Electrical telegraph

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

The electrical telegraph, or more commonly just telegraph, superseded optical semaphore telegraph systems, thus becoming the first form of electrical telecommunications. In a matter of decades after their creation in the 1830s, electrical telegraph networks permitted people and commerce to transmit messages across both continents and oceans almost instantly, with widespread social and economic impacts.[1]

Cooke and Wheatstone electric telegraph
Cooke and Wheatstone's five-needle, six-wire telegraph from 1837
Morse Telegraph 1837
Morse Telegraph 1837
Printing Telegraph
Hughes telegraph, an early (1855) teleprinter built by Siemens and Halske

History

Early work

Soemmerring 1810 telegraph overview
Sömmering's electric telegraph in 1809

From early studies of electricity, electrical phenomena were known to travel with great speed, and many experimenters worked on the application of electricity to communications at a distance. All the known effects of electricity - such as sparks, electrostatic attraction, chemical changes, electric shocks, and later electromagnetism - were applied to the problems of detecting controlled transmissions of electricity at various distances.

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.[2] 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.[3]

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.[4]

In 1800, Alessandro Volta invented the voltaic pile, allowing for 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 machine, which with Leyden jars were the only previously known man-made sources of electricity.

Another very early experiment in electrical telegraphy was an 'electrochemical telegraph' created by the German physician, anatomist and inventor Samuel Thomas von Sömmering in 1809, based on an earlier, less robust design of 1804 by Spanish polymath and scientist Francisco Salva Campillo.[5] 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 digit 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.[5] 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 which will deflect a compass needle. In the same year Johann Schweigger invented the galvanometer, with a coil of wire around a compass, which could be used as a sensitive indicator for an electric current. In 1821, André-Marie Ampère suggested that telegraphy could be done by a system of galvanometers, with one wire per galvanometer to indicate each letter, and said he had experimented successfully with such a system. In 1824, Peter Barlow said that such a system only worked to a distance of about 200 feet (61 m), and so was impractical.[6]

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.[7] 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 a mile (1.6 km) of wire strung around the room.[8]

In 1835, Joseph Henry and Edward Davy invented the critical electrical relay. Davy's relay used a magnetic needle which dipped into a mercury contact when an electric current passed through the surrounding coil.[9]"Joseph Henry: Inventor of the Telegraph? Smithsonian Institution". Archived from the original on 2006-06-26. Retrieved 2006-06-29.</ref>[10] Davy demonstrated his telegraph system in Regent's Park in 1837 and was granted a patent on 4 July 1838.[11] Davy also invented a printing telegraph which used the electric current from the telegraph signal to mark a ribbon of calico impregnated with potassium iodide and calcium hypochlorite.[12]

First working systems

Dial of Ronalds' electric telegraph
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.[13][14] At the family home on Hammersmith Mall, he set up a complete subterranean system in a 175 yard long trench as well as an eight mile 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 Admiralty in July 1816, it was rejected as "wholly unnecessary".[15] His account of the scheme and the possibilities of rapid global communication in Descriptions of an Electrical Telegraph and of some other Electrical Apparatus[16] was the first published work on electric telegraphy and even described the risk of signal retardation due to induction.[17] Elements of Ronalds’ design were utilised in the subsequent commercialisation of the telegraph over 20 years later.[18]

Pavel Shilling
Pavel Schilling, an early pioneer of electrical telegraphy

The telegraph invented by Baron Schilling von Canstatt in 1832 had a transmitting device which consisted of a keyboard with 16 black-and-white keys.[19] These served for switching the electric current. The receiving instrument consisted of six galvanometers with magnetic needles, suspended from silk threads. Both 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. He reduced 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 I of Russia. Schilling's telegraph was tested on a 5-kilometre-long (3.1 mi) 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 and the naval base at Kronstadt. However, the project was cancelled following Schilling's death in 1837.[20] Schilling was also one of the first to put into practice the idea of the binary system of signal transmission.

In 1833, Carl Friedrich Gauss, together with the physics professor Wilhelm Weber in Göttingen installed a 1,200-metre-long (3,900 ft) wire above the town's roofs. Gauss combined the 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 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.

At first, Gauss and Weber used the telegraph to coordinate time, but soon they developed other signals; finally, their own alphabet. The alphabet was encoded in a binary code which 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' 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 a help to his kingdom's towns. Later in the same year, instead of a Voltaic pile, Gauss used an induction pulse, enabling him to transmit seven letters a minute instead of two. The inventors and university were too poor 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 1835-6. He installed a telegraph line along the first German railroad in 1835.

Diagram of alphabet used in a 5 needle Cooke and Wheatstone Telegraph, indicating the letter G
Diagram of alphabet used in a 5 needle Cooke and Wheatstone Telegraph, indicating the letter G

The Cooke and Wheatstone telegraph, was co-developed by William Fothergill Cooke and Charles Wheatstone. In May 1837 they patented a 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. The patent recommended five needles.

Old telegraph instruments morse key and morse sounder
A Morse key and a Morse 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.[21] Morse and Vail developed the Morse code signalling alphabet. The first telegram in the United States was sent by Morse on 11 January 1838, across two miles (3 km) of wire at Speedwell Ironworks near Morristown, New Jersey, although it was only later, in 1844, that he sent the message "WHAT HATH GOD WROUGHT" over the 44 miles (71 km) from the Capitol in Washington to the old Mt. Clare Depot in Baltimore.[22][23]

Commercial telegraphy

Cooke and Wheatstone system

ABC machine
A magneto-powered ABC machine

The first commercial electrical telegraph, was the Cooke and Wheatstone telegraph. A demonstration four-needle system was installed on the Euston to Camden Town section of Robert Stephenson's London and Birmingham Railway in 1837 for signalling rope-hauling of locomotives.[24] It was rejected in favour of pneumatic whistles.[25] Cooke and Wheatstone had their first commercial success with a system installed on the Great Western Railway over the 13 miles (21 km) from Paddington station to West Drayton in 1838.[26] This was a five-needle, six-wire[25] system. This system suffered from failing insulation on the underground cables.[27][28] When the line was extended to Slough in 1843, the telegraph was converted to a one-needle, two-wire system with uninsulated wires on poles.[29] The one-needle telegraph proved highly successful on British railways, and 15,000 sets were still in use at the end of the nineteenth century. Some remained in service in the 1930s.[30] The Electric Telegraph Company, the world's first public telegraphy company was formed in 1845 by financier John Lewis Ricardo and Cooke.[31][32]

