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Heliograph
A heliograph () is a semaphore system that signals by flashes of sunlight (generally using Morse code) reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military, survey and forest protection work. Heliographs were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975. Description There were many heliograph types. Most heliographs were variants of the British Army Mance Mark V version (Fig.1). It used a mirror with a small unsilvered spot in the centre. The sender aligned the heliograph to the target by looking at the reflected target in the mirror and moving their head until the target was hidden by the unsilvered spot. Keeping their head still, they then ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliograph (1)-2
A heliograph () is a solar telegraph system that signals by flashes of sunlight (generally using Morse code) reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military, survey and forest protection work. Heliographs were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975. Description There were many heliograph types. Most heliographs were variants of the British Army Mance Mark V version (Fig.1). It used a mirror with a small unsilvered spot in the centre. The sender aligned the heliograph to the target by looking at the reflected target in the mirror and moving their head until the target was hidden by the unsilvered spot. Keeping their head still, they then ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telegraphy
Telegraphy is the long-distance transmission of 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. The earliest true telegraph put into widespread use was the optical telegraph of Claude Chappe, invented in the late 18th century. The system was used extensively in France, and European nations occupied by France, during the Napoleonic era. The electric telegraph started to replace the optical telegraph in the mid-19th century. It was first taken up in Britain in the form of the Cooke and Wheatstone telegraph, initially used mostly as an aid to railway signalling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semaphore
Semaphore (; ) is the use of an apparatus to create a visual signal transmitted over distance. A semaphore can be performed with devices including: fire, lights, flags, sunlight, and moving arms. Semaphores can be used for telegraphy when arranged in visually connected networks, or for traffic signalling such as in railway systems, or traffic lights in cities. Fire The Phryctoriae were a semaphore system used in Ancient Greece for the transmission of specific prearranged messages. Towers were built on selected mountaintops, so that one tower, the ''phryctoria'', would be visible to the next tower, usually twenty-miles distant. Flames were lit on one tower, then the next tower would light a flame in succession. The Byzantine beacon system was a semaphore developed in the 9th century during the Arab–Byzantine wars. The Byzantine Empire used a system of beacons to transmit messages from the border with the Abbasid Caliphate across Asia Minor to the Byzantine capital, C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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). Modern communication relies on optical networking systems using optical fiber, optical amplifiers, lasers, switches, routers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Norris (1721–1786)
John Norris (1721 – 29 June 1786) was an English merchant and a member of the landed gentry. He was High Sheriff of Buckinghamshire in 1775. Biography Norris' father, Robert Norris (d. 1751) was a prosperous merchant in London, but through misfortune or mismanagement he lost all his money, and ended up in Fleet Prison (a debtor's prison). Fortunately his wife, Ellen Savage, came from a very wealthy family in Bishop's Tachbrook, Warwickshire, and when her father died she inherited property and lands worth £140,000. The young Norris was educated at Eton College, and when he was 17 he matriculated at Christ Church, Oxford. He was offered a demyship at Magdalen College, Oxford, from where he gained BA and MA degrees. He later obtained a Doctor of Civil Law. On his father's death, John Norris inherited land and property in Warwickshire, Hampshire, Buckinghamshire and in Islington. He had two manors, Hawley Place in Hawley, Hampshire and Hughenden Manor in High Wycombe, Buck ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliotrope (instrument)
The heliotrope is an instrument that uses a mirror to reflect sunlight over great distances to mark the positions of participants in a land survey. The heliotrope was invented in 1821 by the German mathematician Carl Friedrich Gauss. The word "heliotrope" is taken from the Greek: ''helios'' (), meaning "sun", and '' tropos'' (), meaning "turn". Heliotropes were used in surveys from Gauss's survey in Germany in 1821 through the late 1980s, when GPS measurements replaced the use of the heliotrope in long distance surveys. Colonel Sir George Everest introduced the use of heliotropes into the Great Trigonometric Survey in India around 1831, and the US Coast and Geographic Survey used heliotropes to survey the United States. ThIndian specification for heliotropeswas updated in 1981, and the American military specification for heliotropes (MIL-H-20194E) was retired on 8 December 1995. Surveyors used the heliotrope as a specialized form of survey target; it was employed during large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morse Code
Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of the inventors of the telegraph. International Morse code encodes the 26 basic Latin letters through , one accented Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals ( prosigns). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of ''dits'' and ''dahs''. The ''dit'' duration is the basic unit of time measurement in Morse code transmission. The duration of a ''dah'' is three times the duration of a ''dit''. Each ''dit'' or ''dah'' within an encoded character is followed by a period of signal absence, called a ''space'', equal to the ''dit'' duration. The letters of a word are separated by a space of duration equal to three ''dits' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Army Signal Corps
The United States Army Signal Corps (USASC) is a branch of the United States Army that creates and manages communications and information systems for the command and control of combined arms forces. It was established in 1860, the brainchild of Major (United States)#American Civil War, Major Albert J. Myer, and had an important role in the American Civil War. Over its history, it had the initial responsibility for portfolios and new technologies that were eventually transferred to other U.S. government entities. Such responsibilities included Defense Intelligence Agency, military intelligence, National Weather Service#History, weather forecasting, and Aeronautical Division, U.S. Signal Corps, aviation. Mission statement Support for the command and control of combined arms forces. Signal support includes network operations (information assurance, information dissemination management, and network management) and management of the electromagnetic spectrum. Signal support encompasses a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Telegraphy
An optical telegraph is a line of stations, typically towers, for the purpose of conveying textual information by means of visual signals. There are two main types of such systems; the semaphore telegraph which uses pivoted indicator arms and conveys information according to the direction the indicators point, and the shutter telegraph which uses panels that can be rotated to block or pass the light from the sky behind to convey information. 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. This system is often referred to as ''semaphore'' without qualification. Lines of relay towers with a semaphore rig at the top were built within line of sight of each other, at separations of . Operators at each tower would watch the neighboring tower through a telescope, and when the semaphore arms began to move spelling out a message, they would pass the message on to the next tower. This sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Ellen (Utah)
Mount Ellen is a mountain located in Garfield County, Utah, Garfield County, Utah, United States. Description Mount Ellen's North Summit Ridge is the highest point in the Henry Mountains; it is also the highest point in Garfield County. It can be reached by a short hike from an unpaved road. These mountains were the last to be surveyed by the United States Geological Survey, USGS in the lower 48 states. The mountain can be seen from as far as Mount Peale in the La Sal Mountains of eastern Utah. Mount Ellen is an ultra prominent peak, meaning that it has more than of topographic prominence, standing out considerably from nearby mountains. It stands in the drainage basin, watershed of the Fremont River (Utah), Fremont River, which together with Muddy Creek (Utah), Muddy Creek forms the Dirty Devil River, which drains into the Colorado River, and ultimately into the Gulf of California in Mexico. The Southern Paiute, Paiute name for Mount Ellen was Un tar re. It was also referred t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holograph
An autograph or holograph is a manuscript or document written in its author's or composer's hand. The meaning of autograph as a document penned entirely by the author of its content, as opposed to a typeset document or one written by a copyist or scribe other than the author, overlaps with that of holograph. Autograph manuscripts are studied by scholars, and can become collectable objects. Holographic documents have, in some jurisdictions, a specific legal standing. Terminology According to ''The Oxford English Minidictionary'', an autograph is, apart from its meaning as a signature, a "manuscript in the author's handwriting," while a holograph is a "(document) written wholly in the handwriting of the person in whose name it appears." In the 1911 edition of the ''Encyclopædia Britannica'', Edward Maunde Thompson gives two common meanings of the word autograph as it applies to documents: "a document signed by the person from whom it emanates" and "one written entirely in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herodotus
Herodotus ( ; grc, , }; BC) was an ancient Greek historian and geographer from the Greek city of Halicarnassus, part of the Persian Empire (now Bodrum, Turkey) and a later citizen of Thurii in modern Calabria (Italy). He is known for having written the ''Histories'' – a detailed account of the Greco-Persian Wars. Herodotus was the first writer to perform systematic investigation of historical events. He is referred to as " The Father of History", a title conferred on him by the ancient Roman orator Cicero. The ''Histories'' primarily cover the lives of prominent kings and famous battles such as Marathon, Thermopylae, Artemisium, Salamis, Plataea, and Mycale. His work deviates from the main topics to provide a cultural, ethnographical, geographical, and historiographical background that forms an essential part of the narrative and provides readers with a wellspring of additional information. Herodotus has been criticized for his inclusion of "legends ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
