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   Portugal's oldest and once its most prestigious university. As one of Europe's oldest seats of learning, the University of Coimbra and its various roles have a historic importance that supersedes merely the educational. For centuries, the university formed and trained the principal elites and professions that dominated Portugal. For more than a century, certain members of its faculty entered the central government in Lisbon. A few, such as law professor Afonso Costa, mathematics instructor Sidônio Pais, anthropology professor Bernardino Machado, and economics professor Antônio de Oliveira Salazar, became prime ministers and presidents of the republic. In such a small country, with relatively few universities until recently, Portugal counted Coimbra's university as the educational cradle of its leaders and knew its academic traditions as an intimate part of national life.

   Established in 1290 by King Dinis, the university first opened in Lisbon but was moved to Coimbra in 1308, and there it remained. University buildings were placed high on a hill, in a position that

   physically dominates Portugal's third city. While sections of the medieval university buildings are present, much of what today remains of the old University of Coimbra dates from the Manueline era (1495-1521) and the 17th and 18th centuries. The main administration building along the so-called Via Latina is baroque, in the style of the 17th and 18th centuries. Most prominent among buildings adjacent to the central core structures are the Chapel of São Miguel, built in the 17th century, and the magnificent University Library, of the era of wealthy King João V, built between 1717 and 1723. Created entirely by Portuguese artists and architects, the library is unique among historic monuments in Portugal. Its rare book collection, a monument in itself, is complemented by exquisite gilt wood decorations and beautiful doors, windows, and furniture. Among visitors and tourists, the chapel and library are the prime attractions to this day.

   The University underwent important reforms under the Pombaline administration (1750-77). Efforts to strengthen Coimbra's position in advanced learning and teaching by means of a new curriculum, including new courses in new fields and new degrees and colleges (in Portugal, major university divisions are usually called "faculties") often met strong resistance. In the Age of the Discoveries, efforts were made to introduce the useful study of mathematics, which was part of astronomy in that day, and to move beyond traditional medieval study only of theology, canon law, civil law, and medicine. Regarding even the advanced work of the Portuguese astronomer and mathematician Pedro Nunes, however, Coimbra University was lamentably slow in introducing mathematics or a school of arts and general studies. After some earlier efforts, the 1772 Pombaline Statutes, the core of the Pombaline reforms at Coimbra, had an impact that lasted more than a century. These reforms remained in effect to the end of the monarchy, when, in 1911, the First Republic instituted changes that stressed the secularization of learning. This included the abolition of the Faculty of Theology.

   Elaborate, ancient traditions and customs inform the faculty and student body of Coimbra University. Tradition flourishes, although some customs are more popular than others. Instead of residing in common residences or dormitories as in other countries, in Coimbra until recently students lived in the city in "Republics," private houses with domestic help hired by the students. Students wore typical black academic gowns. Efforts during the Revolution of 25 April 1974 and aftermath to abolish the wearing of the gowns, a powerful student image symbol, met resistance and generated controversy. In romantic Coimbra tradition, students with guitars sang characteristic songs, including Coimbra fado, a more cheerful song than Lisbon fado, and serenaded other students at special locations. Tradition also decreed that at graduation graduates wore their gowns but burned their school (or college or subject) ribbons ( fitas), an important ceremonial rite of passage.

   The University of Coimbra, while it underwent a revival in the 1980s and 1990s, no longer has a virtual monopoly over higher education in Portugal. By 1970, for example, the country had only four public and one private university, and the University of Lisbon had become more significant than ancient Coimbra. At present, diversity in higher education is even more pronounced: 12 private universities and 14 autonomous public universities are listed, not only in Lisbon and Oporto, but at provincial locations. Still, Coimbra retains an influence as the senior university, some of whose graduates still enter national government and distinguished themselves in various professions.

   An important student concern at all institutions of higher learning, and one that marked the last half of the 1990s and continued into the next century, was the question of increased student fees and tuition payments (in Portuguese, propinas). Due to the expansion of the national universities in function as well as in the size of student bodies, national budget constraints, and the rising cost of education, the central government began to increase student fees. The student movement protested this change by means of various tactics, including student strikes, boycotts, and demonstrations. At the same time, a growing number of private universities began to attract larger numbers of students who could afford the higher fees in private institutions, but who had been denied places in the increasingly competitive and pressured public universities.

   Traditionally, Portugal has been a country with a history of emigration to foreign lands, as well as to the overseas empire. During the early centuries of empire, only relatively small numbers of Portuguese emigrated to reside permanently in its colonies. After the establishment of the second, largely Brazilian empire in the 17th century, however, greater numbers of Portuguese left to seek their fortunes outside Europe. It was only toward the end of the 19th century, however, that Portuguese emigration became a mass movement, at first, largely to Brazil. While Portuguese-speaking Brazil was by far the most popular destination for the majority of Portuguese emigrants in early modern and modern times, after 1830, the United States and later Venezuela also became common destinations.

   Portuguese emigration patterns have changed in the 20th century and, as the Portuguese historian and economist Oliveira Martins wrote before the turn of the century, Portuguese emigration rates are a kind of national barometer. Crises and related social, political, and economic conditions within Portugal, as well as the presence of established emigrant communities in various countries, emigration laws, and the world economy have combined to shape emigration rates and destinations.

   After World War II, Brazil no longer remained the favorite destination of the majority of Portuguese emigrants who left Portugal to improve their lives and standards of living. Beginning in the 1950s, and swelling into a massive stream in the 1960s and into the 1970s, most Portuguese emigrated to find work in France and, after the change in U.S. immigration laws in the mid-1960s, a steady stream went to North America, including Canada. The emigration figures here indicate that the most intensive emigration years coincided with excessive political turmoil and severe draft (army conscription) laws during the First Republic (1912 was the high point), that emigration dropped during World Wars I and II and during economic downturns such as the Depression, and that the largest flow of Portuguese emigration in history occurred after the onset of the African colonial wars (1961) and into the 1970s, as Portuguese sought emigration as a way to avoid conscription or assignment to Africa.

