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  • 41 Black, Harold Stephen

    [br]
    b. 14 April 1898 Leominster, Massachusetts, USA
    d. 11 December 1983 Summitt, New Jersey, USA
    [br]
    American electrical engineer who discovered that the application of negative feedback to amplifiers improved their stability and reduced distortion.
    [br]
    Black graduated from Worcester Polytechnic Institute, Massachusetts, in 1921 and joined the Western Electric Company laboratories (later the Bell Telephone Laboratories) in New York City. There he worked on a variety of electronic-communication problems. His major contribution was the discovery in 1927 that the application of negative feedback to an amplifier, whereby a fraction of the output signal is fed back to the input in the opposite phase, not only increases the stability of the amplifier but also has the effect of reducing the magnitude of any distortion introduced by it. This discovery has found wide application in the design of audio hi-fi amplifiers and various control systems, and has also given valuable insight into the way in which many animal control functions operate.
    During the Second World War he developed a form of pulse code modulation (PCM) to provide a practicable, secure telephony system for the US Army Signal Corps. From 1963–6, after his retirement from the Bell Labs, he was Principal Research Scientist with General Precision Inc., Little Falls, New Jersey, following which he became an independent consultant in communications. At the time of his death he held over 300 patents.
    [br]
    Principal Honours and Distinctions
    Institute of Electronic and Radio Engineers Lamme Medal 1957.
    Bibliography
    1934, "Stabilised feedback amplifiers", Electrical Engineering 53:114 (describes the principles of negative feedback).
    21 December 1937, US patent no. 2,106,671 (for his negative feedback discovery.
    1947, with J.O.Edson, "Pulse code modulation", Transactions of the American Institute of Electrical Engineers 66:895.
    1946, "A multichannel microwave radio relay system", Transactions of the American Institute of Electrical Engineers 65:798.
    1953, Modulation Theory, New York: D.van Nostrand.
    1988, Laboratory Management: Principles \& Practice, New York: Van Nostrand Rheinhold.
    Further Reading
    For early biographical details see "Harold S. Black, 1957 Lamme Medalist", Electrical Engineering (1958) 77:720; "H.S.Black", Institute of Electrical and Electronics Engineers Spectrum (1977) 54.
    KF

    Biographical history of technology > Black, Harold Stephen

  • 42 Boot, Henry Albert Howard

    [br]
    b. 29 July 1917 Birmingham, England
    d. 8 February 1983 Cambridge, England
    [br]
    English physicist who, with John Randall, invented the cavity magnetron used in radar systems.
    [br]
    After secondary education at King Edward School, Birmingham, Boot studied physics at Birmingham University, obtaining his BSc in 1938 and PhD in 1941. With the outbreak of the Second World War, he became involved with Randall and others in the development of a source of microwave power suitable for use in radar transmitters. Following unsuccessful attempts to use klystrons, they turned to investigation of the magnetron, and by adding cavity resonators they obtained useful power on 21 February 1940 at a wavelength of 9.8 cm. By May a cavity magnetron radar system had been constructed at TRE, Swanage, and in September submarine periscopes were detected at a range of 7 miles (11 km).
    In 1943 the physics department at Birmingham resumed its research in atomic physics and Boot moved to BTH at Rugby to continue development of magnetrons, but in 1945 he returned to Birmingham as Nuffield Research Fellow and helped construct the cyclotron there. Three years later he took up a post as a Principal Scientific Officer (PSO) at the Services Electronic Research Laboratories at Baldock, Hertfordshire, becoming a Senior PSO in 1954. He remained there until his retirement in 1977, variously carrying out research on microwaves, magnetrons, plasma physics and lasers.
    [br]
    Principal Honours and Distinctions
    Royal Society of Arts Thomas Gray Memorial Prize 1943. Royal Commission Inventors Award 1946. Franklin Institute John Price Wetherill Medal 1958. City of Pennsylvania John Scott Award 1959. (All jointly with Randall.)
    Bibliography
    1976, with J.T.Randall, "Historical notes on the cavity magnetron", Transactions of the Institute of Electrical and Electronics Engineers ED-23: 724 (provides an account of their development of the cavity magnetron).
    Further Reading
    E.H.Dix and W.H.Aldous, 1966, Microwave Valves.
    KF

    Biographical history of technology > Boot, Henry Albert Howard

  • 43 Clerk, Sir Dugald

    [br]
    b. 31 March 1854 Glasgow, Scotland
    d. 12 November 1932 Ewhurst, Surrey, England
    [br]
    Scottish mechanical engineer, inventor of the two-stroke internal combustion engine.
    [br]
    Clerk began his engineering training at about the age of 15 in the drawing office of H.O.Robinson \& Company, Glasgow, and in his father's works. Meanwhile, he studied at the West of Scotland Technical College and then, from 1871 to 1876, at Anderson's College, Glasgow, and at the Yorkshire College of Science, Leeds. Here he worked under and then became assistant to the distinguished chemist T.E.Thorpe, who set him to work on the fractional distillation of petroleum, which was to be useful to him in his later work. At that time he had intended to become a chemical engineer, but seeing a Lenoir gas engine at work, after his return to Glasgow, turned his main interest to gas and other internal combustion engines. He pursued his investigations first at Thomson, Sterne \& Company (1877–85) and then at Tangyes of Birmingham (1886–88. In 1888 he began a lifelong partnership in Marks and Clerk, consulting engineers and patent agents, in London.
    Beginning his work on gas engines in 1876, he achieved two patents in the two following years. In 1878 he made his principal invention, patented in 1881, of an engine working on the two-stroke cycle, in which the piston is powered during each revolution of the crankshaft, instead of alternate revolutions as in the Otto four-stroke cycle. In this engine, Clerk introduced supercharging, or increasing the pressure of the air intake. Many engines of the Clerk type were made but their popularity waned after the patent for the Otto engine expired in 1890. Interest was later revived, particularly for application to large gas engines, but Clerk's engine eventually came into its own where simple, low-power motors are needed, such as in motor cycles or motor mowers.
    Clerk's work on the theory and design of gas engines bore fruit in the book The Gas Engine (1886), republished with an extended text in 1909 as The Gas, Petrol and Oil Engine; these and a number of papers in scientific journals won him international renown. During and after the First World War, Clerk widened the scope of his interests and served, often as chairman, on many bodies in the field of science and industry.
    [br]
    Principal Honours and Distinctions
    Knighted 1917; FRS 1908; Royal Society Royal Medal 1924; Royal Society of Arts Alber Medal 1922.
    Further Reading
    Obituary Notices of Fellows of the Royal Society, no. 2, 1933.
    LRD

