A thermometer is a device that measures temperature or a temperature gradient. A thermometer has two important elements: a temperature sensor in which some change occurs with a change in temperature. Thermometers are used in technology and industry to monitor processes, in meteorology, in medicine, in scientific research; some of the principles of the thermometer were known to Greek philosophers of two thousand years ago. The modern thermometer evolved from the thermoscope with the addition of a scale in the early 17th century and standardisation through the 17th and 18th centuries. While an individual thermometer is able to measure degrees of hotness, the readings on two thermometers cannot be compared unless they conform to an agreed scale. Today there is an absolute thermodynamic temperature scale. Internationally agreed temperature scales are designed to approximate this based on fixed points and interpolating thermometers; the most recent official temperature scale is the International Temperature Scale of 1990.
It extends from 0.65 K to 1,358 K. Various authors have credited the invention of the thermometer to Hero of Alexandria; the thermometer was not a single invention, but a development. Hero of Alexandria knew of the principle that certain substances, notably air and contract and described a demonstration in which a closed tube filled with air had its end in a container of water; the expansion and contraction of the air caused the position of the water/air interface to move along the tube. Such a mechanism was used to show the hotness and coldness of the air with a tube in which the water level is controlled by the expansion and contraction of the gas; these devices were developed by several European scientists in the 16th and 17th centuries, notably Galileo Galilei. As a result, devices were shown to produce this effect reliably, the term thermoscope was adopted because it reflected the changes in sensible heat; the difference between a thermoscope and a thermometer is. Though Galileo is said to be the inventor of the thermometer, what he produced were thermoscopes.
The first clear diagram of a thermoscope was published in 1617 by Giuseppe Biancani: the first showing a scale and thus constituting a thermometer was by Robert Fludd in 1638. This was a vertical tube, closed by a bulb of air at the top, with the lower end opening into a vessel of water; the water level in the tube is controlled by the expansion and contraction of the air, so it is what we would now call an air thermometer. The first person to put a scale on a thermoscope is variously said to be Francesco Sagredo or Santorio Santorio in about 1611 to 1613; the word thermometer first appeared in 1624 in La Récréation Mathématique by J. Leurechon, who describes one with a scale of 8 degrees; the word comes from the Greek words θερμός, meaning "hot" and μέτρον, meaning "measure". The above instruments suffered from the disadvantage that they were barometers, i.e. sensitive to air pressure. In 1629, Joseph Solomon Delmedigo, a student of Galileo, published what is the first description and illustration of a sealed liquid-in-glass thermometer.
It is described as having a bulb at the bottom of a sealed tube filled with brandy. The tube has a numbered scale. Delmedigo does not claim to have invented this instrument, nor does he name anyone else as its inventor. In about 1654 Ferdinando II de' Medici, Grand Duke of Tuscany produced such an instrument, the first modern-style thermometer, dependent on the expansion of a liquid, independent of air pressure. Many other scientists experimented with various designs of thermometer. However, each inventor and each thermometer was unique—there was no standard scale. In 1665 Christiaan Huygens suggested using the melting and boiling points of water as standards, in 1694 Carlo Renaldini proposed using them as fixed points on a universal scale. In 1701, Isaac Newton proposed a scale of 12 degrees between the melting point of ice and body temperature. In 1714 Dutch scientist and inventor Daniel Gabriel Fahrenheit invented the first reliable thermometer, using mercury instead of alcohol and water mixtures.
