title: Government of China

text: The CCP Politburo Standing Committee consists of the government's top leadership. Historically it has had five to nine members, and currently has seven members. Its officially mandated purpose is to conduct policy discussions and make decisions on major issues when the Politburo, a larger decision-making body, is not in session. According to the CCP's Constitution, the General Secretary of the Central Committee must also be a member of the CCP Politburo Standing Committee.


title: Government of China

text: The membership of the PSC is strictly ranked in protocol sequence. Historically, the general secretary (or party chairman) has been ranked first; the rankings of other leaders have varied over time. Since the 1990s, the general secretary (also the president), premier, chairman of the NPC Standing Committee, the chairman of the Chinese People's Political Consultative Conference, the secretary of the Central Commission for Discipline Inspection, the party's top anti-graft body, and the first-ranked secretary of the CCP secretariat have consistently also been members of the Politburo Standing Committee.


title: Government of China

text: Power is concentrated in the paramount leader, currently Xi Jinping, who heads the four most important political and state offices: He is the general secretary of the CCP Central Committee, Chairman of the Central Military Commission, and President of the PRC. Near the end of Hu Jintao's term in office, experts observed growing limitations to the Paramount leader's "de facto" control over the government, but at the 19th Party Congress in October 2017, Xi Jinping's term limits were removed and his powers were expanded considerably.


title: Government of China

text: The President of the People's Republic of China is the head of state. Under the PRC's constitution, the presidency is a largely ceremonial office with limited powers. However, since 1993, as a matter of convention, the presidency has been held simultaneously by the General Secretary of the Chinese Communist Party, the top leader in the one-party system. The office is officially regarded as an institution of the state rather than an administrative post; theoretically, the president serves at the pleasure of the National People's Congress, the legislature, and is not legally vested to take executive action on its own prerogative. The current president is Xi Jinping, who took office in March 2013.


title: Government of China

text: The office was first established in the Constitution of the People's Republic of China in 1954 and successively held by Mao Zedong and Liu Shaoqi. Liu fell into political disgrace during the Cultural Revolution, after which the office became vacant. The office was abolished under the Constitution of 1975, then reinstated in the Constitution of 1982, but with reduced powers. The official English-language translation of the title was "Chairman"; after 1982, this translation was changed to "President", although the Chinese title remains unchanged. In March 2018, presidential term limits were abolished.


title: Government of China

text: The State Council is the chief authority of the People's Republic of China. It is appointed by the National People's Congress and is chaired by the Premier of China and includes the heads of each governmental department and agency. There are about 50 members in the council. In the politics of the People's Republic of China, the Central People's Government forms one of three interlocking branches of power, the others being the Chinese Communist Party and the People's Liberation Army. The State Council directly oversees the various subordinate People's Governments in the provinces, and in practice maintains an interlocking membership with the top levels of the CCP.


title: Government of China

text: Currently the Premier of the State Council is Li Keqiang and the Vice Premiers are Han Zheng, Sun Chunlan, Hu Chunhua and Liu He. Together with the five State Councilors, they form the inner cabinet that regularly convenes for the State Council Executive Meeting.


title: Government of China

text: The Central Military Commission (CMC) exercises the command and control of the People's Liberation Army (PLA) and is supervised by the Standing Committee of the National People's Congress. It is nominally considered the supreme military policy-making body and its chairman, elected by the National People's Congress. Actual command and control of the PLA resides with the Central Military Commission of the CCP Central Committee.


title: Government of China

text: The commission is headed by the CMC Chairman, who is also the commander-in-chief of the national armed forces including the People's Liberation Army (PLA), the People's Armed Police (PAP), and the Militia.


title: Government of China

text: The National Supervisory Commission (NSC) is the highest supervisory (anti-corruption) agency of the PRC. At the same administrative ranking as the Supreme People's Court and Supreme People's Procuratorate, it supervises all public officials who exercise public power. Its operations are merged with the Central Commission for Discipline Inspection of the CCP. It replaces the former Ministry of Supervision.


title: Government of China

text: The Supreme People's Court is the judicial organ of the People's Republic of China. Hong Kong and Macau, as special administrative regions, have separate judicial systems based on British common law traditions and Portuguese civil-law traditions respectively, and are out of the jurisdiction of the Supreme People's Court. The judges of the Supreme People's Court are appointed by the National People's Congress.


title: Government of China

text: The governors of China's provinces and autonomous regions and mayors of its centrally controlled municipalities are appointed by the central government in Beijing after receiving the nominal consent of the National People's Congress (NPC). The Hong Kong and Macau special administrative regions (SARS) have some local autonomy since they have separate governments, legal systems, and basic constitutional laws, but they come under Beijing's control in matters of foreign policy and national security, and their chief executives are handpicked by the central government.


title: Government of China

text: Below the provincial level in 2004 there were 50 rural prefectures, 283 prefecture-level cities, 374 county-level cities, 852 county-level districts under the jurisdiction of nearby cities, and 1,636 counties. There also were 662 cities (including those incorporated into the four centrally controlled municipalities), 808 urban districts, and 43,258 township-level regions.


title: Government of China

text: Counties are divided into townships and villages. While most are run by appointed officials, some lower-level jurisdictions have direct popular elections. The organs of self-governing ethnic autonomous areas (regions, prefectures, and counties)—peoples' congresses and peoples' governments—exercise the same powers as their provincial-level counterparts but are guided additionally by the Law on Regional Ethnic Autonomy and require NPC Standing Committee approval for regulations they enact "in the exercise of autonomy" and "in light of the political, economic, and cultural characteristics of the ethnic group or ethnic groups in the areas."


title: Government of China

text: While operating under strict control and supervision by the central government, China's local governments manage relatively high share of fiscal revenues and expenditures.


title: Second Industrial Revolution

text: The Second Industrial Revolution, also known as the Technological Revolution, was a phase of rapid scientific discovery, standardization, mass production and industrialization from the late 19th century into the early 20th century. The First Industrial Revolution, which ended in the middle of the 19th century, was punctuated by a slowdown in important inventions before the Second Industrial Revolution in 1870. Though a number of its events can be traced to earlier innovations in manufacturing, such as the establishment of a machine tool industry, the development of methods for manufacturing interchangeable parts, as well as the invention of the Bessemer process to produce steel, the Second Industrial Revolution is generally dated between 1870 and 1914 (the beginning of World War I).


title: Second Industrial Revolution

text: Advancements in manufacturing and production technology enabled the widespread adoption of technological systems such as telegraph and railroad networks, gas and water supply, and sewage systems, which had earlier been concentrated to a few select cities. The enormous expansion of rail and telegraph lines after 1870 allowed unprecedented movement of people and ideas, which culminated in a new wave of globalization. In the same time period, new technological systems were introduced, most significantly electrical power and telephones. The Second Industrial Revolution continued into the 20th century with early factory electrification and the production line; it ended at the beginning of World War I.


title: Second Industrial Revolution

text: The Second Industrial Revolution was a period of rapid industrial development, primarily in the United Kingdom, Germany and the United States, but also in France, the Low Countries, Italy and Japan. It followed on from the First Industrial Revolution that began in Britain in the late 18th century that then spread throughout Western Europe. It came to an end with the start of the Second World War. While the First Revolution was driven by limited use of steam engines, interchangeable parts and mass production, and was largely water-powered (especially in the United States), the Second was characterized by the build-out of railroads, large-scale iron and steel production, widespread use of machinery in manufacturing, greatly increased use of steam power, widespread use of the telegraph, use of petroleum and the beginning of electrification. It also was the period during which modern organizational methods for operating large scale businesses over vast areas came into use.


title: Second Industrial Revolution

text: The concept was introduced by Patrick Geddes, "Cities in Evolution" (1910), and was being used by economists such as Erich Zimmermann (1951), but David Landes' use of the term in a 1966 essay and in "The Unbound Prometheus" (1972) standardized scholarly definitions of the term, which was most intensely promoted by Alfred Chandler (1918–2007). However, some continue to express reservations about its use.


title: Second Industrial Revolution

text: Landes (2003) stresses the importance of new technologies, especially, the internal combustion engine, petroleum, new materials and substances, including alloys and chemicals, electricity and communication technologies (such as the telegraph, telephone and radio).


title: Second Industrial Revolution

text: One author has called the period from 1867–1914 during which most of the great innovations were developed "The Age of Synergy" since the inventions and innovations were engineering and science-based.


title: Second Industrial Revolution

text: A synergy between iron and steel, railroads and coal developed at the beginning of the Second Industrial Revolution. Railroads allowed cheap transportation of materials and products, which in turn led to cheap rails to build more roads. Railroads also benefited from cheap coal for their steam locomotives. This synergy led to the laying of 75,000 miles of track in the U.S. in the 1880s, the largest amount anywhere in world history.


title: Second Industrial Revolution

text: The hot blast technique, in which the hot flue gas from a blast furnace is used to preheat combustion air blown into a blast furnace, was invented and patented by James Beaumont Neilson in 1828 at Wilsontown Ironworks in Scotland. Hot blast was the single most important advance in fuel efficiency of the blast furnace as it greatly reduced the fuel consumption for making pig iron, and was one of the most important technologies developed during the Industrial Revolution. Falling costs for producing wrought iron coincided with the emergence of the railway in the 1830s.


title: Second Industrial Revolution

text: The early technique of hot blast used iron for the regenerative heating medium. Iron caused problems with expansion and contraction, which stressed the iron and caused failure. Edward Alfred Cowper developed the Cowper stove in 1857. This stove used firebrick as a storage medium, solving the expansion and cracking problem. The Cowper stove was also capable of producing high heat, which resulted in very high throughput of blast furnaces. The Cowper stove is still used in today's blast furnaces.


title: Second Industrial Revolution

text: With the greatly reduced cost of producing pig iron with coke using hot blast, demand grew dramatically and so did the size of blast furnaces.


