Semaphore telegraph

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A replica of one of Chappe's semaphore towers in Nalbach, Germany OptischerTelegraf.jpg
A replica of one of Chappe's semaphore towers in Nalbach, Germany
Illustration of signaling by semaphore in 18th century France. The operators would move the semaphore arms to successive positions to spell out text messages in semaphore code, and the people in the next tower would read them. Signaling by Napoleonic semaphore line.jpg
Illustration of signaling by semaphore in 18th century France. The operators would move the semaphore arms to successive positions to spell out text messages in semaphore code, and the people in the next tower would read them.

A semaphore telegraph is a system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position. The most widely used system was invented in 1792 in France by Claude Chappe, and was popular in the late eighteenth to early nineteenth centuries. [1] [2] [3] Lines of relay towers with a semaphore rig at the top were built within line-of-sight of each other, at separations of 5 to 20 miles. Operators at each tower would watch the neighboring tower through a spyglass, and when the semaphore arms began to move spelling out a message, they would pass the message on to the next tower. This system was much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. Semaphore lines were a precursor of the electrical telegraph, which would replace them half a century later, and would also be cheaper, faster, and more private. The line-of-sight distance between relay stations was limited by geography and weather, and prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station. Modern derivatives of the semaphore system include flag semaphore (a flag relay system) and the heliograph (optical telegraphy using mirror-directed sunlight reflections).

Claude Chappe French inventor

Claude Chappe was a French inventor who in 1792 demonstrated a practical semaphore system that eventually spanned all of France. This was the first practical telecommunications system of the industrial age, making Chappe the first telecom mogul with his "mechanical internet."

Post riders

Post riders or postriders describes a horse and rider postal delivery system that existed at various times and various places throughout history. The term is usually reserved for instances where a network of regularly scheduled service was provided under some degree of central management by the State or State licensed monopoly.

Electrical telegraph

An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via dedicated telecommunication circuit or radio.

Contents

Etymology and terminology

The word semaphore was coined in 1801 by the French inventor of the semaphore line itself, Claude Chappe. [4] He composed it from the Greek elements σῆμα (sêma, "sign"); and from φορός (phorós, "carrying"), [5] or φορά (phorá, "a carrying") from φέρειν (phérein, "to bear"). [6] Chappe also coined the word tachygraph, meaning "fast writer" [7] . However, the French Army preferred to call Chappe's semaphore system the telegraph, meaning "far writer", which was coined by French statesman André François Miot de Mélito. [8] The word semaphoric was first printed in English in 1808: "The newly constructed Semaphoric telegraphs", referring to the destruction of telegraphs in France. [9] The word semaphore was first printed in English in 1816: "The improved Semaphore has been erected on the top of the Admiralty", referring to the installation of a simpler telegraph invented by Sir Home Popham.[ citation needed ] Semaphore telegraphs are also called "optical telegraphs", "shutter telegraph chains", "Chappe telegraphs" or "Napoleonic semaphore".

Greek language language spoken in Greece, Cyprus and Southern Albania

Greek is an independent branch of the Indo-European family of languages, native to Greece, Cyprus and other parts of the Eastern Mediterranean and the Black Sea. It has the longest documented history of any living Indo-European language, spanning more than 3000 years of written records. Its writing system has been the Greek alphabet for the major part of its history; other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems.

André François Miot de Mélito French politician and diplomat

André François Miot de Mélito (1762–1841) was a French statesman and scholar. His position survived the French Revolution.

Admiralty House, London grade I listed building facing Whitehall in London, England

Admiralty House in London is a Grade I listed building facing Whitehall, currently used for UK government functions and as ministerial flats. It was opened in 1788 and until 1964 was the official residence of the First Lords of the Admiralty.

History

Early designs

Illustration showing Robert Hooke's proposed system. At top are various symbols that might be used; ABCE indicates the frame, and D the screen behind which each of the symbols are hidden when not in use. Rees's Cyclopaedia - Hooke's optical telegraph.png
Illustration showing Robert Hooke's proposed system. At top are various symbols that might be used; ABCE indicates the frame, and D the screen behind which each of the symbols are hidden when not in use.

