The Full Wiki

Electrical telegraph: Wikis

Advertisements
  
  
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Did you know ...


More interesting facts on Electrical telegraph

Include this on your site/blog:

Encyclopedia

Advertisements

From Wikipedia, the free encyclopedia

The electrical telegraph is a telegraph that uses electric signals. The electromagnetic telegraph is a device for human-to-human transmission of coded text messages over wire. The electrical telegraph replaced such optical telegraphy systems as those designed by Claude Chappe for the French military, and Friedrich Clemens Gerke for the Prussian military.

Contents

History

Early works and messages

"Early Telegraph" historical marker outside Elizabethtown, Pennsylvania

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 in later more advanced studies, electromagnetism - were applied by various people to the problems of detecting controlled transmissions of electricity at various distances.

In 1746 the French scientist and abbé Jean-Antoine Nollet gathered about two hundred monks into a circle about a mile (1.6 km) in circumference, with pieces of iron wire connecting them and discharged a battery of Leyden jars through them; he observed that each man reacted at substantially the same time to the electric shock, showing the speed of propagation to be very high.[1][2]

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.[3] 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.

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 Catalan polymath and scientist Francisco Salvá i Campillo.[4] Both their designs employed multiple wires (up to 35) in order to visually 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 electrical 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 visually observe the bubbles and could then record the transmitted message, albeit at a very low baud rate.[4] The principal disadvantage to the system was its prohibitive cost, due to having to manufacture and string-up the multiple wire circuits it employed, as opposed to the single wire (with ground return) used by later telegraphs.

In 1816, Francis Ronalds set up a primitive telegraph. He ran eight miles (13 km) of cable (encased in glass tubing) through his back garden suspending it from two wooden lattices. and succeeded in getting an electrical signal along the full length using static high voltage electricity. At both ends there were clockwork operated dials with numbers and letters of the alphabet.[5]

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.

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.

In 1832 an electromagnetic telegraph was created by Baron Schilling in Russia, and in 1833 Carl Friedrich Gauss and Wilhelm Weber invented their own code to communicate over a distance of 1200 m within Göttingen, Germany.

Then in 1835 Joseph Henry invented the critical electrical relay, by which a weak current could operate a powerful local electromagnet over very long distances.[6][7]

Schilling telegraph

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. These served for switching the electric current. The receiving instrument consisted of 6 galvanometers with magnetic needles, suspended from the silk threads. Both stations of Shilling'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. Later Pavel Shilling improved its apparatus. He reduced the number of connecting wires from 8 to 2.

On October 21, 1832, Schilling managed a short-distance transmission of signals between two telegraphs in different rooms of his apartment. In 1836 the Schilling's telegraph was tested on a 5 km experimental underground - underwater cable, laid around the building of the main Admiralty in Saint Petersburg. Schilling also was one of the first to put into practice the idea of the binary system of signal transmission.

William Fothergill Cooke studied anatomy in Heidelberg in 1834-6, where the physics professor introduced him to the Schilling telegraph in 1836.

Gauss-Weber telegraph and Carl Steinheil

Carl Friedrich Gauss, one of the most influential mathematicians of the early 19th century, developed a new theory of the Earth's magnetism in 1831, together with the physics professor Wilhelm Weber in Göttingen. Among the most important inventions of the time was the unifilar and bifilar magnetometer, enabling them to measure even the smallest deflections of the needle. They installed a 1200 m long wire above the town's roofs, which they were given permission for on 6 May 1833. 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, they used the telegraph to coordinate time, but soon they developed other signals; finally, their own alphabet. It was not binary, but based on four amplitudes of the needle. Gauss was convinced that this communication would be a help to his kingdom's towns.

Later 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 received funding from Alexander von Humboldt. Carl August Steinheil in Munich was able to build a telegraph network within the city in 1835-6, and installed a telegraph line along the first German railroad in 1835.

Alter and the Elderton Telegraph

Across the Atlantic, in 1836 an American scientist, Dr. David Alter, invented the first known American electric telegraph, in Elderton, Pennsylvania, one year before the much more popular Morse telegraph was invented. Alter demonstrated it to witnesses. He was interviewed later for the book Biographical and Historical Cyclopedia of Indiana and Armstrong Counties, in which he said: "I may say that there is no connection at all between the telegraph of Morse and others and that of myself.... Professor Morse most probably never heard of me or my Elderton telegraph."

