Hydraulic telegraph

Last updated
An ancient hydraulic telegraph being used by Aeneas to send a message. Greek Hydraulic Telegraph of Aeneas relief.jpg
An ancient hydraulic telegraph being used by Aeneas to send a message.

A hydraulic telegraph (Greek : υδραυλικός τηλέγραφος) is either of two different hydraulic-telegraph telecommunication systems. The earliest one was developed in 4th-century BC Greece, while the other was developed in 19th-century AD Britain. The Greek system was deployed in combination with semaphoric fires, while the latter British system was operated purely by hydraulic fluid pressure.

Greek language Language spoken in Greece, Cyprus and Southern Albania

Greek is an independent branch of the Indo-European family of languages, native to Greece, Cyprus and other parts of the Eastern Mediterranean and the Black Sea. It has the longest documented history of any living Indo-European language, spanning more than 3000 years of written records. Its writing system has been the Greek alphabet for the major part of its history; other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems.

Telecommunication Transmission of information between locations using electromagnetics

Telecommunication is the transmission of signs, signals, messages, words, writings, images and sounds or information of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology. It is transmitted through a transmission media, such as over physical media, for example, over electrical cable, or via electromagnetic radiation through space such as radio or light. Such transmission paths are often divided into communication channels which afford the advantages of multiplexing. Since the Latin term communicatio is considered the social process of information exchange, the term telecommunications is often used in its plural form because it involves many different technologies.

Ancient Greece Civilization belonging to an early period of Greek history

Ancient Greece was a civilization belonging to a period of Greek history from the Greek Dark Ages of the 12th–9th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Roughly three centuries after the Late Bronze Age collapse of Mycenaean Greece, Greek urban poleis began to form in the 8th century BC, ushering in the Archaic period and colonization of the Mediterranean Basin. This was followed by the period of Classical Greece, an era that began with the Greco-Persian Wars, lasting from the 5th to 4th centuries BC. Due to the conquests by Alexander the Great of Macedon, Hellenistic civilization flourished from Central Asia to the western end of the Mediterranean Sea. The Hellenistic period came to an end with the conquests and annexations of the eastern Mediterranean world by the Roman Republic, which established the Roman province of Macedonia in Roman Greece, and later the province of Achaea during the Roman Empire.

Contents

Although both systems employed water in their sending and receiver devices, their transmission media were completely different. The ancient Greek system transmitted its semaphoric information to the receiver visually, which limited its use to line-of-sight distances in good visibility weather conditions only. The 19th-century British system used water-filled pipes to effect changes to the water level in the receiver unit (similar to a transparent water-filled flexible tube used as a level indicator), thus limiting its range to the hydraulic pressure that could be generated at the transmitter's device. [1]

While the Greek device was extremely limited in the codes (and hence the information) it could convey, the British device was never deployed in operation other than for very short-distance demonstrations. [1] The British device could, however, be used in any visibility within its range of operation so long as its conduits, if unheated, did not freeze in sub-zero temperatures —which contributed to its impracticality.

Greek hydraulic semaphore system

Reconstruction, Thessaloniki Science Center and Technology Museum Hydraulic telegraph, 4th century BC (reconstruction).jpg
Reconstruction, Thessaloniki Science Center and Technology Museum
Reconstructed model, messages attached to rod, Thessaloniki Science Center and Technology Museum Hydraulic telegraph messages, 4th century BC (reconstruction).jpg
Reconstructed model, messages attached to rod, Thessaloniki Science Center and Technology Museum

The ancient Greek design was described in the 4th century BC by Aeneas Tacticus and the 3rd century BC by the historian Polybius. According to Polybius, it was used during the First Punic War to send messages between Sicily and Carthage.

Aeneas Tacticus was one of the earliest Greek writers on the art of war and is credited as the first author to provide a complete guide to securing military communications. Polybius described his design for a hydraulic semaphore system.

Polybius Ancient Greek historian

Polybius was a Greek historian of the Hellenistic period noted for his work The Histories, which covered the period of 264–146 BC in detail. The work describes the rise of the Roman Republic to the status of dominance in the ancient Mediterranean world and includes his eyewitness account of the Sack of Carthage and Corinth in 146 BC, and the Roman annexation of the mainland Greece after the Achaean War.

