Channel 4 is a British public-service free-to-air television network that began transmission on 2 November 1982. Although commercially-self-funded, it is publicly-owned. With the conversion of the Wenvoe transmitter group in Wales to digital terrestrial broadcasting on 31 March 2010, Channel 4 became a UK-wide TV channel for the first time; the channel was established to provide a fourth television service to the United Kingdom in addition to the licence-funded BBC One and BBC Two, the single commercial broadcasting network ITV. Before Channel 4 and S4C, Britain had three terrestrial television services: BBC1, BBC2, ITV; the Broadcasting Act 1980 began the process of adding a fourth, Channel 4, along with its Welsh counterpart, was formally created by an Act of Parliament in 1982. After some months of test broadcasts, it began scheduled transmissions on 2 November 1982; the notion of a second commercial broadcaster in the United Kingdom had been around since the inception of ITV in 1954 and its subsequent launch in 1955.
Indeed, television sets sold throughout the 1970s and early 1980s had a spare tuning button labelled "ITV/IBA 2". Throughout ITV's history and until Channel 4 became a reality, a perennial dialogue existed between the GPO, the government, the ITV companies and other interested parties, concerning the form such an expansion of commercial broadcasting would take, it was most politics which had the biggest impact in leading to a delay of three decades before the second commercial channel became a reality. One clear benefit of the "late arrival" of the channel was that its frequency allocations at each transmitter had been arranged in the early 1960s, when the launch of an ITV2 was anticipated; this led to good coverage across most of the country and few problems of interference with other UK-based transmissions. At the time the fourth service was being considered, a movement in Wales lobbied for the creation of dedicated service that would air Welsh-language programmes only catered for at "off peak" times on BBC Wales and HTV.
The campaign was taken so by Gwynfor Evans, former president of Plaid Cymru, that he threatened the government with a hunger strike were it not to honour the plans. The result was that Channel 4 as seen by the rest of the United Kingdom would be replaced in Wales by Sianel Pedwar Cymru. Operated by a specially created authority, S4C would air programmes in Welsh made by HTV, the BBC and independent companies. Limited frequency space meant that Channel 4 could not be broadcast alongside S4C, though some Channel 4 programmes would be aired at less popular times on the Welsh variant, a practice that carried on up until the closure of S4C's analogue transmissions in 2010 when S4C became a Welsh channel. Since carriage on digital cable and digital terrestrial has introduced Channel 4 to Welsh homes where it is now universally available; the first voice heard on Channel 4's opening day of Tuesday 2 November 1982 was that of continuity announcer Paul Coia who said: Good afternoon. It's a pleasure to be able to say to you, welcome to Channel Four.
Following the announcement, the channel headed into a montage of clips from its programmes set to the station's signature tune, "Fourscore", written by David Dundas, which would form the basis of the station's jingles for its first decade. The first programme to air on the channel was the teatime game show Countdown, at 16:45 produced by Yorkshire Television; the first person to be seen on Channel 4 was Richard Whiteley with Ted Moult being the second. The first woman on the channel, contrary to popular belief, was not Whiteley's Countdown co-host Carol Vorderman but a lexicographer only identified as Mary. Whiteley opened the show with the words: As the countdown to a brand new channel ends, a brand new countdown begins. On its first day, Channel 4 broadcast controversial soap opera Brookside, which ran until 2003. On its launch, Channel 4 committed itself to providing an alternative to the existing channels, an agenda in part set out by its remit which required the provision of programming to minority groups.
In step with its remit, the channel became well received both by minority groups and the arts and cultural worlds during this period under founding chief executive Jeremy Isaacs, where the channel gained a reputation for programmes on the contemporary arts. Channel 4 co-commissioned Robert Ashley's ground-breaking television opera Perfect Lives, which it premiered over several episodes in 1984; the channel did not receive mass audiences for much of this period, however, as might be expected for a station focusing on minority interest. Channel 4 began the funding of independent films, such as the Merchant-Ivory docudrama The Courtesans of Bombay, during this time. In 1992, Channel 4 faced its first libel case by Jani Allan, a South African journalist, who objected to her representation in Nick Broomfield's documentary The Leader, His Driver and the Driver's Wife. In September 1993, the channel broadcast the direct-to-TV documentary film Beyond Citizen Kane, in which it displayed the dominant position of the Rede Globo television network, discussed its influence and political connections in Brazil.