title: Second Industrial Revolution

text: The Bessemer process, invented by Sir Henry Bessemer, allowed the mass-production of steel, increasing the scale and speed of production of this vital material, and decreasing the labor requirements. The key principle was the removal of excess carbon and other impurities from pig iron by oxidation with air blown through the molten iron. The oxidation also raises the temperature of the iron mass and keeps it molten.


title: Second Industrial Revolution

text: The "acid" Bessemer process had a serious limitation in that it required relatively scarce hematite ore which is low in phosphorus. Sidney Gilchrist Thomas developed a more sophisticated process to eliminate the phosphorus from iron. Collaborating with his cousin, Percy Gilchrist a chemist at the Blaenavon Ironworks, Wales, he patented his process in 1878; Bolckow Vaughan & Co. in Yorkshire was the first company to use his patented process. His process was especially valuable on the continent of Europe, where the proportion of phosphoric iron was much greater than in England, and both in Belgium and in Germany the name of the inventor became more widely known than in his own country. In America, although non-phosphoric iron largely predominated, an immense interest was taken in the invention.


title: Second Industrial Revolution

text: The next great advance in steel making was the Siemens–Martin process. Sir Charles William Siemens developed his regenerative furnace in the 1850s, for which he claimed in 1857 to able to recover enough heat to save 70–80% of the fuel. The furnace operated at a high temperature by using regenerative preheating of fuel and air for combustion. Through this method, an open-hearth furnace can reach temperatures high enough to melt steel, but Siemens did not initially use it in that manner.


title: Second Industrial Revolution

text: French engineer Pierre-Émile Martin was the first to take out a license for the Siemens furnace and apply it to the production of steel in 1865. The Siemens–Martin process complemented rather than replaced the Bessemer process. Its main advantages were that it did not expose the steel to excessive nitrogen (which would cause the steel to become brittle), it was easier to control, and that it permitted the melting and refining of large amounts of scrap steel, lowering steel production costs and recycling an otherwise troublesome waste material. It became the leading steel making process by the early 20th century.


title: Second Industrial Revolution

text: The availability of cheap steel allowed building larger bridges, railroads, skyscrapers, and ships. Other important steel products—also made using the open hearth process—were steel cable, steel rod and sheet steel which enabled large, high-pressure boilers and high-tensile strength steel for machinery which enabled much more powerful engines, gears and axles than were previously possible. With large amounts of steel it became possible to build much more powerful guns and carriages, tanks, armored fighting vehicles and naval ships.


title: Second Industrial Revolution

text: The increase in steel production from the 1860s meant that railways could finally be made from steel at a competitive cost. Being a much more durable material, steel steadily replaced iron as the standard for railway rail, and due to its greater strength, longer lengths of rails could now be rolled. Wrought iron was soft and contained flaws caused by included dross. Iron rails could also not support heavy locomotives and were damaged by hammer blow. The first to make durable rails of steel rather than wrought iron was Robert Forester Mushet at the Darkhill Ironworks, Gloucestershire in 1857.


title: Second Industrial Revolution

text: The first of Mushet's steel rails was sent to Derby Midland railway station. The rails were laid at part of the station approach where the iron rails had to be renewed at least every six months, and occasionally every three. Six years later, in 1863, the rail seemed as perfect as ever, although some 700 trains had passed over it daily. This provided the basis for the accelerated construction of railways throughout the world in the late nineteenth century.


title: Second Industrial Revolution

text: The first commercially available steel rails in the US were manufactured in 1867 at the Cambria Iron Works in Johnstown, Pennsylvania.


title: Second Industrial Revolution

text: Steel rails lasted over ten times longer than did iron, and with the falling cost of steel, heavier weight rails were used. This allowed the use of more powerful locomotives, which could pull longer trains, and longer rail cars, all of which greatly increased the productivity of railroads. Rail became the dominant form of transport infrastructure throughout the industrialized world, producing a steady decrease in the cost of shipping seen for the rest of the century.


title: Second Industrial Revolution

text: The theoretical and practical basis for the harnessing of electric power was laid by the scientist and experimentalist Michael Faraday. Through his research on the magnetic field around a conductor carrying a direct current, Faraday established the basis for the concept of the electromagnetic field in physics. His inventions of electromagnetic rotary devices were the foundation of the practical use of electricity in technology.


title: Second Industrial Revolution

text: In 1881, Sir Joseph Swan, inventor of the first feasible incandescent light bulb, supplied about 1,200 Swan incandescent lamps to the Savoy Theatre in the City of Westminster, London, which was the first theatre, and the first public building in the world, to be lit entirely by electricity. Swan's lightbulb had already been used in 1879 to light Mosley Street, in Newcastle upon Tyne, the first electrical street lighting installation in the world. This set the stage for the electrification of industry and the home. The first large scale central distribution supply plant was opened at Holborn Viaduct in London in 1882 and later at Pearl Street Station in New York City.


title: Second Industrial Revolution

text: The first modern power station in the world was built by the English electrical engineer Sebastian de Ferranti at Deptford. Built on an unprecedented scale and pioneering the use of high voltage (10,000V) alternating current, it generated 800 kilowatts and supplied central London. On its completion in 1891 it supplied high-voltage AC power that was then "stepped down" with transformers for consumer use on each street. Electrification allowed the final major developments in manufacturing methods of the Second Industrial Revolution, namely the assembly line and mass production.


title: Second Industrial Revolution

text: Electrification was called "the most important engineering achievement of the 20th century" by the National Academy of Engineering. Electric lighting in factories greatly improved working conditions, eliminating the heat and pollution caused by gas lighting, and reducing the fire hazard to the extent that the cost of electricity for lighting was often offset by the reduction in fire insurance premiums. Frank J. Sprague developed the first successful DC motor in 1886. By 1889 110 electric street railways were either using his equipment or in planning. The electric street railway became a major infrastructure before 1920. The AC motor (Induction motor) was developed in the 1890s and soon began to be used in the electrification of industry. Household electrification did not become common until the 1920s, and then only in cities. Fluorescent lighting was commercially introduced at the 1939 World's Fair.


title: Second Industrial Revolution

text: Electrification also allowed the inexpensive production of electro-chemicals, such as aluminium, chlorine, sodium hydroxide, and magnesium.


title: Second Industrial Revolution

text: The use of machine tools began with the onset of the First Industrial Revolution. The increase in mechanization required more metal parts, which were usually made of cast iron or wrought iron—and hand working lacked precision and was a slow and expensive process. One of the first machine tools was John Wilkinson's boring machine, that bored a precise hole in James Watt's first steam engine in 1774. Advances in the accuracy of machine tools can be traced to Henry Maudslay and refined by Joseph Whitworth. Standardization of screw threads began with Henry Maudslay around 1800, when the modern screw-cutting lathe made interchangeable V-thread machine screws a practical commodity.


title: Second Industrial Revolution

text: In 1841, Joseph Whitworth created a design that, through its adoption by many British railway companies, became the world's first national machine tool standard called British Standard Whitworth. During the 1840s through 1860s, this standard was often used in the United States and Canada as well, in addition to myriad intra- and inter-company standards.


title: Second Industrial Revolution

text: The importance of machine tools to mass production is shown by the fact that production of the Ford Model T used 32,000 machine tools, most of which were powered by electricity. Henry Ford is quoted as saying that mass production would not have been possible without electricity because it allowed placement of machine tools and other equipment in the order of the work flow.


title: Second Industrial Revolution

text: The first paper making machine was the Fourdrinier machine, built by Sealy and Henry Fourdrinier, stationers in London. In 1800, Matthias Koops, working in London, investigated the idea of using wood to make paper, and began his printing business a year later. However, his enterprise was unsuccessful due to the prohibitive cost at the time.


title: Second Industrial Revolution

text: It was in the 1840s, that Charles Fenerty in Nova Scotia and Friedrich Gottlob Keller in Saxony both invented a successful machine which extracted the fibres from wood (as with rags) and from it, made paper. This started a new era for paper making, and, together with the invention of the fountain pen and the mass-produced pencil of the same period, and in conjunction with the advent of the steam driven rotary printing press, wood based paper caused a major transformation of the 19th century economy and society in industrialized countries. With the introduction of cheaper paper, schoolbooks, fiction, non-fiction, and newspapers became gradually available by 1900. Cheap wood based paper also allowed keeping personal diaries or writing letters and so, by 1850, the clerk, or writer, ceased to be a high-status job. By the 1880s chemical processes for paper manufacture were in use, becoming dominant by 1900.


title: Second Industrial Revolution

text: The petroleum industry, both production and refining, began in 1848 with the first oil works in Scotland. The chemist James Young set up a tiny business refining the crude oil in 1848. Young found that by slow distillation he could obtain a number of useful liquids from it, one of which he named "paraffine oil" because at low temperatures it congealed into a substance resembling paraffin wax. In 1850 Young built the first truly commercial oil-works and oil refinery in the world at Bathgate, using oil extracted from locally mined torbanite, shale, and bituminous coal to manufacture naphtha and lubricating oils; paraffin for fuel use and solid paraffin were not sold till 1856.


title: Second Industrial Revolution

text: Cable tool drilling was developed in ancient China and was used for drilling brine wells. The salt domes also held natural gas, which some wells produced and which was used for evaporation of the brine. Chinese well drilling technology was introduced to Europe in 1828.


title: Second Industrial Revolution

text: Although there were many efforts in the mid-19th century to drill for oil Edwin Drake's 1859 well near Titusville, Pennsylvania, is considered the first "modern oil well". Drake's well touched off a major boom in oil production in the United States. Drake learned of cable tool drilling from Chinese laborers in the U. S. The first primary product was kerosene for lamps and heaters. Similar developments around Baku fed the European market.