Optical telegraphy dates from ancient times, in the form of hydraulic telegraphs, torches (as used by ancient cultures since the discovery of fire) and smoke signals. Modern design of semaphores was first foreseen by the British polymath Robert Hooke, who gave a vivid and comprehensive outline of visual telegraphy to the Royal Society in a 1684 submission in which he outlined many practical details. The system (which was motivated by military concerns, following the recent Battle of Vienna in 1683) was never put into practice. [10] [11]

Hydraulic telegraph

A hydraulic telegraph is either of two different hydraulic-telegraph telecommunication systems. The earliest one was developed in 4th-century BC Greece, while the other was developed in 19th-century AD Britain. The Greek system was deployed in combination with semaphoric fires, while the latter British system was operated purely by hydraulic fluid pressure.

Polymath person whose expertise spans a significant number of different subject areas

A polymath is a person whose expertise spans a significant number of subject areas, known to draw on complex bodies of knowledge to solve specific problems.

Robert Hooke English natural philosopher, architect and polymath

Robert Hooke FRS was an English natural philosopher, architect and polymath.

Sir Richard Lovell Edgeworth's proposed optical telegraph for use in Ireland. The rotational position of each one of the four indicaters represented a number 1-7 (0 being "rest"), forming a four-digit number. The number stood for a particular word in a codebook. Rees's Cyclopaedia - Richard Lovell Edgeworth's optical telegraph.png
Sir Richard Lovell Edgeworth's proposed optical telegraph for use in Ireland. The rotational position of each one of the four indicaters represented a number 1-7 (0 being "rest"), forming a four-digit number. The number stood for a particular word in a codebook.

One of the first experiments of optical signalling was carried out by the Anglo-Irish landowner and inventor, Sir Richard Lovell Edgeworth in 1767. [12] He placed a bet with his friend, the horse racing gambler Lord March, that he could transmit knowledge of the outcome of the race in just one hour. Using a network of signalling sections erected on high ground, the signal would be observed from one station to the next by means of a telescope. [13] The signal itself consisted of a large pointer that could be placed into eight possible positions in 45 degree increments. A series of two such signals gave a total 64 code elements and a third signal took it up to 512. He returned to his idea in 1795, after hearing of Chappe's system.

Richard Lovell Edgeworth Anglo-Irish politician

Richard Lovell Edgeworth was an Anglo-Irish politician, writer and inventor.

Horse racing Equestrian sport

Horse racing is an equestrian performance sport, typically involving two or more horses ridden by jockeys over a set distance for competition. It is one of the most ancient of all sports, as its basic premise – to identify which of two or more horses is the fastest over a set course or distance – has been unchanged since at least classical antiquity.

William Douglas, 4th Duke of Queensberry 18th/19th-century Scottish nobleman and gambler

William Douglas, 4th Duke of Queensberry KT was a Scottish nobleman. He was popularly known as Old Q, and was famous for being a great gambler.

Chappe system

19th century demonstration of the semaphore Chappe semaphore.jpg
19th century demonstration of the semaphore

Credit for the first successful optical telegraph goes to the French engineer Claude Chappe and his brothers in 1792, who succeeded in covering France with a network of 556 stations stretching a total distance of 4,800 kilometres (3,000 mi). Le système Chappe was used for military and national communications until the 1850s.

France Republic with mainland in Europe and numerous oversea territories

France, officially the French Republic, is a country whose territory consists of metropolitan France in Western Europe and several overseas regions and territories. The metropolitan area of France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean. It is bordered by Belgium, Luxembourg and Germany to the northeast, Switzerland and Italy to the east, and Andorra and Spain to the south. The overseas territories include French Guiana in South America and several islands in the Atlantic, Pacific and Indian oceans. The country's 18 integral regions span a combined area of 643,801 square kilometres (248,573 sq mi) and a total population of 67.3 million. France, a sovereign state, is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre. Other major urban areas include Lyon, Marseille, Toulouse, Bordeaux, Lille and Nice.

