Banks of valves, descendants of the Fleming vacuum-tube, in a replica of the Colossus computer, the wartime code-cracking machine at Bletchley Park.
FANNY Umphelby’s ‘Child’s Guide To Knowledge’* can have had few readers more devoted, or more distinguished in later life, than Ambrose Fleming.
Her collection of scientific facts sparked his long career at University College, London, and at the Marconi Company, assisting in the first transatlantic radio transmissions.
Those early transmissions relied on instruments such as Marconi’s magnetic detector, or the gloriously-named ‘cat’s whisker’, to detect them.
On November 16, 1904, Fleming patented his ‘thermionic vacuum tube diode’, which harnessed the Edison Effect (the flow of electrons in a vacuum from a hot cathode filament onto an anode plate) to detect and rectify radio waves.
It was far superior to existing devices, robust enough even for the Navy. For the next fifty years, descendants of Fleming valves were at the heart of electronics, from radios and TVs to radar and computers, until superseded by transistors and a new generation of solid-state devices.
Fanny would have been proud.
You can read Mrs Umphelby’s scientific catechism online here. Fleming had it by heart, and would quote from it all his life.
Précis
A children’s book of scientific facts inspired Ambrose Fleming to become an electrical engineer, and in 1904 he patented a device for detecting and rectifying radio waves, the thermionic vaccum tube diode. For fifty years, it remained an indispensable component of electronics, and drove the development of modern TV, radar and radio. (51 / 60 words)
