Editing Electrical telegraph (section)

== History ==
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=== Precursors ===
{{main|Telegraphy}}
Prior to the electric telegraph, visual systems were used, including [[Beacon|beacons]], [[smoke signal]]s, [[flag semaphore]], and [[optical telegraph]]s for visual signals to communicate over distances of land.<ref>{{Cite book |last=Williams |first=Raymond |title=Television: Technology and Cultural Form |publisher=Wesleyan University Press |year=1974 |isbn=0819562599 |location=Hanover, NH |chapter=The Technology and the Society}}</ref> 

An auditory predecessor was West African [[Talking drum|talking drums]]. In the 19th century, [[Yoruba people|Yoruba]] drummers used talking drums to mimic human [[Tone (linguistics)|tonal]] [[Yoruba language|language]]<ref>{{cite book |last=Chen |first=Matthew Y. |year=2000 |title=Tone Sandhi: patterns across Chinese dialects |publisher=Cambridge University Press |isbn=9780521033404}}</ref><ref>{{cite book |last=Odden |first=David |year=1995 |chapter=Tone: African languages |editor=J. Goldsmith |title=Handbook of Phonological Theory |location=Oxford |publisher=Basil Blackwell}}</ref> to communicate complex messages – usually regarding news of birth, ceremonies, and military conflict – over 4–5 mile distances.<ref>{{cite book |last=Ong |first=Walter |title=Interfaces of the Word: Studies in the Evolution of Consciousness and Culture |year=1977 |page=101}}</ref>

Possibly the earliest design and conceptualization for a telegraph system was 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 was largely motivated by military concerns, following the Battle of Vienna in 1683.<ref>{{cite web|url=http://mysite.du.edu/~jcalvert/railway/semaphor/semhist.htm |title=The Origin of the Railway Semaphore |publisher=Mysite.du.edu |access-date=2013-06-17}}</ref><ref>{{cite web |url=http://www.ilt.columbia.edu/projects/bluetelephone/html/part2.html |title=History of the Telephone part2 |publisher=Ilt.columbia.edu |access-date=2013-06-17 |archive-url=https://web.archive.org/web/20121128120005/http://www.ilt.columbia.edu/projects/bluetelephone/html/part2.html |archive-date=2012-11-28 |url-status=dead }}</ref>

The first official optical telegraph was invented in France in the 18th century by [[Claude Chappe]] and his brothers. The Chappe system would stretch nearly 5,000 km with 556 stations and was used until the 1850s.<ref>{{Cite web |title=La fin des lignes de télégraphie Chappe |url=http://www.telegraphe-chappe.com/chappe/fin.html |access-date=2025-02-21 |website=www.telegraphe-chappe.com}}</ref>

===Early work===
[[File:Soemmerring 1810 telegraph overview.jpg|thumb|Sömmering's electric telegraph in 1809]]
From [[History of electrical engineering|early studies of electricity]], electrical phenomena were known to travel with great speed, and many experimenters worked on the application of electricity to [[communication]]s at a distance. All the known effects of electricity{{snd}}such as [[electric spark|sparks]], [[electrostatic attraction]], [[chemical change]]s, [[electric shock]]s, and later [[electromagnetism]]{{snd}}were applied to the problems of detecting controlled transmissions of electricity at various distances.<ref>Fahie</ref>
	
In 1753, an anonymous writer in the ''[[Scots Magazine]]'' suggested an electrostatic telegraph. Using one wire for each letter of the alphabet, a message could be transmitted by connecting the wire terminals in turn to an electrostatic machine, and observing the deflection of [[pith]] balls at the far end.<ref>{{cite book |last=Marland |first=A. E. |title=Early Electrical Communication |publisher=Abelard-Schuman |date=1964 |pages=17–19}}{{LCCN|6420875}}</ref> The writer has never been positively identified, but the letter was signed C.M. and posted from [[Renfrew]] leading to a Charles Marshall of Renfrew being suggested.<ref>Holzmann & Pehrson, p. 203</ref> Telegraphs employing electrostatic attraction were the basis of early experiments in electrical telegraphy in Europe, but were abandoned as being impractical and were never developed into a useful communication system.<ref>{{Citation |title=Electromagnetic Telegraph – Invented by Baron Pavel Schilling |url=http://www.edubilla.com/invention/electrical-telegraph/}}</ref>

In 1774, [[Georges-Louis Le Sage]] realised an early electric telegraph. The telegraph had a separate wire for each of the 26 letters of the [[alphabet]] and its range was only between two rooms of his home.<ref>Prevost, 1805, pp. 176–178</ref>

In 1800, [[Alessandro Volta]] invented the [[voltaic pile]], providing a [[continuous current]] of [[electricity]] for experimentation. This became a source of a low-voltage current that could be used to produce more distinct effects, and which was far less limited than the momentary discharge of an [[electrostatic generator|electrostatic machine]], which with [[Leyden jar]]s were the only previously known human-made sources of electricity.
	 	