    Biographical history of technology > Clerk, Sir Dugald

  • 44 Cubitt, William

    [br]
    b. 1785 Dilham, Norfolk, England
    d. 13 October 1861 Clapham Common, Surrey, England
    [br]
    English civil engineer and contractor.
    [br]
    The son of a miller, he received a rudimentary education in the village school. At an early age he was helping his father in the mill, and in 1800 he was apprenticed to a cabinet maker. After four years he returned to work with his father, but, preferring to leave the parental home, he not long afterwards joined a firm of agricultural-machinery makers in Swanton in Norfolk. There he acquired a reputation for making accurate patterns for the iron caster and demonstrated a talent for mechanical invention, patenting a self-regulating windmill sail in 1807. He then set up on his own as a millwright, but he found he could better himself by joining the engineering works of Ransomes of Ipswich in 1812. He was soon appointed their Chief Engineer, and after nine years he became a partner in the firm until he moved to London in 1826. Around 1818 he invented the treadmill, with the aim of putting prisoners to useful work in grinding corn and other applications. It was rapidly adopted by the principal prisons, more as a means of punishment than an instrument of useful work.
    From 1814 Cubitt had been gaining experience in civil engineering, and upon his removal to London his career in this field began to take off. He was engaged on many canal-building projects, including the Oxford and Liverpool Junction canals. He accomplished some notable dock works, such as the Bute docks at Cardiff, the Middlesborough docks and the coal drops on the river Tees. He improved navigation on the river Severn and compiled valuable reports on a number of other leading rivers.
    The railway construction boom of the 1840s provided him with fresh opportunities. He engineered the South Eastern Railway (SER) with its daringly constructed line below the cliffs between Folkestone and Dover; the railway was completed in 1843, using massive charges of explosive to blast a way through the cliffs. Cubitt was Consulting Engineer to the Great Northern Railway and tried, with less than his usual success, to get the atmospheric system to work on the Croydon Railway.
    When the SER began a steamer service between Folkestone and Boulogne, Cubitt was engaged to improve the port facilities there and went on to act as Consulting Engineer to the Boulogne and Amiens Railway. Other commissions on the European continent included surveying the line between Paris and Lyons, advising the Hanoverian government on the harbour and docks at Hamburg and directing the water-supply works for Berlin.
    Cubitt was actively involved in the erection of the Crystal Palace for the Great Exhibition of 1851; in recognition of this work Queen Victoria knighted him at Windsor Castle on 23 December 1851.
    Cubitt's son Joseph (1811–72) was also a notable civil engineer, with many railway and harbour works to his credit.
    [br]
    Principal Honours and Distinctions
    Knighted 1851. FRS 1830. President, Institution of Civil Engineers 1850 and 1851.
    Further Reading
    LRD

    Biographical history of technology > Cubitt, William

  • 45 Ewing, Sir James Alfred

    [br]
    b. 27 March 1855 Dundee, Scotland
    d. 1935
    [br]
    Scottish engineer and educator.
    [br]
    Sir Alfred Ewing was one of the leading engineering academics of his generation. He was the son of a minister in the Free Church of Scotland, and was educated at Dundee High School and Edinburgh University, where he studied engineering under Professor Fleeming Jenkin. On Jenkin's nomination, Ewing was recruited as Professor of Mechanical Engineering at the University of Tokyo, where he spent five years from 1878 to 1883. While in Tokyo, he devised an instrument for measuring and recording earthquakes. Ewing returned to his home town of Dundee in 1883, as the first Professor of Engineering at the University College recently established there. After seven years building up the department in Dundee, he moved to Cambridge where he succeeded James Stuart as Professor of Mechanism and Applied Mechanics. In thirteen creative years at Cambridge, he established the Engineering Tripos (1892) and founded the first engineering laboratories at the University (1894). From 1903 to 1917 Ewing served the Admiralty as Director of Naval Education, in which role he took a leading part in the revolution in British naval traditions which equipped the Royal Navy to fight the First World War. In that war, Ewing made an important contribution to the intelligence operation of deciphering enemy wireless messages. In 1916 he returned to Edinburgh as Principal and Vice-Chancellor, and following the war he presided over a period of rapid expansion at the University. He retired in 1929.
    [br]
    Principal Honours and Distinctions
    FRS 1887. KCB 1911. President, British Association for the Advancement of Science 1932.
    Bibliography
    He wrote extensively on technical subjects, and his works included Thermodynamics for Engineers (1920). His many essays and papers on more general subjects are elegantly and attractively written.
    Further Reading
    Dictionary of National Biography Supplement.
    A.W.Ewing, 1939, Life of Sir Alfred Ewing (biography by his son).
    AB

