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The steam engine, the major driver in the Industrial Revolution, underscores the importance of engineering in modern history. This beam engine is on display in the Technical University of Madrid.

Engineering is the practice of using natural science, mathematics, and the engineering design process to solve technical problems, increase efficiency and productivity, and improve systems. Modern engineering comprises many subfields which include designing and improving infrastructure, machinery, vehicles, electronics, materials, and energy systems.

The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied mathematics, applied science, and types of application. See glossary of engineering.

The term engineering is derived from the Latin ingenium, meaning "cleverness". (Full article...)

Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the limitations imposed by practicality, regulation, safety and cost. The word engineer (Latin ingeniator, the origin of the Ir. in the title of engineer in countries like Belgium, The Netherlands, and Indonesia) is derived from the Latin words ingeniare ("to contrive, devise") and ingenium ("cleverness"). The foundational qualifications of a licensed professional engineer typically include a four-year bachelor's degree in an engineering discipline, or in some jurisdictions, a master's degree in an engineering discipline plus four to six years of peer-reviewed professional practice (culminating in a project report or thesis) and passage of engineering board examinations. (Full article...)

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The production of renewable energy in Scotland is an issue that has come to the fore in technical, economic, and political terms during the opening years of the 21st century. The natural resource base for renewable energy is extraordinary by European, and even global standards, with the most important potential sources being wind, wave, and tide.

At the end of 2015, there was 7,723 megawatts (MW) of installed renewable electricity capacity in Scotland, an increase of 5.5% (or 406 MW) from the end of 2014. Renewable electricity generation in Scotland was 21,983 GWh in 2015, up 15.2% on 2014. 57.7 per cent of Scotland's electricity came from renewables in 2015. Scottish renewable generation makes up approximately 26.4% of total UK renewable generation (down from 32% in 2014). In 2014, Scotland exported over 24 per cent of generation. (Full article...)

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Simple electrical network consisting of two meshes and the following components: two voltage sources and 4 resistors.
Simple electrical network consisting of two meshes and the following components: two voltage sources and 4 resistors.
An electrical network is an interconnection of electrical components (e.g. batteries, resistors, inductors, capacitors, switches) or a model of such an interconnection, consisting of electrical elements (e.g. voltage sources, current sources, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Linear electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are linearly superimposable. They are thus more easily analyzed, using powerful frequency domain methods such as Laplace transforms, to determine DC response, AC response, and transient response. A resistive circuit is a circuit containing only resistors and ideal current and voltage sources. Analysis of resistive circuits is less complicated than analysis of circuits containing capacitors and inductors. If the sources are constant (DC) sources, the result is a DC circuit.

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  • Image 1 A post-war Little Boy model Little Boy is the name of the type of atomic bomb used in the bombing of the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped from the Boeing B-29 Superfortress Enola Gay piloted by Colonel Paul W. Tibbets Jr., commander of the 509th Composite Group, and Captain Robert A. Lewis. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ) and had an explosion radius of approximately 1.3 kilometers which caused widespread death across the city. The Hiroshima bombing was the second nuclear explosion in history, after the Trinity nuclear test. Little Boy was developed by Lieutenant Commander Francis Birch's group at the Manhattan Project's Los Alamos Laboratory during World War II, a reworking of their abandoned Thin Man nuclear bomb. Like Thin Man, it was a gun-type fission weapon. It derived its explosive power from the nuclear fission of uranium-235, whereas Thin Man was based on fission of plutonium-239. Fission was accomplished by shooting a hollow cylinder (the "bullet") onto a solid cylinder of the same material (the "target") by means of a charge of nitrocellulose propellant powder. Little Boy contained 64 kilograms (141 lb) of highly enriched uranium, although less than a kilogram underwent nuclear fission. Its components were fabricated at three different plants so that no one would have a copy of the complete design. Unlike the implosion design, which required sophisticated coordination of shaped explosive charges, the gun-type design was considered almost certain to work so it was never tested before its first use at Hiroshima. (Full article...)

