Chappe telegraph

Last updated
A restored Chappe telegraph in Marly-le-Roi P1060531 Telegraphe de Chappe Marly.JPG
A restored Chappe telegraph in Marly-le-Roi

The Chappe telegraph was a French semaphore telegraph system invented by Claude Chappe in the early 1790s.

Contents

The system was composed of towers placed every 5 to 15 kilometers. Coded messages were sent from tower to tower, with transmission being handled by tower operators using specially designed telescopes. The messages were decoded once they reached their destination city. By the mid 19th century, the network spanned several hundred kilometres and covered most major French cities as well as Venice, Mainz and Amsterdam.

The system was dismantled after the introduction of the electric telegraph. Today, about twenty Chappe towers remain, in varying states of repair.

Design

Diagram of a Chappe telegraph. The regulator is segment AB. The indicators are segments AC and BD. The mast is the vertical beam. At its base is the mechanical device (the manipulator), which the operator uses to form the signal and which reproduces it in miniature (segments ac and bd). Telegraphe Chappe 1.jpg
Diagram of a Chappe telegraph. The regulator is segment AB. The indicators are segments AC and BD. The mast is the vertical beam. At its base is the mechanical device (the manipulator), which the operator uses to form the signal and which reproduces it in miniature (segments ac and bd).

The Chappe telegraph system embodied varying designs, with the variation partly due to technological improvements made as the system was used. [1]

Physical layout of the towers

The typical tower's signaling mechanism was visible through specially designed telescopes from a neighboring tower, 5 to 15 km away. The mechanism consisted of: [2]

The regulators and indicators had fixed louvres to reduce wind resistance. [5]

Telescopes

Two telescopes were used in each tower to see the signals up- and downstream from that tower. They had magnifications between 30× and 65×, depending on the arrangement of the towers. Each telescope was mounted in a wooden housing that kept it fixed and focused on one of the neighbouring towers. [6] This avoided the need to adjust the telescope for each message.

Coding and deciphering

List of numerical values of Chappe signals. Document preserved in the museum of Saint-Marcan. GrilleDesSignauxDeCorrespondance.JPG
List of numerical values of Chappe signals. Document preserved in the museum of Saint-Marcan.

The code was based on different configurations of the moving parts of the telegraph. The regulator could take two positions (horizontal and vertical) and each of the indicators could take seven positions. Thus, the total number of possible signals was 2 × 7 × 7 = 98. Six of these signals were reserved for service purposes, for example to signal "end of message" or to indicate an error or the absence of an operator. This left 92 possible signals, each associated with a number, used to communicate the message itself. [7] The telegraph configurations corresponding to each number (1-92) are shown in the image on the left.

Page from the Chappe telegraph code book ExtraitDuVocabulaire.JPG
Page from the Chappe telegraph code book

The message was coded at the tower of origin using a code book and decoded at the destination tower using an identical book. The code book contained 92 pages, each of which contained 92 entries, each with a word, a series of related words, or an expression. Messages were composed of words and expressions from the 8464 (92 × 92) possible choices. [8] For each word or expression, two symbols were transmitted; the first indicated the page number for the word or expression, and the second indicated the word's position on the code book's page. [8] For example, as shown in the photo on the right, the code for "ignorance" would be (50, 87) since the word is on page 50 in position 87.

History

Communication over long distances is a recurrent problem in history. This problem was particularly pressing in France at the height of the French Revolution, as the country was surrounded by the hostile forces of Britain, Austria, Prussia and the Netherlands. In this context, France would obtain strategic advantage if, unlike its enemies, it had a rapid system of reliable communication.