Another very early experiment in electrical telegraphy was an "electrochemical telegraph" created by the [[Germans|German]] [[physician]], anatomist and inventor [[Samuel Thomas von Sömmering]] in 1809, based on an earlier 1804 design by Spanish [[polymath]] and scientist [[Francisco Salva Campillo]].{{sfn|Jones|1999}} Both their designs employed multiple wires (up to 35) to represent almost all Latin letters and numerals. Thus, messages could be conveyed electrically up to a few kilometers (in von Sömmering's design), with each of the telegraph receiver's wires immersed in a separate glass tube of acid. An electric current was sequentially applied by the sender through the various wires representing each letter of a message; at the recipient's end, the currents electrolysed the acid in the tubes in sequence, releasing streams of hydrogen bubbles next to each associated letter or numeral. The telegraph receiver's operator would watch the bubbles and could then record the transmitted message.{{sfn|Jones|1999}} This is in contrast to later telegraphs that used a single wire (with ground return).
	 	
[[Hans Christian Ørsted]] discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle. In the same year [[Johann Schweigger]] invented the [[galvanometer]], with a coil of wire around a compass, that could be used as a sensitive indicator for an electric current.<ref>M. (10 December 2014). Schweigger Multiplier – 1820. Retrieved 7 February 2018, from https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/museum/schweigger-multiplier</ref> Also that year, [[André-Marie Ampère]] suggested that telegraphy could be achieved by placing small magnets under the ends of a set of wires, one pair of wires for each letter of the alphabet. He was apparently unaware of Schweigger's invention at the time, which would have made his system much more sensitive. In 1825, [[Peter Barlow (mathematician)|Peter Barlow]] tried Ampère's idea but only got it to work over {{convert|200|ft|m}} and declared it impractical. In 1830 [[William Ritchie (physicist)|William Ritchie]] improved on Ampère's design by placing the magnetic needles inside a coil of wire connected to each pair of conductors. He successfully demonstrated it, showing the feasibility of the electromagnetic telegraph, but only within a lecture hall.<ref>Fahie, pp. 302–306</ref>
	 	
In 1825, [[William Sturgeon]] invented the [[electromagnet]], with a single winding of uninsulated wire on a piece of varnished [[iron]], which increased the magnetic force produced by electric current. [[Joseph Henry]] improved it in 1828 by placing several windings of insulated wire around the bar, creating a much more powerful electromagnet which could operate a telegraph through the high resistance of long telegraph wires.<ref>{{cite book |title=Technology and Society |author=R. V. G. Menon |publisher=Dorling Kindersley |location=India |year=2011}}</ref> During his tenure at [[The Albany Academy]] from 1826 to 1832, Henry first demonstrated the theory of the 'magnetic telegraph' by ringing a bell through {{convert|1|mi|km|adj=on|spell=in}} of wire strung around the room in 1831.<ref>{{cite book |last=Henry Pitt Phelps |title=The Albany Hand-book: A Strangers' Guide and Residents' Manual |url=https://archive.org/details/albanyhandbook00phel |year=1884 |publisher=Brandow & Barton |location=Albany |page=[https://archive.org/details/albanyhandbook00phel/page/6 6]}}</ref>