Commercialization

Cooke and Wheatstone's electric telegraph

The first commercial electrical telegraph was constructed by Sir William Fothergill Cooke. Cooke and Charles Wheatstone patented it in May 1837 as an alarm system. It was first successfully demonstrated by Cooke and Wheatstone on 25 July 1837 between Euston and Camden Town in London.[8] It entered commercial use on the Great Western Railway over the 13 miles (21 km) from Paddington station to West Drayton on 9 April 1839. In early 1845, John Tawell was apprehended following the use of a needle telegraph message from Slough to Paddington on 1 January 1845. This is thought to be the first use of the telegraph to catch a murderer. The message was:

A MURDER HAS GUST BEEN COMMITTED AT SALT HILL AND THE SUSPECTED MURDERER WAS SEEN TO TAKE A FIRST CLASS TICKET TO LONDON BY THE TRAIN WHICH LEFT SLOUGH AT 742 PM HE IS IN THE GARB OF A KWAKER WITH A GREAT COAT ON WHICH REACHES NEARLY DOWN TO HIS FEET HE IS IN THE LAST COMPARTMENT OF THE SECOND CLASS COMPARTMENT

The Cooke-Wheatstone system did not support punctuation, lower case, or the letters J, Q, and Z; hence the misspelling of 'just' and 'Quaker'. "Second class compartment" should also probably read "second first-class carriage"; this information was not significant, however, as Tawell was not arrested at the station, but at a nearby coffee shop.[9]

Morse telegraphs

In the United States, the telegraph was developed by Samuel Morse and Alfred Vail. Samuel F. B. Morse independently developed an electrical telegraph in 1837, an alternative design that was capable of transmitting over long distances using poor quality wire. His assistant, Alfred Vail developed the Morse code signalling alphabet with Morse. The Morse code alphabet commonly used on the device was also named after Morse.

On 6 January 1838 Morse first successfully tested the device at the Speedwell Ironworks near Morristown, New Jersey, and on 8 February he publicly demonstrated it to a scientific committee at the Franklin Institute in Philadelphia, Pennsylvania.

In 1843 the U.S. Congress appropriated $30,000 to fund an experimental telegraph line from Washington, D.C. to Baltimore. By May 1, 1844 the line had been completed from the U.S. Capitol to Annapolis Junction in Maryland. That day the Whig Party nominated Henry Clay at its national convention in Baltimore. News of the nomination was hand carried by railroad to Annapolis Junction where Vail wired it to Morse in the Capitol.[10] On 24 May 1844, after the line was completed, Morse made the first public demonstration of his telegraph by sending a message from the Supreme Court Chamber in the U.S. Capitol in Washington, D.C. to the B&O Railroad "outer depot" (now the B&O Railroad Museum) in Baltimore. The famous message was: What hath God wrought (from the Biblical book of Numbers 23:23: Surely there is no enchantment against Jacob, neither is there any divination against Israel: according to this time it shall be said of Jacob and of Israel, What hath God wrought!).

The Americas' first telegram, transmitted via a repeater: "What hath God wrought" sent by Samuel F.B. Morse in 1844.

The Morse/Vail telegraph was quickly deployed in the following two decades. Morse failed to properly credit Vail for the powerful electromagnets used in his telegraph. The original Morse design, without the relay or the "intensity" and "quantity" electromagnets invented by Vail only worked to a distance of 40 feet (12 m).

The electrical telegraph owned and built by Samuel F. B. Morse

This was a practical electrical telegraph system, and subsequently electrical telegraph came to refer to a signaling telegram - a system where an operator makes and breaks an electrical contact with a telegraph key which results in an audible signal at the other end produced by a telegraph sounder which is interpreted and transcribed by a human. Morse and Vail's first telegraphs used a pen and paper system to record the marks of the Morse Code, and interpreted the marks visually however, operators soon realized that they could "read" the clicking of the receiver directly by ear. Systems which automatically read the signals and print formed characters are generally called teletype rather than telegraph systems. Some electrical telegraphs used indicators which were read visually rather than by ear. The most notable of these was the early transatlantic telegraph cable.

