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
An electric light is a device that produces visible light from electric current. It is the most common form of artificial lighting and is essential to modern society, providing interior lighting for buildings and exterior light for evening and nighttime activities. In technical usage, a replaceable component that produces light from electricity is called a lamp. Lamps are called light bulbs. Lamps have a base made of ceramic, glass or plastic, which secures the lamp in the socket of a light fixture; the electrical connection to the socket may be made with a screw-thread base, two metal pins, two metal caps or a bayonet cap. The three main categories of electric lights are incandescent lamps, which produce light by a filament heated white-hot by electric current, gas-discharge lamps, which produce light by means of an electric arc through a gas, LED lamps, which produce light by a flow of electrons across a band gap in a semiconductor. Before electric lighting became common in the early 20th century, people used candles, gas lights, oil lamps, fires.
English chemist Humphry Davy developed the first incandescent light in 1802, followed by the first practical electric arc light in 1806. By the 1870s, Davy's arc lamp had been commercialized, was used to light many public spaces. Efforts by Swan and Edison led to commercial incandescent light bulbs becoming available in the 1880s, by the early twentieth century these had replaced arc lamps; the energy efficiency of electric lighting has increased radically since the first demonstration of arc lamps and the incandescent light bulb of the 19th century. Modern electric light sources come in a profusion of types and sizes adapted to many applications. Most modern electric lighting is powered by centrally generated electric power, but lighting may be powered by mobile or standby electric generators or battery systems. Battery-powered light is reserved for when and where stationary lights fail in the form of flashlights, electric lanterns, in vehicles. Types of electric lighting include: Incandescent light bulb, a heated filament inside a glass envelope Halogen lamps are incandescent lamps that use a fused quartz envelope filled with halogen gas LED lamp, a solid-state lamp that uses light-emitting diodes as the source of light Arc lamp Xenon arc lamp Mercury-xenon arc lamp Ultra-high-performance lamp, an ultra-high-pressure mercury-vapor arc lamp for use in movie projectors Metal-halide lamp Gas-discharge lamp, a light source that generates light by sending an electric discharge through an ionized gas Fluorescent lamp Compact fluorescent lamp, a fluorescent lamp designed to replace an incandescent lamp Neon lamp Mercury-vapor lamp Sodium-vapor lamp Sulfur lamp Electrodeless lamp, a gas discharge lamp in which the power is transferred from outside the bulb to inside via electromagnetic fieldsDifferent types of lights have vastly differing efficacies and color of light.
*Color temperature is defined as the temperature of a black body emitting a similar spectrum. The most efficient source of electric light is the low-pressure sodium lamp, it produces, for all practical purposes, a monochromatic orange-yellow light, which gives a monochromatic perception of any illuminated scene. For this reason, it is reserved for outdoor public lighting applications. Low-pressure sodium lights are favoured for public lighting by astronomers, since the light pollution that they generate can be filtered, contrary to broadband or continuous spectra; the modern incandescent light bulb, with a coiled filament of tungsten, commercialized in the 1920s, developed from the carbon filament lamp introduced about 1880. As well as bulbs for normal illumination, there is a wide range, including low voltage, low-power types used as components in equipment, but now displaced by LEDs Incandescent bulbs are being phased out in many countries due to their low energy efficiency. Less than 3% of the input energy is converted into usable light.
Nearly all of the input energy ends up as heat that, in warm climates, must be removed from the building by ventilation or air conditioning resulting in more energy consumption. In colder climates where heating and lighting is required during the cold and dark winter months, the heat byproduct has at least some value. Halogen lamps are much smaller than standard incandescent lamps, because for successful operation a bulb temperature over 200 °C is necessary. For this reason, most have a bulb of fused aluminosilicate glass; this is sealed inside an additional layer of glass. The outer glass is a safety precaution, to reduce ultraviolet emission and to contain hot glass shards should the inner envelope explode during operation. Oily residue from fingerprints may cause a hot quartz envelope to shatter due to excessive heat buildup at the contamination site; the risk of burns or fire is greater with bare bulbs, leading to their prohibition in some places, unless enclosed by the luminaire. Those designed for 12- or 24-volt operation have compact filaments, useful for good optical control.