After control of the station passed from the Channel Four Television Co
Jonathan B. Sopel is a British television presenter and correspondent for the BBC's international television news channel, BBC World News serving as the North America Editor for the BBC, he was chief political correspondent for the formerly-named domestic news channel BBC News 24, a presenter on the Politics Show on BBC One and the BBC News channel. Born in 1959 to parents Myer and Miriam Sopel, he was educated at Christ's College, Finchley in north London before graduating with a 2:1 honours degree in politics from Southampton University. Sopel was the President of the Students' Union, for the National Organisation of Labour Students during 1982 and 1983. Sopel was a freelance writer and broadcaster before joining the BBC in 1983 as a reporter and producer for BBC Radio Solent, he went on to become the chief political correspondent for BBC News 24 and spent three years as the BBC's Paris correspondent. Stories he covered while he was in Paris included the French ban on the importation of British beef, the millennium celebrations in Paris, the oil spill in Brittany, the French presidency of the EU in 2000 and the Concorde crash in July 2000.
During the 2003 invasion of Iraq, Sopel was the BBC's correspondent in Kuwait City. In 2005, Sopel joined The Politics Show on BBC One replacing Jeremy Vine as the programme's main presenter, it broadcast every Sunday at noon and Sopel interviewed key politicians and advisers, including Prime Minister Tony Blair, opposition leader David Cameron, Jack Straw, Gordon Brown and US Secretary of State Condoleezza Rice. The show ended in December 2011 and was replaced by Sunday Politics in January 2012. Sopel has co-presented the BBC News Channel on weekday afternoons between 2 pm and 5 pm – alongside Louise Minchin each Tuesday to Thursday and alongside Emily Maitlis on Mondays – following his appointment as a presenter on the channel in 2003. During major political stories, such as elections, Sopel reported on location for the BBC News Channel and BBC News at One, he made occasional appearances on BBC One news bulletins as a relief anchor. In his 16 years with the BBC, he has appeared on PM on Radio Four, Breakfast News, BBC News at One, BBC News at Six and BBC News at Ten as well as fronting BBC Two's annual coverage of the UK political party conferences, Conference Live.
He has been an occasional stand-in presenter for Newsnight, has made past appearances on Breakfast, HARDtalk and The Daily Politics. In October 2012, it was announced that Sopel would present the new programme, Global with Jon Sopel, airing 1500 to 1630 GMT every Monday to Thursday on BBC World News. In January 2014, Sopel had a rare interview with the Emir of Dubai, Sheikh Mohammed bin Rashid Al Maktoum. At the end of the following April, Sopel was appointed the BBC's North America Editor, after his predecessor Mark Mardell became a presenter for BBC Radio 4; the 2007 edition of Who's Who listed Sopel's hobbies as golf and watching football. He is an ambassador for The Prince's Trust, he met his wife Linda Twissell while working at Radio Solent. On 20 October 2010, Sopel broke his hip when he crashed his motor scooter on fallen leaves whilst on his way to Westminster to cover BBC's announcement of government spending cuts, he failed to realise the full extent of his injury until after he had completed his journey, subsequently required surgery.
In 2007, Sopel was voted Political Journalist of the Year by the Public Affairs Industry. Sopel was awarded an Honorary Doctorate of Letters by the University of Southampton in 2011. In 2013, Sopel was shortlisted for National Presenter of the Year at the Royal Television Society Television Journalism Awards 2011/2012. Tony Blair: The Moderniser Michael Joseph, London. ISBN 0-7181-3918-6 / 0-7181-3918-6 If Only They Didn't Speak English: notes from Trump's America BBC Books, London ISBN 978-1785942266 Jon Sopel on IMDb
Inorganic chemistry deals with the synthesis and behavior of inorganic and organometallic compounds. This field covers all chemical compounds except the myriad organic compounds, which are the subjects of organic chemistry; the distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the chemical industry, including catalysis, materials science, surfactants, medications and agriculture. Many inorganic compounds are ionic compounds, consisting of cations and anions joined by ionic bonding. Examples of salts are magnesium chloride MgCl2, which consists of magnesium cations Mg2+ and chloride anions Cl−. In any salt, the proportions of the ions are such that the electric charges cancel out, so that the bulk compound is electrically neutral; the ions are described by their oxidation state and their ease of formation can be inferred from the ionization potential or from the electron affinity of the parent elements.