title: Second Industrial Revolution

text: Kerosene lighting was much more efficient and less expensive than vegetable oils, tallow and whale oil. Although town gas lighting was available in some cities, kerosene produced a brighter light until the invention of the gas mantle. Both were replaced by electricity for street lighting following the 1890s and for households during the 1920s. Gasoline was an unwanted byproduct of oil refining until automobiles were mass-produced after 1914, and gasoline shortages appeared during World War I. The invention of the Burton process for thermal cracking doubled the yield of gasoline, which helped alleviate the shortages.


title: Second Industrial Revolution

text: Synthetic dye was discovered by English chemist William Henry Perkin in 1856. At the time, chemistry was still in a quite primitive state; it was still a difficult proposition to determine the arrangement of the elements in compounds and chemical industry was still in its infancy. Perkin's accidental discovery was that aniline could be partly transformed into a crude mixture which when extracted with alcohol produced a substance with an intense purple colour. He scaled up production of the new "mauveine", and commercialized it as the world's first synthetic dye.


title: Second Industrial Revolution

text: After the discovery of mauveine, many new aniline dyes appeared (some discovered by Perkin himself), and factories producing them were constructed across Europe. Towards the end of the century, Perkin and other British companies found their research and development efforts increasingly eclipsed by the German chemical industry which became world dominant by 1914.


title: Second Industrial Revolution

text: The screw propeller was introduced in 1835 by Francis Pettit Smith who discovered a new way of building propellers by accident. Up to that time, propellers were literally screws, of considerable length. But during the testing of a boat propelled by one, the screw snapped off, leaving a fragment shaped much like a modern boat propeller. The boat moved faster with the broken propeller. The superiority of screw against paddles was taken up by navies. Trials with Smith's SS "Archimedes", the first steam driven screw, led to the famous tug-of-war competition in 1845 between the screw-driven and the paddle steamer ; the former pulling the latter backward at 2.5 knots (4.6 km/h).


title: Second Industrial Revolution

text: The first seagoing iron steamboat was built by Horseley Ironworks and named the "Aaron Manby". It also used an innovative oscillating engine for power. The boat was built at Tipton using temporary bolts, disassembled for transportation to London, and reassembled on the Thames in 1822, this time using permanent rivets.


title: Second Industrial Revolution

text: Other technological developments followed, including the invention of the surface condenser, which allowed boilers to run on purified water rather than salt water, eliminating the need to stop to clean them on long sea journeys. The "Great Western"


title: Second Industrial Revolution

text: , built by engineer Isambard Kingdom Brunel, was the longest ship in the world at with a keel and was the first to prove that transatlantic steamship services were viable. The ship was constructed mainly from wood, but Brunel added bolts and iron diagonal reinforcements to maintain the keel's strength. In addition to its steam-powered paddle wheels, the ship carried four masts for sails.


title: Second Industrial Revolution

text: Brunel followed this up with the "Great Britain", launched in 1843 and considered the first modern ship built of metal rather than wood, powered by an engine rather than wind or oars, and driven by propeller rather than paddle wheel. Brunel's vision and engineering innovations made the building of large-scale, propeller-driven, all-metal steamships a practical reality, but the prevailing economic and industrial conditions meant that it would be several decades before transoceanic steamship travel emerged as a viable industry.


title: Second Industrial Revolution

text: Highly efficient multiple expansion steam engines began being used on ships, allowing them to carry less coal than freight. The oscillating engine was first built by Aaron Manby and Joseph Maudslay in the 1820s as a type of direct-acting engine that was designed to achieve further reductions in engine size and weight. Oscillating engines had the piston rods connected directly to the crankshaft, dispensing with the need for connecting rods. To achieve this aim, the engine cylinders were not immobile as in most engines, but secured in the middle by trunnions which allowed the cylinders themselves to pivot back and forth as the crankshaft rotated, hence the term "oscillating".


title: Second Industrial Revolution

text: It was John Penn, engineer for the Royal Navy who perfected the oscillating engine. One of his earliest engines was the grasshopper beam engine. In 1844 he replaced the engines of the Admiralty yacht, with oscillating engines of double the power, without increasing either the weight or space occupied, an achievement which broke the naval supply dominance of Boulton & Watt and Maudslay, Son & Field. Penn also introduced the trunk engine for driving screw propellers in vessels of war. (1846) and (1848) were the first ships to be fitted with such engines and such was their efficacy that by the time of Penn's death in 1878, the engines had been fitted in 230 ships and were the first mass-produced, high-pressure and high-revolution marine engines.


title: Second Industrial Revolution

text: The revolution in naval design led to the first modern battleships in the 1870s, evolved from the ironclad design of the 1860s. The "Devastation"-class turret ships were built for the British Royal Navy as the first class of ocean-going capital ship that did not carry sails, and the first whose entire main armament was mounted on top of the hull rather than inside it.


title: Second Industrial Revolution

text: The vulcanization of rubber, by American Charles Goodyear and Englishman Thomas Hancock in the 1840s paved the way for a growing rubber industry, especially the manufacture of rubber tyres


title: Second Industrial Revolution

text: John Boyd Dunlop developed the first practical pneumatic tyre in 1887 in South Belfast. Willie Hume demonstrated the supremacy of Dunlop's newly invented pneumatic tyres in 1889, winning the tyre's first ever races in Ireland and then England.


title: Second Industrial Revolution

text: The modern bicycle was designed by the English engineer Harry John Lawson in 1876, although it was John Kemp Starley who produced the first commercially successful safety bicycle a few years later. Its popularity soon grew, causing the bike boom of the 1890s.


title: Second Industrial Revolution

text: Road networks improved greatly in the period, using the Macadam method pioneered by Scottish engineer John Loudon McAdam, and hard surfaced roads were built around the time of the bicycle craze of the 1890s. Modern tarmac was patented by British civil engineer Edgar Purnell Hooley in 1901.


title: Second Industrial Revolution

text: German inventor Karl Benz patented the world's first automobile in 1886. It featured wire wheels (unlike carriages' wooden ones) with a four-stroke engine of his own design between the rear wheels, with a very advanced coil ignition and evaporative cooling rather than a radiator. Power was transmitted by means of two roller chains to the rear axle. It was the first automobile entirely designed as such to generate its own power, not simply a motorized-stage coach or horse carriage.


title: Second Industrial Revolution

text: Benz began to sell the vehicle (advertising it as the Benz Patent Motorwagen) in the late summer of 1888, making it the first commercially available automobile in history.


title: Second Industrial Revolution

text: Henry Ford built his first car in 1896 and worked as a pioneer in the industry, with others who would eventually form their own companies, until the founding of Ford Motor Company in 1903. Ford and others at the company struggled with ways to scale up production in keeping with Henry Ford's vision of a car designed and manufactured on a scale so as to be affordable by the average worker. The solution that Ford Motor developed was a completely redesigned factory with machine tools and special purpose machines that were systematically positioned in the work sequence. All unnecessary human motions were eliminated by placing all work and tools within easy reach, and where practical on conveyors, forming the assembly line, the complete process being called mass production. This was the first time in history when a large, complex product consisting of 5000 parts had been produced on a scale of hundreds of thousands per year. The savings from mass production methods allowed the price of the Model T to decline from $780 in 1910 to $360 in 1916. In 1924 2 million T-Fords were produced and retailed $290 each.


title: Second Industrial Revolution

text: Applied science opened many opportunities. By the middle of the 19th century there was a scientific understanding of chemistry and a fundamental understanding of thermodynamics and by the last quarter of the century both of these sciences were near their present-day basic form. Thermodynamic principles were used in the development of physical chemistry. Understanding chemistry greatly aided the development of basic inorganic chemical manufacturing and the aniline dye industries.


title: Second Industrial Revolution

text: The science of metallurgy was advanced through the work of Henry Clifton Sorby and others. Sorby pioneered the study of iron and steel under microscope, which paved the way for a scientific understanding of metal and the mass-production of steel. In 1863 he used etching with acid to study the microscopic structure of metals and was the first to understand that a small but precise quantity of carbon gave steel its strength. This paved the way for Henry Bessemer and Robert Forester Mushet to develop the method for mass-producing steel.


title: Second Industrial Revolution

text: Other processes were developed for purifying various elements such as chromium, molybdenum, titanium, vanadium and nickel which could be used for making alloys with special properties, especially with steel. Vanadium steel, for example, is strong and fatigue resistant, and was used in half the automotive steel. Alloy steels were used for ball bearings which were used in large scale bicycle production in the 1880s. Ball and roller bearings also began being used in machinery. Other important alloys are used in high temperatures, such as steam turbine blades, and stainless steels for corrosion resistance.


title: Second Industrial Revolution

text: The work of Justus von Liebig and August Wilhelm von Hofmann laid the groundwork for modern industrial chemistry. Liebig is considered the "father of the fertilizer industry" for his discovery of nitrogen as an essential plant nutrient and went on to establish Liebig's Extract of Meat Company which produced the Oxo meat extract. Hofmann headed a school of practical chemistry in London, under the style of the Royal College of Chemistry, introduced modern conventions for molecular modeling and taught Perkin who discovered the first synthetic dye.


title: Second Industrial Revolution

text: The science of thermodynamics was developed into its modern form by Sadi Carnot, William Rankine, Rudolf Clausius, William Thomson, James Clerk Maxwell, Ludwig Boltzmann and J. Willard Gibbs. These scientific principles were applied to a variety of industrial concerns, including improving the efficiency of boilers and steam turbines. The work of Michael Faraday and others was pivotal in laying the foundations of the modern scientific understanding of electricity.