The telegraph Chappe provided just such a system of rapid and reliable communication. For example, sending a message carried by horses from Strasbourg to Paris took 4 days. With the Chappe telegraph, it took 2 hours. [9]

Construction of the system began in the early 1790s and proceeded rapidly after that. It continued to be used for decades, but its decline began when the first electric telegraph line, based on International Morse code, was set up in 1845. The last signal from a Chappe telegraph was sent in 1854. [10]

Invention

Claude Chappe, 1765-1828 AduC 175 Chappe (Claude, 1765-1828).JPG
Claude Chappe, 1765-1828

In 1791, Chappe conceived a project that was to put "the government in a position to transmit its orders over a great distance in the least possible time". [4] Having experimented with several solutions involving both sight and sound, he finally opted for the transmission of optical signs via a semaphore system with transmission effected by observation through a telescope. [3] Chappe found experimentally that the angle of the moving pieces of the telegraph was easier to discern accurately at a distance than other characteristics of the towers or other sources of signal.

On 2 and 3 March 1791, Chappe tested an optical telegraph with a system of synchronized pendulums and a white and black optical panel between the cities of Brûlon and Parcé in the Loire region. He then transmitted the following message: "The National Assembly will reward experiences that are useful to the public." [11]

Model of Chappe telegraph that was shown to the Legislative Assembly by Chappe in April 1792 Model of Chappe telegraph.jpg
Model of Chappe telegraph that was shown to the Legislative Assembly by Chappe in April 1792

In June 1791, Chappe moved to Paris and carried out new experiments in Ménilmontant, on a site near what is now the rue du Télégraphe in the 20th arrondissement of Paris (this is the highest point in the city). Chappe and his associates then sought political support in order to install the system throughout France. On 22 March 1792 Chappe submitted a petition to the Legislative Assembly, in which he described his invention as "a reliable means of establishing a correspondence such that the legislative body can send its orders to our frontiers and receive the answer during the duration of the same session." [12] [13] On 1 April a report vaunting the military use of the telegraph was presented to the National Convention on behalf of the Committees for Public Instruction and War. [14]

On 12 July 1793 a successful first test was carried out over a distance of 26 km, between Ménilmontant, Écouen and Saint-Martin-du-Tertre (in the Val-d'Oise, near Paris). On 25 July Chappe was appointed telegraph engineer by decree. After a convincing presentation by Joseph Lakanal in support of the project, the National Convention approved the construction of the Paris-Lille telegraph line on 4 August 1793. [15] In a letter sent the following day, Chappe described the benefits of the system for the political unification of France as follows:

The establishment of the telegraph is, in fact, the best response to authors who think that France is too large to form a Republic. The telegraph shortens distances and somehow unites an immense population at a single point. [16]

Construction

Cover of an Alsatian almanac from 1837, showing the Strasbourg cathedral with a Chappe telegraph on its roof. Der Strassburger hinkende Bote (1837).jpg
Cover of an Alsatian almanac from 1837, showing the Strasbourg cathedral with a Chappe telegraph on its roof.

The first Chappe telegraph line was a series of towers linking Paris and Lille, a distance of 230 kilometres. The Paris-Lille line was operational for military purposes only. Its fifteen towers made it possible to transmit a short message between these two cities within 9 minutes. Later developments added the major French cities, with Paris being the central node of the system. Between Paris and Brest in Brittany, 58 stations dotted the route. [17] In addition to Paris-Lille in 1794, other cities initially served were: Strasbourg in 1798 and Brest in 1799. By 1844, 534 towers criss-crossed French territory, linking the 29 most important cities and covering more than 5,000 km. [18]

The network was also extended in Europe as far as Amsterdam, Mainz and Venice, [18] and in North Africa, where it covered Algeria (Algiers-Oran and Algiers-Constantine in 1853) and Tunisia (Tunis-La Goulette and Tunis-Mohamedia in 1848–1849). [19]

Originally, the mechanisms were built by the workshops of the central administration in the premises of the administration of the telegraph. From 1833 onwards, they were built in Paris in a workshop. This workshop specialised in the manufacture of telegraphs and other machines and was located at 882, passage du Désir, faubourg Saint-Denis in what is now the 10th arrondissement of Paris. [20]

