London
London is the capital and largest city of both England and the United Kingdom. Standing on the River Thames in the south-east of England, at the head of its 50-mile estuary leading to the North Sea, London has been a major settlement for two millennia. Londinium was founded by the Romans; the City of London, London's ancient core − an area of just 1.12 square miles and colloquially known as the Square Mile − retains boundaries that follow its medieval limits. The City of Westminster is an Inner London borough holding city status. Greater London is governed by the Mayor of the London Assembly. London is considered to be one of the world's most important global cities and has been termed the world's most powerful, most desirable, most influential, most visited, most expensive, sustainable, most investment friendly, most popular for work, the most vegetarian friendly city in the world. London exerts a considerable impact upon the arts, education, fashion, healthcare, professional services and development, tourism and transportation.
London ranks 26 out of 300 major cities for economic performance. It is one of the largest financial centres and has either the fifth or sixth largest metropolitan area GDP, it is the most-visited city as measured by international arrivals and has the busiest city airport system as measured by passenger traffic. It is the leading investment destination, hosting more international retailers and ultra high-net-worth individuals than any other city. London's universities form the largest concentration of higher education institutes in Europe. In 2012, London became the first city to have hosted three modern Summer Olympic Games. London has a diverse range of people and cultures, more than 300 languages are spoken in the region, its estimated mid-2016 municipal population was 8,787,892, the most populous of any city in the European Union and accounting for 13.4% of the UK population. London's urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants at the 2011 census.
The population within the London commuter belt is the most populous in the EU with 14,040,163 inhabitants in 2016. London was the world's most populous city from c. 1831 to 1925. London contains four World Heritage Sites: the Tower of London. Other landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge, Trafalgar Square and The Shard. London has numerous museums, galleries and sporting events; these include the British Museum, National Gallery, Natural History Museum, Tate Modern, British Library and West End theatres. The London Underground is the oldest underground railway network in the world. "London" is an ancient name, attested in the first century AD in the Latinised form Londinium. Over the years, the name has attracted many mythicising explanations; the earliest attested appears in Geoffrey of Monmouth's Historia Regum Britanniae, written around 1136. This had it that the name originated from a supposed King Lud, who had taken over the city and named it Kaerlud.
Modern scientific analyses of the name must account for the origins of the different forms found in early sources Latin, Old English, Welsh, with reference to the known developments over time of sounds in those different languages. It is agreed; this was adapted into Latin as Londinium and borrowed into Old English, the ancestor-language of English. The toponymy of the Common Brythonic form is much debated. A prominent explanation was Richard Coates's 1998 argument that the name derived from pre-Celtic Old European *lowonida, meaning "river too wide to ford". Coates suggested that this was a name given to the part of the River Thames which flows through London. However, most work has accepted a Celtic origin for the name, recent studies have favoured an explanation along the lines of a Celtic derivative of a proto-Indo-European root *lendh-, combined with the Celtic suffix *-injo- or *-onjo-. Peter Schrijver has suggested, on these grounds, that the name meant'place that floods'; until 1889, the name "London" applied to the City of London, but since it has referred to the County of London and Greater London.
"London" is sometimes written informally as "LDN". In 1993, the remains of a Bronze Age bridge were found on the south foreshore, upstream of Vauxhall Bridge; this bridge either reached a now lost island in it. Two of those timbers were radiocarbon dated to between 1750 BC and 1285 BC. In 2010 the foundations of a large timber structure, dated to between 4800 BC and 4500 BC, were found on the Thames's south foreshore, downstream of Vauxhall Bridge; the function of the mesolithic structure is not known. Both structures are on the south bank. Although there is evidence of scattered Brythonic settlements in the area, the first major settlement was founded by the Romans about four years after the invasion
Kingdom of Great Britain
The Kingdom of Great Britain called Great Britain, was a sovereign state in western Europe from 1 May 1707 to 31 December 1800. The state came into being following the Treaty of Union in 1706, ratified by the Acts of Union 1707, which united the kingdoms of England and Scotland to form a single kingdom encompassing the whole island of Great Britain and its outlying islands, with the exception of the Isle of Man and the Channel Islands; the unitary state was governed by a single parliament and government, based in Westminster. The former kingdoms had been in personal union since James VI of Scotland became King of England and King of Ireland in 1603 following the death of Elizabeth I, bringing about the "Union of the Crowns". After the accession of George I to the throne of Great Britain in 1714, the kingdom was in a personal union with the Electorate of Hanover; the early years of the unified kingdom were marked by Jacobite risings which ended in defeat for the Stuart cause at Culloden in 1746.