title: Second Industrial Revolution

text: Scottish scientist James Clerk Maxwell was particularly influential—his discoveries ushered in the era of modern physics. His most prominent achievement was to formulate a set of equations that described electricity, magnetism, and optics as manifestations of the same phenomenon, namely the electromagnetic field. The unification of light and electrical phenomena led to the prediction of the existence of radio waves and was the basis for the future development of radio technology by Hughes, Marconi and others.


title: Second Industrial Revolution

text: Maxwell himself developed the first durable colour photograph in 1861 and published the first scientific treatment of control theory. Control theory is the basis for process control, which is widely used in automation, particularly for process industries, and for controlling ships and airplanes. Control theory was developed to analyze the functioning of centrifugal governors on steam engines. These governors came into use in the late 18th century on wind and water mills to correctly position the gap between mill stones, and were adapted to steam engines by James Watt. Improved versions were used to stabilize automatic tracking mechanisms of telescopes and to control speed of ship propellers and rudders. However, those governors were sluggish and oscillated about the set point. James Clerk Maxwell wrote a paper mathematically analyzing the actions of governors, which marked the beginning of the formal development of control theory. The science was continually improved and evolved into an engineering discipline.


title: Second Industrial Revolution

text: Justus von Liebig was the first to understand the importance of ammonia as fertilizer, and promoted the importance of inorganic minerals to plant nutrition. In England, he attempted to implement his theories commercially through a fertilizer created by treating phosphate of lime in bone meal with sulfuric acid. Another pioneer was John Bennet Lawes who began to experiment on the effects of various manures on plants growing in pots in 1837, leading to a manure formed by treating phosphates with sulphuric acid; this was to be the first product of the nascent artificial manure industry.


title: Second Industrial Revolution

text: The discovery of coprolites in commercial quantities in East Anglia, led Fisons and Edward Packard to develop one of the first large-scale commercial fertilizer plants at Bramford, and Snape in the 1850s. By the 1870s superphosphates produced in those factories, were being shipped around the world from the port at Ipswich.


title: Second Industrial Revolution

text: The Birkeland–Eyde process was developed by Norwegian industrialist and scientist Kristian Birkeland along with his business partner Sam Eyde in 1903, but was soon replaced by the much more efficient Haber process,


title: Second Industrial Revolution

text: developed by the Nobel prize-winning chemists Carl Bosch of IG Farben and Fritz Haber in Germany. The process used molecular nitrogen (N) and methane (CH) gas in an economically sustainable synthesis of ammonia (NH). The ammonia produced in the Haber process is the main raw material for production of nitric acid.


title: Second Industrial Revolution

text: The steam turbine was developed by Sir Charles Parsons in 1884. His first model was connected to a dynamo that generated 7.5 kW (10 hp) of electricity. The invention of Parson's steam turbine made cheap and plentiful electricity possible and revolutionized marine transport and naval warfare. By the time of Parson's death, his turbine had been adopted for all major world power stations. Unlike earlier steam engines, the turbine produced rotary power rather than reciprocating power which required a crank and heavy flywheel. The large number of stages of the turbine allowed for high efficiency and reduced size by 90%. The turbine's first application was in shipping followed by electric generation in 1903.


title: Second Industrial Revolution

text: The first widely used internal combustion engine was the Otto type of 1876. From the 1880s until electrification it was successful in small shops because small steam engines were inefficient and required too much operator attention. The Otto engine soon began being used to power automobiles, and remains as today's common gasoline engine.


title: Second Industrial Revolution

text: The diesel engine was independently designed by Rudolf Diesel and Herbert Akroyd Stuart in the 1890s using thermodynamic principles with the specific intention of being highly efficient. It took several years to perfect and become popular, but found application in shipping before powering locomotives. It remains the world's most efficient prime mover.


title: Second Industrial Revolution

text: The first commercial telegraph system was installed by Sir William Fothergill Cooke and Charles Wheatstone in May 1837 between Euston railway station and Camden Town in London.


title: Second Industrial Revolution

text: The rapid expansion of telegraph networks took place throughout the century, with the first undersea telegraph cable being built by John Watkins Brett between France and England.


title: Second Industrial Revolution

text: The Atlantic Telegraph Company was formed in London in 1856 to undertake construction of a commercial telegraph cable across the Atlantic Ocean. This was successfully completed on 18 July 1866 by the ship SS "Great Eastern", captained by Sir James Anderson after many mishaps along the away. From the 1850s until 1911, British submarine cable systems dominated the world system. This was set out as a formal strategic goal, which became known as the All Red Line.


title: Second Industrial Revolution

text: The telephone was patented in 1876 by Alexander Graham Bell, and like the early telegraph, it was used mainly to speed business transactions.


title: Second Industrial Revolution

text: As mentioned above, one of the most important scientific advancements in all of history was the unification of light, electricity and magnetism through Maxwell's electromagnetic theory. A scientific understanding of electricity was necessary for the development of efficient electric generators, motors and transformers. David Edward Hughes and Heinrich Hertz both demonstrated and confirmed the phenomenon of electromagnetic waves that had been predicted by Maxwell.


title: Second Industrial Revolution

text: It was Italian inventor Guglielmo Marconi who successfully commercialized radio at the turn of the century. He founded The Wireless Telegraph & Signal Company in Britain in 1897 and in the same year transmitted Morse code across Salisbury Plain, sent the first ever wireless communication over open sea and made the first transatlantic transmission in 1901 from Poldhu, Cornwall to Signal Hill, Newfoundland. Marconi built high-powered stations on both sides of the Atlantic and began a commercial service to transmit nightly news summaries to subscribing ships in 1904.


title: Second Industrial Revolution

text: The key development of the vacuum tube by Sir John Ambrose Fleming in 1904 underpinned the development of modern electronics and radio broadcasting. Lee De Forest's subsequent invention of the triode allowed the amplification of electronic signals, which paved the way for radio broadcasting in the 1920s.


title: Second Industrial Revolution

text: Railroads are credited with creating the modern business enterprise by scholars such as Alfred Chandler. Previously, the management of most businesses had consisted of individual owners or groups of partners, some of whom often had little daily hands-on operations involvement. Centralized expertise in the home office was not enough. A railroad required expertise available across the whole length of its trackage, to deal with daily crises, breakdowns and bad weather. A collision in Massachusetts in 1841 led to a call for safety reform. This led to the reorganization of railroads into different departments with clear lines of management authority. When the telegraph became available, companies built telegraph lines along the railroads to keep track of trains.


title: Second Industrial Revolution

text: Railroads involved complex operations and employed extremely large amounts of capital and ran a more complicated business compared to anything previous. Consequently, they needed better ways to track costs. For example, to calculate rates they needed to know the cost of a ton-mile of freight. They also needed to keep track of cars, which could go missing for months at a time. This led to what was called "railroad accounting", which was later adopted by steel and other industries, and eventually became modern accounting.


title: Second Industrial Revolution

text: Later in the Second Industrial Revolution, Frederick Winslow Taylor and others in America developed the concept of scientific management or Taylorism. Scientific management initially concentrated on reducing the steps taken in performing work (such as bricklaying or shoveling) by using analysis such as time-and-motion studies, but the concepts evolved into fields such as industrial engineering, manufacturing engineering, and business management that helped to completely restructure the operations of factories, and later entire segments of the economy.


title: Second Industrial Revolution

text: The period from 1870 to 1890 saw the greatest increase in economic growth in such a short period as ever in previous history. Living standards improved significantly in the newly industrialized countries as the prices of goods fell dramatically due to the increases in productivity. This caused unemployment and great upheavals in commerce and industry, with many laborers being displaced by machines and many factories, ships and other forms of fixed capital becoming obsolete in a very short time span.


title: Second Industrial Revolution

text: "The economic changes that have occurred during the last quarter of a century -or during the present generation of living men- have unquestionably been more important and more varied than during any period of the world's history".


title: Second Industrial Revolution

text: Crop failures no longer resulted in starvation in areas connected to large markets through transport infrastructure.


title: Second Industrial Revolution

text: Massive improvements in public health and sanitation resulted from public health initiatives, such as the construction of the London sewerage system in the 1860s and the passage of laws that regulated filtered water supplies—(the Metropolis Water Act introduced regulation of the water supply companies in London, including minimum standards of water quality for the first time in 1852). This greatly reduced the infection and death rates from many diseases.


title: Second Industrial Revolution

text: By 1870 the work done by steam engines exceeded that done by animal and human power. Horses and mules remained important in agriculture until the development of the internal combustion tractor near the end of the Second Industrial Revolution.


title: Second Industrial Revolution

text: Improvements in steam efficiency, like triple-expansion steam engines, allowed ships to carry much more freight than coal, resulting in greatly increased volumes of international trade. Higher steam engine efficiency caused the number of steam engines to increase several fold, leading to an increase in coal usage, the phenomenon being called the Jevons paradox.


title: Second Industrial Revolution

text: By 1890 there was an international telegraph network allowing orders to be placed by merchants in England or the US to suppliers in India and China for goods to be transported in efficient new steamships. This, plus the opening of the Suez Canal, led to the decline of the great warehousing districts in London and elsewhere, and the elimination of many middlemen.


title: Second Industrial Revolution

text: The tremendous growth in productivity, transportation networks, industrial production and agricultural output lowered the prices of almost all goods. This led to many business failures and periods that were called "depressions" that occurred as the world economy actually grew. See also: Long depression


title: Second Industrial Revolution

text: The factory system centralized production in separate buildings funded and directed by specialists (as opposed to work at home). The division of labor made both unskilled and skilled labor more productive, and led to a rapid growth of population in industrial centers. The shift away from agriculture toward industry had occurred in Britain by the 1730s, when the percentage of the working population engaged in agriculture fell below 50%, a development that would only happen elsewhere (the Low Countries) in the 1830s and '40s. By 1890, the figure had fallen to under 10% and the vast majority of the British population was urbanized. This milestone was reached by the Low Countries and the US in the 1950s.