Development

During 1790–1795, at the height of the French Revolution, France needed a swift and reliable communication system to thwart the war efforts of its enemies. France was surrounded by the forces of Britain, the Netherlands, Prussia, Austria, and Spain, the cities of Marseille and Lyon were in revolt, and the British Fleet held Toulon. The only advantage France held was the lack of cooperation between the allied forces due to their inadequate lines of communication. In the summer of 1790, the Chappe brothers set about devising a system of communication that would allow the central government to receive intelligence and to transmit orders in the shortest possible time. On 2 March 1791 at 11am, they sent the message “si vous réussissez, vous serez bientôt couverts de gloire” (If you succeed, you will soon bask in glory) between Brulon and Parce, a distance of 16 kilometres (9.9 mi). The first means used a combination of black and white panels, clocks, telescopes, and codebooks to send their message.

French Revolution social and political revolution in France and its colonies occurring from 1789 to 1798

The French Revolution was a period of far-reaching social and political upheaval in France and its colonies beginning in 1789. The Revolution overthrew the monarchy, established a republic, catalyzed violent periods of political turmoil, and finally culminated in a dictatorship under Napoleon who brought many of its principles to areas he conquered in Western Europe and beyond. Inspired by liberal and radical ideas, the Revolution profoundly altered the course of modern history, triggering the global decline of absolute monarchies while replacing them with republics and liberal democracies. Through the Revolutionary Wars, it unleashed a wave of global conflicts that extended from the Caribbean to the Middle East. Historians widely regard the Revolution as one of the most important events in human history.

Great Britain island in the North Atlantic off the north-west coast of continental Europe

Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of 209,331 km2 (80,823 sq mi), it is the largest of the British Isles, the largest European island, and the ninth-largest island in the world. In 2011, Great Britain had a population of about 61 million people, making it the world's third-most populous island after Java in Indonesia and Honshu in Japan. The island of Ireland is situated to the west of Great Britain, and together these islands, along with over 1,000 smaller surrounding islands, form the British Isles archipelago.

Netherlands Constituent country of the Kingdom of the Netherlands in Europe

The Netherlands is a country located mainly in Northwestern Europe. The European portion of the Netherlands consists of twelve separate provinces that border Germany to the east, Belgium to the south, and the North Sea to the northwest, with maritime borders in the North Sea with Belgium, Germany and the United Kingdom. Including three island territories in the Caribbean Sea—Bonaire, Sint Eustatius and Saba— it forms a constituent country of the Kingdom of the Netherlands. The official language is Dutch, but a secondary official language in the province of Friesland is West Frisian.

The Chappes carried out experiments during the next two years, and on two occasions their apparatus at Place de l'Étoile, Paris was destroyed by mobs who thought they were communicating with royalist forces. However, in the summer of 1792 Claude was appointed Ingénieur-Télégraphiste and charged with establishing a line of stations between Paris and Lille, a distance of 230 kilometres (about 143 miles). It was used to carry dispatches for the war between France and Austria. In 1794, it brought news of a French capture of Condé-sur-l'Escaut from the Austrians less than an hour after it occurred. [14] The first symbol of a message to Lille would pass through 15 stations in only nine minutes. The speed of the line varied with the weather, but the line to Lille typically transferred 36 symbols, a complete message, in about 32 minutes. Another line of 50 stations was completed in 1798, covering 488 km between Paris and Strasbourg. [15]

Technical operation

Diagram showing the Chappe system, as used simply for signalling letters and numbers (though it could also be used in an encoded form) Chappe.svg
Diagram showing the Chappe system, as used simply for signalling letters and numbers (though it could also be used in an encoded form)