   1887 17,000

   1900ca. 17,000 (mainly to Brazil)

   1910 39,000

   1912 88,000 (75,000 of these to Brazil)

   1930ca. 30,000 (Great Depression)

   1940ca. 8,800

   1950 41,000

   1955 57,000

   1960 67,000

   1965 131,000

   1970 209,000

    Portuguese Emigration Overseas ( figures rounded off; does not include illegal emigration)

   Despite considerable efforts by Lisbon to divert the stream of emigrants from Brazil or France to the African territories of Angola and Mozambique, this colonization effort failed, and most Portuguese who left Portugal preferred the better pay and security of jobs in France and West Germany or in the United States, Venezuela, and Brazil, where there were more deeply rooted Portuguese emigrant communities. At the time of the Revolution of 25 April 1974, when the military coup in Lisbon signaled the beginning of pressures for the Portuguese settlers to leave Africa, the total number of Portuguese resident in the two larger African territories amounted to about 600,000. In modern times, nonimperial Portuguese emigration has prevailed over imperial emigration and has had a significant impact on Portugal's annual budget (due to emigrants' remittances), the political system (since emigrants have a degree of absentee voting rights), investment and economy, and culture.

   A total of 4 million Portuguese reside and work outside Portugal as of 2009, over one-third of the country's continental and island population. It has also been said that more Portuguese of Azorean descent reside outside the Azores than in the Azores. The following statistics reflect the pattern of Portuguese emigrant communities in the world outside the mother country.

   Overseas Portuguese Communities Population Figures by Country of Residence ( estimates for 2002)

   Brazil 1,000,000

   France 650,000

   S. Africa 600,000

   USA 500,000

   Canada 400,000

   Venezuela 400,000

   W. Europe 175,000 (besides France and Germany)

   Germany 125,000

   Britain (UK) 60,000 (including Channel Islands)

   Lusophone Africa 50,000

   Australia 50,000

   Total: 4,010,000 (estimate)

SUBJECT AREA: Aerospace

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In 1915 William E.Boeing and his friend Commander Conrad Westervelt decided that they could improve on the aeroplanes then being produced in the United States. Boeing was a prominent Seattle businessman with interests in land and timber, while Westervelt was an officer in the US Navy. They bought a Martin Model T float-plane in order to gain some experience and then produced their own design, the B \& W, which first flew in June 1916. Westervelt was transferred to the East, leaving Boeing to continue the production of the B \& W floatplanes, for which purpose he set up the Pacific Aero Products Company. On 26 April 1917 this became the Boeing Airplane Company, which prospered following the US involvement in the First World War.

In March 1919 Boeing and Edward Hubbard inaugurated the world's first international airmail service between Seattle and Vancouver, British Columbia, Canada. The Boeing Company then had to face the slump in aircraft manufacturing after the war: they survived, and by 1922 they had started producing a successful series of fighters while continuing to develop their flying-boat and floatplane designs. Boeing set up the Boeing Air Transport Corporation to tender for lucrative airmail contracts and then produced aircraft which could out-perform those of his rivals. The company went from strength to strength and by the end of the 1920s a huge conglomerate had been built up: the United Aircraft and Transport Corporation. They produced an advanced high-speed monoplane mailplane, the model 200 Monomail in 1930, which saw the birth of a new era of Boeing designs.

The Wall Street crash of 1929 and legislation in 1934, which banned any company from both building aeroplanes and running an airline, were setbacks which the Boeing Airplane Company overcame, moving ahead to become world leaders. William E.Boeing decided that it was time he retired, but he returned to work during the Second World War.

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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: Textiles

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James Hargreaves was first a carpenter and then a hand-loom weaver at Stanhill, Blackburn, probably making Blackburn Checks or Greys from linen warps and cotton weft. An invention ascribed to him doubled production in the preparatory carding process before spinning. Two or three cards were nailed to the same stock and the upper one was suspended from the ceiling by a cord and counterweight. Around 1762 Robert Peel (1750–1830) sought his assistance in constructing a carding engine with cylinders that may have originated with Daniel Bourn, but this was not successful. In 1764, inspired by seeing a spinning wheel that continued to revolve after it had been knocked over accidentally, Hargreaves invented his spinning jenny. The first jennies had horizontal wheels and could spin eight threads at once. To spin on this machine required a great deal of skill. A length of roving was passed through the clamp or clove. The left hand was used to close this and draw the roving away from the spindles which were rotated by the spinner turning the horizontal wheel with the right hand. The spindles twisted the fibres as they were being drawn out. At the end of the draw, the spindles continued to be rotated until sufficient twist had been put into the fibres to make the finished yarn. This was backed off from the tips of the spindles by reversing them and then, with the spindles turning in the spinning direction once more, the yarn was wound on by the right hand rotating the spindles, the left hand pushing the clove back towards them and one foot operating a pedal which guided the yarn onto the spindles by a faller wire. A piecer was needed to rejoin the yarns when they broke. At first Hargreaves's jenny was worked only by his family, but then he sold two or three of them, possibly to Peel. In 1768, local opposition and a riot in which his house was gutted forced him to flee to Nottingham. He entered into partnership there with Thomas James and established a cotton mill. In 1770 he followed Arkwright's example and sought to patent his machine and brought an action for infringement against some Lancashire manufacturers, who offered £3,000 in settlement. Hargreaves held out for £4,000, but he was unable to enforce his patent because he had sold jennies before leaving Lancashire. Arkwright's "water twist" was more suitable for the Nottingham hosiery industry trade than jenny yarn and in 1777 Hargreaves replaced his own machines with Arkwright's. When he died the following year, he is said to have left property valued at £7,000 and his widow received £400 for her share in the business. Once the jenny had been made public, it was quickly improved by other inventors and the number of spindles per machine increased. In 1784, there were reputed to be 20,000 jennies of 80 spindles each at work. The jenny greatly eased the shortage of cotton weft for weavers.

