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Henry Gregory (instrument Maker)
Henry Gregory (1744–1782) was an English mathematical and optical instrument maker. Gregory was apprenticed to John Fowler in 1732 and was himself in business from c. 1750–1792 from premises in Francis Court, Clerkenwell, London and an establishment known as "The Azimuth Compass" in Leadenhall Street, London. His company later became known as Gregory and Son. Gregory manufactured navigational instruments, including quadrants of the type invented by John Hadley and compasses. One of his azimuth compasses traveled with the explorer James Cook on his second voyage to the southern Pacific Ocean in 1772–1775. An azimuth compass is a compass fitted with vertical sights, used to take the magnetic azimuth of a star or planet. Surviving examples of the azimuth compass exist in the collections of the National Maritime Museum The National Maritime Museum (NMM) is a maritime museum in Greenwich, London. It is part of Royal Museums Greenwich, a network of museums ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematical Instrument
A mathematical instrument is a tool or device used in the study or practice of mathematics. In geometry, construction of various proofs was done using only a compass (drafting), compass and straightedge; arguments in these proofs relied only on idealized properties of these instruments and literal construction was regarded as only an approximation. In applied mathematics, mathematical instruments were used for measuring angles and distances, in astronomy, navigation, surveying and in the measurement of time.Gerard L'Estrange Turner ''Scientific Instruments, 1500-1900: An Introduction'' ( University of California Press, 1998) page 8 Overview Instruments such as the astrolabe, the Quadrant (instrument), quadrant, and others were used to measure and accurately record the relative positions and movements of planets and other celestial objects. The sextant and other related instruments were essential for navigation at sea. Most instruments are used within the field of geometry, incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clerkenwell
Clerkenwell () is an area of central London, England. Clerkenwell was an ancient parish from the mediaeval period onwards, and now forms the south-western part of the London Borough of Islington. The well after which it was named was rediscovered in 1924. The watchmaking and watch repairing trades were once of great importance. Geography Goswell Street formed the eastern boundary of the Clerkenwell parishes, with the River Fleet, now buried beneath Farringdon Road and other streets, forming the western boundary with Holborn and, in part, St Pancras. This western boundary with both neighbouring areas is now used as part of the London Borough of Islington’s western boundary with the London Borough of Camden. Pentonville is a part of northern Clerkenwell, while the southern part is sometimes referred to as Farringdon, after the railway station of that name – which was named after Farringdon Road (an extension of Farringdon Street) and originally named Farringdon Street S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a major settlement for two millennia. The City of London, its ancient core and financial centre, was founded by the Romans as '' Londinium'' and retains its medieval boundaries.See also: Independent city § National capitals The City of Westminster, to the west of the City of London, has for centuries hosted the national government and parliament. Since the 19th century, the name "London" has also referred to the metropolis around this core, historically split between the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which largely comprises Greater London, governed by the Greater London Authority.The Greater London Authority consists of the Mayor of London and the London Assembly. The London Mayor is distinguished fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leadenhall Street
__NOTOC__ Leadenhall Street () is a street in the City of London. It is about and links Cornhill, London, Cornhill in the west to Aldgate in the east. It was formerly the start of the A11 road (England), A11 road from London to Norwich, but that route now starts further east at Aldgate. Leadenhall Street has always been a centre of commerce. It connected the medieval market of Leaden Hall with Aldgate, the eastern gate in the Roman city wall. The East India Company had its headquarters there, as later did the Peninsular and Oriental Steam Navigation Company (P&O). By the mid 20th century, grand stone-faced offices lined the street. Today it is closely associated with the insurance industry and particularly the Lloyd’s of London, Lloyd's insurance market, with its dramatic building in the adjacent Lime Street. It forms part of a cluster of tall buildings including the 48-storey 122 Leadenhall Street, “Cheesegrater” and the 38-storey The Scalpel, “Scalpel”. Other buildi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrant (instrument)
A quadrant is an instrument used to measure angles up to 90°. Different versions of this instrument could be used to calculate various readings, such as longitude, latitude, and time of day. Its earliest recorded usage was in ancient India in Rigvedic times by Rishi Atri to observe a solar eclipse. It was then proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers. Mural quadrants were important astronomical instruments in 18th-century European observatories, establishing a use for positional astronomy. Etymology The term ''quadrant'', meaning one fourth, refers to the fact that early versions of the instrument were derived from astrolabes. The quadrant condensed the workings of the astrolabe into an area one fourth the size of the astrolabe face; it was essentially a quarter of an astrolabe. History During Rigvedic times in ancient India, quadrants called 'Tureeyam's were used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Hadley