Wheatstone developed a practical alphabetical system using a magneto. Such machines stayed in use in Britain until well into the 20th century.[33]

Morse system

The first telegram. Professor Samuel Morse sending the despatch as dictated by Miss Annie Ellsworth
Professor Morse sending the message — WHAT HATH GOD WROUGHT on May 24, 1844

In 1851, a conference in Vienna of countries in the German-Austrian Telegraph Union (which included many central European countries) adopted the Morse telegraph as the system for international communications.[34] The code adopted was considerably modified from the original Morse code, and was based on a code used on Hamburg railways (Gerke, 1848).[35] A common code was a necessary step to allow direct telegraph connection between countries. With different codes, additional operators were required to translate and retransmit the message. In 1865, a conference in Paris adopted Gerke's code as the International Morse code and was henceforth the international standard. The US, however, continued to use American morse code internally for some time, hence international messages required retransmission in both directions.[36]

In the United States, the Morse/Vail telegraph was quickly deployed in the two decades following the first demonstration in 1844. The overland telegraph connected the west coast of the continent to the east coast by 24 October 1861, bringing an end to the Pony Express.[37]

Expansion

As well as the rapid expansion of the use of the telegraphs along the railways, they soon spread into the field of mass communication with the instruments being installed in post offices. The era of mass personal communication had begun. Telegraph networks were expensive to build, but financing was readily available, especially from London bankers. By 1852, National systems were in operation in major countries:[38][39]

Extent of the telegraph in 1852
Country Company or system Miles of wire ref
United States 20 companies 23,000 [40]
United Kingdom Cooke-Wheatstone company and minor companies 2,200 [41]
Prussia Siemens system 1,400
Austria Siemens system 1,000
Canada 900
France optical systems dominant 700

Although many countries had telegraph networks, there was no worldwide interconnection. Message by post was still the primary means of communication to countries outside Europe.

Worldwide postal speeds in 1852
A letter by post from London took
days to reach[42]
12 New York in the United States
13 Alexandria in Egypt
19 Constantinople in Ottoman Turkey
33 Bombay in India (west coast of India)
44 Calcutta in Bengal (east coast of India)
45 Singapore
57 Shanghai in China
73 Sydney in Australia

Telegraphic improvements

Components of the electromechanical telegraph network. Proce Wellcome V0025510
Wheatstone automated telegraph network equipment

A continuing goal in telegraphy was to reduce the cost per message by reducing hand-work, or increasing the sending rate. There were many experiments with moving pointers, and various electrical encodings. However, most systems were too complicated and unreliable. A successful expedient to reduce the cost per message was the development of telegraphese.

The first system that didn't require skilled technicians to operate, was Charles Wheatstone's ABC system in 1840 where the letters of the alphabet were arranged around a clock-face, and the signal caused a needle to indicate the letter. This early system required the receiver to be present in real time to record the message and it reached speeds of up to 15 words a minute.

In 1846, Alexander Bain patented a chemical telegraph in Edinburgh. The signal current moved an iron pen across a moving paper tape soaked in a mixture of ammonium nitrate and potassium ferrocyanide, decomposing the chemical and producing readable blue marks in Morse code. The speed of the printing telegraph was 1000 words per hour, but messages still required translation into English by live copyists. Chemical telegraphy came to an end in the US in 1851, when the Morse group defeated the Bain patent in the US District Court.[43]

For a brief period, starting with the New York-Boston line in 1848, some telegraph networks began to employ sound operators, who were trained to understand Morse code aurally. Gradually, the use of sound operators eliminated the need for telegraph receivers to include register and tape. Instead, the receiving instrument was developed into a "sounder", an electromagnet that was energized by a current and attracted a small iron lever. When the sounding key was opened or closed, the sounder lever struck an anvil. The Morse operator distinguished a dot and a dash by the short or long interval between the two clicks. The message was then written out in long-hand.[44]

Royal Earl House developed and patented a letter-printing telegraph system in 1846 which employed an alphabetic keyboard for the transmitter and automatically printed the letters on paper at the receiver,[45] and followed this up with a steam-powered version in 1852.[46] Advocates of printing telegraphy said it would eliminate Morse operators' errors. The House machine was used on four main American telegraph lines by 1852. The speed of the House machine was announced as 2600 words an hour.[47]

Clavier Baudot
A Baudot keyboard, 1884

David Edward Hughes invented the printing telegraph in 1855; it used a keyboard of 26 keys for the alphabet and a spinning type wheel that determined the letter being transmitted by the length of time that had elapsed since the previous transmission. The system allowed for automatic recording on the receiving end. The system was very stable and accurate and became accepted around the world.[48]

The next improvement was the Baudot code of 1874. French engineer Émile Baudot patented a printing telegraph in which the signals were translated automatically into typographic characters. Each character was assigned a five-bit code, mechanically interpreted from the state of five on/off switches. Operators had to maintain a steady rhythm, and the usual speed of operation was 30 words per minute.[49]

By this point reception had been automated, but the speed and accuracy of the transmission was still limited to the skill of the human operator. The first practical automated system was patented by Charles Wheatstone, the original inventor of the telegraph. The message (in Morse code) was typed onto a piece of perforated tape using a keyboard-like device called the 'Stick Punch'. The transmitter automatically ran the tape through and transmitted the message at the then exceptionally high speed of 70 words per minute.