Important classes of inorganic compounds are the oxides, the carbonates, the sulfates, the halides. Many inorganic compounds are characterized by high melting points. Inorganic salts are poor conductors in the solid state. Other important features include their high melting ease of crystallization. Where some salts are soluble in water, others are not; the simplest inorganic reaction is double displacement when in mixing of two salts the ions are swapped without a change in oxidation state. In redox reactions one reactant, the oxidant, lowers its oxidation state and another reactant, the reductant, has its oxidation state increased; the net result is an exchange of electrons. Electron exchange can occur indirectly as well, e.g. in batteries, a key concept in electrochemistry. When one reactant contains hydrogen atoms, a reaction can take place by exchanging protons in acid-base chemistry. In a more general definition, any chemical species capable of binding to electron pairs is called a Lewis acid.
As a refinement of acid-base interactions, the HSAB theory takes into account polarizability and size of ions. Inorganic compounds are found in nature as minerals. Soil may contain iron sulfide as calcium sulfate as gypsum. Inorganic compounds are found multitasking as biomolecules: as electrolytes, in energy storage or in construction; the first important man-made inorganic compound was ammonium nitrate for soil fertilization through the Haber process. Inorganic compounds are synthesized for use as catalysts such as vanadium oxide and titanium chloride, or as reagents in organic chemistry such as lithium aluminium hydride. Subdivisions of inorganic chemistry are organometallic chemistry, cluster chemistry and bioinorganic chemistry; these fields are active areas of research in inorganic chemistry, aimed toward new catalysts and therapies. Inorganic chemistry is a practical area of science. Traditionally, the scale of a nation's economy could be evaluated by their productivity of sulfuric acid.
The top 20 inorganic chemicals manufactured in Canada, Europe, India and the US:Aluminium sulfate, Ammonium nitrate, Ammonium sulfate, Carbon black, hydrochloric acid, hydrogen peroxide, nitric acid, oxygen, phosphoric acid, sodium carbonate, sodium chlorate, sodium hydroxide, sodium silicate, sodium sulfate, sulfuric acid, titanium dioxide. The manufacturing of fertilizers is another practical application of industrial inorganic chemistry. Descriptive inorganic chemistry focuses on the classification of compounds based on their properties; the classification focuses on the position in the periodic table of the heaviest element in the compound by grouping compounds by their structural similarities. When studying inorganic compounds, one encounters parts of the different classes of inorganic chemistry. Different classifications are: Classical coordination compounds feature metals bound to "lone pairs" of electrons residing on the main group atoms of ligands such as H2O, NH3, Cl−, CN−. In modern coordination compounds all organic and inorganic compounds can be used as ligands.
The "metal" is a metal from the groups 3-13, as well as the trans-lanthanides and trans-actinides, but from a certain perspective, all chemical compounds can be described as coordination complexes. The stereochemistry of coordination complexes can be quite rich, as hinted at by Werner's separation of two enantiomers of 6+, an early demonstration that chirality is not inherent to organic compounds. A topical theme within this specialization is supramolecular coordination chemistry. Examples: −, 3+, TiCl42; these species feature elements from groups II, III, IV, V, VI, VII, 0 of the periodic table. Due to their similar reactivity, the elements in group 3 and group 12 are generally included, the lanthanides and actinides are sometimes included as well. Main group compounds have been known since the beginnings of chemistry, e.g. elemental sulfur and the distillable white phosphorus. Experiments on oxygen, O2, by Lavoisier and Priestley not only iden
Standard Chinese known as Modern Standard Mandarin, Standard Mandarin, Modern Standard Mandarin Chinese, or Mandarin, is a standard variety of Chinese, the sole official language of China, the de facto official language of Taiwan and one of the four official languages of Singapore. Its pronunciation is based on the Beijing dialect, its vocabulary on the Mandarin dialects, its grammar is based on written vernacular Chinese. Like other varieties of Chinese, Standard Chinese is a tonal language with topic-prominent organization and subject–verb–object word order, it has more initial consonants but final consonants and tones than southern varieties. Standard Chinese is an analytic language, though with many compound words. There are two standardised forms of the language, namely Putonghua in Mainland China and Guoyu in Taiwan. Aside from a number of differences in pronunciation and vocabulary, Putonghua is written using simplified Chinese characters, Guoyu is written using traditional Chinese characters.
