Edison's

SUBJECT AREA: Architecture and building, Automotive engineering, Electricity, Electronics and information technology, Metallurgy, Photography, film and optics, Public utilities, Recording, Telecommunications

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He was the son of Samuel Edison, who was in the timber business. His schooling was delayed due to scarlet fever until 1855, when he was 8½ years old, but he was an avid reader. By the age of 14 he had a job as a newsboy on the railway from Port Huron to Detroit, a distance of sixty-three miles (101 km). He worked a fourteen-hour day with a stopover of five hours, which he spent in the Detroit Free Library. He also sold sweets on the train and, later, fruit and vegetables, and was soon making a profit of $20 a week. He then started two stores in Port Huron and used a spare freight car as a laboratory. He added a hand-printing press to produce 400 copies weekly of The Grand Trunk Herald, most of which he compiled and edited himself. He set himself to learn telegraphy from the station agent at Mount Clements, whose son he had saved from being run over by a freight car.

At the age of 16 he became a telegraphist at Port Huron. In 1863 he became railway telegraphist at the busy Stratford Junction of the Grand Trunk Railroad, arranging a clock with a notched wheel to give the hourly signal which was to prove that he was awake and at his post! He left hurriedly after failing to hold a train which was nearly involved in a head-on collision. He usually worked the night shift, allowing himself time for experiments during the day. His first invention was an arrangement of two Morse registers so that a high-speed input could be decoded at a slower speed. Moving from place to place he held many positions as a telegraphist. In Boston he invented an automatic vote recorder for Congress and patented it, but the idea was rejected. This was the first of a total of 1180 patents that he was to take out during his lifetime. After six years he resigned from the Western Union Company to devote all his time to invention, his next idea being an improved ticker-tape machine for stockbrokers. He developed a duplex telegraphy system, but this was turned down by the Western Union Company. He then moved to New York.

Edison found accommodation in the battery room of Law's Gold Reporting Company, sleeping in the cellar, and there his repair of a broken transmitter marked him as someone of special talents. His superior soon resigned, and he was promoted with a salary of $300 a month. Western Union paid him $40,000 for the sole rights on future improvements on the duplex telegraph, and he moved to Ward Street, Newark, New Jersey, where he employed a gathering of specialist engineers. Within a year, he married one of his employees, Mary Stilwell, when she was only 16: a daughter, Marion, was born in 1872, and two sons, Thomas and William, in 1876 and 1879, respectively.

He continued to work on the automatic telegraph, a device to send out messages faster than they could be tapped out by hand: that is, over fifty words per minute or so. An earlier machine by Alexander Bain worked at up to 400 words per minute, but was not good over long distances. Edison agreed to work on improving this feature of Bain's machine for the Automatic Telegraph Company (ATC) for $40,000. He improved it to a working speed of 500 words per minute and ran a test between Washington and New York. Hoping to sell their equipment to the Post Office in Britain, ATC sent Edison to England in 1873 to negotiate. A 500-word message was to be sent from Liverpool to London every half-hour for six hours, followed by tests on 2,200 miles (3,540 km) of cable at Greenwich. Only confused results were obtained due to induction in the cable, which lay coiled in a water tank. Edison returned to New York, where he worked on his quadruplex telegraph system, tests of which proved a success between New York and Albany in December 1874. Unfortunately, simultaneous negotiation with Western Union and ATC resulted in a lawsuit.

Alexander Graham Bell was granted a patent for a telephone in March 1876 while Edison was still working on the same idea. His improvements allowed the device to operate over a distance of hundreds of miles instead of only a few miles. Tests were carried out over the 106 miles (170 km) between New York and Philadelphia. Edison applied for a patent on the carbon-button transmitter in April 1877, Western Union agreeing to pay him $6,000 a year for the seventeen-year duration of the patent. In these years he was also working on the development of the electric lamp and on a duplicating machine which would make up to 3,000 copies from a stencil. In 1876–7 he moved from Newark to Menlo Park, twenty-four miles (39 km) from New York on the Pennsylvania Railway, near Elizabeth. He had bought a house there around which he built the premises that would become his "inventions factory". It was there that he began the use of his 200- page pocket notebooks, each of which lasted him about two weeks, so prolific were his ideas. When he died he left 3,400 of them filled with notes and sketches.

Late in 1877 he applied for a patent for a phonograph which was granted on 19 February 1878, and by the end of the year he had formed a company to manufacture this totally new product. At the time, Edison saw the device primarily as a business aid rather than for entertainment, rather as a dictating machine. In August 1878 he was granted a British patent. In July 1878 he tried to measure the heat from the solar corona at a solar eclipse viewed from Rawlins, Wyoming, but his "tasimeter" was too sensitive.

Probably his greatest achievement was "The Subdivision of the Electric Light" or the "glow bulb". He tried many materials for the filament before settling on carbon. He gave a demonstration of electric light by lighting up Menlo Park and inviting the public. Edison was, of course, faced with the problem of inventing and producing all the ancillaries which go to make up the electrical system of generation and distribution-meters, fuses, insulation, switches, cabling—even generators had to be designed and built; everything was new. He started a number of manufacturing companies to produce the various components needed.

In 1881 he built the world's largest generator, which weighed 27 tons, to light 1,200 lamps at the Paris Exhibition. It was later moved to England to be used in the world's first central power station with steam engine drive at Holborn Viaduct, London. In September 1882 he started up his Pearl Street Generating Station in New York, which led to a worldwide increase in the application of electric power, particularly for lighting. At the same time as these developments, he built a 1,300yd (1,190m) electric railway at Menlo Park.