Teleprinters

Phelps' Electro-motor Printing Telegraph
Phelps' Electro-motor Printing Telegraph from circa 1880, the last and most advanced telegraphy mechanism designed by George May Phelps
Bundesarchiv Bild 183-2008-0516-500, Fernschreibmaschine mit Telefonanschluss
A Creed Model 7 teleprinter in 1930
Teletype-IMG 7289
Teletype Model 33 ASR (Automatic Send and Receive)

An early successful teleprinter was invented by Frederick G. Creed. In Glasgow he created his first keyboard perforator, which used compressed air to punch the holes. He also created a reperforator (receiving perforator) and a printer. The reperforator punched incoming Morse signals on to paper tape and the printer decoded this tape to produce alphanumeric characters on plain paper. This was the origin of the Creed High Speed Automatic Printing System, which could run at an unprecedented 200 words per minute. His system was adopted by the Daily Mail for daily transmission of the newspaper contents.

With the invention of the teletypewriter, telegraphic encoding became fully automated. Early teletypewriters used the ITA-1 Baudot code, a five-bit code. This yielded only thirty-two codes, so it was over-defined into two "shifts", "letters" and "figures". An explicit, unshared shift code prefaced each set of letters and figures. In 1901, Baudot's code was modified by Donald Murray.

In the 1930s teleprinters were produced by Teletype in the US, Creed in Britain and Siemens in Germany.

By 1935, message routing was the last great barrier to full automation. Large telegraphy providers began to develop systems that used telephone-like rotary dialling to connect teletypewriters. These resulting system was called "Telex" (TELegraph EXchange). Telex machines first performed rotary-telephone-style pulse dialling for circuit switching, and then sent data by ITA2. This "type A" Telex routing functionally automated message routing.

The first wide-coverage Telex network was implemented in Germany during the 1930s as a network used to communicate within the government.

At the rate of 45.45 (±0.5%) baud — considered speedy at the time — up to 25 telex channels could share a single long-distance telephone channel by using voice frequency telegraphy multiplexing, making telex the least expensive method of reliable long-distance communication.

Automatic teleprinter exchange service was introduced into Canada by CPR Telegraphs and CN Telegraph in July 1957 and in 1958, Western Union started to build a Telex network in the United States.[50]

The harmonic telegraph

The most expensive aspect of a telegraph system was the installation – the laying of the wire, which was often very long. The costs would be better covered by finding a way to send more than one message at a time through the single wire, thus increasing revenue per wire. Early devices included the duplex and the quadruplex which allowed, respectively, one or two telegraph transmissions in each direction. However, an even greater number of channels was desired on the busiest lines. In the latter half of the 1800s, several inventors worked towards creating a method for doing just that, including. Charles Bourseul, Thomas Edison, Elisha Gray, and Alexander Graham Bell.

One approach was to have resonators of several different frequencies act as carriers of a modulated on-off signal. This was the harmonic telegraph, a form of frequency-division multiplexing. These various frequencies, referred to as harmonics, could then be combined into one complex signal and sent down the single wire. On the receiving end, the frequencies would be separated with a matching set of resonators.

With a set of frequencies being carried down a single wire, it was realized that the human voice itself could be transmitted electrically through the wire. This effort led to the invention of the telephone. (While the work toward packing multiple telegraph signals onto one wire led to telephony, later advances would pack multiple voice signals onto one wire by increasing the bandwidth by modulating frequencies much higher than human hearing. Eventually the bandwidth was widened much further by using laser light signals sent through fiber optic cables. Fiber optic transmission can carry 25,000 telephone signals simultaneously down a single fiber.[51])

Oceanic telegraph cables

1891 Telegraph Lines
Major telegraph lines in 1891.

Soon after the first successful telegraph systems were operational, the possibility of transmitting messages across the sea by way of submarine communications cables was first proposed. One of the primary technical challenges was to sufficiently insulate the submarine cable to prevent the current from leaking out into the water. In 1842, a Scottish surgeon William Montgomerie[52] introduced gutta-percha, the adhesive juice of the Palaquium gutta tree, to Europe. Michael Faraday and Wheatstone soon discovered the merits of gutta-percha as an insulator, and in 1845, the latter suggested that it should be employed to cover the wire which was proposed to be laid from Dover to Calais. It was tried on a wire laid across the Rhine between Deutz and Cologne. In 1849, C.V. Walker, electrician to the South Eastern Railway, submerged a two-mile wire coated with gutta-percha off the coast from Folkestone, which was tested successfully.[52]

John Watkins Brett, an engineer from Bristol, sought and obtained permission from Louis-Philippe in 1847 to establish telegraphic communication between France and England. The first undersea cable was laid in 1850, connecting the two countries and was followed by connections to Ireland and the Low Countries.

The Atlantic Telegraph Company was formed in London in 1856 to undertake to construct a commercial telegraph cable across the Atlantic Ocean. It was successfully completed on 18 July 1866 by the ship SS Great Eastern, captained by Sir James Anderson after many mishaps along the away.[53] Earlier transatlantic submarine cables installations were attempted in 1857, 1858 and 1865. The 1857 cable only operated intermittently for a few days or weeks before it failed. The study of underwater telegraph cables accelerated interest in mathematical analysis of very long transmission lines. The telegraph lines from Britain to India were connected in 1870 (those several companies combined to form the Eastern Telegraph Company in 1872).

Australia was first linked to the rest of the world in October 1872 by a submarine telegraph cable at Darwin.[54] This brought news reportage from the rest of the world.[55] The telegraph across the Pacific was completed in 1902, finally encircling the world.

From the 1850s until well into the 20th century, British submarine cable systems dominated the world system. This was set out as a formal strategic goal, which became known as the All Red Line.[56] In 1896, there were thirty cable laying ships in the world and twenty-four of them were owned by British companies. In 1892, British companies owned and operated two-thirds of the world's cables and by 1923, their share was still 42.7 percent.[57]

Cable and Wireless Company

1901 Eastern Telegraph cables
The Eastern Telegraph Company network in 1901

Cable & Wireless was a British telecommunications company that traced its origins back to the 1860s, with Sir John Pender as the founder,[58] although the name was only adopted in 1934. It was formed from successive mergers including:

  • The Falmouth, Malta, Gibraltar Telegraph Company
  • The British Indian Submarine Telegraph Company
  • The Marseilles, Algiers and Malta Telegraph Company
  • The Eastern Telegraph Company[59]
  • The Eastern Extension Australasia and China Telegraph Company
  • The Eastern and Associated Telegraph Companies[60]

Telegraphy in war

The ability to send telegrams brought obvious advantages to those conducting war. Secret messages were encoded, so interception alone would not be sufficient for the opposing side to gain an advantage. There were geographical constraints on intercepting the telegraph cables, but once radio was used, interception could be much more widespread.