The Chappe brothers determined by experiment that it was easier to see the angle of a rod than to see the presence or absence of a panel. Their semaphore was composed of two black movable wooden arms, connected by a cross bar; the positions of all three of these components together indicated an alphabetic letter. With counterweights (named forks) on the arms, the Chappe system was controlled by only two handles and was mechanically simple and reasonably robust. Each of the two 2-metre-long arms could display seven positions, and the 4.6-metre-long cross bar connecting the two arms could display four different angles, for a total of 196 symbols (7×7×4). Night operation with lamps on the arms was unsuccessful. To speed up transmission and to provide some semblance of security, a code book was developed for use with semaphore lines. The Chappes' corporation used a code that took 92 of the basic symbols two at a time to yield 8,464 coded words and phrases.

The revised Chappe system of 1795 provided not only a set of codes but also an operational protocol intended to maximize line throughput. Symbols were transmitted in cycles of "2 steps and 3 movements."

  • Step 1, movement 1 (setup): The indicator arms were turned to align with the cross bar, forming a non-symbol. The crossbar was then moved into position for the current symbol.
  • Step 1, movement 2 (transmission): The indicator arms were positioned for the current symbol. The operator then waited for the downline station to copy it.
  • Step 2, movement 3 (completion): The cross bar was turned to a vertical or horizontal position, indicating the end of a cycle.

In this manner, each symbol could propagate down the line as quickly as operators could successfully copy it, with acknowledgement and flow control built into the protocol. A rate of 2-3 symbols per minute was typical. [16] [17]

Other systems

From 1803 on, the French also used the 3-arm Depillon semaphore at coastal locations to provide warning of British incursions. [1] Many national services adopted signaling systems different from the Chappe system. For example, the UK and Sweden adopted systems of shuttered panels (in contradiction to the Chappe brothers' contention that angled rods are more visible). In Spain, the engineer Agustín de Betancourt developed his own system which was adopted by that state. This system was considered by many experts in Europe better than Chappe's, even in France. In Ireland R.L. Edgeworth was to develop an optical telegraph based on a triangle pointer, measuring up to 16 feet in height. Following a number of years promoting his system, he was to get admiralty approval and engaged in its construction during 1803-4. The completed system ran from Dublin to Galway and was act as a rapid warning system in case on French invasion of the west coast of the Ireland. Despite its success in operation, the receding threat of French invasion was to see the system disestablished in 1804. [18]

Use in various countries

France

The Chappe Network in France Reseau chappe77.png
The Chappe Network in France

After Chappe's initial line (between Paris and Lille), the Paris to Strasbourg with 50 stations followed soon after (1798). By 1824, the Chappe brothers were promoting the semaphore lines for commercial use, especially to transmit the costs of commodities. Napoleon Bonaparte saw the military advantage in being able to transmit information between locations, and carried a portable semaphore with his headquarters. This allowed him to coordinate forces and logistics over longer distances than any other army of his time. However, because stations had to be within sight of each other, and because the efficient operation of the network required well trained and disciplined operators, the costs of administration and wages were a continuous source of financial difficulties. Only when[ when? ] the system was funded by the proceeds of its own lottery did costs come under control.[ clarification needed ][ citation needed ]

A Chappe semaphore tower near Saverne, France Tour du telegraphe Chappe Saverne 02.JPG
A Chappe semaphore tower near Saverne, France

In 1821 Norwich Duff, a young British Naval officer, visiting Clermont-en-Argonne, walked up to the telegraph station there and engaged the signalman in conversation. Here is his note of the man's information:

The pay is twenty five sous per day and he [the signalman] is obliged to be there from day light till dark, at present from half past three till half past eight; there are only two of them and for every minute a signal is left without being answered they pay five sous: this is a part of the branch which communicates with Strasburg and a message arrives there from Paris in six minutes it is here in four.