    A post-war Little Boy model

    Little Boy is the name of the type of atomic bomb used in the bombing of the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped from the Boeing B-29 Superfortress Enola Gay piloted by Colonel Paul W. Tibbets Jr., commander of the 509th Composite Group, and Captain Robert A. Lewis. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ) and had an explosion radius of approximately 1.3 kilometers which caused widespread death across the city. The Hiroshima bombing was the second nuclear explosion in history, after the Trinity nuclear test.

    Little Boy was developed by Lieutenant Commander Francis Birch's group at the Manhattan Project's Los Alamos Laboratory during World War II, a reworking of their abandoned Thin Man nuclear bomb. Like Thin Man, it was a gun-type fission weapon. It derived its explosive power from the nuclear fission of uranium-235, whereas Thin Man was based on fission of plutonium-239. Fission was accomplished by shooting a hollow cylinder (the "bullet") onto a solid cylinder of the same material (the "target") by means of a charge of nitrocellulose propellant powder. Little Boy contained 64 kilograms (141 lb) of highly enriched uranium, although less than a kilogram underwent nuclear fission. Its components were fabricated at three different plants so that no one would have a copy of the complete design. Unlike the implosion design, which required sophisticated coordination of shaped explosive charges, the gun-type design was considered almost certain to work so it was never tested before its first use at Hiroshima. (Full article...)
  • Image 2 "Thin Man" plutonium gun test casings "Thin Man" was the code name for a proposed plutonium-fueled gun-type nuclear bomb that the United States was developing during the Manhattan Project. Its development was abandoned in 1944 after it was discovered that the spontaneous fission rate of nuclear reactor-bred plutonium was too high for use in a gun-type design due to the high concentration of the isotope plutonium-240. (Full article...)

    "Thin Man" plutonium gun test casings

    "Thin Man" was the code name for a proposed plutonium-fueled gun-type nuclear bomb that the United States was developing during the Manhattan Project. Its development was abandoned in 1944 after it was discovered that the spontaneous fission rate of nuclear reactor-bred plutonium was too high for use in a gun-type design due to the high concentration of the isotope plutonium-240. (Full article...)
  • Image 3 Replica of the original Fat Man bomb "Fat Man" (also known as Mark III) was the codename for the type of nuclear weapon the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second and largest of the only two nuclear weapons ever used in warfare, the first being Little Boy, and its detonation marked the third nuclear explosion in history. The first one was built by scientists and engineers at Los Alamos Laboratory using plutonium manufactured at the Hanford Site and was dropped from the Boeing B-29 Superfortress Bockscar piloted by Major Charles Sweeney. The name Fat Man refers to the early design of the bomb because it had a wide, round shape. Fat Man was an implosion-type nuclear weapon with a solid plutonium core. The first of that type to be detonated was the Gadget in the Trinity nuclear test less than a month earlier on 16 July at the Alamogordo Bombing and Gunnery Range in New Mexico. Two more were detonated during the Operation Crossroads nuclear tests at Bikini Atoll in 1946, and some 120 were produced between 1947 and 1949, when it was superseded by the Mark 4 nuclear bomb. The Fat Man was retired in 1950. (Full article...)

    Replica of the original Fat Man bomb

    "Fat Man" (also known as Mark III) was the codename for the type of nuclear weapon the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second and largest of the only two nuclear weapons ever used in warfare, the first being Little Boy, and its detonation marked the third nuclear explosion in history. The first one was built by scientists and engineers at Los Alamos Laboratory using plutonium manufactured at the Hanford Site and was dropped from the Boeing B-29 Superfortress Bockscar piloted by Major Charles Sweeney.