title: Second Industrial Revolution

text: Like the first industrial revolution, the second supported population growth and saw most governments protect their national economies with tariffs. Britain retained its belief in free trade throughout this period. The wide-ranging social impact of both revolutions included the remaking of the working class as new technologies appeared. The changes resulted in the creation of a larger, increasingly professional, middle class, the decline of child labor and the dramatic growth of a consumer-based, material culture.


title: Second Industrial Revolution

text: By 1900, the leaders in industrial production was Britain with 24% of the world total, followed by the US (19%), Germany (13%), Russia (9%) and France (7%). Europe together accounted for 62%.


title: Second Industrial Revolution

text: The great inventions and innovations of the Second Industrial Revolution are part of our modern life. They continued to be drivers of the economy until after WWII. Major innovations occurred in the post-war era, some of which are: computers, semiconductors, the fiber optic network and the Internet, cellular telephones, combustion turbines (jet engines) and the Green Revolution. Although commercial aviation existed before WWII, it became a major industry after the war.


title: Second Industrial Revolution

text: New products and services were introduced which greatly increased international trade. Improvements in steam engine design and the wide availability of cheap steel meant that slow, sailing ships were replaced with faster steamship, which could handle more trade with smaller crews. The chemical industries also moved to the forefront. Britain invested less in technological research than the U.S. and Germany, which caught up.


title: Second Industrial Revolution

text: The development of more intricate and efficient machines along with mass production techniques (after 1910) greatly expanded output and lowered production costs. As a result, production often exceeded domestic demand. Among the new conditions, more markedly evident in Britain, the forerunner of Europe's industrial states, were the long-term effects of the severe Long Depression of 1873–1896, which had followed fifteen years of great economic instability. Businesses in practically every industry suffered from lengthy periods of low – and falling – profit rates and price deflation after 1873.


title: Second Industrial Revolution

text: The U.S had its highest economic growth rate in the last two decades of the Second Industrial Revolution; however, population growth slowed while productivity growth peaked around the mid 20th century. The Gilded Age in America was based on heavy industry such as factories, railroads and coal mining. The iconic event was the opening of the First transcontinental railroad in 1869, providing six-day service between the East Coast and San Francisco.


title: Second Industrial Revolution

text: During the Gilded Age, American railroad mileage tripled between 1860 and 1880, and tripled again by 1920, opening new areas to commercial farming, creating a truly national marketplace and inspiring a boom in coal mining and steel production. The voracious appetite for capital of the great trunk railroads facilitated the consolidation of the nation's financial market in Wall Street. By 1900, the process of economic concentration had extended into most branches of industry—a few large corporations, some organized as "trusts" (e.g. Standard Oil), dominated in steel, oil, sugar, meatpacking, and the manufacture of agriculture machinery. Other major components of this infrastructure were the new methods for manufacturing steel, especially the Bessemer process. The first billion-dollar corporation was United States Steel, formed by financier J. P. Morgan in 1901, who purchased and consolidated steel firms built by Andrew Carnegie and others.


title: Second Industrial Revolution

text: Increased mechanization of industry and improvements to worker efficiency, increased the productivity of factories while undercutting the need for skilled labor. Mechanical innovations such as batch and continuous processing began to become much more prominent in factories. This mechanization made some factories an assemblage of unskilled laborers performing simple and repetitive tasks under the direction of skilled foremen and engineers. In some cases, the advancement of such mechanization substituted for low-skilled workers altogether. Both the number of unskilled and skilled workers increased, as their wage rates grew Engineering colleges were established to feed the enormous demand for expertise. Together with rapid growth of small business, a new middle class was rapidly growing, especially in northern cities.


title: Second Industrial Revolution

text: In the early 1900s there was a disparity between the levels of employment seen in the northern and southern United States. On average, states in the North had both a higher population, and a higher rate of employment than states in the South. The higher rate of employment is easily seen by considering the 1909 rates of employment compared to the populations of each state in the 1910 census. This difference was most notable in the states with the largest populations, such as New York and Pennsylvania. Each of these states had roughly 5 percent more of the total US workforce than would be expected given their populations. Conversely, the states in the South with the best actual rates of employment, North Carolina and Georgia, had roughly 2 percent less of the workforce than one would expect from their population. When the averages of all southern states and all northern states are taken, the trend holds with the North over-performing by about 2 percent, and the South under-performing by about 1 percent.


title: Second Industrial Revolution

text: The German Empire came to rival Britain as Europe's primary industrial nation during this period. Since Germany industrialized later, it was able to model its factories after those of Britain, thus making more efficient use of its capital and avoiding legacy methods in its leap to the envelope of technology. Germany invested more heavily than the British in research, especially in chemistry, motors and electricity. The German concern system (known as "Konzerne"), being significantly concentrated, was able to make more efficient use of capital. Germany was not weighted down with an expensive worldwide empire that needed defense. Following Germany's annexation of Alsace-Lorraine in 1871, it absorbed parts of what had been France's industrial base.


title: Second Industrial Revolution

text: By 1900 the German chemical industry dominated the world market for synthetic dyes. The three major firms BASF, Bayer and Hoechst produced several hundred different dyes, along with the five smaller firms. In 1913 these eight firms produced almost 90 percent of the world supply of dyestuffs, and sold about 80 percent of their production abroad. The three major firms had also integrated upstream into the production of essential raw materials and they began to expand into other areas of chemistry such as pharmaceuticals, photographic film, agricultural chemicals and electrochemical. Top-level decision-making was in the hands of professional salaried managers, leading Chandler to call the German dye companies "the world's first truly managerial industrial enterprises". There were many spin offs from research—such as the pharmaceutical industry, which emerged from chemical research.


title: Second Industrial Revolution

text: Belgium during the Belle Époque showed the value of the railways for speeding the Second Industrial Revolution. After 1830, when it broke away from the Netherlands and became a new nation, it decided to stimulate industry. It planned and funded a simple cruciform system that connected major cities, ports and mining areas, and linked to neighboring countries. Belgium thus became the railway center of the region. The system was soundly built along British lines, so that profits were low but the infrastructure necessary for rapid industrial growth was put in place.


title: Second Industrial Revolution

text: There have been other times that have been called "second industrial revolution". Industrial revolutions may be renumbered by taking earlier developments, such as the rise of medieval technology in the 12th century, or of ancient Chinese technology during the Tang dynasty, or of ancient Roman technology, as first. "Second industrial revolution" has been used in the popular press and by technologists or industrialists to refer to the changes following the spread of new technology after World War I.


title: Second Industrial Revolution

text: Excitement and debate over the dangers and benefits of the Atomic Age were more intense and lasting than those over the Space age but both were predicted to lead to another industrial revolution. At the start of the 21st century the term "second industrial revolution" has been used to describe the anticipated effects of hypothetical molecular nanotechnology systems upon society. In this more recent scenario, they would render the majority of today's modern manufacturing processes obsolete, transforming all facets of the modern economy. Subsequent industrial revolutions include the Digital revolution and Environmental revolution.


title: Brushless DC electric motor

text: A brushless DC electric motor (BLDC motor or BL motor), also known as an electronically commutated motor (ECM or EC motor) or synchronous DC motor, is a synchronous motor using a direct current (DC) electric power supply. It uses an electronic controller to switch DC currents to the motor windings producing magnetic fields which effectively rotate in space and which the permanent magnet rotor follows. The controller adjusts the phase and amplitude of the DC current pulses to control the speed and torque of the motor. This control system is an alternative to the mechanical commutator (brushes) used in many conventional electric motors.


title: Brushless DC electric motor

text: The construction of a brushless motor system is typically similar to a permanent magnet synchronous motor (PMSM), but can also be a switched reluctance motor, or an induction (asynchronous) motor. They may also use neodymium magnets and be outrunners (the stator is surrounded by the rotor), inrunners (the rotor is surrounded by the stator), or axial (the rotor and stator are flat and parallel).


title: Brushless DC electric motor

text: The advantages of a brushless motor over brushed motors are high power-to-weight ratio, high speed, nearly instantaneous control of speed (rpm) and torque, high efficiency, and low maintenance. Brushless motors find applications in such places as computer peripherals (disk drives, printers), hand-held power tools, and vehicles ranging from model aircraft to automobiles. In modern washing machines, brushless DC motors have allowed replacement of rubber belts and gearboxes by a direct-drive design.


title: Brushless DC electric motor

text: Brushed DC motors were invented in the 19th century and are still common. Brushless DC motors were made possible by the development of solid state electronics in the 1960s.


title: Brushless DC electric motor

text: An electric motor develops torque by keeping the magnetic fields of the rotor (the rotating part of the machine) and the stator (the fixed part of the machine) misaligned. One or both sets of magnets are electromagnets, made of a coil of wire wound around an iron core. DC running through the wire winding creates the magnetic field, providing the power which runs the motor. The misalignment generates a torque that tries to realign the fields. As the rotor moves, and the fields come into alignment, it is necessary to move either the rotor's or stator's field to maintain the misalignment and continue to generate torque and movement. The device that moves the fields based on the position of the rotor is called a commutator.


title: Brushless DC electric motor

text: In brushed motors this is done with a rotary switch on the motor's shaft called a commutator. It consists of a rotating cylinder or disc divided into multiple metal contact segments on the rotor. The segments are connected to conductor windings on the rotor. Two or more stationary contacts called "brushes", made of a soft conductor such as graphite, press against the commutator, making sliding electrical contact with successive segments as the rotor turns. The brushes selectively provide electric current to the windings. As the rotor rotates, the commutator selects different windings and the directional current is applied to a given winding such that the rotor's magnetic field remains misaligned with the stator and creates a torque in one direction.


