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  Technology is the use of tools, power, and materials, generally for the purposes of production. Almost every human process for getting food and shelter depends on complex technological systems developed over a two and half million-year period when Homo habilis, the ancestors of modern humans, first began to use tools.  
  Muscle to Microelectronics  
  In human prehistory, the only power available was muscle power, augmented by primitive tools such as the wedge or lever. The domestication of animals about 8500 B.C. and invention of the wheel about 2000 B.C. paved the way for the water mill (1st century B.C.) and later the windmill (12th century A.D.). Not until 1712 did an alternative source of power appear in the form of the first working steam engine, constructed by the English inventor Thomas Newcomen. The English chemist and physicist Michael Faraday's demonstration of the dynamo in 1831 revealed the potential of the electrical motor, and in 1876 the German scientist Nikolaus Otto introduced the four-stroke cycle used in the modern internal combustion engine. The 1940s saw the explosion of the first atomic bomb and the subsequent development of the nuclear power industry. Recent concern over the use of nonrenewable power sources and the pollution caused by the burning of fossil fuels has caused technologists to turn increasingly to exploring renewable sources of energy, in particular solar energy, wind energy, and wave power.  
  The earliest materials used by humans were wood, bone, horn, shell, and stone. Metals were rare and/or difficult to obtain, although forms of bronze and iron were in use from 6000 B.C. and 1000 B.C. respectively. The introduction of the blast furnace in the 15th century enabled cast iron to be extracted, but this process remained expensive until the English ironmaker Abraham Darby substituted coke for charcoal in 1709, thus ensuring a plentiful supply of cheap iron at the start of the Industrial Revolution. Rubber, glass, leather, paper, bricks, and porcelain underwent similar processes of trial and error before becoming readily available. From the mid-1800s entirely new materials, synthetics, appeared. First dyes, then plastic and the more versatile celluloid, and later drugs were synthesized, a process continuing into the 1980s with the  
  intermediate technology The simple wind pump is
an example of intermediate technology if it utilizes
local materials and traditional design. In this way,
there is no need for complex maintenance and
repair, nor expensive spare parts.




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  Technology Summary
  Daily online magazine specializing in features associated with technology. It includes access to previous issues.  
  growth of genetic engineering, which enabled the production of synthetic insulin and growth hormones.  
  The utilization of power sources and materials for production frequently lagged behind their initial discovery. The lathe, known in antiquity in the form of a pole powered by a foot treadle, was not fully developed until the 18th century when it was used to produce objects of great precision, ranging from astronomical instruments to mass-produced screws. The realization that gears, cranks, cams, and wheels could operate in harmony to perform complex motion made mechanization possible. With the perfection of the programmable electronic computer in the 1960s, the way lay open for fully automatic plants. The 1960s–90s saw extensive developments in the electronic and microelectronic industries and in the field of communications.  
  The advanced technology (highly automated and specialized) on which modern industrialized society depends is frequently contrasted with the low technology (labor-intensive and unspecialized) that characterizes some developing countries. Intermediate technology is an attempt to adapt scientifically advanced inventions and technologies to less developed areas by using local materials and methods of manufacture.  
  Rethinking the Speedy World
  Part of a larger site maintained by Scientific American, this page covers the diversity of opinions discussed at an international conference concerning the emphasis of speed in technological and industrial development, and its subsequent effects on people's lives.  
  Technology of Energy Conversion  
  Energy is the capacity to do work. It can exist in many different forms and can be converted from one form to another. So-called energy resources are stores of convertible energy. Harnessing resources generally implies converting their energy into electrical form, because electrical energy is easy to convert to other forms and to transmit from place to place, though not to store.  
  Nonrenewable resources include the fossil fuels (coal, oil, and gas) and nuclear-fission fuels, for example, uranium 235. Renewable resources, such as wind, tidal, and geothermal power, have so far been less  
  jet propulsion Two forms of jet engine. In the turbojet, air passing into the air intake
is compressed by the compressor and fed into the combustion chamber where fuel
burns. The hot gases formed are expelled at high speed from the rear of the engine,
driving the engine forward and turning a turbine which drives the compressor. In the
turbofan, some air flows around the combustion chamber and mixes with the exhaust
gases. This arrangement is more efficient and quieter than the turbojet.




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  exploited, although hydroelectric projects are well established, and wind turbines and tidal systems are being developed. The ultimate nonrenewable, but almost inexhaustible energy source, would be nuclear fusion (the way in which energy is generated in the sun), but controlled fusion is a long way off.  
  conversion of nonrenewable energy sources  
  fossil fuels The energy stored in such fossil fuels as coal, oil, and natural gas is converted into useful work or movement in devices known as engines. The fuel is burned to produce heat energy—hence the name "heat engine"—which is then converted into movement. Heat engines can be classified according to the fuel they use such as gasoline or diesel; or according to whether the fuel is burned inside, as in an internal combustion engine; or externally, as in a steam engine; or according to whether they produce a reciprocating or rotary motion. The c0016-01.gifdiesel engine and c0016-01.gifgasoline engine are both internal-combustion engines. Gas c0016-01.gifturbines and c0016-01.gifjet and rocket engines are also considered to be internal-combustion engines because they burn their fuel inside their combustion chambers.  
  Steam Engine
  Basic guide to the principles behind the steam engine. It includes a labeled diagram and explanatory text of the engine in its most well known form—the steam locomotive  
  steam power In conventional power stations boilers convert water into steam to feed steam turbines, which drive the electricity generators. Every boiler has a furnace in which fuel (coal, oil, or gas) is burned to produce hot gases, and a system of tubes in which heat is transferred from the gases to the water. Boilers are also used in steamships, which are propelled by steam turbines, and in steam locomotives.  
  accumulator The lead—acid car battery is a
typical example of an accumulator. The battery
has a set of grids immersed in a sulfuric acid
electrolyte. One set of grids is made of lead (Pb)
and acts as the anode and the other set made
of lead oxide (PbO
2) acts as the cathode.
  chemical energy Chemical energy can be converted into electrical energy in an electrical cell, more commonly known as a battery. The reactions that take place in a simple cell depend on the fact that some metals are more reactive than others. If an electrolyte and a wire join two different metals, the more reactive metal loses electrons to form ions. The ions pass into solution in the electrolyte, while the electrons flow down the wire to the less reactive metal. At the less reactive metal the electrons are taken up by the positive ions in the electrolyte, which completes the circuit.  
  A fuel cell converts chemical energy directly to electrical energy. It works on the same principle as a battery but is continually fed with fuel, usually hydrogen. Fuel cells are silent and reliable (no moving parts) but expensive to produce.  
  nuclear energy Nuclear reactors are used to produce nuclear energy in a controlled manner. There are various types of reactor in use, all using nuclear fission.  
  diesel engine In a diesel engine, fuel is injected on the power stroke into hot
compressed air at the top of the cylinder, where it ignites spontaneously. The
four stages are exactly the same as those of the fourstroke or Otto cycle.




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  In a gas-cooled reactor, a circulating gas under pressure (such as carbon dioxide) removes heat from the core of the reactor, which usually contains natural uranium. Slowing neutrons in the core by using a moderator such as carbon increases the efficiency of the fission process. The reaction is controlled with neutron-absorbing rods made of boron. An advanced gas-cooled reactor (AGR) generally has enriched uranium as its fuel. A water-cooled reactor, such as the steam-generating heavy water (deuterium oxide) reactor, has water circulating through the hot core. The water is converted to steam, which drives turbo-alternators for generating electricity. The most widely used reactor is the pressurized-water reactor (PWR), which contains a sealed system of pressurized water that is heated to form steam in heat exchangers in an external circuit. The fast reactor or fast breeder reactor has no moderator and uses fast neutrons to bring about fission. It uses a mixture of plutonium and uranium oxide as fuel. When operating, uranium is converted to plutonium, which can be extracted and used later as fuel. It is also called the fast breeder because it produces more plutonium than it consumes. Heat is removed from the reactor by a coolant of liquid sodium. Nuclear power generates around 17% of the world's electricity.  
  Advanced Reactors
  Overview of the features of the next generation of nuclear reactors currently being developed around the world. This "nuclear issues briefing paper," from Australia, focuses on the reactors currently being developed in United States, Japan, France, Germany, and Canada.  
  conversion of renewable energy sources  
  hydroelectric power In a typical hydroelectric scheme, whereby electricity is generated by moving water, water stored in a reservoir, often created by damming a river, is piped into water c0016-01.gifturbines, coupled to electricity generators. In pumped storage plants, water flowing through the turbines is recycled. A tidal power station exploits the rise and fall of the tides. About one-fifth of the world's electricity comes from hydroelectric power. Hydroelectric plants have prodigious generating capacities. The Grand Coulee plant in Washington State, United States, has a power output of around 10,000 megawatts.  
  wave power Various schemes to harness the energy of water waves have been advanced since 1973 when an energy shortage threatened and oil prices rose dramatically. In 1974 the British engineer Stephen Salter developed the "duck"—a floating boom, the segments of which nod up and down with the waves. The nodding motion can be used to drive pumps and spin generators. Another device uses an oscillating water column to harness wave power. A major breakthrough will be required if wave power is ever to contribute significantly to the world's energy needs, although several ideas have reached prototype stage.  
  By 1998 wave power devices had improved to such a degree as to have become economically viable. The duck, for example, can generate electricity at 2.6 pence per kilowatt hour, compared with 2.5 pence for a gasfired power station and 4.5 pence for a nuclear-powered one.  
  wind power The wind has long been used as a source of energy: sailing ships and windmills are ancient inventions. After the energy crisis of the 1970s wind turbines began to be used to produce electricity on a large scale. Wind turbines are windmills of advanced aerodynamic design connected to an electricity generator and used in wind-power installations. They can be either large propeller-type rotors mounted on a tall tower, or flexible metal strips fixed to a vertical axle at top and bottom. The world's largest wind turbine is on Hawaü, in the Pacific Ocean. It has two blades 50 m/160 ft long on top of a tower 20 stories high. Other machines use novel rotors, such as the "eggbeater" design developed at Sandia Laboratories in New Mexico, United States. Worldwide, wind turbines on land produce only the energy equivalent of a single nuclear power station.  
  Wind Turbines
  Reports on latest wind turbine research. There are technical details of a variety of experimental turbines, information on the work of companies active in research and development, and speculation about the configurations of the kinds of turbines likely to become significant contributors to energy resources in the next century.  
  geothermal energy Energy extracted from natural steam, hot water, or hot dry rocks in the Earth's crust for heating and electricity generation is an important source of energy in volcanically active areas such as Iceland and New Zealand. Water is pumped down through an injection well where it passes through joints in the hot rocks. It rises to the surface through a recovery well and may be converted to steam or run through a heat exchanger. Dry steam may be directed through turbines to produce electricity.  
  solar energy The amount of energy from the sun's radiation falling on just 1 sq km/0.3861 sq mi is about  




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  geothermal energy Geothermal energy
is derived from the natural heat present below
the surface of the earth. Cool water is pumped
down where it is heated up in large underground
reservoirs before being pumped back to the surface.
  4,000 megawatts: enough to heat and light a small town. Solar heaters have industrial or domestic uses. They usually consist of a black (heat-absorbing) panel containing pipes through which air or water, heated by the sun, is circulated, either by thermal convection or by a pump. Solar energy may also be harnessed indirectly using solar cells (photovoltaic cells) made of panels of semiconductor material (usually silicon), which generate electricity when illuminated by sunlight. Although it is difficult to generate a high output from solar energy compared to sources such as nuclear or fossil fuels, it is a major nonpolluting and renewable energy source.  
  Engineering and Technological Science  
  Engineering is the application of science to the design, construction, and maintenance of works, machinery, roads, railroads, bridges, harbor installations, engines, ships, aircraft and airports, spacecraft and space stations, and the generation, transmission, and use of electrical power. The main divisions of engineering are aerospace, chemical, civil, computer, electrical, electronic, gas, marine, materials, mechanical, mining, production, radio, and structural.  
  civil engineering Civil engineering is concerned with the construction of roads, bridges, airports, aqueducts, waterworks, tunnels, canals, irrigation works, and harbours. The term is thought to have been used for the first time by the British engineer John Smeaton in about 1750 to distinguish civilian from military engineering projects.  
  electronic engineering Electronic engineering deals with the construction of electronic devices. The first electronic device was the thermionic valve, or vacuum tube, in which electrons moved in a vacuum, and led to such inventions as radio, television, c0016-01.gifradar, and the digital computer. Replacement of valves with the comparatively tiny and reliable transistor from 1948 revolutionized electronic development. Modern electronic devices are based on minute integrated circuits (silicon chips), wafer-thin crystal slices holding tens of thousands of electronic components. By using solid-state devices such as integrated circuits, extremely complex electronic circuits can be constructed, leading to the development of digital watches, pocket calculators, powerful microcomputers, and word processors.  
  hydraulic engineering Hydraulic engineering is concerned with utilizing the properties of water and other liquids, in particular the way they flow and transmit pressure. It applies the principles of hydrostatics and hydrodynamics. The oldest type of hydraulic machine is the hydraulic press, invented by Joseph Bramah in England in 1795. The hydraulic principle of pressurized liquid increasing a force is commonly used on  
  hydraulics The hydraulic jack transmits the
pressure on a small piston to a larger one. The
larger piston develops a larger total force but it
moves a smaller distance than the small piston.




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  vehicle braking systems, the forging press, and the hydraulic systems of aircraft and excavators.  
  aeronautics Aeronautics is concerned with travel through the earth's atmosphere, and includes aerodynamics, aircraft structures, jet and rocket propulsion, and aerial navigation. For all flight speeds streamlining is necessary to reduce the effects of air resistance. In subsonic aeronautics (below the speed of sound), aerodynamic forces increase at the rate of the square of the speed. Transonic aeronautics covers the speed range from just below to just above the speed of sound and is crucial to aircraft design. Supersonic aeronautics concerns speeds above that of sound and in one sense may be considered a much older study than aeronautics itself, since the study of the flight of bullets, known as ballistics, was undertaken soon after the introduction of firearms. Hypersonics is the study of airflows and forces at speeds above five times that of sound (Mach 5); for example, for guided missiles, space rockets, and advanced concepts such as HOTOL (horizontal takeoff and landing). Aeronautics is distinguished from astronautics, which is the science of travel through space.  
  American Institute of Aeronautics and Astronautics Home Page
  Access to the AIAA Bulletin. This site also includes details of the institute's research departments, recent conferences, technical activities, and project updates. If the extensive front page doesn't have what you need, the site is also fully-searchable.  
  bionics Bionics (from "biological electronics") deals with the design and development of electronic or mechanical artificial systems that imitate those of living things. The bionic arm, for example, is an artificial limb (prosthesis) that uses electronics to amplify minute electrical signals generated in body muscles to work electric motors, which operate the joints of the fingers and wrist.  
  Chemisty and Industry Magazine
  Latest developments in the fast-changing world of biotechnology. This online edition of Chemistry and Industry has well written and readily understandable articles on biotechnology, chemistry, and the pharmaceutical industry.  
  biotechnology Biotechnology is the industrial use of living organisms to manufacture food, drugs, or other products. The brewing and baking industries have long relied on the yeast microorganism for fermentation purposes, while the dairy industry employs a range of bacteria and fungi to convert milk into cheeses and yogurts. Enzymes, whether extracted from cells or produced artificially, are central to most biotechnological applications.  
  metallurgy Metallurgy is the science and technology of producing metals, which includes extraction, alloying, and hardening. Extractive or process metallurgy is concerned with the extraction of metals from their ores and refining and adapting them for use. Metals can be extracted from their ores in three main ways: dry processes, such as smelting, volatilization, or amalgamation (treatment with mercury); wet processes, involving chemical reactions; and electrolytic processes, which work on the principle of electrolysis (using electricity conducted by a solution or melt to effect chemical changes). Physical metallurgy is concerned with the properties of metals and their applications.  
  Bessemer process In a Bessemer converter, a
blast of high-pressure air oxidizes impurities in
molten iron and converts it to steel.
  nanotechnology Nanotechnology is an experimental technology which uses individual atoms or molecules as the components of minute machines, measured by the nanometer, or millionth of a millimeter. Nanotechnology research in the 1990s focused on testing molecular structures and refining ways to manipulate atoms using a scanning tunneling microscope. The ultimate aim is to create very small computers and molecular machines that can perform vital engineering or medical tasks. The scanning electron microscope can be used to see and position single atoms and molecules, and to drill holes a nanometer across in a variety of materials.  




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  optoelectronics Optoelectronics is the branch of electronics concerned with the development of devices (based on the semiconductor gallium arsenide) that respond not only to the electrons of electronic data transmission, but also to photons. In 1989, scientists at IBM in the United States built a gallium arsenide microprocessor ("chip") containing 8,000 transistors and four photodetectors. The densest optoelectronic chip yet produced, this can detect and process data at a speed of 1 billion bits per second.  
  radiography Radiography is concerned with the use of radiation (particularly X-rays) to produce images on photographic film or fluorescent screens. X-rays penetrate matter according to its nature, density, and thickness. In doing so they can cast shadows on photographic film, producing a radiograph. Radiography is widely used in medicine for examining bones and tissues and in industry for examining solid materials; for example, to check welded seams in pipelines.  
  Technology of Machines  
  A machine is a device that allows a small force (the effort) to overcome a larger one (the load). There are three basic machines: the inclined plane (ramp), the lever, and the wheel and axle. All other machines are combinations of these three basic types. Simple machines or machine components derived from the inclined plane include the wedge, the gear, the pulley, and the screw. The principal features of a machine are its mechanical advantage, which is the ratio of load to effort, its velocity ratio, and its efficiency, which is the work done by the load divided by the work done by the effort; the latter is expressed as a percentage. In a perfect machine, with no friction, the efficiency would be 100%. All practical machines have efficiencies of less than 100%, otherwise perpetual motion would be possible.  
  simple machines  
  inclined plane An inclined plane is a slope that allows a load to be raised gradually using a smaller effort than would be needed if it were lifted vertically upward. It is a force multiplier, possessing a mechanical advantage greater than one. Bolts and screws are based on the principle of the inclined plane.  
  lever A lever is a simple machine consisting of a rigid rod pivoted at a fixed point called the fulcrum, used for shifting or raising a heavy load or applying force. Levers are classified into orders according to where the effort is applied, and the load-moving force developed, in relation to the position of the fulcrum. A first-order lever has the load and the effort on opposite sides of the fulcrum—for example, a see-saw or pair of scissors. A second-order lever has the load and the effort on the same side of the fulcrum, with the load nearer the fulcrum—for example, nutcrackers or a wheelbarrow. A third-order lever has the effort nearer the fulcrum than the load, with both on the same side of it—for example, a pair of tweezers or tongs. The mechanical advantage of a lever is the ratio of load to effort, equal to the perpendicular distance of the effort's line of action from the fulcrum divided by the distance to the load's line of action. Thus tweezers, for instance, have a mechanical advantage of less than one.  
  pulley The mechanical advantage of
a pulley increases with the number
of rope strands. If a pulley system
has four ropes supporting the load,
the mechanical advantage is four,
and a 5 Newton force will lift a 20
Newton load.




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  wheel and axle A wheel and axle consists of a rope wound round an axle connected to a larger wheel with another rope attached to its rim. Pulling on the wheel rope (applying an effort) lifts a load attached to the axle rope. The velocity ratio of the machine (distance moved by load divided by distance moved by effort) is equal to the ratio of the wheel radius to the axle radius. A wheel is defined as a circular disk that supports an object and allows its easy movement.  
  pulley A pulley consists of a fixed, grooved wheel, sometimes in a block, around which a rope or chain can be run. A simple pulley serves only to change the direction of the applied effort (as in a simple hoist for raising loads). The use of more than one pulley results in a mechanical advantage, so that a given effort can raise a heavier load. The mechanical advantage depends on the arrangement of the pulleys. For instance, a block and tackle arrangement with three ropes supporting the load will lift it with one-third of the effort needed to lift it directly (if friction is ignored), giving a mechanical advantage of three.  
  To remember that to tighten a bolt or nut you turn it clockwise (right), and to take it off you turn it counter-clockwise (left):  
  Righty tighty, lefty loosie  


  screw A screw is a cylindrical or tapering piece of metal or plastic with a helical (spiral) groove cut into it. Each turn of a screw moves it forward or backward by a distance equal to the pitch (the spacing between neighboring threads). Its mechanical advantage equals 2rP where P is the pitch and r is the radius of the thread. Thus the mechanical advantage of a tapering wood screw, for example, increases as it is rotated into the wood. The thread is comparable to an inclined plane (wedge) wrapped around a cylinder or cone.  
  wedge A wedge is a block of triangular cross-section that can be used as a simple machine. An ax is a wedge that splits wood by redirecting the energy of the downward blow sideways, where it exerts the force needed to split the wood.  
  major machine components  
  bearing Bearings are used in a machine to allow free movement between two parts, typically the rotation of a shaft in a housing. Ball bearings consist of two rings, one fixed to a housing, one to the rotating shaft. Between them is a set, or race, of steel balls. They are widely used to support shafts, as in the spindle in the hub of a bicycle wheel. The sleeve, or journal bearing, is the simplest bearing. It is a hollow cylinder, split into two halves. It is used for the big-end and main bearings on a car crankshaft. In some machinery the balls of ball bearings are replaced by cylindrical rollers or thinner needle bearings.  
  cam A cam converts circular motion to linear motion or vice versa. The edge cam in a car engine is in the form of a rounded projection on a shaft, the camshaft.  
  clutch The clutch consists of two main plates: a drive plate connected to the engine
crankshaft and a driven plate connected to the wheels. When the clutch is disengaged, the
drive plate does not press against the driven plate. When the clutch is engaged, the two
plates are pressed into contact and the rotation of the crankshaft is transmitted to the wheels.