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SUBJECT AREA: Horology

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Huygens was born into a cultured and privileged class. His father, Constantijn, was a poet and statesman who had wide interests. Constantijn exerted a strong influence on his son, who was educated at home until he reached the age of 16. Christiaan studied law and mathematics at Ley den University from 1645 to 1647, and continued his studies at the Collegium Arausiacum in Breda until 1649. He then lived at The Hague, where he had the means to devote his time entirely to study. In 1666 he became a Member of the Académie des Sciences in Paris and settled there until his return to The Hague in 1681. He also had a close relationship with the Royal Society and visited London on three occasions, meeting Newton on his last visit in 1689. Huygens had a wide range of interests and made significant contributions in mathematics, astronomy, optics and mechanics. He also made technical advances in optical instruments and horology.

Despite the efforts of Burgi there had been no significant improvement in the performance of ordinary clocks and watches from their inception to Huygens's time, as they were controlled by foliots or balances which had no natural period of oscillation. The pendulum appeared to offer a means of improvement as it had a natural period of oscillation that was almost independent of amplitude. Galileo Galilei had already pioneered the use of a freely suspended pendulum for timing events, but it was by no means obvious how it could be kept swinging and used to control a clock. Towards the end of his life Galileo described such a. mechanism to his son Vincenzio, who constructed a model after his father's death, although it was not completed when he himself died in 1642. This model appears to have been copied in Italy, but it had little influence on horology, partly because of the circumstances in which it was produced and possibly also because it differed radically from clocks of that period. The crucial event occurred on Christmas Day 1656 when Huygens, quite independently, succeeded in adapting an existing spring-driven table clock so that it was not only controlled by a pendulum but also kept it swinging. In the following year he was granted a privilege or patent for this clock, and several were made by the clockmaker Salomon Coster of The Hague. The use of the pendulum produced a dramatic improvement in timekeeping, reducing the daily error from minutes to seconds, but Huygens was aware that the pendulum was not truly isochronous. This error was magnified by the use of the existing verge escapement, which made the pendulum swing through a large arc. He overcame this defect very elegantly by fitting cheeks at the pendulum suspension point, progressively reducing the effective length of the pendulum as the amplitude increased. Initially the cheeks were shaped empirically, but he was later able to show that they should have a cycloidal shape. The cheeks were not adopted universally because they introduced other defects, and the problem was eventually solved more prosaically by way of new escapements which reduced the swing of the pendulum. Huygens's clocks had another innovatory feature: maintaining power, which kept the clock going while it was being wound.

Pendulums could not be used for portable timepieces, which continued to use balances despite their deficiencies. Robert Hooke was probably the first to apply a spring to the balance, but his efforts were not successful. From his work on the pendulum Huygens was well aware of the conditions necessary for isochronism in a vibrating system, and in January 1675, with a flash of inspiration, he realized that this could be achieved by controlling the oscillations of the balance with a spiral spring, an arrangement that is still used in mechanical watches. The first model was made for Huygens in Paris by the clockmaker Isaac Thuret, who attempted to appropriate the invention and patent it himself. Huygens had for many years been trying unsuccessfully to adapt the pendulum clock for use at sea (in order to determine longitude), and he hoped that a balance-spring timekeeper might be better suited for this purpose. However, he was disillusioned as its timekeeping proved to be much more susceptible to changes in temperature than that of the pendulum clock.

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SUBJECT AREA: Aerospace, Architecture and building, Horology, Weapons and armour

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Leonardo was the illegitimate son of a Florentine lawyer. His first sixteen years were spent with the lawyer's family in the rural surroundings of Vinci, which aroused in him a lifelong love of nature and an insatiable curiosity in it. He received little formal education but extended his knowledge through private reading. That gave him only a smattering of Latin, a deficiency that was to be a hindrance throughout his active life. At sixteen he was apprenticed in the studio of Andrea del Verrochio in Florence, where he received a training not only in art but in a wide variety of crafts and technical arts.

In 1482 Leonardo went to Milan, where he sought and obtained employment with Ludovico Sforza, later Duke of Milan, partly to sculpt a massive equestrian statue of Ludovico but the work never progressed beyond the full-scale model stage. He did, however, complete the painting which became known as the Virgin of the Rocks and in 1497 his greatest artistic achievement, The Last Supper, commissioned jointly by Ludovico and the friars of Santa Maria della Grazie and painted on the wall of the monastery's refectory. Leonardo was responsible for the court pageants and also devised a system of irrigation to supply water to the plains of Lombardy. In 1499 the French army entered Milan and deposed Leonardo's employer. Leonardo departed and, after a brief visit to Mantua, returned to Florence, where for a time he was employed as architect and engineer to Cesare Borgia, Duke of Romagna. Around 1504 he completed another celebrated work, the Mona Lisa.

In 1506 Leonardo began his second sojourn in Milan, this time in the service of King Louis XII of France, who appointed him "painter and engineer". In 1513 Leonardo left for Rome in the company of his pupil Francesco Melzi, but his time there was unproductive and he found himself out of touch with the younger artists active there, Michelangelo above all. In 1516 he accepted with relief an invitation from King François I of France to reside at the small château of St Cloux in the royal domain of Amboise. With the pension granted by François, Leonardo lived out his remaining years in tranquility at St Cloux.