title: Brushless DC electric motor

text: The commutator has disadvantages that has led to a decline in use of brushed motors. These disadvantages are:


title: Brushless DC electric motor

text: During the last hundred years, high-power DC brushed motors, once the mainstay of industry, were replaced by alternating current (AC) synchronous motors. Today, brushed motors are used only in low power applications or where only DC is available, but the above drawbacks limit their use even in these applications.


title: Brushless DC electric motor

text: In brushless DC motors, an electronic servo system replaces the mechanical commutator contacts. An electronic sensor detects the angle of the rotor and controls semiconductor switches such as transistors which switch current through the windings, either reversing the direction of the current or, in some motors turning it off, at the correct angle so the electromagnets create torque in one direction. The elimination of the sliding contact allows brushless motors to have less friction and longer life; their working life is only limited by the lifetime of their bearings.


title: Brushless DC electric motor

text: Brushed DC motors develop a maximum torque when stationary, linearly decreasing as velocity increases. Some limitations of brushed motors can be overcome by brushless motors; they include higher efficiency and lower susceptibility to mechanical wear. These benefits come at the cost of potentially less rugged, more complex, and more expensive control electronics.


title: Brushless DC electric motor

text: A typical brushless motor has permanent magnets that rotate around a fixed armature, eliminating problems associated with connecting current to the moving armature. An electronic controller replaces the commutator assembly of the brushed DC motor, which continually switches the phase to the windings to keep the motor turning. The controller performs similar timed power distribution by using a solid-state circuit rather than the commutator system.


title: Brushless DC electric motor

text: Brushless motors offer several advantages over brushed DC motors, including high torque to weight ratio, increased efficiency producing more torque per watt, increased reliability, reduced noise, longer lifetime by eliminating brush and commutator erosion, elimination of ionizing sparks from the commutator, and an overall reduction of electromagnetic interference (EMI). With no windings on the rotor, they are not subjected to centrifugal forces, and because the windings are supported by the housing, they can be cooled by conduction, requiring no airflow inside the motor for cooling. This in turn means that the motor's internals can be entirely enclosed and protected from dirt or other foreign matter.


title: Brushless DC electric motor

text: Brushless motor commutation can be implemented in software using a microcontroller, or may alternatively be implemented using analog or digital circuits. Commutation with electronics instead of brushes allows for greater flexibility and capabilities not available with brushed DC motors, including speed limiting, microstepping operation for slow and fine motion control, and a holding torque when stationary. Controller software can be customized to the specific motor being used in the application, resulting in greater commutation efficiency.


title: Brushless DC electric motor

text: The maximum power that can be applied to a brushless motor is limited almost exclusively by heat; too much heat weakens the magnets and will damage the windings' insulation.


title: Brushless DC electric motor

text: When converting electricity into mechanical power, brushless motors are more efficient than brushed motors primarily due to the absence of brushes, which reduces mechanical energy loss due to friction. The enhanced efficiency is greatest in the no-load and low-load regions of the motor's performance curve.


title: Brushless DC electric motor

text: Environments and requirements in which manufacturers use brushless-type DC motors include maintenance-free operation, high speeds, and operation where sparking is hazardous (i.e. explosive environments) or could affect electronically sensitive equipment.


title: Brushless DC electric motor

text: The construction of a brushless motor resembles a stepper motor, but the motors have important differences due to differences in implementation and operation. While stepper motors are frequently stopped with the rotor in a defined angular position, a brushless motor is usually intended to produce continuous rotation. Both motor types may have a rotor position sensor for internal feedback. Both a stepper motor and a well-designed brushless motor can hold finite torque at zero RPM.


title: Brushless DC electric motor

text: Because the controller implements the traditional brushes' functionality it needs to know the rotor's orientation relative to the stator coils. This is automatic in a brushed motor due to the fixed geometry of the rotor shaft and brushes. Some designs use Hall effect sensors or a rotary encoder to directly measure the rotor's position. Others measure the back-EMF in the undriven coils to infer the rotor position, eliminating the need for separate Hall effect sensors. These are therefore often called "sensorless" controllers.


title: Brushless DC electric motor

text: Controllers that sense rotor position based on back-EMF have extra challenges in initiating motion because no back-EMF is produced when the rotor is stationary. This is usually accomplished by beginning rotation from an arbitrary phase, and then skipping to the correct phase if it is found to be wrong. This can cause the motor to run backwards briefly, adding even more complexity to the startup sequence. Other sensorless controllers are capable of measuring winding saturation caused by the position of the magnets to infer the rotor position.


title: Brushless DC electric motor

text: A typical controller contains three polarity-reversible outputs controlled by a logic circuit. Simple controllers employ comparators working from the orientation sensors to determine when the output phase should be advanced. More advanced controllers employ a microcontroller to manage acceleration, control motor speed and fine-tune efficiency.


title: Brushless DC electric motor

text: Two key performance parameters of brushless DC motors are the motor constants formula_1 (torque constant) and formula_2 (back-EMF constant, also known as speed constant formula_3).


title: Brushless DC electric motor

text: Brushless motors can be constructed in several different physical configurations. In the conventional inrunner configuration, the permanent magnets are part of the rotor. Three stator windings surround the rotor. In the external-rotor outrunner configuration, the radial relationship between the coils and magnets is reversed; the stator coils form the center (core) of the motor, while the permanent magnets spin within an overhanging rotor that surrounds the core. Outrunners typically have more poles, set up in triplets to maintain the three groups of windings, and have a higher torque at low RPMs. In the flat axial flux type, used where there are space or shape constraints, stator and rotor plates are mounted face to face. In all brushless motors, the coils are stationary.


title: Brushless DC electric motor

text: There are two common electrical winding configurations; the delta configuration connects three windings to each other in a triangle-like circuit, and power is applied at each of the connections. The wye ("Y"-shaped) configuration, sometimes called a star winding, connects all of the windings to a central point, and power is applied to the remaining end of each winding. A motor with windings in delta configuration gives low torque at low speed but can give higher top speed. Wye configuration gives high torque at low speed, but not as high top speed. The wye winding is normally more efficient. Delta-connected windings can allow high-frequency parasitic electrical currents to circulate entirely within the motor. A Wye-connected winding does not contain a closed loop in which parasitic currents can flow, preventing such losses. Aside from the higher impedance of the wye configuration, from a controller standpoint, the two winding configurations can be treated exactly the same.


title: Brushless DC electric motor

text: Brushless motors fulfill many functions originally performed by brushed DC motors, but cost and control complexity prevents brushless motors from replacing brushed motors completely in the lowest-cost areas. Nevertheless, brushless motors have come to dominate many applications, particularly devices such as computer hard drives and CD/DVD players. Small cooling fans in electronic equipment are powered exclusively by brushless motors. They can be found in cordless power tools where the increased efficiency of the motor leads to longer periods of use before the battery needs to be charged. Low speed, low power brushless motors are used in direct-drive turntables for gramophone records.


title: Brushless DC electric motor

text: Brushless motors are found in electric vehicles, hybrid vehicles, personal transporters, and electric aircraft. Most electric bicycles use brushless motors that are sometimes built into the wheel hub itself, with the stator fixed solidly to the axle and the magnets attached to and rotating with the wheel. The same principle is applied in self-balancing scooter wheels. Most electrically powered radio-controlled models use brushless motors because of their high efficiency.


title: Brushless DC electric motor

text: Brushless motors are found in many modern cordless tools, including some string trimmers, leaf blowers, saws (circular and reciprocating), and drills/drivers. The weight and efficiency advantages of brushless over brushed motors are more important to handheld, battery-powered tools than to large, stationary tools plugged into an AC outlet.


title: Brushless DC electric motor

text: There is a trend in the heating, ventilation, and air conditioning (HVAC) and refrigeration industries to use brushless motors instead of various types of AC motors. The most significant reason to switch to a brushless motor is a reduction in power required to operate them versus a typical AC motor. In addition to the brushless motor's higher efficiency, HVAC systems, especially those featuring variable-speed or load modulation, use brushless motors to give the built-in microprocessor continuous control over cooling and airflow.


title: Brushless DC electric motor

text: The application of brushless DC motors within industrial engineering primarily focuses on manufacturing engineering or industrial automation design. Brushless motors are ideally suited for manufacturing applications because of their high power density, good speed-torque characteristics, high efficiency, wide speed ranges and low maintenance. The most common uses of brushless DC motors in industrial engineering are motion control, linear actuators, servomotors, actuators for industrial robots, extruder drive motors and feed drives for CNC machine tools.


title: Brushless DC electric motor

text: Brushless motors are commonly used as pump, fan and spindle drives in adjustable or variable speed applications as they are capable of developing high torque with good speed response. In addition, they can be easily automated for remote control. Due to their construction, they have good thermal characteristics and high energy efficiency. To obtain a variable speed response, brushless motors operate in an electromechanical system that includes an electronic motor controller and a rotor position feedback sensor. Brushless DC motors are widely used as servomotors for machine tool servo drives. Servomotors are used for mechanical displacement, positioning or precision motion control. DC stepper motors can also be used as servomotors; however, since they are operated with open loop control, they typically exhibit torque pulsations.


title: Brushless DC electric motor

text: Brushless motors are used in industrial positioning and actuation applications. For assembly robots, Brushless technogy may be used to build linear motors. The advantage of linear motors is that they can produce linear motion without the need of a transmission system, such as ballscrews, leadscrew, rack-and-pinion, cam, gears or belts, that would be necessary for rotary motors. Transmission systems are known to introduce less responsiveness and reduced accuracy. Direct drive, brushless DC linear motors consist of a slotted stator with magnetic teeth and a moving actuator, which has permanent magnets and coil windings. To obtain linear motion, a motor controller excites the coil windings in the actuator causing an interaction of the magnetic fields resulting in linear motion. Tubular linear motors are another form of linear motor design operated in a similar way.