In 1724 he proposed a temperature scale. He could do this because he manufactured thermometers, using mercury for the first time and the quality of his production could provide a finer scale and greater reproducibility, leading to its general adoption. In 1742, Anders Celsius proposed a scale with zero at the boiling point and 100 degrees at the freezing point of water, though the scale which now bears his name has them the other way around. French entomologist René Antoine Ferchault de Réaumur invented an alcohol thermometer and temperature scale in 1730 that proved to be less reliable than Fahrenheit's mercury thermometer; the first physician that put thermometer measurements to clinical practice was Herman Boerhaave. In 1866, Sir Thomas Clifford Allbutt invented a clinical thermometer that produced a body temperature reading in five minutes as opposed to twenty. In 1999, Dr. Francesco Pompei of the Exergen Corporation introduced the world's first temporal artery thermometer, a non-
Claude Louis Berthollet
Claude Louis Berthollet was a Savoyard-French chemist who became vice president of the French Senate in 1804. He is known for his scientific contributions to theory of chemical equilibria via the mechanism of reverse chemical reactions, for his contribution to modern chemical nomenclature. On a practical basis, Berthollet was the first to demonstrate the bleaching action of chlorine gas, was first to develop a solution of sodium hypochlorite as a modern bleaching agent. Claude Louis Berthollet was born in Talloires, near Annecy part of the Duchy of Savoy, in 1749, he started his studies at Chambéry and in Turin where he graduated in medicine. Berthollet's great new developments in works regarding chemistry made him, in a short period of time, an active participant of the Academy of Science in 1780. Berthollet, along with Antoine Lavoisier and others, devised a chemical nomenclature, or a system of names, which serves as the basis of the modern system of naming chemical compounds, he carried out research into dyes and bleaches, being first to introduce the use of chlorine gas as a commercial bleach in 1785.
He first produced a modern bleaching liquid in 1789 in his laboratory on the quay Javel in Paris, France, by passing chlorine gas through a solution of sodium carbonate. The resulting liquid, known as "Eau de Javel", was a weak solution of sodium hypochlorite. Another strong chlorine oxidant and bleach which he investigated and was the first to produce, potassium chlorate, is known as Berthollet's Salt. Berthollet first determined the elemental composition of the gas ammonia, in 1785. Berthollet was one of the first chemists to recognize the characteristics of a reverse reaction, hence, chemical equilibrium. Berthollet was engaged in a long-term battle with another French chemist, Joseph Proust, on the validity of the law of definite proportions. While Proust believed that chemical compounds are composed of a fixed ratio of their constituent elements irrespective of the methods of production, Berthollet believed that this ratio can change according to the ratio of the reactants taken. Although Proust proved his theory by accurate measurements, his theory was not accepted due to Berthollet's authority.
His law was accepted when Berzelius confirmed it in 1811. But it was found that Berthollet was not wrong because there exists a class of compounds that do not obey the law of definite proportions; these non-stoichiometric compounds are named berthollides in his honor. Berthollet was one of several scientists who went with Napoleon to Egypt, was a member of the physics and natural history section of the Institut d'Égypte. In April, 1789 Berthollet was elected a Fellow of the Royal Society of London. In 1801, he was elected a foreign member of the Royal Swedish Academy of Sciences. In 1809, Berthollet was elected an associate member first class of the Royal Institute of the Netherlands, predecessor of the Royal Netherlands Academy of Arts and Sciences, he was elected an Honorary Fellow of the Royal Society of Edinburgh in 1820 and a Foreign Honorary Member of the American Academy of Arts and Sciences in 1822. Claude-Louis Berthollet's 1788 publication entitled Méthode de Nomenclature Chimique, published with colleagues Antoine Lavoisier, Louis Bernard Guyton de Morveau, Antoine François, comte de Fourcroy, was honored by a Citation for Chemical Breakthrough Award from the Division of History of Chemistry of the American Chemical Society, presented at the Académie des Sciences in 2015.
Berthollet married Marguerite Baur in 1788. Berthollet was an accused of being an atheist, he died in Arcueil, France in 1822. Society of the Friends of Truth Satish, Kapoor. "Berthollet, Claude Louis". Dictionary of Scientific Biography. 2. New York: Charles Scribner's Sons. Pp. 73–82. ISBN 978-0-684-10114-9. N. S. Kurnakow. "Singuläre Punkte chemischer Diagramme.". Zeitschrift für anorganische und allgemeine Chemie. 146: 69–102. Doi:10.1002/zaac.19251460105. Barbara Whitney Keyser. "Between science and craft: The case of berthollet and dyeing". Zeitschrift für anorganische und allgemeine Chemie. 47: 213–260. Doi:10.1080/00033799000200211. Charles Coulston Gillispie. "Scientific Aspects of the French Egyptian Expedition 1798-1801". Proceedings of the American Philosophical Society. 133: 447–474. JSTOR 986871. H. E. Le Grand. "Berthollet's Essai de statique chimique and Acidity". Isis. 67: 229–238. Doi:10.1086/351586. JSTOR 230924. Swain P. A.. "Hypochlorite bleaches in the textile industry: a history". School science review.