Crimean war

The Crimean War was one of the first conflicts to use telegraphs and was one of the first to be documented extensively. In 1854, the government in London created a military Telegraph Detachment for the Army commanded by an officer of the Royal Engineers. It was to comprise twenty-five men from the Royal Corps of Sappers & Miners trained by the Electric Telegraph Company to construct and work the first field electric telegraph.[61]

Journalistic recording of the war was provided by William Howard Russell (writing for The Times newspaper) with photographs by Roger Fenton.[62] News from war correspondents kept the public of the nations involved in the war informed of the day-to-day events in a way that had not been possible in any previous war. After the French extended the telegraph to the coast of the Black Sea in late 1854, the news reached London in two days. When the British laid an underwater cable to the Crimean peninsula in April 1855, news reached London in a few hours. The daily news reports energised public opinion, which brought down the government and led to Lord Palmerston becoming prime minister.[63]

American Civil War

During the American Civil War the telegraph proved its value as a tactical, operational, and strategic communication medium and an important contributor to Union victory.[64] By contrast the Confederacy failed to make effective use of the South’s much smaller telegraph network. Prior to the War the telegraph systems were primarily used in the commercial sector. Government buildings were not inter-connected with telegraph lines, but relied on runners to carry messages back and forth.[65] Before the war the Government saw no need to connect lines within city limits, however, they did see the use in connections between cities. Washington D.C. being the hub of Government, it had the most connections, but there were only had a few lines running north and south out of the city.[65] It wasn't until the Civil War that the Government saw the true potential of the telegraph system. Soon after the shelling of Fort Sumter, the South cut telegraph lines running into D.C. which put the city in a state of panic for they feared an immediate southern invasion.[66][65]

Within 6 months of the start of the war, the U.S. Military Telegraph Corps (USMT) had laid approximately 300 miles of line. By war's end they had laid approximately 15,000 miles of cable, 8,000 for military and 5,000 for commercial use, and had handled approximately 6.5 million messages. The telegraph was not only important for communication within the armed forces, but also in the civilian sector, helping political leaders to maintain control over their districts.[66]

Even before the war, the American Telegraph Company censored suspect messages informally to block aid to the secession movement. During the war, Secretary of War, Simon Cameron, and later Edwin Stanton, wanted control over the telegraph lines to maintain the flow of information. Early in the war, one of Stanton's first acts of Secretary of War, was to move telegraph lines from ending at McClellan's headquarters to terminating at the War Department. Even Stanton himself said "[telegraph] is my right arm". Many Northern victories were found due to the use of the telegraph. Victories include the Battle of Antietam (1862), the Battle of Chickamauga (1863), and Sherman's March (1865).[66]

The telegraph system wasn't without its flaws. The USMT, while the main source of telegraphers and cable, was still a civilian agency. Most operators were first hired by the telegraph companies and then contracted out to the War Department. This created tension between Generals and their operators. One source of irritation was that USMT operators didn't have to follow military authority. Usually they performed without hesitation, but they didn't have to, so Albert Myer created a U.S. Army Signal Corps in February 1863. As the new head of the Signal Corps, Myer tried to get all telegraph and flag signaling under his command, and therefore subject to military discipline.After creating the Signal Corps, Myer pushed to further develop new telegraph systems. While the USMT relied primarily on civilian lines and operators, the Signal Corp's new field telegraph could be deployed and dismantled faster than USMT's system.[66]

First World War

During World War I, Britain's telegraph communications were almost completely uninterrupted, while it was able to quickly cut Germany's cables worldwide.[67] British access to transatlantic cables and its codebreaking expertise led to the Zimmermann Telegram incident that contributed to the US joining the war.[68]

Second World War

World War II revived the 'cable war' of 1914-1918. In 1939, German-owned cables across the Atlantic were cut once again, and, in 1940, Italian cables to South America and Spain were cut in retaliation for Italian action against two of the five British cables linking Gibraltar and Malta. Electra House, Cable & Wireless's head office and central cable station, was damaged by German bombing in 1941.[69]

The Germans developed a highly complex teleprinter cipher attachment (German: Schlüssel-Zusatz) that was used for telegrams between German High Command (OKW) and the army groups in the field. These contained situation reports, battle plans and discussions of strategy and tactics. Britain intercepted radio teleprinter signals, diagnosed how the encrypting machine worked and decrypted a large amount of teleprinter traffic.[70] (See: Cryptanalysis of the Lorenz cipher.)

End of the telegraph era

In America, the end of the telegraph era can be associated with the fall of the Western Union Telegraph Company.[66] Western Union was the leading telegraph provider for America and was seen as the best competition for the National Bell Telephone Company. Western Union and Bell were both invested in telegraphy and telephone technology. Western Union's decision to allow Bell to gain the advantage in telephone technology was the result of Western Union's upper management's failure to foresee the surpassing of the telephone over the, at the time, dominant telegraph system. Western Union soon lost the legal battle for the rights to their telephone copyrights. This led to Western Union agreeing to a lesser position in the telephone competition, which in turn led to the lessening of the telegraph.[66]

While the telegraph was not the focus of the legal battles that occurred around 1878, the companies that were affected by the effects of the battle were the main powers of telegraphy at the time. Western Union thought that the agreement of 1878 would solidify telegraphs as the long-range communication of choice. However, due to the underestimates of telegraph's future and poor contracts, Western Union found itself declining.[66] AT&T acquired working control of Western Union in 1909 but relinquished it in 1914 under threat of antitrust action. AT&T bought Western Union's electronic mail and Telex businesses in 1990.

Although commercial "telegraph" services are still available in many countries, transmission is usually done by some form of data transmission other than traditional telegraphy.

