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#REDIRECT [[Semaphore]] |
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{{inuse}} |
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[[Image:OptischerTelegraf.jpg|right|220px|thumb|Optical telegraph of Claude Chappe on the [[Litermont]] near [[Nalbach]], [[Germany]].]] |
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[[Image:Semaphore_Papa.svg|right |thumb|180px|Diagram of person holding 2 semaphore flags as letter "P"]] |
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[[Image:Tour du telegraphe Chappe Saverne 02.JPG|thumb|right|A Chappe semaphore tower near [[Saverne]], [[France]]]] |
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[[Image:Chappe telegraf.jpg|thumb|right|A Chappe semaphore telegraph at [[Louvre]], [[France]]]] |
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{{otheruses}} |
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A '''semaphore''' or '''optical telegraph''' is an apparatus for conveying information by means of visual signals, with towers with pivoting blades or paddles, shutters, in a matrix, or hand-held flags etc. Information is encoded by the position of the mechanical elements; it is read when the blade or flag is in a fixed position. In modern usage it refers to a system of signaling using two handheld flags (''see diagram below''). Other forms of optical telegraphy include [[ship flags]], [[Aldis lamp]]s, and [[Heliograph]]s. |
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Semaphore lines were the prototype of the [[electrical telegraph]]. They were faster than [[post rider]]s for bringing a message over long distances, but far more expensive and less private than the electrical telegraph lines which would replace them. The distance that an optical telegraph can bridge is limited by geography and weather, thus in practical use, most optical telegraphs used lines of relay stations to bridge longer distances. |
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==History== |
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Optical telegraphy dates from ancient times, in the form of torches (as used by ancient Greeks) and [[smoke signals]]. |
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The first modern form of semaphores is due to the English scientist [[Robert Hooke]], who first gave a vivid and comprehensive outline of visual telegraphy to the [[Royal Society]] in a submission dated [[1684]]; in it he outlined many practical details, but his system was never put into practice<ref>http://mysite.du.edu/~jcalvert/railway/semaphor/semhist.htm</ref> |
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<ref>http://www.ilt.columbia.edu/projects/bluetelephone/html/part2.html</ref>. |
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The system was motivated by military concerns, following the recent [[Battle of Vienna]] in [[1683]]. |
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Over a hundred years later a French engineer, [[Claude Chappe]] and his brothers took up the challenge again and succeeded in covering [[France]] with a network of 556 stations stretching a total distance of 4,800 kilometres. It was used for military and national communications until the 1850s. |
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Many national services adopted signaling systems different from the Chappe system. For example, [[UK|Britain]] 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. |
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===France=== |
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There was a desperate need for swift and reliable communications in France during the period of 1790-1795. It was the height of the [[French revolution]], and France was surrounded by the allied forces of [[England]], [[The Netherlands]], [[Prussia]], [[Austria]], and [[Spain]]. The cities of [[Marseilles]] and [[Lyon]] were in revolt, and the [[History of the Royal Navy#Wars with France, 1690–1815|English Fleet]] held [[Toulon]]. In this situation the only advantage France held was the lack of cooperation between the allied forces due to their inadequate lines of communications. |
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The Chappe brothers in the summer of 1790 set about to devise a system of communication that would allow the central government to receive intelligence and to transmit orders in the shortest possible time. On [[March 2]], [[1791]] at 11 A.M., Chappe and his brother sent the message “si vous reussissez, vous serez bientôt couvert de gloire” (If you succeed, you will soon bask in glory) between Brulon and Parce, a distance of ten miles (16 km). The first means used a combination of black and white panels, clocks, telescopes, and codebooks to send their message. |
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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 [[Chouan|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. 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. |
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[[Image:Claude Chappe.jpg|thumb|right|[[Claude Chappe]]]] |
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Paris to [[Strasbourg]] with 50 stations was the next line and others followed soon after. 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 the system was funded by the proceeds of its own lottery did costs come under control. |
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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: |
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'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.' |