82: 65–71. Doi:10.1080/00033797900200141 Works by Claude-Louis Berthollet at Project Gutenberg Works by or about Claude Louis Berthollet at Internet Archive
Alexander von Humboldt
Friedrich Wilhelm Heinrich Alexander von Humboldt was a Prussian polymath, naturalist and influential proponent of Romantic philosophy and science. He was the younger brother of the Prussian minister and linguist Wilhelm von Humboldt. Humboldt's quantitative work on botanical geography laid the foundation for the field of biogeography. Humboldt's advocacy of long-term systematic geophysical measurement laid the foundation for modern geomagnetic and meteorological monitoring. Between 1799 and 1804, Humboldt travelled extensively in the Americas and describing them for the first time from a modern scientific point of view, his description of the journey was written up and published in an enormous set of volumes over 21 years. Humboldt was one of the first people to propose that the lands bordering the Atlantic Ocean were once joined. Humboldt resurrected the use of the word cosmos from the ancient Greek and assigned it to his multivolume treatise, Kosmos, in which he sought to unify diverse branches of scientific knowledge and culture.
This important work motivated a holistic perception of the universe as one interacting entity. He was the first person to describe the phenomenon and cause of human-induced climate change, in 1800 and again in 1831, based on observations generated during his travels. Alexander von Humboldt was born in Berlin in Prussia on 14 September 1769, he was baptized with the Duke of Brunswick serving as godfather. Humboldt's father, Alexander Georg von Humboldt, belonged to a prominent Pomeranian family, although not one of the titled gentry, a major in the Prussian Army, who had served with the Duke of Brunswick. At age 42, Alexander Georg was rewarded for his services in the Seven Years' War with the post of royal chamberlain, he profited from the contract to lease state lotteries and tobacco sales. He first married the daughter of Prussian General Adjutant Schweder. In 1766, Alexander Georg married Maria Elisabeth Colomb, a well-educated woman and widow of Baron Hollwede, with whom she had a son. Alexander Georg and Maria Elisabeth had three children, a daughter, who died young, two sons and Alexander.
Her first-born son and Alexander's half-brother, was something of a ne'er do well, not mentioned in the family history. Alexander Georg died in 1779, leaving the brothers Humboldt in the care of their distant mother, she did have high ambitions for Alexander and his older brother Wilhelm, hiring excellent tutors, who were Enlightenment thinkers, including Kantian physician Marcus Herz and botanist Karl Ludwig Willdenow, who became one of the most important botanists in Germany. Humboldt's mother expected them to become civil servants of the Prussian state; the money Baron Holwede left to Alexander's mother became, after her death, instrumental in funding Alexander's explorations, contributing more than 70% of his private income. Due to his youthful penchant for collecting and labeling plants and insects, Alexander received the playful title of "the little apothecary". Marked for a political career, Alexander studied finance for six months in 1787 at the University of Frankfurt, which his mother might have chosen less for its academic excellence than its closeness to their home in Berlin.