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  When the camshaft turns, the cams press against linkages (plungers or followers) that open the valves in the cylinders.  
  clutch A clutch is any device for disconnecting rotating shafts, used especially in a car's transmission system. In a car with a manual gearbox, the driver depresses the clutch when changing gear, thus disconnecting the engine from the gearbox.  
  gear A gear is a toothed wheel that transmits the turning movement of one shaft to another shaft. Gear wheels may be used in pairs, or in threes if both shafts are to turn in the same direction. The gear ratio—the ratio of the number of teeth on the two wheels—determines the torque ratio, the turning force on the output shaft compared with the turning force on the input shaft. The ratio of the angular velocities of the shafts is the inverse of the gear ratio.  
  shaft A shaft is a bar, usually cylindrical, used to support rotating pieces of machinery or to transmit power or motion by rotation.  
  spring A spring is a device, usually a metal coil, that returns to its original shape after being stretched or compressed. Springs are used in some machines (such as clocks) to store energy, which can be released at a controlled rate. In other machines (such as engines) they are used to close valves.  
  Technology of Industry  
  Industry is the extraction and conversion of raw materials, the manufacture of goods, and the provision of services. Industry can be either low technology, unspecialized, and labor-intensive, as in countries with a large unskilled labor force, or highly automated, mechanized, and specialized, using advanced technology, as in the industrialized countries. Major recent trends in industrial activity have been the growth of electronic, robotic, and microelectronic technologies.  
  mining Mining entails the extraction of minerals from under the land or sea for industrial or domestic uses. Exhaustion of traditionally accessible resources has led to development of new mining techniques; for example, extraction of oil from offshore deposits and from land shale reserves. Technology is also under development for the exploitation of minerals from entirely new sources such as mud deposits and mineral nodules from the sea bed.  
  refining Refining is any process that purifies or converts something into a more useful form. Metals usually need refining after they have been extracted from their ores by such processes as smelting. Petroleum, or crude oil, needs refining before it can be used; the process involves fractional distillation, the separation of the substance into separate components or ''fractions." Electrolytic metal-refining methods use the principle of electrolysis (conducting electricity in a solution or melt to effect chemical changes) to obtain pure metals. When refining petroleum, or crude oil, further refinery processes after fractionation convert the heavier fractions into more useful lighter products. The most important of these processes is cracking; others include polymerization, hydrogenation, and reforming.  
  Oil Industry: Panoramic Photographs, 1851–1991[email protected](+Oil+Petroleum+))
  Part of the Panoramic Photo Collection of the US Library of Congress, this page features approximately 50 panoramic photographs of the U.S. oil industry taken between 1851 and 1991. Most images are of Texas and California.  
  automation The widespread use of self-regulating machines in industry is known as automation. It involves the addition of control devices, using electronic sensing and computing techniques, which often follow the pattern of human nervous and brain functions, to already mechanized physical processes of production and distribution; for example, steel processing, mining, chemical production, and road, rail, and air control. Automation builds on the process of mechanization to improve manufacturing efficiency.  
  robotics Robotics is the application of any computer-controlled machine that can be programmed to move or carry out work. Robots are often used in industry to transport materials or to perform repetitive tasks. For instance, robotic arms, fixed to a floor or workbench, may be used to paint machine parts or assemble electronic circuits. Other robots are designed to work in situations that would be dangerous to humans—for example, in defusing bombs or in space and deep-sea exploration. Some robots are equipped with sensors, such as touch sensors and video cameras, and can be programmed to make simple decisions based on the sensory data received. As robots do not suffer from fatigue or become distracted, researchers in robotics aim to produce robots that can carry out sophisticated tasks more efficiently than humans.  
  refrigeration Refrigeration is the use of technology to transfer heat from cold to warm, against the normal temperature gradient, so that a refrigeration unit can remain substantially colder than its surroundings. Refrigeration equipment is used for the chilling and deep-freezing of food in food technology, and in air conditioners and industrial processes. Refrigeration is commonly achieved by a vapor-compression cycle, in  




Page 612
  which a suitable chemical (the refrigerant) travels through a long circuit of tubing, during which it changes from a vapor to a liquid and back again. A compression chamber makes it condense, and thus give out heat. In another part of the circuit, called the evaporator coils, the pressure is much lower, so the refrigerant evaporates, absorbing heat as it does so. The evaporation process takes place near the central part of the refrigerator, which therefore becomes colder, while the compression process takes place near a ventilation grille, transferring the heat to the air outside. The most commonly used refrigerants in modern systems were formerly chlorofluorocarbons, but these are now being replaced by coolants that do not damage the ozone layer.  
  food technology The U.S. Food and Drug Administration (FDA) has guidelines for acceptable levels of insect contamination in food. For example it is acceptable to have up to 3 fruitfly maggots per 200 g/7 oz of tomato juice; 100 insect fragments per 25 g/0.8 oz of curry powder; and up to 13 insect heads per 100 g/3.5 oz of fig paste.  
  Technology of Construction Industries  
  bridge A bridge is a structure that provides a continuous path or road over water, valleys, ravines, or above other roads. The basic designs and composites of these are based on the way they bear the weight of the structure and its load. Beam or girder bridges are supported at each end by the ground with the weight thrusting downward. Cantilever bridges are a complex form of girder in which only one end is supported. Arch bridges thrust outward and downward at their ends. Suspension bridges use cables under tension to pull inward against anchorages on either side of the span, so that the roadway hangs from the main cables by the network of vertical cables. The cable-stayed bridge relies on diagonal cables connected directly between the bridge deck and supporting towers at each end. Some bridges are too low to allow traffic to pass beneath easily, so they are designed with movable parts, like swing and draw bridges.  
The Longest Bridges by Span in the World
Bridge Location Date
Suspension spans        
Honshu—Awaji Islands, Japan 1998
  Store Baelt  
Zealand—Funen, Denmark 1997
  Humber Bridge  
Kingston-upon-Hull, U.K. 1973–81
  Verrazono Narrows  
Brooklyn—Staten Island, New York Harbor (NY), U.S.A. 1959–64
  Golden Gate  
San Francisco (CA), U.S.A. 1937
  Mackinac Straits  
Michigan (MI), U.S.A. 1957
Golden Horn, Istanbul, Turkey 1973
  George Washington  
Hudson River, New York (NY), U.S.A. 1927–31
  Ponte 25 Abril (Salazar)  
Tagus River, Lisbon, Portugal 1966
  Firth of Forth (road)  
South Queensferry, U.K. 1958–64
  Severn Bridge  
Beachley, U.K. 1961–66
Cable-stayed spans        
  Pont de Normandie  
Seine Estuary, France 1995
near Trondheim, Norway 1991
Cantilever spans        
  Howrah (railroad)  
Hooghly River, Calcutta, India 1936–43
  Pont de Québec (railroad)  
St Lawrence, Canada 1918
Ravenswood (WV) U.S.A. 1981
  Firth of Forth (rail)  
South Queensferry, U.K. 1882–90
  Commodore Barry  
Chester (PA), U.S.A. 1974
  Greater New Orleans  
Mississippi River (LA), U.S.A. 1958
Steel arch spans        
  New River Gorge  
Fayetteville (WV), U.S.A. 1977
  Bayonne (Killvan Kull)  
New Jersey—Staten Island (NY), U.S.A. 1932
  Sydney Harbour  
Sydney, Australia 1923–32





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The Tallest Buildings in the World
  (N/A = not available.)  
Inhabited buildings        
  Miglin-Beitler Tower1  
Chicago (IL), U.S.A.
  Chongqing Tower  
Chongqing, China
  Petronas Tower3  
Kuala Lumpur, Malaysia
  Sears Tower  
Chicago (IL), U.S.A.
  World Trade Center3  
New York (NY), U.S.A.
  Empire State Building  
New York (NY), U.S.A.
  Bank of China  
Hong Kong, China
  Amoco Building  
Chicago (IL), U.S.A.
  John Hancock Center  
Chicago (IL), U.S.A.
  Chrysler Building  
New York (NY), U.S.A.
  Nations Bank Tower  
Atlanta (GA), U.S.A.
  First Interstate World Center  
Los Angeles (CA), U.S.A.
  Stratosphere Tower  
Las Vegas (NV), U.S.A.
  Texas Commerce Tower  
Houston (TX), U.S.A.
  Allied Bank Plaza  
Houston (TX), U.S.A.
  Two Prudential Plaza  
Chicago (IL), U.S.A.
  311 South Waker Drive  
Chicago (IL), U.S.A.
  First Canadian Place  
Toronto, Ontario, Canada
  American International  
New York (NY), U.S.A.
  Bay/Adelaide Center  
Toronto, Ontario, Canada
  One Liberty Place  
Philadelphia (PA), U.S.A.
  Columbia Seafirst Center  
Seattle (WA), U.S.A.
  40 Wall Tower  
New York (NY), U.S.A.
  Nations Bank Plaza  
Dallas (TX), U.S.A.
  Citicorp Center  
New York (NY), U.S.A.
  Scotia Plaza  
Toronto, Ontario, Canada
  One Peach Tree Center  
Atlanta (GA), U.S.A.
  Transco Tower  
Houston (TX), U.S.A.
  Society Center  
Cleveland (OH), U.S.A.
  Two Union Square  
Seattle (WA), U.S.A.
  AT&T Corporate Center  
Chicago (IL), U.S.A.
  Mellon Bank Center  
Philadelphia (PA), U.S.A.
  Nations Bank Corporate Center  
Charlotte (NC), U.S.A.
  900 North Michigan  
Chicago (IL), U.S.A.
  Canada Trust Tower  
Toronto, Ontario, Canada
  Water Tower Place  
Chicago (IL), U.S.A.
  First Interstate Bank  
Los Angeles (CA), U.S.A.
  Transamerica Pyramid  
San Francisco (CA), U.S.A.
  G. E. Building, Rockefeller Center  
New York (NY), U.S.A.
  One First National Plaza  
Chicago (IL), U.S.A.
  Two Liberty Place  
Philadelphia (PA), U.S.A.
  USX Towers  
Pittsburgh (PA), U.S.A.
  One Atlantic Center  
Atlanta (GA), U.S.A.
New York (NY), U.S.A.
  One Chase Manhattan  
New York (NY), U.S.A.
  Metlife Building  
New York (NY), U.S.A.
  John Hancock Tower  
Boston (MA), U.S.A.
Tallest structures        
  Warszawa Radio Maszt4  
Konstantynadio Maszt
  KTHI-TV Mast  
Fargo (ND), U.S.A.
  CN Tower
Toronto, Ontario, Canada
1 Planned; this will become the tallest inhabited building when completed.
2 Excluding TV antennas.
3 Tallest tower in building listed.
4 Collapsed during renovation, August 1991.





Page 614
  Super Bridge
  Companion to the U.S. Public Broadcasting Service (PBS) television program Nova, this page introduces us to the four major types of bridges and explains why each is designed to span specific locations. Once you have browsed the site, test your knowledge by linking the right bridge with the right feature.  
  dam A dam is a structure built to hold back water in order to prevent flooding, to provide water for irrigation and storage, and to provide hydroelectric power. The biggest dams are of the earth- and rock-fill type, also called embankment dams. Such dams are generally built on broad valley sites. Earth dams have a watertight core wall, formerly made of puddle clay but nowadays constructed of concrete. Their construction is very economical even for very large structures. Rockfill dams are a variant of the earth dam in which dumped rock takes the place of compacted earth fill.  
  Deep, narrow gorges dictate a concrete dam, where the strength of reinforced concrete can withstand the water pressures involved. Many concrete dams are triangular in cross section, with their vertical face pointing upstream. Their sheer weight holds them in position, and so they are called gravity dams. They are no longer favoured for very large dams, however, because they are expensive and time-consuming to build. Other concrete dams are built in the shape of an arch, which transfers the horizontal force into the sides of the river valley: the arch dam derives its strength from the arch shape, just as an arch bridge does, and has been widely used in the 20th century. They require less construction material than other dams and are the strongest type. Buttress dams are used when economy of construction is important or foundation conditions preclude any other type. The upstream portion of a buttress dam may comprise series of cantilevers, slabs, arches, or domes supported from the back by a line of buttresses. They are usually made from reinforced and pre-stressed concrete. In 1997 there were approximately 40,000 large dams (more than 15 m/49 ft in height) and 800,000 small ones worldwide.  
  If it were not for the world's dams holding back river water, sea levels would be 3 cm/1.2 in higher than they are.  
  canal Canals are artificial waterways constructed for drainage, irrigation, or navigation. Irrigation canals carry water for irrigation from rivers, reservoirs, or wells, and are designed to maintain an even flow of water over the whole length. Navigation and ship canals are constructed at one level between locks, and frequently link with rivers or sea inlets to form a waterway system. Where speed is not a prime factor, the cost-effectiveness of transporting goods by canal has encouraged a revival; Belgium, France, Germany, and the states of the former USSR are among countries that have extended and streamlined their canals.  
  tunnel A tunnel is a passageway through a mountain, under a body of water, or underground. The difficulties of tunneling naturally increase with the size, length, and depth of tunnel, but with the mechanical appliances now available no serious limitations are  
The Highest Dams in the World
Source: Institute of Civil Engineers, London
Dam Location
Height above lowest formation
Rogun1 Tajikistan
Nurek Tajikistan
Grand Dixence Switzerland
Inguri Georgia
Boruca1 Costa Rica
Chicoasen Mexico
Tehri1 India
Kambaratinsk1 Kyrgyzstan
Kishau1 India
Sayano-Shushensk1 Russia
Guavio Colombia
Mica Canada
Ertan1 China
Mauvoisin Switzerland
Chivor Colombia
El Cajon Honduras
Chirkey Russia
Oroville U.S.A.
Bekhme1 Iraq
Bhakra India
Hoover U.S.A.
Contra Switzerland
Mratinje Yugoslavia
1 Under construction.





Page 615
  dam There are two basic types of dam: the gravity
dam and the arch dam. The gravity dam relies upon
the weight of its material to resist the forces imposed
upon it; the arch dam uses an arch shape to take the
forces in a horizontal direction into the sides of the river
valley. The largest dams are usually embankment dams.
Buttress dams are used to hold back very wide rivers
or lakes.
  imposed. In recent years there have been notable developments in linings (for example, concrete segments and steel liner plates), and in the use of rotary diggers and cutters and explosives. Small-section tunnels are usually driven from one end to the other at their full dimensions. Large-section tunnels are often driven in two stages; a pilot heading is excavated in advance which is afterwards enlarged to the full section of the main tunnel. The normal procedure in tunneling in rock is as follows. Power drills are used to bore successive rounds of holes in the face. Each round is fired and the broken rock removed by hand shovels or mechanical loaders. In hard rock, blasting is necessary to break down the material. The section is trimmed to its proper size by further blasting or by pneumatic picks, and timber or steel supports are erected. Sometimes side and top lagging boards are required. In loose ground the top laggings are driven in advance of the last supporting set (fore-poling) before the debris is removed. In sand or gravel the problem is one of support rather than excavation, and fore-poling is necessary. The poling pieces are driven along the sides and top of the tunnel to protect the workers from sudden falls or "runs" of ground. In soft ground, tunneling  
Canals and Waterways
Name Country Opened Length (km/mi)
Amsterdam Netherlands 1876 26.6/16.5
Baltic-Volga Russian Federation, Belarus, Ukraine 1964 2,430/1,510
Baltic-White Sea Russian Federation 1933 235/146
Corinth Greece 1893 6.4/4
Elbe and Trave Germany 1900 66/41
Erie U.S.A. 1825 580/360
Göta Sweden 1832 185/115
Grand Canal China 485 B.C.–A.D. 1972 1,050/650
Kiel Germany 1895 98/61
Manchester England 1894 57/35.5
Panama Panama (U.S. zone) 1914 81/50.5
Princess Juliana Netherlands 1935 32/20
St. Lawrence Canada 1959 3,770/2,342
Sault Ste. Marie U.S.A. 1855 2.6/1.6
Sault Ste. Marie Canada 1895 1.8/1.1
Welland Canada 1929 45/28
Suez Egypt 1869 166/103





Page 616
  lock Traveling downstream, a boat enters the lock with the lower
gates closed. The upper gates are then shut and the water level
lowered by draining through sluices. When the water level in the
lock reaches the downstream level, the lower gates are opened.
  shields provide overhead protection, and the support given to the face helps to reduce air losses when air pressure is used to keep water out of the workings. The shield is more easily pushed ahead when the ground immediately adjacent to the shield is replaced with soft, puddled clay. Alignment is laser-controlled to keep the tunnels within a tolerance on position of 30 mm/1.18 in vertically and 300 mm/11.8 in laterally.  
  Technology of Transportation  
  car Originally the automated version of the horse-drawn carriage, a car is a small, driver-guided, passenger-carrying motor vehicle designed to transport people. Most are four-wheeled and have water-cooled, piston-type internal-combustion engines fueled by gasoline or diesel. Variations have existed for decades that use ingenious and often nonpolluting power plants; steam was an attractive form of power to the English pioneers. A typical present-day medium-sized saloon car has a semi-monocoque construction in which the body panels, suitably reinforced, support the road loads through independent front and rear sprung suspension, with seats located within the wheelbase for comfort.  
  A car is usually powered by a petrol engine using a carburetor to mix gasoline and air for feeding to the engine cylinders (typically four or six), and the engine is usually water cooled. In the 1980s high-performance diesel engines were being developed for use in private cars, and it is anticipated that this trend will continue for reasons of economy. From the engine, power is transmitted through a clutch to a four- or five-speed gearbox and from there, in a front-engine rear-drive car, through a drive (propeller) shaft to a differential gear, which drives the rear wheels. In a front-engine,  




Page 617
The Longest Vehicular Tunnels in the World
Tunnel Location Year opened
Saint Gotthard Switzerland 1980
Arlberg Austria 1978
Fréjus France—Italy 1980
Mont Blanc France—Italy 1965
Gran Sasso Italy 1976
Seelisberg Switzerland 1979
Mount Ena Japan 1976
Rokko 11 Japan 1974
San Bernardino Switzerland 1967
Tauren Austria 1974


  front-wheel drive car, clutch, gearbox, and final drive are incorporated with the engine unit.  
  Since cars are responsible for almost a quarter of the world's carbon dioxide emissions, technologists have experimented with alternative power sources developing steam cars, solar-powered cars, and hybrid cars using both electricity (in town centers) and gasoline (on the open road). To achieve weight reduction in the body, aluminum and plastics are being used and fuel consumption is being improved through aerodynamic body designs to reduce air resistance. Microprocessors are also being developed to measure temperature, engine speed, pressure, and oxygen/carbon dioxide content of exhaust gases, and to readjust the engine accordingly.  
  locomotive A locomotive is an engine for hauling railroad trains. In a steam locomotive, fuel (usually coal, sometimes wood) is burned in a furnace. The hot gases and flames produced are drawn through tubes running  
  locomotive The drive of an electric locomotive is provided by powerful electric
motors (traction motors) in the bogies beneath the body of the locomotive.
The motors are controlled by equipment inside the locomotive. Both AC and DC
power supplies are used, although most modern systems use a 2500 V supply.