    Biographical history of technology > Ewing, Sir James Alfred

  • 46 Fessenden, Reginald Aubrey

    [br]
    b. 6 October 1866 East Bolton, Quebec, Canada
    d. 22 July 1932 Bermuda
    [br]
    Canadian radio pioneer who made the first known broadcast of speech and music.
    [br]
    After initial education at Trinity College School, Port Hope, Ontario, Fessenden studied at Bishops University, Lennoxville, Quebec. When he graduated in 1885, he became Principal of the Whitney Institute in Bermuda, but he left the following year to go to New York in pursuit of his scientific interests. There he met Edison and eventually became Chief Chemist at the latter's Laboratory in Orange, New Jersey. In 1890 he moved to the Westinghouse Electric and Manufacturing Company, and two years later he returned to an academic career as Professor of Electrical Engineering, initially at Purdue University, Lafayette, Indiana, and then at the Western University of Pennsylvania, where he worked on wireless communication. From 1900 to 1902 he carried out experiments in wireless telegraphy at the US Weather Bureau, filing several patents relating to wire and liquid thermal detectors, or barretters. Following this he set up the National Electric Signalling Company; under his direction, Alexanderson and other engineers at the General Electric Company developed a high-frequency alternator that enabled him to build the first radiotelephony transmitter at Brant Rock, Massachusetts. This made its initial broadcast of speech and music on 24 December 1906, received by ship's wireless operators several hundred miles away. Soon after this the transmitter was successfully used for two-way wireless telegraphy communication with Scotland. Following this landmark event, Fessenden produced numerous inventions, including a radio compass, an acoustic depth-finder and several submarine signalling devices, a turboelectric drive for battleships and, notably, in 1912 the heterodyne principle used in radio receivers to convert signals to a lower (intermediate) frequency.
    [br]
    Principal Honours and Distinctions
    Institute of Electrical and Electronics Engineers Medal of Honour 1921.
    Bibliography
    US patents relating to barretters include nos. 706,740, 706,742 and 706,744 (wire, 1902) and 731,029 (liquid, 1903). His invention of the heterodyne was filed as US patent no. 1,050,441 (1913).
    Further Reading
    Helen M.Fessenden, 1940, Fessenden. Builder of Tomorrow. E.Hawkes, 1927, Pioneers of Wireless, London: Methuen. O.E.Dunlop, 1944, Radio's 100 Men of Science.
    KF

    Biographical history of technology > Fessenden, Reginald Aubrey

  • 47 Franklin, Benjamin

    [br]
    b. 17 January 1706 Boston, Massachusetts, USA
    d. 17 April 1790 Philadelphia, Pennsylvania, USA
    [br]
    American diplomat, statesman, scientist and inventor of bifocal spectacle lenses.
    [br]
    Described as a versatile genius, although less fairly also as an amateur dabbler, Franklin was of immediate English ancestry from Northamptonshire. During a long and prolific life, his innovations included the Franklin stove, arrangements for house ventilation and aeronautical and electrical experimentation. He was awarded the Copley Medal of the Royal Society in 1753 for his discoveries in relation to lighting conductors.
    His principal contribution to medicine was the invention of bifocal lenses constructed by the cementing of glass wafers to existing spectacle lenses. The date of this invention is uncertain, but was probably c.1774. A letter he wrote to a friend in 1775 refers to Peter Dollond, of the London optical firm, who has sometimes been thought to have contemporaneously developed some form of bifocal lens. Franklin's invention of the lens was prompted by his own visual difficulties.
    [br]
    Principal Honours and Distinctions
    Royal Medical Society of Paris 1777. Medical Society of London 1787. Royal Society Copley Medal 1753.
    Bibliography
    1888, The Life of Benjamin Franklin, Written by Himself, Philadelphia.
    Further Reading
    C.van Dorek, 1938, Benjamin Franklin.
    H.Barty-King, 1986, Eyes Right, London.
    MG

    Biographical history of technology > Franklin, Benjamin

  • 48 Garforth, William Edward

    [br]
    b. 1845 Dukinfield, Cheshire, England
    d. 1 October 1921 Pontefract, Yorkshire, England
    [br]
    English colliery manager, pioneer in machine-holing and the safety of mines.
    [br]
    After Menzies conceived his idea of breaking off coal with machines in 1761, many inventors subsequently followed his proposals through into the practice of underground working. More than one century later, Garforth became one of the principal pioneers of machine-holing combined with the longwall method of working in order to reduce production costs and increase the yield of coal. Having been appointed agent to Pope \& Pearson's Collieries, West Yorkshire, in 1879, of which company he later became Managing Director and Chairman, he gathered a great deal of experience with different methods of cutting coal. The first disc machine was exhibited in London as early as 1851, and ten years later a pick machine was invented. In 1893 he introduced an improved type of deep undercutting machine, his "diamond" disc coal-cutter, driven by compressed air, which also became popular on the European continent.
    Besides the considerable economic advantages it created, the use of machinery for mining coal increased the safety of working in hard and thin seams. The improvement of safety in mining technology was always his primary concern, and as a result of his inventions and his many publications he became the leading figure in the British coal mining industry at the beginning of the twentieth century; safety lamps still carry his name. In 1885 he invented a firedamp detector, and following a severe explosion in 1886 he concentrated on coal-dust experiments. From the information he obtained of the effect of stone-dust on a coal-dust explosion he proposed the stone-dust remedy to prevent explosions of coal-dust. As a result of discussions which lasted for decades and after he had been entrusted with the job of conducting the British coal-dust experiments, in 1921 an Act made it compulsory in all mines which were not naturally wet throughout to treat all roads with incombustible dust so as to ensure that the dust always consisted of a mixture containing not more than 50 per cent combustible matter. In 1901 Garforth erected a surface gallery which represented the damaged roadways of a mine and could be filled with noxious fumes to test self-contained breathing apparata. This gallery formed the model from which all the rescue-stations existing nowadays have been developed.
    [br]
    Principal Honours and Distinctions
    Knighted 1914. LLD Universities of Birmingham and Leeds 1912. President, Midland Institute 1892–4. President, The Institution of Mining Engineers 1911–14. President, Mining Association of Great Britain 1907–8. Chairman, Standing Committee on Mining, Advisory Council for Scientific and Industrial Research. Fellow of the Geological Society of London. North of England Institute of Mining and Mechanical Engineers Greenwell Silver Medal 1907. Royal Society of Arts Fothergill Gold Medal 1910. Medal of the Institution of Mining Engineers 1914.
    Bibliography
    1901–2, "The application of coal-cutting machines to deep mining", Transactions of the Federated Institute of Mining Engineers 23: 312–45.
    1905–6, "A new apparatus for rescue-work in mines", Transactions of the Institution of Mining Engineers 31:625–57.
    1902, "British Coal-dust Experiments". Paper communicated to the International Congress on Mining, Metallurgy, Applied Mechanics and Practical Geology, Dusseldorf.
    Further Reading
    Garforth's name is frequently mentioned in connection with coal-holing, but his outstanding achievements in improving safety in mines are only described in W.D.Lloyd, 1921, "Memoir", Transactions of the Institution of Mining Engineers 62:203–5.
    WK