John Hadley (16 April 1682 – 14 February 1744) was an English mathematician, and laid claim to the invention of the octant, two years after Thomas Godfrey claimed the same. Biography He was born in Bloomsbury, London the eldest son of George Hadley of Osidge, East Barnet, Hertfordshire and his wife Katherine FitzJames. His younger brother George Hadley became a noted meteorologist. In 1717 John became a member (and later vice-president) of the Royal Society of London. In 1729 he inherited his father's East Barnet estate. He died in East Barnet in 1744 and is buried in the local churchyard with other members of his family. He had married Elizabeth, daughter of Thomas Hodges, FRS (former Attorney General of Barbados) and had one child, a son and heir John, born in 1738. Work In 1730 Hadley invented the reflecting octant, which could be used to measure the altitude of the sun or other celestial objects above the horizon at sea. A mobile arm carrying a mirror and pivotin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compass
A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north. Other methods may be used, including gyroscopes, magnetometers, and GPS receivers. Compasses often show angles in degrees: north corresponds to 0°, and the angles increase clockwise, so east is 90°, south is 180°, and west is 270°. These numbers allow the compass to show azimuths or bearings which are commonly stated in degrees. If local variation between magnetic north and true north is known, then direction of magnetic north also gives direction of true north. Among the Four Great Inventions, the magnetic compass was first invented as a device for divination as early as the Chinese Han Dynasty (since c. 206 BC),Li Shu-hua, p. 176 and later adopted for navigation by the Song Dynasty Chinese during the 11th centur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuth Compass
An azimuth compass (or azimuthal compass) is a nautical instrument used to measure the magnetic azimuth, the angle of the arc on the horizon between the direction of the sun or some other celestial object and the magnetic north. This can be compared to the true azimuth obtained by astronomical observation to determine the magnetic declination, the amount by which the reading of a ship's compass must be adjusted to obtain an accurate reading. Azimuth compasses were important in the period before development of the reliable chronometers needed to determine a vessel's exact position from astronomical observations. Theory In navigation, the true azimuth of a heavenly body is the arc of the horizon between the point where a vertical plane containing the observer and the heavenly body intersects the horizon and the direction of true north. The magnetic azimuth is the arc between the point on the horizon below the heavenly body and the direction of magnetic north. When the latitude and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Cook
James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean and to New Zealand and Australia in particular. He made detailed maps of Newfoundland prior to making three voyages to the Pacific, during which he achieved the first recorded European contact with the eastern coastline of Australia and the Hawaiian Islands, and the first recorded circumnavigation of New Zealand. Cook joined the British merchant navy as a teenager and joined the Royal Navy in 1755. He saw action in the Seven Years' War and subsequently surveyed and mapped much of the entrance to the St. Lawrence River during the siege of Quebec, which brought him to the attention of the Admiralty and the Royal Society. This acclaim came at a crucial moment for the direction of British overseas exploration, and it led to his commission in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, larger than Earth's entire land area combined .Pacific Ocean . '' Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the |
National Maritime Museum
The National Maritime Museum (NMM) is a maritime museum in Greenwich, London. It is part of Royal Museums Greenwich, a network of museums in the Maritime Greenwich World Heritage Site. Like other publicly funded national museums in the United Kingdom, it has no general admission charge; there are admission charges for most side-gallery temporary exhibitions, usually supplemented by many loaned works from other museums. Creation and official opening The museum was created by the National Maritime Museum Act 1934 under a Board of Trustees, appointed by HM Treasury. It is based on the generous donations of Sir James Caird (1864–1954). King George VI formally opened the museum on 27 April 1937 when his daughter Princess Elizabeth accompanied him for the journey along the Thames from London. The first director was Sir Geoffrey Callender. Collection Since the earliest times Greenwich has had associations with the sea and navigation. It was a landing place for the Romans, Henry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Museum Of American History
The National Museum of American History: Kenneth E. Behring Center collects, preserves, and displays the heritage of the United States in the areas of social, political, cultural, scientific, and military history. Among the items on display is the original Star-Spangled Banner (flag), Star-Spangled Banner. The museum is part of the Smithsonian Institution and located on the National Mall at 14th Street (Washington, D.C.), 14th Street and Constitution Avenue NW in Washington, D.C. History The museum opened in 1964 as the Museum of History and Technology. It was one of the last structures designed by the renowned architectural firm McKim Mead & White. In 1980, the museum was renamed the National Museum of American History to represent its mission of the collection, care, study, and interpretation of objects that reflect the experience of the American people. The museum site had previously held two Temporary buildings of the National Mall, temporary war buildings constructed in 194 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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