Leonardo's career can hardly be regarded as a success or worthy of such a towering genius. For centuries he was known only for the handful of artistic works that he managed to complete and have survived more or less intact. His main activity remained hidden until the nineteenth and twentieth centuries, during which the contents of his notebooks were gradually revealed. It became evident that Leonardo was one of the greatest scientific investigators and inventors in the history of civilization. Throughout his working life he extended a searching curiosity over an extraordinarily wide range of subjects. The notes show careful investigation of questions of mechanical and civil engineering, such as power transmission by means of pulleys and also a form of chain belting. The notebooks record many devices, such as machines for grinding and polishing lenses, a lathe operated by treadle-crank, a rolling mill with conical rollers and a spinning machine with pinion and yard divider. Leonardo made an exhaustive study of the flight of birds, with a view to designing a flying machine, which obsessed him for many years.

Leonardo recorded his observations and conclusions, together with many ingenious inventions, on thousands of pages of manuscript notes, sketches and drawings. There are occasional indications that he had in mind the publication of portions of the notes in a coherent form, but he never diverted his energy into putting them in order; instead, he went on making notes. As a result, Leonardo's impact on the development of science and technology was virtually nil. Even if his notebooks had been copied and circulated, there were daunting impediments to their understanding. Leonardo was left-handed and wrote in mirror-writing: that is, in reverse from right to left. He also used his own abbreviations and no punctuation.

At his death Leonardo bequeathed his entire output of notes to his friend and companion Francesco Melzi, who kept them safe until his own death in 1570. Melzi left the collection in turn to his son Orazio, whose lack of interest in the arts and sciences resulted in a sad period of dispersal which endangered their survival, but in 1636 the bulk of them, in thirteen volumes, were assembled and donated to the Ambrosian Library in Milan. These include a large volume of notes and drawings compiled from the various portions of the notebooks and is now known as the Codex Atlanticus. There they stayed, forgotten and ignored, until 1796, when Napoleon's marauding army overran Italy and art and literary works, including the thirteen volumes of Leonardo's notebooks, were pillaged and taken to Paris. After the war in 1815, the French government agreed to return them but only the Codex Atlanticus found its way back to Milan; the rest remained in Paris. The appendix to one notebook, dealing with the flight of birds, was later regarded as of sufficient importance to stand on its own. Four small collections reached Britain at various times during the seventeenth and eighteenth centuries; of these, the volume in the Royal Collection at Windsor Castle is notable for its magnificent series of anatomical drawings. Other collections include the Codex Leicester and Codex Arundel in the British Museum in London, and the Madrid Codices in Spain.

Towards the end of the nineteenth century, Leonardo's true stature as scientist, engineer and inventor began to emerge, particularly with the publication of transcriptions and translations of his notebooks. The volumes in Paris appeared in 1881–97 and the Codex Atlanticus was published in Milan between 1894 and 1904.

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SUBJECT AREA: Photography, film and optics

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The son of a Wesleyan minister, Mees was interested in chemistry from an early age and studied at St Dunstan's College in Catford, where he met Samuel E.Sheppard, with whom he went on to University College London in 1900. They worked together on a thesis for BSc degrees in 1903, developing the work begun by Hurter and Driffield on photographic sensitometry. This and other research papers were published in 1907 in the book Investigations on the Theory of the Photographic Process, which became a standard reference work. After obtaining a doctorate in 1906, Mees joined the firm of Wratten \& Wainwright (see F.C.L.Wratten), manufacturers of dry plates in Croydon; he started work on 1 April 1906, first tackling the problem of manufacturing colour-sensitive emulsions and enabling the company to market the first fully panchromatic plates from the end of that year.

During the next few years Mees ran the commercial operation of the company as Managing Director and carried out research into new products, including filters for use with the new emulsions. In January 1912 he was visited by George Eastman, the American photographic manufacturer, who asked him to go to Rochester, New York, and set up a photographic research laboratory in the Kodak factory there. Wratten was prepared to release Mees on condition that Eastman bought the company; thus, Wratten and Wainwright became part of Kodak Ltd, and Mees left for America. He supervised the construction of a building in the heart of Kodak Park, and the building was fully equipped not only as a research laboratory, but also with facilities for coating and packing sensitized materials. It also had the most comprehensive library of photographic books in the world. Work at the laboratory started at the beginning of 1913, with a staff of twenty recruited from America and England, including Mees's collaborator of earlier years, Sheppard. Under Mees's direction there flowed from the Kodak research Laboratory a constant stream of discoveries, many of them leading to new products. Among these were the 16 mm amateur film-making system launched in 1923; the first amateur colour-movie system, Kodacolor, in 1928; and 8 mm home movies, in 1932. His support for the young experimenters Mannes and Godowsky, who were working on colour photography, led to their joining the Research Laboratory and to the introduction of the first multi-layer colour film, Kodachrome, in 1935. Eastman had agreed from the beginning that as much of the laboratory's work as possible should be published, and Mees himself wrote prolifically, publishing over 200 articles and ten books. While he made significant contributions to the understanding of the photographic process, particularly through his early research, it is his creation and organization of the Kodak Research Laboratory that is his lasting memorial. His interests were many and varied, including Egyptology, astronomy, marine biology and history. He was a Fellow of the Royal Society.

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SUBJECT AREA: Agricultural and food technology

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The son of the millwright James Meikle, who is credited with the introduction of the winnowing machine into Britain, Andrew Meikle followed in his father's footsteps. His inventive inclinations were first turned to developing his father's idea, and together with his own son George he built and patented a double-fan winnowing machine.

However, in the history of agricultural development Andrew Meikle is most famous for his invention of the threshing machine, patented in 1784. He had been presented with a model of a threshing mill designed by a Mr Ilderton of Northumberland, but after failing to make a full-scale machine work, he developed the concept further. He eventually built the first working threshing machine for a farmer called Stein at Kilbagio. The patent revolutionized farming practice because it displaced the back-breaking and soul-destroying labour of flailing the grain from the straw. The invention was of great value in Scotland and in northern England when the land was becoming underpopulated as a result of heavy industrialization, but it was bitterly opposed in the south of England until well into the nineteenth century. Although the introduction of the threshing machine led to the "Captain Swing" riots of the 1830s, in opposition to it, it shortly became universal.