On 9 August 1884 his wife died of typhoid. Using his telegraphic skills, he proposed to 19-year-old Mina Miller in Morse code while in the company of others on a train. He married her in February 1885 before buying a new house and estate at West Orange, New Jersey, building a new laboratory not far away in the Orange Valley.

Edison used direct current which was limited to around 250 volts. Alternating current was largely developed by George Westinghouse and Nicola Tesla, using transformers to step up the current to a higher voltage for long-distance transmission. The use of AC gradually overtook the Edison DC system.

In autumn 1888 he patented a form of cinephotography, the kinetoscope, obtaining film-stock from George Eastman. In 1893 he set up the first film studio, which was pivoted so as to catch the sun, with a hinged roof which could be raised. In 1894 kinetoscope parlours with "peep shows" were starting up in cities all over America. Competition came from the Latham Brothers with a screen-projection machine, which Edison answered with his "Vitascope", shown in New York in 1896. This showed pictures with accompanying sound, but there was some difficulty with synchronization. Edison also experimented with captions at this early date.

In 1880 he filed a patent for a magnetic ore separator, the first of nearly sixty. He bought up deposits of low-grade iron ore which had been developed in the north of New Jersey. The process was a commercial success until the discovery of iron-rich ore in Minnesota rendered it uneconomic and uncompetitive. In 1898 cement rock was discovered in New Village, west of West Orange. Edison bought the land and started cement manufacture, using kilns twice the normal length and using half as much fuel to heat them as the normal type of kiln. In 1893 he met Henry Ford, who was building his second car, at an Edison convention. This started him on the development of a battery for an electric car on which he made over 9,000 experiments. In 1903 he sold his patent for wireless telegraphy "for a song" to Guglielmo Marconi.

In 1910 Edison designed a prefabricated concrete house. In December 1914 fire destroyed three-quarters of the West Orange plant, but it was at once rebuilt, and with the threat of war Edison started to set up his own plants for making all the chemicals that he had previously been buying from Europe, such as carbolic acid, phenol, benzol, aniline dyes, etc. He was appointed President of the Navy Consulting Board, for whom, he said, he made some forty-five inventions, "but they were pigeonholed, every one of them". Thus did Edison find that the Navy did not take kindly to civilian interference.

In 1927 he started the Edison Botanic Research Company, founded with similar investment from Ford and Firestone with the object of finding a substitute for overseas-produced rubber. In the first year he tested no fewer than 3,327 possible plants, in the second year, over 1,400, eventually developing a variety of Golden Rod which grew to 14 ft (4.3 m) in height. However, all this effort and money was wasted, due to the discovery of synthetic rubber.

In October 1929 he was present at Henry Ford's opening of his Dearborn Museum to celebrate the fiftieth anniversary of the incandescent lamp, including a replica of the Menlo Park laboratory. He was awarded the Congressional Gold Medal and was elected to the American Academy of Sciences. He died in 1931 at his home, Glenmont; throughout the USA, lights were dimmed temporarily on the day of his funeral.

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SUBJECT AREA: Photography, film and optics

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Dickson was born in France of English and Scottish parents. As a young man of almost 19 years, he wrote in 1879 to Thomas Edison in America, asking for a job. Edison replied that he was not taking on new staff at that time, but Dickson, with his mother and sisters, decided to emigrate anyway. In 1883 he contacted Edison again, and was given a job at the Goerk Street laboratory of the Edison Electric Works in New York. He soon assumed a position of responsibility as Superintendent, working on the development of electric light and power systems, and also carried out most of the photography Edison required. In 1888 he moved to the Edison West Orange laboratory, becoming Head of the ore-milling department. When Edison, inspired by Muybridge's sequence photographs of humans and animals in motion, decided to develop a motion picture apparatus, he gave the task to Dickson, whose considerable skills in mechanics, photography and electrical work made him the obvious choice. The first experiments, in 1888, were on a cylinder machine like the phonograph, in which the sequence pictures were to be taken in a spiral. This soon proved to be impractical, and work was delayed for a time while Dickson developed a new ore-milling machine. Little progress with the movie project was made until George Eastman's introduction in July 1889 of celluloid roll film, which was thin, tough, transparent and very flexible. Dickson returned to his experiments in the spring of 1891 and soon had working models of a film camera and viewer, the latter being demonstrated at the West Orange laboratory on 20 May 1891. By the early summer of 1892 the project had advanced sufficiently for commercial exploitation to begin. The Kinetograph camera used perforated 35 mm film (essentially the same as that still in use in the late twentieth century), and the kinetoscope, a peep-show viewer, took fifty feet of film running in an endless loop. Full-scale manufacture of the viewers started in 1893, and they were demonstrated on a number of occasions during that year. On 14 April 1894 the first kinetoscope parlour, with ten viewers, was opened to the public in New York. By the end of that year, the kinetoscope was seen by the public all over America and in Europe. Dickson had created the first commercially successful cinematograph system. Dickson left Edison's employment on 2 April 1895, and for a time worked with Woodville Latham on the development of his Panoptikon projector, a projection version of the kinetoscope. In December 1895 he joined with Herman Casier, Henry N.Marvin and Elias Koopman to form the American Mutoscope Company. Casier had designed the Mutoscope, an animated-picture viewer in which the sequences of pictures were printed on cards fixed radially to a drum and were flipped past the eye as the drum rotated. Dickson designed the Biograph wide-film camera to produce the picture sequences, and also a projector to show the films directly onto a screen. The large-format images gave pictures of high quality for the period; the Biograph went on public show in America in September 1896, and subsequently throughout the world, operating until around 1905. In May 1897 Dickson returned to England and set up as a producer of Biograph films, recording, among other subjects, Queen Victoria's Diamond Jubilee celebrations in 1897, Pope Leo XIII in 1898, and scenes of the Boer War in 1899 and 1900. Many of the Biograph subjects were printed as reels for the Mutoscope to produce the "what the butler saw" machines which were a feature of fairgrounds and seaside arcades until modern times. Dickson's contact with the Biograph Company, and with it his involvement in cinematography, ceased in 1911.