The telescopes used in the system were originally produced in England, but were very expensive. The government encouraged the development of French production capabilities, which eventually replaced English sources. [6]

Management and personnel

A Chappe tower at 103, rue de Grenelle in the 7th arrondissement of Paris Telegraphe de Chappe Paris 7e 001.jpg
A Chappe tower at 103, rue de Grenelle in the 7th arrondissement of Paris

Originally, the system was managed by Claude Chappe and his brothers. This family-based system lasted until the July Monarchy in 1830, after which it was replaced by an administrative system that was both hierarchical and military in style. Under it, three top administrators managed four departments (messaging, personnel, plant and equipment, and accounting). The headquarters were located in the 7th arrondissement of Paris. [21]

At the operational level, directors were responsible for coding, decoding, distributing and entering telegraph dispatches. Below them, inspectors were tasked with overseeing groups of about ten towers, including keeping the plant and equipment in good working order, supervising the tower operators, identifying the source of transmission errors and sanctioning operators for poor performance. [21] The inspectors used military telescopes to observe and evaluate the performance of individual towers. [6]

The tower operators accounted for more than 90 percent of the system's personnel. Originally, each tower had two operators, one for reading the signals and the other for manipulating the transmission mechanism. The operators did not have the code book needed to decipher the signals. Operators also had to verify that the next tower down the line did not make a mistake when retransmitting the message. [22] The operators worked 365 days per year, were sanctioned for mistakes and were paid the same wages as a construction day-worker. Later, because of funding problems, often only one operator was assigned to each tower. [21]

Use and misuse

A Chappe Telegraph dispatch sent on 24 August 1838 from Paris to Toulouse announcing the birth of the first son of the Duc d'Orleans. The message was transmitted in two and a half hours. Depeche telchappe.jpg
A Chappe Telegraph dispatch sent on 24 August 1838 from Paris to Toulouse announcing the birth of the first son of the Duc d'Orléans. The message was transmitted in two and a half hours.

The towers were effective in allowing news to travel quickly around France. The first military use of the system was made to report the recapture from Austrian forces of the cities of Le Quesnoy on 15 August 1794 and the town of Condé-sur-l'Escaut on 30 August 1794. The news of these victories was known by the National Convention in Paris within a few minutes. [23]

Private parties also took steps to profit from the rapid communications offered by the Chappe telegraph. Between 1834 and 1836, the telegraph was used by two Bordeaux businessmen, the brothers François and Joseph Blanc, to receive information on Paris Stock Exchange annuity prices before anyone else. The use was discovered in 1836 and the two brothers spent time in jail awaiting trial but were ultimately found not guilty because there was no law against this behaviour, although they did have to pay a fine for bribing some of the telegraph operators. [24]

Reception by French society

The first phases of construction of the system aroused the suspicions of the population. In several instances, the local telegraphs were destroyed during popular uprisings, [25] possibly due to suspicions of witchcraft, but more probably in order to hinder government communications. [26]

Many French writers of the time featured the telegraph in their writings (Hugo, Dumas, Chateaubriand, Stendhal, Flaubert). Alexandre Dumas incorporated it into his novel, The Count of Montecristo, with the Count pirating the system (through bribery) in order to undermine the financial position of one of his enemies. Victor Hugo described his horror at discovering, while traveling in Normandy in 1836, that the statue of the Archangel on the pinnacle of the steeple of the abbatial church of Mont Saint Michel had been replaced by a Chappe telegraph. [7]

See also

Related Research Articles

<span class="mw-page-title-main">Electrical telegraph</span> Early system for transmitting text over wires

Electrical telegraphy is a point-to-point text messaging system, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems called telegraphs, that were devised to send text messages more quickly than physically carrying them. Electrical telegraphy can be considered the first example of electrical engineering.