Meikle's provisional patent in 1785 was a natural progression of earlier attempts by other millwrights to produce such a machine. The published patent is based on power provided by a horse engine, but these threshing machines were often driven by water-wheels or even by windmills. The corn stalks were introduced into the machine where they were fed between cast-iron rollers moving quite fast against each other to beat the grain out of the ears. The power source, whether animal, water or wind, had to cause the rollers to rotate at high speed to knock the grain out of the ears. While Meikle's machine was at first designed as a fixed barn machine powered by a water-wheel or by a horse wheel, later threshing machines became mobile and were part of the rig of an agricultural contractor.

In 1788 Meikle was awarded a patent for the invention of shuttered sails for windmills. This patent is part of the general description of the threshing machine, and whilst it was a practical application, it was superseded by the work of Thomas Cubitt.

At the turn of the century Meikle became a manufacturer of threshing machines, building appliances that combined the threshing and winnowing principles as well as the reciprocating "straw walkers" found in subsequent threshing machines and in conventional combine harvesters to the present day. However, he made little financial gain from his invention, and a public subscription organized by the President of the Board of Agriculture, Sir John Sinclair, raised £1,500 to support him towards the end of his life.

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SUBJECT AREA: Broadcasting, Electronics and information technology, Telecommunications

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As a Jewish boy in Russia, Sarnoff spent several years preparing to be a Talmudic Scholar, but in 1900 the family emigrated to the USA and settled in Albany, New York. While at public school and at the Pratt Institute in Brooklyn, New York, he helped the family finances by running errands, selling newspapers and singing the liturgy in the synagogue. After a short period as a messenger boy with the Commercial Cable Company, in 1906 he became an office boy with the Marconi Wireless Telegraph Company of America (see G. Marconi). Having bought a telegraph instrument with his first earnings, he taught himself Morse code and was made a junior telegraph operator in 1907. The following year he became a wireless operator at Nantucket Island, then in 1909 he became Manager of the Marconi station at Sea Gate, New York. After two years at sea he returned to a shore job as wireless operator at the world's most powerful station at Wanamaker's store in Manhattan. There, on 14 April 1912, he picked up the distress signals from the sinking iner Titanic, remaining at his post for three days.

Rewarded by rapid promotion (Chief Radio Inspector 1913, Contract Manager 1914, Assistant Traffic Manager 1915, Commercial Manager 1917) he proposed the introduction of commercial radio broadcasting, but this received little response. Consequently, in 1919 he took the job of Commercial Manager of the newly formed Radio Corporation of America (RCA), becoming General Manager in 1921, Vice- President in 1922, Executive Vice-President in 1929 and President in 1930. In 1921 he was responsible for the broadcasting of the Dempsey-Carpentier title-fight, as a result of which RCA sold $80 million worth of radio receivers in the following three years. In 1926 he formed the National Broadcasting Company (NBC). Rightly anticipating the development of television, in 1928 he inaugurated an experimental NBC television station and in 1939 demonstrated television at the New York World Fair. Because of his involvement with the provision of radio equipment for the armed services, he was made a lieutenant-colonel in the US Signal Corps Reserves in 1924, a full colonel in 1931 and, while serving as a communications consultant to General Eisenhower during the Second World War, Brigadier General in 1944.

With the end of the war, RCA became a major manufacturer of television receivers and then invested greatly in the ultimately successful development of shadowmask tubes and receivers for colour television. Chairman and Chief Executive from 1934, Sarnoff held the former post until his retirement in 1970.

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discount.

hacer descuento to give a discount

con descuento at a discount

un descuento del 10 por ciento 10 percent off

1^st person singular (yo) present indicative of spanish verb: descontar.

* * *

► nombre masculino

1 discount, reduction, deduction

2 DEPORTE injury time

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con descuento at a discount, on offer

■ el precio con descuento es de siete euros the discount price is seven euros

descuento por pronto pago cash discount

* * *

* * *

1) (Com) discount

2) (Dep) injury time, overtime (EEUU)

* * *

1)

a) ( rebaja) discount

b) ( del sueldo) deduction

2) (Dep) injury time

3) (de letra, pagaré) discount

* * *

1)

a) ( rebaja) discount

b) ( del sueldo) deduction

2) (Dep) injury time

3) (de letra, pagaré) discount

* * *

descuento¹

¹ = discount, deduction, rebate, trade-in allowance, discount ticket, reduced rate, special rate, reduced fee, discounted price, discount price, marked-down price, mark-down.

Nota: Generalmente referido a los precios.

descuento²

² = injury time.

* * *

1 (rebaja) discount

[ S ] no se hacen descuentos no discounts given

me hicieron un descuento del 15% I got a 15% discount

compre Cremol, ahora con descuento buy Cremol, now on special offer

descuentos para empleados staff discounts

2 (del sueldo) deduction

B ( Dep) injury time

marcó en el (tiempo de) descuento he scored in injury time

estar jugando los descuentos (CS fam); to be on one's last legs ( colloq), to have one foot in the grave ( colloq)

C (de una letra, un pagaré) discount

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1ª persona singular (yo) presente indicativo

a) ( rebajar):

◊ me descontó el 15% he gave me a 15% discount

b) ( restar) ‹gastos/impuestos› to deduct, take off;

◊ si descontamos a Pedro/los domingos … if we don't count Pedro/Sundays …

a) ( rebaja) discount;