On 25 April 1789, he matriculated at Göttingen known for the lectures of C. G. Heyne and anatomist J. F. Blumenbach, his brother Wilhelm was a student at Göttingen, but they did not interact much, since their intellectual interests were quite different. His vast and varied interests were by this time developed. At Gottingen, he met Georg Forster, a naturalist, with Captain James Cook on his second voyage. Humboldt traveled with Forster in Europe; the two traveled to England, Humboldt's first sea voyage, the Netherlands, France. In England, he met Sir Joseph Banks, president of the Royal Society, who had traveled with Captain Cook; the scientific friendship between Banks and Humboldt lasted until Banks's death in 1820, the two shared botanical specimens for study. Banks mobilized his scientific contacts in years to aid Humboldt's work. Humboldt's scientific excursion up the Rhine resulted in his 1790 treatise Mineralogische Beobachtungen über einige Basalte am Rhein. Humboldt's passion for travel was of long standing.
Humboldt's talents were devoted to the purpose of preparing himself as a scientific explorer. With this emphasis, he studied commerce and foreign languages at Hamburg, geology at Technische Universität Bergakademie Freiberg in 1791 under A. G. Werner, leader of the Neptunist school of geology. C. Loder. X. von Zach and J. G. Köhler. At Freiberg, he met a number of men who were to prove important to him in his career, including Spaniard Manuel del Rio, who became director of the School of Mines the crown established in Mexico. During this period, his brother Wilhelm married. Humboldt graduated from the Freiberg School of Mines in 1792 and was appointed to a Prussian government position in the Department of Mines as an inspector in Bayreuth and the Fichtel mountains. Humboldt was excellent at his job, with production of gold ore in his first year outstripping the previous eight years. During his period as a mine inspector, Humbo
Reign of Terror
The Reign of Terror, or The Terror, refers to a period during the French Revolution after the First French Republic was established. Several historians consider the "reign of terror" to have begun in 1793, placing the starting date at either 5 September, June or March, while some consider it to have begun in September 1792, or July 1789, but there is a consensus that it ended with the fall of Maximilien Robespierre in July 1794. Between June 1793 and the end of July 1794, there were 16,594 official death sentences in France, of which 2,639 were in Paris. There was a sense of emergency among leading politicians in France in the summer of 1793 between the widespread civil war and counter-revolution. Bertrand Barère exclaimed on 5 September 1793 in the Convention: "Let's make terror the order of the day!" They were determined to avoid street violence such as the September Massacres of 1792 by taking violence into their own hands as an instrument of government. Robespierre in February 1794 in a speech explained the necessity of terror: If the basis of popular government in peacetime is virtue, the basis of popular government during a revolution is both virtue and terror.
Terror is nothing more than speedy and inflexible justice. Some historians argue. Others suggest there were additional causes, including emotional. Enlightenment thought emphasized the importance of rational thinking and began challenging legal and moral foundations of society, providing the leaders of the Terror with new ideas about the role and structure of government. Rousseau's Social Contract argued that each person was born with rights, they would come together to form a government that would protect those rights. Under the social contract, the government was required to act for the general will, which represented the interests of everyone rather than a few factions. Drawing from the idea of a general will, Robespierre felt that the French Revolution could result in a Republic built for the general will but only once those who fought this ideal were expelled; those who resisted the government were deemed "tyrants" fighting against the virtue and honor of the general will. The leaders felt their ideal version of government was threatened from the inside and outside of France, terror was the only way to preserve the dignity of the Republic created from French Revolution.
Robespierre's ideology was not derived from Rousseau. The writings of another Enlightenment thinker of the time, Baron de Montesquieu influenced Robespierre. One of Montesquieu's writings, The Spirit of the Laws, defines a core principle of a democratic government: virtue, he describes it as "the love of laws and of our country." In Robespierre's speech to the National Convention on 5 February 1794, On Political Morality, he talks about virtue being the "fundamental principle of popular or democratic government." This was, in fact, the same virtue defined by Montesquieu 50 years earlier. Robespierre believed that the virtue needed for any democratic government was lacking in the French people; as a result, he decided to weed out those. The result was a continual push towards Terror; the Convention used this as justification for the course of action to "crush the enemies of the revolution... let the laws be executed, … and let liberty be saved."These members of the Enlightenment movement influenced revolutionary leaders.