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====Relative costs==== |
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The semaphore system was cleverly designed, and provided a strategic advantage for France in a difficult time. However, it was almost 30 times more expensive per message than the electric telegraph. Here's a brief breakdown using (inflation-adjusted) $US: |
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Semaphore line, 120 miles (Paris to Lille) |
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* 15 towers ($1,500,000) |
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* At least 15 full-time operators ($450,000/year). |
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* Operates at most ten hours a day. |
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* Sends roughly 2 words per minute (1 symbol per minute, at 2 symbols per phrase, using the efficient directors' codebook). |
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* Cost to send one word one mile (1.6 km), at 10% markup: $0.0114 |
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Electric Telegraph line, {{convert|120|mi|km|-1}} |
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* At least six full-time operators ($180,000/year) |
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* Poles, right-of-way, wires, installation: $15,000/mile, ($1,800,000) |
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* Operates 24 hours a day. |
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* Sends 15 words per minute (includes breaks for the operators). |
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* Cost to send one word one mile (1.6 km), at 10% markup: $0.0003809 |
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====Description==== |
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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 black movable wooden arms, the position of which indicated alphabetic letters. With counterweights on the arms, the Chappe system was controlled by only two handles and was mechanically simple and reasonably rugged. Each of the two arms showed seven positions, and the cross bar connecting the two arms had four different angles, for a total of 196 symbols (7x7x4). Night operation with lamps on the arms was unsuccessful. |
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To speed 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. |
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===Sweden=== |
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At the same time as Chappe, the Swede [[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]]. |
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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 from one another. |
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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. |
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===England=== |
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[[Lord George Murray (bishop)|Lord George Murray]], stimulated by reports of the Chappe semaphore, proposed a system of visual telegraphy to the [[British Admiralty]]. He employed large wooden boards on his towers with six large holes which could be closed by shutters. Starting in 1795, chains of shutter telegraph stations were built along these routes: |
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====London - Deal and Sheerness==== |
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[[Admiralty#The buildings|Admiralty]] ([[London]]), West Square [[Southwark]], [[New Cross]], [[Shooter's Hill]], Swanscombe, [[Higham, Kent|Gad's Hill]], Callum Hill, Beacon Hill (Faversham, branch point), Shottenden, Barham Downs, Betteshanger, [[Deal]]. |
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(branch) Beacon Hill (Faversham), Tonge, Barrow Hill, [[Sheerness]]. |
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====London - Great Yarmouth==== |
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Admiralty (London), [[Hampstead Heath]] (Telegraph Hill), Woodcock Hill, [[St Albans]], [[Dunstable Downs]], Lilley Hoo, [[Baldock]], [[Royston, Hertfordshire|Royston]], Gogmagog Hills, [[Newmarket]] (Side Hill), Icklingham, [[Barnham, Suffolk|Barnham]], [[East Harling]], [[Carleton Rode]], [[Wreningham]], [[Norwich]], [[Strumpshaw]], [[Great Yarmouth]]. |
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====London - Portsmouth and Plymouth==== |
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Admiralty (London), [[Chelsea Royal Hospital]], [[Putney Heath]], Cabbage Hill, Netley Heath, [[Hascombe]], [[Blackdown, Sussex|Blackdown]], [[Harting|Beacon Hill]] (branch point), [[Portsdown Hill]], [[Portsmouth]] (Southsea Common). |
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(branch) [[Harting|Beacon Hill]], [[Chalton, Hampshire|Chalton]], [[Wickham]], Town Hill, Toot Hill, [[Bramshaw]], Pistle Down, [[Chalbury]], [[Blandford Camp|Blandford racecourse]], [[Belchalwell]], Nettlecombe Tout, High Stoy, Toller Down, Lamberts Castle, Dalwood Common, St Cyrus, Rockbeare, Gt Halden, South Knighton, Marley, Lee, [[Saltram]], [[Plymouth]]. |
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The London to Portsmouth shutter telegraph chain was replaced by a chain of semaphore stations which was operational from 1822 to 1847. It did not use the same locations as the shutter chain, but followed almost the same route with 15 stations - |