title: Brushless DC electric motor

text: Brushless motors have become a popular motor choice for model aircraft including helicopters and drones. Their favorable power-to-weight ratios and wide range of available sizes have revolutionized the market for electric-powered model flight, displacing virtually all brushed electric motors, except for low powered inexpensive often toy grade aircraft. They have also encouraged growth of simple, lightweight electric model aircraft, rather than the previous internal combustion engines powering larger and heavier models. The increased power-to-weight ratio of modern batteries and brushless motors allows models to ascend vertically, rather than climb gradually. The low noise and lack of mass compared to small glow fuel internal combustion engines is another reason for their popularity.


title: Brushless DC electric motor

text: Legal restrictions for the use of combustion engine driven model aircraft in some countries, most often due to potential for noise pollution—even with purpose-designed mufflers for almost all model engines being available over the most recent decades—have also supported the shift to high-power electric systems.


title: Brushless DC electric motor

text: Their popularity has also risen in the radio-controlled (RC) car area. Brushless motors have been legal in North American RC car racing in accordance with Radio Operated Auto Racing (ROAR) since 2006. These motors provide a great amount of power to RC racers and, if paired with appropriate gearing and high-discharge lithium polymer (Li-Po) or lithium iron phosphate (LiFePO4) batteries, these cars can achieve speeds over .


title: Brushless DC electric motor

text: Brushless motors are capable of producing more torque and have a faster peak rotational speed compared to nitro- or gasoline-powered engines. Nitro engines peak at around 46,800 r/min and , while a smaller brushless motor can reach 50,000 r/min and . Larger brushless RC motors can reach upwards of and 28,000 r/min to power one-fifth-scale models.


title: Rajkummar Rao filmography

text: Indian actor Rajkummar Rao made his lead film debut with Dibakar Banerjee's found footage anthology film "Love Sex Aur Dhokha" (2010). After a few supporting roles in films like "Gangs of Wasseypur – Part 2" (2012) and "", his breakthrough came with the drama film "Kai Po Che!" in 2013. He rose to prominence with his portrayal of a lawyer Shahid Azmi in Hansal Mehta's critically acclaimed biographical drama "Shahid" (2013), for which he was awarded the National Film Award for Best Actor and the Filmfare Critics Award for Best Actor.


title: Rajkummar Rao filmography

text: Rao went on to feature in the successful romantic comedy "Queen" (2014), "Aligarh" (2016) and "Trapped" (2016). "Trapped" earned him a second Filmfare Critics Award for Best Actor. Among his 2017 releases, the romantic comedy "Bareilly Ki Barfi" and the black comedy "Newton" were both commercial successes and won him several accolades; the Filmfare Award for Best Supporting Actor for the former and the Asia Pacific Screen Award for Best Actor for the latter. In 2018, he starred in the horror-comedy "Stree", which is the highest-grossing film of his career to date.


title: Adverb

text: An adverb is a word or an expression that generally modifies a verb, adjective, another adverb, determiner, clause, preposition, or sentence. Adverbs typically express manner, place, time, frequency, degree, level of certainty, etc., answering questions such as "how", "in what way", "when", "where", "to what extent". This is called the adverbial function and may be performed by single words (adverbs) or by multi-word adverbial phrases and adverbial clauses.


title: Adverb

text: Adverbs are traditionally regarded as one of the parts of speech. Modern linguists note that the term "adverb" has come to be used as a kind of "catch-all" category, used to classify words with various types of syntactic behavior, not necessarily having much in common except that they do not fit into any of the other available categories (noun, adjective, preposition, etc.)


title: Adverb

text: The English word "adverb" derives (through French) from Latin "adverbium", from "ad-" ("to"), "verbum" ("word", "verb"), and the nominal suffix "-ium". The term implies that the principal function of adverbs is to act as modifiers of verbs or verb phrases. An adverb used in this way may provide information about the manner, place, time, frequency, certainty, or other circumstances of the activity denoted by the verb or verb phrase. Some examples:


title: Adverb

text: Adverbs can also be used as modifiers of adjectives, and of other adverbs, often to indicate degree. Examples:


title: Adverb

text: They can also modify determiners, prepositional phrases, or whole clauses or sentences, as in the following examples:


title: Adverb

text: Adverbs thus perform a wide range of modifying functions. The major exception is the function of modifier of nouns, which is performed instead by adjectives (compare "she sang loudly" with "her loud singing disturbed me"; here the verb "sang" is modified by the adverb "loudly", whereas the noun "singing" is modified by the adjective "loud"). However, because some adverbs and adjectives are homonyms, their respective functions are sometimes conflated:


title: Adverb

text: The word "even" in the first sentence is an adjective, since it is a prepositive modifier that modifies the noun "numbers". The word "even" in the second sentence is a prepositive adverb that modifies the verb "drank."


title: Adverb

text: Although it is possible for an adverb to precede or to follow a noun or a noun phrase, the adverb nonetheless does "not" modify either in such cases, as in:


title: Adverb

text: In the first sentence, "Internationally" is a prepositive adverb that modifies the clause, "there is ..." In the second sentence, "internationally" is a postpositive adverb that modifies the clause, "There is ..." By contrast, the third sentence contains "international" as a prepositive adjective that modifies the noun, "shortage."


title: Adverb

text: Adverbs can sometimes be used as predicative expressions; in English, this applies especially to adverbs of location:


title: Adverb

text: When the function of an adverb is performed by an expression consisting of more than one word, it is called an adverbial phrase or adverbial clause, or simply an adverbial.


title: Adverb

text: In English, adverbs of manner (answering the question "how?") are often formed by adding "-ly" to adjectives, but flat adverbs (such as in "drive fast", "drive slow", and "drive friendly") have the same form as the corresponding adjective. Other languages often have similar methods for deriving adverbs from adjectives (French, for example, uses the suffix "-ment"), or else use the same form for both adjectives and adverbs, as in German and Dutch, where for example "schnell" or "snel", respectively, mean either "quick" or "quickly" depending on the context. Many other adverbs, however, are not related to adjectives in this way; they may be derived from other words or phrases, or may be single morphemes. Examples of such adverbs in English include "here, there, together, yesterday, aboard, very, almost", etc.


title: Adverb

text: Where the meaning permits, adverbs may undergo comparison, taking comparative and superlative forms. In English this is usually done by adding "more" and "most" before the adverb ("more slowly, most slowly"), although there are a few adverbs that take inflected forms, such as "well", for which "better" and "best" are used.


title: Adverb

text: For more information about the formation and use of adverbs in English, see . For other languages, see below, and the articles on individual languages and their grammars.


title: Adverb

text: Adverbs are considered a part of speech in traditional English grammar, and are still included as a part of speech in grammar taught in schools and used in dictionaries. However, modern grammarians recognize that words traditionally grouped together as adverbs serve a number of different functions. Some describe adverbs as a "catch-all" category that includes all words that do not belong to one of the other parts of speech.


title: Adverb

text: A logical approach to dividing words into classes relies on recognizing which words can be used in a certain context. For example, the only type of word that can be inserted in the following template to form a grammatical sentence is a noun:


title: Adverb

text: When this approach is taken, it is seen that adverbs fall into a number of different categories. For example, some adverbs can be used to modify an entire sentence, whereas others cannot. Even when a sentential adverb has other functions, the meaning is often not the same. For example, in the sentences "She gave birth naturally" and "Naturally, she gave birth", the word "naturally" has different meanings: in the first sentence, as a verb-modifying adverb, it means "in a natural manner", while in the second sentence, as a sentential adverb, it means something like "of course".


title: Adverb

text: Words like "very" afford another example. We can say "Perry is very fast", but not "Perry very won the race". These words can modify adjectives but not verbs. On the other hand, there are words like "here" and "there" that cannot modify adjectives. We can say "The sock looks good there" but not "It is a there beautiful sock". The fact that many adverbs can be used in more than one of these functions can confuse the issue, and it may seem like splitting hairs to say that a single adverb is really two or more words that serve different functions. However, this distinction can be useful, especially when considering adverbs like "naturally" that have different meanings in their different functions. Rodney Huddleston distinguishes between a "word" and a "lexicogrammatical-word".


title: Adverb

text: Grammarians find difficulty categorizing negating words, such as the English "not". Although traditionally listed as an adverb, this word does not behave grammatically like any other, and it probably should be placed in a class of its own.


title: Miracles of Jesus

text: The miracles of Jesus are miraculous deeds attributed to Jesus in Christian and Islamic texts. The majority are faith healings, exorcisms, resurrections, and control over nature.


title: Miracles of Jesus

text: In the Synoptic Gospels (Mark, Matthew, and Luke), Jesus refuses to give a miraculous sign to prove his authority. In the Gospel of John, Jesus is said to have performed seven miraculous signs that characterize his ministry, from changing water into wine at the start of his ministry to raising Lazarus from the dead at the end.


title: Miracles of Jesus

text: For many Christians and Muslims, the miracles are actual historical events. Others, including many liberal Christians, consider these stories to be figurative. Since the Enlightenment, many scholars have taken a highly skeptical approach to claims about miracles.


title: Miracles of Jesus

text: In most cases, Christian authors associate each miracle with specific teachings that reflect the message of Jesus.


title: Miracles of Jesus

text: In "The Miracles of Jesus", H. Van der Loos describes two main categories of miracles attributed to Jesus: those that affected people, e.g., the Blind Man of Bethsaida and are called "healings", and those that "controlled nature", e.g., Walking on Water. The three types of healings are "cures" where an ailment is cured, "exorcisms" where demons are cast away and the "resurrection of the dead". Karl Barth said that, among these miracles, the Transfiguration of Jesus is unique in that the miracle happens to Jesus himself.


title: Miracles of Jesus

text: According to Craig Blomberg, one characteristic shared among all miracles of Jesus in the Gospel accounts is that he delivered benefits freely and never requested or accepted any form of payment for his healing miracles, unlike some high priests of his time who charged those who were healed. In he advised his disciples to heal the sick without payment and stated: "freely ye received, freely give."