    Biographical history of technology > Garforth, William Edward

  • 49 Lodge, Sir Oliver Joseph

    [br]
    b. 12 June 1851 Penkhull, Staffordshire, England
    d. 22 August 1940 Lake, near Salisbury, Wiltshire, England
    [br]
    English physicist who perfected Branly's coherer; said to have given the first public demonstration of wireless telegraphy.
    [br]
    At the age of 8 Lodge entered Newport Grammar School, and in 1863–5 received private education at Coombs in Suffolk. He then returned to Staffordshire, where he assisted his father in the potteries by working as a book-keeper. Whilst staying with an aunt in London in 1866–7, he attended scientific lectures and became interested in physics. As a result of this and of reading copies of English Mechanic magazine, when he was back home in Hanley he began to do experiments and attended the Wedgewood Institute. Returning to London c. 1870, he studied initially at the Royal College of Science and then, from 1874, at University College, London (UCL), at the same time attending lectures at the Royal Institution.
    In 1875 he obtained his BSc, read a paper to the British Association on "Nodes and loops in chemical formulae" and became a physics demonstrator at UCL. The following year he was appointed a physics lecturer at Bedford College, completing his DSc in 1877. Three years later he became Assistant Professor of Mathematics at UCL, but in 1881, after only two years, he accepted the Chair of Experimental Physics at the new University College of Liverpool. There began a period of fruitful studies of electricity and radio transmission and reception, including development of the lightning conductor, discovery of the "coherent" effect of sparks and improvement of Branly's coherer, and, in 1894, what is said to be the first public demonstration of the transmission and reception (using a coherer) of wireless telegraphy, from Lewis's department store to the clock tower of Liverpool University's Victoria Building. On 10 May 1897 he filed a patent for selective tuning by self-in-ductance; this was before Marconi's first patent was actually published and its priority was subsequently upheld.
    In 1900 he became the first Principal of the new University of Birmingham, where he remained until his retirement in 1919. In his later years he was increasingly interested in psychical research.
    [br]
    Principal Honours and Distinctions
    Knighted 1902. FRS 1887. Royal Society Council Member 1893. President, Society for Psychical Research 1901–4, 1932. President, British Association 1913. Royal Society Rumford Medal 1898. Royal Society of Arts Albert Medal 1919. Institution of Electrical Engineers Faraday Medal 1932. Fourteen honorary degrees from British and other universities.
    Bibliography
    1875, "The flow of electricity in a plane", Philosophical Magazine (May, June and December).
    1876, "Thermo-electric phenomena", Philosophical Magazine (December). 1888, "Lightning conductors", Philosophical Magazine (August).
    1889, Modern Views of Electricity (lectures at the Royal Institution).
    10 May 1897, "Improvements in syntonized telegraphy without line wires", British patent no. 11,575, US patent no. 609,154.
    1898, "Radio waves", Philosophical Magazine (August): 227.
    1931, Past Years, An Autobiography, London: Hodder \& Stoughton.
    Further Reading
    W.P.Jolly, 1974, Sir Oliver Lodge, Psychical Resear cher and Scientist, London: Constable.
    E.Hawks, 1927, Pioneers of Wireless, London: Methuen.
    KF

    Biographical history of technology > Lodge, Sir Oliver Joseph

  • 50 Marsden, Samuel

    [br]
    b. 1764 Parsley, Yorkshire, England
    d. 1838 Australia
    [br]
    English farmer whose breeding programme established the Australian wool industry.
    [br]
    Although his father was a farmer, at the age of 10 Samuel Marsden went to work as a blacksmith, and continued in that trade for ten years. He then decided to go into the Church, was educated at Hull Grammar School and Cambridge, and was ordained in 1793. He then emigrated to Australia, where he took up an appointment as Assistant Chaplain to the Colony. He was stationed at Parramatta, where he was granted 100 acres and bought a further 128 acres himself. In 1800 he became Principal Chaplain, and by 1802 he farmed the third largest farm in the colony. Initially he was able to obtain only two Marino rams and was forced to crossbreed with imported Indian stock. However, with this combination he was able to improve wool quality dramatically, and this stock provided the basis of his breeding stock. In 1807 he returned to Britain, taking 160 lb of wool with him. This was woven into 40 yards (36.5 m) of cloth in a mill near Leeds, and from this Marsden had a suit made which he wore when he visited George III. The latter was so impressed with the cloth that he presented Marsden with five Marino ewes in lamb, with which he returned to Australia. By 1811 he was sending more than 5,000 lb of wool back to the UK each year. In 1814 Marsden concentrated more on Church matters and made the first of seven missionary visits to New Zealand. He made the last of these excursions the year before his death.
    [br]
    Principal Honours and Distinctions
    Vice-President, New South Wales Agricultural Society (on its foundation) 1821.
    Further Reading
    Michael Ryder, 1983, Sheep and Man, Duckworth (a definitive study on sheep history that deals in detail with Marsden's developments).
    AP