Voltaire's warnings were overlooked, though some of his ideas were used for justification of the Revolution and the start of the Terror. He protested against Catholic Dogmas and the ways of Christianity stating, "of all religions, the Christian should of course inspire the most toleration, but till now the Christians have been the most intolerant of all men." These criticisms were used by Robespierre and other leaders as justification for their anti-religious reforms. Voltaire laid down some warnings. In his Philosophical Dictionary, he states, "we are all steeped in error. After the beginning of the French Revolution, the surrounding monarchies did not show great hostility towards the rebellion. Though ignored, Louis XVI was able to find support in Leopold II of Austria and Frederick William II of Prussia. On 27 August 1791, these foreign leaders made the Pillnitz Declaration saying they would restore the French monarch if other European rulers joined. In response to what they viewed to be the meddling of foreign powers, France declared war on 20 April 1792.
However, at this point, the war was only Austria against France. France began this war with a large series of defeats which set a precedent of fear of invasion in the people that would last throughout the war. Massive reforms of military institutions, while effective in the long run, presented the initial problems of inexperienced forces and leaders of questionable political loyalty. In the time it took for officers of merit to use their new freedoms to climb the chain of command, France suffered. Many of the early battles were definitive losses for the Fren
Ideal gas law
The ideal gas law called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations, it was first stated by Émile Clapeyron in 1834 as a combination of the empirical Boyle's law, Charles's law, Avogadro's law, Gay-Lussac's law. The ideal gas law is written as P V = n R T, where P, V and T are the pressure and absolute temperature, it is the same for all gases. It can be derived from the microscopic kinetic theory, as was achieved by August Krönig in 1856 and Rudolf Clausius in 1857; the state of an amount of gas is determined by its pressure and temperature. The modern form of the equation relates these in two main forms; the temperature used in the equation of state is an absolute temperature: the appropriate SI unit is the kelvin. The most introduced form is P V = n R T = N k B T, where: P is the pressure of the gas, V is the volume of the gas, n is the amount of substance of gas, N is the number of gas molecules, R is the ideal, or universal, gas constant, equal to the product of the Boltzmann constant and the Avogadro constant, k B is the Boltzmann constant T is the absolute temperature of the gas.
In SI units, P is measured in pascals, V is measured in cubic metres, n is measured in moles, T in kelvins. R has the value 8.314 J/ ≈ 2 cal/, or 0.08206 L·atm/. How much gas is present could be specified by giving the mass instead of the chemical amount of gas. Therefore, an alternative form of the ideal gas law may be useful; the chemical amount is equal to total mass of the gas divided by the molar mass: n = m M. By replacing n with m/M and subsequently introducing density ρ = m/V, we get: P V = m M R T P = m V R T M P = ρ R M T Defining the specific gas constant Rspecific as the ratio R/M, P = ρ R specific T This form of the ideal gas law is useful because it links pressure and temperature in a unique formula independent of the quantity of the considered gas. Alternatively, the law may be written in terms of the specific volume v, the reciprocal of density, as P v = R specific T, it is common in engineering applications, to represent the specific gas constant by the symbol R. In such cases, the universal gas constant is given a different symbol such as R ¯ to distinguish it.
In any case, the context and/or units of the gas constant should make it clear as to whether the universal or specific gas constant is being referred to. In statistical mechanics the following molecular equation is derived from first principles P = n k B T, where P is the absolute pressure of the gas, n is the number of molecules in the given volume V, T is the absolute temperature, kB is the Boltzmann constant relating temperature and energy, given by: k B = R N A where NA is the Avogadro constant. From this we notice that for a gas of mass m, with an average particle mass of μ times the atomic mass constant, mu, the number of molecules will be given by N = m μ m u, since ρ = m/V = nμmu, we find that the ideal gas law can be rewritten as P = 1 V m μ m u k B T = k B μ m u ρ T. In SI units, P is measured in pascals, V in cubic metre
École des ponts ParisTech
École des Ponts ParisTech is a university-level institution of higher education and research in the field of science and technology. Founded in 1747 by Daniel-Charles Trudaine, it is one of the oldest and one of the most prestigious French Grandes Écoles, its primary mission has been to train engineering officials and civil engineers but the school now offers a wide-ranging education including computer science, applied mathematics, civil engineering, finance, innovation, urban studies and transport engineering. École des Ponts is today international: 43% of its students obtain a double degree abroad, 30% of an ingénieur cohort is foreign. It is headquartered in Marne-la-Vallée, is a founding member of ParisTech and of the Paris School of Economics; the school is under the Ministry of Sustainable Development and Energy of France. Following the creation of the Corps of Bridges and Roads in 1716, the King's Council decided in 1747 to found a specific training course for the state's engineers, as École royale des ponts et chaussées.