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SUBJECT AREA: Automotive engineering, Land transport

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He was the son of an Irish immigrant farmer, William Ford, and the oldest son to survive of Mary Litogot; his mother died in 1876 with the birth of her sixth child. He went to the village school, and at the age of 16 he was apprenticed to Flower brothers' machine shop and then at the Drydock \& Engineering Works in Detroit. In 1882 he left to return to the family farm and spent some time working with a 1 1/2 hp steam engine doing odd jobs for the farming community at $3 per day. He was then employed as a demonstrator for Westinghouse steam engines. He met Clara Jane Bryant at New Year 1885 and they were married on 11 April 1888. Their only child, Edsel Bryant Ford, was born on 6 November 1893.

At that time Henry worked on steam engine repairs for the Edison Illuminating Company, where he became Chief Engineer. He became one of a group working to develop a "horseless carriage" in 1896 and in June completed his first vehicle, a "quadri cycle" with a two-cylinder engine. It was built in a brick shed, which had to be partially demolished to get the carriage out.

Ford became involved in motor racing, at which he was more successful than he was in starting a car-manufacturing company. Several early ventures failed, until the Ford Motor Company of 1903. By October 1908 they had started with production of the Model T. The first, of which over 15 million were built up to the end of its production in May 1927, came out with bought-out steel stampings and a planetary gearbox, and had a one-piece four-cylinder block with a bolt-on head. This was one of the most successful models built by Ford or any other motor manufacturer in the life of the motor car.

Interchangeability of components was an important element in Ford's philosophy. Ford was a pioneer in the use of vanadium steel for engine components. He adopted the principles of Frederick Taylor, the pioneer of time-and-motion study, and installed the world's first moving assembly line for the production of magnetos, started in 1913. He installed blast furnaces at the factory to make his own steel, and he also promoted research and the cultivation of the soya bean, from which a plastic was derived.

In October 1913 he introduced the "Five Dollar Day", almost doubling the normal rate of pay. This was a profit-sharing scheme for his employees and contained an element of a reward for good behaviour. About this time he initiated work on an agricultural tractor, the "Fordson" made by a separate company, the directors of which were Henry and his son Edsel.

In 1915 he chartered the Oscar II, a "peace ship", and with fifty-five delegates sailed for Europe a week before Christmas, docking at Oslo. Their objective was to appeal to all European Heads of State to stop the war. He had hoped to persuade manufacturers to replace armaments with tractors in their production programmes. In the event, Ford took to his bed in the hotel with a chill, stayed there for five days and then sailed for New York and home. He did, however, continue to finance the peace activists who remained in Europe. Back in America, he stood for election to the US Senate but was defeated. He was probably the father of John Dahlinger, illegitimate son of Evangeline Dahlinger, a stenographer employed by the firm and on whom he lavished gifts of cars, clothes and properties. He became the owner of a weekly newspaper, the Dearborn Independent, which became the medium for the expression of many of his more unorthodox ideas. He was involved in a lawsuit with the Chicago Tribune in 1919, during which he was cross-examined on his knowledge of American history: he is reputed to have said "History is bunk". What he actually said was, "History is bunk as it is taught in schools", a very different comment. The lawyers who thus made a fool of him would have been surprised if they could have foreseen the force and energy that their actions were to release. For years Ford employed a team of specialists to scour America and Europe for furniture, artefacts and relics of all kinds, illustrating various aspects of history. Starting with the Wayside Inn from South Sudbury, Massachusetts, buildings were bought, dismantled and moved, to be reconstructed in Greenfield Village, near Dearborn. The courthouse where Abraham Lincoln had practised law and the Ohio bicycle shop where the Wright brothers built their first primitive aeroplane were added to the farmhouse where the proprietor, Henry Ford, had been born. Replicas were made of Independence Hall, Congress Hall and the old City Hall in Philadelphia, and even a reconstruction of Edison's Menlo Park laboratory was installed. The Henry Ford museum was officially opened on 21 October 1929, on the fiftieth anniversary of Edison's invention of the incandescent bulb, but it continued to be a primary preoccupation of the great American car maker until his death.

Henry Ford was also responsible for a number of aeronautical developments at the Ford Airport at Dearborn. He introduced the first use of radio to guide a commercial aircraft, the first regular airmail service in the United States. He also manufactured the country's first all-metal multi-engined plane, the Ford Tri-Motor.

Edsel became President of the Ford Motor Company on his father's resignation from that position on 30 December 1918. Following the end of production in May 1927 of the Model T, the replacement Model A was not in production for another six months. During this period Henry Ford, though officially retired from the presidency of the company, repeatedly interfered and countermanded the orders of his son, ostensibly the man in charge. Edsel, who died of stomach cancer at his home at Grosse Point, Detroit, on 26 May 1943, was the father of Henry Ford II. Henry Ford died at his home, "Fair Lane", four years after his son's death.

