|
Caves Of The Mendip Hills
The caves of the Mendip Hills are formed by the particular geology of the Mendip Hills: large areas of limestone worn away by water makes it a national centre for caving. The hills conceal the largest underground river system in Britain. Geology The hills consist of anticlines of Carboniferous Limestone lying over Devonian Old Red Sandstone, with the sandstone exposed on the summits. When a surface stream running off the sandstone reaches the limestone it sinks below ground through a " swallet", (also known locally as a "slocker"), continuing on its way down towards sea level by enlarging existing cracks in the rock to form caves, and reappearing at the base of the limestone outcrop. As the water changes route within the hill some caves (or parts of caves) are left dry. There is a characteristic type of Mendip cave, in which there is an initially steep descent, and then a more level stretch ending in a "sump" as the cave reaches and descends below the prevailing water table. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is dominated by a maritime climate with narrow temperature differences between seasons. The 60% smaller island of Ireland is to the west—these islands, along with over 1,000 smaller surrounding islands and named substantial rocks, form the British Isles archipelago. Connected to mainland Europe until 9,000 years ago by a landbridge now known as Doggerland, Great Britain has been inhabited by modern humans for around 30,000 years. In 2011, it had a population of about , making it the world's third-most-populous island after Java in Indonesia and Honshu in Japan. The term "Great Britain" is often used to refer to England, Scotland and Wales, including their component adjoining islands. Great Britain and Northern Ireland now constitute the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheddar Gorge
Cheddar Gorge is a limestone gorge in the Mendip Hills, near the village of Cheddar, Somerset, England. The gorge is the site of the Cheddar show caves, where Britain's oldest complete human skeleton, Cheddar Man, estimated to be 9,000 years old, was found in 1903. Older remains from the Upper Late Palaeolithic era (12,000–13,000 years ago) have been found. The caves, produced by the activity of an underground river, contain stalactites and stalagmites. The gorge is part of a Site of Special Scientific Interest called Cheddar Complex. Cheddar Gorge, including the caves and other attractions, has become a tourist destination. In a 2005 poll of ''Radio Times'' readers, following its appearance on the television programme ''Seven Natural Wonders'' (2005), Cheddar Gorge was named as the second greatest natural wonder in Britain, surpassed only by Dan yr Ogof caves. The gorge attracts about 500,000 visitors per year. Geology Cheddar is a gorge lying on the southern edge of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mendip Cave Registry And Archive
The Mendip Cave Registry and Archive (MCRA) has the object of recording and indexing all available information on caves, mines, rock shelters and other sites of speleological interest primarily in the area of Bristol, Somerset, Bath and Wiltshire in South West England. History The MCRA was formed as the Mendip Cave Registry in January 1956. In 1969 the Registry ceased to function but it was revived in 1994 by Dave Irwin. In 2007 it was decided to expand the Registry to include archive material and the name was amended to Mendip Cave Registry and Archive. Publications * Related There are also some established cave registers for other parts of the United Kingdom. These are: Mendip cave registry(already mentioned) Welsh Cave Registeroperated by the Cambrian Caving Counciestablished in the 1960The Caves of Scotlandpresented in the form of a comprehensive one-page bibliography Southern Ireland Cave Bibliographyoperated by UBSS * The Derbyshire Cave Registry, which doesn't h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbert E
Herbert may refer to: People Individuals * Herbert (musician), a pseudonym of Matthew Herbert Name * Herbert (given name) * Herbert (surname) Places Antarctica * Herbert Mountains, Coats Land * Herbert Sound, Graham Land Australia * Herbert, Northern Territory, a rural locality * Herbert, South Australia. former government town * Division of Herbert, an electoral district in Queensland * Herbert River, a river in Queensland * County of Herbert, a cadastral unit in South Australia Canada * Herbert, Saskatchewan, Canada, a town * Herbert Road, St. Albert, Canada New Zealand * Herbert, New Zealand, a town * Mount Herbert (New Zealand) United States * Herbert, Illinois, an unincorporated community * Herbert, Michigan, a former settlement * Herbert Creek, a stream in South Dakota * Herbert Island, Alaska Arts, entertainment, and media Fictional entities * Herbert (Disney character) * Herbert Pocket (''Great Expectations'' character), Pip's close friend and roommate in the Cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and produces a loud noise regardless of confinement. It is widely used in theatrical pyrotechnics and fireworks (namely salutes, e.g., cherry bombs, M-80s, firecrackers, and cap gun shots) and was once used for flashes in photography. Different varieties of flash powder are made from different compositions; most common are potassium perchlorate and aluminium powder. Sometimes, sulfur is included in the mixture to increase the sensitivity. Early formulations used potassium chlorate instead of potassium perchlorate. Flash powder compositions are also used in military pyrotechnics when production of large amount of noise, light, or infrared radiation is required, e.g., missile decoy flares and stun grenades. History Lycopodium powder is a yellow-tan dust-like powder historically used as a flash powder. Today, the principal use of the powder is to create flashes or flames t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Plate
