We explain what the telegraph is, how it works and why it was so important. In addition, we tell you its history and what Morse code is.
What is the telegraph?
The telegraph It is a device that allows the transmission of information over a distance, using electrical signals transmitted through cables or radio waves, and a coding system, such as Morse code, that allows these signals to be translated into words. Telegraphy, created between the 18th and 19th centuries, was the first form of electrical communication in history.
In principle, different forms of telegraphy existed over time, but the term “telegraph” is reserved for the electric telegraph, a mid-19th century invention that It was the main form of distance communication in the world for almost 100 years.
For its part, the term “telegraph” is composed of the Greek words TV (“distance”, “far”) and graphos (“writing”). It was initially used in the 18th century to name an optical communication system developed in France, which operated through light towers in the manner of traffic lights.
The telegraph revolutionized the methods used at the time to communicate over long distances, motivated a great expansion of electrical wiring in the main industrialized nations and inaugurated a specialized labor sector (telegraphers) around this type of device and electricity. (electrical engineers). It was one of the great inventions associated with the Industrial Revolution of the 19th century.
See also: Media
The invention of the telegraph
The invention of the telegraph occurred thanks to the accumulation of scientific and technological knowledge that took place in Europe and the United States between the 18th and 19th centuries, especially in the area of electricity. Particularly important were the previous contributions of the Italian scientist Alessandro Volta (1745-1827), the British Michel Faraday (1791-1867) and the American Joseph Henry (1797-1878).
The idea of telegraphic communication itself was an invention of the French mathematician and physicist André-Marie Ampère (1775-1836), who tried to create a system for transmitting electrical impulses using a series of galvanometers, but without managing to overcome the barrier of 61 meters of distance. It took the invention of the electromagnet and the relay in the 1830s for Joseph Henry to create an improved version for use in long cable runs.
At the same time, in tsarist Russia, The Russian diplomat and scientist Pavel Schilling (1786-1837) invented a telegraph that operated with a board similar to that of a piano and with which he managed to transmit electrical impulses along a cable 5 km away. This invention promoted the first experimental underground and underwater wiring in Russia, but the project was abandoned in 1837 after the death of the scientist.
Other attempts to build a telegraph were carried out by the Germans Carl Friedrich Gauss (1777-1855) and Wilhelm Eduard Weber (1804-1891), who installed a 1,200-meter power line on the roofs of the city of Göttingen and managed to transmit the electricity from the university where they worked to the city's astronomical observatory. For his part, on the other side of the Atlantic, the American David Alter (1807-1881) had similar experiences in Elderton, Pennsylvania, a year before Samuel Morse patented his famous electric telegraph.
It was after 1836 that the American Samuel Morse (1791-1872) designed a device that, among other things, consisted of an electrified pencil capable of painting a straight line on an easel in the absence of electric current and an undulating line when current was present.
But after improving the device in collaboration with his colleague Alfred Vail (1807-1859), Morse finally devised a graphic representation system that, using points and lines, could reflect electrical impulses and be translated into letters. The famous Morse code was born that way.
On May 24, 1844, Morse and Vail achieved a public demonstration of their telegraph system sending a first message from Washington, DC, to the B&O railroad in Baltimore. This first message consisted of “What has God wrought?” (“What has God brought us?”), from the book of Numbers of the biblical Old Testament.
Thereafter, the Morse-Vail telegraph It was a resounding success in the following decades and served as inspiration for future telegraphs developed throughout the 19th century, and whose final point was the invention and popularization of the teletype at the beginning of the 20th century.
How does the telegraph work?
The general operation of the electric telegraph requires:
- An emitting device that emits electrical pulses.
- A receiving artifact who receives them.
For this to happen, the transmitter has a switch (called a “manipulator”), which when closed allows the circulation of current from an electric battery to the transmission line (wired or wireless) and the electromagnet on the other side. The latter, when activated, attracts a metal piece finished in a punch, so that the paper slides over a roller and points and lines are made thanks to the movement of a cylinder filled with ink.
So, the duration of the switch pressure on the emitter results in the continuity of a line on the other side: If pressed quickly, a point is drawn; If you press longer, a line is drawn. A set of these symbols can then be translated into alphanumeric characters to obtain a short message.
Importance of the telegraph
The telegraph was a revolutionary invention in the 19th century, which For the first time in history, it allowed reciprocal, rapid and effective communication over great distances. The ability to send and receive messages quickly, with almost no delay in return, allowed the coordination of resources over great distances, which It was key to international trade and the transfer of goods, especially through trains and ships.
This also made it possible to bring together the different regions of the countries, overcome borders and inaugurate instant communication: a person could report an emergency and immediately receive a response, which would have been impossible through postal mail.
The ability to send messages without delay and 24 hours a day provided greater independence and efficiency to the military sector since intelligence could be quickly sent to the leadership of the army. This in turn made telegraph offices an important military target during the conflicts of the 20th century.
Finally, the popularization of the telegraph reaffirmed the importance of electricity and electrical engineering in the modern world, and ushered in new forms of technology both in the telecommunications sector and in other areas of engineering and physics.
morse code
Morse code owes its name to its inventor, the American Samuel Morse, and emerged as a formal language for the transmission of electrical impulses, which distinguishes between two fundamental signs: the dot (.) and the line (-) each of which corresponds to a range of duration of the electrical impulse: short and long. Thus, by recognizing the duration of the transmitted impulse, telegraphy devices could receive coded messages that were later translated into verbal language.
For the latter, the Morse code has an alphabet: each letter and number corresponds to a specific combination of short and long pulses, as follows:
TO . – (point, line) 1 . – – – – (point, line, line, line, line)
b – . (line, dot, dot, dot) 2 .- – – (dot, dot, line, line, line)
c – . -. (line, point, line, point) 3 . . – – (dot, dot, dot, line, line)
d – . (line, dot, dot) 4 …. – (dot, dot, dot, dot, line)
AND (point) 5 …. (dot, dot, dot, dot, dot)
In this way, a message like “EVERY 1” (that is, “each one”) can be translated into Morse code as follows: -.-.- -..- .—-.
The end of telegraphy
Telegraphy was in vogue throughout the world until the end of the 20th century, when it was displaced by more effective and simpler communication mechanisms. The invention in 1985 of mobile text messaging and later internet messaging made telegraphy completely obsolete. The last telegraph network in the world was closed in 2013: the Indian state company Bharat Sanchar Nigam Limited. However, telegraphy had been in minority use for decades.
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References
- “Telegraph” in Wikipedia.
- “Etymology of Telegraph” in the Online Spanish Etymological Dictionary.
- “How the telegraph revolutionized communications” (video) in Deutsche Welle en Español.
- “Findings and creations: The telegraph” (video) at UNED.
- “The telegraph” in the ILCE Digital Library (Mexico).
- “Telegraph” in The Encyclopaedia Britannica.