Page 618
  through a huge water-filled boiler and heat up the water to steam. The steam is then fed to the cylinders, where it forces the pistons back and forth. Movement of the pistons is conveyed to the wheels by cranks and connecting rods. Today most locomotives are diesel or electric.  
  Diesel locomotives have a powerful diesel engine, burning oil, and electric locomotives draw their power from either an overhead cable or a third rail alongside the ordinary track. The engine may drive a generator to produce electricity to power electric motors that turn the wheels, or the engine drives the wheels mechanically or through a hydraulic link. A number of gas-turbine locomotives are in use, in which a turbine spun by hot gases provides the power to drive the wheels.  
  maglev Maglev (an acronym for magnetic levitation) is a high-speed surface transport using the repellent force of superconductive magnets to propel and support, for example, a train above a track. The train is levitated by electromagnets and forward thrust is provided by linear motors aboard the cars, propelling the train along a reaction plate Technical trials on a maglev train track began in Japan in the 1970s, and a speed of 500 kph/310 mph has been reached, with a cruising altitude of 10 cm/4 in.  
  maglev The repulsion of superconducting
magnets and electromagnets in the track
keeps a maglev train suspended above
the track. By varying the strength and
polarity of the track electromagnets,
the train can be driven forward.
  ship A ship is a large seagoing vessel. The invention of the stern rudder during the 12th century, together with the developments made in sailing during the Crusades, enabled the use of sails to almost completely supersede that of oars. One of the finest of the tea clippers, the Sir Launcelot, was built in 1865 and marked the highest development of the sailing ship. Early steamers depended partly on sails for auxiliary power. The opening of the Suez Canal in 1869, together with the simultaneous introduction of the compound engine, raised steamships to superiority over sailing ships. This was followed by the introduction of the internal combustion engine. The tanker was developed after World War II to carry oil supplies to the areas of consumption. The prolonged closure of the Suez Canal after 1967 and the great increase in oil consumption led to the development of the very large tanker, or "supertanker." More recently hovercraft and hydrofoil boats have been developed for specialized purposes, particularly as short-distance ferries. Sailing ships in automated form for cargo purposes, and maglev ships, were in development in the early 1990s.  
port and starboard
  To associate port/starboard, left/right and red/green navigation lights:  
  "There's no red port wine left"  
  (knowing this, you can work out that green, starboard and right go together)  


  hovercraft A hovercraft is a vehicle that rides on a cushion of high-pressure air, free from all contact with the surface beneath, invented by the British engineer Christopher Cockerell in 1959. Hovercraft need a smooth terrain when operating overland and are best adapted to use on waterways. They are useful in places where harbous have not been established.  
  hydrofoil Hydrofoils are wings that develop lift in the water in much the same way that an aeroplane wing develops lift in the air. A hydrofoil boat is a seagoing vessel in which the hull rises out of the water, the boat skimming along the surface due to the lift created by its hydrofoils. The first hydrofoil was fitted to a boat  




Page 619
compass points
  To remember the points of the compass, in the correct order:  
  Nobody ever swallows whales.  
  (Place the first letter of each word in a clockwise circle starting at the 12 o'clock (north) position )  


  in 1906. The first commercial hydrofoil went into operation in 1956.  
  submarine A submarine is an underwater warship. The conventional submarine of World War I was driven by diesel engine on the surface and by battery-powered electric motors underwater. The diesel engine also drove a generator that produced electricity to charge the batteries. In 1954 the USA launched the first nuclear-powered submarine, the Nautilus. Operating depth is usually up to 300 m/1,000 ft, and nuclear-powered speeds of 30 knots (55 kph/34 mph) are reached. As in all nuclear submarines, propulsion is by steam turbine driving a propeller. The steam is raised using the heat given off by the nuclear reactor.  
  U-475: Soviet Foxtrot Class Submarine
  This page provides a room-by-room tour of a Cold War-era Soviet submarine, the U-475. The text is complimented by numerous color photographs of the submarine's interior. Since being sold to a private owner in 1994, the submarine has been moored near London and is open to the public.  
sailing and depth of water
  If sailing in unfamiliar waters, remember:  
  Brown brown, run aground
White white, you might
Green green, nice and clean
Blue blue, run right through
  This allows you to estimate the depth of the water from shallowest to deepest, based on its color  


  airplane Airplanes are powered heavier-than-air craft supported in flight by fixed wings. They are propelled by the thrust of a jet engine or airscrew (propeller). They must be designed aerodynamically, since efficient streamlining prevents the formation of shock waves over the body surface and wings, which would cause instability and power loss. Streamlining the plane also reduces the drag resulting in higher speeds and reduced fuel consumption for a given power. The wing of an airplane has the cross-sectional shape of an airfoil, being broad and curved at the front, flat underneath, curved on top, and tapered to a sharp point at the rear. It is so shaped that air passing above it is speeded up, reducing pressure below atmospheric pressure. This follows from Bernoulli's principle and results in a force acting vertically upward, called lift, which counters the plane's weight.  
  The shape of a plane is dictated principally by the  
  airplane In flight, the forces on an airplane are lift, weight, drag, and thrust.
The lift is generated by the air flow over the wings, which have the shape of an airfoil.
The engine provides the thrust. The drag results from the resistance of the air to the
airplane's passage through it. Various moveable flaps on the wings and tail allow the
airplane to be controlled. The rudder is moved to turn the airplane. The elevators allow
the craft to climb or dive. The ailerons are used to bank the airplane while turning.
The flaps, slats, and spoilers are used to reduce lift and speed during landing.




Page 620
Aviation Firsts
(– = not applicable.)
Date Name Achievement
1804 George Cayley (U.K.) first modern-configuration airplane prototype in history ("Cayley's glider")
1891 Otto Lilienthal (Germany) first successful crewed glider flight
1896 Samuel Pierpont Langley (U.S.A.) first steam-driven pilotless airplane (12,082 m/24,000 ft over the Potomac River)
1903 Orville and Wilbur Wright (U.S.A.) first successful flight of a powered aircraft, Kitty Hawk (NC) (59 seconds; 259 m/850 ft)
1906 Alberto Santos-Dumos (Brazil) first successful European flight (Bagatelle Field, Paris, France)
1908 Frank P Lahm (U.S.A.) first airplane passenger (with Wilbur Smith piloting)
  Samuel Franklin Cody (U.K.) first powered flight in the U.K.
1909 Louis Blériot (France) first successful flight across the English Channel
1910 Raymonde de la Roche (France) first licensed female pilot
  Henri Faber (France) first take-off from water
1911 Harriet Quimby (U.S.A.) first U.S. female pilot
1912 Harriet Quimby (U.S.A.) first crossing of the English Channel by female pilot
  first automatic pilot in service
1913 Ivan Sikorsky (Russia) first multi-engined aircraft
1914 first scheduled passenger airline service (St. Petersburg—Tampa, Florida)
1914–18 first military use of aircraft; developments in speed and power of aircrafts triggered by World War I
1918 first airmail service established in the United States (Washington—New York City)
1919 Walter Hinton (U.S.A.) first transatlantic flight (Trepassy Bay, Newfoundland—Lisbon, Portugal via Horta, Azores, and Ponta Delgada)
  John W Alcock, Arthur Whitten first nonstop transatlantic flight (St John's, Newfoundland—Clifden, Ireland;
  Brown (U.K.) 3,058 km/1,900 mi; 16 hr 12 min)
  Ross Smith, Keith Smith (Australia) first flight from the U.K. to Australia
  first scheduled London, U.K.–Paris, France passenger service
  first airline food served
1923 John A Macready, Oakley Kelly (U.S.A.) first nonstop transcontinental flight (New York—San Diego, U.S.A.; 4,023 km/2,500 mi; 26 hr 50 min)
1924 Lowell Smith, Erik Nelson (U.S.A.) first round-the-world flight
1926 Richard E Byrd, Floyd Bennett (U.S.A.) first flight over the North Pole
1927 Charles Augustus Lindbergh (U.S.A.) first solo nonstop transatlantic flight
1928 Charles K Smith, C T P Ulm first transpacific flight (San Francisco, U.S.A.–Brisbane, Australia)
1929 James H Doolittle (U.S.A.) first take—off and landing relying solely on instruments ("blind")
  Richard E Byrd, Nernt Balchen, first flight over the South Pole
  Harold I June, A C McKinley (U.S.A.)  
1930 Frank Whittle (U.K.) jet engine patented
  Amy Johnson (U.K.) first female pilot to fly from the U.K. to Australia
  Ellen Church (U.S.A.) first flight attendant
1931 Hugh Herndon, Clyde Pangborn (U.S.A.) first nonstop transpacific flight (Sabishiro Beach, Japan—near Wenatchee (W.A.), U.S.A.; 41 hr 13 min)
1932 Amelia Earhart (U.S.A.) first transatlantic solo by a female pilot (Harbor Grace, Newfoundland—Ireland; around 15 hr)
1933 Wiley Post (U.S.A.) first round-the-world solo flight
1937 Amelia Earhart (U.S.A.) first attempt at a round-the-world flight by a female pilot (Earhart disappeared in the Pacific, between New Guinea and Howland Island)
    –first fully pressurized aircraft (Lockheed XC–35)
1939 Erich Warsitz (Germany) first turbojet flight, Germany (Heinkel He 178)
1939–45 developments related to World War II (Hawker Hurricane and Supermarine Spitfire fighters; Avro Lancaster and Boeing Flying Fortress bombers)


  (table continued on next page)  




Page 621
  (table continued from previous page)  
Date Name Achievement
1941 first U.K. jet aircraft (Gloster e.28/39)
1942 Robert Stanley (U.S.A.) first US jet plane flight
1944 first rocket-engine fighter plane operational, Germany (Messerschmitt Me 163B Komet)
1947 Charles E (''Chuck") Yeager (U.S.A.) first piloted supersonic flight (Bell X-1 rocket-powered aircraft)
1949 James Gallagher (U.S.A.) first round-the-world nonstop flight
  first jet airliner in service (de Havilland Comet)
1950 David C Schilling (U.S.A.) first nonstop transatlantic jet flight (U.K. to Limestone, Maine)
1952 first jetliner service (London, U.K.-Johannesburg, South Africa)
1953 first vertical take-off aircraft tested (Rolls-Royce Flying Bedstead)
  Jacqueline Cochran (U.S.A.) first female pilot to break the sound barrier
1957 Archie J Old Jr. (U.S.A.) first nonstop round-the-world jet plane flight (45 hr 19 min)
1958 first domestic jet passenger service (New York-Miami, U.S.A.); first transatlantic jet passenger service (New York, U.S.A.-London, U.K., and Paris, France)
1960 first supersonic bomber (Convair B-58)
1968 first supersonic plane (Tupolev Tu-144; supersonic speed achieved: Mach 2, c. 1,924 kph/1,200 mph)
1970 Mach 2 exceeded (Tupolev Tu-144; 2,140 kph/1,335 mph)
  Boeing 747 jumbo jet in service
1976 first commercial supersonic flights (Concorde)
1977 Paul MacCready (U.S.A.) first succcessful human-powered aircraft (Gossamer Condor)
1979 Bryan Allen (U.S.A.) first crossing of the English Channel by a human-powered aircraft (Gossamer Albatross)
1980 Janice Brown (U.S.A.) first successful long-distance solar-powered flight (Solar Challenger; 10 km/6 mi in 22 min)
1986 Dick Rutan, Jeana Yeager (U.S.A.) first nonstop around-the-world flight without refueling (Voyager; 216 hr 3 min 44 sec)
1988 Kaneilos Kanellopoulos (Greece) first flight of a human-powered aircraft across the Aegean Sea
1992 first radio-controlled ornithopter (aircraft propelled and manoeuvred by flapping wings; model demonstrated in the United States.)
1993 Barbara Harmer (U.K.) first female co-pilot of a commercial supersonic plane
  automatic on-board collision avoidance system (TCAS-2) mandatory in US airspace


  speed at which it will operate. A low-speed plane operating at well below the speed of sound (about 965 kph/600 mph) need not be particularly well streamlined, and it can have its wings broad and projecting at right angles from the fuselage. An aircraft operating close to the speed of sound must be well streamlined and have swept-back wings. Supersonic planes (faster than sound) need to be severely streamlined, and require a needle nose, extremely swept-back wings, and what is often termed a "Coke-bottle" (narrow-waisted) fuselage, in order to pass through the sound barrier without suffering undue disturbance. To give great flexibility of operation at low as well as high speeds, some supersonic planes are designed with variable geometry, or swing wings. For low-speed flight the wings are outstretched; for high-speed flight they are swung close to the fuselage to form an efficient delta wing configuration.  
  Wings by themselves are unstable in flight, and a plane requires a tail to provide stability. The tail comprises a horizontal tailplane and vertical tailfin, called the horizontal and vertical stabilizer respectively. The tail plane has hinged flaps at the rear called elevators to control pitch (attitude). Raising the elevators depresses the tail and inclines the wings upwards (increases the angle of attack). This speeds the airflow above the wings until lift exceeds weight and the plane climbs. However, the steeper attitude increases drag, so more power is needed to maintain speed and the engine throttle must be opened up. Moving the elevators in the opposite direction produces the reverse effect. The angle of attack is reduced, and the plane descends. Speed builds up rapidly if the engine is not throttled back. Turning (changing direction) is effected by moving the rudder hinged to the rear of the tailfin, and by banking (rolling) the plane. It is banked by moving the ailerons, interconnected flaps at the rear of the wings which move in opposite directions, one up, the other down.  




Page 622
  Helicopter Aviation Home Page
  Must for whirlybird fans. Contents include a history of the helicopter, technical aerodynamic details of what keeps them in the air, profile of mechanical components, advice to novice helicopter pilots, and manuals of various kinds of helicopters. There are a great number of images of helicopters.  
  helicopter A helicopter is a powered aircraft that achieves both lift and propulsion by means of a rotary wing, or rotor, on top of the fuselage. It can take off and land vertically, move in any direction, or remain stationary in the air. It can be powered by a piston or jet engine. The rotor of a helicopter has two or more blades of airfoil cross-section like an airplane's wings. Lift and propulsion are achieved by angling the blades as they rotate. A single-rotor helicopter must also have a small tail rotor to counter the torque, or tendency of the body to spin in the opposite direction to the main rotor. Twin-rotor helicopters, like the Boeing Chinook, have their rotors turning in opposite directions to prevent the body from spinning.  
  helicopter The helicopter is controlled by varying the rotor pitch (the angle of
the rotor blade as it moves through the air). For backward flight, the blades in
front of the machine have greater pitch than those behind the craft. This means
that the front blades produce more lift and a backward thrust. For forward flight,
the situation is reversed. In level flight, the blades have unchanging pitch.
  airship, or dirigible Any aircraft that is lighter than air and power-driven is known as an airship or dirigible. It consists of an ellipsoidal balloon that forms the streamlined envelope or hull and has below it the propulsion system (propellers), steering mechanism, and space for crew, passengers, and/or cargo. The balloon section is filled with lighter-than-air gas, either the nonflammable helium or, before helium was industrially available in large enough quantities, the easily ignited and flammable hydrogen. The envelope's form is maintained by internal pressure in the nonrigid (blimp) and semirigid (zeppelin) types. The zeppelin type maintains its form using an internal metal framework.  
  Helicopters of all shapes, sizes, and purposes are shown in photographs on this Web site. Police, military, news, and rescue helicopters are all featured in the hundreds of photographs listed. In addition there is an e-mail forum and many links to other helicopter resources.  
  Technology of Telecommunications  
  Telecommunications is simply communications over a distance, generally by electronic means. The Scottish scientist Alexander Graham Bell pioneered long-distance voice communication in 1876 when he invented the telephone. Today it is possible to communicate internationally by telephone cable or by satellite or  




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  microwave link, with over 100,000 simultaneous conversations and several television channels being carried by the latest satellites.  
  radio Radio is the transmission and reception of radio waves. In radio transmission a microphone converts sound waves (pressure variations in the air) into electromagnetic waves that are then picked up by a receiving aerial and fed to a loudspeaker, which converts them back into sound waves. To carry the transmitted electrical signal, an oscillator produces a carrier wave of high frequency. Different stations are allocated different transmitting carrier frequencies. A modulator superimposes the audiofrequency signal on the carrier. There are two main ways of doing this: amplitude modulation (AM), used for long- and medium-wave broadcasts, in which the strength of the carrier is made to fluctuate in time with the audio signal; and frequency modulation (FM), as used for VHF broadcasts, in which the frequency of the carrier is made to fluctuate. The transmitting aerial emits the modulated electromagnetic waves, which travel outward from it.  
  Biography of G. Marconi
  Presentation of the life and discoveries of Guglielmo Marconi. The site includes sections on his early years and education, and the many patents that he established in the course of his scientific career. Central emphasis is of course given to his development of wireless telegraphy from the first attempt to send a signal one and a half miles away, up to his successful wireless transmission across the Atlantic in 1901.  
  In radio reception a receiving antennae picks up minute voltages in response to the waves sent out by a transmitter. A tuned circuit selects a particular frequency, usually by means of a variable capacitor connected across a coil of wire. A demodulator disentangles the audio signal from the carrier, which is now discarded, having served its purpose. An amplifier boosts the audio signal for feeding to the loudspeaker. In a superheterodyne receiver, the incoming signal is mixed with an internally-generated signal of fixed frequency so that the amplifier circuits can operate near their optimum frequency.  
  telegraphy Telegraphy is the transmission of messages along wires by means of electrical signals. The first modern form of telecommunication, it now uses printers for the transmission and receipt of messages. Telex is an international telegraphy network.  
  fax Fax is the common name for facsimile transmission or telefax, the transmission of images over a telecommunications link, usually the telephone network. When placed on a fax machine, the original image is scanned by a transmitting device and converted into coded signals, which travel via the telephone lines to the receiving fax machine, where an image is created that is a copy of the original. Photographs as well as printed text and drawings can be sent.  
  Mighty Media
  Collaborative site set up by teachers, students and technology advocates. Their aim is to encourage "the use of interactive communication technologies." In essence, they offer support and advice for organizations or groups wanting to make use of the Internet, design their own Web page, etc.  
  telephone Developed by Scottish inventor Alexander Graham Bell in 1876, the telephone is an instrument for communicating by voice along wires. The transmitter (mouthpiece) consists of a carbon microphone, with a diaphragm that vibrates when a person speaks into it. The diaphragm vibrations compress grains of carbon to a greater or lesser extent, altering their resistance to an electric current passing through them. This sets up variable electrical signals, which travel along the telephone lines to the receiver of the person being called. There they cause the magnetism of an electromagnet to vary, making a diaphragm above the electromagnet vibrate and give out sound waves, which mirror those that entered the mouthpiece originally.  
  The standard instrument has a handset, which houses the transmitter (mouthpiece), and receiver (earpiece), resting on a base, which has a dial or pushbutton mechanism for dialing a telephone number. Some telephones combine a push-button mechanism and mouthpiece and earpiece in one unit. A cordless telephone is of this kind, connected to a base unit not by wires but by radio. It can be used at distances up to about 100 m/330 ft from the base unit.  
  Alexander Graham Bell's Path to the Telephone
  Impressive attempt to reconstruct the path towards the invention of the telephone. The presentation aims to communicate the wanderings of Alexander Graham Bell, placing him within the context of other relevant inventions and related ideas. This is achieved mainly through a wealth of graphics retrieved from Bell's experimental notebooks, patents, and other papers accompanied by detailed analysis. An especially worthwhile site for those who are interested in the thought processes behind invention, as well as in the achievement itself.  
  television (TV) Television is the reproduction of visual images at a distance using radio waves. For transmission, a television camera converts the pattern  




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  video camera The heart of the video camera is the vidicon tube which converts light
entering the front lens to an electrical signal. An image is formed on a light-sensitive
surface at the front of the tube. The image is then scanned by an electron beam, to
give an output signal corresponding to the image brightness. The signal is recorded
as a magnetic track traversing the tape diagonally. The sound track, which records
the sounds picked up by the microphone, runs along the edge of the tape.
  of light it takes in, into a pattern of electrical charges. This is scanned line by line by a beam of electrons from an electron gun, resulting in variable electrical signals that represent the picture. These signals are combined with a radio carrier wave and broadcast as electromagnetic waves. The TV antennae picks up the wave and feeds it to the receiver (TV set). This separates out the vision signals, which pass to a cathode-ray tube where a beam of electrons is made to scan across the screen line by line, mirroring the action of the electron gun in the TV camera. The result is a recreation of the pattern of light that entered the camera. In Europe, 25 pictures (30 in North America) are built up each second with interlaced scanning with a total of 625 lines (525 lines in North America and Japan).  
  In color television, signals indicate the amounts of red, green, and blue light to be generated at the receiver. To transmit each of these three signals in the same way as the single brightness signal in black and white television, three times the normal band width would be needed which would reduce the number of possible stations and programs to one-third of that possible with monochrome television. The three signals are therefore coded into one complex signal, which is transmitted as a more or less normal black and white signal and produces a satisfactory—or compatible—picture on black and white receivers. A fraction of each primary red, green, and blue signal is added together to produce the normal brightness, or luminance, signal. The minimum of extra coloring information is then sent by a special subcarrier signal, which is superimposed on the brightness signal. This extra coloring information corresponds to the hue and saturation of the transmitted color, but without any of the fine detail of the picture. The impression of  
  Big Dream, Small Screen
  Companion to the U.S. Public Broadcasting Service (PBS) television programme The American Experience, this page tells the story of Philo Farnsworth, David Sarnoff, and the invention of the television. You will also find an interesting section on TV milestones that features numerous photographs, a list of quotes about television, a biography of David Sarnoff, and a list of sources for further reading.  




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  sharpness is conveyed only by the brightness signal, the coloring being added as a broad color wash. The color receiver has to amplify the complex signal and decode it back to the basic red, green, and blue signals; these primary signals are then applied to a color cathode-ray tube.  
  High-definition television (HDTV) offers a significantly greater number of scanning lines, and therefore a clearer picture, than the 525/625 lines of established television systems. In 1989 the Japanese broadcasting station NHK and a consortium of manufacturers launched the Hi-Vision HDTV system, with 1,125 lines and a wide-screen format. Digital television is a system of transmitting television programs in digital codes. Until the late 1980s it was considered impossible to convert a TV signal into digital code because of the sheer amount of information needed to represent a visual image. However, data compression techniques have been developed to reduce the number of bits that need to be transmitted each second. As a result, digital technology is being developed that will offer sharper pictures on wider screens, and HDTV with image quality comparable to a cinema.  
  telecommunications The international telecommunications system relies on microwave
and satellite links for long-distance international calls Cable links are increasingly made
of optical fibers. The capacity of these links is enormous. The TDRS-C (tracking data and
relay satellite communications) satellite, the world's largest and most complex satellite, can
transmit in a single second the contents of a 20-volume encyclopedia, with each volume
containing 1,200 pages of 2,000 words. A bundle of optical fibers, no thicker than a finger,
can carry 10,000 phone calls–more than a copper wire as thick as an arm.
  Vidkids Media Literacy Program
  Online project initiated by the California Museum of Photography, United States, setting out to give primary schoolchildren an opportunity to learn the technical and creative aspects of video and related media.  
  communications satellites The chief method of relaying long-distance calls on land is microwave radio transmission. This has the drawback that the transmissions follow a straight line from tower to tower, so that over the sea the system becomes impracticable. A system of communications satellites in an orbit 35,900 km/22,300 mi above the Equator, where they circle the earth in exactly 24 hours and thus appear fixed in the sky, is now in operation internationally, by Intelsat. The satellites are called geostationary satellites (syncoms). Telegraphy, telephony, and television transmissions are carried simultaneously by high-frequency radio waves. They are beamed to the satellites from large dish antennae or earth stations, which connect with international networks.  
  Fransworth Chronicles
  Account of the little known story of Philo T. Farnsworth, the "forgotten genius who invented electronic video." First published in 1977, the material displayed in this page was gathered during the 1970s from exhaustive interviews conducted with Farnsworth's widow and eldest son, which were then set against the existing historical records. The site also comprises bonus features on the time before television, Farnsworth's single and intriguing appearance on TV and more.  
  Key Technological Inventions  
  photographic and print technology  
  camera A camera is an apparatus used in photography, consisting of a lens system set in a light-proof box  




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  Technology Timeline
  Companion to the U.S. Public Broadcasting Service (PBS) television programme The American Experience, this page follows the course of technological progress and invention in the United States from the time of Benjamin Franklin's experiments in the 1750s to the creation of the Hubble Telescope in the 1990s. The information is divided into decades along a timeline. Along the way, you can learn about such inventions as the cotton gin, steamboat, revolver, false teeth, passenger elevator, burglar alarm, barbed wire, skyscraper, dishwasher, zipper, frozen food, electric guitar, atomic bomb, optic fiber, video game, bar code, space shuttle, personal computer, and artificial heart.  
  inside of which a sensitized film or plate can be placed. The lens collects rays of light reflected from the subject and brings them together as a sharp image on the film. The opening or hole at the front of the camera, through which light enters, is called an aperture. The aperture size controls the amount of light that can enter. A shutter controls the amount of time light has to affect the film. There are small-, medium-, and large-format cameras; the format refers to the size of recorded image and the dimensions of the image obtained.  
  Cameras: The Technology of Photographic Imaging
  General presentation of the camera collection at the Museum of the History of Science, Oxford, U.K. Of the many highlights perhaps the most distinguished are some very early photographs, the photographic works of Sarah A. Acland, and the cameras of T. E. Lawrence.  
  A simple camera has a fixed shutter speed and aperture, chosen so that on a sunny day the correct amount of light is admitted. More complex cameras allow the shutter speed and aperture to be adjusted; most have a built-in exposure meter to help choose the correct combination of shutter speed and aperture for the ambient conditions and subject matter. The most versatile camera is the single lens reflex (SLR) which allows the lens to be removed and special lenses attached. A pin-hole camera has a small (pin-sized) hole instead of a lens. It must be left on a firm support during exposures, which are up to ten seconds with slow film, two seconds with fast film, and five minutes for paper negatives in daylight. The pin-hole camera gives sharp images from close-up to infinity.  
  Daguerreian Society
  Information about the process involved in this early form of photography, 19th- and 20th-century texts about it, an extensive bibliography of related literature, plenty of daguerreotypes to look at, and information about this society itself can be found here.  
  film, photographic Photographic film is a strip of transparent material (usually cellulose acetate) coated with a light-sensitive emulsion, used in cameras to take pictures. The emulsion contains a mixture of light-sensitive silver halide salts (for example, bromide or iodide) in gelatine. When the emulsion is exposed to  
  camera The single-lens reflex (SLR) camera in which an image can be seen through
the lens before a picture is taken. The reflex mirror directs light entering the lens to
the viewfinder. The SLR allows different lenses, such as close-up or zoom, to be
used because the photographer can see exactly what is being focused on.




