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Chappe company logo |
Claude Chappe invented an optical system for sending messages in 1792. He equipped towers with mechanical arms whose positions indicated numbers that stood for words. The signals could be seen by telescope and relayed from tower to tower.
Mercury, Roman messenger of the gods, is shown carrying a Chappe semaphore. Beneath him, two signal towers face each other across a body of water.
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Semaphore towers were usually about 20 miles (32 km) apart. On a clear day, a short message could travel from Paris to the German border (about 210 miles or 350 km) in about ten minutes. In bad weather or at night, however, the system was virtually useless. |
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Chappe semaphore on the roof of the Louvre, Paris From Beschreibung und Abbildung des Telegraphen, 1795 Smithsonian Institution Libraries | |
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Letter (left, 1809) and money order (right, 1816) sent by Chappe semaphore Smithsonian Institution Libraries | |
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This anonymous German booklet described Chappe's new semaphore system and code. |
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Beschreibung und Abbildung des Telegraphen, oder der neuerfundenen Fernschreibemaschine in Paris [Description and illustration of the telegraph, or the newly invented long-distance message system in Paris] (Leipzig, 1795) Smithsonian Institution Libraries | |
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Map: Semaphore routes in France, early 1800s Adapted from Technische Mitteilungen der schweizerischen Telegraphen- und Telephon Verwaltung 17, 1939 Smithsonian Institution Libraries |