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SUBJECT AREA: Photography, film and optics, Recording

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Lauste was a prolific inventor who as a 22-year-old had more than fifty patents to his name. He joined Edison's West Orange Laboratory as Assistant to W.K.L. Dickson in 1887; he was soon involved in the development of early motion pictures, beginning an association with the cinema that was to dominate the rest of his working life. He left Edison in 1892 to pursue an interest in petrol engines, but within two years he returned to cinematography, where, in association with Major Woodville Latham, he introduced small but significant improvements to film-projection systems. In 1900 an interest in sound recording, dating back to his early days with Edison, led Lauste to begin exploring the possibility of recording sound photographically on film alongside the picture. In 1904 he moved to England, where he continued his experiments, and by 1907 he had succeeded in photographing a sound trace and picture simultaneously, each image occupying half the width of the film.

Despite successful demonstrations of Lauste's system on both sides of the Atlantic, he enjoyed no commercial success. Handicapped by lack of capital, his efforts were finally brought to an end by the First World War. In 1906 Lauste had filed a patent for his sound-on-film system, which has been described by some authorities as the master patent for talking pictures. Although this claim is questionable, he was the first to produce a practicable scund-on-film system and establish the basic principles that were universally followed until the introduction of magnetic sound.

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SUBJECT AREA: Electricity, Electronics and information technology, Photography, film and optics

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Paul was educated at the City of London School and Finsbury Technical College. He worked first for a short time in the Bell Telephone Works in Antwerp, Belgium, and then in the electrical instrument shop of Elliott Brothers in the Strand until 1891, when he opened an instrument-making business at 44 Hatton Garden, London. He specialized in the design and manufacture of electrical instruments, including the Ayrton Mather galvanometer. In 1902, with a purpose-built factory, he began large batch production of his instruments. He also opened a factory in New York, where uncalibrated instruments from England were calibrated for American customers. In 1903 Paul introduced the Unipivot galvanometer, in which the coil was supported at the centre of gravity of the moving system on a single pivot. The pivotal friction was less than in a conventional instrument and could be used without accurate levelling, the sensitivity being far beyond that of any pivoted galvanometer then in existence.

In 1894 Paul was asked by two entrepreneurs to make copies of Edison's kinetoscope, the pioneering peep-show moving-picture viewer, which had just arrived in London. Discovering that Edison had omitted to patent the machine in England, and observing that there was considerable demand for the machine from show-people, he began production, making six before the end of the year. Altogether, he made about sixty-six units, some of which were exported. Although Edison's machine was not patented, his films were certainly copyrighted, so Paul now needed a cinematographic camera to make new subjects for his customers. Early in 1895 he came into contact with Birt Acres, who was also working on the design of a movie camera. Acres's design was somewhat impractical, but Paul constructed a working model with which Acres filmed the Oxford and Cambridge Boat Race on 30 March, and the Derby at Epsom on 29 May. Paul was unhappy with the inefficient design, and developed a new intermittent mechanism based on the principle of the Maltese cross. Despite having signed a ten-year agreement with Paul, Acres split with him on 12 July 1895, after having unilaterally patented their original camera design on 27 May. By the early weeks of 1896, Paul had developed a projector mechanism that also used the Maltese cross and which he demonstrated at the Finsbury Technical College on 20 February 1896. His Theatrograph was intended for sale, and was shown in a number of venues in London during March, notably at the Alhambra Theatre in Leicester Square. There the renamed Animatographe was used to show, among other subjects, the Derby of 1896, which was won by the Prince of Wales's horse "Persimmon" and the film of which was shown the next day to enthusiastic crowds. The production of films turned out to be quite profitable: in the first year of the business, from March 1896, Paul made a net profit of £12,838 on a capital outlay of about £1,000. By the end of the year there were at least five shows running in London that were using Paul's projectors and screening films made by him or his staff.

Paul played a major part in establishing the film business in England through his readiness to sell apparatus at a time when most of his rivals reserved their equipment for sole exploitation. He went on to become a leading producer of films, specializing in trick effects, many of which he pioneered. He was affectionately known in the trade as "Daddy Paul", truly considered to be the "father" of the British film industry. He continued to appreciate fully the possibilities of cinematography for scientific work, and in collaboration with Professor Silvanus P.Thompson films were made to illustrate various phenomena to students.

Paul ended his involvement with film making in 1910 to concentrate on his instrument business; on his retirement in 1920, this was amalgamated with the Cambridge Instrument Company. In his will he left shares valued at over £100,000 to form the R.W.Paul Instrument Fund, to be administered by the Institution of Electrical Engineers, of which he had been a member since 1887. The fund was to provide instruments of an unusual nature to assist physical research.

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BC / GW

SUBJECT AREA: Architecture and building, Electricity, Land transport, Railways and locomotives

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Graduating from the United States Naval Academy, Annapolis, in 1878, Sprague served at sea and with various shore establishments. In 1883 he resigned from the Navy and obtained employment with the Edison Company; but being convinced that the use of electricity for motive power was as important as that for illumination, in 1884 he founded the Sprague Electric Railway and Motor Company. Sprague began to develop reliable and efficient motors in large sizes, marketing 15 hp (11 kW) examples by 1885. He devised the method of collecting current by using a wooden, spring-loaded rod to press a roller against the underside of an overhead wire. The installation by Sprague in 1888 of a street tramway on a large scale in Richmond, Virginia, was to become the prototype of the universally adopted trolley system with overhead conductor and the beginning of commercial electric traction. Following the success of the Richmond tramway the company equipped sixty-seven other railways before its merger with Edison General Electric in 1890. The Sprague traction motor supported on the axle of electric streetcars and flexibly mounted to the bogie set a pattern that was widely adopted for many years.