In 1763, victory in the Seven Years' War led to the dominance of the British Empire, to become the foremost global power for over a century and grew to become the largest empire in history. The Kingdom of Great Britain was replaced by the United Kingdom of Great Britain and Ireland on 1 January 1801 with the Acts of Union 1800; the name Britain descends from the Latin name for the island of Great Britain, Britannia or Brittānia, the land of the Britons via the Old French Bretaigne and Middle English Bretayne, Breteyne. The term Great Britain was first used in 1474; the use of the word "Great" before "Britain" originates in the French language, which uses Bretagne for both Britain and Brittany. French therefore distinguishes between the two by calling Britain la Grande Bretagne, a distinction, transferred into English; the Treaty of Union and the subsequent Acts of Union state that England and Scotland were to be "United into One Kingdom by the Name of Great Britain", as such "Great Britain" was the official name of the state, as well as being used in titles such as "Parliament of Great Britain".
Both the Acts and the Treaty describe the country as "One Kingdom" and a "United Kingdom", which has led some much publications into the error of treating the "United Kingdom" as a name before it came into being in 1801. The websites of the Scottish Parliament, the BBC, others, including the Historical Association, refer to the state created on 1 May 1707 as the United Kingdom of Great Britain; the term United Kingdom was sometimes used during the 18th century to describe the state, but was not its name. The kingdoms of England and Scotland, both in existence from the 9th century, were separate states until 1707. However, they had come into a personal union in 1603, when James VI of Scotland became king of England under the name of James I; this Union of the Crowns under the House of Stuart meant that the whole of the island of Great Britain was now ruled by a single monarch, who by virtue of holding the English crown ruled over the Kingdom of Ireland. Each of the three kingdoms maintained laws.
Various smaller islands were in the king's domain, including the Isle of Man and the Channel Islands. This disposition changed when the Acts of Union 1707 came into force, with a single unified Crown of Great Britain and a single unified parliament. Ireland remained formally separate, with its own parliament, until the Acts of Union 1800; the Union of 1707 provided for a Protestant-only succession to the throne in accordance with the English Act of Settlement of 1701. The Act of Settlement required that the heir to the English throne be a descendant of the Electress Sophia of Hanover and not be a Catholic. Legislative power was vested in the Parliament of Great Britain, which replaced both the Parliament of England and the Parliament of Scotland. In practice it was a continuation of the English parliament, sitting at the same location in Westminster, expanded to include representation from Scotland; as with the former Parliament of England and the modern Parliament of the United Kingdom, the Parliament of Great Britain was formally constituted of three elements: the House of Commons, the House of Lords, the Crown.
The right of the English peerage to sit in the House of Lords remained unchanged, while the disproportionately large Scottish peerage was permitted to send only 16 representative peers, elected from amongst their number for the life of each parliament. The members of the former English House of Commons continued as members of the British House of Commons, but as a reflection of the relative tax bases of the two countries the number of Scottish representatives was reduced to 45. Newly created peers in the Peerage of Great Britain were given the automatic right to sit in the Lords. Despite the end of a separate parliament for Scotland, it retained its own laws and system of courts, As its own established Presbyterian Church, control over its own schools; the social structure was hierarchical, the same elite remain in control after 1707. Scotland continued to have its own excellent universities, with the strong intellectual community in Edinburgh, The Scottish Enlightenment had a major impact on British and European thinking.
As a result of Poynings' Law of 1495, the Parliament of Ireland was subordinate to the Parliament of England, after 1707 to the Parliament of Great Britain. The Westminster parliament's Declaratory Act 1719 (also called the Dependency of Ireland
Thomas Newcomen
Thomas Newcomen was an English inventor who created the atmospheric engine, the first practical fuel-burning engine in 1712. He was an ironmonger by trade and a Baptist lay preacher by calling, he was born in Dartmouth, England, to a merchant family and baptised at St. Saviour's Church on 28 February 1664. In those days flooding in coal and tin mines was a major problem, Newcomen was soon engaged in trying to improve ways to pump out the water from such mines, his ironmonger's business specialised in designing and selling tools for the mining industry. Thomas Newcomen was a teaching elder in the local Baptist church. After 1710 he became the pastor of a local group of Baptists, his father had been one of a group. One of Newcomen's business contacts in London, Edward Wallin, was another Baptist minister who had connections with the well-known Doctor John Gill of Horsleydown, Southwark. Newcomen's connection with the Baptist church at Bromsgrove materially aided the spread of his steam engine, as the engineers Jonathan Hornblower were involved in the same church.