In 1835, [[Joseph Henry]] and [[Edward Davy]] independently invented the mercury dipping [[relay|electrical relay]], in which a magnetic needle is dipped into a pot of mercury when an electric current passes through the surrounding coil.{{sfn|Gibberd|1966}}<ref>{{cite web |url=http://www.si.edu/archives/ihd/jhp/joseph20.htm |title=Joseph Henry: Inventor of the Telegraph? Smithsonian Institution |access-date=29 June 2006 |archive-url=https://web.archive.org/web/20060626163000/http://www.si.edu/archives/ihd/jhp/joseph20.htm <!-- Bot retrieved archive --> |archive-date=26 June 2006}}</ref><ref>{{cite book |title=Joseph Henry: His Life and Work |url=https://archive.org/details/josephhenryhisli0000coul |url-access=registration |author=Thomas Coulson |publisher=Princeton University Press |location=Princeton |year=1950}}</ref> In 1837, Davy invented the much more practical metallic make-and-break relay which became the relay of choice in telegraph systems and a key component for periodically renewing weak signals.<ref>{{cite book |first1=Donald |last1=McDonald |first2=Leslie B. |last2=Hunt |title=A History of Platinum and its Allied Metals |date=January 1982 |page=306 |publisher=Johnson Matthey Plc |isbn=0905118839}}</ref> Davy demonstrated his telegraph system in [[Regent's Park]] in 1837 and was granted a patent on 4 July 1838.<ref name=bsp>{{cite web |url=http://www.asap.unimelb.edu.au/bsparcs/other/iee_davy.htm |title=Edward Davy |publisher=Australian Science Archives Project |access-date=7 June 2012}}</ref> Davy also invented a printing telegraph which used the electric current from the telegraph signal to mark a ribbon of calico infused with [[potassium iodide]] and [[calcium hypochlorite]].{{sfn|Kieve|1973|pp=23–24}}

===First working systems===
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[[File:Dial of Ronalds' electric telegraph.jpg|thumb|Revolving alphanumeric dial created by [[Francis Ronalds]] as part of his electric telegraph (1816)]]
The first working telegraph was built by the English inventor [[Francis Ronalds]] in 1816 and used static electricity.<ref>{{Cite book |title=Pioneers of Electrical Communication |url=https://archive.org/details/b29977101 |last=Appleyard |first=R. |publisher=Macmillan |year=1930}}</ref> At the family home on [[Kelmscott House|Hammersmith Mall]], he set up a complete subterranean system in a {{convert|175|yd|m|adj=on}} long trench as well as an {{convert|8|mi|km|spell=in|adj=on}} long overhead telegraph. The lines were connected at both ends to revolving dials marked with the letters of the alphabet and electrical impulses sent along the wire were used to transmit messages. Offering his invention to the [[British Admiralty|Admiralty]] in July 1816, it was rejected as "wholly unnecessary".<ref>{{Cite journal |last=Ronalds |first=B.F. |date=2016 |title=Sir Francis Ronalds and the Electric Telegraph |journal=International Journal for the History of Engineering & Technology |volume=86 |pages=42–55 |doi=10.1080/17581206.2015.1119481 |s2cid=113256632}}</ref> His account of the scheme and the possibilities of rapid global communication in ''Descriptions of an Electrical Telegraph and of some other Electrical Apparatus''<ref>{{Cite book |last=Ronalds |first=Francis |title=Descriptions of an Electrical Telegraph and of some other Electrical Apparatus |publisher=Hunter |year=1823 |location=London |url=https://archive.org/details/descriptionsane00ronagoog}}</ref> was the first published work on electric telegraphy and even described the risk of [[Submarine communications cable#Bandwidth problems|signal retardation]] due to induction.<ref>{{Cite journal |last=Ronalds |first=B.F. |date=Feb 2016 |title=The Bicentennial of Francis Ronalds's Electric Telegraph |journal=Physics Today |volume=69 |issue=2 |pages=26–31 |doi=10.1063/PT.3.3079 |bibcode=2016PhT....69b..26R |doi-access=free}}</ref> Elements of Ronalds' design were utilised in the subsequent commercialisation of the telegraph over 20 years later.<ref>{{Cite book |title=Sir Francis Ronalds: Father of the Electric Telegraph |last=Ronalds |first=B.F. |publisher=Imperial College Press |year=2016 |isbn=978-1-78326-917-4 |location=London}}</ref>

{{main|Electric telegraphy in Imperial Russia }}
[[File:Pavel Shilling.jpg|thumb|left|[[Pavel Schilling]], an early pioneer of electrical telegraphy]]
The [[Schilling telegraph]], invented by [[Baron Schilling]] von Canstatt in 1832, was an early [[needle telegraph]]. It had a transmitting device that consisted of a keyboard with 16 black-and-white keys.{{sfn|Fahie|1884|pages=307–325}} These served for switching the electric current. The receiving instrument consisted of six [[galvanometer]]s with magnetic needles, suspended from [[silk]] [[Yarn|threads]]. The two stations of Schilling's telegraph were connected by eight wires; six were connected with the galvanometers, one served for the return current and one for a signal bell. When at the starting station the operator pressed a key, the corresponding pointer was deflected at the receiving station. Different positions of black and white flags on different disks gave combinations which corresponded to the letters or numbers. Pavel Schilling subsequently improved its apparatus by reducing the number of connecting wires from eight to two.
	 	