Encouraged by successful experiments with multiple-sheave electric elevators, the Sprague Elevator Company was formed and installed the first set of high-speed passenger cars in 1893–4. These effectively displaced hydraulic elevators in larger buildings. From experience with control systems for these, he developed his system of multiple-unit control for electric trains, which other engineers had considered impracticable. In Sprague's system, a master controller situated in the driver's cab operated electrically at a distance the contactors and reversers which controlled the motors distributed down the train. After years of experiment, Sprague's multiple-unit control was put into use for the first time in 1898 by the Chicago South Side Elevated Railway: within fifteen years multiple-unit operation was used worldwide.

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SUBJECT AREA: Recording

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He manufactured "philosophical devices" in Cambridge, Massachusetts, and was approached by Alexander Graham Bell in connection with the construction of toys using sound recordings. A more formal co-operation was agreed, and after Bell's receipt of the French Volta prize in 1880 he financed the Volta Laboratory Association in Washington, DC. He founded this in 1881 together with a cousin and Tainter to develop a practical sound-recording and -reproducing system. Another area that was developed was the transmission of sound by means of modulated light and reception via a selenium cell.

The advances in sound recording and reproduction were very positive, and T.A. Edison was approached in mid-1885 in order to establish co-operation in the further development of a cylinder instrument. In early 1886 the Volta Graphophone Company was incorporated in Virginia, and an experimental laboratory was established in Washington, DC. The investors were connected with the secretarial services at the House of Representatives and needed the development for increasing efficiency in debate reporting. In mid-1887 Edison, against the advice of his collaborators, declined co-operation and went ahead on his own. There is no doubt that Tainter's skill in developing functional equipment and the speed with which he was able to work in the crucial years provoked other developments in the field, in particular the perfection of the Edison phonograph and the development of the disc record by Berliner.

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SUBJECT AREA: Electricity

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While at the technical institute in Graz, Austria, Tesla's attention was drawn to the desirability of constructing a motor without a commutator. He considered the sparking between the commutator and brushes of the Gramme machine when run as a motor a serious defect. In 1881 he went to Budapest to work on the telegraph system and while there conceived the principle of the rotating magnetic field, upon which all polyphase induction motors are based. In 1882 Tesla moved to Paris and joined the Continental Edison Company. After building a prototype of his motor he emigrated to the United States in 1884, becoming an American citizen in 1889. He left Edison and founded an independent concern, the Tesla Electric Company, to develop his inventions.

The importance of Tesla's first patents, granted in 1888 for alternating-current machines, cannot be over-emphasized. They covered a complete polyphase system including an alternator and induction motor. Other patents included the polyphase transformer, synchronous motor and the star connection of three-phase machines. These were to become the basis of the whole of the modern electric power industry. The Westinghouse company purchased the patents and marketed Tesla motors, obtaining in 1893 the contract for the Niagara Falls two-phase alternators driven by 5,000 hp (3,700 kW) water turbines.

After a short period with Westinghouse, Tesla resigned to continue his research into high-frequency and high-voltage phenomena using the Tesla coil, an air-cored transformer. He lectured in America and Europe on his high-frequency devices, enjoying a considerable international reputation. The name "tesla" has been given to the SI unit of magnetic-flux density. The induction motor became one of the greatest advances in the industrial application of electricity. A claim for priority of invention of the induction motor was made by protagonists of Galileo Ferraris (1847–1897), whose discovery of rotating magnetic fields produced by alternating currents was made independently of Tesla's. Ferraris demonstrated the phenomenon but neglected its exploitation to produce a practical motor. Tesla himself failed to reap more than a small return on his work and later became more interested in scientific achievement than commercial success, with his patents being infringed on a wide scale.

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SUBJECT AREA: Photography, film and optics

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Carbutt emigrated in 1853 from England to the United States, where he remained for the rest of his life. He began working as a photographer in Chicago, where he soon earned a considerable reputation and became the official photographer for the Canadian Pacific Railway. In 1870 he purchased the American rights of Woodbury's photomechanical printing process and established a business to produce Woodburytypes in Philadelphia. In 1879 Carbutt set up the first successful gelatine halide dry-plate factory in America. A year later he was elected first President of the Photographers' Association of America. He began experimenting with flexible film supports in 1884 and was the first to produce satisfactory flat films on celluloid commercially. The first kinetoscope film strips used by Thomas Edison were supplied by Carbutt. Carbutt's celluloid films were exported to Europe, where nothing comparable was available at the time. He was also a pioneer manufacturer of orthochromatic plates, X-ray plates and photographic colour filters.

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SUBJECT AREA: Photography, film and optics, Recording, Telecommunications

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He received no formal education, but was brought up by his father, a distinguished teacher and philosopher. He dabbled in diverse subjects (modern and ancient languages, mathematics, drawing) in 1856–60 when he became an instructor at the institute of the Deaf-Mute at Paris. He became a prolific inventor and poet and took part in artistic life in Paris. In the 1867 Exposition Universelle in Paris, Cros contributed a facsimile telegraph; he deposited with the Académie des Sciences a sealed text on photography which was not opened until 1876. In the meantime he published a small text on a general solution of the problem of colour photography which appeared almost simultaneously with a similar publication by Louis Ducos du Hauron and which gave rise to bitter discussions over priority. He deposited a sealed paper on 18 April 1877 concerning his concept of apparatus for recording and reproduction of sound which he called the paléophone. When it was opened on 3 December 1877 it was not known that T.A. Edison was already active in this field: Cros is considered the conceptual founder of reproducible sound, whereas Edison was the first "to reduce to practice", which is one of the US criteria for patentability.