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Admiralty (London), Chelsea, Putney Heath, Coombe Warren ([[Kingston upon Thames]]), [[Claygate|Coopers Hill]], [[Chatley Heath]], Pewley Hill ([[Guildford]]), Bannicle Hill ([[Godalming]]), Haste Hill ([[Haslemere]]), Holder Hill ([[Midhurst]]), Beacon Hill (Harting), Compton Down (Compton), Camp Down (Portsdown Hill), [[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. |
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A semaphore based successor for the London to Plymouth shutter telegraph chain, branching much closer to London, at Chatley Heath in [[Surrey]], was started but abandoned before completion. |
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Many of the prominences on which the towers were built 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. |
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===Other countries=== |
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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 [[post office|postal authorities]] operated the semaphore lines. |
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The [[Kingdom of Prussia]] began with a line 750 kilometres long between [[Berlin]] and [[Coblenz]] in 1833, and in [[Russia]], [[Nicholas I of Russia|Tsar Nicolas I]] inaugurated the line between [[Moscow]] and [[Warsaw]] (1200 km) in 1833; this needed 220 stations manned by 1320 operators. |
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In the [[United States]] the first optical telegraph was built by [[Jonathan Grout]]. It was a 104 kilometre line connecting [[Martha's Vineyard]] with [[Boston]], and its purpose was to transmit news about shipping. One of the principal hills in [[San Francisco, California]] is also named "[[Telegraph Hill]]", after the semaphore telegraph which was established there in the 1850s to signal the arrival of ships into [[San Francisco Bay]]. |
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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. Note that electric telegraphs are both more private and unaffected by weather. Many contemporaries predicted the failure of electric telegraphs because "they are so easy to cut." 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. |
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In [[Ireland]], [[Richard Lovell Edgeworth]] (1744-1817) proposed a telegraph there when a French invasion was anticipated in 1794, and again in 1796, however the proposal was not implemented. |
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==References in popular culture== |
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An episode in [[Hornblower and the Hotspur]] (one of [[C. S. Forester]]'s [[Horatio Hornblower]] books) involves the destruction of a Napoleonic semaphore station on the coast of [[France]]. This event is filmed in the British TV movie "Loyalty", the seventh episode in the 8-episode series of Hornblower movies |
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One of [[Dudley Pope]]'s [[Lord Ramage]] books, ''[[Ramage's Signal]]'', has Ramage's crew seize a Napoleonic semaphore station to send a signal directing a French convoy into a trap. The semaphore, however, is depicted as using flapping panels or shutters rather than the arms of the Chappe system. |
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The [[Clacks (Discworld)|Clacks]] system in [[Terry Pratchett]]'s [[Discworld]] universe is very similar to the Chappe semaphore, and is probably based upon it. In the books, the Clacks system takes the place of the real world [[Internet]] and [[telephone]] network. |
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In Alexandre Dumas' ''[[The Count of Monte Cristo]]'' the antihero uses France's optical telegraph system to trick one of his adversaries into going bankrupt. |
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An episode of ''[[Monty Python's Flying Circus]]'' depicts a supposed dramatic production of ''[[Wuthering Heights]]'' in flag semaphore. |
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In the same episode of [[Monty Python's Flying Circus]], they use an aldus lamp in a parody of [[Shakespeare]]'s [[Julius Caesar]], with Caesar signaling, "E tu brute!" |
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An episode of ''[[Due South]]'' features the use of semaphore communication between two [[Royal Canadian Mounted Police]] (RCMP) officers during a hostage crisis. They did not use flags. |
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In [[Jack Vance]]'s SF novel ''The Blue World'', islands in the ocean communicate with "wink machines", which display binary arrays of panels, possibly derived from the system Chappe decided was less effective. |
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[[Keith Roberts]]' ''[[Pavane (novel)|Pavane]]'' describes an extensive network of semaphores in Britain, operated by a powerful 'Guild of Signalers' who have a monopoly on communication; the second "measure" of the book is the story of the training and experience of a "signaller". |
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[[Ernest Hemingway]]'s ''[[The Sun Also Rises]]'' references a statue in Paris where "the inventor of the semaphore is engaged in doing same" near the Boulevard Raspail. |
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In the book ''[[Winter Holiday (novel)|Winter Holiday]]'' by [[Arthur Ransome]], Nancy sends secret messages to the other children by means of a picture in which the people's arm positions represent semaphore letters. |