Newcomen's great achievement was his steam engine, developed around 1712. It is that Newcomen was acquainted with Savery, whose forebears were merchants in south Devon. Savery had a post with the Commissioners for Sick and Hurt Seamen, which took him to Dartmouth. Savery had devised a "fire engine", a kind of thermic syphon, in which steam was admitted to an empty container and condensed; the vacuum thus created was used to suck water from the sump at the bottom of the mine. The "fire engine" was not effective and could not work beyond a limited depth of around thirty feet. Newcomen replaced the receiving vessel with a cylinder containing a piston based on Papin's design. Instead of the vacuum drawing in water, it drew down the piston; this was used to work a beam engine. On the other side of the beam was a chain attached to a pump at the base of the mine; as the steam cylinder was refilled with steam, readying it for the next power stroke, water was drawn into the pump cylinder and expelled into a pipe to the surface by the weight of the machinery.
Newcomen and his partner John Calley built the first successful engine of this type at the Conygree Coalworks near Dudley in the West Midlands. A working replica of this engine can be seen at the Black Country Living Museum nearby. Comparatively little is known of Newcomen's life. After 1715 the engine affairs were conducted through an unincorporated company, the'Proprietors of the Invention for Raising Water by Fire', its secretary and treasurer was clerk to the Society of Apothecaries in London. That society formed a company which had a monopoly on supplying medicines to the Navy providing a close link with Savery, whose will he witnessed; the Committee of the Proprietors included Edward Wallin, a Baptist of Swedish descent. Newcomen died at Wallin's house in 1729, was buried at Bunhill Fields burial ground on the outskirts of the City of London: the exact site of his grave is unknown. By 1733 about 125 Newcomen engines, operating under Savery's patent, had been installed by Newcomen and others in most of the important mining districts of Britain and on the Continent of Europe: draining coal mines in the Black Country and near Newcastle upon Tyne.
The Newcomen engine held its place without material change for about 75 years, spreading to more areas of the UK and mainland Europe. At first brass cylinders were used. New iron casting techniques pioneered by the Coalbrookdale Company in the 1720s allowed bigger cylinders to be used, up to about 6 feet in diameter by the 1760s. Experience led to better construction and minor refinements in layout, its mechanical details were much improved by John Smeaton, who built many large engines of this type in the early 1770s. By 1775 about 600 Newcomen engines had been built, although many of these had worn out before and been abandoned or replaced; the Newcomen Engine was by no means an efficient machine, although it was as complicated as engineering and materials techniques of the early 18th century could support. Much heat was lost as this cooled the cylinder; this did not matter unduly at a colliery, where unsaleable small coal was available, but increased the mining costs where coal was not available, as in Cornwall.
Newcomen's engine was replaced after 1775 in areas where coal was expensive by an improved design, invented by James Watt, in which the steam was condensed in a separate condenser. The Watt steam engine, aided by better engineering techniques including Wilkinson's boring machine, was much more fuel efficient, enabling Watt and his partner Matthew Boulton to collect substantial royalties based on the fuel saved. Watt subsequently made other improvements, including the double-acting engine, where both the up and down strokes were power strokes; these were suitable for driving textile mills, many Watt engines were employed in these industries. At first attempts to drive machinery by Newcomen engines had mixed success, as t
Steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder; this pushing force is transformed, into rotational force for work. The term "steam engine" is applied only to reciprocating engines as just described, not to the steam turbine. Steam engines are external combustion engines, where the working fluid is separated from the combustion products; the ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term steam engine can refer to either complete steam plants such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary steam engine. Steam-driven devices were known as early as the aeliopile in the first century AD, with a few other uses recorded in the 16th and 17th century. Thomas Savery's dewatering pump used steam pressure operating directly on water.