    Biographical history of technology > Marsden, Samuel

  • 51 Preece, Sir William Henry

    [br]
    b. 15 February 1834 Bryn Helen, Gwynedd, Wales
    d. 6 November 1913 Penrhos, Gwynedd, Wales
    [br]
    Welsh electrical engineer who greatly furthered the development and use of wireless telegraphy and the telephone in Britain, dominating British Post Office engineering during the last two decades of the nineteenth century.
    [br]
    After education at King's College, London, in 1852 Preece entered the office of Edwin Clark with the intention of becoming a civil engineer, but graduate studies at the Royal Institution under Faraday fired his enthusiasm for things electrical. His earliest work, as connected with telegraphy and in particular its application for securing the safe working of railways; in 1853 he obtained an appointment with the Electric and National Telegraph Company. In 1856 he became Superintendent of that company's southern district, but four years later he moved to telegraph work with the London and South West Railway. From 1858 to 1862 he was also Engineer to the Channel Islands Telegraph Company. When the various telegraph companies in Britain were transferred to the State in 1870, Preece became a Divisional Engineer in the General Post Office (GPO). Promotion followed in 1877, when he was appointed Chief Electrician to the Post Office. One of the first specimens of Bell's telephone was brought to England by Preece and exhibited at the British Association meeting in 1877. From 1892 to 1899 he served as Engineer-in-Chief to the Post Office. During this time he made a number of important contributions to telegraphy, including the use of water as part of telegraph circuits across the Solent (1882) and the Bristol Channel (1888). He also discovered the existence of inductive effects between parallel wires, and with Fleming showed that a current (thermionic) flowed between the hot filament and a cold conductor in an incandescent lamp.
    Preece was distinguished by his administrative ability, some scientific insight, considerable engineering intuition and immense energy. He held erroneous views about telephone transmission and, not accepting the work of Oliver Heaviside, made many errors when planning trunk circuits. Prior to the successful use of Hertzian waves for wireless communication Preece carried out experiments, often on a large scale, in attempts at wireless communication by inductive methods. These became of historic interest only when the work of Maxwell and Hertz was developed by Guglielmo Marconi. It is to Preece that credit should be given for encouraging Marconi in 1896 and collaborating with him in his early experimental work on radio telegraphy.
    While still employed by the Post Office, Preece contributed to the development of numerous early public electricity schemes, acting as Consultant and often supervising their construction. At Worcester he was responsible for Britain's largest nineteenth-century public hydro-electric station. He received a knighthood on his retirement in 1899, after which he continued his consulting practice in association with his two sons and Major Philip Cardew. Preece contributed some 136 papers and printed lectures to scientific journals, ninety-nine during the period 1877 to 1894.
    [br]
    Principal Honours and Distinctions
    CB 1894. Knighted (KCB) 1899. FRS 1881. President, Society of Telegraph Engineers, 1880. President, Institution of Electrical Engineers 1880, 1893. President, Institution of Civil Engineers 1898–9. Chairman, Royal Society of Arts 1901–2.
    Bibliography
    Preece produced numerous papers on telegraphy and telephony that were presented as Royal Institution Lectures (see Royal Institution Library of Science, 1974) or as British Association reports.
    1862–3, "Railway telegraphs and the application of electricity to the signaling and working of trains", Proceedings of the ICE 22:167–93.
    Eleven editions of Telegraphy (with J.Sivewright), London, 1870, were published by 1895.
    1883, "Molecular radiation in incandescent lamps", Proceedings of the Physical Society 5: 283.
    1885. "Molecular shadows in incandescent lamps". Proceedings of the Physical Society 7: 178.
    1886. "Electric induction between wires and wires", British Association Report. 1889, with J.Maier, The Telephone.
    1894, "Electric signalling without wires", RSA Journal.
    Further Reading
    J.J.Fahie, 1899, History of Wireless Telegraphy 1838–1899, Edinburgh: Blackwood. E.Hawkes, 1927, Pioneers of Wireless, London: Methuen.
    E.C.Baker, 1976, Sir William Preece, F.R.S. Victorian Engineer Extraordinary, London (a detailed biography with an appended list of his patents, principal lectures and publications).
    D.G.Tucker, 1981–2, "Sir William Preece (1834–1913)", Transactions of the Newcomen Society 53:119–36 (a critical review with a summary of his consultancies).
    GW / KF