The network was reserved for government use but in 1834 two bankers, François and Joseph Blanc, devised a way to subvert it to their own ends. [19]

Sweden

A replica of an optical telegraph in Stockholm, Sweden Optical telegraph01 4484.jpg
A replica of an optical telegraph in Stockholm, Sweden

At the same time as Chappe, the Swedish inventor Abraham Niclas Edelcrantz experimented with the optical telegraph in Sweden. In 1794 he inaugurated his telegraph with a poem dedicated to the Swedish King on his birthday. The message went from the Palace in Stockholm to the King at Drottningholm. Edelcrantz eventually developed his own system which was quite different from its French counterpart and nearly twice as fast. The system was based on ten collapsible iron shutters. The various positions of the shutters formed combinations of numbers which were translated into letters, words or phrases via codebooks. The telegraph network consisted of telegraph stations positioned at about 10 kilometres (6.2 mi) from one another. Soon telegraph circuits linking castles and fortresses in the neighbourhood of Stockholm were set up and the system was extended to Grisslehamn and Åland. Subsequently, telegraph circuits were introduced between Gothenburg and Marstrand, at Helsingborg and between Karlskrona and its fortresses. Sweden was the second country in the world, after France, to introduce an optical telegraph network. The Swedish optical telegraph network was restricted to the archipelagoes of Stockholm, Gothenburg and Karlskrona. Like its French counterpart, it was mainly used for military purposes.[ citation needed ]

United Kingdom

Diagram of UK Murray six-shutter system, with shutter 6 in the horizontal position, and shutters 1-5 vertical Murray Shutter Telegraph 1795.png
Diagram of UK Murray six-shutter system, with shutter 6 in the horizontal position, and shutters 1-5 vertical

In Ireland, Richard Lovell Edgeworth returned to his earlier work in 1794, and proposed a telegraph there to warn against an anticipated French invasion; however, the proposal was not implemented. Lord George Murray, stimulated by reports of the Chappe semaphore, proposed a system of visual telegraphy to the British Admiralty in 1795. [3] He employed rectangular framework towers with six, five feet high octagonal shutters on horizontal axes that flipped between horizontal and vertical positions to signal. [20] The Rev. Mr Gamble also proposed two distinct five-element systems in 1795: one using five shutters, and one using five ten foot poles. [3] The British Admiralty accepted Murray's system in September 1795, and the first system was the 15 site chain from London to Deal. [21] Messages passed from London to Deal in about sixty seconds, and sixty-five sites were in use by 1808. [21]

St. Albans High Street in 1807, showing the shutter telegraph on top of the city's Clock Tower. It was on the London to Great Yarmouth line Stalbanshighstreet1807 cropped640.jpg
St. Albans High Street in 1807, showing the shutter telegraph on top of the city's Clock Tower. It was on the London to Great Yarmouth line

Chains of Murray's shutter telegraph stations were built along the following routes: LondonDeal and Sheerness, London—Great Yarmouth and London—Portsmouth and Plymouth. [22] The shutter stations were temporary wooden huts, and at the conclusion of the Napoleonic wars they were no longer necessary, and were closed down by the Admiralty in March 1816. [23]

A replacement system was sought, and of the many ideas and devices put forward the Admiralty chose the simpler semaphore system invented by Sir Home Popham. [2] [3] A Popham semaphore was a single fixed vertical 30 foot pole, with two movable 8 foot arms attached to the pole by horizontal pivots at their ends, one arm at the top of the pole, and the other arm at the middle of the pole. [1] [2] The signals of the Popham semaphore were found to be much more visible than those of the Murray semaphore. [1] Popham's 2-arm semaphore was modeled after the 3-arm Depillon French semaphore. [1] An experimental semaphore line between the Admiralty and Chatham was installed in July 1816, and its success helped to confirm the choice. [23]

Subsequently, the Admiralty decided to establish a permanent link to Portsmouth and built a chain of semaphore stations. Work started in December 1820 [23] and the line was operational from 1822 until 1847, when the railway and electric telegraph provided a better means of communication. The semaphore line did not use the same locations as the shutter chain, but followed almost the same route with 15 stations - Admiralty (London), Chelsea Royal Hospital, Putney Heath, Coombe Warren, Coopers Hill, Chatley Heath, Pewley Hill, Bannicle Hill, Haste Hill (Haslemere), Holder Hill, (Midhurst), Beacon Hill, Compton Down, Camp Down, Lumps Fort (Southsea), and Portsmouth Dockyard. The semaphore tower at Chatley Heath, which replaced the Netley Heath station of the shutter telegraph, has been restored by Surrey County Council and is open to the public.

