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John Hood (inventor)
John Hood (1720–c.1783) was an Irish surveyor and inventor, born in Moyle, County Donegal. Works In 1772 was published in Dublin Hood's ''Tables of Difference of Latitude and Departure for Navigators, Land Surveyors''. In it he recommended that in surveying the bearing of objects should be taken from the meridian of the place. The tables printed in the book are the natural sines of all the angles, in degrees and quarter degrees, to different radii, the latter ranging from 1 to 100, as being best adapted to Gunter's chain. Hood also gave an account of the diurnal variation of the magnetic needle and its correction, and a description of a new surveying instrument. This invention was elsewhere called Hood's compass theodolite, and is described as the basis of theodolites later used in Britain and America. He is also said to have anticipated the invention of Hadley's quadrant The octant, also called a reflecting quadrant, is a reflecting instrument used in navigation. Etymolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
County Donegal
County Donegal ( ; ga, Contae Dhún na nGall) is a county of Ireland in the province of Ulster and in the Northern and Western Region. It is named after the town of Donegal in the south of the county. It has also been known as County Tyrconnell (), after the historic territory of the same name, on which it was based. Donegal County Council is the local council and Lifford the county town. The population was 166,321 at the 2022 census. Name County Donegal is named after the town of Donegal () in the south of the county. It has also been known by the alternative name County Tyrconnell, Tirconnell or Tirconaill (, meaning 'Land of Conall'). The latter was its official name between 1922 and 1927. This is in reference to the kingdom of Tír Chonaill and the earldom that succeeded it, which the county was based on. History County Donegal was the home of the once-mighty Clann Dálaigh, whose best-known branch was the Clann Ó Domhnaill, better known in English as the O'Don ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunter's Chain
Gunter's chain (also known as Gunter’s measurement) is a distance measuring device used for surveying. It was designed and introduced in 1620 by English clergyman and mathematician Edmund Gunter (1581–1626). It enabled plots of land to be accurately surveyed and plotted, for legal and commercial purposes. Gunter developed an actual measuring chain of 100 links. These, the chain and the link, became statutory measures in England and subsequently the British Empire. Description The chain is divided into 100 links, usually marked off into groups of 10 by brass rings or tags which simplify intermediate measurement. Each link is thus long. A quarter chain, or 25 links, measures and thus measures a rod (or pole). Ten chains measure a furlong and 80 chains measure a statute mile. Gunter's chain reconciled two seemingly incompatible systems: the traditional English land measurements, based on the number four, and decimals based on the number 10. Since an acre measured 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadley's Quadrant
The octant, also called a reflecting quadrant, is a reflecting instrument used in navigation. Etymology The name ''octant'' derives from the Latin ''octans'' meaning ''eighth part of a circle'', because the instrument's arc is one eighth of a circle. ''Reflecting quadrant'' derives from the instrument using mirrors to reflect the path of light to the observer and, in doing so, doubles the angle measured. This allows the instrument to use a one-eighth of a turn to measure a quarter- turn or quadrant. Origin of the octant Newton's reflecting quadrant Isaac Newton's reflecting quadrant was invented around 1699. A detailed description of the instrument was given to Edmond Halley, but the description was not published until after Halley's death in 1742. It is not known why Halley did not publish the information during his life, as this prevented Newton from getting the credit for the invention that is generally given to John Hadley and Thomas Godfrey. One copy of this inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1720 Births