◊ hacen un descuento del 15% they give a 15% discount

b) ( del sueldo) deduction

* * *

♦ ver descontar

♦ nm

1. [rebaja] discount;

un descuento del 5 por ciento 5 percent off;

con descuento at a discount;

vendemos todo con descuento we sell everything at a discount;

artículos con descuento discounted items;

con el descuento se le queda en 5.000 with the discount it comes to 5,000;

hacer descuento to give a discount;

nos hicieron un descuento del 10 por ciento they gave us a 10 percent discount;

llevar descuento to be on special offer;

los trajes no llevan descuento there are no discounts on suits

descuento duro hard discount

2. [en fútbol]

marcaron en el tiempo de descuento they scored in injury time

3. [de remuneración, salario] deduction

4. Fin [de letra de cambio] discount

* * *

1 discount

2 DEP stoppage time

* * *

descuento nm

rebaja: discount

* * *

descuento n

1. (rebaja) discount / reduction

2. (tiempo añadido) injury time

(1949-)

   Political leader and administrator, law professor, editor, and writer. A son of Baltazar Rebelo de Sousa, important administrator, governor-general of Mozambique, and cabinet minister during the Estado Novo, Rebelo de Sousa took a law degree at the University of Lisbon Law Faculty. Near the end of the Estado Novo, he was a founding editor of the influential, independent weekly paper Expresso, and years later became director or chief editor. As a member of the Social Democratic Party (PSD) after the Revolution of 25 April 1974, Rebelo de Sousa held a variety of positions from deputy to the Constituent Assembly, which wrote the 1976 Constitution, to ministerial posts. He moved up in the PSD after the retirement of Aníbal Cavaco Silva in 1995 to become leader of that party, the most important political grouping next to the Socialist Party (PS). Marcelo Rebelo de Sousa was an unsuccessful candidate for prime minister in the 1999 elections for the Assembly of the Republic. A noted legal authority and a law academic who publishes frequently, he remained a professor of law at University of Lisbon's Law Faculty and the Catholic University, and was the author of law texts. He has also held various municipal posts from Cascais to Celorico de Basto.

until

❢ When used as a preposition in positive sentences until is translated by jusqu'à: they're staying until Monday = ils restent jusqu'à lundi. Remember that jusqu'à + le becomes jusqu'au and jusqu'à + les becomes jusqu'aux: until the right moment = jusqu'au bon moment ; until the exams = jusqu'aux examens. In negative sentences not until is translated by ne…pas avant: I can't see you until Friday = je ne peux pas vous voir avant vendredi. When used as a conjunction in positive sentences until is translated by jusqu'à ce que + subjunctive: we'll stay here until Maya comes back = nous resterons ici jusqu'à ce que Maya revienne. In negative sentences where the two verbs have different subjects not until is translated by ne…pas avant que + subjunctive: we won't leave until Maya comes back = nous ne partirons pas avant que Maya revienne. In negative sentences where the two verbs have the same subject not until is translated by pas avant de + infinitive: we won't leave until we've seen Claire = nous ne partirons pas avant d'avoir vu Claire. For more examples and particular usages see the entry until.

A prep

1 ( also till) ( up to a specific time) jusqu'à ; ( after negative verb) avant ; until Tuesday jusqu'à mardi ; until the sixties jusqu'aux années soixante ; until very recently il n'y a encore pas si longtemps ; until a year ago jusqu'à il y a un an ; until now jusqu'à présent ; until then jusqu'à ce moment-là, jusque-là ; (up) until 1901 jusqu'en or jusqu'à 1901 ; valid (up) until April 1993 valable jusqu' en avril 1993 ; you have until the end of the month vous avez jusqu'à la fin du mois (to do pour faire) ; until the day he died jusqu'à sa mort ; until well after midnight bien au-delà de minuit ; to wait until after Easter attendre après Pâques ; from Monday until Saturday du lundi au samedi ; put it off until tomorrow remets-le à demain ; until such time as you find work jusqu'à ce que tu trouves ( subj) du travail, en attendant que tu trouves ( subj) du travail ; it won't be ready until next week ça ne sera pas prêt avant la semaine prochaine ; I won't know until Tuesday je n'aurai pas la réponse avant mardi ; they didn't ring until the following day ils n'ont pas appelé avant le lendemain ; it wasn't until the 50's that… ce n'est qu'à partir des années cinquante que… ; nothing changed until after the war ce n'est qu'après la guerre que les choses ont commencé à changer ;

2 ( as far as) jusqu'à ; stay on the bus until Egham ne descends pas du bus avant Egham.

B conj ( also till) ( with past and present tenses) jusqu'à ce que (+ subj) ; ( in negative constructions) avant que (+ subj), avant de (+ infinitive) ; we'll stay until a solution is reached nous resterons jusqu'à ce que nous trouvions une solution ; and so it continued until they left et cela a continué jusqu'à ce qu'ils partent or jusqu'à leur départ ; let's watch TV until they arrive regardons la télévision en attendant qu'ils arrivent ( subj) ; things won't improve until we have democracy la situation ne s'améliorera pas tant que nous ne serons pas en démocratie ; stir mixture until (it is) smooth Culin mélangez bien jusqu'à obtenir une pâte lisse ; until you are dead Jur jusqu'à ce que mort s'ensuive ; wait until I get back attends que je rentre ( subj) ; I'll wait until I get back j'attendrai d'être rentré (before doing pour faire) ; wait until I tell you! attends! il faut que je te raconte! ; she waited until she was alone/they were alone elle a attendu d'être seule/qu'ils soient seuls ; don't look until I tell you to ne regarde pas avant que je te le dise ; you can't leave until you've completed the course tu ne peux pas partir avant d'avoir fini le stage ; don't ring me until you know for sure ne m'appelle pas avant d'être sûr ; we can't decide until we know the details nous ne pouvons pas prendre de décision tant que nous n'avons pas de précisions ; not until then did she realize that ce n'est qu'à ce moment-là qu'elle s'est rendu compte que ; ⇒ death.