They have higher efficacies and better lives than non-halogen types. The light output remains constant throughout their life. Fluorescent lamps consist of a glass tube that contains argon under low pressure. Electricity flowing through the tube causes the gases to give off ultraviolet energy; the inside of the tubes are coated with phosphors that give off visible light when struck by ultraviolet photons. They have much higher efficiency than incandescent lamps. For the same amount of light generated, they typic
Incandescent light bulb
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light. The filament is protected from oxidation with a glass or fused quartz bulb, filled with inert gas or a vacuum. In a halogen lamp, filament evaporation is slowed by a chemical process that redeposits metal vapor onto the filament, thereby extending its life; the light bulb is supplied with electric current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output, voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, work well on either alternating current or direct current; as a result, the incandescent bulb is used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, flashlights, for decorative and advertising lighting.
Incandescent bulbs are much less efficient than other types of electric lighting. The remaining energy is converted into heat; the luminous efficacy of a typical incandescent bulb for 120 V operation is 16 lumens per watt, compared with 60 lm/W for a compact fluorescent bulb or 150 lm/W for some white LED lamps. Some applications of the incandescent bulb deliberately use the heat generated by the filament; such applications include incubators, brooding boxes for poultry, heat lights for reptile tanks, infrared heating for industrial heating and drying processes, lava lamps, the Easy-Bake Oven toy. Incandescent bulbs have short lifetimes compared with other types of lighting. Incandescent bulbs have been replaced in many applications by other types of electric light, such as fluorescent lamps, compact fluorescent lamps, cold cathode fluorescent lamps, high-intensity discharge lamps, light-emitting diode lamps; some jurisdictions, such as the European Union, China and United States, are in the process of phasing out the use of incandescent light bulbs while others, including Colombia, Cuba and Brazil, have prohibited them already.
In addressing the question of who invented the incandescent lamp, historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Swan and Thomas Edison. They conclude that Edison's version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve and a high resistance that made power distribution from a centralized source economically viable. Historian Thomas Hughes has attributed Edison's success to his development of an entire, integrated system of electric lighting; the lamp was a small component in his system of electric lighting, no more critical to its effective functioning than the Edison Jumbo generator, the Edison main and feeder, the parallel-distribution system. Other inventors with generators and incandescent lamps, with comparable ingenuity and excellence, have long been forgotten because their creators did not preside over their introduction in a system of lighting.
In 1761 Ebenezer Kinnersley demonstrated heating a wire to incandescence. In 1802, Humphry Davy used what he described as "a battery of immense size", consisting of 2,000 cells housed in the basement of the Royal Institution of Great Britain, to create an incandescent light by passing the current through a thin strip of platinum, chosen because the metal had an high melting point, it was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. Over the first three-quarters of the 19th century, many experimenters worked with various combinations of platinum or iridium wires, carbon rods, evacuated or semi-evacuated enclosures. Many of these devices were demonstrated and some were patented. In 1835, James Bowman Lindsay demonstrated a constant electric light at a public meeting in Dundee, Scotland, he stated that he could "read a book at a distance of one and a half feet". Lindsay, a lecturer at the Watt Institution in Dundee, Scotland, at the time, had developed a light, not combustible, created no smoke or smell and was less expensive to produce than Davy's platinum-dependent bulb.
However, having perfected the device to his own satisfaction, he turned to the problem of wireless telegraphy and did not develop the electric light any further. His claims are not well documented, although he is credited in Challoner et al. with being the inventor of the "Incandescent Light Bulb". In 1838, Belgian lithographer Marcellin Jobard invented an incandescent light bulb with a vacuum atmosphere using a carbon filament. In 1840, British scientist Warren de la Rue enclosed a coiled platinum filament in a vacuum tube and passed an electric current through it; the design was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain fewer gas molecules to react with the platinum, improving its longevity. Although a workable design, the cost of the platinum made it impractical for commercial use. In 1841, Frederick de Moleyns of England was granted the first patent for an incandescent lamp, with a design using platinum wires contained within a vacuum
A lottery is a form of gambling that involves the drawing of numbers at random for a prize. Lotteries are outlawed by some governments, while others endorse it to the extent of organizing a national or state lottery, it is common to find some degree of regulation of lottery by governments. Though lotteries were common in the United States and some other countries during the 19th century, by the beginning of the 20th century, most forms of gambling, including lotteries and sweepstakes, were illegal in the U. S. and most of Europe as well as many other countries. This remained so until well after World War II. In the 1960s casinos and lotteries began to re-appear throughout the world as a means for governments to raise revenue without raising taxes. Lotteries come in many formats. For example, the prize can be a fixed amount of cash or goods. In this format there is risk to the organizer. More the prize fund will be a fixed percentage of the receipts. A popular form of this is the "50–50" draw where the organizers promise that the prize will be 50% of the revenue.