According to a Pennsylvania Historical and Museum Commission heritage marker installed along Pennsylvania Route 230 near Elizabethtown, Pennsylvania in 1947 (see image at right), the first commercial telegraph line in the United States ran along a railroad right-of-way (currently part of Amtrak's Keystone Corridor) between Lancaster, Pennsylvania and Harrisburg, Pennsylvania in 1845. The first message, received on January 8, 1846, was "Why don't you write, you rascals?"[11]

As the transcontinental telegraph was laid it passed through Nebraska where Republican sympathizers prior to American Civil War were eager to gain statehood for Nevada before the next presidential election so that Abraham Lincoln would have enough votes to win. They rushed to send the entire state constitution by telegraph to the United States Congress, which approved it and sent it to the President for signature. They did not believe sending it by train would guarantee it would arrive on time. The constitution was sent on October 31, just 8 days before the election on November 7, 1864.

On 24 October 1861, the first transcontinental telegraph system was established. Spanning North America, an existing network in the eastern United States was connected to the small network in California by a link between Omaha and Carson City via Salt Lake City. The first telegram on that line was sent by Brigham Young then governor or Utah which affirmed that the Territory had not seceded. It read "Utah has not seceded but is firm for the Constitution and the laws of our once happy country." [12] The slower Pony Express system ceased operation two days later. Carson City has another claim in the history of telegraphs for the largest and costliest transmission ever sent came from there.

Transatlantic era

Major telegraph lines in 1891
Transatlantic era

The first successful transatlantic telegraph cable was completed on 27 July 1866, allowing transatlantic telegraph communications for the first time. Earlier submarine transatlantic cables installed in 1857 and 1858 only operated for a few days or weeks before they failed. The study of underwater telegraph cables accelerated interest in mathematical analysis of these transmission lines.

In 1867, David Brooks (while working for the Central Pacific Railroad) was awarded U.S. Patent 63,206 and U.S. Patent 69,622 for his improvements to telegraph insulators. He was also awarded reissue number 2,717 in 1867, for U.S. Patent 45,221, which was originally awarded to him on 1864, for his insulator design. Brooks' patents allowed the Central Pacific to more easily communicate with construction crews building the First Transcontinental Railroad in America; the completion of the railroad was broadcast by telegraph on May 10, 1869, with the telegrapher striking his key in unison with the strikes on the Golden Spike during the completion ceremony.

Another advancement in telegraph technology occurred on August 9, 1892, when Thomas Edison received a patent for a two-way telegraph (U.S. Patent 0,480,567, "Duplex Telegraph") .

Global communication

Within 29 years of its first installation at Euston Station, the telegraph network crossed the oceans to every continent but Antarctica, making instant global communication possible for the first time. The telegraph's greatest accomplishment was to expand information boundaries, allowing data to reach its destination before its usefulness expired; information like any other goods is only of value for a certain period of time. For instance, a person making a speculation in stocks requires the current market price; the old market price is of no value. As long as information travels at the speed of transportation vehicles, the distance over which it held its freshness was small.[13] A similar principle applies to news, so much so that the relationship between information and time results in the distinguishing news from history. Information about events that were at a significant distance were reported long after the events occurred, rendering it as history to the individuals that received it. Thus the telegraph liberated information transfer from transportation. The impetus of this was war, which created the need of expanding the telegraph's service. Its effects were immediate, reducing more than a day off delivery time.[14]

News through newspapers also evolved due to the telegraph's inception. The telegraph could carry information, but there was a need for someone to obtain information to begin with. Through the rapid delivery of information created by the telegraph, it was no longer possible to rely on the delivery of distant newspapers. There was a need for an individual to gather the news at its distant source and deliver it to the telegraph office.[15 ] Newspapers could not use their own reporters as they would obstruct other reporters, jamming the telegraph line. The solution was co-operation. In New York for instance, the six major newspapers established an association for foreign news and a separate one for other sources - the first wire service. Ultimately this resulted in the proliferation of news with competition breaking out between the original six papers and other rivals. Thus the telegraph did not only transport news but also played a dominant role in establishing the industry and the profession of journalism.[15 ]

