Claude Chappe | |
|---|---|
.JPG) Chappe | |
| Born | 25 December 1763 (1763-12-25) Brûlon, Sarthe, France |
| Died | 23 January 1805 (1805-01-24) (aged 41) Paris, France |
| Engineering career | |
| Projects | Semaphore system |
| Significant advance | Telecommunications |
Claude Chappe (French:[klodʃap]; 25 December 1763 – 23 January 1805) was a French inventor who in 1792 demonstrated a practicalsemaphore system that eventually spanned all ofFrance. His system consisted of a series of towers, each within line of sight of others, each supporting a wooden mast with two crossarms on pivots that could be placed in various positions. The operator in a tower moved the arms to a sequence of positions, spelling out text messages in semaphore code. The operator in the next tower read the message through atelescope, then passed it on to the next tower. This was the first practicaltelecommunications system of theindustrial age, and was used until the 1850s whenelectric telegraph systems replaced it.
Claude Chappe was born in Brûlon,Sarthe, France, the son of Ignace Chappe, acontrôleur (intendant) of theCrown lands forLaval, and his wife Marie Devernay, daughter of aphysician of Laval. He was raised for church service, but lost hissinecure during theFrench Revolution. He was educated at theLycée Pierre Corneille inRouen.[1]
His uncle was the astronomerJean-Baptiste Chappe d'Auteroche, famed for his observations of theTransit of Venus in 1761 and again in 1769. The first book Claude read in his youth was his uncle's journal of the 1761 trip, "Voyage en Siberie". His brother, Abraham, wrote "Reading this book greatly inspired him, and gave him a taste for the physical sciences. From this point on, all his studies, and even his pastimes, were focused on that subject." Because of hisastronomer uncle, Claude may also have become familiar with the properties of telescopes.[2]
He and his four unemployed brothers decided to develop a practical system of semaphore relay stations, a task proposed in antiquity, yet never realized.[3]
Claude's brother, Ignace Chappe (1760–1829) was a member of the Legislative Assembly during theFrench Revolution. With his help, the Assembly supported a proposal to build a relay line from Paris to Lille (fifteen stations, about 120 miles), to carry dispatches from the war.
The Chappe brothers determined by experiment that the angles of a rod were easier to see than the presence or absence of panels. Their final design had two arms connected by a cross-arm. Each arm had seven positions, and the cross-arm had four more, permitting a 196-combination code. The arms were from three to thirty feet long, black, and counterweighted, moved by only two handles. Lamps mounted on the arms proved unsatisfactory for night use. The relay towers were placed from 12 to 25 km (7.5 to 15.5 mi) apart. Each tower had a telescope pointing both up and down the relay line.
Chappe initially called his invention atachygraph ("fast writer").[4] However, theArmy preferred to use the wordtelegraph ("far writer"), which was coined by French statesmanAndré François Miot de Mélito.[5] Today, in order to distinguish it from subsequent telegraph systems, theFrench name for Chappe's semaphore telegraph system is named after him, and thus is known as aTelegraph Chappe.[6] Alternatively, Chappe coined the phrasesemaphore,[7] from theGreek elements σῆμα (sêma, "sign"); and from φορός (phorós, "carrying"),[8] or φορά (phorá, "a carrying") from φέρειν (phérein, "to bear").[9]
In 1794, the first messages were successfully sent betweenParis andLille.[6] In 1794 the semaphore line informed Parisians of the capture ofCondé-sur-l'Escaut from the Austrians less than an hour after it occurred. Other lines were built, including a line from Paris to Toulon. The system was widely copied by other European states, and was used byNapoleon to coordinate his empire and army.[6]
In 1805, Claude Chappekilled himself.[10] He was said to be depressed by illness, and claims by rivals that he had plagiarized from military semaphore systems.
In 1824 Ignace Chappe attempted to increase interest in using the semaphore line for commercial messages, such as commodity prices; however, the business community resisted.
From 1844, the government of France funded trials of a new system ofelectric telegraph lines and committed to fully replacing the Chappe telegraph in 1846. Many contemporaries warned of the ease ofsabotage and interruption of service by cutting a wire. The extent of the French optical telegraph meant that it took some time for the replacement to be completed. The two systems existed side-by-side for about a decade. One of the last messages sent over the Chappe telegraph was news of thefall of Sevastopol in 1855.[11]
The Chappe semaphore figures prominently inAlexandre Dumas'The Count of Monte Cristo. The Count bribes an underpaid operator to transmit a false message.
Rue Chappe in the18th arrondissement of Paris, is named after Chappe.[12] A bronze sculpture of him was erected at the crossing ofRue du Bac andBoulevard Raspail in Paris. As many statues displeased or offended Hitler, it was removed and melted down during theNazi occupation of Paris, in 1941 or 1942.[13]
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