The first commercially-successful engine that could transmit continuous power to a machine was developed in 1712 by Thomas Newcomen. James Watt made a critical improvement by removing spent steam to a separate vessel for condensation improving the amount of work obtained per unit of fuel consumed. By the 19th century, stationary steam engines powered the factories of the Industrial Revolution. Steam engines replaced sail for ships, steam locomotives operated on the railways. Reciprocating piston type steam engines were the dominant source of power until the early 20th century, when advances in the design of electric motors and internal combustion engines resulted in the replacement of reciprocating steam engines in commercial usage. Steam turbines replaced reciprocating engines in power generation, due to lower cost, higher operating speed, higher efficiency; the first recorded rudimentary steam-powered "engine" was the aeolipile described by Hero of Alexandria, a mathematician and engineer in Roman Egypt in the first century AD.
In the following centuries, the few steam-powered "engines" known were, like the aeolipile experimental devices used by inventors to demonstrate the properties of steam. A rudimentary steam turbine device was described by Taqi al-Din in Ottoman Egypt in 1551 and by Giovanni Branca in Italy in 1629. Jerónimo de Ayanz y Beaumont received patents in 1606 for 50 steam powered inventions, including a water pump for draining inundated mines. Denis Papin, a Huguenot refugee, did some useful work on the steam digester in 1679, first used a piston to raise weights in 1690; the first commercial steam-powered device was a water pump, developed in 1698 by Thomas Savery. It used condensing steam to create a vacuum which raised water from below and used steam pressure to raise it higher. Small engines were effective, they were prone to boiler explosions. Savery's engine was used in mines, pumping stations and supplying water to water wheels that powered textile machinery. Savery engine was of low cost. Bento de Moura Portugal introduced an improvement of Savery's construction "to render it capable of working itself", as described by John Smeaton in the Philosophical Transactions published in 1751.
It continued to be manufactured until the late 18th century. One engine was still known to be operating in 1820; the first commercially-successful engine that could transmit continuous power to a machine, was the atmospheric engine, invented by Thomas Newcomen around 1712. It improved on Savery's steam pump. Newcomen's engine was inefficient, used for pumping water, it worked by creating a partial vacuum by condensing steam under a piston within a cylinder. It was employed for draining mine workings at depths hitherto impossible, for providing reusable water for driving waterwheels at factories sited away from a suitable "head". Water that passed over the wheel was pumped up into a storage reservoir above the wheel. In 1720 Jacob Leupold described a two-cylinder high-pressure steam engine; the invention was published in his major work "Theatri Machinarum Hydraulicarum". The engine used two heavy pistons to provide motion to a water pump; each piston was returned to its original position by gravity.
The two pistons shared a common four way rotary valve connected directly to a steam boiler. The next major step occurred when James Watt developed an improved version of Newcomen's engine, with a separate condenser. Boulton and Watt's early engines used half as much coal as John Smeaton's improved version of Newcomen's. Newcomen's and Watt's early engines were "atmospheric", they were powered by air pressure pushing a piston into the partial vacuum generated by condensing steam, instead of the pressure of expanding steam. The engine cylinders had to be large because the only usable force acting on them was atmospheric pressure. Watt developed his engine further, modifying it to provide a rotary motion suitable for driving machinery; this enabled factories to be sited away from rivers, accelerated the pace of the Industrial Revolution. The meaning of high pressure, together with an actual value above ambient, depends on the era in which the term was used. For early use of the term Van Reimsdijk refers to steam being at a sufficiently high pressure that it could be exhausted to atmosphere without reliance on a vacuum to enable it to perform useful work.
Ewing states that Watt's condensing engines were known, at the time, as low pressure compared to high pressure, non-condensing engines of the same period. Watt's patent prevented others from making high pres
St Bride's Church
St Bride's Church is a church in the City of London, England. The building's most recent incarnation was designed by Sir Christopher Wren in 1672 in Fleet Street in the City of London, though Wren's original building was gutted by fire during the London Blitz in 1940. Due to its location in Fleet Street, it has a long association with newspapers; the church is a distinctive sight on London's skyline and is visible from a number of locations. Standing 226 feet high, it is the second tallest of all Wren's churches, with only St Paul's itself having a higher pinnacle; this is the church that inspired Cassandra Clare’s London Institute in her Shadowhunter Chronicles novels. St. Bride's may be one of the most ancient churches in London, with worship dating back to the conversion of the Middle Saxons in the 7th century, it has been conjectured that, as the patron saint is Bridget of Ireland, it may have been founded by Celtic monks, missionaries proselytising the English. The present St Bride's is at least the seventh church to have stood on the site.