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  light, the silver salts are invisibly altered, giving a latent image, which is then made visible by the process of developing. Films differ in their sensitivities to light, this being indicated by their speeds.  
  Color film consists of several layers of emulsion, each of which records a different color in the light falling on it. In color film the front emulsion records blue light, then comes a yellow filter, followed by layers that record green and red light respectively. In the developing process the various images in the layers are dyed yellow, magenta (red), and cyan (blue), respectively. When they are viewed, either as a transparency or as a color print, the colors merge to produce the true color of the original scene photographed.  
  four-color process The four-color process is a color printing process using four printing plates, based on the principle that any color is made up of differing proportions of the primary colors blue, red, and green. The first stage in preparing a color picture for printing is to produce separate films, one each for the blue, red, and green respectively in the picture (color separations). From these separations three printing plates are made, with a fourth plate for black (for shading or outlines and type). Ink colors complementary to those represented on the plates are used for printing—yellow for the blue plate, cyan for the red, and magenta for the green.  
  Timeline of Photography
  Created by the George Eastman International Museum of Photography c0637-01.gifFilm, this page provides a detailed timeline of the history of photography and film, which begins as far back as the 5th century with Aristotle's description of optical principles. You can scroll the timeline or jump to specific periods of interest. Underlined text will take you to more involved descriptions. The bottom of the page contains a list of sources used to create the timeline.  
  halftone process The halftone process is a technique used in printing to reproduce the full range of tones in a photograph or other illustration. The intensity of the printed color is varied from full strength to the lightest shades, even if one color of ink is used. The picture to be reproduced is photographed through a screen ruled with a rectangular mesh of fine lines, which breaks up the tones of the original into areas of dots that vary in frequency according to the intensity of the tone. In the darker areas the dots run together; in the lighter areas they have more space between them. Color pictures are broken down into a pattern of dots in the same way, the original  
  holography Recording a transmission hologram. Light from a laser is divided
into two beams. One beam goes directly to the photographic plate. The other
beam reflects off the object before hitting the photographic plate. The two
beams combine to produce a pattern on the plate which contains information
about the 3-D shape of the object. If the exposed and developed plate is
illuminated by laser light, the pattern can be seen as a 3-D picture of the object.




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  being photographed through a number of color filters. The process is known as color separation. Plates made from the separations are then printed in sequence, yellow, magenta (blue-red), cyan (blue-green), and black, which combine to give the full color range.  
  holography Holography is a method of producing three-dimensional (3-D) images, called holograms, by means of laser light. Holography uses a photographic technique (involving the splitting of a laser beam into two beams) to produce a picture, or hologram, that contains 3-D information about the object photographed. Some holograms show meaningless patterns in ordinary light and produce a 3-D image only when laser light is projected through them, but reflection holograms produce images when ordinary light is reflected from them (as found on credit cards).  
  Holographic techniques have applications in storing dental records, detecting stresses and strains in construction and in retail goods, detecting forged paintings and documents, and producing three-dimensional body scans. The technique of detecting strains is of widespread application. It involves making two different holograms of an object on one plate, the object being stressed between exposures. If the object has distorted during stressing, the hologram will be greatly changed, and the distortion readily apparent.  
  printing Printing is the reproduction of multiple copies of text or illustrative material on paper, as in books or newspapers, or on an increasing variety of materials; for example, on plastic containers. The first printing used woodblocks, followed by carved wood type or molded metal type and hand-operated presses. Modern printing is effected by electronically controlled machinery. Current printing processes include electronic phototypesetting with c0016-01.gifoffset printing, and c0016-01.gifgravure print. Offset printing, prints from an inked flat surface, while the gravure method (used for high-circulation magazines), uses recessed plates.  
  The introduction of electronic phototypesetting machines in the 1960s allowed the entire process of setting and correction to be done in the same way that a typist operates, thus eliminating the hot-metal composing room and leaving only the making of plates and the running of the presses to be done traditionally. By the 1970s some final steps were taken to plateless printing, using various processes, such as a computer-controlled laser beam, or continuous jets of ink acoustically broken up into tiny equal-sized drops, which are electrostatically charged under computer  
  photocopier At the heart of the photocopier is a metal drum on which
an image is formed. The toner is attracted to the image by static electricity.
As the paper moves past the drum, the image is transferred to the paper.
The image is fixed by heating and pressing the toner into the paper.




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  control. Pictures can be fed into computer typesetting systems by optical scanners.  
  lithography Lithography is a printmaking technique invented in 1798 by Aloys Senefelder, based on the mutual repulsion of grease and water. A drawing is made with greasy crayon on an absorbent stone, which is then wetted. The wet stone repels ink (which is greasy) applied to the surface and the crayon absorbs it, so that the drawing can be printed. Lithographic printing is used in book production, posters, and prints, and this basic principle has developed into complex processes.  
  silk-screen printing, or serigraphy Silk-screening is a method of printing based on stenciling. It can be used to print on most surfaces, including paper, plastic, cloth, and wood. An impermeable stencil (either paper or photosensitized gelatine plate) is attached to a finely meshed silk screen that has been stretched on a wooden frame, so that the ink passes through to the area beneath only where an image is required. The design can also be painted directly on the screen with varnish. A series of screens can be used to add successive layers of color to the design.  
  photocopier A photocopier is a machine that uses some form of photographic process to reproduce copies of documents or illustrations. Most modern photocopiers, as pioneered by the Xerox Corporation, use electrostatic photocopying, or xerography ("dry writing"). The Japanese company Ricoh produced a prototype for a "recycle copier" in 1994. It reheats the toner on the paper to 100°C and adds a "peel off" solution to reduce the adhesion of the toner. The paper is then passed through a roller removing all toner. By this method paper can be used up to 10 times.  
  Technology Chronology  
Technology Chronology
c. 2600000 B.C. The first tools, simple pebble choppers, are used in Africa near Lake Rudolph in present-day Kenya. They remain essentially unchanged for the next 1.5 million years.
c. 8000 B.C.
c. 2700
The Mesolithic or Middle Stone Age begins in western Europe. It is characterized by the use of microliths (very small stone tools mounted on a shaft), chipped stone tools, and bone, antler, and wooden tools. Important inventions include the barbed fish-hook, harpoon, woven basket, clay cooking pot, and the comb.
c. 5500 B.C. Copper is smelted in Persia, the first metal to be smelted.
c. 4400 B.C. The weaving loom is invented in Egypt. It consists of a frame that holds two sets of alternating parallel threads in place (the warp). By raising one set of threads it is possible to run a cross-thread (the weft) between them using a shuttle.
c. 3500 B.C. The gnomon—the first clock—is invented, probably in Egypt. It consists of a vertical stick or pillar inserted in the ground, the length of its shadow giving an idea of the time.
c. 3500 B.C. The Sumerians invent the wheel. Consisting of two or three wooden segments held together by transverse struts that rotate on a wooden pole, its invention transforms transportation, warfare, and industry.
c. 3200 B.C. The Bronze Age begins when metallurgists in the Middle East discover that the addition of about 10% tin to copper in the molten state produces bronze. It lasts about 2,000 years.
c. 3000 B.C. Papyrus, derived from reed, is invented in Egypt.
c. 3000 B.C. The abacus, which uses rods and beads for making calculations, is developed in the Middle East and adopted throughout the Mediterranean. A form of the abacus is also used in China at this time.
c. 1700 B.C. Windmills are used in Babylon to pump water for irrigation.
c. 1200 B.C. The Iron Age begins as iron displaces bronze as the most important metal in Egypt and elsewhere.
c. 1100 B.C. The spinning wheel is invented in China, derived from the machines used to draw out silk from the silkworm. It subsequently spreads to India and reaches Europe about the 13th century A.D.
c. 350 B.C. Work begins on Shan-yang Canal in China; it later forms the Southern Grand Canal.
c. 270 B.C. The Greek physicist and inventor Ctesibius of Alexandria lays the foundations for the development of modern pumps with his invention of a small pipe organ, the hydraulis, which is supplied with air by a piston pump.
c. 250 B.C. The Greek mathematician and inventor Archimedes invents the Archimedes screw for removing water from the hold of a large ship. A similar device is already in use in Egypt for irrigation.





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c. 200 B.C. The Romans invent concrete.
850 The earliest Chinese reference to gunpowder, a mixture of saltpeter, sulfur and charcoal, dates to this time. At first, it appears to have been used only for fireworks.
1600 Around this time, the compound microscope, which uses two lenses to magnify objects, is invented—probably by Hans Lippershey or Hans Jansen and his son Zacharias, both spectacle makers from Middelburg in the Netherlands.
1643 The Italian scientist Evangelista Torricelli invents the mercury barometer that records air pressure by the changes in the level of mercury within a glass tube sealed at the top.
1674 The Dutch scientist and instrumentmaker Christiaan Huygens makes a watch using a balance wheel controlled by the oscillations of a spring to keep time.
1679 The French Huguenot refugee Denis Papin makes a "steam digester"—an early form of pressure cooker—for softening bones, and demonstrates it to the Royal Society in England. It uses a safety valve which will find widespread use in the coming industrial revolution.
1712 The first recorded practical steam-engine to use a piston and cylinder, constructed by English inventor Thomas Newcomen, is installed at Dudley Castle, near Wolverhampton, England, where it is used for pumping out underground mineworkings.
1728 The English clockmaker John Harrison completes construction of a clock for measuring longitude at sea, the H-1. After presenting it to English astronomer Edmund Halley and watchmaker George Graham, he makes some adjustments.
1758 The English engineer John Wilkinson installs the first blast furnace at his works in Bilston, Staffordshire, England.
1761 The English engineer James Brindley completes the Duke of Bridgewater's Canal between Manchester and the Worsley collieries in northern England; it is the first British canal of major economic importance.
1764 The English inventor James Hargreaves invents the spinning jenny, which allows one individual to spin several threads simultaneously.
1765 The Scottish inventor James Watt invents a condenser to condense exhaust steam from Newcomen steam engines; it reduces the loss of latent heat, making them more efficient.
1769 The English inventor Richard Arkwright patents a spinning machine (or "water frame" because it operates by water) the produces cotton yarn suitable for warp; it is one of the key inventions of Britain's Industrial Revolution.
1769 The French engineer Nicolas-Joseph Cugnot's steam road carriage carries four people at speeds of 3.6 kph/2.25 mph.
c. 1770 The English inventor Richard Arkwright operates a number of factories using his water-powered spinning machines and in 1773 begins to manufacture calico, establishing textile manufacture as the leading industry in northern England.
1773 T. F. Pritchard's bridge, the first made completely of iron, is completed at Coalbrookdale, Shropshire, England. It is built for the industrialist Abraham Darby.
1775 The Italian physicist Alessandro Volta invents the electrophorus, a device for generating and storing static electricity; it later leads to modern electrical condensers.
1776 The American engineer David Bushnell builds a hand-powered wooden-hulled submarine named the Turtle. It is used in an unsuccessful attempt to attach an explosive device to a British ship.
1779 The English inventor Samuel Crompton devises the spinning mule, a cross between a spinning jenny and a water-frame spinning machine; it makes possible the large-scale manufacture of thread.
1779 The French inventors Jean-Pierre-François Blanchard and M. Masurier construct a velocipede, a type of early bicycle, in Paris, France.
1781 The Scottish engineer James Watt discovers how to convert the up-and-down motion of his steam engine into rotary motion which can then turn a shaft.
1782 James Watt patents the double-acting steam engine, which provides power on both the upstroke and the downstroke of the piston.
1782 The distributing mechanism of English agriculturist Jethro Tull's seed-planting machine is improved with the addition of gears.
1784 Henry Cort discovers the "puddling process" of converting pig iron into wrought iron by stirring to burn off impurities. It revolutionizes the manufacture of iron, production of which quadruples over the next 20 years.
1784 The Swiss inventor Aimé Argand invents an oil-burner consisting of a cylindrical wick, two concentric metal tubes to provide air, and a glass chimney to increase the draught. It gives a light ten times brighter than previous lamps and the principle is later used in gas-burners.
1784 The American engineer Oliver Evans invents an automated process for grinding grain and





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  sifting flour; it marks the beginning of automation in America.
1785 The English inventor Edmund Cartwright develops a steam-powered loom.
1788 The Scottish millwright Andrew Meikle patents a threshing machine for separating the grain from the straw.
1789 The English inventor Edmund Cartwright patents a wool-combing machine.
1794 The English engineer Robert Street patents the first practical internal-combustion engine.
1795 The English inventor Joseph Bramah invents a hydraulic press capable of exerting a force of several thousand tonnes.
1795 The French chef Nicolas Appert begins experiments on preserving food in hermetically sealed container.
1797 The English engineer Henry Maudslay invents the carriage lathe, which permits the operator to use the lathe without holding the metal-cutting tool.
1798 The Frenchman Nicholas-Louis Robert invents a paper-making machine.
1800 The English engineer Henry Maudslay improves his screw-cutting lathe so that it can cut screws of varying pitches.
1800 The Italian physicist Alessandro Volta invents the voltaic pile made of discs of silver and zinc—the first battery.
1800 The U.S. engineer James Finley builds the first suspension bridge in the United States.
Dec 24, 1801 The English engineer Richard Trevithick builds a steam-powered carriage that he successfully drives up a hill in Camborne, Cornwall, England.
1803–1822 The Scottish engineer Thomas Telford constructs the 100 km/60 mi Caledonian Canal, linking Scotland's east and west coasts.
Feb 21, 1804 The English engineer Richard Trevithick builds the first steam railway locomotive, and on a wager runs it on a 16 km/10 mi track at the Pen-y-darren Ironworks in South Wales carrying 10 tons of iron and 70 passengers.
Dec 1, 1804 The English aviation pioner George Cayley develops an instrument to measure wind resistance. About this time he also begins to construct models of gliders with fixed wings, fuselage, elevators and a rudder—the basic configuration of the modern airplane.
1805 The French inventor Joseph-Marie Jacquard develops a loom that uses punched cards to control the weaving of cloth.
1807 The English inventors Henry and Sealy Fourdrinier receive a patent for an improved version of Nicolas-Louis Robert's papermaking machine. Their new ''Fourdrinier machine" allows production of paper in continuous sheets.
1807 The German promoter Frederick Albert Winsor's National Light and Heat Company lights one side of Pall Mall, London, England, with gas lamps—the first street-lighting in the world.
1808 The German artist Ferdinand Piloty produces the first color lithographs.
c. 1812 The Baltimore clipper ship is introduced by U.S. shipbuilders; its revolutionary design—it has a great expanse of sail and hull that offers little water resistance—makes it one of the fastest ships afloat.
1813 The British engineer Bryan Donkin develops a rotary printing press. This is an improvement over the flatbed press, as it allows faster printing, and spurs the development of newspapers.
July 25, 1814 The English engineer George Stephenson constructs the first effective steam locomotive. Called the "Bulcher" it hauls up to 30 metric tons/33 U.S. tons of coal at 6.4 kph/4 mph, out of mines at Killingorth Collier, Newcastle upon Tyne, England.
1815 The English chemist Humphry Davy invents the miner's safety lamp. It does not ignite marsh gas in the mines which causes explosions.
1815 The Scottish inventor John Loudon McAdam begins building roads around Bristol, southwest England. Comprised of two grades of large crushed stone for good drainage and to support the load, and covered by a surface of compacted smaller stones to form a pavement to withstand wear and tear and to shed water to the drainage ditches, they are the most advanced roads built to date.
1816 The French photography pioneer and inventor Joseph-Nicéphore Niépce invents the "celeripede." A two-wheeled ancestor of the bicycle, it is propelled by pushing the feet against the ground, but cannot be steered.
1816 The Scottish clergyman Robert Stirling patents the Stirling hot-air engine. It is powered by the expansion and displacement of air inside an externally heated cylinder. It is forgotten until the Dutch company Philips becomes interested in it in the 1970s.
1821 The English physicist Michael Faraday builds an apparatus that transforms electrical energy into mechanical energy—the principle of the electric motor.
1821 The world's first natural gas well is sunk at Fredonia, New York. Lead pipes distribute the gas to consumers for lighting and cooking.
1822 The U.S. inventor William Church patents the world's first typesetting machine, in Britain.
1824 The English mason Joseph Aspdin patents Portland cement. More water-resistant than other cements, it quickly becomes widely used.
Sept 27, 1825 The Stockton to Darlington railroad line in England opens. Built by George Stephenson, it is the world's first public railroad to carry steam trains. Stephenson's locomotive Active





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  carries 450 passengers at 24 kph/15 mph over the 43 km/27 mi track.
Oct 25, 1825 The canal boat Seneca Chief opens the Erie Canal. Linking the Great Lakes with the Hudson River, it opens the Midwest to settlement.
1825 The U.S. engineer John Stevens constructs the first steam locomotive to run on rails in the United States. It runs on a short circular track at his home in Hoboken, New Jersey.
1825–1843 The English engineer Isambard Kingdom Brunel's Thames Tunnel, the first under a river, is constructed. Its success on opening to pedestrain traffic prompts British solicitor Charles Pearson to propose the construction of a subway system for London, England.
1826 The world's first railroad tunnel is built on the Liverpool–Manchester railway in England.
1827 The English chemist John Walker invents the friction match ("Lucifer"); made with antimony sulfide and potassium chloride it is ignited by drawing it through sandpaper.
Oct 10, 1829– Oct 14, 1829 George and Robert Stephenson's Rocket wins the Liverpool and Manchester Railway competition. Using a multiple fire-tube boiler, rather than the single flue boiler other contestants use, its design sets the pattern for future railroad locomotives.
1830 The French inventor Barthélemy Thimonnier patents the first sewing machines.
1832 The French engineer Benoît Fourneyron develops a water turbine capable of 50 horsepower.
1832 The French inventor Hippolyte Pixü builds the first magneto or magneto-electric generator; it is the first machine to convert mechanical energy into electrical energy.
1832 The U.S. engineer William Avery builds the first practical steam turbine; it is used to power sawmills.
1834 The German chemist Justus von Liebig develops melamine—the basis for synthetic resins such as "Formica" and "Melmac."
1834 The U.S. blacksmith Thomas Davenport constructs the first battery-powered electric motor. He uses it to operate a small car on a short section of track—the first steetcar.
1834 The U.S. inventor Jacob Perkins develops, in Britain, a compression machine that, by alternate compression and expansion of gases freezes water—the beginning of gas refrigeration.
1835 The English scientist William Henry Fox Talbot publishes a paper describing the paper negative. He exposes paper infused with silver chloride to light, which then separates into fine silver and dark tones from which he can take positive prints.
1835 The U.S. manufacturer Samuel Colt patents a six-shot revolver with a rotating cartridge cylinder. Each time the trigger is pulled a new bullet moves in front of the barrel. Its effective range in 23 m/75 ft.
1837 The French artist Louis-Jacques-Mandé Daguerre produces a detailed photograph of his studio on a silvered copper plate.
1837 The French engineer Benoît Fourneyron builds a water turbine which rotates at 2,300 revolutions per minute and generates 60 horsepower. Weighing only 18 kg/40 lb, and with a wheel only 0.3 m/1.0 ft in diameter it is far more productive than the waterwheel and is used to power factories, especially the textile industry, in Europe and the United States.
1837 The German scientist Moritz Hermann von Jacobi, in Russia, develops electroplating; first with silver and then with nickel and chrome.
1839 The British engineer James Nasmyth designs the steam hammer; an important tool for forging heavy machinery in the Industrial Revolution. He patents it on November 24, 1842.
1839 The U.S. inventor Charles Goodyear vulcanizes rubber by adding sulfur and then heating it.
1844 The German engineer Gottlob Keller develops an effective process for making paper from wood pulp, which reduces the cost of newspaper production and helps the growth of mass media.
1845 The English inventor Thomas Wright obtains the first patent for an arc lamp.
1845 The Scottish inventor Robert Thomson patents the pneumatic tire. Although used for 1,931 km/1,200 mi on a horsedrawn brougham carriage, pneumatic tyres are not used again until the end of the century.
Sept 10, 1846 The U.S. inventor Elias Howe patents a practical sewing machine; it revolutionizes garment manufacture in both the factory and home.
1849 The French inventor Eugène Bourdon invents the Bourdon tube, the most commonly used industrial pressure gauge for measuring the pressures of liquids and gases.
May 1, 1851–Sept 18, 1851 The Great Exhibition is held in Hyde Park, London, England. Devised by Prince Albert, it is the first exhibition to display the latest technical innovations in industry, from both Britain and Europe.
Aug 12, 1851 The U.S. inventor Isaac Merrit Singer patents the first practical domestic sewing machine for general use, in Boston, Massachusetts. His design, which enables continuous and curved stitching, and allows any part of the material to be worked on, sets the pattern for all subsequent sewing machines.
1852 The U.S. inventor and machine-shop owner Elisha Otis installs, in a factory in Albany, New York, a freight lift equipped with an





