and Electric Vision’, concerned about the problem of synchronizing transmission and reception of images.(2)
Campbell-Swinton said that the problems of distant electric vision, ‘can probably be solved by employment of two beams of Cathode Rays, one at the transmitter- which was a new idea- and one at the receiving station.
Also Bidwell’s 90,000 ‘elements’, photo-electric cells (pixels), scanning at 10 times a second would be better replaced by Braun’s Cathode Ray Oscilloscope. Further, the same device could be used as a receiver, creating a patch of light corresponding to the amount of light falling on each photo-cell.(3)
By the 1920s the problems of mechanical scanning of the Baird system, and its poor resolution were recognized, and in June 1928, in the Modern Wireless Magazine, ‘TV by Cathode Ray’, by Campbell-Swinton came at a time when the argument had not been finally won. It was in the article that he suggested abandoning mechanical scanning in favour of the ‘more promising imponderable electrons’.
‘In fact it was only an idea’ as Campbell-Swinton later wrote, and required the invention of the electronic amplifier, the development of much-improved photo-cells and cathode-ray tubes.
The scientist died in 1930, a few years before the final vindication of his distant electronic vision.
(1) Campbell-Swinton (1863-1930) had started experimenting in 1903 with Cathode Ray Tubes and electronic transmission.
(2) Bidwell published his findings in Nature 4.6.1908, on Telegraphic Photography and Electrical Vision.
(3) Campbell-Swinton’s camera stored the amount of light falling on each photo-cell ‘element’ during the whole period, so that when that cell was switched on by the cathode-ray beam, the message sent to the receiver was the sum of all the light that had fallen on the cell since it was last switched on.
Ref: wikipedia.org/shelford_ bidwell.
Ref: dunsehistoryof science.co.uk/campbell-swinton.
Ref: thesun.org.uk/googleimages:Image reference.