A street light, light pole, lamp pole, lamppost, streetlamp, light standard, or lamp standard is a raised source of light on the edge of a road or path. Similar lights may be found on a railway platform. When urban electric power distribution became ubiquitous in developed countries in the 20th century, lights for urban streets followed, or sometimes led. Many lamps have light-sensitive photocells or astro clocks that activate the lamp automatically when needed, at times when there is reduced ambient light compared to daytime, such as at dusk, dawn, or under exceptional cloud cover. This function in older lighting systems could be performed with the aid of a solar dial.
History
Preindustrial era Early lamps were used in the Ancient Greek and Ancient Roman civilizations, where light primarily served the purpose of security, to both protect the wanderer from tripping on the path over something and keep potential robbers at bay. At that time, oil lamps were used predominantly, as they provided a long-lasting and moderate flame. A slave responsible for lighting the oil lamps in front of Roman villas was called a lanternarius. In the words of Edwin Heathcote, "Romans illuminated the streets with oil lamps, and cities from Baghdad to Cordoba were similarly lit when most of Europe was living in what it is now rather unfashionable to call the Dark Ages but which were, from the point of view of street lighting, exactly that." So-called "link boys" escorted people from one place to another through the murky, winding streets of medieval towns. Before incandescent lamps, candle lighting was employed in cities. The earliest lamps required that a lamplighter tour the town at dusk, lighting each of the lamps. According to some sources, illumination was ordered in London in 1417 by Sir Henry Barton, Mayor of London, though there is no firm evidence of this.
Public street lighting was first developed in the 16th century, and accelerated following the invention of lanterns with glass windows by Edmund Heming in London and Jan van der Heyden in Amsterdam, which greatly improved the quantity of light. In 1588 the Parisian Parliament decreed that a torch be installed and lit at each intersection, and in 1594 the police changed this to lanterns. Still, in the mid 17th century it was a common practice for travellers to hire a lantern-bearer if they had to move at night through the dark, winding streets. King Louis XIV authorized sweeping reforms in Paris in 1667, which included the installation and maintenance of lights on streets and at intersections, as well as stiff penalties for vandalizing or stealing the fixtures. Paris had more than 2,700 streetlights by the end of the 17th century, and twice as many by 1730. Under this system, streets were lit with lanterns suspended 20 yards (18 m) apart on a cord over the middle of the street at a height of 20 feet (6.1 m); as an English visitor enthused in 1698, 'The streets are lit all winter and even during the full moon!' In London, public street lighting was implemented around the end of the 17th century; a diarist wrote in 1712 that 'All the way, quite through Hyde Park to the Queen's Palace at Kensington, lanterns were placed for illuminating the roads on dark nights.' A much-improved oil lantern, called a réverbère, was introduced in 1745 and improved in subsequent years. The light shed from these réverbères was considerably brighter, enough that some people complained of glare. These lamps were attached to the tops of lampposts; by 1817, there were 4,694 lamps on the Paris streets. During the French Revolution (1789–1799), the revolutionaries found that the lampposts were a convenient place to hang aristocrats and other opponents.
Gas lamp lighting
The first widespread system of street lighting used piped coal gas as fuel. Stephen Hales was the first person who procured a flammable fluid from the actual distillation of coal in 1726 and John Clayton, in 1735, called gas the "spirit" of coal and discovered its flammability by accident. William Murdoch (sometimes spelled "Murdock") was the first to use this gas for the practical application of lighting. In the early 1790s, while overseeing the use of his company's steam engines in tin mining in Cornwall, Murdoch began experimenting with various types of gas, finally settling on coal-gas as the most effective. He first lit his own house in Redruth, Cornwall in 1792. In 1798, he used gas to light the main building of the Soho Foundry and in 1802 lit the outside in a public display of gas lighting, the lights astonishing the local population.
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