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Cave Diving Group
The Cave Diving Group (CDG) is a United Kingdom-based diver training organisation specialising in cave diving. The CDG was founded in 1946 by Graham Balcombe, making it the world's oldest continuing diving club. Graham Balcombe and Jack Sheppard pioneered cave diving in the late 1930s, notably at Wookey Hole in Somerset. Passages through caves are often blocked by a submerged section, or sump. Cavers in many countries have tried to pass these barriers in a variety of ways; using the simple "free dive" with a lungful of air or by utilising the available diving technology of the day. Early history of cave diving in the UK Two Post Office engineers, (Francis) Graham Balcombe and (John Arthur) "Jack" Sheppard, who were among the leading climbers and cavers of their era, combined their energies into solving the problem of passing the Swildon's sump. Their pioneering dive on 17 February 1934 used a home-made respirator, designed by Balcombe, that incorporated part of a ladi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cave Diving Group Logo
A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called ''exogene'' caves. Caves which extend further underground than the opening is wide are called ''endogene'' caves. Speleology is the science of exploration and study of all aspects of caves and the cave environment. Visiting or exploring caves for recreation may be called ''caving'', ''potholing'', or ''spelunking''. Formation types The formation and development of caves is known as ''speleogenesis''; it can occur over the course of millions of years. Caves can range widely in size, and are formed by various geological processes. These may involve a combination of chemical processes, erosion by water, tectonic forces, microorganism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penelope Powell
Penelope ( ; Ancient Greek: Πηνελόπεια, ''Pēnelópeia'', or el, Πηνελόπη, ''Pēnelópē'') is a character in Homer's ''Odyssey.'' She was the queen of Ithaca and was the daughter of Spartan king Icarius and naiad Periboea. Penelope is known for her fidelity to her husband Odysseus, despite the attention of more than a hundred suitors during his absence. In one source, Penelope's original name was Arnacia or Arnaea. Etymology Glossed by Hesychius as "some kind of bird" (today arbitrarily identified with the Eurasian wigeon, to which Linnaeus gave the binomial ''Anas penelope''), where () is a common Pre-Greek suffix for predatory animals; however, the semantic relation between the proper name and the gloss is not clear. In folk etymology, () is usually understood to combine the Greek word (), "weft", and (), "face", which is considered the most appropriate for a cunning weaver whose motivation is hard to decipher. Robert S. P. Beekes believed the name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqua-lung
Aqua-Lung was the first open-circuit, self-contained underwater breathing apparatus (or "scuba") to achieve worldwide popularity and commercial success. This class of equipment is now commonly referred to as a twin-hose diving regulator, or demand valve. The Aqua-Lung was invented in France during the winter of 1942–1943 by two Frenchmen: the engineer Émile Gagnan and the Naval Lieutenant (French: "lieutenant de vaisseau") Jacques Cousteau. It allowed Cousteau and Gagnan to film and explore underwater more easily. The invention revolutionised autonomous underwater diving by providing a compact, reliable system capable of a greater depth range and endurance than its precursors, and was a major factor influencing the development of recreational scuba diving after WWII. The twin-hose Aqua-Lung demand regulator is the foundation of all modern scuba regulators. A diaphragm is used to control a valve to deliver the breathing gas to the diver on demand, at ambient water pressure. Ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeological
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscapes. Archaeology can be considered both a social science and a branch of the humanities. It is usually considered an independent academic discipline, but may also be classified as part of anthropology (in North America – the four-field approach), history or geography. Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades. Archaeology is distinct from palaeontology, which is the study of fossil remains. Archaeology is particularly important for learning about prehistoric societies, for which, by definition, there are no written records. Prehistory includes over 99% of the human past, from the Paleolithic until the adven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Wales
South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards to include Carmarthenshire and Pembrokeshire. In the western extent, from Swansea westwards, local people would probably recognise that they lived in both south Wales and west Wales. The Brecon Beacons National Park covers about a third of south Wales, containing Pen y Fan, the highest British mountain south of Cadair Idris in Snowdonia. A point of some discussion is whether the first element of the name should be capitalised: 'south Wales' or 'South Wales'. As the name is a geographical expression rather than a specific area with well-defined borders, style guides such as those of the BBC and ''The Guardian'' use the form 'south Wales'. In a more authoritative style guide, the Welsh Government, in their international gateway website, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebreather
