38-594: 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, 15 miles north of South Foreland , and commands views over the southern North Sea . LB&SCR H2 class 4-4-2 no. 422 (later no. B422, 2422, and 32422)
76-447: A phosphate mineral) is also sometimes present, as nodules or as small pellets interpreted as fecal pellets. In some chalk beds, the calcite has been converted to dolomite , CaMg(CO 3 ) 2 , and in a few cases the dolomitized chalk has been dedolomitized back to calcite. Chalk is highly porous, with typical values of porosity ranging from 35 to 47 per cent. While it is similar in appearance to both gypsum and diatomite , chalk
114-408: 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 beacon on which a light was hoisted. But near the end of the same century a strong octagonal structure of flint was erected on the top of which
152-468: A similar system in the lower lighthouse at Portland ): it consisted of two rows of nine lamps and reflectors arranged in a convex curve, placed behind a row of solid glass convex lenses which were incorporated within the glazing around the lantern room. In 1832 Trinity House purchased the North and South Foreland lighthouses from Greenwich Hospital and two years later the lenses were removed. 1858 saw
190-642: Is mined from chalk deposits both above ground and underground . Chalk mining boomed during the Industrial Revolution , due to the need for chalk products such as quicklime and bricks . Most people first encounter chalk in school where it refers to blackboard chalk , which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased. Blackboard chalk manufacturers now may use mineral chalk, other mineral sources of calcium carbonate, or
228-469: Is also used for " blackboard chalk " for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum . Chalk is a fine-textured, earthy type of limestone distinguished by its light colour, softness, and high porosity. It is composed mostly of tiny fragments of the calcite shells or skeletons of plankton , such as foraminifera or coccolithophores . These fragments mostly take
266-428: Is applied to the hands and feet to remove perspiration and reduce slipping. Chalk may also be used as a house construction material instead of brick or wattle and daub : quarried chalk was cut into blocks and used as ashlar , or loose chalk was rammed into blocks and laid in mortar. There are still houses standing which have been constructed using chalk as the main building material. Most are pre- Victorian though
304-518: Is commonly used as a drying agent to obtain better grip by gymnasts and rock climbers. Glazing putty mainly contains chalk as a filler in linseed oil . Chalk and other forms of limestone may be used for their properties as a base . Chalk is a source of quicklime by thermal decomposition , or slaked lime following quenching of quicklime with water. In agriculture , chalk is used for raising pH in soils with high acidity . Small doses of chalk can also be used as an antacid . Additionally,
342-515: Is identifiable by its hardness, fossil content, and its reaction to acid (it produces effervescence on contact). In Western Europe, chalk was formed in the Late Cretaceous Epoch and the early Palaeocene Epoch (between 100 and 61 million years ago). It was deposited on extensive continental shelves at depths between 100 and 600 metres (330 and 1,970 ft), during a time of nonseasonal (likely arid) climate that reduced
380-582: Is now usually made of talc (magnesium silicate). Chalk beds form important petroleum reservoirs in the North Sea and along the Gulf Coast of North America. In southeast England, deneholes are a notable example of ancient chalk pits. Such bell pits may also mark the sites of ancient flint mines, where the prime object was to remove flint nodules for stone tool manufacture. The surface remains at Cissbury are one such example, but perhaps
418-595: The Cretaceous Period was named for these deposits. The name Cretaceous was derived from Latin creta , meaning chalk . Some deposits of chalk were formed after the Cretaceous. The Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period. It forms the famous White Cliffs of Dover in Kent , England, as well as their counterparts of the Cap Blanc Nez on
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#1732780290783456-663: The Dover Strait and the lighthouses at Dungeness and Beachy Head ). North Foreland lighthouse was the last Trinity House manned lighthouse in the UK but was automated in a ceremony presided over by the Duke of Edinburgh in 1998. Dermot Cronin and Tony Homewood were the last Principal Lighthouse Keepers that manned North Foreland lighthouse. The actual last manned lighthouse, owned by the Lancaster Port Commission
494-706: The Netherlands to detect allied aircraft flying across the English Channel and a chain of top secret radar jamming stations were set up by British scientists along the south east coast of Britain. An array of transmitters was set out around the gallery of the lighthouse controlled by equipment in the lower lantern as part of this chain. By the late 1980s North Foreland Lighthouse was operating as an area control station, with an augmented crew of keepers monitoring (in addition to North Foreland itself) eleven other major aids to navigation (including light vessels in