See also

References

  1. ^ Tancia (2014), A History of Telegraphy (PDF)
  2. ^ E. A. Marland, Early Electrical Communication, Abelard-Schuman Ltd, London 1964, no ISBN, Library of Congress 64-20875, pages 17-19;
  3. ^ Electromagnetic Telegraph - Invented by Baron Pavel Schilling
  4. ^ Prevost, 1805, pp. 176-178
  5. ^ a b Jones 1965.
  6. ^ 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
  7. ^ R. V. G. Menon (2011). Technology and Society. India: Dorling Kindersley.
  8. ^ Henry Pitt Phelps (1884). The Albany Hand-book: A Strangers' Guide and Residents' Manual. Albany: Brandow & Barton. p. 6.
  9. ^ Gibberd 1966.
  10. ^ Thomas Coulson (1950). Joseph Henry: His Life and Work. Princeton: Princeton University Press.
  11. ^ "Edward Davy". Australian Science Archives Project. Retrieved 7 June 2012.
  12. ^ Kieve, pp. 23-24
  13. ^ Appleyard, R. (1930). Pioneers of Electrical Communication. Macmillan.
  14. ^ Norman, Jeremy. "Francis Ronalds Builds the First Working Electric Telegraph (1816)". HistoryofInformation.com. Retrieved 1 May 2016.
  15. ^ Ronalds, B.F. (2016). "Sir Francis Ronalds and the Electric Telegraph". Int. J. for the History of Engineering & Technology. doi:10.1080/17581206.2015.1119481.
  16. ^ Ronalds, Francis (1823). Descriptions of an Electrical Telegraph and of some other Electrical Apparatus. London: Hunter.
  17. ^ Ronalds, B.F. (Feb 2016). "The Bicentennial of Francis Ronalds's Electric Telegraph". Physics Today. doi:10.1063/PT.3.3079.
  18. ^ Ronalds, B.F. (2016). Sir Francis Ronalds: Father of the Electric Telegraph. London: Imperial College Press. ISBN 978-1-78326-917-4.
  19. ^ Fahie, John Jacob (1884). A History of Electric Telegraphy, to the Year 1837 (PDF). E. & F.N. Spon. pp. 307–319. Retrieved 21 November 2017.
  20. ^ Huurdeman 2003, p. 54.
  21. ^ Calvert 2008.
  22. ^ Howe, p. 7
  23. ^ History.com Staff (2009), Morse Code & the Telegraph, A+E Networks
  24. ^ The telegraphic age dawns BT Group Connected Earth Online Museum. Accessed December 2010, archived 10 Feb 2013
  25. ^ a b Bowers, page 129
  26. ^ Huurdeman 2003, p. 67.
  27. ^ Huurdeman 2003, pp. 67–68.
  28. ^ Beauchamp 2001, p. 35.
  29. ^ Huurdeman 2003, p. 69.
  30. ^ Huurdeman 2003, pp. 67-69.
  31. ^ Nichols, John (1967). The Gentleman's magazine, Volumes 282–283. p. 545. University of California
  32. ^ Paul Atterbury. "Victorian Technology". BBC.
  33. ^ Freebody, J. W. (1958), "Historical Survey of Telegraphy", Telegraphy, London: Sir Isaac Pitman & Sons, Ltd., pp. 30, 31
  34. ^ Laurence Turnbull, Electro-magnetic telegraph, p. 77, Philadelphia: A. Hart, 1853 OCLC 60717772
  35. ^ Lewis Coe, The Telegraph: A History of Morse's Invention and Its Predecessors in the United States, p. 69, McFarland, 2003 ISBN 0786418087.
  36. ^ Andrew L. Russell, Open Standards and the Digital Age, p. 36, Cambridge University Press, 2014 ISBN 1107039193.
  37. ^ Today in History - 24 October, The Transcontinental Telegraph and the End of the Pony Express, Library of Congress, retrieved 3 February 2017.
  38. ^ Christine Rider, ed., Encyclopedia of the Age of the Industrial Revolution, 1700–1920 (2007) 2:440.
  39. ^ Taliaferro Preston Shaffner, The Telegraph Manual: A Complete History and Description of the Semaphoric, Electric and Magnetic Telegraphs of Europe, Asia, Africa, and America, Ancient and Modern: with Six Hundred and Twenty-five Illustrations (1867).
  40. ^ Richard B. Du Boff, "Business Demand and the Development of the Telegraph in the United States, 1844–1860." Business History Review 54#4 (1980): 459–479.
  41. ^ John Liffen, "The Introduction of the Electric Telegraph in Britain, a Reappraisal of the Work of Cooke and Wheatstone." International Journal for the History of Engineering & Technology (2013).
  42. ^ Roberts, Steven (2012), A History of the Telegraph Companies in Britain between 1838–1868, retrieved 8 May 2017
  43. ^ Oslin, George P. The Story of Telecommunications, Mercer University Press, 1992. 69.
  44. ^ Oslin, George P. The Story of Telecommunications. Mercer University Press, 1992. 67
  45. ^ "Royal Earl House Printing-Telegraph Patent #4464, 1846". Retrieved 2014-04-25.
  46. ^ "Royal Earl House Steam-Powered Printing-Telegraph Patent #9505, 1852". Retrieved 2014-04-25.
  47. ^ Oslin, George, P. The Story of Telecommunications, 1992. 71
  48. ^ "David Edward Hughes". Clarkson University. 14 April 2007. Archived from the original on 2008-04-22. Retrieved 2010-09-29.
  49. ^ Beauchamp 2001, pp. 394–395.
  50. ^ Phillip R. Easterlin, "Telex in New York", Western Union Technical Review, April 1959: 45
  51. ^ https://www.explainthatstuff.com/fiberoptics.html
  52. ^ a b Haigh, K R (1968). Cable Ships and Submarine Cables. London: Adlard Coles Ltd. pp. 26–27.
  53. ^ Wilson, Arthur (1994). The Living Rock: The Story of Metals Since Earliest Times and Their Impact on Civilization. p. 203. Woodhead Publishing. ISBN 978-1-85573-301-5.
  54. ^ Briggs, Asa and Burke, Peter: "A Social History of the Media: From Gutenberg to the Internet", p110. Polity, Cambridge, 2005.
  55. ^ Conley, David and Lamble, Stephen (2006) The Daily Miracle: An introduction to Journalism,(Third Edition) Oxford University Press, Australia pp. 305-307
  56. ^ Kennedy, P. M. (October 1971). "Imperial Cable Communications and Strategy, 1870-1914". The English Historical Review. 86 (341): 728–752. doi:10.1093/ehr/lxxxvi.cccxli.728. JSTOR 563928.
  57. ^ Headrick, D.R., & Griset, P. (2001). Submarine telegraph cables: business and politics, 1838-1939. The Business History Review, 75(3), 543-578.
  58. ^ Sir John Pender
  59. ^ Evolution of Eastern Telegraph Company
  60. ^ Origins of the Eastern & Associated Telegraph Companies
  61. ^ Roberts, Steven (2012), Distant Writing A History of Telegraph Companies in Britain between 1838 and 1868: 16. Telegraph at War 1854 - 1868
  62. ^ Figes 2010, pp. 306–09.
  63. ^ Figes 2010, pp. 304–11.
  64. ^ Hochfelder, David (2019), Essential Civil WAR Curriculum: The Telegraph, Virginia Center for Civil War Studies at Virginia Tech
  65. ^ a b c Schwoch 2018.
  66. ^ a b c d e f g Hochfelder 2012.
  67. ^ Kennedy 1971.
  68. ^ "The telegram that brought America into the First World War". BBC History Magazin e. 17 January 2017.
  69. ^ Company-Histories.com Cable and Wireless plc Source: International Directory of Company Histories, Vol. 25. St. James Press, 1999.
  70. ^ Copeland 2006, pp. 1-6.