The Board of Port of Liverpool obtained a Private Act of Parliament to construct a chain of Popham optical semaphore stations from LiverpoolHolyhead in 1825. [24] Many of the prominences on which the towers were built ('telegraph hills') are known as Telegraph Hill to this day. As in France the network required lavish amounts of money and manpower to operate and could only be justified as a defence need.

Other countries

Optical telegraph in the harbour of Bremerhaven, Germany BremerhavenSemaphore.jpg
Optical telegraph in the harbour of Bremerhaven, Germany
Former optical telegraph tower on the Winter Palace in Saint Petersburg, Russia Semaphore Line Tower on Winter Palace.jpg
Former optical telegraph tower on the Winter Palace in Saint Petersburg, Russia

Once it had proved its success, the optical telegraph was imitated in many other countries, especially after it was used by Napoleon to coordinate his empire and army. In most of these countries, the postal authorities operated the semaphore lines.

In Portugal, the British forces fighting Napoleon in Portugal soon found that the Portuguese Army had already a very capable semaphore terrestrial system working since 1806, giving the Duke of Wellington a decisive advantage in intelligence. The innovative Portuguese telegraphs, designed by Francisco Ciera, a mathematician, were of 3 types: 3 shutters, 3 balls and 1 pointer/moveable arm (the first for longer distances, the other two for short) and with the advantage of all having only 6 significant positions. He also wrote the code book "Táboas Telegráphicas", with 1554 entries from 1 to 6666 (1 to 6, 11 to 16,... 61 to 66, 111 to 116,... etc.), the same for the 3 systems. Since early 1810 the network was operated by "Corpo Telegráfico", the first Portuguese military Signal Corps.

Spain was spanned by an extensive semaphore telegraph network in the 1840s and 1850s [25] . The three main semaphore lines radiated from Madrid [25] [26] . The first ran north to Irun on the Atlantic coast at the French border. The second ran west to the Mediterranean, then north along the coast through Barcelona to the French border. The third ran south to Cadiz on the Atlantic coast. These lines served many other Spanish cities, including: Aranjuez, Badajoz, Burgos, Castellon, Ciudad Real, Córdoba, Cuenca, Gerona, Pamplona, San Sebastian, Seville, Tarancon, Taragona, Toledo, Valladolid, Valencia, Vitoria and Zaragoza [26] .

In Canada, Prince Edward, Duke of Kent established the first semaphore line in North America. In operation by 1800, it ran between the city of Halifax and the town of Annapolis in Nova Scotia, and across the Bay of Fundy to Saint John and Fredericton in New Brunswick. In addition to providing information on approaching ships, the Duke used the system to relay military commands, especially as they related to troop discipline. The Duke had envisioned the line reaching as far as the British garrison at Quebec City; however, the many hills and coastal fog meant the towers needed to be placed relatively close together to ensure visibility. The required labour to build and continually man so many stations taxed the already stretched-thin British military and there is doubt the New Brunswick line was ever in operation. With the exception of the towers around Halifax harbour, the system was abandoned shortly after the Duke's departure in August 1800. [27] [28]

The Semaphore Tower at Khatirbazar, Andul in Howrah district of West Bengal. Semaphore Tower at Khatirbazar, Andul.jpg
The Semaphore Tower at Khatirbazar, Andul in Howrah district of West Bengal.

In 1801, the Danish post office installed a semaphore line across the Great Belt strait, Storebæltstelegrafen, between islands Funen and Zealand with stations at Nyborg on Funen, on the small island Sprogø in the middle of the strait, and at Korsør on Zealand. It was in use until 1865. [29]

The Kingdom of Prussia began with a line 750 kilometres (470 mi) long between Berlin and Coblenz in 1833, and in Russia, Tsar Nicolas I inaugurated a line between Moscow and Warsaw of 1,200 kilometres (750 mi) length in 1833; it needed 220 stations manned by 1,320 operators.