Many characters are identical between the two systems. In Chinese, the standard variety is known as: 普通话 in the People's Republic of China, as well as Hong Kong and Macau. Standard Chinese is commonly referred to by generic names for "Chinese", notably 中文. In total, there have been known over 20 various names for the language; the term Guoyu had been used by non-Han rulers of China to refer to their languages, but in 1909 the Qing education ministry applied it to Mandarin, a lingua franca based on northern Chinese varieties, proclaiming it as the new "national language". The name Putonghua has a long, albeit unofficial, history, it was used as early as 1906 in writings by Zhu Wenxiong to differentiate a modern, standard Chinese from classical Chinese and other varieties of Chinese. For some linguists of the early 20th century, the Putonghua, or "common tongue/speech", was conceptually different from the Guoyu, or "national language"; the former was a national prestige variety. Based on common understandings of the time, the two were, in fact, different.
Guoyu was understood as formal vernacular Chinese, close to classical Chinese. By contrast, Putonghua was called "the common speech of the modern man", the spoken language adopted as a national lingua franca by conventional usage; the use of the term Putonghua by left-leaning intellectuals such as Qu Qiubai and Lu Xun influenced the People's Republic of China government to adopt that term to describe Mandarin in 1956. Prior to this, the government used both terms interchangeably. In Taiwan, Guoyu continues to be the official term for Standard Chinese; the term Guoyu however, is less used in the PRC, because declaring a Beijing dialect-based standard to be the national language would be deemed unfair to speakers of other varieties and to the ethnic minorities. The term Putonghua, on the contrary, implies nothing more than the notion of a lingua franca. During the government of a pro-Taiwan independence coalition, Taiwan officials promoted a different reading of Guoyu as all of the "national languages", meaning Hokkien and Formosan as well as Standard Chinese.
Huayu, or "language of the Chinese nation" simply meant "Chinese language", was used in overseas communities to contrast Chinese with foreign languages. Over time, the desire to standardise the variety of Chinese spoken in these communities led to the adoption of the name "Huayu" to refer to Mandarin; this name avoids choosing a side between the alternative names of Putonghua and Guoyu, which came to have political significance after their usages diverged along political lines between the PRC and the ROC. It incorporates the notion that Mandarin is not the national or common language of the areas in which overseas Chinese live. Hanyu, or "language of the Han people", is another umbrella term used for Chinese. However, it has confusingly two different meanings: Standard Chinese; this term, as well as Hànzú, is a modern concept. A related concept is Hànzì; the term "Mandarin" is a translation of Guānhuà, which referred to the lingua franca of the late Chinese empire. The Chinese term is obsolete as a name for the standard language, but is used by linguists to refer to the major group of Mandarin dialects spoken natively across most of northern and southwestern China.
In English, "Mandarin" may refer to the standard language, the dialect group as a whole, or to historic forms such as the late Imperial lingua franca. The name "Modern Standard Mandarin" is sometimes used by linguists who wish to distinguish the current state of the shared language from other northern and historic dialects; the Chinese have different languages in different provinces, to such an extent
Jon Snow (journalist)
Jonathan George Snow HonFRIBA is an English journalist and television presenter. He is best known as the longest-running presenter of Channel 4 News, which he has presented since 1989. Although Channel 4's news programming is produced by ITN, Snow is employed directly by the broadcaster. Snow has held numerous honorary appointments, including Chancellor of Oxford Brookes University from 2001 to 2008. Snow was born in Ardingly, the son of George D'Oyly Snow, Bishop of Whitby, Joan, a pianist who studied at the Royal College of Music, he is a grandson of First World War General Sir Thomas D'Oyly Snow and is the cousin of retired BBC television news presenter Peter Snow. Snow spent five years at the Pilgrims' School, he grew up at Ardingly College. In 2013, he recounted how the inquiry into Sir Jimmy Savile had allowed him to re-evaluate his own childhood when he was molested by one of the school's domestic staff. Snow subsequently attended St Edward's School in Oxford; when he was 18, he spent a year as a VSO volunteer teaching in Uganda.