Many recent lotteries allow purchasers to select the numbers on the lottery ticket, resulting in the possibility of multiple winners. The first recorded signs of a lottery are keno slips from the Chinese Han Dynasty between 205 and 187 BC; these lotteries are believed to have helped to finance major government projects like the Great Wall of China. From the Chinese "The Book of Songs" comes a reference to a game of chance as "the drawing of wood", which in context appears to describe the drawing of lots; the first known European lotteries were held during the Roman Empire as an amusement at dinner parties. Each guest would receive a ticket, prizes would consist of fancy items such as dinnerware; every ticket holder would be assured of winning something. This type of lottery, was no more than the distribution of gifts by wealthy noblemen during the Saturnalian revelries; the earliest records of a lottery offering tickets for sale is the lottery organized by Roman Emperor Augustus Caesar. The funds were for repairs in the City of Rome, the winners were given prizes in the form of articles of unequal value.
The first recorded lotteries to offer tickets for sale with prizes in the form of money were held in the Low Countries in the 15th century. Various towns held public lotteries to raise money for town fortifications, to help the poor; the town records of Ghent and Bruges indicate that lotteries may be older. A record dated 9 May 1445 at L'Ecluse refers to raising funds to build walls and town fortifications, with a lottery of 4,304 tickets and total prize money of 1737 florins. In the 17th century it was quite usual in the Netherlands to organize lotteries to collect money for the poor or in order to raise funds for all kinds of public usages; the lotteries proved popular and were hailed as a painless form of taxation. The Dutch state-owned Staatsloterij is the oldest running lottery; the English word lottery is derived from the Dutch noun "lot" meaning "fate". The first recorded Italian lottery was held on 9 January 1449 in Milan organized by the Golden Ambrosian Republic to finance the war against the Republic of Venice.
However, it was in Genoa that Lotto became popular. People used to bet on the name of Great Council members, who were drawn by chance, five out of ninety candidates every six months; this kind of gambling was called Semenaiu. When people wanted to bet more than twice a year, they began to substitute the candidates names with numbers and modern lotto was born, to which both modern legal lotteries and the illegal Numbers game can trace their ancestry. King Francis I of France discovered the lotteries during his campaigns in Italy and decided to organize such a lottery in his kingdom to help the state finances; the first French lottery, the Loterie Royale, was held in 1539 and was authorized with the edict of Châteaurenard. This attempt was a fiasco, since the tickets were costly and the social classes which could afford them opposed the project. During the two following centuries lotteries in France were forbidden or, in some cases, tolerated. Although the English first experimented with raffles and similar games of chance, the first recorded official lottery was chartered by Queen Elizabeth I, in the year 1566, was drawn in 1569.
This lottery was designed to raise money for the "reparation of the havens and strength of the Realme, towardes such other publique good workes". Each ticket holder won a prize, the total value of the prizes equalled the money raised. Prizes were in the form of other valuable commodities; the lottery was promoted by scrolls posted throughout the country showing sketches of the prizes. Thus, the lottery money received was an interest free loan to the government during the three years that the tickets were sold. In years, the government sold the lottery ticket rights to brokers, who in turn hired agents and runners to sell them; these brokers became the modern day stockbrokers for various commercial ventures. Most people could not afford the entire cost of a lottery ticket, so the brokers would sell shares in a ticket. Many private lotteries were held, including raising money for The Virginia Company of London to support its settlement in America at Jamestown; the English State Lottery ran from 1694 until 1826.