Ta' Kenuna Tower, a semaphore tower in Nadur, Gozo, Malta, built by the British in 1848 Sudika Nadur Ta' Kenuna.jpg
Ta' Kenuna Tower, a semaphore tower in Nadur, Gozo, Malta, built by the British in 1848

The British military authorities began to consider installing a semaphore line in Malta in the early 1840s. Initially, it was planned that semaphore stations be established on the bell towers and domes of the island's churches, but the religious authorities rejected the proposal. Due to this, in 1848 new semaphore towers were constructed at Għargħur and Għaxaq on the main island, and another was built at Ta' Kenuna on Gozo. Further stations were established at the Governor's Palace, Selmun Palace and the Giordan Lighthouse. Each station was manned by the Royal Engineers. [30]

In the United States the first optical telegraph was built by Jonathan Grout in 1804 but ceased operation in 1807. A 104 kilometres (65 mi) line connecting Martha's Vineyard with Boston, its purpose was to transmit news about shipping. An optical telegraph system linking Philadelphia and the mouth of the Delaware Bay was in place by 1809 and had a similar purpose; a second line to New York City was operational by 1834, when its Philadelphia terminus was moved to the tower of the Merchants Exchange. One of the principal hills in San Francisco, California is also named "Telegraph Hill", after the semaphore telegraph which was established there in 1849 to signal the arrival of ships into San Francisco Bay.

The semaphores were successful enough that Samuel Morse failed to sell the electrical telegraph to the French government; however, France finally committed to replace semaphores with electric telegraphs in 1846. Electric telegraphs are both more private and almost completely unaffected by weather; they also work at night. Many contemporaries predicted the failure of electric telegraphs because "they are so easy to cut." [31] The last stationary semaphore link in regular service was in Sweden, connecting an island with a mainland telegraph line. It went out of service in 1880.

A cartoon strip of "Monsieur Pencil" (1831) by Rodolphe Topffer Telegraphe Chappe par Topffer.jpg
A cartoon strip of "Monsieur Pencil" (1831) by Rodolphe Töpffer

The Chappe telegraph appeared in contemporary fiction and comic strips. In "Mister Pencil" (1831), comic strip by Rodolphe Töpffer, a dog fallen on a Chappe telegraph's arm and its master attempting to help provoke an international crisis by involuntarily transmitting disturbing messages. In "Lucien Leuwen" (1834), Stendhal pictures a power struggle between Lucien Leuwen and the prefect M. de Séranville with the telegraph's director M. Lamorte. In Chapter 60 ("The Telegraph") of Alexandre Dumas' The Count of Monte Cristo (1844), the title character describes with fascination the semaphore line's moving arms. "I had at times seen rise at the end of a road, on a hillock and in the bright light of the sun, these black folding arms looking like the legs of an immense beetle." [32] He later bribes a semaphore operator to relay a false message in order to manipulate the French financial market. Dumas also describes in details the functioning of a Chappe telegraph line. In Hector Malot's novel Romain Kalbris (1869), one of the characters, a girl named Dielette, describes her home in Paris as "...next to a church near which there was a clock tower. On top of the tower there were two large black arms, moving all day this way and that. [I was told later] that this was Saint-Eustache church and that these large black arms were a telegraph." [33] The system was referenced in later works such as C. S. Forester's Hornblower and the Hotspur (1962), where the destruction of a French semaphore tower and a shore battery is a key plot point. A similar event is also the focus of the seventh episode of the television series. Interference with the French semaphore system is also an important plot element in Ramage's Signal by Dudley Pope. In the young adult fiction book Death Cloud by Andy Lane (2010), Mycroft Holmes tells 14-year-old Sherlock Holmes about semaphore stations, commenting about his school beforehand, saying "All the Latin a boy can cram into his skull, but nothing of practical use."