title: Miracles of Jesus

text: It is not always clear when two reported miracles refer to the same event. For example, in the healing the centurion's servant, the Gospels of Matthew and Luke narrate how Jesus healed the servant of a centurion in Capernaum at a distance. The Gospel of John has a similar but slightly different account at Capernaum, and states that it was the son of a royal official who was cured at a distance.


title: Miracles of Jesus

text: The largest group of miracles mentioned in the New Testament involves cures. The Gospels give varying amounts of detail for each episode, sometimes Jesus cures simply by saying a few words, at other times, he employs material such as spit and mud. Generally they are referred to in the Synoptic Gospels but not in the Gospel of John.


title: Miracles of Jesus

text: The canonical Gospels tell a number of stories of Jesus healing blind people. The earliest is a story of the healing of a blind man in Bethsaida in the Gospel of Mark.


title: Miracles of Jesus

text: Mark's Gospel also has an account of the healing of a man named Bartimaeus, done as Jesus is leaving Jericho. The Gospel of Matthew has a simpler account loosely based on this, with two unnamed blind men instead of one (this 'doubling' is a characteristic of Matthew's treatment of the Mark text) and a slightly different version of the story, taking place in Galilee, earlier in the narrative. The Gospel of Luke tells the same story of Jesus healing an unnamed blind man, but moves the event in the narrative to when Jesus approaches Jericho.


title: Miracles of Jesus

text: The Gospel of John describes an episode in which Jesus heals a man blind from birth, placed during the Festival of Tabernacles, about six months before his crucifixion. Jesus mixes spittle with dirt to make a mud mixture, which he then places on the man's eyes. He instructs the man to wash his eyes in the Pool of Siloam. When the man does this, he is able to see. When asked by his disciples whether the cause of the blindness was the sins of the man's father or his mother, Jesus states that it was neither.


title: Miracles of Jesus

text: A story in which Jesus cures a leper appears in , and . Having cured the man, he instructs him to offer the requisite ritual sacrifices as prescribed by the Deuteronomic Code and Priestly Code, and not to tell anyone who had healed him; but the man disobeyed, increasing Jesus' fame, and thereafter Jesus withdrew to "deserted places", but was followed there.


title: Miracles of Jesus

text: In an episode in the Gospel of Luke , while on his way to Jerusalem, Jesus sends ten lepers who sought his assistance to the priests, and they were healed as they go, but the only one who comes back to thank Jesus is a Samaritan.


title: Miracles of Jesus

text: Healing the paralytic at Capernaum appears in –, and . The Synoptics state that a paralytic was brought to Jesus on a mat; Jesus told him to "get up and walk", and the man did so. Jesus also told the man that his sins were forgiven, which irritated the Pharisees. Jesus is described as responding to the anger by asking whether it is easier to say that someone's sins are forgiven, or to tell the man to "get up and walk". Mark and Luke state that Jesus was in a house at the time, and that the man had to be lowered through the roof by his friends due to the crowds blocking the door.


title: Miracles of Jesus

text: A similar cure is described in the Gospel of John as the healing the paralytic at Bethesda and occurs at the Pool of Bethesda. In this cure Jesus also tells the man to take his mat and walk.


title: Miracles of Jesus

text: The cure of a bleeding woman miracle appears in , and , along with the miracle of the Daughter of Jairus. The Gospels state that while heading to Jairus' house Jesus was approached by a woman who had been bleeding for 12 years, and that she touched Jesus' cloak (fringes of his garment) and was instantly healed. Jesus turned about and, when the woman came forward, said "Daughter, your faith has healed you, go in peace".


title: Miracles of Jesus

text: Healing the mother of Peter's wife. The Synoptics describe Jesus as healing the mother-in-law of Simon Peter when he visited Simon's house in Capernaum, around the time of Jesus recruiting Simon as an Apostle (Mark has it just after the calling of Simon, while Luke has it just before). The Synoptics imply that this led other people to seek out Jesus.


title: Miracles of Jesus

text: Jesus healing an infirm woman appears in . While teaching in a synagogue on a Sabbath, Jesus cured a woman who had been crippled by a spirit for eighteen years and could not stand straight at all.


title: Miracles of Jesus

text: The healing of a man with dropsy is described in . In this miracle, Jesus cured a man with dropsy at the house of a prominent Pharisee on the Sabbath. Jesus justified the cure by asking: "If one of you has a child or an ox that falls into a well on the Sabbath day, will you not immediately pull it out?"


title: Miracles of Jesus

text: In the healing of the man with a withered hand miracle, the Synoptics state that Jesus entered a synagogue on Sabbath, and found a man with a "withered" hand there, whom Jesus healed, having first challenged the people present to decide what was lawful for Sabbath—"to do good or to do evil, to save life or to kill". The Gospel of Mark adds that this angered the Pharisees so much that they started to contemplate killing Jesus.


title: Miracles of Jesus

text: The miraculous healing the deaf mute of Decapolis only appears in the Gospel of Mark. The Gospel states that Jesus went to the Decapolis and met a man there who was deaf and mute, and cured him. Specifically, Jesus first touched the man's ears, and touched his tongue after spitting, and then said Ephphatha!, an Aramaic word meaning "Be opened."


title: Miracles of Jesus

text: The healing of Malchus was Christ's final miracle before his resurrection. Simon Peter had cut off the ear of the High Priest's servant, Malchus, during the scene in the Garden of Gethsemane. Jesus restored the ear by touching it with his hand.


title: Miracles of Jesus

text: The miraculous healing of a centurion's servant is reported in and . These two Gospels narrate how Jesus healed the servant of a centurion in Capernaum. has a similar account at Capernaum, but states that it was the son of a royal official who was healed. In both cases the healing took place at a distance.


title: Miracles of Jesus

text: Jesus healing in the land of Gennesaret appears in and . As Jesus passes through Gennesaret all those who touch his cloak are healed.


title: Miracles of Jesus

text: According to the three Synoptic Gospels, Jesus performed many exorcisms of demoniacs. These incidents are not mentioned in the Gospel of John and appear to have been excluded due to theological considerations.


title: Miracles of Jesus

text: The seven major exorcism accounts in the Synoptic Gospels which have details, and imply specific teachings, are:


title: Miracles of Jesus

text: All four canonical gospels describe the resurrection of Jesus; three of them also relate a separate occasion on which Jesus calls a dead person back to life:


title: Miracles of Jesus

text: "The Book of Mormon", one of the religious texts of the Church of Jesus Christ of Latter-day Saints, records multiple miracles performed by Jesus. Sometime shortly after his Ascension, "The Book of Mormon" records that Jesus miraculously descends from Heaven and greets a large group of people who immediately bow down to him. Jesus invites them to "Arise and come forth unto me, that ye may thrust your hands into my side, and also that ye may feel the prints of the nails in my hands and in my feet, that ye may know that I am the God of Israel, and the God of the whole earth, and have been slain for the sins of the world." "3 Nephi 11:8–17"


title: Miracles of Jesus

text: In addition to descending from Heaven, other miracles of Jesus found in "The Book of Mormon" include:


title: Miracles of Jesus

text: Accounts of Jesus performing miracles are also found outside the New Testament. Later, 2nd century texts, called Infancy Gospels, narrate Jesus performing miracles during his childhood.


title: Miracles of Jesus

text: Miracles performed by Jesus are mentioned in two sections of the Quran (suras 3:49 and 5:110) in broad strokes with little detail or comment.


title: Miracles of Jesus

text: Miracles were widely believed in around the time of Jesus. Gods and demigods such as Heracles (better known by his Roman name, Hercules), Asclepius (a Greek physician who became a god) and Isis of Egypt all were thought to have healed the sick and overcome death (i.e. have raised people from the dead). Some thought that mortal men, if sufficiently famous and virtuous, could do likewise; there were myths about philosophers like Pythagoras and Empedocles calming storms at sea, chasing away pestilences, and being greeted as gods, and similarly some Jews believed that Elisha the Prophet had cured lepers and restored the dead. The achievements of the 1st century Apollonius of Tyana, though occurring after Jesus' life, were used by a 3rd-century opponent of the Christians to argue that Christ was neither original nor divine (Eusebius of Caesaria argued against the charge).


title: Miracles of Jesus

text: The first Gospels were written against this background of Hellenistic and Jewish belief in miracles and other wondrous acts as signs—the term is explicitly used in the Gospel of John to describe Jesus' miracles—seen to be validating the credentials of divine wise men.


title: Miracles of Jesus

text: Many Christians believe Jesus' miracles were historical events and that his miraculous works were an important part of his life, attesting to his divinity and the Hypostatic union, i.e., the dual natures of Jesus as God and Man. They see Jesus' experiences of hunger, weariness, and death as evidences of his humanity, and miracles as evidences of his divinity.


title: Miracles of Jesus

text: Christian authors also view the miracles of Jesus not merely as acts of power and omnipotence, but as works of love and mercy, performed not with a view to awe by omnipotence, but to show compassion for sinful and suffering humanity. And each miracle involves specific teachings.


title: Miracles of Jesus

text: Since according to the Gospel of John, it was impossible to narrate all of the miracles performed by Jesus, the Catholic Encyclopedia states that the miracles presented in the Gospels were selected for a twofold reason: first for the manifestation of God's glory, and then for their evidential value. Jesus referred to his "works" as evidences of his mission and his divinity, and in he declared that his miracles have greater evidential value than the testimony of John the Baptist. quotes Jesus as follows:


title: Miracles of Jesus

text: Do not believe me unless I do what my Father does. But if I do it, even though you do not believe me, believe the miracles, that you may know and understand that the Father is in me, and I in the Father.