Bibliography

  • Beauchamp, Ken (2001), History Of Telegraphy, London: The Institution Of Electrical Engineers, ISBN 978-0-85296-792-8
  • Bowers, Brian, Sir Charles Wheatstone: 1802–1875, IET, 2001 ISBN 0852961030.
  • Calvert, J. B. (2008), The Electromagnetic Telegraph
  • Copeland, B. Jack, ed. (2006), Colossus: The Secrets of Bletchley Park's Codebreaking Computers, Oxford: Oxford University Press, ISBN 978-0-19-284055-4
  • Figes, Orlando (2010). Crimea: The Last Crusade. London: Allen Lane. ISBN 978-0-7139-9704-0.
  • Gibberd, William (1966), Australian Dictionary of Biography: Edward Davy
  • Hochfelder, David (2012). The Telegraph in America, 1832-1920. Johns Hopkins University Press. pp. 6–17, 138–141. ISBN 9781421407470.
  • Huurdeman, Anton A. (2003), The Worldwide History of Telecommunications, Wiley-Blackwell, ISBN 978-0471205050
  • Jones, R. Victor Samuel Thomas von Sömmering's "Space Multiplexed" Electrochemical Telegraph (1808-10), Harvard University website. Attributed to "Semaphore to Satellite" , International Telecommunication Union, Geneva 1965. Retrieved 2009-05-01
  • Kennedy, P. M. (October 1971). "Imperial Cable Communications and Strategy, 1870-1914". The English Historical Review. 86 (341): 728–752. doi:10.1093/ehr/lxxxvi.cccxli.728. JSTOR 563928.
  • Kieve, Jeffrey L., The Electric Telegraph: A Social and Economic History, David and Charles, 1973 OCLC 655205099.
  • Mercer, David, The Telephone: The Life Story of a Technology, Greenwood Publishing Group, 2006 ISBN 031333207X.
  • Schwoch, James (2018). Wired into Nature: The Telegraph and the North American Frontier. University of Illinois Press. ISBN 9780252041778.

Further reading

External links

André-Marie Ampère

André-Marie Ampère (; French: [ɑ̃pɛʁ]; 20 January 1775 – 10 June 1836) was a French physicist and mathematician who was one of the founders of the science of classical electromagnetism, which he referred to as "electrodynamics". He is also the inventor of numerous applications, such as the solenoid (a term coined by him) and the electrical telegraph. An autodidact, Ampère was a member of the French Academy of Sciences and professor at the École polytechnique and the Collège de France.

The SI unit of measurement of electric current, the ampere, is named after him. His name is also one of the 72 names inscribed on the Eiffel Tower.

CNCP Telecommunications

CNCP Telecommunications (Canadian National-Canadian Pacific Telecommunications) was an electrical telegraph operator and later as a telecom company. CNCP was created as a joint venture between the Canadian National Railway and the Canadian Pacific Railway in 1967, replacing the different networks used by the two railway companies (CN Telegraph interchanged traffic with the Postal Telegraph Cable Company in the US while CPR Telegraphs networked with Western Union). The two networks, former rivals, had been co-operating increasingly since the 1930s By 1980, CNCP was no longer a telegraph company and emerged as an early telecom company. A 40% stake was acquired by Rogers Communications in 1984 and CP acquired CN's stake. The network was dissolved in 1988 and Rogers renamed the company Unitel Communications Incorporated in 1989. The new company was later acquired by AT&T Canada, now known as Allstream (now part of Zayo Group). The telegram division was later acquired by iTelegram and renamed Telegrams Canada in 2002 and based in Toronto.

Character encoding

Character encoding is used to represent a repertoire of characters by some kind of encoding system. Depending on the abstraction level and context, corresponding code points and the resulting code space may be regarded as bit patterns, octets, natural numbers, electrical pulses, etc. A character encoding is used in computation, data storage, and transmission of textual data. "Character set", "character map", "codeset" and "code page" are related, but not identical, terms.

Early character codes associated with the optical or electrical telegraph could only represent a subset of the characters used in written languages, sometimes restricted to upper case letters, numerals and some punctuation only. The low cost of digital representation of data in modern computer systems allows more elaborate character codes (such as Unicode) which represent most of the characters used in many written languages. Character encoding using internationally accepted standards permits worldwide interchange of text in electronic form.