Photographic plates preceded photographic film as a capture medium in photography, and were still used in some communities up until the late 20th century. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinner than common window glass. History Glass plates were far superior to film for research-quality imaging because they were stable and less likely to bend or distort, especially in large-format frames for wide-field imaging. Early plates used the wet collodion process. The wet plate process was replaced late in the 19th century by gelatin dry plates. A view camera nicknamed "The Mammoth" weighing was built by George R. Lawrence in 1899, specifically to photograph "The Alton Limited" train owned by the Chicago & Alton Railway. It took photographs on glass plates measuring × . Glass plate photographic material largely faded from the consumer market in the early years of the 20th century, as more convenient and less fragile fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Camera
A view camera is a large-format camera in which the lens forms an inverted image on a ground-glass screen directly at the film plane. The image is viewed and then the glass screen is replaced with the film, and thus the film is exposed to exactly the same image as was seen on the screen. This type of camera was first developed in the era of the daguerreotypeStroebel, L. D. (1986). ''View Camera Technique'', 5th ed., p. 212. Boston: Focal Press. (1840s–1850s) and is still in use today, some with various drive mechanisms for movements (rather than loosen-move-tighten), more scale markings, and/or more spirit levels. It comprises a flexible bellows that forms a light-tight seal between two adjustable ''standards'', one of which holds a lens, and the other a ground glass or a photographic film holder or a digital back.Stroebel (1986). p. 2. There are three general types, the rail camera, the field camera, and others that don't fit into either category. The bellows is a flexi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ochre
Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced by this pigment, especially a light brownish-yellow. A variant of ochre containing a large amount of hematite, or dehydrated iron oxide, has a reddish tint known as "red ochre" (or, in some dialects, ruddle). The word ochre also describes clays coloured with iron oxide derived during the extraction of tin and copper. Earth pigments Ochre is a family of earth pigments, which includes yellow ochre, red ochre, purple ochre, sienna, and umber. The major ingredient of all the ochres is iron(III) oxide-hydroxide, known as limonite, which gives them a yellow colour. * Yellow ochre, , is a hydrated iron hydroxide (limonite) also called gold ochre. * Red ochre, , takes its reddish colour from the mineral hematite, which is an anhydrous iron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Age
The Iron Age is the final epoch of the three-age division of the prehistory and protohistory of humanity. It was preceded by the Stone Age (Paleolithic, Mesolithic, Neolithic) and the Bronze Age (Chalcolithic). The concept has been mostly applied to Iron Age Europe and the Ancient Near East, but also, by analogy, to other parts of the Old World. The duration of the Iron Age varies depending on the region under consideration. It is defined by archaeological convention. The "Iron Age" begins locally when the production of iron or steel has advanced to the point where iron tools and weapons replace their bronze equivalents in common use. In the Ancient Near East, this transition took place in the wake of the Bronze Age collapse, in the 12th century BC. The technology soon spread throughout the Mediterranean Basin region and to South Asia (Iron Age in India) between the 12th and 11th century BC. Its further spread to Central Asia, Eastern Europe, and Central Europe is somewhat dela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronze Age
The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second principal period of the three-age system proposed in 1836 by Christian Jürgensen Thomsen for classifying and studying ancient societies and history. An ancient civilization is deemed to be part of the Bronze Age because it either produced bronze by smelting its own copper and alloying it with tin, arsenic, or other metals, or traded other items for bronze from production areas elsewhere. Bronze is harder and more durable than the other metals available at the time, allowing Bronze Age civilizations to gain a technological advantage. While terrestrial iron is naturally abundant, the higher temperature required for smelting, , in addition to the greater difficulty of working with the metal, placed it out of reach of common use until the end o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts of the world. This "Neolithic package" included the introduction of farming, domestication of animals, and change from a hunter-gatherer lifestyle to one of settlement. It began about 12,000 years ago when farming appeared in the Epipalaeolithic Near East, and later in other parts of the world. The Neolithic lasted in the Near East until the transitional period of the Chalcolithic (Copper Age) from about 6,500 years ago (4500 BC), marked by the development of metallurgy, leading up to the Bronze Age and Iron Age. In other places the Neolithic followed the Mesolithic (Middle Stone Age) and then lasted until later. In Ancient Egypt, the Neolithic lasted until the Protodynastic period, 3150 BC.Karin Sowada and Peter Grave. Egypt in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