After mixed success in his first attempt to pass his A-level qualifications, he moved to the Yorkshire Coast College, where he obtained the necessary qualifications to gain a place reading Law at the University of Liverpool. However, he did not complete his undergraduate studies, being expelled for his part in a 1970 anti-apartheid socialist student protest, which he described as "an absolute watershed in my life". After leaving Liverpool, Snow was hired by Lord Longford to direct the New Horizon Youth Centre, a day centre for homeless young people in central London, an organisation with which he has remained involved and of which he subsequently became chairman. By 1978 he was working as a correspondent for ITN, in November of that year was sent on a mission to Vietnam to report on the plight of the boat people, he served as ITN's Washington correspondent and as diplomatic editor before becoming the main presenter of Channel 4 News in 1989. In 1992 he was the main anchor for ITN's election night programme, broadcast on ITV.
He has won several RTS Awards – two for reports from El Salvador, one for his reporting of the Kegworth air disaster as well as the 1995 Award for Best Male Presenter and the 1980 Award for TV Journalist of the Year for his coverage of Afghanistan and the Middle East. Snow is known for sporting his vast collection of colourful socks. While working as a journalist in Uganda, he flew alongside President Idi Amin in the presidential jet, he has recounted how whilst Amin appeared to be asleep he thought about taking Amin's revolver and shooting him dead, but was worried about the consequences of firing a loose round in a jet. In 1976, Snow rejected an approach by British intelligence services to spy on his colleagues. At first he was asked to supply information about the Communist Party, but he was asked to spy on certain "left-wing people" working in television. In return he would have received secret monthly, tax-free payments into his bank account, matching his salary. In 2002 he returned to radio, presenting Jon Snow Reports on Oneword Radio, a weekly show and podcast.
He wrote regular articles for the Channel 4 News website and Snowmail – a daily email newsletter on the big stories coming up on the evening edition of Channel 4 News. In 2003, at the height of the dodgy dossier affair, Alastair Campbell walked into the studio to rebut statements by the BBC. Without notes or preparation, Snow attempted to question Campbell about the affair. In 2004, Snow published an Shooting History; the book was published by Harper Perennial and detailed Snow's life from his childhood up to the 2003 invasion of Iraq. Snow refuses to wear any symbol. On 28 February 2008, Snow said that the silence of the British media on the decision to allow Prince Harry to fight in Afghanistan was unacceptable: "I never thought I'd find myself saying thank God for Drudge; the infamous US blogger has broken the best kept editorial secret of recent times. Editors have been sworn to secrecy over Prince Harry being sent to fight in Afghanistan three months ago." These remarks provoked criticism from some media outlets.
On 9 February 2009, Snow interviewed Lt-Col Yvonne Bradley, the military counsel for Binyam Mohamed, a British resident detained for five years at Guantánamo Bay. Snow asked. Mohamed was released and returned to Britain on 23 February 2009. In November 2010 Snow was sent to Haiti to report on the cholera outbreak. On 14 June 2011, Snow presented the multiple award-winning investigation documentary Sri Lanka's Killing Fields, directed by Callum Macrae, which documented war crimes committed in the final days of the Sri Lankan conflict in 2009; the programme consisted of some of the most horrific footage broadcast in the UK. In early 2014, Snow had a debate with comedian and ac
BBC Two is the second flagship television channel of the British Broadcasting Corporation in the United Kingdom, Isle of Man and Channel Islands. It covers a wide range of subject matter, but tends to broadcast more "highbrow" programmes than the more mainstream and popular BBC One. Like the BBC's other domestic TV and radio channels, it is funded by the television licence, is therefore free of commercial advertising, it is a comparatively well-funded public-service network attaining a much higher audience share than most public-service networks worldwide. Styled BBC2, it was the third British television station to be launched, from 1 July 1967, Europe's first television channel to broadcast in colour, it was envisaged as a home for less mainstream and more ambitious programming, while this tendency has continued to date, most special-interest programmes of a kind broadcast on BBC Two, for example the BBC Proms, now tend to appear on BBC Four instead. British television at the time of BBC2's launch consisted of two channels: the BBC Television Service and the ITV network made up of smaller regional companies.