    Biographical history of technology > Preece, Sir William Henry

  • 52 Rawcliffe, Gordon Hindle

    SUBJECT AREA: Electricity
    [br]
    b. 2 June 1910 Sheffield, England
    d. 3 September 1979 Bristol, England
    [br]
    English scientist and inventor of the multi-speed induction motor using the pole amplitude modulation principle.
    [br]
    After graduating from Keble College, Oxford, Rawcliffe joined the Metropolitan Vickers Electrical Company in 1932 as a college apprentice, and later became a design engineer. This was followed by a period as a lecturer at Liverpool University, where he was able to extend his knowledge of the principles underlying the design and operation of electrical machines. In 1941 he became Head of the Electrical Engineering Department at the Robert Gordon Technical College, Aberdeen, and Lecturer in charge of Electrical Engineering at Aberdeen University. In 1944 Rawcliffe was appointed to the Chair of Electrical Engineering at the University of Bristol, where he remained until his retirement in 1975. The reputation of his department was enhanced by the colleagues he recruited.
    After 1954 he began research into polyphase windings, the basis of alternating-current machinery, and published papers concerned with the dual problems of frequency changing and pole changing. The result of this research was the discovery in 1957 of a technique for making squirrel-cage induction motors run at more than one speed. By reversing current in one part of the winding, the pole distribution and number were changed, and with it the speed of rotation.
    Rawcliffe's name became synonymous with pole amplitude modulation, or PAM, the name given to this technique. Described by Rawcliffe as a new philosophy of windings, the technique led to a series of research papers, patents and licensing agreements in addition to consultancies to advise on application problems. Commercial exploitation of the new idea throughout Western Europe, the United Kingdom and the United States followed. In total he contributed twentyfive papers to the Proceedings of the Institution of Electrical Engineers and some sixty British patent applications were filed.
    [br]
    Principal Honours and Distinctions
    FRS 1972. Royal Society S.G.Brown Medal 1978.
    Bibliography
    21 August 1958, British patent no. 900,600 (pole amplitude modulation).
    1958, with R.F.Burbridge and W.Fong, "Induction motor speed changing by pole amplitude modulation", Proceedings of the Institution of Electrical Engineers 105 (Part A): 411–19 (the first description of pole amplitude modulation).
    Further Reading
    Biographical Memoirs of Fellows of the Royal Society, 1981, Vol. XXVII, London, pp. 479–503 (includes lists of Rawcliffe's patents and principal papers published).
    GW

    Biographical history of technology > Rawcliffe, Gordon Hindle

  • 53 Rickover, Admiral Hyman George

    [br]
    b. 27 January 1900 Russian Poland
    d. 8 July 1986 Arlington, Virginia, USA
    [br]
    Polish/American naval officer, one of the principal architects of the United States nuclear submarine programme.
    [br]
    Born in Poland, Rickover was brought to the United States early in his life by his father, who settled in Chicago as a tailor. Commissioned into the US Navy in 1922, he specialized in electrical engineering (graduating from the US Naval Postgraduate School, Columbia, in 1929), quali-fied as a Submariner in 1931 and then held various posts until appointed Head of the Electrical Section of the Bureau of Ships in 1939. He held this post until the end of the Second World War.
    Rickover was involved briefly in the "Manhattan" atomic bomb project before being assigned to an atomic energy submarine project in 1946. Ultimately he was made responsible for the development and building of the world's first nuclear submarine, the USS Nautilus. He was convinced of the need to make the nuclear submarine an instrument of strategic importance, and this led to the development of the ballistic missile submarine and the Polaris programme.
    Throughout his career he was no stranger to controversy; indeed, his remaining on the active service list as a full admiral until the age of 82 (when forced to retire on the direct intervention of the Navy Secretary) indicates a man beyond the ordinary. He imposed his will on all around him and backed it with a brilliant and clear-thinking brain; his influence was even felt by the Royal Navy during the building of the first British nuclear submarine, HMS Dreadnought. He made many friends, but he also had many detractors.
    [br]
    Principal Honours and Distinctions
    US Distinguished Service Medal with Gold Star. Honorary CBE. US Congress Special Gold Medal 1959. Numerous awards and honorary degrees.
    Bibliography
    Rickover wrote several treatises on education and on the education of engineers. He also wrote on several aspects of the technical history of the US Navy.
    Further Reading
    W.R.Anderson and C.Blair, 1959, Nautilus 90 North, London: Hodder \& Stoughton. E.L.Beach, 1986, The United States Navy, New York: Henry Holt.
    FMW