Traditionally, it was founded by St Bridget in the sixth century. Whether or not she founded it the remnants of the first church appear to have significant similarities to a church of the same date in Kildare, Ireland; the Norman church, built in the 11th century, was of both religious and secular significance. It was replaced by a larger church in the 15th century,St Bride's association with the newspaper business began in 1500, when Wynkyn de Worde set up a printing press next door; until 1695, London was the only city in England. In the late 1580s, one Eleanor White, daughter to artist and explorer John White, was married in St Bride's, to the tiler and bricklayer Ananias Dare, their daughter Virginia Dare was to be the first English child born in North America. She was born on Roanoke Island on 18 August 1587: "Elenora, daughter to the governour and wife to Ananias Dare, one of the assistants, was delivered of a daughter in Roanoke"; the child was healthy and "was christened there the Sunday following, because this childe was the first Christian borne in Virginia, she was named Virginia".
A modern bust of Virginia Dare stands near the font replacing an earlier monument, stolen and has not been recovered. In the mid-17th century disaster struck. In 1665, the Great Plague of London killed 238 parishioners in a single week, in 1666, the following year, the church was destroyed during the Great Fire of London, which burned much of the city. After the fire, the old church was replaced by an new building designed by Sir Christopher Wren, one of his largest and most expensive works, taking seven years to build. St Bride's was reopened on 19 December 1675; the famous spire was added in 1701–1703. It measured 234 ft, but lost its upper eight feet to a lightning strike in 1764; the design utilises four octagonal stages of diminishing height, capped with an obelisk which terminates in a ball and vane. Buried at St Bride's is Robert Levet, a Yorkshireman who became a Parisian waiter a "practicer of physick" who ministered to the denizens of London's seedier neighbourhoods. Having been duped into a bad marriage, the hapless Levet was taken in by the author Samuel Johnson who wrote his poem "On the Death of Mr. Robert Levet", eulogising his good friend and tenant of many years.
Buried at St Bride's are the organist and composer, Thomas Weelkes and the poet, Richard Lovelace, as well as author Samuel Richardson The wedding cake is said to date back to 1703 when Thomas Rich, a baker’s apprentice from Ludgate Hill, fell in love with the daughter of his employer and asked her to marry him. He wanted to make an extravagant cake, drew on the design of St Bride's Church for inspiration. On the night of 29 December 1940, during the Blitz of central London in the Second World War, the church was gutted by fire-bombs dropped by the Luftwaffe; that night 1,500 fires were started, including three major conflagrations, leading to a fire storm, an event dubbed the Second Great Fire of London, due to the enormous amount of damage caused. St Paul's Cathedral itself was only saved by the dedication of the London firemen who kept the fire away from the cathedral and the volunteer firewatchers of the St Paul's Watch who fought to keep the flames from firebombs on the roof from spreading.
After the war, St Bride's was rebuilt at the expense of newspaper journalists. One fortunate and unintended consequence of the bombing was the excavation of the church's original 6th century Saxon foundations. Today, the crypt known as the Museum of Fleet Street is open to the public and contains a number of ancient relics, including Roman coins and medieval stained glass. Post-war excavations uncovered nearly 230 lead coffins with plaques dating from the 17th, 18th and early 19th centuries, filled with the bones of parishioners; the church was designated a Grade I listed building on 4 January 1950. In September 2007 the former rector, Archdeacon the Venerable David Meara, announced a special appeal to raise 3.5 million GBP to preserve the church's unique heritage and on November 2007 Queen Elizabeth II was guest of honour at a service to celebrate the fiftieth anniversary of the restoration work necessary after the Second World War. In March 2012 The Inspire! Appeal was launched to raise the at least £2.5m needed to repair the crumbling stonework of the church's famous spire.