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  automatic safety device that prevents it from falling if the lifting chain or rope breaks.
1854 The French scientist Henri-Etienne St Claire Deville develops a new process for making aluminum. Through the action of metallic sodium on aluminium chloride he produces marble-sized lumps of the metal.
1855 The U.S. manufacturer Samuel Colt opens an armoury at Hartford, Connecticut. Using 1,400 machine tools, he develops the use of interchangeable parts to a high degree and revolutionizes the manufacture of small arms.
1856 The English inventor Henry Bessemer obtains a patent for the Bessemer converter which converts cast iron into steel by injecting air into molten iron to remove carbon and increase the temperature of the molten mass. It allows iron to be poured and thus shaped and brings down prices.
1857 The Scottish-born Australian inventor James Harrison develops a vapor-compression machine using ether as the refrigerant. It is the first to be used in the brewing industry and for freezing meat for shipment.
Jan 31, 1858 The English engineer Isambard Kingdom Brunel's steamship Great Eastern is launched. With a displacement of 19,222 metric tons/18,918 tons, and 211 m/692 ft long, it is the largest ship in the world. It has two sets of engines that drive two screw propellers and two paddlewheels, and is the first steamship with a double iron hull. Its design serves as the prototype for modern ocean liners.
Aug 16, 1858 Queen Victoria of Britain and U.S. president James Buchanan are the first to exchange messages on the first successful Atlantic telegraph cable laid between Valentia, Ireland and Newfoundland, Canada. The cable lasts for only 27 days.
1859 The Belgian inventor (Jean-Joseph-) Etienne Lenoir builds the first internal combustion engine in Paris, France. Operating on coal gas it has only a 4% efficiency.
1861 The Belgian chemist Ernest Solvay patents a method for the economic production of sodium carbonate (washing soda) from sodium chloride, ammonia, and carbon dioxide. Used to make paper, glass, and bleach, and to treat water and refine petroleum, it is a key development in the Industrial Revolution.
1861 The French inventor Pierre Michaux and his son Ernst construct the first successful bicycle with pedals. The pedals are attached to the front wheel, and because it has steel tyres and no springs it is called the "bone-shaker."
1861 The German engineer Nikoluas August Otto constructs an internal combustion engine that runs on gasoline.
1862 The Belgian inventor (Jean-Joseph-) Etienne Lenoir constructs the first car with an internal combustion engine and makes a 10 km/6 mi trip.
1864 The French engineers Pierre and Emile Martin, and British engineer William Siemens, simultaneously develop the open-hearth process for making steel using a regenerative gas-fired furnace. By using hot waste gases to heat the furnace, high quality steel is produced in bulk, and scrap steel can be melted and reused.
1867 The French gardener Joseph Monier patents reinforced concrete by adding steel rods, bars, or mesh to the concrete. It dramatically increases the tensile strength of the concrete, making it capable of sustaining heavy stresses.
1867 The U.S. printer Christopher Latham Sholes constructs the first practical typewriter.
Nov 17, 1869 The French engineer Ferdinand de Lesseps completes the 168 km/105 mi log Suez Canal in Egypt that links the Mediterranean and the Red Sea, and which reduces the route from Europe to Asia by 8,000 km/5,000 mi.
1869 The first chain-driven bicycle is built by the firm of A. Guilmet and Meyer.
1869 The U.S. scientist John Wesley Hyatt, in an effort to find a substitute for the ivory in billiard balls invents (independently of Alexander Parkes) celluloid. The first artificial plastic, it can be produced cheaply in a variety of colors and is resistant to water, oil, and weak acids.
1874 The English inventor H. J. Lawson develops the "safety bicycle." Because it has two equal-sized wheels, rubber tires, and is powered by an endless chain between the pedals and the rear wheel, it has greater stability and in easier to brake than other bicycles.
1875 The Austrian engineer Siegfried Marcus builds one of the first cars powered by gasoline. It is the oldest existing automobile.
1876 The German engineer Karl von Linde develops the first really efficient refrigerator, replacing the potentially explosive methyl ether with ammonia. It opens the way for refrigerated railroad cars and ships.
1876 The German engineer Nikolaus Otto patents the four-stroke internal combustion engine, the prototype of modern engines. Its development marks the beginning of the end of the age of steam. More than 30,000 are built in the following decade.
Dec 18, 1878 The English physicist Joseph Swan demonstrates his electric "glow lamp," in Newcastle, England. It is the first practical carbon-filament incandescent light bulb.
1878 The German-born British inventor Charles Siemens invents the electric arc furnace, the first to use electricity to make steel.
Oct 21, 1879 The U.S. inventor Thomas Edison demonstrates his carbon-filament incandescent lamp light. He lights his Menlo Park power station with





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  30 lamps that burn for two days; later filaments burn for several hundred hours. Each light can be turned on or off separately in the first demonstration of parallel circuit.
1879 The U.S. manufacturer George Eastman invents a machine that applies photographic emulsion to a gelatin plate, which allows him to mass-produce photographic dry-plates.
1883 The English physicist and chemist Joseph Wilson Swan patents a method of creating nitrocellulose (cellulose nitrate) fiber by squeezing it though small holes. It becomes a basic process in the artificial textile industry.
1883 The U.S. architect William Lebaron Jenney completes construction of the ten-story Home Insurance Building in Chicago, Illinois. The world's first true skyscraper, it consists of a steel-girder framework on which the outer covering of masonry hangs. It sparks a boom in the construction of skyscrapers in Chicago.
1884 The German-born U.S. inventor Ottmar Mergenthaler patents the first Linotype typesetting machine. Characters are cast as metal type in complete lines rather than as individual letters as in a monotype machine.
Jan 26, 1885 The German mechanical engineer Karl Friedrich Benz patents a three-wheeled vehicle powered by a two-cycle, single-cylinder internal combustion engine, pioneering the development of the automobile. His car achieves a speed of 14.4 kph/9 mph.
1885 The British inventor John Starley builds the "Rover" safety bicycle. the forerunner of modern bicycles, its wheels are of equal size.
1885 The German mechanical engineers Gottlieb Daimler and Wilhelm Maybach develop a successful lightweight high-speed internal combustion petrol engine, and fit it to a bicycle to create the prototype of the present-day motorcycle.
1885 The U.S. inventor Tolbert Lanston invents the Monotype typesetting machine. Type is cast in individual letters, using a 120-key keyboard.
1886 The English inventor Thomas Crapper invents the modern flush toilet.
1886 The U.S. chemist Charles Martin Hall and French chemist Paul-Louis-Toussaint Héroult, working independently, each develop a method for the production of aluminum by the electrolysis of aluminum oxide. The process reduces the price of the metal dramatically and brings it into widespread use.
Oct 31, 1888 The Scottish veterinary surgeon John Boyd Dunlop patents the pneumatic bicycle tire.
1888 The Serbian-born U.S. inventor Nikola Tesla invents the first alternating current (A.C.) electric motor, which serves as the model for most modern electric motors.
1890 The U.S. inventor and statistician Herman Hollerith uses punched cards to automate counting the U.S. census. The holes, which represent numerical data, are sorted and tabulated by an electric machine, the forerunner of modern computers. In 1896 Hollerith forms the Tabulating Machine Company, which later changes its name to International Business Machines (IBM).
1892 The French chemist Ferdinand-Frédéric Henri Moissan invents the first electric-arc furnace. He uses it to vaporize and fuse different elements and create new materials.
1892 The German engineer Rudolf Diesel patents the diesel engine, a new type of internal combustion engine which runs on a fuel cheaper than gasoline and which, because ignition of the fuel is achieved by compression rather than electric spark, is simpler in construction.
1893 At the World's Columbian Exhibition, at Chicago, Illinois, the U.S. inventor Whitcomb L Judson exhibits a "clasp locker or unlocker for shoes," now known as a zipper.
1893 The German mechanical engineer Karl Friedrich Benz constructs his first four-wheeled car.
1893 The U.S. manufacturer Edward Drummond Libbey produces fabric woven from a mixture of glass fiber and silk, creating the first fiberglass.
1901 The German engineer Carl von Linde separates liquid oxygen from liquid air. It leads to the widespread use of oxygen in industry.
1901 The mass production of cars in Detroit, Michigan, begins when U.S. car manufacturer Ransom Eli Olds produces the three-horsepower Oldsmobile buggy. The first car with a curved dash, it is also the first to be made using assembly line techniques and the first commercially successful car in the United States.
Dec 17, 1903 The U.S. aviator Orville Wright makes the first successful flight in an airplane with a gasoline engine at Kitty Hawk, North Carolina, covering 37 m/120ft in a flight lasting just 12 seconds. During the day, Orville and his brother Wilbur make a number of flights, the longest covering 260 m/852 ft and lasting 59 seconds.
1903 The 16-story Ingalls Building in Cincinnati, Ohio, is completed. It is the first skyscraper built of reinforced concrete.
1906 George Albert Smith of the Charles Urban Trading Co. develops Kinemacolour, the first commercially successful color process for film: it uses two color filters and two reels of film.
Aug 12, 1908 The U.S. car manufacturer Henry Ford of the Ford Motor Company introduces the Model T.





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  Inexpensive (sold for $850), easy to maintain, and mass-produced after 1913, it revolutionizes transportation.
1908 The Belgian-born U.S. chemist Leo H. Baekeland invents the plastic Bakelite: its insulating and malleable properties, combined with the fact that it does not bend when heated, ensures it has many uses.
1912 This Edison film studio produces the first film with sound. It is a 15 minute musical based on nursery rhymes in which the sound is roughly synchronized on a phonograph with the image.
1913 The world's first diesel-electric locomotives begin running in Sweden.
Aug 15, 1914 The Panama Canal opens to traffic. One of the world's greatest engineering feats, it is 81.6 km/50.7 mi long and saves 12,800 km/8,000 mi on the trip around South America. It cost $366,650,000 and around 6,000 workers died during its construction.
1916 A passive form of sonar is developed in the United States and Britain to detect submarines. It consists of a microphone towed behind ships.
1918 The Anti-Submarine Detection Investigation Device (ASDIC) is developed by British and U.S. naval scientists. An active sonar system, it uses the echo of a pulsed sound to detect submarines.
1920 The U.S. inventor James Smathers pioneers the electric typewriter as an office machine.
Mar 16, 1926 The U.S. inventor Robert Hutchings Goddard achieves the first flight of a liquid-propelled rocket, at Auburn, Michigan. It reaches an altitude of 12 m/41 ft.
1926 The U.S. research company Bell Laboratories issues the first synchronous sound motion picture system.
1928 Polyvinyl chloride (PVC) is developed, simultaneously, by the U.S. companies Carbide and Carbon Corporation and Du Pont and the German firm I. G. Farben.
1930 The English inventor Frank Whittle patents a turbo-jet engine. It is later used on the first jet airplane.
1932 Pioneering radar equipment at the U.S. Naval Research Laboratory is able to detect aircraft 80 km/50 mi away from its transmitter, but unable to locate them.
April 1936 U.S. scientists produce a workable radar with a range of 4 km/2.5 mi. By the end of the year this is extended to 11 km/7 mi.
Nov 2, 1936 The British Broadcasting Corporation (BBC) starts the world's first public high-definition television service from its transmitter at Alexandra Palace, London, England, using Logie Baird's mechanical system and EMI's electronic system.
April 12, 1937 The English engineer Frank Whittle tests the first prototype jet engine. A similar engine is developed in Germany at the same time.
May 27, 1937 The Golden Gate Bridge in San Francisco, California, opens; it is the longest suspension bridge to date at 1,965 m/6,450 ft.
1937 Nylon, developed by W. H. Carothers, is patented by the U.S. chemicals company Du Pont and is commercially available the following year in the form of toothbrush bristles; nylon stockings become widely available in the United States in May 1940.
Oct 22, 1938 In the United States, Chester Carlson produces the first example of xerography ("dry writing"), which is to develop into modern photocopying.
Aug 27, 1939 The Heinkel He 178 makes a test flight in Germany, achieving a speed of 500 kph/360 mph; it is the first jet airplane to fly.
Oct 3, 1942 The V2 rocket, the ancestor of modern space rockets, is first launched, in Germany; weighing 40 tons it is 12 m/40 ft long, burns an alcohol-liquid oxygen mixture, can reach a distance of 200 km/125 mi, a height of 97 km/60 mi, and travels at 5,300kph/3,300 mph.
1943 The French oceanographer Jacques Cousteau invents the aqualung (or self-contained underwater breathing apparatus, "scuba"), the first fully automatic compressed-air breathing apparatus. It allows him to dive to a depth of 64 m/210 ft.
Oct 8, 1945 In Waltham, Massachusetts, United States, Percy LeBaron Spencer patents the first microwave, which is used is restaurants and institutions.
1948 The first atomic clock is installed at the National Bureau of Standards, Washington, D.C.; it is based on the oscillation of the ammonia molecule and operates using the natural vibrations of atoms. It is extremely accurate, with an error margin of 2 seconds in every 2 million years.
1948 The U.S. physicists John Bardeen, William Bradley Shockley, and Walter Brattain develop the transistor in research at Bell Telephone Laboratories in the United States.
1949 The Swiss engineer Georges de Mestral invents velcro after getting the idea form the burs that stick to his socks. The name is formed from the first letters of velvet and crochet.
1949 The Intertype Fotosetter Photographic Line Composing Machine is introduced in the USA; it is the first typesetting machine that does not use metal type.
1950 The first Xerox photocopying machine is produced by the Haloid Company (later to become the Xerox Corporation) in Rochester, New York.
1952 A method of converting iron to steel, known as the basic—oxygen process, is developed in Linz and Donawitz, Austria. By blowing a supersonic jet of oxygen over the surface of the molten material the nitrogen content is reduced, producing a better quality steel. It replaces the Bessemer process.





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1954 The silicon transistor is developed by Texas Instruments engineer Gordon Teal. Cheaper and more resistant to higher temperatures than germanium, the development of silicon transistors stimulates the growth of solid state components in computers, airplanes, and missiles.
Sept 12, 1955 The English engineer Christopher Cockerell patents the first hovercraft.
1956 The German engineer Felix Wankel invents the Wankel engine, an internal combustion engine that uses a triangular-shaped rotor instead of pistons.
1959 The U.S. engineer Jean Hoerni of Fairchild Semiconductor Corporation designs the planar or "flat" transistor and U.S. engineer Robert Noyce discovers a way to join the circuits by printing, eliminating hundreds of hours in their production. Their work leads to the creation of the first microchip, which stimulates the computer industry with its sharply reduced size and cost and leads to the third generation of computers.
1960 The halogen lamp is introduced. The halogen gas in the lamp regenerates the filament, permitting it to burn at higher temperatures, and thus burn brighter.
1961 The U.S. inventor George Devol and U.S. businessman Joseph Engelberger develop the first true robot, a programmable manipulator called "Programmed Article Transfer." Installed at General Motors by their company Unimation, it is used to unload parts from a die-casting operation.
1963 The U.S. chemist Leslie Phillips and colleagues at the Royal Aircraft Establishment, Farnborough, develop carbon fiber. It is used for strength in bridges and turbine blades.
1964 Xerox develops the first office fax in the United States. It can only operate on dedicated phone lines.
1965 The Japanese electronic company Sony launches the Sony CV-2000, the first home video recorder, using Sony's Betamax format. The first color video recorder is available the following year.
1970 Canon Business Machines markets the first pocket calculator, in Japan.
1970 the U.S. scientist Charles Burns invents the light-emitting diode (LED).
1972 The English engineer Godfrey Hounsfield performs the first successful CAT (computerized axial tomography) scan, which provides cross-sectional X-rays of the human body.
1972 The Japanese researcher Hideki Shirakawa attempts to make the polymer polyacetylene but accidentally adds a thousand times too much catalyst and discovers electrically conductive plastics; they have a metallic appearance.
1973 The U.S. chemist and medical information scientist Paul Lauterbur obtains the first NMR (nuclear magnetic resonance) image, in Britain. Radio waves are beamed through a patient's body white subjected to a powerful magnetic field; an image is generated because different atoms absorb radio waves at different frequencies under the influence of a magnetic field.
1975 Liquid crystals are first used for display purposes in electronic devices such as watches and calculators.
Jan 21, 1976 Two Concorde aircraft make their first commercial flights, from London, England, to Bahrain and from Paris, France, to Rio de Janeiro, Brazil.
1976 The home videocassette recorder is introduced into the U.S. market, with two incompatible models. The Japanese electronics company Sony markets the Betamax system, released in 1975, and fellow Japanese electronics company Japanese Matsushita Corporation JVC) markets the Video Home System (or VHS), which eventually dominates the trade.
1979 The Dutch company Philips and the Japanese company Sony work collaboratively to develop the compact disk (CD); tiny pits on the plastic are read by laser to reproduce sound or other information. CDs are first marketed in 1982.





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Sept 22, 1981 French railroads introduce The TGV (train à grande vitesse, "high-speed train"); electrically powered and capable of cruising at 290 kph/180 mph, it is Europe's first super high speed passenger train. Later in the year achieves a record speed of 380 kph/236 mph.
Oct 1982 The Japanese company Sony launches the first compact disc (CD) players in Japan, working with Philips, the Dutch manufacturer of the compact disc.
April 1986 The first large plant to irradiate food is set up in New Jersey, United States, to process fruits and vegetables arriving from tropical countries; other plants soon open in the Netherlands, Japan, Canada, and other countries.
1986 The first digital audio tape (DAT) recorders are demonstrated in Japan.
1986 The M25, the world's longest beltway at 195 km/121 mi, is completed around London, England,
Feb 12, 1987 The Chinese physicist Paul Ching-Wu Chu and associates at the University of Huston, Texas, United States, make a material that is superconducting at the temperature of liquid nitrogen—77K or –196°C/–321°F.
1987 The Japanese firm Nippon Zeon discovers memory plastic—plastic that change their shape at one temperature and then return to their original shape at another. Applications are envisioned in the auto industry.
1988 Fujitsu laboratories in Japan develop monocrystalline superconductors—crystal superconductors only one layer of crystal thick. They retain heat better than several layers and thus allow the construction of large integrated circuits with little energy loss and unequalled speed.
1988 Researchers at IBM's Almaden Research Center in San José, California, using a scanning tunneling microscope, produce the first image of the ring structure of benzene, the simplest aromatic hydrocarbon.
1988 The Seikan Tunnel under Tsugaru Strait between Honshu and Hokkaido islands, Japan, is completed; 54 km/86.9 mi long, it is the longest undersea railroad tunnel in the world.
Dec 1, 1990 British and French tunneling engineers, working from opposite sides of the English Channel to build the Channel Tunnel, break through the last few yards of ground separating their excavations.
1991 Several U.S. companies introduce local area networks (LANs), which use nondirectional microwaves to transmit data as fast as fiber optic cables.
1992 The electronics companies Matsushita and Philips launch the Digital Compact Cassette.
1993 French and Russian chemists create a superhard material by crystallizing buckminsterfullerenes at very high pressure. The material is able to scratch diamond.
June 1994 The Dutch electronics company Philips launches films on digital video disk, using technology developed jointly by Philips and Japanese electronics company Sony.
July 2, 1996 The U.S. aerospace company Lockheed Martin unveils plans for the X-33, a $1-billion wedge-shaped rocket ship. Called the Venture Star, it will be built and operated by Lockheed Martin and will replace the U.S. space shuttle fleet by the year 2012.
July 1996 The U.S. engineers Theodore O. Poehler and Peter C. Searson announce the invention of the first all-plastic battery. It uses polymers instead of conventional electrode materials and has implications for military and space applications as well as its use in consumer devices such as hearing aids and wristwatches.
Dec 5, 1996 General Motors launches the Saturn EV1 in California and Arizona: the first mass-market electric car.
1997 A credit card-sized version of the plastic battery is introduced by its U.S. inventors in Baltimore, Maryland. It produces 2.5 volts of electricity.
April 5, 1998 The world's largest suspension bridge, linking Kobe and Awaji Island in Japan, opens to traffic. It costs £2.2 billion and is 3.9 km/2.4 mi long.





