The Other Telegraph

Wednesday, March 16th, 2011

Until 1793, Freeman Dyson reminds us, African drummers were ahead of Europeans in their ability to transmit information rapidly over long distances. Then along came the telegraph — but not the one most people think of:

In 1793, Claude Chappe, a patriotic citizen of France, wishing to strengthen the defense of the revolutionary government against domestic and foreign enemies, invented a device that he called the telegraph. The telegraph was an optical communication system with stations consisting of large movable pointers mounted on the tops of sixty-foot towers. Each station was manned by an operator who could read a message transmitted by a neighboring station and transmit the same message to the next station in the transmission line.

The distance between neighbors was about seven miles. Along the transmission lines, optical messages in France could travel faster than drum messages in Africa. When Napoleon took charge of the French Republic in 1799, he ordered the completion of the optical telegraph system to link all the major cities of France from Calais and Paris to Toulon and onward to Milan. The telegraph became, as Claude Chappe had intended, an important instrument of national power. Napoleon made sure that it was not available to private users.

Unlike the drum language, which was based on spoken language, the optical telegraph was based on written French. Chappe invented an elaborate coding system to translate written messages into optical signals. Chappe had the opposite problem from the drummers. The drummers had a fast transmission system with ambiguous messages. They needed to slow down the transmission to make the messages unambiguous. Chappe had a painfully slow transmission system with redundant messages. The French language, like most alphabetic languages, is highly redundant, using many more letters than are needed to convey the meaning of a message. Chappe’s coding system allowed messages to be transmitted faster. Many common phrases and proper names were encoded by only two optical symbols, with a substantial gain in speed of transmission. The composer and the reader of the message had code books listing the message codes for eight thousand phrases and names. For Napoleon it was an advantage to have a code that was effectively cryptographic, keeping the content of the messages secret from citizens along the route.

Morse launched his electric telegraph in 1838 and perfected his famous code in 1844.

(I’ve mentioned telegraphy without electricity before. It may qualify as an idea behind its time.)


  1. Bruce says:

    “Can we talk about nefers?”, said Susan Brind Morrow in The Dawning Moon of the Mind; Unlocking the Pyramid Texts. Nefers were ancient Egyptian signal flags.

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