Fictional versions of the telegraph also appear in literature. In the alternative history novel, Lest Darkness Fall (1939), by L. Sprague de Camp, the protagonist, a twentieth century man who time travels into Dark Age Rome, develops a semaphore system to warn of invasion. To make it practical, he also invents the telescope. Pavane (1968), an alternate history novel by Keith Roberts, features a society where long distance communication is by a network of semaphores operated by the powerful Guild of Signallers. Terry Pratchett's Discworld novels (from The Fifth Elephant , 1999, onwards) describe a system of eight-shutter semaphore towers, known as Clacks, which occupy a similar role to that of the Internet. Using advanced clack coding, it is possible not only to send very fast telegrams, but also to encode pictures and send them long-distance, and shopping and banking via the clacks is also mentioned. In David Weber's Safehold series (2007), a worldwide semaphore system is used by the Church to help them maintain their dominion over the world. In Alastair Reynolds' Terminal World (2010), the distant-future terrain is criss-crossed with semaphore lines relaying information between the one remaining city, Spearpoint, outlying communities and the airborne community Swarm.

See also

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In telecommunications and computer networks, multiplexing is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910.

Optical communication communication at a distance using light to carry 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.

Heliograph communication device

A heliograph is a wireless telegraph that signals by flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military, survey and forest protection work. Heliographs were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975.

Flag signals can mean any of various methods of using flags or pennants to send signals. Flags may have individual significance as signals, or two or more flags may be manipulated so that their relative positions convey symbols. Flag signals allowed communication at a distance before the invention of radio and are still used especially in connection with ships.

History of telecommunication aspect of history relating to telecommunications

The history of telecommunication began with the use of smoke signals and drums in Africa, the Americas and parts of Asia. 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.

Deal Timeball

The Deal Timeball is a Victorian maritime Greenwich Mean Time signal located on the roof of a waterfront four-storey tower in the coastal town of Deal, in Kent, England. It was established in 1855 by the Astronomer Royal George Biddell Airy in collaboration with Charles V. Walker, superintendent of telegraphs for the South Eastern Railway Company. It was built by the Lambeth firm of engineers Maudslay and Field. The time ball, which, like the Greenwich time ball, fell at 1 pm precisely, and was triggered by an electric signal directly from the Royal Observatory.

Telegraph is any apparatus or process to convey messages over long distances with no intermediary messenger.

Procedure signs or prosigns are shorthand signals used in radio telegraphy procedures, for the purpose of simplifying and standardizing communications related to radio operating issues among two or more radio operators. They are distinct from general Morse code abbreviations, which consist mainly of brevity codes that convey messages to other parties with greater speed and accuracy.

Ta Kenuna Tower

Ta' Kenuna Tower is a semaphore tower on the cliffs near Nadur on the island of Gozo, Malta. It was built by the British in 1848, as one of three semaphore towers in Malta. The tower was restored in 2005, and it now houses as a beacon to warn ships of their proximity to land, as well as a number of communication antennas.

A signal station is a form of Aids to Navigation that is defined by the IHO simply as "A signal station is a place on shore from which signals are made to ships at sea". While this broad definition would include coastal radio stations and fog signal stations, the term is most often used for shore installation that use visual signals to communicate with ships at sea.

The following outline is provided as an overview of and topical guide to telecommunication:

Flag semaphore telegraphy system conveying information at a distance by means of visual signals

Flag semaphore is the telegraphy system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used in the maritime world in the 19th century. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or using lighted wands instead of flags, at night.

Prussian semaphore system

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.

Telex switched network of teleprinters

The telex network was a public switched network of teleprinters similar to a telephone network, for the purposes of sending text-based messages. Telex was a major method of sending written messages electronically between businesses in the post-World War II period. Its usage went into decline as the fax machine grew in popularity in the 1980s.

Fort de Valros

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.

References

Citations
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Bibliography

Further reading