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  Arkwright, Richard (1732–1792) English inventor and manufacturing pioneer who, in 1768, developed a machine for spinning cotton, called a "water frame," which was the first machine capable of producing sufficiently strong cotton thread to be used as warp. In 1773 Arkwright produced the yarn "water twist," the first cloth made entirely from cotton; previously, the warp had been of linen and only the weft was cotton.  
  Baird, John Logie (1888–1946) Scottish electrical engineer who pioneered television. In 1925 he gave the first public demonstration of television, transmitting an image of a recognizable human face. Baird used a mechanical scanner which temporarily changed an image into a sequence of electronic signals that could then be reconstructed on a screen as a pattern of half-tones. His first pictures were formed of only 30 lines repeated approximately 10 times a second. The following year, he gave the world's first demonstration of true television before an audience of about 50 scientists at the Royal Institution, London. By 1928 Baird had succeeded in demonstrating color television.  
  Bell, Alexander Graham (1847–1922) Scottish-born U.S. scientist and inventor. He was the first person ever to transmit speech from one point to another by electrical means. This invention—the telephone—was made in 1876. Later, Bell experimented with aeronautics. Bell also invented a type of phonograph, the tricycle undercarriage, and the photophone, which used selenium crystals to apply the telephone principle to transmitting words in a beam of light. He thus achieved the first wireless transmission of speech.  
  Benz, Karl Friedrich (1844–1929) German automobile engineer. He produced the world's first gasoline-driven motor vehicle. He produced a two-stroke engine of his own design in 1878, and in 1885, the first vehicle successfully propelled by an internal-combustion engine. It achieved a speed of up to 5 kph/3 mph. The production model Tri-car appeared 1886–87 and had a 1 kW/1.5 hp single-cylinder engine. Benz made his first four-wheeled prototype in 1891 and by 1895, he was building a range of four-wheeled vehicles that were light, strong, inexpensive, and simple to operate. These vehicles ran at speeds of about 24 kph/15 mph.  
  Bessemer, Henry (1813–1898) British engineer and inventor who developed a method of converting molten pig iron into steel (the Bessemer processer) in 1856. By modifying the standard process, he found a way to produce steel without an intermediate wrought-iron stage, reducing its cost dramatically. However, to obtain high-quality steel, phosphorus-free ore was required. In 1860 Bessemer erected his own steelworks in Sheffield, importing phosphorus-free iron ore from Sweden.  
  Biró, Lazlo Hungarian-born Argentine who invented a ballpoint pen in 1944. His name became generic for ballpoint pens in the UK.  
  Bridgewater, Francis Egerton, 3rd Duke of Bridgewater (1736–1803) Pioneer of British inland navigation. With James Brindley as his engineer, he constructed 1762–72 the Bridgewater Canal from Worsley to Manchester and on to the Mersey, a distance of 67.5 km/42 mi. Initially built to carry coal, the canal crosses the Irwell Valley on an aque-duct.  
  Brunel, Isambard Kingdom (1806–1859) British engineer and inventor. The son of Marc Brunel, he made major contributions in shipbuilding and bridge construction, and assisted his father in the Thames tunnel project. He built the Clifton Suspension Bridge over the River Avon at Bristol and the Saltash Bridge over the River Tamar near Plymouth. His shipbuilding designs include the Great Western (1837), the first steamship to cross the Atlantic regularly, and the Great Britain (1843), the first large iron ship to have a screw propeller. Brunel's last ship, the Great Eastern (1858), was to remain the largest ship in service until the end of the 19th century. With over ten times the tonnage of his first ship, it was the first ship to be built with a double iron hull, was driven by both paddles and a screw propeller, and laid the first transatlantic telegraph cable.  
  Brunel, Marc Isambard (1769–1849) French-born British engineer and inventor, father of Isambard Kingdom Brunel. In 1799 he moved to England to mass-produce marine blocks, which were needed by the navy. Brunel demonstrated that with specially designed machine tools 10 men could do the work of 100, more quickly, more cheaply, and yield a better product. He constructed the tunnel under the River Thames in London from Wapping to Rotherhithe 1825–43.  
  Cartwright, Edmund (1743–1823) British inventor. He patented the water-driven power loom in 1785, built a weaving mill in 1787, and patented a wool-combing machine in 1789 which did the work of 20 hand-combers.  
  Cockerell, Christopher Sydney (1910– ) English engineer who invented the hovercraft in the 1950s.  
  Crompton, Samuel (1753–1827) British inventor. He invented the "spinning mule" in 1779. Called the mule because it combined the ideas of Richard c0016-01.gifArkwright's water frame and James c0016-01.gifHargreaves's spinning jenny, it spun a fine, continuous yarn and revolutionized the production of high-quality cotton textiles.  
  Cugnot, Nicolas-Joseph (1725–1804) French engineer who produced the first high-pressure steam engine and, in 1769, the first self-propelled road vehicle. The three-wheeled, highpressure carriage was capable of carrying 1,800 liters/400 gallons of water and four passengers at a speed of 5 kph/3 mph. Although it proved the viability of steam-powered traction, the problems of water supply and pressure maintenance severely handicapped the vehicle.  
  Daguerre, Louis Jacques Mandé (1787–1851) French pioneer of photography. Together with his fellow French pioneer Joseph-Nicéphore Niépce (1765–1833), he is credited with the invention of photography (though others were reaching the same point simultaneously). In 1838 he invented the daguerreotype, a single image process superseded ten years later by Fox c0016-01.gifTalbot's negative/positive process.  
  Daimler, Gottlieb Wilhelm (1834–1900) German engineer who pioneered the car and the internal-combustion engine  




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  together with Wilhelm Maybach. In 1885 he produced a motor bicycle and in 1889 his first four-wheeled motor vehicle. He combined the vaporization of fuel with the high-speed four-stroke gasoline engine.  
  De Havilland, Geoffrey (1882–1965) British aircraft designer who designed and whose company produced the Moth biplane, the Mosquito fighter-bomber of World War II, and in 1949 the Comet, the world's first jet-driven airliner to enter commercial service.  
  Diesel, Rudolf Christian Karl (1858–1913) German engineer who patented the diesel engine. He began his career as a refrigerator engineer and, like many engineers of the period, sought to develop a better power source than the conventional steam engine. Able to operate with greater efficiency and economy, the diesel engine soon found a ready market.  
  Dunlop, John Boyd (1840–1921) Scottish inventor who founded the rubber company that bears his name. In 1888, to help his child win a tricycle race, he bound an inflated rubber hose to the wheels. The same year he developed commercially practical pneumatic tires, first patented by Robert William Thomson (1822–1873) in 1845 for bicycles and cars. Dunlop's first simple design consisted of a rubber inner tube, covered by a jacket of linen tape with an outer tread also of rubber. The inner tube was inflated using a football pump and the tire was attached by flaps in the jacket which were rubber-cemented to the wheel. Later, he incorporated a wire through the edge of the tire which secured it to the rim of the wheel.  
  Eastman, George (1854–1932) U.S. entrepreneur and inventor who founded the Eastman Kodak photographic company in 1892. He patented flexible film in 1884, invented the Kodak box camera in 1888, and followed this up in 1889 with the first commercially available transparent nitrocellulose (celluloid) roll films. He introduced daylight-loading film in 1892. By 1900 his company was selling a pocket camera for as little as one dollar ushering in the era of press-button photography.  
  Edison, Thomas Alva (1847–1931) U.S. scientist and inventor, whose work in the fields of communications and electrical power greatly influenced the world in which we live. His first invention was an automatic repeater for telegraphic messages. He then invented a tape machine called a "ticker," which communicated stock exchange prices across the country. Edison improved Bell and Gray's telephone with his invention of the carbon transmitter, which so increased the volume of the telephone signal that it was used as a microphone in the Bell telephone. In 1877 he launched the era of recorded sound by inventing the phonograph, a device in which the vibrations of the human voice were engraved by a needle on a revolving cylinder coated with tin foil. In 1879, using carbonized sewing cotton mounted on an electrode in a vacuum (one millionth of an atmosphere), he invented the electric light bulb. He also constructed a system of electric power distribution for consumers, the telephone transmitter, the megaphone, and the kinetoscopic camera, an early movie camera. With more than 1,000 patents, Edison produced his most important inventions in Menlo Park, New Jersey, between 1876 and 1887.  
  Ford, Henry (1863–1947) U.S. automobile manufacturer. He built his first car in 1896 and founded the Ford Motor Company in 1903. His Model T (1908–27) was the first car to be constructed solely by assembly-line methods and to be mass-marketed; 15 million of these cars were sold. In 1928 he launched the Model A, a stepped-up version of the Model T.  
  Giffard, Henri (1825–1882) French inventor of the first passenger-carrying powered and steerable airship, called a dirigible, built in 1852. The hydrogen-filled airship was 43 m/144 ft long, had a 2,200-W/3-hp steam engine that drove a three-bladed propeller, and was steered using a sail-like rudder. It flew at an average speed of 5 kph/3 mph.  
  Goddard, Robert Hutchings (1882–1945) U.S. rocket pioneer. He developed the principle of combining liquid fuels in a rocket motor, the technique used subsequently in every practical space vehicle. His first liquid-fuelled rocket was launched at Auburn, Massachusetts, in 1926. In 1929, instruments, and a camera to record them, were carried aloft for the first time, and by 1935 his rockets had gyroscopic control. Two years later a Goddard rocket gained the world altitude record with an ascent of 3 km/1.9 mi. He was the first to prove by actual test that a rocket will work in a vacuum and he was the first to fire a rocket faster than the speed of sound.  
  Goodyear, Charles (1800–1860) U.S. inventor who developed rubber coating in 1837 and vulcanized rubber in 1839, a method of curing raw rubber to make it strong and elastic.  
  Gutenberg, Johannes (Gensfleisch) (c. 1398–1468) German printer, the inventor of printing from movable metal type based on the Chinese wood-block-type method. Gutenberg began work on the process in the 1440s and in 1450 set up a printing business in Mainz. By 1456 he had produced the first printed Bible (known as the Gutenberg Bible). He punched and engraved a steel character (letter shape) into a piece of copper to form a mold that he filled with molten metal.  
  Hargreaves, James (c. 1720–1778) English inventor who coinvented a carding machine for combing wool in 1760. About 1764 he invented the "spinning jenny" (patented in 1770), which enabled a number of threads to be spun simultaneously by one person. The spinning jenny multiplied eightfold the output of the spinner and could be worked easily by children.  
  Hooke, Robert (1635–1703) English scientist and inventor, originator of Hooke's law. His inventions included a telegraph system, the spirit level, marine barometer, and sea gauge. He coined the term "cell" in biology. He studied elasticity, furthered the sciences of mechanics and microscopy, invented the hairspring regulator in timepieces, perfected the air pump, and helped improve such scientific instruments as microscopes, telescopes, and barometers. His work on gravitation and in optics contributed to the achievements of his contemporary the English physicist and mathematician Isaac Newton.  
  Jacquard, Joseph Marie (1752–1834) French textile manufacturer. He invented a punched-card system for programming designs on a carpet-making loom. In 1801 he constructed looms that used a series of punched cards to control the pattern of longitudinal warp threads depressed before each sideways passage of the shuttle. On later machines the  




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  punched cards were joined to form an endless loop that represented the "program" for the repeating pattern of a carpet. Jacquard-style punched cards were used in the early computers of the 1940s–1960s.  
  Lesseps, Ferdinand Marie, Vicomte de Lesseps (1805–1894) French engineer. He designed and built the Suez Canal 1859–69, shortening the route between Britain and India by 9,700 km/6,000 mi. He began work on the Panama Canal in 1881, but withdrew after failing to construct it without locks.  
  Lilienthal, Otto (1848–1896) German aviation pioneer who inspired the U.S. aviators Orville and Wilbur Wright (see c0016-01.gifWright brothers). Lilienthal demonstrated the superiority of cambered wings over flat wings—the principle of the airfoil and from 1891 he made and successfully flew many gliders, including two biplanes. In his planes the pilot was suspended by the arms, as in a modern hang-glider. He achieved glides of more than 300 m/1,000 ft.  
  Lumière, Auguste Marie Louis Nicolas (1862–1954) and Louis Jean (1864–1948) French brothers who pioneered cinematography. In February 1895 they patented their cinematograph, a combined camera and projector operating at 16 frames per second, screening short films for the first time on March 22, and in December opening the world's first movie theater in Paris.  
  McAdam, John Loudon (1756–1836) Scottish engineer, inventor of the macadam road surface. McAdam introduced a method of road building that raised the road above the surrounding terrain, compounding a surface of small stones bound with gravel on a firm base of large stones. A camber, making the road slightly convex in section, ensured that rainwater rapidly drained off the road and did not penetrate the foundation. It originally consisted of broken granite bound together with slag or gravel, raised for drainage. Today, it is bound with tar or asphalt.  
  Marconi, Guglielmo (1874–1937) Italian electrical engineer and pioneer in the invention and development of radio. In 1895 he achieved radio communication over more than a mile. In 1898 he successfully transmitted signals across the English Channel, and in 1901 established communication with St. John's, Newfoundland, from Poldhu in Cornwall, and in 1918 with Australia. Marconi's later inventions included the magnetic detector (1902), horizontal direction telegraphy (1905), and the continuous wave system (1912).  
  Montgolfier, Joseph Michel (1740–1810) and Jacques Etienne (1745–1799) French brothers whose hot-air balloon was used for the first successful human flight on November 21, 1783. The Montgolfier experiments greatly stimulated scientific interest in aviation.  
  Morse, Samuel Finley Breese (1791–1872) U.S. inventor. In 1835 he produced the first adequate electric telegraph. The signal current was sent in an intermittent coded pattern and would cause an electromagnet to attract intermittently to the same pattern on a piece of soft iron to which a pencil or pen would be attached and which in turn would make marks on a moving strip of paper. In 1843 he was granted $30,000 by Congress for an experimental line between Washington, D.C., and Baltimore. With his assistant Alexander Bain (1810–1877) he invented the Morse code.  
  Muybridge, Eadweard (1830–1904) Adopted name of Edward James Muggeridge, English-born U.S. photographer. He made a series of animal locomotion photographs in the United States in the 1870s and proved that, when a horse trots, there are times when all its feet are off the ground. He also explored motion in birds and humans.  
  Otis, Elisha Graves (1811–1861) U.S. engineer who developed a lift that incorporated a safety device, making it acceptable for passenger use in the first skyscrapers. The device, invented in 1852, consisted of vertical ratchets on the sides of the lift shaft into which spring-loaded catches would engage and lock the lift in position in the event of cable failure. In 1857 the first public passenger lift was installed in New York. Otis also invented and patented railroad trucks and brakes, a steam plow, and a baking oven.  
  Remington, Philo (1816–1889) U.S. inventor. He designed the breech-loading rifle that bears his name. He began manufacturing typewriters in 1873, using the patent of the U.S. printer and newspaper editor Christopher Sholes (1819–1890), and made improvements that resulted five years later in the first machine with a shift key, thus providing lower-case letters as well as capital letters.  
  Sikorsky, Igor Ivan (1889–1972) Ukrainian-born U.S. engineer. He built the first successful helicopter in 1939 (commercially produced from 1943). His first biplane flew in 1910, and in 1929 he began to construct multi-engined flying boats.  
  Singer, Isaac Merrit (1811–1875) U.S. inventor of domestic and industrial sewing machines. Within a few years of opening his first factory in 1851, he became the world's largest sewing-machine manufacturer and by the late 1860s more than 100,000 Singer sewing machines were in use in the United States alone. Singer used the best of the U.S. inventor Elias Howe's sewing machine design and altered some of the other features. The basic mechanism was the same: as the handle turned, the needle paused at a certain point in its stroke so that the shuttle could pass through the loop formed in the cotton. When the needle continued, the threads were tightened, forming a secure stitch.  
  Stephenson, George (1781–1848) English engineer who built the first successful steam locomotive. He introduced a system by which exhaust steam was redirected into the chimney through a blast pipe, bringing in air with it and increasing the draft through the fire. This development made the locomotive truly practical. He also invented a safety lamp independently of the English chemist Humphrey Davy in 1815. In 1821 he was appointed engineer of the Stockton and Darlington Railway, the world's first public railroad, setting the gauge at 1.4 m/4 ft 8 in, which became the standard gauge for railroads in most of the world. In 1829 he won a prize with his locomotive Rocket. He also advocated the use of malleable iron rails instead of cast iron.  
  Stephenson, Robert (1803–1859) English civil engineer. He constructed railroad bridges such as the high-level bridge at Newcastle-upon-Tyne, England, and the Menai and Conway tubular bridges in Wales. He was the son of George Stephenson. The successful Rocket steam locomotive was built under his direction in 1829, as were subsequent improvements to it.  




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  Swan, Joseph Wilson (1828–1914) English inventor. Swan invented an incandescent-filament electric lamp using a filament of cotton thread partly dissolved by sulfuric acid. He patented the process in 1880 and began manufacturing lamps. He also developed bromide paper for use in developing photographs, and a miner's electric safety lamp, which was the ancestor of the modern miner's lamp, and in the course of this invention he devised a new lead cell (battery) which would not spill acid. He also attempted to make an early type of fuel cell.  
  Talbot, William Henry Fox (1800–1877) English pioneer of photography. In 1841 he invented the paper-based calotype process—the first negative/positive method. Writing paper was coated successively with solutions of silver nitrate and potassium iodide, forming silver iodide. The iodized paper was made more sensitive by brushing with solutions of gallic acid and silver nitrate, and then it was exposed (either moist or dry). The latent image was developed with an application of gallo-silver nitrate solution, and when the image became visible, the paper was warmed for one to two minutes. It was fixed with a solution of potassium bromide (later replaced by sodium hyposulfite). Calotypes did not have the sharp definition of daguerreotypes and were generally considered inferior. Talbot made photograms several years before Louis c0016-01.gifDaguerre's invention was announced. In 1851 he made instantaneous photographs by electric light and in 1852 photo engravings. The Pencil of Nature (1844–46) by Talbot was the first book illustrated with photographs to be published.  
  Telford, Thomas (1757–1834) Scottish civil engineer. He opened up northern Scotland by building roads and waterways. He constructed many aqueducts and canals, including the Caledonian Canal (1802–23), and erected the Menai road suspension bridge between Wales and Anglesey (1819–26), a type of structure scarcely tried previously in the U.K. In Scotland he constructed over 1,600 km/1,000 mi of road and 1,200 bridges, churches, and harbors.  
  Tesla, Nikola (1856–1943) Serbian-born U.S. physicist and electrical engineer who invented fluorescent lighting, the Tesla induction motor (1882–87), and the Tesla coil, and developed the alternating current (AC) electrical supply system.  
  Trevithick, Richard (1771–1833) English engineer, constructor of a steam road locomotive, the Puffing Devil, in 1801. By 1804 he had produced the first railroad locomotive to run on rails and the first to carry passengers. Able to haul 10 tonnes and 70 people for 15 km/9.5 mi it was set up on rails used by horse-drawn trains at a mine in Wales.  
  von Braun, Wernher Magnus Maximilian (1912–1977) German rocket engineer responsible for Germany's rocket development program in World War II (V1 and V2). He later worked for the space agency NASA in the United States. He also invented the Saturn rocket (Saturn V) that sent the Apollo spacecraft to the moon in 1969.  
  Watt, James (1736–1819) Scottish engineer who developed the steam engine in the 1760s, making the English inventor Thomas Newcomen's earlier engine vastly more efficient by cooling the used steam in a condenser separate from the main cylinder. He eventually made a double-acting machine that supplied power with both directions of the piston and developed rotary motion. During the period 1775–90, Watt invented an automatic centrifugal governor, which cut off the steam when the engine began to work too quickly and turned it on again when it had slowed sufficiently. He also devised a steam engine indicator that showed steam pressure and the degree of vacuum within the cylinder. Watt devised a rational method to rate the capability of his engines by considering the rate at which horses worked. After many experiments, he concluded that a ''horsepower" was 33,000 lb (15,000 kg raised through 1 ft (0.3 m) each minute. The modern unit of power, the watt, is named for him.  
  Westinghouse, George (1846–1914) U.S. inventor and founder of the Westinghouse Corporation in 1886. Westinghouse helped to standardize railroad components, including the development of a completely new signaling system. He also developed a system of gas mains, and patented a powerful air brake for trains in 1869, which allowed trains to run more safely with greater loads at higher speeds. In the 1880s he turned his attention to the generation of electricity. Unlike Thomas c0016-01.gifEdison, Westinghouse introduced alternating current (AC) into his power stations. In 1895 the Westinghouse Electric Company harnessed Niagara Falls to generate electricity for the lights and streetcars of the nearby town of Buffalo.  
  Whitney, Eli (1765–1825) U.S. inventor who in 1794 patented the cotton gin, a device for separating cotton fiber from its seeds. He also used machine tools to make firearms with fully interchangeable parts creating a standardization system that was the precursor of the assembly line.  
  Whittle, Frank (1907–1996) British engineer. He patented the basic design for the turbojet engine in 1930. In May 1941 the Gloster E 28/39 aircraft first flew with the Whittle jet engine.  
  Wright brothers, Orville (1871–1948) and Wilbur (1867–1912) U.S. inventors, brothers, who pioneered piloted, powered flight. Inspired by Otto c0016-01.gifLilienthal's gliding, they perfected their piloted glider in 1902. In 1903 they built a powered machine, a 12-hp 341-kg/750-lb plane, and became the first to make a successful powered flight, near Kitty Hawk, North Carolina. Orville flew 36.6 m/120 ft in 12 seconds; Wilbur, 260 m/852 ft in 59 seconds.  
  Zworykin, Vladimir Kosma (1889–1982) Russian-born U.S. electronics engineer who invented a television camera tube, the iconoscope, which uses an electron beam to scan the charge pattern on a signal plate, which corresponds to the pattern of light and dark of an image focused on it by a lens. He also developed the electron microscope, an early form of electric eye, an electronic image tube sensitive to infrared light, which was the basis for World War II inventions for seeing in the dark, and in 1929 he demonstrated an improved electronic television system.  