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SUBJECT AREA: Electricity, Electronics and information technology, Public utilities

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After attending Owens College, Manchester, Hopkinson was admitted to Trinity College, Cambridge, in 1867 to read for the Mathematical Tripos. An appointment in 1872 with the lighthouse department of the Chance Optical Works in Birmingham directed his attention to electrical engineering. His most noteworthy contribution to lighthouse engineering was an optical system to produce flashing lights that distinguished between individual beacons. His extensive researches on the dielectric properties of glass were recognized when he was elected to a Fellowship of the Royal Society at the age of 29. Moving to London in 1877 he became established as a consulting engineer at a time when electricity supply was about to begin on a commercial scale. During the remainder of his life, Hopkinson's researches resulted in fundamental contributions to electrical engineering practice, dynamo design and alternating current machine theory. In making a critical study of the Edison dynamo he developed the principle of the magnetic circuit, a concept also arrived at by Gisbert Kapp around the same time. Hopkinson's improvement of the Edison dynamo by reducing the length of the field magnets almost doubled its output. In 1890, in addition to-his consulting practice, Hopkinson accepted a post as the first Professor of Electrical Engineering and Head of the Siemens laboratory recently established at King's College, London. Although he was not involved in lecturing, the position gave him the necessary facilities and staff and student assistance to continue his researches. Hopkinson was consulted on many proposals for electric traction and electricity supply, including schemes in London, Manchester, Liverpool and Leeds. He also advised Mather and Platt when they were acting as contractors for the locomotives and generating plant for the City and South London tube railway. As early as 1882 he considered that an ideal method of charging for the supply of electricity should be based on a two-part tariff, with a charge related to maximum demand together with a charge for energy supplied. Hopkinson was one the foremost expert witnesses of his day in patent actions and was himself the patentee of over forty inventions, of which the three-wire system of distribution and the series-parallel connection of traction motors were his most successful. Jointly with his brother Edward, John Hopkinson communicated the outcome of his investigations to the Royal Society in a paper entitled "Dynamo Electric Machinery" in 1886. In this he also described the later widely used "back to back" test for determining the characteristics of two identical machines. His interest in electrical machines led him to more fundamental research on magnetic materials, including the phenomenon of recalescence and the disappearance of magnetism at a well-defined temperature. For his work on the magnetic properties of iron, in 1890 he was awarded the Royal Society Royal Medal. He was a member of the Alpine Club and a pioneer of rock climbing in Britain; he died, together with three of his children, in a climbing accident.

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SUBJECT AREA: Broadcasting, Electricity, Electronics and information technology, Telecommunications

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As a young man, Kennelly worked as office boy for a London engineering society, as an electrician and on a cable-laying ship. In 1887 he went to work for Thomas Edison at West Orange, New Jersey, USA, becoming his chief assistant. In 1894, with Edwin J.Houston, he formed the Philadelphia company of Houston and Kennelly, but eight years later he took up the Chair of Electrical Engineering at Harvard, a post he held until his retirement in 1930. In 1902 he noticed that the radio signals received by Marconi in Nova Scotia from the transmitter in England were stronger than predicted and postulated a reflecting ionized layer in the upper atmosphere. Almost simultaneously the same prediction was made in England by Heaviside, so the layer became known as the Kennelly-Heaviside layer. Throughout most of his working life Kennelly was concerned with the application of mathematical techniques, particularly the use of complex theory, to the analysis of electrical circuits. With others he also contributed to an understanding of the high-frequency skin-effect in conductors.

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SUBJECT AREA: Recording

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He was the descendant of a Scottish family who emigrated to France in 1688. He trained as a printer and later became a proof corrector in printing houses catering predominantly for scientific publishers. He became interested in shorthand systems and eventually turned his interest to making a permanent record of sounds in air. At the time it was already known (Young, Duhamel, Wertheim) to record vibrations of bodies. He made a theoretical study and deposited under sealed wrapper a note in the Académie des Sciences on 26 January 1857. He approached the scientific instrument maker Froment and was able to pay for the manufacture of one instrument due to support from the Société d'Encouragement à l'Industrie Nationale. This funding body obtained a positive report from the physicist Lissajous on 6 January 1858. A new model phonautograph was constructed in collaboration with the leading scientific instrument maker in Paris at the time, Rudolph Koenig, and a contract was signed in 1859. The instrument was a success, and Koenig published a collection of traces in 1864.

Although the membrane was parallel to the rotating surface, a primitive lever system generated lateral movements of a bristle which scratched curves in a thin layer of lampblack on the rotating surface. The curves were not necessarily representative of the vibrations in the air. Scott did not imagine the need for reproducing a recorded sound; rather, his intention was to obtain a trace that would lend itself to mathematical analysis and visual recognition of sounds. Obviously the latter did not require the same degree of linearity as the former. When Scott learned that similar apparatus had been built independently in the USA, he requested that his sealed wrapper be opened on 15 July 1861 in order to prove his scientific priority. The contract with Koenig left Scott without influence over his instrument, and eventually he became convinced that everyone else, including Edison in the end, had stolen his invention. Towards the end of his life he became interested mainly in the history of printing, and he was involved in the publishing of a series of books about books.