    Biographical history of technology > Rickover, Admiral Hyman George

  • 54 Telford, Thomas

    SUBJECT AREA: Canals, Civil engineering
    [br]
    b. 9 August 1757 Glendinning, Dumfriesshire, Scotland
    d. 2 September 1834 London, England.
    [br]
    Scottish civil engineer.
    [br]
    Telford was the son of a shepherd, who died when the boy was in his first year. Brought up by his mother, Janet Jackson, he attended the parish school at Westerkirk. He was apprenticed to a stonemason in Lochmaben and to another in Langholm. In 1780 he walked from Eskdale to Edinburgh and in 1872 rode to London on a horse that he was to deliver there. He worked for Sir William Chambers as a mason on Somerset House, then on the Eskdale house of Sir James Johnstone. In 1783–4 he worked on the new Commissioner's House and other buildings at Portsmouth dockyard.
    In late 1786 Telford was appointed County Surveyor for Shropshire and moved to Shrewsbury Castle, with work initially on the new infirmary and County Gaol. He designed the church of St Mary Magdalene, Bridgnorth, and also the church at Madley. Telford built his first bridge in 1790–2 at Montford; between 1790 and 1796 he built forty-five road bridges in Shropshire, including Buildwas Bridge. In September 1793 he was appointed general agent, engineer and architect to the Ellesmere Canal, which was to connect the Mersey and Dee rivers with the Severn at Shrewsbury; William Jessop was Principal Engineer. This work included the Pont Cysyllte aqueduct, a 1,000 ft (305 m) long cast-iron trough 127 ft (39 m) above ground level, which entailed an on-site ironworks and took ten years to complete; the aqueduct is still in use today. In 1800 Telford put forward a plan for a new London Bridge with a single cast-iron arch with a span of 600 ft (183 m) but this was not built.
    In 1801 Telford was appointed engineer to the British Fisheries Society "to report on Highland Communications" in Scotland where, over the following eighteen years, 920 miles (1,480 km) of new roads were built, 280 miles (450 km) of the old military roads were realigned and rebuilt, over 1,000 bridges were constructed and much harbour work done, all under Telford's direction. A further 180 miles (290 km) of new roads were also constructed in the Lowlands of Scotland. From 1804 to 1822 he was also engaged on the construction of the Caledonian Canal: 119 miles (191 km) in all, 58 miles (93 km) being sea loch, 38 miles (61 km) being Lochs Lochy, Oich and Ness, 23 miles (37 km) having to be cut.
    In 1808 he was invited by King Gustav IV Adolf of Sweden to assist Count Baltzar von Platen in the survey and construction of a canal between the North Sea and the Baltic. Telford surveyed the 114 mile (183 km) route in six weeks; 53 miles (85 km) of new canal were to be cut. Soon after the plans for the canal were completed, the King of Sweden created him a Knight of the Order of Vasa, an honour that he would have liked to have declined. At one time some 60,000 soldiers and seamen were engaged on the work, Telford supplying supervisors, machinery—including an 8 hp steam dredger from the Donkin works and machinery for two small paddle boats—and ironwork for some of the locks. Under his direction an ironworks was set up at Motala, the foundation of an important Swedish industrial concern which is still flourishing today. The Gotha Canal was opened in September 1832.
    In 1811 Telford was asked to make recommendations for the improvement of the Shrewsbury to Holyhead section of the London-Holyhead road, and in 1815 he was asked to survey the whole route from London for a Parliamentary Committee. Construction of his new road took fifteen years, apart from the bridges at Conway and over the Menai Straits, both suspension bridges by Telford and opened in 1826. The Menai bridge had a span of 579 ft (176 m), the roadway being 153 ft (47 m) above the water level.
    In 1817 Telford was appointed Engineer to the Exchequer Loan Commission, a body set up to make capital loans for deserving projects in the hard times that followed after the peace of Waterloo. In 1820 he became the first President of the Engineers Institute, which gained its Royal Charter in 1828 to become the Institution of Civil Engineers. He was appointed Engineer to the St Katharine's Dock Company during its construction from 1825 to 1828, and was consulted on several early railway projects including the Liverpool and Manchester as well as a number of canal works in the Midlands including the new Harecastle tunnel, 3,000 ft (914 m) long.
    Telford led a largely itinerant life, living in hotels and lodgings, acquiring his own house for the first time in 1821, 24 Abingdon Street, Westminster, which was partly used as a school for young civil engineers. He died there in 1834, after suffering in his later years from the isolation of deafness. He was buried in Westminster Abbey.
    [br]
    Principal Honours and Distinctions
    FRSE 1803. Knight of the Order of Vasa, Sweden 1808. FRS 1827. First President, Engineers Insitute 1820.
    Further Reading
    L.T.C.Rolt, 1979, Thomas Telford, London: Penguin.
    C.Hadfield, 1993, Thomas Telford's Temptation, London: M. \& M.Baldwin.
    IMcN

    Biographical history of technology > Telford, Thomas

  • 55 Tizard, Sir Henry Thoms

    SUBJECT AREA: Weapons and armour
    [br]
    b. 23 August 1885 Gillingham, Kent, England
    d. 9 October 1959 Fareham, Hampshire, England
    [br]
    English scientist and administrator who made many contributions to military technology.
    [br]
    Educated at Westminster College, in 1904 Tizard went to Magdalen College, Oxford, gaining Firsts in mathematics and chemistry. After a period of time in Berlin with Nernst, he joined the Royal Institution in 1909 to study the colour changes of indicators. From 1911 until 1914 he was a tutorial Fellow of Oriel College, Oxford, but with the outbreak of the First World War he joined first the Royal Garrison Artillery, then, in 1915, the newly formed Royal Flying Corps, to work on the development of bomb-sights. Successively in charge of testing aircraft, a lieutenant-colonel in the Ministry of Munitions and Assistant Controller of Research and Experiments for the Royal Air Force, he returned to Oxford in 1919 and the following year became Reader in Chemical Thermodynamics; at this stage he developed the use of toluene as an air-craft-fuel additive.
    In 1922 he was appointed an assistant secretary at the government Department of Industrial and Scientific Research, becoming Principal Assistant Secretary in 1922 and its Permanent Director in 1927; during this time he was also a member of the Aeronautical Research Committee, being Chairman of the latter in 1933–43. From 1929 to 1942 he was Rector of Imperial College. In 1932 he was also appointed Chairman of a committee set up to investigate possible national air-defence systems, and it was largely due to his efforts that the radar proposals of Watson-Watt were taken up and an effective system made operational before the outbreak of the Second World War. He was also involved in various other government activities aimed at applying technology to the war effort, including the dam-buster and atomic bombs.
    President of Magdalen College in 1942–7, he then returned again to Whitehall, serving as Chairman of the Advisory Council on Scientific Policy and of the Defence Research Policy Committee. Finally, in 1952, he became Pro-Chan-cellor of Southampton University.
    [br]
    Principal Honours and Distinctions
    Air Force Cross 1918. CB 1927. KCB 1937. GCB 1949. American Medal of Merit 1947. FRS 1926. Ten British and Commonwealth University honorary doctorates. Hon. Fellowship of the Royal Aeronautical Society. Royal Society of Arts Gold Medal. Franklin Institute Gold Medal. President, British Association 1948. Trustee of the British Museum 1937–59.
    Bibliography
    1911, The sensitiveness of indicators', British Association Report (describes Tizard's work on colour changes in indicators).
    Further Reading
    KF