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a storage c0016-01.gifbattery—that is, a group of rechargeable secondary cells. A familiar example is the lead—acid car battery.
metal blended with some other metallic or nonmetallic substance to give it special qualities, such as resistance to corrosion, greater hardness, or tensile strength. Useful alloys include bronze, brass, cupronickel, duralumin, German silver, gunmetal, pewter, solder, steel, and stainless steel.
electricity generator that produces an alternating current.
instrument used in aircraft that measures altitude, or height above sea level. The common type is a form of aneroid barometer, which works by sensing the differences in air pressure at different altitudes. This must continually be recalibrated because of the change in air pressure with changing weather conditions. The c0016-01.gifradar altimeter measures the height of the aircraft above the ground, measuring the time it takes for radio pulses emitted by the aircraft to be reflected.
controlled cooling of a material to increase ductility and strength. The process involves first heating a material (usually glass or metal) for a given time at a given temperature, followed by slow cooling.
process that increases the resistance to corrosion of a metal, such as aluminum, by building up a protective oxide layer on the surface. The natural corrosion resistance of aluminum is provided by a thin film of aluminum oxide; anodizing increases the thickness of this film and thus the corrosion protection.
  antenna or aerial,
in radio and television broadcasting, a conducting device that radiates or receives electromagnetic waves. The design of an antenna depends principally on the wavelength of the signal.
  aqualung, or scuba,
underwater breathing apparatus worn by divers, developed in the early 1940s by the French diver Jacques Cousteau. Compressed-air cylinders strapped to the diver's back are regulated by a valve system and by a mouth tube to provide air to the diver at the same pressure as that of the surrounding water (which increases with the depth).
any artificial channel or conduit for water, originally applied to water supply tunnels, but later used to refer to elevated structures of stone, wood, or iron carrying navigable canals across valleys. One of the first great aqueducts was built in 691
B.C., carrying water for 80 km/50 mi to Ninevah, capital of the ancient Assyrian Empire.
  Archimedes screw
one of the earliest kinds of pump, associated with the Greek mathematician Archimedes. It consists of an enormous spiral screw revolving inside a close-fitting cylinder. It is used, for example, to raise water for irrigation and for land drainage. Of robust and simple construction, it has the advantage of being able to shift water containing mud, sand, gravel, and even larger debris.
  arc lamp, or arc light,
electric light that uses the illumination of an electric arc maintained between two electrodes. The lamp consists of two carbon electrodes, between which a very high voltage is maintained. Electric current arcs (jumps) between the two electrolytes, creating a brilliant light. Its main use in recent years has been in cinema projectors.
in a motor or generator, the wire-wound coil that carries the current and rotates in a magnetic field. (In alternating-current machines, the armature is sometimes stationary.) The pole piece of a permanent magnet or electromagnet and the moving, iron, part of a solenoid, especially if the latter acts as a switch, may also be referred to as armatures.
  atomic clock
timekeeping device regulated by various periodic processes occurring in atoms and molecules, such as atomic vibration or the frequency of absorbed or emitted radiation. The first atomic clock, the ammonia clock, was invented at the U.S. National Bureau of Standards in 1948, and was regulated by measuring the speed at which the nitrogen atom in an ammonia molecule vibrated back and forth. The rate of molecular vibration is not affected by temperature, pressure, or other external influences, and can be used to regulate an electronic clock. Atomic clocks are so accurate that minute adjustments must be made periodically to the length of the year to keep the calendar exactly synchronized with the earth's rotation, which has a tendency to slow down.
  autogiro, or autogyro,
heavier-than-air craft that supports itself in the air with a rotary wing, or rotor. The autogiro's rotor provides only lift and not propulsion; it has been superseded by the helicopter, in which the rotor provides both. The autogiro is propelled by an orthodox propeller.
the first synthetic plastic, created by the Belgian-born U.S. chemist Leo Baekeland in 1909. Bakelite is hard, tough, and heatproof, and is used as an electrical insulator. It is made by the reaction of phenol with formaldehyde, producing a powdery resin that sets solid when heated. Objects are made by subjecting the resin to compression molding (simultaneous heat and pressure in a mold).
  ball valve
valve that works by the action of external pressure raising a ball and thereby opening a hole. An example is the valve used in lavatory cisterns to cut off the water supply when it reaches the correct level.
  basic-oxygen process
the most widely used method of steel-making, involving the blasting of oxygen at supersonic speed into molten pig iron.
any energy-storage device allowing release of electricity on demand. It is made up of one or more electrical cells. Primary-cell batteries are disposable; secondary-cell batteries, or c0016-01.gifaccumulators, are rechargeable. Primary-cell batteries are an extremely uneconomical form of energy, since they produce only 2% of the power used in their manufacture.
  Bessemer process
the first cheap method of making c0016-01.gifsteel, invented by the engineer and inventor Henry Bessemer in England in 1856. In the Bessemer process compressed air is blown into the bottom of a converter, a furnace shaped like a cement mixer, containing molten pig iron. The excess carbon in the iron burns off, other impurities form a slag, and the furnace is emptied by tilting. The process has since been superseded by the c0016-01.gifbasic–oxygen process.




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optical instrument for viewing an object in magnification with both eyes; for example, field glasses and opera glasses. Binoculars consist of two telescopes containing lenses and prisms, which produce a stereoscopic effect as well as magnifying the image.
  blast furnace
smelting furnace used to extract metals from their ores, chiefly pig iron from iron ore. The temperature is raised by the injection of an air blast.
  Bourdon gauge
instrument for measuring pressure, patented by the French watchmaker Eugène Bourdon in 1849. The gauge contains a C-shaped tube, closed at one end. When the pressure inside the tube increases, the tube uncurls slightly causing a small movement at its closed end. A system of levers and gears magnifies this movement and turns a pointer, which indicates the pressure on a circular scale. Bourdon gauges are often fitted to cylinders of compressed gas used in industry and hospitals.
  cable television
distribution of broadcast signals through cable relay systems. Systems using coaxial and fiber-optic cable, are increasingly used for distribution and development of home-based interactive services, typically telephones.
  cesium clock
extremely accurate type of c0016-01.gifatomic clock. Because of its internal structure, a cesium atom produces or absorbs radiation of a very precise frequency (9,192,631,770 Hz) that varies by less than one part in 10 billion. This frequency has been used to define the second, and is the basis of atomic clocks used in international timekeeping.
beam or structure that is fixed at one end only, though it may be supported at some point along its length; for example, a diving board. The cantilever principle, widely used in construction engineering, eliminates the need for a second main support at the free end of the beam, allowing for more elegant structures and reducing the amount of materials required. Many large-span bridges have been built on the cantilever principle.
  carbon fiber
fine, black, silky filament of pure carbon produced by heat treatment from a special grade of Courtelle acrylic fiber and used for reinforcing plastics. The resulting composite is very stiff and, weight for weight, has four times the strength of high-tensile steel. It is used in the aerospace industry, cars, and electrical and sports equipment.
mixing of a gas, such as air, with a volatile hydrocarbon fuel, such as gasoline, kerosene, or fuel oil, in order to form an explosive mixture. The process, which ensures that the maximum amount of heat energy is released during combustion, is used in internal-combustion engines. In most gasoline engines the liquid fuel is atomized and mixed with air by means of a device called a carburetor.
  cast iron
cheap but invaluable constructional material, most commonly used for car engine blocks. Cast iron is partly refined pig (crude) iron, which is very fluid when molten and highly suitable for shaping by casting; it contains too many impurities (for example, carbon) to be readily shaped in any other way. Solid cast iron is heavy and can absorb great shock but is very brittle.
  catalytic converter
device fitted to the exhaust system of a motor vehicle in order to reduce toxic emissions from the engine. It converts harmful exhaust products to relatively harmless ones by passing the exhaust gases over a mixture of catalysts coated on a metal or ceramic honeycomb (a structure that increases the surface area and therefore the amount of active catalyst with which the exhaust gases will come into contact).
  cellular phone, or cellphone,
mobile radio telephone, one of a network connected to the telephone system by a computercontrolled communication system. Service areas are divided into small "cells," about 5 km/3 mi across, each with a separate low-power transmitter.
any bonding agent used to unite particles in a single mass or to cause one surface to adhere to another. Portland cement is a powder which when mixed with water and sand or gravel turns into mortar or concrete. Cement sets by losing water. The term "cement" covers a variety of materials, such as fluxes and pastes, and also bituminous products obtained from tar.
  charge-coupled device
(CCD) device for forming images electronically, using a layer of silicon that releases electrons when struck by incoming light. The electrons are stored in pixels and read off into a computer at the end of the exposure. CCDs have now almost entirely replaced photographic film for applications such as astrophotography where extreme sensitivity to light is paramount.
  coaxial cable
electric cable that consists of a solid or stranded central conductor insulated from and surrounded by a solid or braided conducting tube or sheath. It can transmit the high-frequency signals used in television, telephones, and other telecommunications transmissions.
  compact disk (CD)
disk for storing digital information, about 12 cm/4.5 in across, mainly used for music, when it can have over an hour's playing time. A laser beam etches the compact disc with microscopic pits that carry a digital code representing the sounds; the pitted surface is then coated with aluminum. During playback, a laser beam reads the code and produces signals that are changed into near-exact replicas of the original sounds.
building material composed of cement, stone, sand, and water. It has been used since Egyptian and Roman times. Since the late 19th century it has been combined with steel to increase its tension capacity. Reinforced concrete and prestressed concrete are strengthened by combining concrete with another material, such as steel rods or glass fibers. The addition of carbon fibers to concrete increases its conductivity. The electrical resistance of the concrete changes with increased stress or fracture, so this "smart concrete" can be used as an early indicator of structural damage.
  delta wing
aircraft wing shaped like the Greek letter delta. Its design enables an aircraft to pass through the sound barrier with little effect. The supersonic airliner Concorde and the U.S. space shuttle have delta wings.
  diesel engine
an internal-combustion engine that burns a lightweight fuel oil and operates by compressing air until it becomes sufficiently hot to ignite the fuel. It is a piston-incylinder engine, like the c0016-01.gifgasoline engine, but only air (rather than an air-and-fuel mixture) is taken into the cylinder on




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  the first piston stroke (down). The piston moves up and compresses the air until it is at a very high temperature. The fuel oil is then injected into the hot air, where it burns, driving the piston down on its power stroke. For this reason the engine is called a compression-ignition engine.  
  digital audio tape (DAT)
digitally recorded audio tape produced in cassettes that can carry up to two hours of sound on each side and are about half the size of standard cassettes. DAT players/recorders were developed in 1987. The first DAT for computer data was introduced in 1988.
  digital camera
camera that uses a c0016-01.gif charge-coupled device to take pictures which are stored as digital data rather than on film. The output from digital cameras can be downloaded onto a computer for retouching or storage, and can be readily distributed as computer files.
  digital compact cassette (DCC)
digitally recorded audio cassette that is roughly the same size as a standard cassette. It cannot be played on a normal tape recorder.
  electron microscope
instrument that produces a magnified image by using a beam of electrons instead of light rays, as in an optical c0016-01.gifmicroscope. An electron lens—an arrangement of electromagnetic coils—control and focus the beam. Electrons are not visible to the eye, so instead of an eyepiece there is a fluorescent screen or a photographic plate on which the electrons form an image. The wavelength of the electron beam is much shorter than that of light, so much greater magnification and resolution (ability to distinguish detail) can be achieved. A transmission electron microscope passes the electron beam through a very thin slice of a specimen. A scanned-probe microscope, which has a probe with a tip so fine that it may consist only of a single atom, runs across the surface of the specimen. A scanning electron microscope looks at the exterior of a specimen. In the scanning tunneling microscope, an electric current flows through the probe to construct an image of the specimen. In the atomic force microscope, the force felt by the probe is measured and used to form the image. A scanning transmission electron microscope (STEM) can produce a magnification of 90 million times.
glass that has been formed into fine fibers, either as long continuous filaments or as a fluffy, short-fibered glass wool. Fiberglass is heat- and fire-resistant and a good electrical insulator. It has applications in the field of fiber optics and as a strengthener for plastics in GRP (glass-reinforced plastics).
  four-stroke cycle
the engine-operating cycle of most gasoline and c0016-01.gifdiesel engines. The "stroke" is an upward or downward movement of a piston in a cylinder. In a gasoline engine the cycle begins with the induction of a fuel mixture as the piston goes down on its first stroke. On the second stroke (up) the piston compresses the mixture in the top of the cylinder. An electric spark then ignites the mixture, and the gases produced force the piston down on its third, power, stroke. On the fourth stroke (up) the piston expels the burned gases from the cylinder into the exhaust. The four-stroke cycle is also called the Otto cycle. The diesel engine cycle works in a slightly different way to that of the gasoline engine on the first two strokes.
  gasoline engine
a reciprocating piston engine in which a number of pistons move up and down in cylinders. A mixture of gasoline and air is introduced to the space above the pistons and ignited. The gases produced force the pistons down, generating power. The engine-operating cycle is repeated every four strokes (upward or downward movement) of the piston, this being known as the c0016-01.giffour-stroke cycle. The motion of the pistons rotate a crankshaft, at the end of which is a heavy flywheel. From the flywheel the power is transferred to the car's driving wheels via the transmission system of clutch, gearbox, and final drive.
one of the three main printing methods, in which printing is done from a plate etched with a pattern of recessed cells in which the ink is held. The greater the depth of a cell, the greater the strength of the printed ink.
  heat treatment
in industry, the subjection of metals and alloys to controlled heating and cooling after fabrication to relieve internal stresses and improve their physical properties. Methods include c0016-01.gifannealing, quenching, and tempering.
  hydraulic press
two liquid-connected pistons in cylinders, one of narrow bore, one of large bore. A force applied to the narrow piston applies a certain pressure (force per unit area) to the liquid, which is transmitted to the larger piston. Because the area of this piston is larger, the force exerted on it is larger. Thus the original force has been magnified, although the smaller piston must move a great distance to move the larger piston only a little.
  hydrogen maser clock
the most accurate type of c0016-01.gifatomic clock based on the radiation from hydrogen atoms. The hydrogen maser clock at the U.S. Naval Research Laboratory, Washington, D.C., is estimated to lose one second in 1,700,000 years. Cooled hydrogen maser clocks could theoretically be accurate to within one second in 300 million years.
on a submarine, a movable horizontal fin angled downward or upward when the vessel is descending or ascending. It is also a highly maneuvrable motorboat with its bottom rising in steps to the stern, or a hydrofoil boat that skims over the surface of the water when driven at high speed.
device included in an electrical circuit because of its inductance.
  interactive video (IV)
computer-mediated system that enables the user to interact with and control information (including text, recorded speech, or moving images) stored on video disk. IV is most commonly used for training purposes, using analog video disk, but has wider applications with digital video systems such as CD-I (Compact Disk Interactive, from Philips and Sony) which are based on the CD-ROM format derived from audio compact disks.
  jet engine
a kind of gas c0016-01.gifturbine. Air, after passing through a forward-facing intake, is compressed by a compressor, or fan, and fed into a combustion chamber. Fuel (usually kerosene) is sprayed in and ignited. The hot gas produced expands rapidly rearward, spinning a turbine that drives the compressor before being finally ejected from a rearward-facing tail pipe, or nozzle, at very high speed. Reaction to the jet of gases streaming backward produces a propulsive thrust forward, which acts on the aircraft through its engine-




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  mountings, not from any pushing of the hot gas stream against the static air.  
advanced type of hydrofoil boat built by Boeing, propelled by water jets. It features horizontal, fully submerged hydrofoils fore and aft and has a sophisticated computerized control system to maintain its stability in all waters.
(acronym for light amplification by stimulated emission of radiation) device for producing a narrow beam of light, capable of traveling over vast distances without dispersion, and of being focused to give enormous power densities. The uses of lasers include communications (a laser beam can carry much more information than can radio waves), cutting, drilling, welding, satellite tracking, medical and biological research, and surgery. Any substance in which the majority of atoms or molecules can be put into an excited energy state can be used as laser material. Many solid, liquid, and gaseous substances have been used, including synthetic ruby crystal, carbon dioxide gas, a helium–neon gas mixture, and complex organic dyes.
  lie detector
instrument that records graphically certain body activities, such as thoracic and abdominal respiration, blood pressure, pulse rate, and galvanic skin response (changes in electrical resistance of the skin). Marked changes in these activities when a person answers a question may indicate that the person is lying.
  light-emitting diode (LED)
electronic component that converts electrical energy into light or infrared radiation in the range of 550 nm (green light) to 1300 nm (infrared). It is used for displaying symbols in electronic instruments and devices. An LED is a diode made of semiconductor material, such as gallium arsenide phosphide, that glows when electricity is passed through it. The first digital watches and calculators had LED displays, but many later models use c0016-01.gifliquid-crystal displays.
  linear motor
type of electric motor, an induction motor in which the fixed stator and moving armature are straight and parallel to each other (rather than being circular and one inside the other as in an ordinary induction motor). Linear motors are used, for example, to power sliding doors. There is a magnetic force between the stator and armature; this force has been used to support a vehicle, as in the experimental maglev linear motor train.
  liquid-crystal display (LCD)
display of numbers (for example, in a calculator) or pictures (such as on a pocket television screen) produced by molecules of a substance in a semiliquid state with some crystalline properties, so that clusters of molecules align in parallel formations. The display is a blank until the application of an electric field, which "twists" the molecules so that they reflect or transmit light falling on them.
any machine for weaving yarn or thread into cloth. A loom is a frame on which a set of lengthwise threads (warp) is strung. A second set of threads (weft), carried in a shuttle, is inserted at right angles over and under the warp. In most looms the warp threads are separated by a device called a treddle to create a gap, or shed, through which the shuttle can be passed in a straight line. A kind of comb called a reed presses each new line of weave tight against the previous ones.
electromechanical device that converts electrical signals into sound waves, which are radiated into the air. The most common type of loudspeaker is the moving-coil speaker. Electrical signals from a radio, for example, are fed to a coil of fine wire wound around the top of a cone. A magnet surrounds the coil. When signals pass through it, the coil becomes an electromagnet, which by moving causes the cone to vibrate, setting up sound waves.
  magnetic tape
narrow plastic ribbon coated with an easily magnetizable material on which data can be recorded. It is used in sound recording, audiovisual systems (videotape), and computing.
  metal detector
electronic device for detecting metal, usually below ground, developed from the wartime mine detector. In the head of the metal detector is a coil, which is part of an electronic circuit. The presence of metal causes the frequency of the signal in the circuit to change, setting up an audible note in the headphones worn by the user.
any instrument used for measurement. The term is often compounded with a prefix to denote a specific type of meter: for example, ammeter, voltmeter, flowmeter, or pedometer.
primary component in a sound-reproducing system, whereby the mechanical energy of sound waves is converted into electrical signals by means of a transducer. One of the simplest is the telephone receiver mouthpiece, invented by Alexander Graham Bell in 1876; other types of microphone are used with broadcasting and sound-film apparatus. Telephones have a carbon microphone, which reproduces only a narrow range of frequencies. For live music a moving-coil microphone is often used. In it, a diaphragm that vibrates with sound waves moves a coil through a magnetic field, thus generating an electric current. The ribbon microphone combines the diaphragm and coil. The condenser microphone is most commonly used in recording and works by a capacitor.
instrument for forming magnified images with high resolution for detail. Optical and electron microscopes are the ones chiefly in use; other types include acoustic, scanning tunneling, and atomic force microscopes.
rocket-propelled weapon, which may be nuclear-armed. Modern missiles are often classified as surface-to-surface missiles (SSM), air-to-air missiles (AAM), surface-to-air missiles (SAM), or air-to-surface missiles (ASM). A cruise missile is in effect a pilotless, computer-guided aircraft; it can be sea-launched from submarines or surface ships, or launched from the air or the ground.
railroad that runs on a single rail; the cars can be balanced on it or suspended from it. It was invented in 1882 to carry light loads, and when run by electricity was called a telpher.
anything that produces or imparts motion; a machine that provides mechanical power—for example, an electric motor.
  motorcycle, or motorbike,
two-wheeled vehicle propelled by a c0016-01.gifgasoline engine.
  movie camera
camera that takes a rapid sequence of still photographs called frames. When the frames are projected one after the other onto a screen, they appear to show movement,