Applications

In many instances, applications of the electrical telegraph in the long period between its invention and demise as a significant carrier of information, were similar to current day Internet. This has prompted the sobriquet "Victorian Internet" for 19th century telegraphy. According to the book The Victorian Internet, besides news reporting, telegraphy, as the first true global network, permitted applications such as message routing, social networking (between Morse operators -- with gossiping and even marriages among operators were celebrated via telegraph), instant messaging, cryptography and text coding, abbreviated language slang, network security experts, hackers, wire fraud, mailing lists, spamming, e-commerce, stock exchange minute-by-minute reports (via the ticker tape machine invented by Thomas Alva Edison, and many others.

End of the telegraph era

On 27 January 2006, Western Union discontinued all telegram and commercial messaging services, though it still offered its money transfer services.

See also

References

  1. ^ Tom Standage, The Victorian Internet, Walker Publishing, New York, 1998 ISBN 0-8027-1342-4, pp. 1-2
  2. ^ John Joseph Fahie, A history of electric telegraphy, to the year 1837, Spon, London, 1884, p59
  3. ^ E. A. Marland, Early Electrical Communication, Abelard-Schuman Ltd, London 1964, no ISBN, Library of Congress 64-20875, pages 17-19;
  4. ^ a b 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
  5. ^ A collection of internet biographies
  6. ^ "Joseph Henry: Inventor of the Telegraph? Smithsonian Institution". http://www.si.edu/archives/ihd/jhp/joseph20.htm. Retrieved 2006-06-29.  
  7. ^ Thomas Coulson (1950). Joseph Henry: His Life and Work. Princeton: Princeton University Press.  
  8. ^ The electric telegraph, forerunner of the internet, celebrates 170 years BT Group Connected Earth Online Museum. Accessed July 2007
  9. ^ "John Tawell, The Man Hanged by the Electric Telegraph". University of Salford. http://www.cntr.salford.ac.uk/comms/johntawell.php. Retrieved 11 January 2009.  
  10. ^ The History of the Telegraph and Telegraphy at About.com
  11. ^ Pennsylvania Department of Labor & Industry: Historical Markers: Lancaster County. Accessed January 10, 2009.
  12. ^ Arrington, Leonard J., 1985, Brigham Young: The American Moses, New York: Knopf, p 294
  13. ^ Bray, John "The First Telegraph and Cable Engineers" in The Communications Miracle – The Telecommunications Pioneers from Morse to the Information Superhighway, Plenum Press, New York, 1995, pp 35-49
  14. ^ Thompson, Robert Luther, "Emergence of the American Telegraph" in Technology and Society – Wiring a Continent, The History of the Telegraph Industry in the United States 1832-1866, Arno Press, New York, 1972, pp299-310
  15. ^ a b Winston, Brian "The Telegraph" in Media Technology and Society, A History: From the Telegraph to the Internet, Routledge Publications, London, 1998, pp19-30

Further reading

External links


Simple English

The electrical telegraph is a telegraph that uses electric signals. In general the term electrical telegraph refers to a signalling system where an operator makes and breaks an electrical contact with a telegraph key which results in an audible signal at the other end produced by a telegraph sounder which is interpreted and transcribed by a human.

Contents

Types of electrical telegraphs

Gauss-Weber telegraph and Carl Steinheil

Carl Friedrich Gauss and Wilhelm Weber installed a 1000m long wire above the town's roofs. They were allowed to do this on 6 May 1833. Carl August Steinheil was able to build a telegraph network in 1835-6. He installed a telegraph line along the first German railroad in 1835.

Schilling telegraph

The telegraph had a transmitting device which had a keyboard with 16 black-and-white keys. These served for switching the electric current.

Alter and the Elderton Telegraph

Dr. David Alter created it one year before the much more popular Morse telegraph was invented. Alter demonstrated it publically.

Morse telegraphs

In the United States, the telegraph was developed by Samuel Morse and Alfred Vail. Morse created an electrical telegraph in 1837. His version was a design that could transmit over long distances using poor quality wire. Vail, his assistant, developed the Morse code signalling alphabet with Morse.

Other websites


Advertisements






Got something to say? Make a comment.
Your name
Your email address
Message