    The name Fat Man refers to the early design of the bomb because it had a wide, round shape. Fat Man was an implosion-type nuclear weapon with a solid plutonium core. The first of that type to be detonated was the Gadget in the Trinity nuclear test less than a month earlier on 16 July at the Alamogordo Bombing and Gunnery Range in New Mexico. Two more were detonated during the Operation Crossroads nuclear tests at Bikini Atoll in 1946, and some 120 were produced between 1947 and 1949, when it was superseded by the Mark 4 nuclear bomb. The Fat Man was retired in 1950. (Full article...)
  • Image 4 Sir Isaac Lowthian Bell, by Frank Bramley. National Railway Museum, York Sir Isaac Lowthian Bell, 1st Baronet, FRS (18 February 1816 – 20 December 1904) was a British ironmaster and Liberal Party politician from Washington, County Durham. He was described as being "as famous in his day as Isambard Kingdom Brunel". Bell was an energetic and skilful entrepreneur as well as an innovative metallurgist. He was involved in multiple partnerships with his brothers to make iron and alkali chemicals, and with other pioneers including Robert Stirling Newall to make steel cables. He pioneered the large-scale manufacture of aluminium at his Washington works, conducting experiments in its production, and in the production of other chemicals such as the newly discovered element thallium. He was a director of major companies including the North Eastern Railway and the Forth Bridge company, then the largest bridge project in the world. (Full article...)

    Sir Isaac Lowthian Bell, by Frank Bramley. National Railway Museum, York

    Sir Isaac Lowthian Bell, 1st Baronet, FRS (18 February 1816 – 20 December 1904) was a British ironmaster and Liberal Party politician from Washington, County Durham. He was described as being "as famous in his day as Isambard Kingdom Brunel".

    Bell was an energetic and skilful entrepreneur as well as an innovative metallurgist. He was involved in multiple partnerships with his brothers to make iron and alkali chemicals, and with other pioneers including Robert Stirling Newall to make steel cables. He pioneered the large-scale manufacture of aluminium at his Washington works, conducting experiments in its production, and in the production of other chemicals such as the newly discovered element thallium. He was a director of major companies including the North Eastern Railway and the Forth Bridge company, then the largest bridge project in the world. (Full article...)
  • Image 5 The first chicken gun, built in 1942 by the US Civil Aeronautics Administration and the Westinghouse Electric and Manufacturing Company, being fired at a glass panel. A chicken gun or flight impact simulator is a large-diameter, compressed-air gun used to fire bird carcasses at aircraft components in order to simulate high-speed bird strikes during the aircraft's flight. Jet engines and aircraft windshields are particularly vulnerable to damage from such strikes, and are the most common target in such tests. Although various species of bird are used in aircraft testing and certification, the device acquired the common name of "chicken gun" as chickens are the most commonly used 'ammunition' owing to their ready availability. (Full article...)
    The first chicken gun, built in 1942 by the US Civil Aeronautics Administration and the Westinghouse Electric and Manufacturing Company, being fired at a glass panel.


    A chicken gun or flight impact simulator is a large-diameter, compressed-air gun used to fire bird carcasses at aircraft components in order to simulate high-speed bird strikes during the aircraft's flight. Jet engines and aircraft windshields are particularly vulnerable to damage from such strikes, and are the most common target in such tests. Although various species of bird are used in aircraft testing and certification, the device acquired the common name of "chicken gun" as chickens are the most commonly used 'ammunition' owing to their ready availability. (Full article...)
  • Image 6 The Sinclair C5 is a small one-person battery electric recumbent tricycle, technically an "electrically assisted pedal cycle". It was the culmination of Sir Clive Sinclair's long-running interest in electric vehicles. Although widely described as an "electric car", Sinclair characterised it as a "vehicle, not a car". Sinclair had become one of the UK's best-known millionaires, and earned a knighthood, on the back of the highly successful Sinclair Research range of home computers in the early 1980s. He hoped to repeat his success in the electric vehicle market, which he saw as ripe for a new approach. The C5 emerged from an earlier project to produce a small electric car called the C1. After a change in the law, prompted by lobbying from bicycle manufacturers, Sinclair developed the C5 as an electrically powered tricycle with a polypropylene body and a chassis designed by Lotus Cars. It was intended to be the first in a series of increasingly ambitious electric vehicles, but the development of the follow-up C10 and C15 models never progressed further than the drawing board, mostly due to the poor public response to the C5. (Full article...)

    The Sinclair C5 is a small one-person battery electric recumbent tricycle, technically an "electrically assisted pedal cycle". It was the culmination of Sir Clive Sinclair's long-running interest in electric vehicles. Although widely described as an "electric car", Sinclair characterised it as a "vehicle, not a car".