Both channels had existed in a state of competition since ITV's launch in 1955, both had aimed for a populist approach in response. The 1962 Pilkington Report on the future of broadcasting noticed this, that ITV lacked any serious programming, it therefore decided that Britain's third television station should be awarded to the BBC. Prior to its launch, the new BBC2 was promoted on the BBC Television Service: the soon to be renamed BBC1; the animated adverts featured the campaign mascots "Hullabaloo", a mother kangaroo, "Custard", her joey. Prior to, several years after, the channel's formal launch, the channel broadcast "Trade Test Transmissions", short films made externally by companies such as Shell and BP, which served to enable engineers to test reception, but became cult viewing; the channel was scheduled to begin at 19:20 on 20 April 1964, showing an evening of light entertainment, starting with the comedy show The Alberts, a performance from Soviet comedian Arkady Raikin, a production of Cole Porter's Kiss Me, culminating with a fireworks display.
However, at around 18:45 a huge power failure, originating from a fire at Battersea Power Station, caused Television Centre, indeed much of west London, to lose all power. BBC1 was able to continue broadcasting via its facilities at Alexandra Palace, but all attempts to show the scheduled programmes on the new channel failed. Associated-Rediffusion, the London weekday ITV franchise-holder, offered to transmit on the BBC's behalf, but their gesture was rejected. At 22:00 programming was postponed until the following morning; as the BBC's news centre at Alexandra Palace was unaffected, they did in fact broadcast brief bulletins on BBC2 that evening, beginning with an announcement by the newsreader Gerald Priestland at around 19:25. There was believed to be no recording made of this bulletin, but a videotape was discovered in early 2003. By 11:00 on 21 April, power had been restored to the studios and programming began, thus making Play School the first programme to be shown on the channel; the launch schedule, postponed from the night before, was successfully shown that evening, albeit with minor changes.
In reference to the power cut, the transmission opened with a shot of a lit candle, sarcastically blown out by presenter Denis Tuohy. To establish the new channel's identity and draw viewers to it, the BBC decided that a promoted, lavish series would be essential in its earliest days; the production chosen was The Forsyte Saga, a no-expense-spared adaptation of the novels by John Galsworthy, featuring well-established actors Kenneth More and Eric Porter. Critically for the future of the fledgling channel, the BBC's gamble was hugely successful, with an average of six million viewers tuning in per episode: a feat made more prominent by the fact that only 9 million were able to receive the channel at the time. Unlike BBC1 and ITV, BBC2 was broadcast only on the 625 line UHF system, so was not available to viewers still using sets on the 405-line VHF system; this created a market for dual standard receivers. Set manufacturers ramped up production of UHF sets in anticipation of a large market demand for the new BBC2, but the market did not materialise.
The early technical problems, which included being unable to transmit US-recorded videotapes due to a lack of system conversion from the US NTSC system, were resolved by a committee headed by James Redmond. On 1 July 1967, during the Wimbledon Championships, BBC2 became the first channel in Europe to begin regular broadcasts in colour, using the PAL system; the thirteen part series Civilisation was created as a celebration of two millennia of western art and culture to showpiece the new colour technology. BBC1 and ITV joined BBC2 on 625-line UHF band, but continued to simulcast on 405-line VHF until 1985. BBC1 and ITV introduced PAL colour on UHF on 15 November 1969, although they both had broadcast some programmes in colour "unofficially" since September 1969. In 1979, the station adopted the first computer-generated channel identification in Britain, with its use of the double striped, orange'2' logo; the ident, created in house by BBC engineers, lasted until March 1986 and heralded the start of computer-generated logos.
As the switch to digital-only terrestrial transmission progressed, BBC Two was the first analogue TV channel to be replaced with the BBC multiplex, at first four two weeks ahead of the other four channels. This was required for those relay transmitters that had no current Freeview service giving vie
Sheffield is a city and metropolitan borough in South Yorkshire, England. Part of the West Riding of Yorkshire, its name derives from the River Sheaf, which runs through the city. With some of its southern suburbs annexed from Derbyshire, the city has grown from its industrial roots to encompass a wider economic base; the population of the City of Sheffield is 577,800 and it is one of the eight largest regional English cities that make up the Core Cities Group. Sheffield is the third-largest English district by population; the metropolitan population of Sheffield is 1,569,000. The city is in the eastern foothills of the Pennines, the valleys of the River Don and its four tributaries, the Loxley, the Porter Brook, the Rivelin and the Sheaf. Sixty-one per cent of Sheffield's entire area is green space, a third of the city lies within the Peak District national park. There are more than 250 parks and gardens in the city, estimated to contain around 4.5 million trees. Sheffield played a crucial role in the Industrial Revolution, with many significant inventions and technologies developed in the city.