In 1775, the school took its current name as École nationale des ponts et chaussées, by Daniel-Charles Trudaine, in a moment when the state decided to set up a progressive and efficient control of the building of roads and canals, in the training of civil engineers. The school's first director, from 1747 until 1794, was Jean-Rodolphe Perronet, civil service administrator and a contributor to the Encyclopédie of Denis Diderot and Jean le Rond d'Alembert. Without lecturer, fifty students taught themselves geometry, algebra and hydraulics. Visits of building sites, cooperations with scientists and engineers and participation to the drawing of the map of the kingdom used to complete their training, four to twelve years long. During the First French Empire run by Napoleon I from 1804 to 1814, a number of members of the Corps of Bridges and Roads took part in the reconstruction of the French road network that had not been maintained during the Revolution, in large infrastructural developments, notably hydraulic projects.
Under the orders of the emperor, French scientist Gaspard Riche de Prony, second director of the school from 1798 to 1839, adapts the education provided by the school in order to improve the training of future civil engineers, whose purpose is to rebuild the major infrastructures of the country: roads, but administrative buildings and fortifications. Prony is now considered as a influential figure of the school. During the twenty years that followed the First Empire, the experience of the faculty and the alumni involved in the reconstruction influenced its training methods and internal organisation. In 1831, the school opens its first laboratory, which aims at concentrating the talents and experiences of the country's best civil engineers; the school gradually becomes a place of reflection and debates for urban planning. As a new step in the evolution of the school, the decree of 1851 insists on the organisation of the courses, the writing of an annual schedule, the quality of the faculty, the control of the students’ works.
For the first time in its history, the school opens its doors to a larger public. At this time, in France, the remarkable development of transports, roads and canals is influenced by engineers from the school, who modernised the country by creating the large traffic networks, admired in several European countries. After the Second World War, the school focused on developing the link between economics and engineering; as civil engineering was requiring higher financial investments, the state needed engineers to be able to understand the economic situation of post-war Europe. From on, the program of the school had three different aspects: scientific and technic and economic; the number of admitted students increased in order to provide both the Corps of Bridges and Roads and the private sector trained young engineers. At the time, technical progress and considerable development of sciences and techniques used in building and the protection of the environment imposed a change of strategy in the training programme.
More specialisations were progressively created and the overall programme was adapted to national issues. École des Ponts ParisTech offers high-level programmes in an extensive range of fields, with traditional competences in mathematics, computer science, civil engineering, economics, environment, town & regional planning and innovation. École des Ponts ParisTech is among the schools called "généralistes", which means that students receive a broad, management-oriented and non-specialised education. The school offers specialized/research masters and PhDs, it has opened a design school, with programmes in innovation and startup creation. This undergraduate-graduate engineering programme is the original and main programme offered by the school, it is quite different from typical university or college studies and specific to the French system of Grandes Écoles. The Ingénieur degree of École des Ponts – the Diplôme d'Ingénieur – is equivalent to a Master of Science. Admissions for engineering students is done
Paris is the capital and most populous city of France, with an area of 105 square kilometres and an official estimated population of 2,140,526 residents as of 1 January 2019. Since the 17th century, Paris has been one of Europe's major centres of finance, commerce, fashion and the arts; the City of Paris is the centre and seat of government of the Île-de-France, or Paris Region, which has an estimated official 2019 population of 12,213,364, or about 18 percent of the population of France. The Paris Region had a GDP of €681 billion in 2016, accounting for 31 percent of the GDP of France, was the 5th largest region by GDP in the world. According to the Economist Intelligence Unit Worldwide Cost of Living Survey in 2018, Paris was the second most expensive city in the world, after Singapore, ahead of Zurich, Hong Kong and Geneva. Another source ranked Paris as most expensive, on a par with Singapore and Hong-Kong, in 2018; the city is a major rail and air-transport hub served by two international airports: Paris-Charles de Gaulle and Paris-Orly.
