Napoleon’s telegraph

Napoleon used every tool at his disposal to maintain his power over France, including telecommunications.

I hadn’t known about it either, till I read James Gleick’s The Information. He tells the story of the télégraphe in 19th-century France, devised by the Chappe brothers. It was similar to the “clacks” in Terry Pratchett’s Discworld novels, a system of towers for sending encoded messages visually over long distances. At its height, the system stretched to every corner of France. It used some remarkably modern communication concepts.

The encoding system permitted 98 values by the positioning of beams and arms. Six of them were reserved for “control characters,” as we might call them today, such as start, stop, acknowledgement, and failure. After taking power in 1799, Napoleon used the system to send the message to Lyon, Brest, and Strasbourg: “Paris est tranquille et les bon citoyens sont contents.”

Transmission of messages was very slow and error-prone. Each relay station had to be within sight of the next, and each one could introduce errors or lose the whole message. In warm weather one message in three was lost, and in winter only one message in three arrived. At night no transmission was possible.

Napoleon banned using the system for non-governmental purposes. After his time, an 1837 law criminalized unauthorized télégraphe communication. Just a few years later, though, it was a relic of the past, replaced by the electric telegraph. Governments lost their stranglehold on communication, and people could send fast long-distance messages for business or personal reasons.