SUBJECT AREA: Textiles

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Bigelow was born in West Boyleston, Massachusetts, where his father struggled as a farmer, wheelwright, and chairmaker. Before he was 20, Bigelow had many different jobs, among them farm labourer, clerk, violin player and cotton-mill employee. In 1830, he went to Leicester Academy, Massachusetts, but he could not afford to go on to Harvard. He sought work in Boston, New York and elsewhere, making various inventions.

The most important of his early inventions was the power loom of 1837 for making coach lace. This loom contained all the essential features of his carpet looms, which he developed and patented two years later. He formed the Clinton Company for manufacturing carpets at Leicester, Massachusetts, but the factory became so large that its name was adopted for the town. The next twenty years saw various mechanical discoveries, while his range of looms was extended to cover Brussels, Wilton, tapestry and velvet carpets. Bigelow has been justly described as the originator of every fundamental device in these machines, which were amongst the largest textile machines of their time. The automatic insertion and withdrawal of strong wires with looped ends was the means employed to raise the looped pile of the Brussels carpets, while thinner wires with a knife blade at the end raised and then severed the loops to create the rich Wilton pile. At the Great Exhibition in 1851, it was declared that his looms made better carpets than any from hand looms. He also developed other looms for special materials.

He became a noted American economist, writing two books about tariff problems, advocating that the United States should not abandon its protectionist policies. In 1860 he was narrowly defeated in a Congress election. The following year he was a member of the committee that established the Massachusetts Institute of Technology.

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SUBJECT AREA: Chemical technology

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Bosch spent a year as a metalworker before studying chemistry at Leipzig University, obtaining his doctorate in 1898. The following year, he entered Badische Soda-, Anilin Fabrik (BASF), the leading German manufacturer of dyestuflfs. Between 1902 and 1907 he spent much time investigating processes for nitrogen fixation. In 1908 Fritz Haber told BASF of his laboratory-scale synthesis of ammonia from its constituent elements, and in the following year Bosch was assigned to developing it to the industrial scale. Leading a large team of chemists and engineers, Bosch designed the massive pressure converter and other features of the process and was the first to use the water gas shift reaction to produce the large quantities of hydrogen that were required. By 1913 Bosch had completed the largest chemical engineering plant at BASF's works at Oppau, and soon it was producing 36,000 tons of ammonium sulphate a year. Bosch enlarged the Oppau plant and went on to construct a larger plant at Leuna.

In 1914 Bosch was appointed a Director of BASF. At the end of the First World War he became Technical Adviser to the German delegation at the peace conference. During the 1920s BASF returned to its position of pre-eminence in high-pressure technology, thanks largely to Bosch's leadership. Although increasingly absorbed in administrative matters, Bosch was able to support the synthesis of methane and the hydrogenation of coal tar and lignite to make petrol. In 1925 BASF merged with other companies to form the giant IG Farbenindustrie AG, of which Bosch became Chairman of the Managing Board. His achievements received international recognition in 1931 when he was awarded, with F. Bergius, the Nobel Prize in Chemistry for high-pressure synthesis.

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SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering

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Although known as Clement in his professional life, his baptism at Asby and his death were registered under the name of Joseph Clemmet. He worked as a slater until the age of 23, but his interest in mechanics led him to spend much of his spare time in the local blacksmith's shop. By studying books on mechanics borrowed from his cousin, a watchmaker, he taught himself and with the aid of the village blacksmith made his own lathe. By 1805 he was able to give up the slating trade and find employment as a mechanic in a small factory at Kirkby Stephen. From there he moved to Carlisle for two years, and then to Glasgow where, while working as a turner, he took lessons in drawing; he had a natural talent and soon became an expert draughtsman. From about 1809 he was employed by Leys, Mason \& Co. of Aberdeen designing and making power looms. For this work he built a screw-cutting lathe and continued his self-education. At the end of 1813, having saved about £100, he made his way to London, where he soon found employment as a mechanic and draughtsman. Within a few months he was engaged by Joseph Bramah, and after a trial period a formal agreement dated 1 April 1814 was made by which Clement was to be Chief Draughtsman and Superintendent of Bramah's Pimlico works for five years. However, Bramah died in December 1814 and after his sons took over the business it was agreed that Clement should leave before the expiry of the five-year period. He soon found employment as Chief Draughtsman with Henry Maudslay \& Co. By 1817 Clement had saved about £500, which enabled him to establish his own business at Prospect Place, Newington Butts, as a mechanical draughtsman and manufacturer of high-class machinery. For this purpose he built lathes for his own use and invented various improvements in their detailed design. In 1827 he designed and built a facing lathe which incorporated an ingenious system of infinitely variable belt gearing. He had also built his own planing machine by 1820 and another, much larger one in 1825. In 1828 Clement began making fluted taps and dies and standardized the screw threads, thus anticipating on a small scale the national standards later established by Sir Joseph Whitworth. Because of his reputation for first-class workmanship, Clement was in the 1820s engaged by Charles Babbage to carry out the construction of his first Difference Engine.