First Punic War First war between the Roman Republic and Carthage, fought between 264 and 241 BCE

The First Punic War was the first of three wars fought between Ancient Carthage and the Roman Republic, the two great powers of the Western Mediterranean. For 23 years, in the longest continuous conflict and greatest naval war of antiquity, the two powers struggled for supremacy, primarily on the Mediterranean island of Sicily and its surrounding waters, and also in North Africa.

The system involved identical containers on separate hills, which are not connected to each other; each container would be filled with water, and a vertical rod floated within it. The rods were inscribed with various predetermined codes at various points along its height.

Code method to represent information for various purposes (storage, transmission, protection against unauthorized access, ...)

In communications and information processing, code is a system of rules to convert information—such as a letter, word, sound, image, or gesture—into another form or representation, sometimes shortened or secret, for communication through a communication channel or storage in a storage medium. An early example is the invention of language, which enabled a person, through speech, to communicate what they saw, heard, felt, or thought to others. But speech limits the range of communication to the distance a voice can carry, and limits the audience to those present when the speech is uttered. The invention of writing, which converted spoken language into visual symbols, extended the range of communication across space and time.

To send a message, the sending operator would use a torch to signal the receiving operator; once the two were synchronized, they would simultaneously open the spigots at the bottom of their containers. Water would drain out until the water level reached the desired code, at which point the sender would lower his torch, and the operators would simultaneously close their spigots. Thus the length of time the sender's torch was visible could be correlated with specific predetermined codes and messages.

A contemporary description of the ancient telegraphic method was provided by Polybius. In The Histories, Polybius wrote: [2]

British hydraulic semaphore system

The British civil engineer Francis Whishaw, who later became a principal in the General Telegraph Company, publicized a hydraulic telegraph in 1838 but was unable to deploy it commercially. [3] By applying pressure at a transmitter device connected to a water-filled pipe which travelled all the way to a similar receiver device, he was able to effect a change in the water level which would then indicate coded information to the receiver's operator. [1] [4]

The system was estimated to cost £200 per mile (1.6 km) and could convey a vocabulary of 12,000 words. [5] The U.K.'s Mechanics Magazine in March 1838 described it as follows: [6]

The article concluded speculatively that the "... hydraulic telegraph may supersede the semaphore and the galvanic telegraph". [1]

See also

Related Research Articles

Baudot code Pioneering five-bit character encodings

The Baudot code[bodo], invented by Émile Baudot, is a character set predating EBCDIC and ASCII. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of five bits, sent over a communication channel such as a telegraph wire or a radio signal. The symbol rate measurement is known as baud, and is derived from the same name.

Electrical telegraph A telegraph is a form o communication in the 1830s

An electrical telegraph was a point-to-point text messaging system, used from about the 1840s to the 1950s. It used coded pulses of electric current through dedicated wires to transmit information long distances. It was the the first electrical telecommunications system, the most widely used of a number of early messaging systems called telegraphs, devised to send text messages more rapidly than written messages could be sent.

Letter (message) written message on paper containing information sent from one party to another

A letter is a written message conveyed from one party to another party through a medium. Letters can be formal and informal. Besides a means of communication and a store of information, letter writing has played a role in the reproduction of writing as an art throughout history. Letters have been sent since antiquity and are mentioned in the Iliad. Historians Herodotus and Thucydides mention and utilize letters in their writings.

Telegraphy long distance transmission of textual/symbolic messages without the physical exchange of an object

Telegraphy is the long-distance transmission of textual messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined and such systems are thus not true telegraphs.

Wireless telegraphy

Wireless telegraphy means transmission of telegraph signals by radio waves; a more specific term for this is radiotelegraphy. Before about 1910 when radio became dominant, the term wireless telegraphy was also used for various other experimental technologies for transmitting telegraph signals without wires, such as electromagnetic induction, and ground conduction telegraph systems.

Semaphore telegraph Communication along a chain of towers using mechanically operated paddles or shutters

A semaphore telegraph is an early 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 5–20 miles (8.0–32.2 km). 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 and the heliograph.

Optical communication communication at a distance using light to carry information

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.

Pulse-position modulation (PPM) is a form of signal modulation in which M message bits are encoded by transmitting a single pulse in one of possible required time shifts. This is repeated every T seconds, such that the transmitted bit rate is bits per second. It is primarily useful for optical communications systems, which tend to have little or no multipath interference.