    Sinclair had become one of the UK's best-known millionaires, and earned a knighthood, on the back of the highly successful Sinclair Research range of home computers in the early 1980s. He hoped to repeat his success in the electric vehicle market, which he saw as ripe for a new approach. The C5 emerged from an earlier project to produce a small electric car called the C1. After a change in the law, prompted by lobbying from bicycle manufacturers, Sinclair developed the C5 as an electrically powered tricycle with a polypropylene body and a chassis designed by Lotus Cars. It was intended to be the first in a series of increasingly ambitious electric vehicles, but the development of the follow-up C10 and C15 models never progressed further than the drawing board, mostly due to the poor public response to the C5. (Full article...)
  • Image 7 A hypothetical depiction of a Dyson swarm surrounding a star A Dyson sphere is a hypothetical megastructure that encompasses a star and captures a large percentage of its power output. The concept is a thought experiment that attempts to imagine how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Because only a tiny fraction of a star's energy emissions reaches the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy. The first modern imagining of such a structure was by Olaf Stapledon in his science fiction novel Star Maker (1937). The concept was later explored by the physicist Freeman Dyson in his 1960 paper "Search for Artificial Stellar Sources of Infrared Radiation". Dyson speculated that such structures would be the logical consequence of the escalating energy needs of a technological civilization and would be a necessity for its long-term survival. A signature of such spheres detected in astronomical searches would be an indicator of extraterrestrial intelligence. (Full article...)
    A hypothetical depiction of a Dyson swarm surrounding a star


    A Dyson sphere is a hypothetical megastructure that encompasses a star and captures a large percentage of its power output. The concept is a thought experiment that attempts to imagine how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Because only a tiny fraction of a star's energy emissions reaches the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy.

    The first modern imagining of such a structure was by Olaf Stapledon in his science fiction novel Star Maker (1937). The concept was later explored by the physicist Freeman Dyson in his 1960 paper "Search for Artificial Stellar Sources of Infrared Radiation". Dyson speculated that such structures would be the logical consequence of the escalating energy needs of a technological civilization and would be a necessity for its long-term survival. A signature of such spheres detected in astronomical searches would be an indicator of extraterrestrial intelligence. (Full article...)
  • Image 8 Group photograph of Project Alberta on Tinian Project Alberta, also known as Project A, was a section of the Manhattan Project which assisted in delivering the first nuclear weapons in the atomic bombing of Hiroshima and Nagasaki during World War II. Project Alberta was formed in March 1945, and consisted of 51 United States Army, Navy, and civilian personnel, including one British scientist. Its mission was three-fold. It first had to design a bomb shape for delivery by air, then procure and assemble it. It supported the ballistic testing work at Wendover Army Air Field, Utah, conducted by the 216th Army Air Forces Base Unit (Project W-47), and the modification of B-29s to carry the bombs (Project Silverplate). After completion of its development and training missions, Project Alberta was attached to the 509th Composite Group at North Field, Tinian, where it prepared facilities, assembled and loaded the weapons, and participated in their use. (Full article...)

    Group photograph of Project Alberta on Tinian

    Project Alberta, also known as Project A, was a section of the Manhattan Project which assisted in delivering the first nuclear weapons in the atomic bombing of Hiroshima and Nagasaki during World War II.

    Project Alberta was formed in March 1945, and consisted of 51 United States Army, Navy, and civilian personnel, including one British scientist. Its mission was three-fold. It first had to design a bomb shape for delivery by air, then procure and assemble it. It supported the ballistic testing work at Wendover Army Air Field, Utah, conducted by the 216th Army Air Forces Base Unit (Project W-47), and the modification of B-29s to carry the bombs (Project Silverplate). After completion of its development and training missions, Project Alberta was attached to the 509th Composite Group at North Field, Tinian, where it prepared facilities, assembled and loaded the weapons, and participated in their use. (Full article...)
  • Image 9 A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input. The simplest of these circuits is a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage. The switching elements are simple diodes and they are driven to switch state merely by the alternating voltage of the input. DC-to-DC voltage doublers cannot switch in this way and require a driving circuit to control the switching. They frequently also require a switching element that can be controlled directly, such as a transistor, rather than relying on the voltage across the switch as in the simple AC-to-DC case. (Full article...)
    A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input.