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SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering, Weapons and armour

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Frederick W.Howe attended local schools until the age of 16 and then entered the machine shop of Gay \& Silver at North Chelmsford, Massachusetts, as an apprentice and remained with that firm for nine years. He then joined Robbins, Kendall \& Lawrence of Windsor, Vermont, as Assistant to Richard S. Lawrence in designing machine tools. A year later (1848) he was made Plant Superintendent. During his time with this firm, Howe designed a profiling machine which was used in all gun shops in the United States: a barrel-drilling and rifling machine, and the first commercially successful milling machine. Robbins \& Lawrence took to the Great Exhibition of 1851 in London, England, a set of rifles built on the interchangeable system. The interest this created resulted in a visit of some members of the British Royal Small Arms Commission to America and subsequently in an order for 150 machine tools, jigs and fixtures from Robbins \& Lawrence, to be installed at the small-arms factory at Enfield. From 1853 to 1856 Howe was in charge of the design and building of these machines. In 1856 he established his own armoury at Newark, New Jersey, but transferred after two years to Middletown, Connecticut, where he continued the manufacture of small arms until the outbreak of the Civil War. He then became Superintendent of the armoury of the Providence Tool Company at Providence, Rhode Island, and served in that capacity until the end of the war. In 1865 he went to Bridgeport, Connecticut, to assist Elias Howe with the manufacture of his sewing machine. After the death of Elias Howe, Frederick Howe returned to Providence to join the Brown \& Sharpe Manufacturing Company. As Superintendent of that establishment he worked with Joseph R. Brown in the development of many of the firm's products, including machinery for the Wilcox \& Gibbs sewing machine then being made by Brown \& Sharpe. From 1876 Howe was in business on his own account as a consulting mechanical engineer and in his later years he was engaged in the development of shoe machinery and in designing a one-finger typewriter, which, however, was never completed. He was granted several patents, mainly in the fields of machine tools and firearms. As a designer, Howe was said to have been a perfectionist, making frequent improvements; when completed, his designs were always sound.

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SUBJECT AREA: Electricity, Public utilities

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Jablochkoff studied at the Military Engineering College in St Petersburg. Having a scientific bent, he was sent to the Military Galvano Technical School. At the end of his military service in 1871 he was appointed Director General of the Moscow-Kursk telegraph lines for the Midi Railway Company. At this time he began to develop an interest in electric lighting, and in 1875 he left the Imperial Telegraph Service to devote his time exclusively to scientific pursuits. He found employment at the workshop of M Bréguet in Paris, where Gramme dynamos and Serrin arc lamps were being constructed. After some experimentation he found a means of producing a carbon arc that regulated itself without any mechanism. This lamp, the Jablochkoff candle, with two carbon rods placed parallel to each other and so close that an arc formed at the ends, could continue to burn until the rods were consumed. Plaster of Paris was used to separate the two electrodes and crumbled away as the carbon burned, thus exposing fresh carbon. These lamps were used in May 1878 in Paris to illuminate the avenue de l'Opéra, and later in Rome and London, and in essence were the first practical electric street lighting. Since there was no regulating mechanism, several candles could be placed in a single circuit. Despite inherent defects, such as the inability to restart the lamps after they were extinguished by wind or interruption of supply, they remained in use for some purposes for several years on account of their simplicity and cheapness. In 1877 Jablochkoff obtained the earliest patent to employ transformers to distribute current in an alternating-current circuit.

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SUBJECT AREA: Aerospace

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Charles Renard was a French army officer with an interest in aviation. In 1873 he constructed an unusual unmanned glider with ten wings and an automatic stabilizing device to control rolling. This operated by means of a pendulum device linked to moving control surfaces. The model was launched from a tower near Arras, but unfortunately it spiralled into the ground. The control surfaces could not cope with the basic instability of the design, but as an idea for automatic flight control it was ahead of its time.

Following a Commission report on the military use of balloons, carrier pigeons and an optical telegraph, an aeronautical establishment was set up in 1877 at Chalais-Meudon, near Paris, under the direction of Charles Renard, who was assisted by his brother Paul. The following year Renard and a colleague, Arthur Krebs, began to plan an airship. They received financial help from Léon Gambetta, a prominent politician who had escaped from Paris by balloon in 1870 during the siege by the Prussians. Renard and Krebs studied earlier airship designs: they used the outside shape of Paul Haenlein's gas-engined airship of 1872 and included Meusnier's internal air-filled ballonnets. The gas-engine had not been a success so they decided on an electric motor. Renard developed lightweight pile batteries while Krebs designed a motor, although this was later replaced by a more powerful Gramme motor of 6.5 kW (9 hp). La France was constructed at Chalais-Meudon and, after a two-month wait for calm conditions, the airship finally ascended on 9 August 1884. The motor was switched on and the flight began. Renard and Krebs found their airship handled well and after twenty-three minutes they landed back at their base. La, France made several successful flights, but its speed of only 24 km/h (15 mph) meant that flights could be made only in calm weather. Parts of La, France, including the electric motor, are preserved in the Musée de l'Air in Paris.

Renard remained in charge of the establishment at Chalais-Meudon until his death. Among other things, he developed the "Train Renard", a train of articulated road vehicles for military and civil use, of which a number were built between 1903 and 1911. Towards the end of his life Renard became interested in helicopters, and in 1904 he built a large twin-rotor model which, however, failed to take off.

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SUBJECT AREA: Electronics and information technology

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Stibitz spent his early years in Dayton, Ohio, and obtained his first degree at Denison University, Granville, Ohio, his MS from Union College, Schenectady, New York, in 1927 and his PhD in mathematical physics from Cornell University, Ithaca, New York, in 1930. After working for a time for General Electric, he joined Bell Laboratories to work on various communications problems. In 1937 he started to experiment at home with telephone relays as the basis of a calculator for addition, multiplication and division. Initially this was based on binary arithmetic, but later he used binary-coded decimal (BCD) and was able to cope with complex numbers. In November 1938 the ideas were officially taken up by Bell Laboratories and, with S.B.Williams as Project Manager, Stibitz built a complex-number computer known as "Complex", or Relay I, which became operational on 8 January 1940.

With the outbreak of the Second World War, he was co-opted to the National Defence Research Council to work on anti-aircraft (AA) gun control, and this led to Bell Laboratories Relay II computer, which was completed in 1943 and which had 500 relays, bi-quinary code and selfchecking of errors. A further computer, Relay III, was used for ballistic simulation of actual AA shell explosions and was followed by more machines before and after Stibitz left Bell after the end of the war. Stibitz then became a computer consultant, involved in particular with the development of the UNIVAC computer by John Mauchly and J.Presper Eckert.

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