Thus, the English lotteries ran for over 250 years, until the government, under constant pressure from the opposition in p
Sir Humphry Davy, 1st Baronet was a Cornish chemist and inventor, best remembered today for isolating, using electricity, a series of elements for the first time: potassium and sodium in 1807 and calcium, barium and boron the following year, as well as discovering the elemental nature of chlorine and iodine. He studied the forces involved in these separations, inventing the new field of electrochemistry. In 1799 Davy experimented with nitrous oxide and was astonished at how it made him laugh, so he nicknamed it "laughing gas", wrote about its potential anaesthetic properties in relieving pain during surgery. Berzelius called Davy's 1806 Bakerian Lecture On Some Chemical Agencies of Electricity "one of the best memoirs which has enriched the theory of chemistry." Davy was a baronet, President of the Royal Society, Member of the Royal Irish Academy, Fellow of the Geological Society. He invented the Davy lamp and a early form of arc lamp, he joked. Davy was born in Penzance, Cornwall in England on 17 December, 1778.
Davy's brother, writes that the society of their hometown was characterised by "an unbounded credulity respecting the supernatural and monstrous... Amongst the middle and higher classes, there was little taste for literature, still less for science... Hunting, wrestling, cockfighting ending in drunkenness, were what they most delighted in". At the age of six, Davy was sent to the grammar school at Penzance. Three years his family moved to Varfell, near Ludgvan, subsequently, in term-time Davy boarded with John Tonkin, his godfather and his guardian. On leaving Penzance grammar school in 1793, Tonkin paid for Davy to attend Truro Grammar School in 1793 to finish his education under the Rev Dr Cardew, who, in a letter to Davies Gilbert, said dryly: "I could not discern the faculties by which he was afterwards so much distinguished." Yet, Davy entertained his school friends with writing poetry and telling stories from One Thousand and One Nights. Reflecting on his school days, in a letter to his mother, Davy wrote: "Learning is a true pleasure.
Davy said: "I consider it fortunate I was left much to myself as a child, put upon no particular plan of study... What I am I made myself." Davy's brother praises his "native vigour": "there belonged, however, to his mind, it cannot be doubted, the genuine quality of genius, or of that power of intellect which exalts its possessor above the crowd."After Davy's father died in 1794, Tonkin apprenticed him to John Bingham Borlase, a surgeon with a practice in Penzance. Davy's indenture is dated 10 February 1795. In the apothecary's dispensary, Davy became a chemist, conducted his earliest chemical experiments in a garret in Tonkin's house. Davy's friends said: "This boy Humphry is incorrigible, he will blow us all into the air." His elder sister complained of the ravages made on her dresses by corrosive substances. Davy was taught French by a refugee priest, in 1797 read Lavoisier's Traité élémentaire de chimie: much of his future work can be seen as reacting against Lavoisier's work and the dominance of French chemists.
As a poet, over one hundred and sixty manuscript poems were written by Davy, the majority of which are found in his personal notebooks. Most of his written poems were not published, he chose instead to share a few of them with his friends. Eight of his known poems were published, his poems reflected his views on both his career and his pereception of certain aspects of human life. He wrote on human endeavours and aspects of life like death, geology, natural theology and chemistry. John Ayrton Paris remarked that poetry written by the young Davy "bear the stamp of lofty genius". Davy's first preserved poem entitled The Sons of Genius is dated 1795 and marked by the usual immaturity of youth. Other poems written in the following years On the Mount's Bay and St Michael's Mount, are descriptive verses, showing sensibility but no true poetic imagination. Three of Davy's paintings from around 1796 have been donated to the Penlee House museum at Penzance. One is of the view from above Gulval showing the church, Mount's Bay and the Mount, while the other two depict Loch Lomond in Scotland.
While writing verses at the age of 17 in honour of his first love, he was eagerly discussing the question of the materiality of heat with his Quaker friend and mentor Robert Dunkin. Dunkin remarked:'I tell thee what, thou art the most quibbling hand at a dispute I met with in my life.' One winter day he took Davy to the Larigan River, To show him that rubbing two plates of ice together developed sufficient energy by motion, to melt them, that after the motion was suspended, the pieces were united by regelation. It was a crude form of analogous experiment exhibited by Davy in the lecture-room of the Royal Institution that elicited considerable attention; as professor at the Royal Institution, Davy repeated many of the ingenious experiments he learned from his friend and mentor, Robert Dunkin. Though he started writing his poems, albeit haphazardly, as a reflection of his views on his career and on life most of his final poems concentrated on immortality and death; this was after he started experiencing failing a decline both in health and career.