532-409: The bedding or as nodules in seams , or linings to fractures , embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint). Chalk is so common in Cretaceous marine beds that
570-469: The Foreland before they could discover the light. They added that before the lantern was placed there and when the fire was kept in the open air the wind kept the fire in a constant blaze which was seen in the air far above the lighthouse. Complaints of this sort were so loud and frequent that the governors of Greenwich Hospital sent Sir John Thomson to examine and make arrangements on the subject. He ordered
608-732: The North American interior. Chalk is also found in western Egypt (Khoman Formation) and western Australia ( Miria Formation ). Chalk of Oligocene to Neogene age has been found in drill cores of rock under the Pacific Ocean at Stewart Arch in the Solomon Islands . There are layers of chalk, containing Globorotalia , in the Nicosia Formation of Cyprus , which formed during the Pliocene . Chalk
646-473: The amount of erosion from nearby exposed rock. The lack of nearby erosion explains the high purity of chalk. The coccolithophores, foraminifera, and other microscopic organisms from which the chalk came mostly form low-magnesium calcite skeletons, so the sediments were already in the form of highly stable low-magnesium calcite when deposited. This is in contrast with most other limestones, which formed from high-magnesium calcite or aragonite that rapidly converted to
684-464: The construction of a new lantern atop the lighthouse: '14 feet wide and 22 feet from the floor to the apex of the roof. It is sixteen-sided with diagonal astragals '. In it, under the supervision of engineer Henry Norris , a new multi-wick oil burner was installed together with a large ( first-order ) fixed catadioptric optic manufactured by Sautter & Co. of Paris (replacing the previous catoptric apparatus of 18 Argand lamps & reflectors); it
722-644: The cottages around the lighthouse can be rented as holiday accommodation. In electoral wards as most often drawn, postally as to post town and in the Church of England it remains part of Broadstairs. Two naval battles of the Anglo-Dutch Wars are called the Battle of the North Foreland after the cape: A coastal radio station was established adjacent to the light house in 1901. Its call sign
760-413: The exterior of the tower was rendered and painted white. This work was completed in 1866, leaving the lighthouse looking much the same as it does today. In 1880 the light characteristic was changed from fixed to occulting (being eclipsed for five seconds every half minute). The light was further improved in 1894 when a Trinity House-pattern eight-wick heavy mineral oil burner was installed in place of
798-512: The form of calcite plates ranging from 0.5 to 4 microns in size, though about 10% to 25% of a typical chalk is composed of fragments that are 10 to 100 microns in size. The larger fragments include intact plankton skeletons and skeletal fragments of larger organisms, such as molluscs , echinoderms , or bryozoans . Chalk is typically almost pure calcite, CaCO 3 , with just 2% to 4% of other minerals. These are usually quartz and clay minerals , though collophane (cryptocrystalline apatite ,
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#1732780290783836-448: The height of 100 feet including the lantern room at the top in which the lights were kept. (To prevent accidents from fire the lantern room was coated with copper as was also the gallery around it; this gallery used to be much frequented by the visitors to Margate on account of the extensive views.) At the same time oil lamps were installed in the tower, together with a new optical system designed by Thomas Rogers (who had previously installed
874-579: The lamp itself was made to flash (rather than this being effected by the rotation of a lens). The light source was a tungsten filament lamp (with an identical lamp being provided as a standby along with an acetylene lamp for emergencies, all three mounted on an automatic lamp changer ). Also in 1930 a radio beacon was established at North Foreland. During the Second World War a number of radar stations were set up by German forces in France and
912-506: The lantern to be taken away and things to be restored to nearly their former state, with the light to continue burning all the night until daylight. Towards the end of the 18th century the North Foreland Lighthouse underwent some considerable alterations and repairs. In 1792, under the supervision of John Yenn (Surveyor to Greenwich Hospital), two stories of brick were built on the original structure which raised it to
950-528: The mineral gypsum ( calcium sulfate ). While gypsum-based blackboard chalk is the lowest cost to produce, and thus widely used in the developing world , use of carbonate-based chalk produces larger particles and thus less dust, and it is marketed as "dustless chalk". Coloured chalks, pastel chalks, and sidewalk chalk (shaped into larger sticks and often coloured), used to draw on sidewalks , streets, and driveways , are primarily made of gypsum rather than calcium carbonate chalk. Magnesium carbonate chalk
