Hughes's printing telegraph, c 1855.
© Science Museum / Science & Society Picture Library
Engraving by Laplante after Bonnafoux. British physicist David Edward Hughes (1831-1900) invented this successful telegraph in 1855. It was the first telegraph system which printed the text at the sending and receiving ends, abolishing the need for a special alphabetic code. It employs synchronised type-wheels at each end of the line. Pressing the keys raises pins opposite the required letters. When a pin makes contact, a hammer pushes the paper against the type-wheel and prints the corresponding letter. An experienced operator could send messages of up to 30 words a minute. The system was mainly used on cable routes from Britain to Europe. Illustration from 'Electricity and Magnetism' by Amedee Guillemin (1826-1893), published in London in 1891.