Davies Giddy met Davy in Penzance carelessly swinging on the half-gate of Dr Borlase's house, interested by his talk invited him to his house at Tredrea and offered him the use of his library. This led to an introduction to Dr Edwards. Edwards was a lecturer in
A light fixture, light fitting, or luminaire is an electrical device that contains an electric lamp that provides illumination. All light fixtures have one or more lamps; the lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place. Fixtures may have a switch to control the light, either attached to the lamp body or attached to the power cable. Permanent light fixtures, such as dining room chandeliers, may have no switch on the fixture itself, but rely on a wall switch. Fixtures require an electrical connection to a power source AC mains power, but some run on battery power for camping or emergency lights. Permanent lighting fixtures are directly wired. Movable lamps have a cord that plugs into a wall socket. Light fixtures may have other features, such as reflectors for directing the light, an aperture, an outer shell or housing for lamp alignment and protection, an electrical ballast or power supply, a shade to diffuse the light or direct it towards a workspace.
A wide variety of special light fixtures are created for use in the automotive lighting industry, aerospace and medicine sectors. Portable light fixtures are called lamps, as in table lamp or desk lamp. In technical terminology, the lamp is the light source, which, in casual terminology, is called the light bulb; the International Electrotechnical Commission recommends the term luminaire for technical use. Fixture manufacturing began soon after production of the incandescent light bulb; when practical uses of fluorescent lighting were realized after 1924, the three leading companies to produce various fixtures were Lightolier, Artcraft Fluorescent Lighting Corporation, Globe Lighting in the United States. Light fixtures are classified by how the fixture is installed, the light lamp type. Table lamp fixtures, standard lamp fixtures, office task light luminaires. Balanced-arm lamp is a spot light with an adjustable arm such as anglepoise or Luxo L1. Gooseneck lamp Nightlight Floor Lamp Torch lamp or torchières are floor lamps with an upward facing shade.
They provide general lighting to the rest of the room. Gooseneck lamp Bouillotte lamp: see Bouillotte Ceiling Dome – Also called the light source are hidden behind a translucent dome made of glass, with some combination of frosting and surface texturing to diffuse the light; these can be flush-mount fixtures mounted into the ceiling, or semi-flush fixtures separated by a small distance. Open ceiling dome – the translucent dome is suspended a short distance below the ceiling by a mechanism, hidden with the exception of a screw-knob or other device appearing on the outer dome face, pulling this knob releases the dome Enclosed ceiling dome The translucent dome mates with a ring, mounted flush with the ceiling Recessed light – the protective housing is concealed behind a ceiling or wall, leaving only the fixture itself exposed; the ceiling-mounted version is called a downlight. "Cans" with a variety of lamps – this term is jargon for inexpensive downlighting products that are recessed into the ceiling, or sometimes for uplights placed on the floor.
The name comes from the shape of the housing. The term "pot lights" is used in Canada and parts of the US. Cove light – recessed into the ceiling in a long box against a wall. Troffer – recessed fluorescent light fixtures rectangular in shape to fit into a drop ceiling grid. Surface-mounted light – the finished housing is exposed, not flush with surface Chandelier Pendant light – suspended from the ceiling with a chain or pipe Sconce – provide up or down lights. Track lighting fixture – individual fixtures can be positioned anywhere along the track, which provides electric power. Under-cabinet light – mounted below kitchen wall cabinets Display Case or Showcase light – shows merchandise on display within an enclosed case such as jewelry, grocery stores, chain stores. Ceiling fan – May sometimes have a light referred to as a light kit mounted to it. Emergency lighting or exit sign – connected to a battery backup or to an electric circuit that has emergency power if the mains power fails High- and low-bay lighting – used for general lighting for industrial buildings and big-box stores Strip lights or Industrial lighting – long lines of fluorescent lamps used in a warehouse or factory Outdoor lighting and landscape lighting – used to illuminate walkways, parking lots, building exteriors and architectural details and parks.
