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North Foreland
North Foreland is a chalk headland on the Kent coast of southeast England, specifically in Broadstairs. With the rest of Broadstairs and part of Ramsgate it is the eastern side of Kent's largest peninsula, the Isle of Thanet. It presents a bold cliff to the sea, and commands views over the southern North Sea. Lighthouse Early history There was probably some sort of a beacon at an earlier period but the first distinct intimation concerning a lighthouse on the North Foreland is in the year 1636 when Charles I by letters-patent granted to Sir John Meldrum licence to continue and renew the lighthouses erected on the North and South Forelands. It seems that the lighthouse erected by Sir John consisted merely of a house built with timber lath and plaster on the top of which a light was kept in a large glass lantern for the purpose of directing ships in their course. This house was burnt down by accident in the year 1683 after which for some years use was made of a sort of bea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isle Of Thanet
The Isle of Thanet () is a peninsula forming the easternmost part of Kent, England. While in the past it was separated from the mainland by the Wantsum Channel, it is no longer an island. Archaeological remains testify to its settlement in ancient times. Today, it is a tourist destination, and has an active agricultural base. Etymology The island of Thanet is mentioned as ''Tonetic'' (c. AD 150; the TON- of this form was misread as TOΛI-, hence it appears as ''Toliatis'' in the surviving manuscripts of Ptolemy); ''Tanat's'' (3rd C AD, Solinus); ''Tanatos'' (AD 731); ''Tenid'' in 679BEAUREPAIRE and ''Tenet'' (e.g. charters of AD 679, 689 and thereafter); and the Old Welsh forms ''Tanet'' and ''Danet'', found in the ''Historia Brittonum'' (c. AD 829/30) and Armes Prydein (c. AD 930). Standard reference works for English place-names (such as Eilert Ekwall's ''Concise Oxford Dictionary of English Place-Names'') state the name ''Tanet'' is known to be Brythonic in origin. Common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convex Lenses
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), usually arranged along a common axis. Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called lenses, such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses. Lenses are used in various imaging devices like telescopes, binoculars and cameras. They are also used as visual aids in glasses to correct defects of vision such as myopia and hypermetropia. History The word ''lens'' comes from '' lēns'', the Latin name of the lentil (a seed of a lentil plant), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cantilevered
A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilever can be formed as a beam, plate, truss, or slab. When subjected to a structural load at its far, unsupported end, the cantilever carries the load to the support where it applies a shear stress and a bending moment. Cantilever construction allows overhanging structures without additional support. In bridges, towers, and buildings Cantilevers are widely found in construction, notably in cantilever bridges and balconies (see corbel). In cantilever bridges, the cantilevers are usually built as pairs, with each cantilever used to support one end of a central section. The Forth Bridge in Scotland is an example of a cantilever truss bridge. A cantilever in a traditionally timber framed building is called a jetty or forebay. In the south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Foreland Lighthouse About 1880
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is related to the Old High German ''nord'', both descending from the Proto-Indo-European unit *''ner-'', meaning "left; below" as north is to left when facing the rising sun. Similarly, the other cardinal directions are also related to the sun's position. The Latin word ''borealis'' comes from the Greek '' boreas'' "north wind, north", which, according to Ovid, was personified as the wind-god Boreas, the father of Calais and Zetes. ''Septentrionalis'' is from ''septentriones'', "the seven plow oxen", a name of ''Ursa Major''. The Greek ἀρκτικός (''arktikós'') is named for the same constellation, and is the source of the English word ''Arctic''. Other languages have other derivations. For example, in Lezgian, ''kefer'' can mean b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick Hale Holmes
Frederick Hale Holmes (born 1812) was a professor of Chemistry at the Royal Panopticon of Science and Art and pioneer of electric lighting. Career In 1853 he demonstrated the ability of electro-magnetic generators to provide continuous current to power arc lighting and in 1856 patented a magneto to power an arc light for lighthouses which he demonstrated to Michael Faraday at Blackwall in 1857. His experiments with alternating current arc lighting at South Foreland Lighthouse in 1857-60 were the subject of a lecture by Michael Faraday at the Royal Institution. One of Holmes' generators built in 1867 and used at Souter Lighthouse Souter Lighthouse is a lighthouse located in the village of Whitburn, Tyne and Wear, England. (It was generally known as Souter Point Lighthouse when in service). Souter Point was the first lighthouse in the world to be actually designed and bu ... is displayed at the Science Museum, London. References {{Reflist 1812 births Lighting engineers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margate