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SUBJECT AREA: Electricity

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Thomson accompanied his parents to Philadelphia in 1858; he received his education at the Central High School there, and afterwards remained as a teacher of chemistry. At this time he constructed several dynamos after studying their design, and was invited by the Franklin Institute to give lectures on the subject. After observing an arc-lighting system operating commercially in Paris in 1878, he collaborated with Edwin J. Houston, a senior colleague at the Central High School, in working out the details of such a system. An automatic regulating device was designed which, by altering the position of the brushes on the dynamo commutator, maintained a constant current irrespective of the number of lamps in use. To overcome the problem of commutation at the high voltages necessary to operate up to forty arc lamps in a series circuit, Thomson contrived a centrifugal blower which suppressed sparking. The resulting system was efficient and reliable with low operating costs. Thomson's invention of the motor meter in 1882 was the first of many such instruments for the measurement of electrical energy. In 1886 he invented electric resistance welding using low-voltage alternating current derived from a transformer of his own design. Thomson's work is recorded in his technical papers and in the 700plus patents granted for his inventions.

The American Electric Company, founded to exploit the Thomson patents, later became the Thomson-Houston Company, which was destined to be a leader in the electrical manufacturing industry. They entered the field of electric power in 1887, supplying railway equipment and becoming a major innovator of electric railways. Thomson-Houston and Edison General Electric were consolidated to form General Electric in 1892. Thomson remained associated with this company throughout his career.

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SUBJECT AREA: Broadcasting, Electronics and information technology, Recording

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He received his education at Dulwich College and in 1922 graduated with a BSc from University College, London. He had an early interest in the application of valve amplifiers, and after graduating he was employed by J.E.Hough, Edison Bell Works, to develop a line of radio-receiving equipment. However, he became interested in the mechanical (and later electrical) side of recording and from 1925 developed principles and equipment. In particular he developed capacitor microphones, not only for in-house work but also commercially, until the mid-1930s. The Edison Bell company did not survive the Depression and closed in 1933. Voigt founded his own company, Voigt Patents Ltd, concentrating on loudspeakers for cinemas and developing horn loudspeakers for domestic use. During the Second World War he continued to develop loudspeaker units and gramophone pick-ups, and in 1950 he emigrated to Toronto, Canada, but his company closed. Voigt taught electronics, and from 1960 to 1969 he was employed by the Radio Regulations Laboratory in Ottawa. After retirement he worked with theoretical cosmology and fundamental interactions.

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SUBJECT AREA: Electricity, Land transport, Railways and locomotives, Telecommunications

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He was first apprenticed in Columbus as a machinist and blacksmith. In 1872 he moved to Missouri, where he was engaged as a fireman and then engine-driver on the Iron Mountain Railroad. In his spare time he devoted much time to the study of electrical engineering. In 1878 he went to sea for two years as engineer on a British vessel. He returned to Ohio, taking up his previous occupation as engine-driver, and in 1884 he achieved his first patent, for a locomotive firebox. However, the drive towards things electrical was too strong and he set up the Woods Electric Company in Cincinnati, Ohio, to develop and market electrical inventions. Woods gained some fame as an inventor and became known as the "black Edison ". His first device, a telephone transmitter, was patented in December 1884 but faced stiff competition from similar inventions by Alexander Graham Bell and others. The following year he patented a device for transmitting messages in Morse code or by voice that was valuable enough to be bought up by the Bell Telephone Company. A stream of inventions followed, particularly for railway telegraph and electrical systems. This brought him into conflict with Edison, who was working in the same field. The US Patent Office ruled in Woods's favour; as a result of the ensuing publicity, one newspaper hailed Woods as the "greatest electrician in the world". In 1890 Woods moved to New York, where the opportunities for an electrical engineer seemed more favourable. He turned his attention to inventions that would improve the tram-car. One device enabled electric current to be transferred to the car with less friction than previously, incorporating a grooved wheel known as a "troller", whence came the popular term "trolley car".

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SUBJECT AREA: Photography, film and optics

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Born of English parents and educated in Paris, Acres travelled to England in the 1880s. He worked for the photographic manufacturing firm Elliott \& Co. in Barnet, near London, and became the Manager. He became well known through his frequent lectures, demonstrations and articles in the photographic press. The appearance of the Edison kinetoscope in 1893 seems to have aroused his interest in the recording and reproduction of movement.

At the beginning of 1895 he took his idea for a camera to Robert Paul, an instrument maker, and they collaborated on the building of a working camera, which Acres used to record the Oxford and Cambridge Boat Race on 30 March 1895. He filmed the Derby at Epsom on 29 May and the opening of the Kiel Canal in June, as well as ten other subjects for the kinetoscope, which were sold by Paul. Acres's association with Paul ended in July 1895. Acres had patented the camera design, the Kinetic Lantern, on 27 May 1895 and then went on to design a projector with which he gave the first successful presentation of projected motion pictures to take place in Britain, at the Royal Photographic Society's meeting on 14 January 1896. At the end of the month Acres formed his own business, the Northern Photographic Company, to supply film stock, process and print exposed film, and to make finished film productions.

His first shows to the public, using the renamed Kineopticon projector, started in Piccadilly Circus on 21 March 1896. He later toured the country with his show. He was honoured with a Royal Command Performance at Marlborough House on 21 July 1896 before members of the royal family. Although he made a number of films for his own use, they and his equipment were used only for his own demonstrations. His last contribution to cinematography was the design and patenting in 1898 of the first low-cost system for amateur use, the Birtac, which was first shown on 25 January 1899 and marketed in May of that year. It used half-width film, 17.5 mm wide, and the apparatus served as camera, printer and projector.