<span class="mw-page-title-main">Émile Baudot</span> French telegraph engineer and inventor

Jean-Maurice-Émile Baudot, French telegraph engineer and inventor of the first means of digital communication Baudot code, was one of the pioneers of telecommunications. He invented a multiplexed printing telegraph system that used his code and allowed multiple transmissions over a single line. The baud unit was named after him.

<span class="mw-page-title-main">Telegraphy</span> Long distance transmission of text

Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined, so such systems are thus not true telegraphs.

<span class="mw-page-title-main">Optical telegraph</span> Tower-based signaling network

An optical telegraph is a line of stations, typically towers, for the purpose of conveying textual information by means of visual signals. There are two main types of such systems; the semaphore telegraph which uses pivoted indicator arms and conveys information according to the direction the indicators point, and the shutter telegraph which uses panels that can be rotated to block or pass the light from the sky behind to convey information.

<span class="mw-page-title-main">Claude Chappe</span> Late 18th-century French inventor

Claude Chappe was a French inventor who in 1792 demonstrated a practical semaphore system that eventually spanned all of France. 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 a telescope, then passed it on to the next tower. This was the first practical telecommunications system of the industrial age, and was used until the 1850s when electric telegraph systems replaced it.

<span class="mw-page-title-main">Optical communication</span> Use of light to convey information

Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices. The earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the photophone, invented in 1880.

<span class="mw-page-title-main">Télégraphe station</span> Metro station in Paris, France

Télégraphe is a station on Line 11 of the Paris Métro in the 19th and 20th arrondissements. It is named after the nearby rue de Télégraphe, which was once a chemin de ronde of the park of the Château de Ménilmontant. Its name comes from the optical telegraph invented by Claude Chappe (1763–1805) in 1792. This was the first practical telecommunications system, but was eventually replaced by the electric telegraph. Chappe installed the relay station, containing the telegraph's apparatus which he called a tachygraphe, on this peak of 128 meters altitude.

A telegraph code is one of the character encodings used to transmit information by telegraphy. Morse code is the best-known such code. Telegraphy usually refers to the electrical telegraph, but telegraph systems using the optical telegraph were in use before that. A code consists of a number of code points, each corresponding to a letter of the alphabet, a numeral, or some other character. In codes intended for machines rather than humans, code points for control characters, such as carriage return, are required to control the operation of the mechanism. Each code point is made up of a number of elements arranged in a unique way for that character. There are usually two types of element, but more element types were employed in some codes not intended for machines. For instance, American Morse code had about five elements, rather than the two of International Morse Code.

<span class="mw-page-title-main">History of telecommunication</span>

The history of telecommunication began with the use of smoke signals and drums in Africa, Asia, and the Americas. In the 1790s, the first fixed semaphore systems emerged in Europe. However, it was not until the 1830s that electrical telecommunication systems started to appear. This article details the history of telecommunication and the individuals who helped make telecommunication systems what they are today. The history of telecommunication is an important part of the larger history of communication.

<span class="mw-page-title-main">Saint-Michel-Tubœuf</span> Commune in Normandy, France

Saint-Michel-Tubœuf is a commune in the Orne department in north-western France. The commune was formed in 1965 by the merger of the former communes Saint-Michel-la-Forêt and Tubœuf.

<span class="mw-page-title-main">Louis Bastien (Esperantist)</span> French Esperantist and quartermaster

Louis Marie Jules Charles Bastien was a French Esperantist and a quartermaster in the French army. In 1899 he married Marguerite Pfulb (1879–1941); the couple had three daughters and two sons. In school he learned mathematics, classical French literature, Latin and Greek and learned to compose Latin verse. After a year of preparatory studies at l'Ecole Sainte-Geneviève in Versailles he entered l'Ecole Polytechnique in 1887 at the age of 17. Not having the maturity of his older classmates, he did not excel in his studies and, on graduation in 1889, had to content himself with a military career.