Margate is a seaside town on the north coast of Kent in south-east England. The town is estimated to be 1.5 miles long, north-east of Canterbury and includes Cliftonville, Garlinge, Palm Bay and Westbrook. The town has been a significant maritime port since the Middle Ages, and was associated with Dover as part of the Cinque Ports in the 15th century. It became a popular place for holidaymakers in the 18th century, owing to easy access via the Thames, and later with the arrival of the railways. Popular landmarks include the sandy beaches and the Dreamland amusement park. During the late 20th century, the town went into decline along with other British seaside resorts, but attempts are being made to revitalise the economy. History Margate was listed in the Domesday Book of 1086 as lying within the hundred of Thanet and the county of Kent. Margate was recorded as "Meregate" in 1264 and as "Margate" in 1299, but the spelling continued to vary into modern times. The name i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sector Light
A sector light is a man-made pilotage and position fixing aid that consists of strictly delineated horizontal angle light beams to guide water-borne traffic through a safe channel at night in reasonable visibility. Sector lights are most often used for safe passage through shallow or dangerous waters. This may be when leaving or entering harbour. Nautical charts (paper and electronic) give all the required information. Sectors of colored glass (or plastic) are placed in the lanterns of these lights. The light will then show these colors when observed certain bearings. Bearings referring to a sector are given in degrees true, as observed from sea. Though the colors of the light will change, the characteristics will not. The change of color is not abrupt. The transition is made through an arc of uncertainty of 2° or greater. The colors that are used, are conform to the IALA Maritime Buoyage system that is designed by the International Association of Lighthouse Authorities: * whit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catoptric
Catoptrics (from grc-gre, κατοπτρικός ''katoptrikós'', "specular", from grc-gre, κάτοπτρον ''katoptron'' "mirror") deals with the phenomena of reflected light and image-forming optical systems using mirrors. A catoptric system is also called a ''catopter'' (''catoptre''). Ancient texts ''Catoptrics'' is the title of two texts from ancient Greece: *The Pseudo-Euclidean ''Catoptrics''. This book is attributed to Euclid, although the contents are a mixture of work dating from Euclid's time together with work which dates to the Roman period., accessed 31 January 2013 It has been argued that the book may have been compiled by the 4th century mathematician Theon of Alexandria. The book covers the mathematical theory of mirrors, particularly the images formed by plane and spherical concave mirrors. *Hero's ''Catoptrics''. Written by Hero of Alexandria, this work concerns the practical application of mirrors for visual effects. In the Middle Ages, this work was fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catadioptric
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses ( dioptrics) and curved mirrors ( catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric", such as surveillance catadioptric sensors. Early catadioptric systems Catadioptric combinations have been used for many early optical systems. In the 1820s, Augustin-Jean Fresnel developed several catadioptric lighthouse reflectors. Léon Foucault developed a catadioptric microscope in 1859 to counteract aberrations of using a lens to image objects at high power. In 1876 a French engineer, A. Mangin, invented what has come to be called the Mangin mirror, a concave glass reflector with the silver surface on the rear side of the glass. The two s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresnel Lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships." The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The '' catadioptric'' form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source and add it to the beam of a lighthouse, making the light visible from greater distances. Description The Fresnel len ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Norris (engineer)
Henry Norris (1816–1878) was a British civil engineer born in Poplar, London, the son of several generations of house carpenters. He was the resident engineer for lighthouse construction projects under contract to Trinity House from civil engineers James Walker (engineer), Messrs. Walker & Burges, the firm of James Walker (engineer), James Walker and Alfred Burges, and later on oversaw the building of Souter Lighthouse, the world's first lighthouse specifically designed & built to be powered by electricity. He died at Stratford, London and is buried at Tower Hamlets Cemetery. His grave was located during ground clearing work in 2013 a few metres from that of John Buckley (VC). Henry Norris noted projects around the coast of England and Wales, included: Projects *Eddystone Lighthouse repairs to Smeaton's Tower in 1841 "The Eddystone Lighthouse has within the past few months undergone a complete renovation, under the direction of Mr. Henry Norris, engineer, from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glazing Bar
A muntin (US), muntin bar, glazing bar (UK), or sash bar is a strip of wood or metal separating and holding panes of glass in a window. Muntins can be found in doors, windows, and furniture, typically in Western styles of architecture. Muntins divide a single window sash or casement into a grid system of small panes of glass, called "lights" or "lites". In UK use, a muntin is a vertical member in timber panelling or a door separating two panels. Windows with "true divided lights" make use of thin muntins, typically 1/2" to 7/8" wide in residential windows, positioned between individual panes of glass. In wooden windows, a fillet is cut into the outer edge of the muntin to hold the pane of glass in the opening, and putty or thin strips of wood or metal are then used to hold the glass in place. The inner sides of wooden muntins are typically milled to traditional profiles. In the US, the thickness of window muntins has varied historically, ranging from very slim in 19th centur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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