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In a strip, the [[webcomic]] ''[[Sam and Fuzzy]]'' portrays one of the two titular characters, Fuzzy, using flag-based semaphore to convey a message he has been expressly (and legally) forbidden to repeat. |
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The [[Beatles]]' album cover ''[[Help! (album)|Help!]]'' (1965), according to photographer Robert Freeman, was originally going to show the [[Beatles]] signaling the word HELP in semaphore. However, if read according to the code, George signals an "N" or maybe an "R" or "S", John a "U", Paul a "J", and Ringo a "D", "V", or "Cancel". The images on the US album are out of order, and all of the pictures are mirror-reversed. In the UK order, and reversed, the message appears to spell "LPUS." Freeman has stated that the letters "H-E-L-P" did not look good, graphically. Apparently "LPUS" ("help us") was used as a better-looking substitute (see Freeman, ''The Beatles: a Private View'', p.62). |
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The song "The Road Leads Where It's Led" by [[The Secret Machines]] from their debut album, [[Now Here is Nowhere]] references semaphore. |
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In the movie "[[The Last Detail]]" starring Jack Nicholson and Randy Quaid, Nicholson plays a signalman in the US Navy who teaches semaphore to Quaid while escorting him to military prison. Quaid signals: "Bravo Yankee, Bravo Yankee, end of message" before attempting an escape. |
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The [[peace symbol]] is a combination of the semaphoric letters N and D, standing for "nuclear disarmament." |
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In the [[April 1 RFC]] of 2007, the [[IETF]] proposed a way to transmit Internet traffic via semaphores, thus connecting the "[[Victorian Internet]]" and the current-day one. <!-- (link in external link section. do not add.) --> |
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== See also == |
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* [[Aldis lamp]] |
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* [[Childs Hill]] for an example of a Telegraph Hill |
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* [[Heliograph]] |
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* [[Railway signalling]] |
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* [[Signal lamp]] |
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* [[Telegraph Hill]] |
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* [[Semaphore Flag Signaling System]] |
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== References == |
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Crowley, David and Heyer, Paul (ed) (2003) 'Chapter 17: The optical telegraph' ''Communication in History: Technology, Culture and Society'' (Fourth Edition) Allyn and Bacon, Boston pp. 123-125 |
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==Further reading== |
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* ''The Old Telegraphs'', Geoffrey Wilson, Phillimore & Co Ltd 1976 ISBN 0900592796 |
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* ''Faster Than The Wind, The Liverpool to Holyhead Telegraph'', Frank Large, an avid publication ISBN 0952102099 |
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==External links== |
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*[http://people.deas.harvard.edu/~jones/cscie129/images/history/chappe.html Chappe's semaphore] (an illustrated history of optical telegraphy) |
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*[http://www.royal-signals.org.uk/Datasheets/Telegraph%20.php The Royal Signals Org.UK Datasheets] |
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*[http://www.vauxhallandkennington.org.uk/telegraph.shtml Webpage including a map of England's telegraph chains] |
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* RFC 4824 The Transmission of IP Datagrams over the Semaphore Flag Signaling System (SFSS) |
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{{writing systems}} |
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[[Category:Early telecommunications]] |
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[[Category:Latin alphabet representations]] |
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[[Category:Scoutcraft]] |
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[[cs:Semafor (abeceda)]] |
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[[da:Optisk telegraf]] |
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[[de:Semaphor]] |
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[[es:Telégrafo óptico]] |
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[[fr:Sémaphore (communication)]] |
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[[id:Semafor]] |
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[[he:סמפור (איתות)]] |
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[[nl:Semafoor (communicatie)]] |
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[[ja:腕木通信]] |
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[[no:Optisk telegraf]] |
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[[pl:Alfabet semaforowy]] |
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[[ru:Оптический телеграф]] |
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[[fi:Optinen lennätin]] |
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[[sv:Optisk telegraf]] |
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[[vi:Semaphore]] |
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[[zh:旗語]] |
Revision as of 19:13, 30 December 2007
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