An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via telecommunication lines or radio. The electromagnetic telegraph is a device for human-to-human transmission of coded text messages.
The electrical telegraph, or more commonly just 'telegraph', superseded optical semaphore telegraph systems, such as those designed by Claude Chappe for the French military, and Friedrich Clemens Gerke for the Prussian military, thus becoming the first form of electrical telecommunications. In a matter of decades after their creation, electrical telegraph networks permitted people and commerce to almost instantly transmit messages across both continents and oceans, with widespread social and economic impacts.
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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 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. He then discharged a battery of Leyden jars through the human chain and observed that each man reacted at substantially the same time to the electric shock, showing that the speed of electricity's propagation was 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 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, 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]
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 six 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. Pavel Shilling subsequently improved its apparatus. He reduced the number of connecting wires from eight to two.
On October 21, 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 kilometres (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.[8] Schilling was also 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.
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. In 1833 they installed a 1,200 metres (3,900 ft) long 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, they 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 containng 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 of Göttingen University.
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.
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 Morse telegraph. Alter demonstrated it to witnesses but never developed the idea into a practical system.[9] 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."
The first commercial electrical telegraph was co-developed by Sir William Fothergill Cooke and Charles Wheatstone. Cooke and Wheatstone patented it in May 1837 as an alarm system, and it was first successfully demonstrated on 25 July 1837 between Euston and Camden Town in London.[10] 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.[11] 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.[12]
In the United States, the telegraph was developed by Samuel Morse and Alfred Vail.[13] Samuel F. B. Morse independently developed an electrical telegraph in 1836,[10] an alternative design that was capable of transmitting over long distances using poor quality wire. His assistant, Alfred Vail, developed the Morse code signaling alphabet with Morse.
On 6 January 1838 Morse first successfully tested the device at the Speedwell Ironworks near Morristown, New Jersey,[14] 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 1 May 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.[15] 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 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).
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, but 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 teleprinters 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?"[16]
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 of 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." [17] 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.
As the transcontinental telegraph was laid it passed through Nebraska where Republican sympathizers prior to the 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 31 October, just eight days before the election on 7 November 1864.
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Submarine transatlantic cables installed in 1857 and 1858 operated for only a few days or weeks before they failed. This drove the study of underwater telegraph cables and accelerated interest in mathematical analysis of electromagnetic transmission lines. The first successful transatlantic telegraph cable was completed on 27 July 1866. The lasting connections were achieved by the ship SS Great Eastern, captained by Sir James Anderson.[18]
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 had originally been awarded to him in 1864, for his insulator design. Brooks' patents allowed the Central Pacific to communicate more easily with construction crews building the First Transcontinental Railroad in America; news of the completion of the railroad was broadcast by telegraph on 10 May 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 9 August 1892, when Thomas Edison received a patent for a two-way telegraph (U.S. Patent 0,480,567, "Duplex Telegraph").
The miles of American telegraph grew from 40 in 1846 to 12,000 in 1850 to 23,000 in 1852. In Europe it increased from 2,000 in 1849 to 110,000 in 1869. The cost of sending 10 words was $1.55 in 1850, $1 in 1870, ¢40 in 1890. Within 29 years of its first installation at Euston Station, the telegraph network crossed[19] 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 to a decisively higher degree than before, particularly in trade.[20] Regarding information about events at significant distances, the telegraph for the first time allowed one to be informed about what had happened before this sank down into the realm of the historic. 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.[21]
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 at the distant source of the news and to deliver it to the telegraph office.[22] 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, 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.[22]
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 the Internet. Telegraphy allowed applications such as message routing, social networking (between Morse operators—with gossiping and even marriages among operators being 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 Edison), and many others. These points of comparisons have spurred modern commentators, such as Tom Standage, to refer to the 19th Century telegraphic network as the "Victorian Internet".
In the United States, Western Union discontinued all telegram and commercial messaging services on 27 January 2006[23], although it still offered its electronic money transfer services.
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