On 21 October 1832, Schilling managed a short-distance transmission of signals between two telegraphs in different rooms of his apartment. In 1836, the British government attempted to buy the design but Schilling instead accepted overtures from [[Nicholas&nbsp;I of Russia]]. Schilling's telegraph was tested on a {{convert|5|km|mi|adj=mid|-long}} experimental underground and underwater cable, laid around the building of the main Admiralty in Saint Petersburg and was approved for a telegraph between the imperial palace at [[Peterhof Palace|Peterhof]] and the naval base at [[Kronstadt]]. However, the project was cancelled following Schilling's death in 1837.{{sfn|Huurdeman|2003|p=54}} Schilling was also one of the first to put into practice the idea of the [[binary coding|binary]] system of signal transmission.{{sfn|Fahie|1884|pages=307–325}} His work was taken over and developed by [[Moritz von Jacobi]] who invented telegraph equipment that was used by Tsar [[Alexander III of Russia|Alexander III]] to connect the Imperial palace at [[Tsarskoye Selo]] and [[Kronstadt Naval Base]].
	
In 1833, [[Carl Friedrich Gauss]], together with the physics professor [[Wilhelm Eduard Weber|Wilhelm Weber]] in [[Göttingen]], installed a {{convert|1200|m|ft|adj=mid|-long}} wire above the town's roofs. Gauss combined the [[Schweigger multiplier|Poggendorff-Schweigger multiplicator]] with his magnetometer to build a more sensitive device, the [[galvanometer]]. To change the direction of the electric current, he constructed a [[commutator (electric)|commutator]] of his own. As a result, he was able to make the distant needle move in the direction set by the commutator on the other end of the line.

[[File:Diagram of alphabet used in a 5 needle Cooke and Wheatstone Telegraph, indicating the letter G.png|thumb|left|Diagram of alphabet used in a 5-needle Cooke and Wheatstone Telegraph, indicating the letter G]]At first, Gauss and Weber used the telegraph to coordinate time, but soon they developed other signals and finally, their own alphabet. The alphabet was encoded in a binary code that was transmitted by positive or negative voltage pulses which were generated by means of moving an induction coil up and down over a permanent magnet and connecting the coil with the transmission wires by means of the commutator. The page of Gauss's laboratory notebook containing both his code and the first message transmitted, as well as a replica of the telegraph made in the 1850s under the instructions of Weber are kept in the faculty of physics at the [[University of Göttingen]], in Germany.

Gauss was convinced that this communication would be of help to his kingdom's towns. Later in the same year, instead of a [[voltaic pile]], Gauss used an [[Electromagnetic induction|induction]] pulse, enabling him to transmit seven letters a minute instead of two. The inventors and university did not have the funds to develop the telegraph on their own, but they received funding from [[Alexander von Humboldt]]. [[Carl August Steinheil]] in [[Munich]] was able to build a telegraph network within the city in 1835–1836. In 1838, Steinheil installed a telegraph along the [[Nuremberg–Fürth railway line]], built in 1835 as the first German railroad, which was the first [[earth-return telegraph]] put into service.

By 1837, [[William Fothergill Cooke]] and [[Charles Wheatstone]] had co-developed a [[Cooke and Wheatstone telegraph|telegraph system]] which used a number of needles on a board that could be moved to point to letters of the alphabet. Any number of needles could be used, depending on the number of characters it was required to code. In May 1837 they patented their system. The patent recommended five needles, which coded twenty of the alphabet's 26 letters.

[[File:Wallace Study-Telegraph.jpg|thumb|Morse key and sounder]]
[[Samuel Morse]] independently developed and patented a recording electric telegraph in 1837. Morse's assistant [[Alfred Vail]] developed an instrument that was called the register for recording the received messages. It embossed dots and dashes on a moving paper tape by a stylus which was operated by an electromagnet.{{sfn|Calvert|2008}} Morse and Vail developed the [[Morse code]] signalling [[alphabet]]. 

On 24 May 1844, Morse sent to Vail the historic first message “[[Baltimore-Washington telegraph line|WHAT HATH GOD WROUGHT]]" from the [[United States Capitol|Capitol]] in Washington to the [[B&O Railroad Museum|old Mt. Clare Depot]] in [[Baltimore]].<ref>Howe, p. 7</ref><ref>{{Citation |last=History.com Staff |title=Morse Code & the Telegraph |publisher=A+E Networks |year=2009 |url=http://www.history.com/topics/inventions/telegraph}}</ref>
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