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SUBJECT AREA: Broadcasting, Electricity, Electronics and information technology, Telecommunications

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After education in Sweden at the High School and University of Lund and the Royal Institution of Technology in Stockholm, Alexanderson took a postgraduate course at the Berlin-Charlottenburg Engineering College. In 1901 he began work for the Swedish C \& C Electric Company, joining the General Electric Company, Schenectady, New York, the following year. There, in 1906, together with Fessenden, he developed a series of high-power, high-frequency alternators, which had a dramatic effect on radio communications and resulted in the first real radio broadcast. His early interest in television led to working demonstrations in his own home in 1925 and at the General Electric laboratories in 1927, and to the first public demonstration of large-screen (7 ft (2.13 m) diagonal) projection TV in 1930. Another invention of significance was the "amplidyne", a sensitive manufacturing-control system subsequently used during the Second World War for controlling anti-aircraft guns. He also contributed to developments in electric propulsion and radio aerials.

He retired from General Electric in 1948, but continued television research as a consultant for the Radio Corporation of America (RCA), filing his 321st patent in 1955.

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See also: INDEX BY SUBJECT AREA

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Adam, Robert

Albert, Prince Consort

Anthemios of Tralles

Apollonius of Perga

Arup, Sir Ove

Aspdin, Joseph

Barry, Sir Charles

Behrens, Peter

Bogardus, James

Breuer, Marcel Lajos

Brodrick, Cuthbert

Brunelleschi, Filippo

Bunning, James Bunstone

Coade, Eleanor

Coignet, François

Cubitt, Thomas

Edison, Thomas Alva

Fox, Sir Charles

Freyssinet, Eugène

Frost, James

Fuller, Richard Buckminster

Garnier, Tony

Gilbert, Cass

Gropius, Walter Adolf

Hennébique, François

Hero of Alexandria

Hodgkinson, Eaton

Holabird, William

Hopper, Thomas

Jeanneret, Charles-Edouard

Jenney, William Le Baron

Johnson, Isaac Charles

Johnston, William J.

Lascelles, William

Leonardo da Vinci

Lever, William Hesketh

Li Jie

Loos, Adolf

Lubetkin, Berthold

Mansart, Nicolas François

Mendelsohn, Erich

Mengoni, Giuseppe

Mies van der Rohe, Ludwig

Monier, Joseph

Montferrand, Auguste Ricard de

Mylne, Robert

Nash, John

Nervi, Pier Luigi

Otis, Elijah Graves

Parker, James

Paxton, Sir Joseph

Perkins, Jacob

Perret, Auguste

Poelzig, Hans

Ransome, Frederick

Rickman, Thomas

Rondelet, Jean-Baptiste

Salt, Sir Titus

Sant'Elia, Antonio

Smirke, Sydney

Soane, Sir John

Sprague, Frank Julian

Sullivan, Louis Henry

Terragni, Giuseppe

Town, Ithiel

Villard de Honnecourt

Vitruvius Pollio

Walter, Thomas Ustick

Wren, Sir Christopher

Wright, Frank Lloyd

SUBJECT AREA: Broadcasting, Electronics and information technology, Telecommunications

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Interested from childhood in anything mechanical, as a teenager Armstrong constructed a variety of wireless equipment in the attic of his parents' home, including spark-gap transmitters and receivers with iron-filing "coherer" detectors capable of producing weak Morse-code signals. In 1912, while still a student of engineering at Columbia University, he applied positive, i.e. regenerative, feedback to a Lee De Forest triode amplifier to just below the point of oscillation and obtained a gain of some 1,000 times, giving a receiver sensitivity very much greater than hitherto possible. Furthermore, by allowing the circuit to go into full oscillation he found he could generate stable continuous-waves, making possible the first reliable CW radio transmitter. Sadly, his claim to priority with this invention, for which he filed US patents in 1913, the year he graduated from Columbia, led to many years of litigation with De Forest, to whom the US Supreme Court finally, but unjustly, awarded the patent in 1934. The engineering world clearly did not agree with this decision, for the Institution of Radio Engineers did not revoke its previous award of a gold medal and he subsequently received the highest US scientific award, the Franklin Medal, for this discovery.

During the First World War, after some time as an instructor at Columbia University, he joined the US Signal Corps laboratories in Paris, where in 1918 he invented the superheterodyne, a major contribution to radio-receiver design and for which he filed a patent in 1920. The principle of this circuit, which underlies virtually all modern radio, TV and radar reception, is that by using a local oscillator to convert, or "heterodyne", a wanted signal to a lower, fixed, "intermediate" frequency it is possible to obtain high amplification and selectivity without the need to "track" the tuning of numerous variable circuits.

Returning to Columbia after the war and eventually becoming Professor of Electrical Engineering, he made a fortune from the sale of his patent rights and used part of his wealth to fund his own research into further problems in radio communication, particularly that of receiver noise. In 1933 he filed four patents covering the use of wide-band frequency modulation (FM) to achieve low-noise, high-fidelity sound broadcasting, but unable to interest RCA he eventually built a complete broadcast transmitter at his own expense in 1939 to prove the advantages of his system. Unfortunately, there followed another long battle to protect and exploit his patents, and exhausted and virtually ruined he took his own life in 1954, just as the use of FM became an established technique.

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