Charles Williams Jr. House

The Charles Williams Jr. House, built in 1858, is a historic house at 1 Arlington Street in Somerville, Massachusetts. Charles Williams Jr. was a manufacturer of electrical telegraph instruments at 109 Court Street in Boston. Alexander Graham Bell and Thomas A. Watson experimented with the telephone in Williams' shop, and it was there that they first heard indistinct sounds transmitted on June 2, 1875. The first permanent residential telephone service in the world was installed at this house in 1877, connecting Williams' home with his shop on Court Street in Boston. Williams had telephone Numbers 1 and 2 of the Bell Telephone Company.

Cooke and Wheatstone telegraph

The Cooke and Wheatstone telegraph was an early electrical telegraph system dating from the 1830s invented by English inventor William Fothergill Cooke and English scientist Charles Wheatstone. It was the first telegraph system to be put into commercial service. The receiver consisted of a number of needles which could be moved by electromagnetic coils to point to letters on a board. This feature was liked by early users who were unwilling to learn codes, and employers who did not want to invest in staff training.

In later systems the letter board was dispensed with, and the code was read directly from the movement of the needles. This came about because the number of needles was reduced, leading to more complex codes. The change was motivated by the economic need to reduce the number of telegraph wires used, which was related to the number of needles. The change became more urgent as the insulation of some of the early installations deteriorated, causing some of the original wires to be unusable. Cooke and Wheatstone's most successful system was eventually a one-needle system that continued in service into the 1930s.

Cooke and Wheatstone's telegraph played a part in the apprehension of the murderer John Tawell. Once it was known that Tawell had boarded a train to London, the telegraph was used to signal ahead to the terminus at Paddington and have him arrested there. The novelty of this use of the telegraph in crime-fighting generated a great deal of publicity and led to increased acceptance and use of the telegraph by the public.

East Tytherley

East Tytherley is a small village in Hampshire, England.The name Tytherley comes from Old English and means thin or tender wood.The village was given to Queen Philippa by her husband Edward III in 1335. When the Black Death spread through London she moved her court to the village.In more recent history William Fothergill Cooke invented the first commercial electrical telegraph whilst living in the village.

Friedrich Clemens Gerke

Friedrich Clemens Gerke (22 January 1801 – 21 May 1888) was a German writer, journalist, musician and pioneer of telegraphy who revised the Morse code in 1848. It is Gerke's version of the original (American) Morse code now known as the International Morse code and standardized by the ITU (International Telecommunications Union) which is used today.

Giuseppe Domenico Botto

Giuseppe Domenico Botto (4 April 1791 – 20 March 1865) was an Italian physicist.

Born at Moneglia, he studied at the University of Genoa and the École Polytechnique in Paris. The chair of General and Experimental Physics was assigned to G.D Botto in 1828. Experimental work was dedicated to magnetic, thermal, and chemical effects of electrical currents and induction of currents.In 1830 Botto described in a note a prototype electric motor on which he was working and published a description of it in a Memoria titled "Machine Loco-motive mise en mouvement par l'électro-magnétisme" to the Academy of Turin around 1836.

A device built on the basis of his description was part of the collection of scientific instruments of the Grand Duke of Tuscany, which is now kept at the Institute and Museum of History of Science in Florence. In the following years he published more work on improving efficiency of electric motors.

Botto experimented with electrolysis of water using a manual generator of electric sparks, the electric magnet designed by Leopoldo Nobili and Vincenzo Antinori on the basis of the discovery of' electromagnetic induction made by Michael Faraday in 1831. In 1833 he tested an iron-platinum thermocouple wrapped as a chain around a wooden stick which generated a current when heat from a flame was applied,. The heat from the flame created a temperature difference, and the thermocouple converted the temperature difference into an electric voltage.He also worked on other subjects and published in 1846 a note for the improvement of agriculture in Piedmont. In 1849 he proposed a new system for transmission and encoding for the electrical telegraph system (notes on this subject were recently discovered in the archives of the Museo Sanguineti Leonardini of Chiavari.)

He died at Turin in 1865.

History of telecommunication

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.

History of the telephone

This history of the telephone chronicles the development of the electrical telephone, and includes a brief review of its predecessors.

Jackfish, Ontario

Jackfish is a ghost town in northern Ontario, Canada, located on the north shore of Lake Superior east of Terrace Bay.

The last spike on the Canadian Pacific Railway (CPR) track between Montreal and Winnipeg was driven in west of Jackfish on May 16, 1885.[1][2][3] Laying one particular mile of railway in this area is said to have cost $700,000.

Jackfish was established as a train order station on the CPR following the period of railway construction between 1883 and 1885. Initially a siding or passing track was built at this location to allow east and westbound trains to operate on the single track main line. An electrical telegraph enabled the station operator to control the movement of trains with information received from a train dispatcher.

With its location as a railway siding, along a beach area, amongst Lake Superior's otherwise rocky shoreline, Jackfish became a port of commercial fishing. Fish were caught here and packed in ice and loaded aboard trains bound for markets in Toronto and Montreal.

In 1895 Jackfish was established as a port to receive coal required as fuel for steam trains travelling on the CPR.[4] A dock outfitted with cranes allowed large ships to unload their cargo.[5] From this point, the coal was loaded into cars and delivered to CPR coaling depots such as Schreiber and White River. With the increased activity of steam locomotives shunting cars around, a large water tower was located near the railway tracks.

In the 1930s A lumber company here sent logs by ship for use at pulp mills in the United States.[6]

During World War II, young Canadian men of Japanese origin from British Columbia were sent to road construction camps, including one at Jackfish, to work on the construction of the Trans-Canada Highway.

With the dieselization of CPR's motive power and replacement of its steam engines in the 1950s, the fortunes of the town began to decline. The fish stocks also collapsed with the introduction of the sea lamprey into the Great Lakes.

The Lakeview Hotel at Jackfish, built at the end of the 19th century, remained a popular stopping place during the summer for a number of years. The hotel burned down in 1960. By September, 1963 two families remained in Jackfish and they moved out of the town a month later. Hence,the town site was totally abandoned by 1963.