<span class="mw-page-title-main">Prussian semaphore system</span>

The Prussian semaphore system was a telegraphic communications system used between Berlin and the Rhine Province from 1832 to 1849. It could transmit administrative and military messages by optical signal over a distance of nearly 550 kilometres (340 mi). The telegraph line comprised 62 stations each furnished with a signal mast with six cable-operated arms. The stations were equipped with telescopes that operators used to copy coded messages and forward them to the next station. Three dispatch departments located in Berlin, Cologne and Koblenz handled the coding and decoding of official telegrams. Although electric telegraphy made the system obsolete for military use, simplified semaphores were still used for railway signals.

<span class="mw-page-title-main">Jean-Baptiste Chappe d'Auteroche</span> French astronomer

Jean-Baptiste Chappe d'Auteroche was a French astronomer, best known for his observations of the transits of Venus in 1761 and 1769.

<span class="mw-page-title-main">Fort du Télégraphe</span>

The Fort du Télégraphe, or Fort Berwick, is located in the Maurienne valley on the road to the Col du Galibier between Valloire and Saint-Michel-de-Maurienne, at the Col du Télégraphe, dominating the valley of the Arc. The location at an altitude of 1,585 metres (5,200 ft) previously accommodated a telegraph of the Chappe system using articulating arms to send messages between Lyon and Milan, and after 1809, Venice. The fort has two entrances with drawbridges to allow access to different levels of the fort, with inclined ramps to allow easy movement of artillery pieces. When completed in 1884 after four years of construction, the fort was manned by 170 men, firing four artillery pieces at the main fort and four more at detached batteries.

<span class="mw-page-title-main">Juliette Dodu</span>

Juliette Dodu was a legendary heroine of the Franco-Prussian War of 1870, and the first woman to be awarded the Legion of Honor. However, many doubts have been raised about her actions during the war, and her story remains controversial.

<span class="mw-page-title-main">Fort de Valros</span> Ruined fortress at Valros, France

The Fort de Valros is a ruined small castle or fortress in the commune of Valros in the Hérault département of France. In the mid-19th century, the fort was the site of a semaphore station.

<span class="mw-page-title-main">Semaphore</span> Mechanical apparatus used to send messages

Semaphore is the use of an apparatus to create a visual signal transmitted over distance. A semaphore can be performed with devices including: fire, lights, flags, sunlight, and moving arms. Semaphores can be used for telegraphy when arranged in visually connected networks, or for traffic signalling such as in railway systems, or traffic lights in cities.

<span class="mw-page-title-main">Pierre-sur-Haute military radio station</span> French military communications site

The Pierre-sur-Haute military radio station is a French military communications site that has been in use since 1913. The 30-hectare (74-acre) station is located on a hilltop in the Sauvain and Job communes. The site contains three towers, the tallest of which is a 55-metre-high civilian telecommunication tower owned by Télédiffusion de France.

<span class="mw-page-title-main">Foy–Breguet telegraph</span> Type of electrical telegraph

The Foy–Breguet telegraph, also called the French telegraph, was an electrical telegraph of the needle telegraph type developed by Louis-François-Clement Breguet and Alphonse Foy in the 1840s for use in France. The system used two-needle instruments that presented a display using the same code as that on the optical telegraph of Claude Chappe. The Chappe telegraph was extensively used in France by the government, so this arrangement was appealing to them as it meant there was no need to retrain operators.

<span class="mw-page-title-main">Paris pneumatic post</span> Pneumatic tube messaging service

The Paris pneumatic post was a pneumatic tube message-carrying service that operated in the French capital from 1866. It was established because of the popularity of the electric telegraph in the city which had led to the signal cables becoming overloaded and messages being sent by road. The pneumatic system allowed the telegraph companies to send messages underground through sealed lines laid in the Paris sewers, bypassing any traffic on the roads above. The network was taken into public ownership in 1879, under the Ministry of Posts and Telegraphs, and opened to messages sent by the general public. Messages continued to be considered officially as telegrams and for a fixed cost users could write a message on a "petit bleu" form to be sent anywhere in the city. After arriving at the office nearest the recipient it would be taken to their address by a courier.