988-406: The more stable low-magnesium calcite after deposition, resulting in the early cementation of such limestones. In chalk, absence of this calcium carbonate conversion process prevented early cementation, which partially accounts for chalk's high porosity. Chalk is also the only form of limestone that commonly shows signs of compaction. Flint (a type of chert ) is very common as bands parallel to
1026-562: The most famous is the extensive complex at Grimes Graves in Norfolk . Chalk was traditionally used in recreation. In field sports, such as tennis played on grass, powdered chalk was used to mark the boundary lines of the playing field or court. If a ball hits the line, a cloud of chalk or pigment dust will be visible. In recent years, powdered chalk has been replaced with titanium dioxide . In gymnastics, rock-climbing, weightlifting and tug of war , chalk — now usually magnesium carbonate —
1064-428: The night. This contrivance is said to have been for the purpose of saving coals but it would seem more probable that it was in order to preserve the fire from being extinguished by rain. However the plan did not work well and great injury resulted to navigation as many vessels were lost on the sands from not seeing the light, and so little was it visible at sea that mariners asserted that they had often in hazy weather seen
1102-438: The old oil lamp. The lamp continued to be upgraded through the first part of the twentieth century: a triple mantle burner was installed in 1904, and its place was taken by a ‘Hood’ 100mm petroleum vapour burner in 1923. Then in 1930 the light was electrified, and at the same time given the light characteristic of five flashes every twenty seconds, which it retains to the present day. The fixed optic of 1860 continued in use, so
1140-607: The other side of the Dover Strait . The Champagne region of France is mostly underlain by chalk deposits, which contain artificial caves used for wine storage . Some of the highest chalk cliffs in the world occur at Jasmund National Park in Germany and at Møns Klint in Denmark . Chalk deposits are also found in Cretaceous beds on other continents, such as the Austin Chalk , Selma Group , and Niobrara Formations of
1178-532: The sea by the compression of microscopic plankton that had settled to the sea floor . Chalk is common throughout Western Europe , where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel . Chalk is mined for use in industry, such as for quicklime , bricks and builder's putty , and in agriculture , for raising pH in soils with high acidity . It
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1216-436: The small particles of chalk make it a substance ideal for cleaning and polishing. For example, toothpaste commonly contains small amounts of chalk, which serves as a mild abrasive . Polishing chalk is chalk prepared with a carefully controlled grain size, for very fine polishing of metals. French chalk (also known as tailor's chalk) is traditionally a hard chalk used to make temporary markings on cloth, mainly by tailors . It
1254-428: The tower itself was modernised: two keepers' cottages were built alongside and the interior of the tower (which had previously contained rooms on several storeys) was completely gutted. An inner circular brick wall was then constructed, which supported a new cantilevered stone staircase leading from ground level to the service room, immediately below the lantern. Most of the exterior windows were blocked at this time, and
1292-593: Was Walney Light , automated in 2003. The lighthouse remains operational and is monitored and controlled by Trinity House from its Planning Centre at Harwich . The 1860 optic is still in use with a modern light source displaying a group-flashing characteristic. A painting of the lighthouse by Elwin Hawthorne is in the Russell-Cotes Art Gallery & Museum in Bournemouth . Currently,
1330-452: Was 'GNF'. The transmitting function was later moved about a mile inland, although the medium wave receiving aerial remained operational until closure in 1991. 51°22′29″N 1°26′42″E / 51.37472°N 1.44500°E / 51.37472; 1.44500 Chalk Chalk is a soft, white, porous , sedimentary carbonate rock . It is a form of limestone composed of the mineral calcite and originally formed deep under
1368-461: Was an iron grate quite open to the air in which a good fire of coals was kept blazing at night. In 1719 ownership of both the North and South Foreland lights passed by will to the Trustees of Greenwich Hospital . About the year 1732 the top of this lighthouse was covered with a sort of lantern with large sash windows, and the fire was kept bright by bellows with which the attendants blew throughout
1406-464: Was first lit on 26 March 1860. Three months later a red sector was added to the light, which shone northwards 'to enable vessels at night to keep to the eastward of Margate Sand'. (These works coincided with the successful experiments carried out in 1857–60 at the South Foreland lighthouse by Professor Frederick Hale Holmes with an alternating current electric arc light). At the same time
1444-439: Was named North Foreland after this landmark. 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
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