In the 19th century, the city saw a huge expansion of its traditional cutlery trade, when stainless steel and crucible steel were developed locally, fuelling an tenfold increase in the population. Sheffield received its municipal charter in 1843, becoming the City of Sheffield in 1893. International competition in iron and steel caused a decline in these industries in the 1970s and 1980s, coinciding with the collapse of coal mining in the area; the 21st century has seen extensive redevelopment in Sheffield, along with other British cities. Sheffield's gross value added has increased by 60% since 1997, standing at £9.2 billion in 2007. The economy has experienced steady growth averaging around 5% annually, greater than that of the broader region of Yorkshire and the Humber; the city has a long sporting heritage, is home to the world's oldest football club, Sheffield F. C. Games between the two professional clubs, Sheffield United and Sheffield Wednesday, are known as the Steel City derby; the city is home to the World Snooker Championship and the Sheffield Steelers, the UK's first professional ice hockey team.
The area now occupied by the City of Sheffield is believed to have been inhabited since at least the late Upper Paleolithic, about 12,800 years ago. The earliest evidence of human occupation in the Sheffield area was found at Creswell Crags to the east of the city. In the Iron Age the area became the southernmost territory of the Pennine tribe called the Brigantes, it is this tribe who are thought to have constructed several hill forts around Sheffield. Following the departure of the Romans, the Sheffield area may have been the southern part of the Brittonic kingdom of Elmet, with the rivers Sheaf and Don forming part of the boundary between this kingdom and the kingdom of Mercia. Anglian settlers pushed west from the kingdom of Deira. A Britonnic presence within the Sheffield area is evidenced by two settlements called Wales and Waleswood close to Sheffield; the settlements that grew and merged to form Sheffield, date from the second half of the first millennium, are of Anglo-Saxon and Danish origin.
In Anglo-Saxon times, the Sheffield area straddled the border between the kingdoms of Mercia and Northumbria. The Anglo-Saxon Chronicle reports that Eanred of Northumbria submitted to Egbert of Wessex at the hamlet of Dore in 829, a key event in the unification of the kingdom of England under the House of Wessex. After the Norman conquest of England, Sheffield Castle was built to protect the local settlements, a small town developed, the nucleus of the modern city. By 1296, a market had been established at what is now known as Castle Square, Sheffield subsequently grew into a small market town. In the 14th century, Sheffield was noted for the production of knives, as mentioned in Geoffrey Chaucer's The Canterbury Tales, by the early 1600s it had become the main centre of cutlery manufacture in England outside London, overseen by the Company of Cutlers in Hallamshire. From 1570 to 1584, Queen of Scots, was imprisoned in Sheffield Castle and Sheffield Manor. During the 1740s, a form of the crucible steel process was discovered that allowed the manufacture of a better quality of steel than had been possible.
In about the same period, a technique was developed for fusing a thin sheet of silver onto a copper ingot to produce silver plating, which became known as Sheffield plate. These innovations spurred Sheffield's growth as an industrial town, but the loss of some important export markets led to a recession in the late 18th and early 19th century; the resulting poor conditions culminated in a cholera epidemic that killed 402 people in 1832. The population of the town grew throughout the 19th century; the Sheffield and Rotherham railway was constructed in 1838. The town was incorporated as a borough in 1842, was granted a city charter in 1893; the influx of people led to demand for better water supplies, a number of new reservoirs were constructed on the outskirts of the town. The collapse of the dam wall of one of these reservoirs in 1864 resulted in the Great Sheffield Flood, which killed 270 people and devastated large parts of the town; the growing population led to the construction of many back-to-back dwellings that, along with severe pollution from the factories, inspired George Orwell in 1937 to write: "Sheffield, I suppose, could justly claim to be called the ugliest town in the Old World".
The Great Depression hit the city in the 1930s, but as international tensions increased and the Second