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  because our eyes hold onto the image of one picture until the next one appears.  
synthetic long-chain polymer similar in chemical structure to protein. Nylon was the first all-synthesized fiber, made from petroleum, natural gas, air, and water by the Du Pont firm in 1938. It is used in the manufacture of molded articles, textiles, and medical sutures. Nylon fibers are stronger and more elastic than silk and are relatively insensitive to moisture and mildew.
  offset printing
the most common method of printing, which uses smooth (often rubber) printing plates. It works on the principle of lithography: that grease and water repel one another.
  optical fiber
very fine, optically pure glass fiber through which light can be reflected to transmit images or data from one end to the other. Although expensive to produce and install, optical fibers can carry more data than traditional cables, and are less susceptible to interference. Standard optical fiber transmitters can send up to 10 billion bits of information per second by switching a laser beam on and off. Optical fibers are increasingly being used to replace metal communications cables, the messages being encoded as digital pulses of light rather than as fluctuating electric current. Current research is investigating how optical fibers could replace wiring inside computers. Bundles of optical fibers are also used in endoscopes to inspect otherwise inaccessible parts of machines or of the living body.
cycle alternative name for the c0016-01.giffour-stroke cycle, introduced by the German engineer Nikolaus Otto (1832–1891) in 1876. It improved on existing piston engines by compressing the fuel mixture in the cylinder before it was ignited.
  oxyacetylene torch
gas torch that burns ethyne (acetylene) in pure oxygen, producing a high-temperature flame (3,000°C/5,400°F). It is widely used in welding to fuse metals. In the cutting torch, a jet of oxygen burns through metal already melted by the flame.
a medical device implanted under the skin of a patient whose heart beats inefficiently. It delivers minute electric shocks to stimulate the heart muscles at regular intervals and restores normal heartbeat.
barrel-shaped device used in reciprocating engines (steam, gasoline, diesel oil) to harness power. Pistons are driven up and down in cylinders by expanding steam or hot gases. They pass on their motion via a connecting rod and crank to a crankshaft, which turns the driving wheels. In a pump or compressor, the role of the piston is reversed, being used to move gases and liquids.
in mechanics, the distance between the adjacent threads of a screw or bolt. When a screw is turned through one full turn it moves a distance equal to the pitch of its thread.
  Pitot tube
instrument that measures fluid (gas and liquid) flow. It is used to measure the speed of aircraft, and works by sensing pressure differences in different directions in the airstream.
  pneumatic drill
drill operated by compressed air, used in mining and tunneling, for drilling shot holes (for explosives), and in road repairs for breaking up pavements. It contains an airoperated piston that delivers hammer blows to the drill bit many times a second.
  Polaroid camera
instant-picture camera, invented by Edwin Land in the United States in 1947. The original camera produced black-and-white prints in about one minute. Modern cameras can produce black-and-white prints in a few seconds, and color prints in less than a minute. A Polaroid camera ejects a piece of film on paper immediately after the picture has been taken. The film consists of layers of emulsion and color dyes together with a pod of chemical developer. When the film is ejected the pod bursts and processing occurs in the light, producing a paper-backed print.
an electrical resistor that can be divided so as to compare, measure, or control voltages. In radio circuits, any rotary variable resistance (such as volume control) is referred to as a potentiometer.
screwlike device used to propel some ships and airplanes. A propeller has a number of curved blades that describe a helical path as they rotate with the hub, and accelerate fluid (liquid or gas) backward during rotation. Reaction to this backward movement of fluid sets up a propulsive thrust forward.
artificial device used to substitute for a body part which is defective or missing. Prostheses include artificial limbs, hearing aids, false teeth and eyes, heart c0016-01.gifpacemakers and plastic heart valves and blood vessels.
any device for moving liquids and gases, or compressing gases. Some pumps, such as the traditional lift pump used to raise water from wells, work by a reciprocating (up-and-down) action. Movement of a piston in a cylinder with a one-way valve creates a partial vacuum in the cylinder, thereby sucking water into it. Gear pumps, used to pump oil in a car's lubrication system, have two meshing gears that rotate inside a housing, and the teeth move the oil. Rotary pumps contain a rotor with vanes projecting from it inside a casing, sweeping the liquid round as they move.
(acronym for radio direction and ranging) device for locating objects in space, direction finding, and navigation by means of transmitted and reflected high-frequency radio waves. The direction of an object is ascertained by transmitting a beam of short-wavelength (1–100 cm/0.5–40 in), short-pulse radio waves, and picking up the reflected beam. Distance is determined by timing the journey of the radio waves (traveling at the speed of light) to the object and back again. Radar is essential to navigation in darkness, cloud, and fog, and is widely used in warfare to detect enemy aircraft and missiles. Radar is also used to detect objects underground, for example service pipes, and in archeology.
any of various shiny textile fibers and fabrics made from cellulose. It is produced by pressing whatever cellulose solution is used through very small holes and solidifying the resulting filaments. A common type is c0016-01.gifviscose, which consists of regenerated filaments of pure cellulose.
  reinforced concrete
material formed by casting concrete in timber or metal formwork around a cage of steel reinforcement. The steel gives added strength by taking up the tension stresses, while the concrete takes up the compression stresses.




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  reflex camera
camera that uses a mirror and prisms to reflect light passing through the lens into the viewfinder, showing the photographer the exact scene that is being shot. When the shutter button is released the mirror springs out of the way, allowing light to reach the film. The most common type is the single-lens reflex (SLR) camera. The twin-lens reflex (TLR) camera has two lenses: one has a mirror for viewing, the other is used for exposing the film.
in electrical engineering, an electromagnetic switch. A small current passing through a coil of wire wound around an iron core attracts an c0016-01.gifarmature whose movement closes a pair of sprung contacts to complete a secondary circuit, which may carry a large current or activate other devices. The solidstate equivalent is a thyristor switching device.
projectile driven by the reaction of gases produced by a fast-burning fuel. Unlike jet engines, which are also reaction engines, modern rockets carry their own oxygen supply to burn their fuel and do not require any surrounding atmosphere.
common method of shaping metal. Rolling is carried out by giant mangles, consisting of several sets, or stands, of heavy rollers positioned one above the other. Red-hot metal slabs are rolled into sheet and also (using shaped rollers) girders and rails. Metal sheets are often cold-rolled finally to impart a harder surface.
(acronym for self-contained underwater breathing apparatus) another name for c0016-01.gifaqualung.
automatic control system used in aircraft, automobiles, and other complex machines. A specific input, such as moving a lever or joystick, causes a specific output, such as feeding current to an electric motor that moves, for example, the rudder of the aircraft. At the same time, the position of the rudder is detected and fed back to the central control, so that small adjustments can continually be made to maintain the desired course.
navigational instrument for determining latitude by measuring the angle between some heavenly body and the horizon. It can be used only in clear weather.
any of various alloys used when melted for joining metals such as copper, its common alloys (brass and bronze), and tin-plated steel, as used for making food cans. Soft solders (usually alloys of tin and lead, sometimes with added antimony) melt at low temperatures (about 200°C/392°F), and are widely used in the electrical industry for joining copper wires. Hard (or brazing) solders, such as silver solder (an alloy of copper, silver, and zinc), melt at much higher temperatures and form a much stronger joint. Printed circuit boards for computers are assembled by soldering.
  solid-state circuit
electronic circuit where all the components (resistors, capacitors, transistors, and diodes) and interconnections are made at the same time, and by the same processes, in or on one piece of single-crystal silicon. The small size of this construction accounts for its use in electronics for space vehicles and aircraft.
(acronym for sound navigation and ranging) method of locating underwater objects by the reflection of ultrasonic waves. The time taken for an acoustic beam to travel to the object and back to the source enables the distance to be found since the velocity of sound in water is known. Sonar devices, or echo sounders, were developed in 1920, and are the commonest means of underwater navigation.
band at one side of a cine film on which the accompanying sound is recorded. Usually it takes the form of an optical track (a pattern of light and shade). The pattern is produced on the film when signals from the recording microphone are made to vary the intensity of a light beam. During playback, a light is shone through the track on to a photocell, which converts the pattern of light falling on it into appropriate electrical signals. These signals are then fed to loudspeakers to recreate the original sounds.
  spark plug
plug that produces an electric spark in the cylinder of a gasoline engine to ignite the fuel mixture. It consists essentially of two electrodes insulated from one another. High-voltage (18,000 V) electricity is fed to a central electrode via the distributor. At the base of the electrode, inside the cylinder, the electricity jumps to another electrode earthed to the engine body, creating a spark.
  stainless steel
widely used c0016-01.gifalloy of iron, chromium, and nickel that resists rusting. Its chromium content also gives it a high tensile strength. It is used for cutlery and kitchen fittings, and in surgical instruments.
alloy or mixture of iron and up to 1.7% carbon, sometimes with other elements, such as manganese, phosphorus, sulfur, and silicon. Steel has innumerable uses, including ship and car manufacture, skyscraper frames, and machinery of all kinds.
vessel designed to operate under water, especially a small submarine used by engineers and research scientists as a ferry craft to support diving operations. The most advanced submersibles are the so-called lock-out type, which have two compartments: one for the pilot, the other to carry divers. The diving compartment is pressurized and provides access to the sea.
any material made from chemicals. Since the 1900s, more and more of the materials used in everyday life are synthetics, including plastics (polythene, polystyrene), synthetic fibers (nylon, acrylics, polyesters), synthetic resins, and synthetic rubber. Most naturally occurring organic substances are now made synthetically, especially pharmaceuticals.
combined speedometer and clock that records a vehicle's speed (on a small card disk, magnetic disk, or tape) and the length of time the vehicle is moving or stationary. It is used to monitor a truckdriver's working hours.
  tape recording, magnetic
method of recording electric signals on a layer of iron oxide, or other magnetic material, coating a thin plastic tape. The electrical signals from the microphone are fed to the electromagnetic recording head, which magnetizes the tape in accordance with the frequency and amplitude of the original signal. The impulses may be audio (for sound recording), video (for television), or data (for computer). For playback, the tape is passed over the same, or another, head to convert magnetic into electrical signals, which are then amplified for reproduction. Tapes are easily demagnetized (erased) for reuse, and come in cassette, cartridge, or reel form.




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  teleprinter, or teletypewriter,
transmitting and receiving device used in telecommunications to handle coded messages. Teleprinters are automatic typewriters keyed telegraphically to convert typed words into electrical signals (using a five-unit Baudot code) at the transmitting end, and signals into typed words at the receiving end.
(acronym for teleprinter exchange) international telecommunications network that handles telegraph messages in the form of coded signals. It uses c0016-01.gifteleprinters for transmitting and receiving, and makes use of land lines (cables) and radio and satellite links to make connections between subscribers.
  Tesla coil
air core transformer with the primary and secondary windings tuned in resonance to produce high-frequency, high-voltage electricity.
instrument for the measurement of horizontal and vertical angles, used in surveying. It consists of a small telescope mounted so as to move on two graduated circles, one horizontal and the other vertical, while its axes pass through the center of the circles.
electric temperature measuring device consisting of a circuit having two wires made of different metals welded together at their ends. A current flows in the circuit when the two junctions are maintained at different temperatures (Seebeck effect). The electromotive force generated—measured by a millivoltmeter—is proportional to the temperature difference.
instrument for measuring temperature. There are many types, designed to measure different temperature ranges to varying degrees of accuracy. Each makes use of a different physical effect of temperature. Expansion of a liquid is employed in common liquid-in-glass thermometers, such as those containing mercury or alcohol. The more accurate gas thermometer uses the effect of temperature on the pressure of a gas held at constant volume. A resistance thermometer takes advantage of the change in resistance of a conductor (such as a platinum wire) with variation in temperature.
temperature-controlling device that makes use of feedback. It employs a temperature sensor (often a bimetallic strip) to operate a switch or valve to control electricity or fuel supply. Thermostats are used in central heating, ovens, and car engines.
device in which, by electromagnetic induction, an alternating current (AC) of one voltage is transformed to another voltage, without change of frequency. Transformers are widely used in electrical apparatus of all kinds, and in particular in power transmission where high voltages and low currents are utilized.
solid-state electronic component, made of semiconductor material, with three or more electrodes, that can regulate a current passing through it. A transistor can act as an amplifier, oscillator, photocell, or switch, and (unlike earlier thermionic valves) usually operates on a very small amount of power. Transistors commonly consist of a tiny sandwich of germanium or silicon, alternate layers having different electrical properties because they are impregnated with minute amounts of different impurities.
an engine in which steam, water, gas, or air is made to spin a rotating shaft by pushing on angled blades, like a fan. Turbines are among the most powerful machines. Steam turbines are used to drive generators in power stations and ships' propellers; water turbines spin the generators in hydroelectric power plants; and gas turbines power most aircraft and drive machines in industry. A steam turbine consists of a shaft, or rotor, which rotates inside a fixed casing (stator). The rotor carries "wheels" consisting of blades, or vanes. The stator has vanes set between the vanes of the rotor, which direct the steam through the rotor vanes at the optimum angle. When steam expands through the turbine, it spins the rotor by reaction and is called a reaction turbine. The impulse turbine works by directing a jet of steam at blades on a rotor. Impulse water turbines work on the same principle as the water wheel and consist of sets of buckets arranged around the edge of a wheel; reaction turbines look much like propellers and are fully immersed in the water. In a gas turbine a compressed mixture of air and gas, or vaporized fuel, is ignited, and the hot gases produced expand through the turbine blades, spinning the rotor. In the industrial gas turbine, the rotor shaft drives machines. In the jet engine, the turbine drives the compressor, which supplies the compressed air to the engine, but most of the power developed comes from the jet exhaust in the form of propulsive thrust.
turbine-driven device fitted to engines to force more air into the cylinders, producing extra power. The turbocharger consists of a "blower," or compressor, driven by a turbine, which in most units is driven by the exhaust gases leaving the engine.
jet engine of the type used by most airliners, so called because of its huge front fan. The fan sends air not only into the engine for combustion but also around the engine for additional thrust. This results in a faster and more fuel-efficient propulsive jet.
jet engine that derives its thrust partly from a jet of exhaust gases, but mainly from a propeller powered by a turbine in the jet exhaust. Turboprops are more economical than turbojets but can be used only at relatively low speeds.
  two-stroke cycle
operating cycle for internal combustion piston engines. The engine cycle is completed after just two strokes (up or down) of the piston, which distinguishes it from the more common c0016-01.giffour-stroke cycle. In a typical two-stroke engine, fuel mixture is drawn into the crankcase as the piston moves up on its first stroke to compress the mixture above it. Then the compressed mixture is ignited, and hot gases are produced, which drive the piston down on its second stroke. As it moves down, it uncovers an opening (port) that allows the fresh fuel mixture in the crankcase to flow into the combustion space above the piston. At the same time, the exhaust gases leave through another port. Power mowers, most marine diesel engines, and lightweight motorcycles use two-stroke gasoline engines, which are cheaper and simpler than four-strokes.
means by which text, or copy, is prepared for printing, now usually carried out by computer. Text is keyed on a typesetting machine in a similar way to typing. Laser or light impulses are projected on to light-sensitive film that, when developed, can be used to make plates for printing.




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keyboard machine that produces characters on paper. Recent typewriters work electronically, are equipped with a memory, and can be given an interface that enables them to be connected to a computer. The word processor has largely replaced the typewriter for typing letters and text.
  vacuum flask, or Dewar flask or Thermos flask,
container for keeping things either hot or cold. It has two silvered glass walls with a vacuum between them, in a metal or plastic outer case. This design reduces the three forms of heat transfer: radiation (prevented by the silvering), conduction, and convection (both prevented by the vacuum). A vacuum flask is therefore equally efficient at keeping cold liquids cold or hot liquids hot.
  video camera, or camcorder,
portable television camera that records moving pictures electronically on magnetic tape. It produces an electrical output signal corresponding to rapid line-by-line scanning of the field of view. The output is recorded on videocassette and is played back on a television screen via a videocassette recorder.
  videocassette recorder (VCR)
device for recording on and playing back video cassettes; see c0016-01.gifvideotape recorder.
  video disk
disk with pictures and sounds recorded on it, played back by laser. The video disk is a type of c0016-01.gifcompact disk. The video disk is chiefly used to provide commercial films for private viewing. Most systems use a 30 cm/12 in rotating vinyl disk coated with a reflective material. Laser scanning recovers picture and sound signals from the surface where they are recorded as a spiral of microscopic pits.
  videotape recorder (VTR)
device for recording pictures and sound on cassettes or spools of magnetic tape. Video recording works in the same way as audio c0016-01.giftape recording: the picture information is stored as a line of varying magnetism, or track, on a plastic tape covered with magnetic material. The main difficulty—the huge amount of information needed to reproduce a picture—is overcome by arranging the video track diagonally across the tape. During recording, the tape is wrapped around a drum in a spiral fashion. The recording head rotates inside the drum. The combination of the forward motion of the tape and the rotation of the head produces a diagonal track. The audio signal accompanying the video signal is recorded as a separate track along the edge of the tape.
system in which information (text and simple pictures) is displayed on a television (video) screen. There are two basic systems, known as teletext and viewdata. In the teletext system information is broadcast with the ordinary television signals, whereas in the viewdata system information is relayed to the screen from a central data bank via the telephone network. Both systems require the use of a television receiver (or a connected videotape recorder) with special decoder.
yellowish, syrupy solution made by treating cellulose with sodium hydroxide and carbon disulfide. The solution is then regenerated as continuous filament for the making of c0016-01.gifrayon and as cellophane.
  Wankel engine
rotary gasoline engine developed by the German engineer Felix Wankel (1902–1988) in the 1950s. It operates according to the same stages as the c0016-01.giffour-stroke gasoline engine cycle, but these stages take place in different sectors of a figure-eight chamber in the space between the chamber walls and a triangular rotor. Power is produced once on every turn of the rotor. The Wankel engine is simpler in construction than the four-stroke piston gasoline engine, and produces rotary power directly (instead of via a crankshaft). Problems with rotor seals have prevented its widespread use.
joining pieces of metal (or nonmetal) at faces rendered plastic or liquid by heat or pressure (or both). The principal processes today are gas and arc welding, in which the heat from a gas flame or an electric arc melts the faces to be joined. Additional "filler metal" is usually added to the joint. Forge (or hammer) welding, employed by blacksmiths since early times, was the only method available until the late 19th century. Resistance welding is another electric method in which the weld is formed by a combination of pressure and resistance heating from an electric current. Recent developments include electric-slag, electron-beam, high-energy laser, and the still experimental radio-wave energy-beam welding processes.
  wind tunnel
test tunnel in which air is blown over, for example, a stationary model aircraft, motor vehicle, or locomotive to simulate the effects of movement. Lift, drag, and airflow patterns are observed by the use of special cameras and sensitive instruments. Wind-tunnel testing assesses aerodynamic design, prior to full-scale construction.
  Further Reading  
  Adler, Michael H. The Writing Machine (1973)  
  Alexander, William, and Street, Arthur Metals in the Service of Man (1972)  
  American Society for Testing and Materials Chemical and Spectrometric Test Methods for Steel (1992)  
  Ashby, M. F., and Jones, D. R. H. Engineering Materials: An Introduction to their Properties and Application (1980)  
  Ball, P. Designing the Molecular World: Chemistry at the Frontier (1994)  
  Batty, Peter The House of Krupp (1966)  
  Beeching, Wilfred A. Century of the Typewriter (1990)  
  Bruce, R. V. Alexander Graham Bell and the Conquest of Solitude (1973)  
  Bud, R. The Uses of Life: A History of Biotechnology (1993)  
  Buchanan, R. A. The Power of the Machine (1992)  
  Burton, Anthony The Canal Builders (1981)  
  Cahn, Robert W. Artifice and Artifacts: 100 Essays in Materials Science (1992)  
  Cahn, Robert W., and Haasen, Peter (eds.) Physical Metallurgy (1974; 3rd revised edition 1993)  
  Carr, Marilyn The AT Reader: Theory and Practice in Appropriate Technology (1985)  




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  Connot, R. Thomas A Edison (1987)  
  Crouch, T. D. The Bishop's Boys: A Life of Wilbur and Orville Wright (1989)  
  Davies, Hunter A Biographical Study of the Father of the Railways: George Stephenson (1977)  
  Dennis, W. H. A Hundred Years of Metallurgy (1963)  
  Dickinson, H. W. and Vowles, H. P. James Watt and the Industrial Revolution (1943)  
  Dudley, Eric The Critical Villager (1993)  
  Dunn, P. Appropriate Technology: Technology with a Human Face (1978)  
  Eber, Dorothy Genius at Work: Images of Alexander Graham Bell (1982)  
  Edison, Thomas (ed. D. Runes) Diary and Sundry Observations (1949)  
  Faraday, Michael Experimental Researches in Electricity (1839–55)  
  Forester, T. (ed.) The Materials Revolution (1988)  
  Fussell, G. E. Jethro Tull (1973)  
  Gamser, Matthew; Appleton, Helen; and Carter, Nicola (eds.) Tinker, Tiller, Technical Change: Technologies from the People (1990)  
  Hadfield, Charles The Canal Age (1968)  
  Harrison, Paul The Third World Tomorrow (1980)  
  Herndon, B. Ford (1969)  
  Ing, Janet Johann Gutenberg and His Bible (1988)  
  Josephson, M. Edison: A Biography (1959 )  
  Kaplinsky, Raphael The Economies of Small: Appropriate Technology in a Changing World (1990)  
  Kaufman, M. The First Century of Plastics (1963)  
  Klass, Gert von Krupps: The Story of an Industrial Empire (trs 1954)  
  Lacey, R. Ford: The Man and the Machine (1986)  
  Lindbergh, Charles The Spirit of St Louis (1953–75)  
  McNeil, Ian (ed.) An Encyclopaedia of the History of Technology (1990)  
  Manchester, William The Arms of Krupp (1959)  
  Millard, A. Edison and the Business of Invention (1990)  
  Newcomb, Horace (ed.) Encyclopedia of Television (1997)  
  Nye, D. Henry Ford: Ignorant Idealist (1979)  
  Pearce, R. M. Thomas Telford (1973)  
  Penfold, A. (ed.) Thomas Telford: Engineer (1980)  
  Psaras, Peter A., and Langford, A. Dale Advancing Materials Research (1987)  
  Rae, J. B. Henry Ford (1969)  
  Richards, George Tilghman The History and Development of Typewriters (1964)  
  Robinson, E. H., and Musson, James (eds.) James Watt and the Steam Revolution: A Documentary History (1969)  
  Rolt, L. T. C. Thomas Telford (1958), George Stephenson (1960), The Railway Revolution: George and Robert Stephenson (1962)  
  Scholderer, Victor Johann Gutenberg: The Inventor of Printing (1963)  
  Schumacher, E. F. Small is Beautiful: A Study of Economics as if People Mattered (1973)  
  Seymour, Raymond B. (ed.) Pioneers in Polymer Science (1989)  
  Taylor, Michael J. History of Helicopters (1984)  
  Wachhorst, W. Thomas Alva Edison: An American Myth (1981)