The name Jackfish and its railroad connection still exist. The Canadian Pacific Railway operates and maintains a siding named Jackfish located just east of the original Jackfish townsite. The siding is part of the operating infrastructure making up the Heron Bay Subdivision, a defined piece of track which extends from White River to Schreiber, Ontario. Jackfish siding is 14,000 feet in length. It is a signalled siding rated for 30 mph. The signals and switches are part of a Centralized Traffic Control (CTC) system operated by a Rail Traffic Controller situated in Canadian Pacific Railway's headquarters in Calgary, Alberta.

"Jackfish" is a common name for the Northern Pike.

Optical communication

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.

An optical communication system uses a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. When electronic equipment is not employed the 'receiver' is a person visually observing and interpreting a signal, which may be either simple (such as the presence of a beacon fire) or complex (such as lights using color codes or flashed in a Morse code sequence).

Free-space optical communication has been deployed in space, while terrestrial forms are naturally limited by geography, weather and the availability of light. This article provides a basic introduction to different forms of optical communication.

Pavel Schilling

Baron Pavel L'vovitch Schilling, also known as Paul Schilling (5 April 1786, Reval (now, Tallinn), Russian empire – St. Petersburg, Russia, 25 July 1837), was a diplomat of Baltic German origin employed in the service of Russia in Germany, and who built a pioneering electrical telegraph. It consisted of a single needle system which used a telegraph code to indicate the characters in a message.

Schilling's first electromagnetic telegraph cable line was set up in his apartment in St Petersburg. In 1832, Schilling demonstrated the long-distance transmission of signals by positioning two telegraphs of his invention—his device was said to be the first electromagnetic telegraph in the world—in two different rooms of his apartment. Schilling was the first to put into practice the idea of a binary system of signal transmissions. Schilling's contributions to electrical telegraphy were named an IEEE Milestone in 2009.The most important exhibit in the telegraph collection of the A.S. Popov Central Museum of Communications is reputed to be Schilling's telegraph of 1832. A demonstration device was set up in 1835 on an underground line around the Admiralty building. An operational line between Kronstadt and the Peterhof Palace was planned but cancelled after Schilling's death.

Quadruplex telegraph

The Quadruplex telegraph is a type of electrical telegraph which allows a total of four separate signals to be transmitted and received on a single wire at the same time (two signals in each direction). Quadruplex telegraphy thus implements a form of multiplexing.

The technology was invented by American inventor Thomas Edison, who sold the rights to Western Union in 1874 for the sum of $10,000.

The problem of sending two signals simultaneously in opposite directions on the same wire had been solved previously by Julius Wilhelm Gintl and improved to commercial viability by J. B. Stearns; Edison added the ability to double the number in each direction.

To send two signals in a single direction at the same time, the quadruplex telegraph used one signal to vary the absolute strength or voltage of the signal (amplitude modulation) and the other signal to vary the phase (polarity) of the line (phase modulation), i.e., the direction of current flow imposed upon the wire.Today this concept is known as polar modulation, considering amplitude and phase as radius and angle in polar coordinates.

Salt Hill

Salt Hill is a district within the unitary authority of Slough in Berkshire in the south of England, close to London. Before 1974, Salt Hill was part of Buckinghamshire. It is to the north of Chalvey and the Great West Road, surrounding Salt Hill Park.

The name Salt Hill is derived from Montem Mound in Chalvey, which was also known as Salt Hill, or Salts Hill.

In 1807, the French nobleman Antoine Philippe, Duke of Montpensier died here of tuberculosis on the way from London to Devon.

On 1 January 1845, John Tawell, who had recently returned from Australia, murdered his lover, Sarah Hart, at Salt Hill by poisoning her with prussic acid. With various officials in chase, Tawell fled to Slough railway station and boarded a train to Paddington. The electrical telegraph had recently been installed and so a message was sent ahead to Paddington with Tawell's details. Tawell was trailed and subsequently arrested, tried and executed for the murder at Aylesbury on 28 March 1845. This is believed to be the first time ever that the telegraph had been involved in the apprehension of a murderer.

On 6 February 1870 William MacBean George Colebrooke K.B. died at his home here. He, along with fellow Utilitarian Charles Hay Cameron had been responsible for the Colebrooke-Cameron Commission report, which brought constitutional government to Ceylon (later Sri Lanka)Sri Lanka and marks the beginning of the modern era in that country. He had also presided over a constitutional crisis in New Brunswick and had been Governor of British Guiana.

Salt Hill Park once boasted great iron gates, which were subsequently smelted as part of the war effort during World War II.

Semaphore telegraph

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. 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).

Telegraph key

A telegraph key is a specialized electrical switch used by a trained operator to transmit text messages in telegraph systems, usually in Morse code. Keys are used in all forms of electrical telegraph systems, such as landline or "wire" electrical telegraphy, and "wireless", or radio telegraphy. An operator taps on the switch, connecting and disconnecting the electrical circuit, creating electrical pulses of two different lengths called "dots" and "dashes", to spell out text messages in code.

Telegraphy

Telegraphy (from Ancient Greek: τῆλε, têle, "at a distance" and γράφειν, gráphein, "to write") is the long-distance transmission of textual or symbolic (as opposed to verbal or audio) messages without the physical exchange of an object bearing the message. Thus semaphore is a method of telegraphy, whereas pigeon post is not.

Telegraphy requires that the method used for encoding the message be known to both sender and receiver. Many methods are designed according to the limits of the signalling medium used. The use of smoke signals, beacons, reflected light signals, and flag semaphore signals are early examples.

In the 19th century, the harnessing of electricity led to the invention of electrical telegraphy. The advent of radio in the early 20th century brought about radiotelegraphy and other forms of wireless telegraphy. In the Internet age, telegraphic means developed greatly in sophistication and ease of use, with natural language interfaces that hide the underlying code, allowing such technologies as electronic mail and instant messaging.

William Fothergill Cooke

Sir William Fothergill Cooke (4 May 1806 – 25 June 1879) was an English inventor.

He was, with Charles Wheatstone, the co-inventor of the Cooke-Wheatstone electrical telegraph, which was patented in May 1837. Together with John Lewis Ricardo he founded the Electric Telegraph Company, the world's first public telegraph company, in 1846. He was knighted in 1869.

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.