    The simplest of these circuits is a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage. The switching elements are simple diodes and they are driven to switch state merely by the alternating voltage of the input. DC-to-DC voltage doublers cannot switch in this way and require a driving circuit to control the switching. They frequently also require a switching element that can be controlled directly, such as a transistor, rather than relying on the voltage across the switch as in the simple AC-to-DC case. (Full article...)
  • Image 10 Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. (Full article...)
    Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms.

    New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. (Full article...)
  • Image 11 Joyner analyzing the operation of a wind tunnel turbine at NACA Langley in 1952 Kitty Wingfield Joyner (née O'Brien; July 11, 1916 – August 16, 1993) was an American electrical engineer with the National Advisory Committee for Aeronautics (NACA), and then with the National Aeronautics and Space Administration (NASA) upon its replacement of NACA in 1958. She was the first woman to graduate from the University of Virginia's engineering program in 1939, receiving the Algernon Sydney Sullivan Award upon graduation. When she was hired by NACA the same year, she became the first woman engineer at the organization, eventually rising to the title of Branch Head and managing several of its wind tunnels. Her work contributed to research on aeronautics, supersonic flight, airfoils, and aircraft design standards. (Full article...)

    Joyner analyzing the operation of a wind tunnel turbine at NACA Langley in 1952

    Kitty Wingfield Joyner (née O'Brien; July 11, 1916 – August 16, 1993) was an American electrical engineer with the National Advisory Committee for Aeronautics (NACA), and then with the National Aeronautics and Space Administration (NASA) upon its replacement of NACA in 1958. She was the first woman to graduate from the University of Virginia's engineering program in 1939, receiving the Algernon Sydney Sullivan Award upon graduation. When she was hired by NACA the same year, she became the first woman engineer at the organization, eventually rising to the title of Branch Head and managing several of its wind tunnels. Her work contributed to research on aeronautics, supersonic flight, airfoils, and aircraft design standards. (Full article...)
  • Image 12 The radius of maximum wind of a tropical cyclone lies just within the eyewall of an intense tropical cyclone, such as Hurricane Isabel from 2003 The radius of maximum wind (RMW) is the distance between the center of a cyclone and its band of strongest winds. It is a parameter in atmospheric dynamics and tropical cyclone forecasting. The highest rainfall rates occur near the RMW of tropical cyclones. The extent of a cyclone's storm surge and its maximum potential intensity can be determined using the RMW. As maximum sustained winds increase, the RMW decreases. Recently, RMW has been used in descriptions of tornadoes. When designing buildings to prevent against failure from atmospheric pressure change, RMW can be used in the calculations. (Full article...)
    The radius of maximum wind of a tropical cyclone lies just within the eyewall of an intense tropical cyclone, such as Hurricane Isabel from 2003

    The radius of maximum wind (RMW) is the distance between the center of a cyclone and its band of strongest winds. It is a parameter in atmospheric dynamics and tropical cyclone forecasting. The highest rainfall rates occur near the RMW of tropical cyclones. The extent of a cyclone's storm surge and its maximum potential intensity can be determined using the RMW. As maximum sustained winds increase, the RMW decreases. Recently, RMW has been used in descriptions of tornadoes. When designing buildings to prevent against failure from atmospheric pressure change, RMW can be used in the calculations. (Full article...)
  • Image 13 Male HDMI "type A" connector High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for analog video standards. HDMI implements the ANSI/CTA-861 standard, which defines video formats and waveforms, transport of compressed and uncompressed LPCM audio, auxiliary data, and implementations of the VESA EDID. CEA-861 signals carried by HDMI are electrically compatible with the CEA-861 signals used by the Digital Visual Interface (DVI). No signal conversion is necessary, nor is there a loss of video quality when a DVI-to-HDMI adapter is used. The Consumer Electronics Control (CEC) capability allows HDMI devices to control each other when necessary and allows the user to operate multiple devices with one handheld remote control device. (Full article...)

    Male HDMI "type A" connector

    High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for analog video standards.