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's breathing, exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from open-circuit breathing apparatus, where the exhaled gas is discharged directly into the environment. The purpose is to extend the breathing endurance of a limited gas supply, and, for covert military use by frogmen or observation of underwater life, eliminating the bubbles produced by an open circuit system and in turn not scaring wildlife being filmed. A rebreather is generally understood to be a portable unit carried by the user. The same technology on a vehicle or non-mobile installation is more likely to be referred to as a life-support system. Rebreather technology may be used where breathing gas supply is limited, such as underwater or in space, where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alum Pot System
An alum () is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula , where is a monovalent cation such as potassium or ammonium. By itself, "alum" often refers to potassium alum, with the formula . Other alums are named after the monovalent ion, such as sodium alum and ammonium alum. The name "alum" is also used, more generally, for salts with the same formula and structure, except that aluminium is replaced by another trivalent metal ion like chromium, and/or sulfur is replaced by another chalcogen like selenium. The most common of these analogs is chrome alum . In most industries, the name "alum" (or "papermaker's alum") is used to refer to aluminium sulfate, , which is used for most industrial flocculation (the variable is an integer whose size depends on the amount of water absorbed into the alum). In medicine, "alum" may also refer to aluminium hydroxide gel used as a vaccine adjuvant. History Alum found at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nidderdale Caves
The Nidderdale Caves are a series of caves in Upper Nidderdale in North Yorkshire, England. There are two cave systems and most of the caves are in some way linked with one or the other. The smaller system is the Eglin cave system in the valley of How Stean Beck, a tributary of the River Nidd, associated with How Stean Gorge. The larger system is the Goyden cave system under the valley of the River Nidd, which flows east from Scar House Reservoir, then south, and shortly after disappears underground down several sink holes to reappear at the rising just beyond the village of Lofthouse. Cavers are able to access several sections of this system via the different entrances. The caves are a Site of Special Scientific Interest designated in 1987 under the name Upper Nidderdale. Entrances From north to south: Manchester Hole(NGR SE 100736 Length 578m) Bax pot(alternative entrance to Manchester Hole Divers chamber, providing through trip) Lesser Stream pot(entrance into connecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keld Head
Keld may refer to: * Keld, Cumbria, England *Keld, North Yorkshire, England *Variation of Kjell (name), a Danish given name * KELD (AM), a radio station (1400 AM) licensed to El Dorado, Arkansas, United States * KELD-FM KELD-FM (106.5 MHz) is a radio station licensed to Hampton, Arkansas Hampton is a town in Calhoun County, Arkansas, United States. The population was 1,324 at the 2010 census. The town is the county seat of Calhoun County. Hampton is part o ..., a radio station (106.5 FM) licensed to Hampton, Arkansas, United States * the ICAO code for South Arkansas Regional Airport at Goodwin Field {{disambiguation, geo, callsign, airport ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three Counties System
The Three Counties System is a set of inter-connected limestone solutional cave systems spanning the borders of Cumbria, Lancashire and North Yorkshire in the north of England. The possibility of connecting a number of discrete cave systems in the area to create a single super-system that spans the county borders was first proposed by Dave Brook in 1968, and it was achieved in 2011. The system is currently over long, making it the longest in the UK and the thirtieth longest in the world, and there continues to be scope for considerably extending the system. Description The Three Counties System's most southerly entrance is currently Large Pot (, NGR SD 6281 7685) on the northerly flank of Kingsdale in North Yorkshire, and the most northerly entrance is currently Bull Pot of the Witches (, NGR SD 6623 8131) beneath Barbon Low Fell in Cumbria – a distance of almost . Between the two, the system passes beneath Ireby Fell and Leck Fell which are in Lancashire. The system runs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yorkshire Dales
The Yorkshire Dales is an upland area of the Pennines in the Historic counties of England, historic county of Yorkshire, England, most of it in the Yorkshire Dales National Park created in 1954. The Dales comprise river valleys and the hills rising from the Vale of York westwards to the hilltops of the Pennine Drainage divide, watershed. In Ribblesdale, Dentdale and Garsdale, the area extends westwards across the watershed, but most of the valleys drain eastwards to the Vale of York, into the River Ouse, Yorkshire, Ouse and the Humber. The extensive limestone cave systems are a major area for caving in the UK and numerous walking trails run through the hills and dales. Etymology The word ''Dale (landform), dale'', like ''dell'', is derived from the Old English word ''dæl''. It has cognates in the North Germanic languages, Nordic/Germanic languages, Germanic words for valley (''dal'', ''tal''), and occurs in valley names across Yorkshire and Northern England. Usage here may have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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