The Chappe Optical Telegraph

Joshua Foer is a guest blogger on Boing Boing. Joshua is a freelance science journalist and the co-founder of the Atlas Obscura: A Compendium of the World's Wonders, Curiosities, and Esoterica, with Dylan Thuras.

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Before the telegraph, there was the optical telegraph, a chain of towers topped by large pivoting cross members, and spaced as far apart as the eye could see. Developed by the Frenchman Claude Chappe at the end of the 18th century, optical telegraph lines once stretched from Paris out to Dunkirk and Strasbourg, and were in service for more than half a century:

Chappe created a language of 9,999 words, each represented by a different position of the swinging arms. When operated by well-trained optical telegraphers, the system was extraordinarily quick. Messages could be transmitted up to 150 miles in two minutes.

Several optical telegraph relay stations are still around, including one in Saverne, France that was renovated in 1998.

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