Outdoor light fixtures can include forms similar to indoor lighting, such as pendants, flush or close-to-ceiling light fixtures, wall-mounted lanterns and dome lights. High-mast pole – or stanchion-mounted – for landscape and parking lots Bollard – A type of architectural outdoor lighting, a short, upright ground-mounted unit used to provide cutoff type illumination for egress lighting, to light walkways, steps, or other pathways. Solar lamp Street light Yard light Accent light – Any directional light that highlights an object or attracts attention to a particular area Background light – for use in video production Blacklight Christmas lights – called fairy lights or twinkle lights and are used at Christmas and other holidays for decoration. Emergency light – provides minimal light to a building during a power outage. Exit sign Flood light Safelight Safety lamp Searchlight Security lighting Step light Strobe ligh
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed of fibroin and is produced by certain insect larvae to form cocoons; the best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity. The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colors. Silk is produced by several insects. There has been some research into other types of silk. Silk is produced by the larvae of insects undergoing complete metamorphosis, but some insects, such as webspinners and raspy crickets, produce silk throughout their lives. Silk production occurs in Hymenoptera, mayflies, leafhoppers, lacewings, fleas and midges. Other types of arthropods produce most notably various arachnids, such as spiders; the word silk comes from Old English: sioloc, from Ancient Greek: σηρικός, translit.
Sērikós, "silken" from an Asian source — compare Mandarin sī "silk", Manchurian sirghe, Mongolian sirkek. Several kinds of wild silk, which are produced by caterpillars other than the mulberry silkworm, have been known and used in China, South Asia, Europe since ancient times. However, the scale of production was always far smaller than for cultivated silks. There are several reasons for this: first, they differ from the domesticated varieties in colour and texture and are therefore less uniform. Thus, the only way to obtain silk suitable for spinning into textiles in areas where commercial silks are not cultivated was by tedious and labor-intensive carding. Commercial silks originate from reared silkworm pupae, which are bred to produce a white-colored silk thread with no mineral on the surface; the pupae are killed by either dipping them in boiling water before the adult moths emerge or by piercing them with a needle. These factors all contribute to the ability of the whole cocoon to be unravelled as one continuous thread, permitting a much stronger cloth to be woven from the silk.
Wild silks tend to be more difficult to dye than silk from the cultivated silkworm. A technique known as demineralizing allows the mineral layer around the cocoon of wild silk moths to be removed, leaving only variability in color as a barrier to creating a commercial silk industry based on wild silks in the parts of the world where wild silk moths thrive, such as in Africa and South America. Silk was first developed in ancient China; the earliest example of silk has been found in tombs at the neolithic site Jiahu in Henan, dates back 8,500 years. Silk fabric from 3630 BC was used as wrapping for the body of a child from a Yangshao culture site in Qingtaicun at Xingyang, Henan. Legend gives credit for developing silk to Leizu. Silks were reserved for the Emperors of China for their own use and gifts to others, but spread through Chinese culture and trade both geographically and and to many regions of Asia; because of its texture and lustre, silk became a popular luxury fabric in the many areas accessible to Chinese merchants.
Silk was in great demand, became a staple of pre-industrial international trade. In July 2007, archaeologists discovered intricately woven and dyed silk textiles in a tomb in Jiangxi province, dated to the Eastern Zhou Dynasty 2,500 years ago. Although historians have suspected a long history of a formative textile industry in ancient China, this find of silk textiles employing "complicated techniques" of weaving and dyeing provides direct evidence for silks dating before the Mawangdui-discovery and other silks dating to the Han Dynasty. Silk is described in a chapter of the Fan Shengzhi shu from the Western Han. There is a surviving calendar for silk production in an Eastern Han document; the two other known works on silk from the Han period are lost. The first evidence of the long distance silk trade is the finding of silk in the hair of an Egyptian mummy of the 21st dynasty, c.1070 BC. The silk trade reached as far as the Indian subcontinent, the Middle East and North Africa; this trade was so extensive that the major set of trade routes between Europe and Asia came to be known as the Silk Road.
The Emperors of China strove to keep knowledge of sericulture secret to maintain the Chinese monopoly. Nonetheless sericulture reached Korea with technological aid from China around 200 BC, the ancient Kingdom of Khotan by AD 50, India by AD 140. In the ancient era, silk from China was the most lucrative and sought-after luxury item traded across the Eurasian continent, many civilizations, such as the ancient Persians, benefited economically from trade. Chinese silk making process Silk has a long history in India, it is known as Resham in eastern and north India, Pattu in southern parts of India. Recent archaeological discoveries in Harappa and Chanhu-daro suggest that sericulture, employing wild silk threads from native silkworm species, existed in South Asia during the time of the Indus Valley Civilization dating between 2450 BC and 2000 BC, while "hard and fast evidence" for silk production in China dates back to around 2570 BC. Shelagh Vainker, a s