    HDMI implements the ANSI/CTA-861 standard, which defines video formats and waveforms, transport of compressed and uncompressed LPCM audio, auxiliary data, and implementations of the VESA EDID. CEA-861 signals carried by HDMI are electrically compatible with the CEA-861 signals used by the Digital Visual Interface (DVI). No signal conversion is necessary, nor is there a loss of video quality when a DVI-to-HDMI adapter is used. The Consumer Electronics Control (CEC) capability allows HDMI devices to control each other when necessary and allows the user to operate multiple devices with one handheld remote control device. (Full article...)
  • Image 14 Schematic representation of the Dirac delta function by a line surmounted by an arrow. The height of the arrow is usually meant to specify the value of any multiplicative constant, which will give the area under the function. The other convention is to write the area next to the arrowhead. In mathematical analysis, the Dirac delta function (or δ distribution), also known as the unit impulse, is a generalized function on the real numbers, whose value is zero everywhere except at zero, and whose integral over the entire real line is equal to one. Thus it can be represented heuristically as '"`UNIQ--postMath-00000001-QINU`"' (Full article...)
    Schematic representation of the Dirac delta function by a line surmounted by an arrow. The height of the arrow is usually meant to specify the value of any multiplicative constant, which will give the area under the function. The other convention is to write the area next to the arrowhead.

    In mathematical analysis, the Dirac delta function (or δ distribution), also known as the unit impulse, is a generalized function on the real numbers, whose value is zero everywhere except at zero, and whose integral over the entire real line is equal to one. Thus it can be represented heuristically as

    (Full article...)
  • Image 15 A Castaing machine, on display at the American Numismatic Association museum. The Castaing machine is a device used to add lettering and decoration to the edge of a coin. Such lettering was necessitated by counterfeiting and edge clipping, which was a common problem resulting from the uneven and irregular hammered coinage. When Aubin Olivier introduced milled coinage to France, he also developed a method of marking the edges with lettering which would make it possible to detect if metal had been shaved from the edge. This method involved using a collar, into which the metal flowed from the pressure of the press. This technique was slower and more costly than later methods. France abandoned milled coinage in favour of hammering in 1585. England experimented briefly with milled coinage, but it wasn't until Peter Blondeau brought his method of minting coins there in the mid-seventeenth century that such coinage began in earnest in that country. Blondeau also invented a different method of marking the edge, which was, according to him, faster and less costly than the method pioneered by Olivier. Though Blondeau's exact method was secretive, numismatists have asserted that it likely resembled the later device invented by Jean Castaing. Castaing's machine marked the edges by means of two steel rulers, which, when a coinage blank was forced between them, imprinted legends or designs on its edge. Castaing's device found favour in France, and it was eventually adopted in other nations, including Britain and the United States, but it was eventually phased out by mechanised minting techniques. (Full article...)
    A photograph of a hand-cranked machine
    A Castaing machine, on display at the American Numismatic Association museum.


    The Castaing machine is a device used to add lettering and decoration to the edge of a coin. Such lettering was necessitated by counterfeiting and edge clipping, which was a common problem resulting from the uneven and irregular hammered coinage. When Aubin Olivier introduced milled coinage to France, he also developed a method of marking the edges with lettering which would make it possible to detect if metal had been shaved from the edge. This method involved using a collar, into which the metal flowed from the pressure of the press. This technique was slower and more costly than later methods. France abandoned milled coinage in favour of hammering in 1585.

    England experimented briefly with milled coinage, but it wasn't until Peter Blondeau brought his method of minting coins there in the mid-seventeenth century that such coinage began in earnest in that country. Blondeau also invented a different method of marking the edge, which was, according to him, faster and less costly than the method pioneered by Olivier. Though Blondeau's exact method was secretive, numismatists have asserted that it likely resembled the later device invented by Jean Castaing. Castaing's machine marked the edges by means of two steel rulers, which, when a coinage blank was forced between them, imprinted legends or designs on its edge. Castaing's device found favour in France, and it was eventually adopted in other nations, including Britain and the United States, but it was eventually phased out by mechanised minting techniques. (Full article...)
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