References

  1. "Les techniques du télégraphe Chappe". www.telegraphe-chappe.com. Retrieved 2023-05-31.
  2. "TÉLÉCOMMUNICATIONS - Histoire, Le télégraphe optique - Encyclopædia Universalis". www.universalis.fr. Retrieved 2023-05-30.
  3. 1 2 Mahoney, Michael S. (1997). "Review of The Early History of Data Networks". Technology and Culture. 38 (4): 1004–1006. doi:10.2307/3106983. ISSN   0040-165X.
  4. 1 2 Chappe, cited by Patrice Flichy, Ignace, quote from 1840 cited by Patrice Flichy (1997). Une histoire de la communication moderne: Espace public et vie privée. La Découverte.{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  5. Cahiers de la FNARH, numéro 100, pages 15 à 19.
  6. 1 2 3 "Les lunettes". www.telegraphe-chappe.com. Retrieved 2023-05-31.
  7. 1 2 "Le télégraphe de Chappe animation codage décodage". therese.eveilleau.pagesperso-orange.fr. Retrieved 2023-05-31.
  8. 1 2 "Le code ou vocabulaire Chappe". telegraphe-chappe.com. Retrieved 2023-07-03.
  9. "Communiquer a distance : le telegraphe Chappe". www.telegraphe-chappe.com. Retrieved 2023-05-31.
  10. "Le réseau Chappe". www.telegraphe-chappe.com. Retrieved 2023-05-31.
  11. Flichy, Patrice (1997). Une histoire de la communication moderne: Espace public and vie privée. La Découverte.
  12. Gerspach, Edouard, quote from 1860 cited by Patrice Flichy (1997). Une histoire de la communication moderne: Espace public et vie privée. La Découverte.{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  13. Koenig, Duane (1944). "Telegraphs and Telegrams in Revolutionary France". The Scientific Monthly. 59 (6): 431–437. ISSN   0096-3771.
  14. Flichy, Patrice (1997). Une histoire de la communication moderne: Espace public et vie privée[A History of Modern Communication: Public Space and Private Life] (in French). La Découverte. pp. 20–21.
  15. "Les premières expériences". www.telegraphe-chappe.com. Retrieved 2023-05-31.
  16. "Le télégraphe Chappe". www.histoire-image.org. Retrieved 13 December 2018..
  17. Henri Chalm, Des télégraphes et des hommes, éditions Henri Chalm, Plonéis, 2021, ISBN   978-2-9540923-1-7.
  18. 1 2 "La fin des lignes de télégraphie Chappe". www.telegraphe-chappe.com. Retrieved 2023-05-31.
  19. "Le réseau Chappe : Afrique du Nord". www.telegraphe-chappe.com. Retrieved 2021-05-19..
  20. Catherine Bertho, Télégraphes et téléphones, de Valmy au microprocesseur, Éditions Le Livre de Poche, Paris, 1981, numéro 5581, ISBN   2-253-02832-0.
  21. 1 2 3 "Les hommes du télégraphe". www.telegraphe-chappe.com. Retrieved 2023-05-31.
  22. "The Optical Telegraph: Faster than a Messenger on Horseback : History of Information". www.historyofinformation.com. Retrieved 2023-05-31.
  23. Mission du bicentenaire de la Révolution française (1989). Les héritages de la révolution (in French). Besançon: Babylone. ISBN   2-907742-01-9.
  24. "Le " piratage " du réseau Chappe, ancêtre des cyber-attaques modernes - Déjà-vu". blog.francetvinfo.fr (in French). 2017-10-10. Retrieved 2023-05-30.
  25. "Le télégraphe Chappe". www.histoire-image.org. Retrieved 13 December 2018..
  26. "Claude Chappe" . Retrieved 13 December 2018..