Seventeen or 17 may refer to: *17 (number), the natural number following 16 and preceding 18 * one of the years 17 BC, AD 17, 1917, 2017 Literature Magazines * ''Seventeen'' (American magazine), an American magazine * ''Seventeen'' (Japanese magazine), a Japanese magazine Novels * ''Seventeen'' (Tarkington novel), a 1916 novel by Booth Tarkington *''Seventeen'' (''Sebuntiin''), a 1961 novel by Kenzaburō Ōe * ''Seventeen'' (Serafin novel), a 2004 novel by Shan Serafin Stage and screen Film * ''Seventeen'' (1916 film), an American silent comedy film *''Number Seventeen'', a 1932 film directed by Alfred Hitchcock * ''Seventeen'' (1940 film), an American comedy film *''Eric Soya's '17''' (Danish: ''Sytten''), a 1965 Danish comedy film * ''Seventeen'' (1985 film), a documentary film * ''17 Again'' (film), a 2009 film whose working title was ''17'' * ''Seventeen'' (2019 film), a Spanish drama film Television * ''Seventeen'' (TV drama), a 1994 UK dramatic short starring Christ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1780s Deaths
Year 178 ( CLXXVIII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Scipio and Rufus (or, less frequently, year 931 '' Ab urbe condita''). The denomination 178 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Bruttia Crispina marries Commodus, and receives the title of '' Augusta''. * Emperor Marcus Aurelius and his son Commodus arrive at Carnuntum in Pannonia, and travel to the Danube to fight against the Marcomanni. Asia * Last (7th) year of ''Xiping'' era and start of ''Guanghe'' era of the Chinese Han Dynasty. * In India, the decline of the Kushan Empire begins. The Sassanides take over Central Asia. Religion * The Montanist heresy is condemned for the first time. Births * Lü Meng, Chinese general (d. 220) * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
18th-century Irish People
The 18th century lasted from January 1, 1701 ( MDCCI) to December 31, 1800 ( MDCCC). During the 18th century, elements of Enlightenment thinking culminated in the American, French, and Haitian Revolutions. During the century, slave trading and human trafficking expanded across the shores of the Atlantic, while declining in Russia, China, and Korea. Revolutions began to challenge the legitimacy of monarchical and aristocratic power structures, including the structures and beliefs that supported slavery. The Industrial Revolution began during mid-century, leading to radical changes in human society and the environment. Western historians have occasionally defined the 18th century otherwise for the purposes of their work. For example, the "short" 18th century may be defined as 1715–1789, denoting the period of time between the death of Louis XIV of France and the start of the French Revolution, with an emphasis on directly interconnected events. To historians who expand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irish Surveyors
Irish may refer to: Common meanings * Someone or something of, from, or related to: ** Ireland, an island situated off the north-western coast of continental Europe ***Éire, Irish language name for the isle ** Northern Ireland, a constituent unit of the United Kingdom of Great Britain and Northern Ireland ** Republic of Ireland, a sovereign state * Irish language, a Celtic Goidelic language of the Indo-European language family spoken in Ireland * Irish people, people of Irish ethnicity, people born in Ireland and people who hold Irish citizenship Places * Irish Creek (Kansas), a stream in Kansas * Irish Creek (South Dakota), a stream in South Dakota * Irish Lake, Watonwan County, Minnesota * Irish Sea, the body of water which separates the islands of Ireland and Great Britain People * Irish (surname), a list of people * William Irish, pseudonym of American writer Cornell Woolrich (1903–1968) * Irish Bob Murphy, Irish-American boxer Edwin Lee Conarty (1922–1961) * Irish McCal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irish Inventors
Irish may refer to: Common meanings * Someone or something of, from, or related to: ** Ireland, an island situated off the north-western coast of continental Europe ***Éire, Irish language name for the isle ** Northern Ireland, a constituent unit of the United Kingdom of Great Britain and Northern Ireland ** Republic of Ireland, a sovereign state * Irish language, a Celtic Goidelic language of the Indo-European language family spoken in Ireland * Irish people, people of Irish ethnicity, people born in Ireland and people who hold Irish citizenship Places * Irish Creek (Kansas), a stream in Kansas * Irish Creek (South Dakota), a stream in South Dakota * Irish Lake, Watonwan County, Minnesota * Irish Sea, the body of water which separates the islands of Ireland and Great Britain People * Irish (surname), a list of people * William Irish, pseudonym of American writer Cornell Woolrich (1903–1968) * Irish Bob Murphy, Irish-American boxer Edwin Lee Conarty (1922–1961) * Irish McCal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