Opened in 1900, the city's subway system, the Paris Métro, serves 5.23 million passengers daily, is the second busiest metro system in Europe after Moscow Metro. Gare du Nord is the 24th busiest railway station in the world, the first located outside Japan, with 262 million passengers in 2015. Paris is known for its museums and architectural landmarks: the Louvre was the most visited art museum in the world in 2018, with 10.2 million visitors. The Musée d'Orsay and Musée de l'Orangerie are noted for their collections of French Impressionist art, the Pompidou Centre Musée National d'Art Moderne has the largest collection of modern and contemporary art in Europe; the historical district along the Seine in the city centre is classified as a UNESCO Heritage Site. Popular landmarks in the centre of the city include the Cathedral of Notre Dame de Paris and the Gothic royal chapel of Sainte-Chapelle, both on the Île de la Cité. Paris received 23 million visitors in 2017, measured by hotel stays, with the largest numbers of foreign visitors coming from the United States, the UK, Germany and China.
It was ranked as the third most visited travel destination in the world in 2017, after Bangkok and London. The football club Paris Saint-Germain and the rugby union club Stade Français are based in Paris; the 80,000-seat Stade de France, built for the 1998 FIFA World Cup, is located just north of Paris in the neighbouring commune of Saint-Denis. Paris hosts the annual French Open Grand Slam tennis tournament on the red clay of Roland Garros. Paris will host the 2024 Summer Olympics; the 1938 and 1998 FIFA World Cups, the 2007 Rugby World Cup, the 1960, 1984, 2016 UEFA European Championships were held in the city and, every July, the Tour de France bicycle race finishes there. The name "Paris" is derived from the Celtic Parisii tribe; the city's name is not related to the Paris of Greek mythology. Paris is referred to as the City of Light, both because of its leading role during the Age of Enlightenment and more because Paris was one of the first large European cities to use gas street lighting on a grand scale on its boulevards and monuments.
Gas lights were installed on the Place du Carousel, Rue de Rivoli and Place Vendome in 1829. By 1857, the Grand boulevards were lit. By the 1860s, the boulevards and streets of Paris were illuminated by 56,000 gas lamps. Since the late 19th century, Paris has been known as Panam in French slang. Inhabitants are known in French as Parisiens, they are pejoratively called Parigots. The Parisii, a sub-tribe of the Celtic Senones, inhabited the Paris area from around the middle of the 3rd century BC. One of the area's major north–south trade routes crossed the Seine on the île de la Cité; the Parisii minted their own coins for that purpose. The Romans began their settlement on Paris' Left Bank; the Roman town was called Lutetia. It became a prosperous city with a forum, temples, an amphitheatre. By the end of the Western Roman Empire, the town was known as Parisius, a Latin name that would become Paris in French. Christianity was introduced in the middle of the 3rd century AD by Saint Denis, the first Bishop of Paris: according to legend, when he refused to renounce his faith before the Roman occupiers, he was beheaded on the hill which became known as Mons Martyrum "Montmartre", from where he walked headless to the north of the city.
Clovis the Frank, the first king of the Merovingian dynasty, made the city his capital from 508. As the Frankish domination of Gaul began, there was a gradual immigration by the Franks to Paris and the Parisian Francien dialects were born. Fortification of the Île-de-la-Citie failed to avert sacking by Vikings in 845, but Paris' strategic importance—with its bridges prevent