Chappe telegraph system. Demonstration, in 1791, of the telegraph system of the brothers Chappe. This early telegraph sent messages quickly over long distances. On 2 March 1791, the brothers transmitted a message from Brulon (16 kilometres away, centre left) to an identical set-up at Parce (foreground). A system of pendulum weights rotated a pointer on a clock face at each location. Flipping a large black and white card synchronised the pointers and transmissions. A group of officials watched the demonstration. Artwork from 'Electricite' (1911) by Max de Nansouty, part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.