The church has a place in sport, as the wor
Chitenay
Chitenay is a commune in the Loir-et-Cher department of central France. Denis Papin, physicist and inventor Communes of the Loir-et-Cher department INSEE statistics
Pressure cooking
Pressure cooking is the process of cooking food, using water or other cooking liquid, in a sealed vessel known as a pressure cooker. This simulates the effects of long braising within a shorter time. Any food that can be cooked in steam or water-based liquids can be cooked in a pressure cooker; the cooker works by trapping the steam produced from boiling the cooking liquid inside the vessel. This causes internal temperature to rise quickly. After use, the steam is released so that the vessel can be opened safely. In 1679, French physicist Denis Papin, better known for his studies on steam, invented the steam digester in an attempt to reduce the cooking time of food, his airtight cooker used steam pressure to raise the water's boiling point, thus cooking food more quickly. In 1681 Papin presented his invention to the Royal Society of London as a scientific study, he was elected a member. In 1864, Georg Gutbrod of Stuttgart began manufacturing pressure cookers made of tinned cast iron. In 1918, Spain granted a patent for the pressure cooker to Jose Alix Martínez from Zaragoza.
Martínez named it the olla exprés "express cooking pot", under patent number 71143 in the Boletín Oficial de la Propiedad Industrial. In 1924, the first pressure cooking pot recipe book was published, written by José Alix and titled "360 fórmulas de cocina Para guisar con la'olla expres'", or 360 recipes for cooking with a pressure cooker. In 1938, Alfred Vischer presented the Flex-Seal Speed Cooker, in New York City. Vischer's pressure cooker was the first designed for home use, its success led to competition among American and European manufacturers. At the 1939 New York World's Fair, the National Pressure Cooker Company renamed National Presto Industries, introduced its own pressure cooker. Known as "old type" pressure cookers, these operate with a weight-modified or "jiggler" valve, which releases pressure during operation; some people consider them loud. Older pressure cookers offered only one pressure level, but from the 1960s onwards some allow the operator to change the weight of the valve, thus changing the pressure.
Today, most pressure cookers are variations on the first-generation cookers, with the addition of new safety features such as a mechanism that prevents the cooker from being opened until it is depressurized. These operate with a spring-loaded valve, hidden from view in a proprietary mechanism; this generation is characterized by two or more pressure settings. Some of these pressure cookers do not release any steam during operation and instead use a rising indicator with markings to show the pressure level; these only release steam when the pan is opened, or as a safety precaution if the heat source is not reduced enough when the pan reaches the required cooking pressure. Others use a dial that the operator can advance by a few clicks to change the pressure setting or release pressure. After the stove-top pressure cookers, in 1991 came the electric pressure cookers, called the "third generation" pressure cookers; these include an electric heat source, automatically regulated to maintain the operating pressure.
They include a spring-loaded valve. This type of pressure cooker cannot be opened with a cold water quick-release method and should be operated with caution when releasing vapour through the valve while cooking foamy foods and liquids An electric pressure cooker integrates a timer. Depending on cooking control capability, there are three generations of electric pressure cookers: First-generation Electric, with mechanical timer. There is no delayed cooking capability. Second-generation Electric, with digital controller. Delayed cooking becomes possible and the controller shows a countdown timer when working pressure is reached. Third-generation Electric, with smart programming, which includes pre-set cooking times and settings based on heating intensity, temperature and duration; some cookers are multifunctional: pressure cooker, saute/browning, slow cooker, rice cooker, yogurt maker, sous vide and stockpot warmer that can be used to keep cooked food warm. In an ordinary, non-pressurized cooking vessel, the boiling point of water is 100 °C at standard pressure.
In a sealed pressure cooker, the boiling point of water increases as the pressure rises, resulting in superheated water. At a pressure of 1 bar or 100 kPa above the existing atmospheric pressure, water in a pressure cooker will reach a temperature of 121 °C; the boiling temperature of water is determined by the ambient atmospheric pressure. Pressure cookers always require liquid. Inside a pressure cooker, once the water is boiling and the steam is trapped, the pressure from the steam increases and pushes on the liquid, which increases its boiling temperature; the heat applied to the liquid by the heat source continues to create more steam pressure, increases the temperature of the liquid. Both the liquid and steam are at the same temperature. Once the selected pressure level is reached, the pressure regulator on the lid releases any excess steam, the heat can be lowered to maintain the pressure and save energy, since the pressure will increase no further; as a general rule, increasing the temperature of chemical reactions by 10 degrees doubles the rate of reaction.
Thus a pressure cooker, which can maintain an
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