Chappe was born into a wealthy family in 1763 and originally trained as a member of the church. However, the turmoil of the French Revolution meant that he was unable to continue in his position and he returned home to focus on science. Working with his brothers, Chappe began to experiment with optical telegraph designs.
Chappe was not the first person to attempt to create a system of long-distance communication. The English scientist Robert Hooke had presented a proposal a century earlier, but his idea was never implemented. Consequently the Chappe brothers were the first to successfully transmit a message when they demonstrated their system on 2 March 1791, covering more than 16km from Brûlon to Parcé.
Using what became known as the Synchronized System, Chappe was able to transmit the phrase ‘If you succeed, you will soon bask in glory’ in just four minutes. Two pendulum clocks had their faces modified with a series of symbols and, after being synchronised, were placed in the two locations alongside a telescope that pointed to the other. The transmitting station used black and white panels to alert the receiver to when the second hand of the clock was passing over the appropriate symbol, which they then recorded. The string of symbols, when decoded, produced the message.
Chappe soon abandoned synchronised clocks in favour of mechanical arms to portray the different symbols. When mounted on top of a tower, the arms could be seen through a telescope and their alignment either recorded or relayed onwards. A 230km semaphore line of these towers between Paris and Lille was installed in 1792.