Radio control

Radio control is the use of control signals transmitted by radio to remotely control a device. Examples of simple radio control systems are garage door openers and keyless entry systems for vehicles, in which a small handheld radio transmitter unlocks or opens doors. Radio control is also used for control of model vehicles from a hand-held radio transmitter. Industrial, military, and scientific research organizations make use of radio-controlled vehicles as well. A rapidly growing application is control of unmanned aerial vehicles for both civilian and military uses, although these have more sophisticated control systems than traditional applications.

Multimedia Messaging Service (MMS) is a standard way to send messages that include multimedia content to and from a mobile phone over a cellular network. Users and providers may refer to such a message as a PXT, a picture message, or a multimedia message. The MMS standard extends the core SMS capability, allowing the exchange of text messages greater than 160 characters in length. Unlike text-only SMS, MMS can deliver a variety of media, including up to forty seconds of video, one image, a slideshow of multiple images, or audio.

Telegraph sounder

A telegraph sounder is an antique electromechanical device used as a receiver on electrical telegraph lines during the 19th century. It was invented by Alfred Vail after 1850 to replace the previous receiving device, the cumbersome Morse register and was the first practical application of the electromagnet. When a telegraph message comes in it produces an audible "clicking" sound representing the short and long keypresses – "dots" and "dashes" – which are used to represent text characters in Morse code. A telegraph operator would translate the sounds into characters representing the telegraph message.

In cryptography, the Polybius square, also known as the Polybius checkerboard, is a device invented by the Ancient Greeks Cleoxenus and Democleitus, and perfected by the Ancient Greek historian and scholar Polybius, for fractionating plaintext characters so that they can be represented by a smaller set of symbols.

Wire transfer, bank transfer or credit transfer is a method of electronic funds transfer from one person or entity to another. A wire transfer can be made from one bank account to another bank account or through a transfer of cash at a cash office.

XMODEM is a simple file transfer protocol developed as a quick hack by Ward Christensen for use in his 1977 MODEM.ASM terminal program. It allowed users to transmit files between their computers when both sides used MODEM. Keith Petersen made a minor update to always turn on "quiet mode", and called the result XMODEM.

History of telecommunication aspect of history relating to telecommunications

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.

Telegraph is any apparatus or process to convey messages over long distances with no intermediary messenger.

ACP-131 is the controlling publication for the listing of Q codes and Z codes. It is published by the Combined Communications Electronics Board (CCEB) countries, and revised from time to time. When the meanings of the codes contained in ACP-131 are translated into various languages, the codes provide a means of communicating between ships of various nations, such as during a NATO exercise, when a common language is not in effect.

Phryctoria was a means of communication used in Ancient Greece.

Flag semaphore Telegraphy system conveying information at a distance by means of visual signals

Flag semaphore is the telegraphy system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used in the maritime world in the 19th century. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or using lighted wands instead of flags, at night.

Telex switched network of teleprinters

The telex network was a public switched network of teleprinters similar to a telephone network, for the purposes of sending text-based messages. Telex was a major method of sending written messages electronically between businesses in the post-World War II period. Its usage went into decline as the fax machine grew in popularity in the 1980s.

References

  1. 1 2 3 4 Distant Writing: A History of the Telegraph Companies in Britain between 1838 and 1868 - Non-Competitors, Distantwriting.co.uk website. Retrieved 2009-07-14
  2. Lahanas, Michael, Ancient Greek Communication Methods Archived 2014-11-02 at the Wayback Machine , Mlahanas.de website. Retrieved 2009-07-14.
  3. Herapath, John. The Railway Magazine and Annals of Science, Vol. V.: Hydraulic Telegraph (section), London, Charing-Cross East: Wyld and Son, 1839, pp. 9–11.
  4. Whishaw, Francis. "Report of the Annual Meeting of the British Association for the Advancement of Science, Volume 18, Parts 1848–1849: On The Uniformity Of Time And Other Telegraphs", British Association for the Advancement of Science London: John Murray, 1849, p. 123.
  5. The Civil Engineer and Architect's Journal, Volume 1: Oct. 1837 to Dec. 1838: Miscellany, London: William Laxton, 1838, p. 88.
  6. Roberts, Steven. A History of Telegraph Companies In Britain Between 1838 And 1868: Whishaw's Hydraulic Telegraph, retrieved from DistantWriting.co.uk website January 8, 2013.