    Biographical history of technology > Tizard, Sir Henry Thoms

  • 56 Watson, George Lennox

    SUBJECT AREA: Ports and shipping
    [br]
    b. 1851 Glasgow, Scotland
    d. 12 November 1904 Glasgow, Scotland
    [br]
    Scottish designer of some of the world's largest sailing and powered yachts, principal technical adviser to the Royal National Lifeboat Institution.
    [br]
    Almost all of Watson's life was spent in or around the City of Glasgow; his formal education was at the city's High School and at the age of 16 he entered the yard and drawing offices of Robert Napier's Govan Shipyard. Three years later he crossed the River Clyde and started work in the design office of the Pointhouse Shipyard of A. \& J.Inglis, and there received the necessary grounding of a naval architect. Dr John Inglis, the Principal of the firm, encouraged Watson, ensured that he was involved in advanced design work and allowed him to build a yacht in a corner of the shipyard in his spare time.
    At the early age of 22 Watson set up as a naval architect with his own company, which is still in existence 120 years later. In 1875, assisted by two carpenters, Watson built the 5-ton yacht Vril to his own design. This vessel was the first with an integral heavy lead keel and its success ensured that design contracts flowed to him for new yachts for the Clyde and elsewhere. His enthusiasm and increasing skill were recognized and soon he was working on the ultimate: the America's Cup challengers Thistle, Valkyrie II, Valkyrie III and Shamrock II. The greatest accolade was the contract for the design of the J Class yacht Britannia, built by D. \& W.Henderson of Glasgow in 1893 for the Prince of Wales.
    The company of G.L.Watson became the world's leading designer of steam yachts, and it was usual for it to offer a full design service as well as supervise construction in any part of the world. Watson took a deep interest in the work of the Royal National Lifeboat Institution and was its technical consultant for many years. One of his designs, the Watson Lifeboat, was a stalwart in its fleet for many years. In public life he lectured, took an active part in the debates on yacht racing and was recognized as Britain's leading designer.
    [br]
    Bibliography
    1881, Progress in Yachting and Yacht-Building, Glasgow Naval and Marine Engineering Catalogue, London and Glasgow: Collins.
    1894, The Evolution of the Modern Racing Yacht, Badminton Library of Sports and Pastimes, Vol. 1, London: Longmans Green, pp. 54–109.
    Further Reading
    John Irving, 1937, The King's Britannia. The Story of a Great Ship, London: Seeley Service.
    FMW

    Biographical history of technology > Watson, George Lennox

  • 57 Watt, James

    [br]
    b. 19 January 1735 Greenock, Renfrewshire, Scotland
    d. 19 August 1819 Handsworth Heath, Birmingham, England
    [br]
    Scottish engineer and inventor of the separate condenser for the steam engine.
    [br]
    The sixth child of James Watt, merchant and general contractor, and Agnes Muirhead, Watt was a weak and sickly child; he was one of only two to survive childhood out of a total of eight, yet, like his father, he was to live to an age of over 80. He was educated at local schools, including Greenock Grammar School where he was an uninspired pupil. At the age of 17 he was sent to live with relatives in Glasgow and then in 1755 to London to become an apprentice to a mathematical instrument maker, John Morgan of Finch Lane, Cornhill. Less than a year later he returned to Greenock and then to Glasgow, where he was appointed mathematical instrument maker to the University and was permitted in 1757 to set up a workshop within the University grounds. In this position he came to know many of the University professors and staff, and it was thus that he became involved in work on the steam engine when in 1764 he was asked to put in working order a defective Newcomen engine model. It did not take Watt long to perceive that the great inefficiency of the Newcomen engine was due to the repeated heating and cooling of the cylinder. His idea was to drive the steam out of the cylinder and to condense it in a separate vessel. The story is told of Watt's flash of inspiration as he was walking across Glasgow Green one Sunday afternoon; the idea formed perfectly in his mind and he became anxious to get back to his workshop to construct the necessary apparatus, but this was the Sabbath and work had to wait until the morrow, so Watt forced himself to wait until the Monday morning.
    Watt designed a condensing engine and was lent money for its development by Joseph Black, the Glasgow University professor who had established the concept of latent heat. In 1768 Watt went into partnership with John Roebuck, who required the steam engine for the drainage of a coal-mine that he was opening up at Bo'ness, West Lothian. In 1769, Watt took out his patent for "A New Invented Method of Lessening the Consumption of Steam and Fuel in Fire Engines". When Roebuck went bankrupt in 1772, Matthew Boulton, proprietor of the Soho Engineering Works near Birmingham, bought Roebuck's share in Watt's patent. Watt had met Boulton four years earlier at the Soho works, where power was obtained at that time by means of a water-wheel and a steam engine to pump the water back up again above the wheel. Watt moved to Birmingham in 1774, and after the patent had been extended by Parliament in 1775 he and Boulton embarked on a highly profitable partnership. While Boulton endeavoured to keep the business supplied with capital, Watt continued to refine his engine, making several improvements over the years; he was also involved frequently in legal proceedings over infringements of his patent.
    In 1794 Watt and Boulton founded the new company of Boulton \& Watt, with a view to their retirement; Watt's son James and Boulton's son Matthew assumed management of the company. Watt retired in 1800, but continued to spend much of his time in the workshop he had set up in the garret of his Heathfield home; principal amongst his work after retirement was the invention of a pantograph sculpturing machine.
    James Watt was hard-working, ingenious and essentially practical, but it is doubtful that he would have succeeded as he did without the business sense of his partner, Matthew Boulton. Watt coined the term "horsepower" for quantifying the output of engines, and the SI unit of power, the watt, is named in his honour.
    [br]
    Principal Honours and Distinctions
    FRS 1785. Honorary LLD, University of Glasgow 1806. Foreign Associate, Académie des Sciences, Paris 1814.
    Further Reading
    H.W.Dickinson and R Jenkins, 1927, James Watt and the Steam Engine, Oxford: Clarendon Press.
    L.T.C.Rolt, 1962, James Watt, London: B.T. Batsford.
    R.Wailes, 1963, James Watt, Instrument Maker (The Great Masters: Engineering Heritage, Vol. 1), London: Institution of Mechanical Engineers.
    IMcN

    Biographical history of technology > Watt, James

  • 58 Waymouth, Bernard

    SUBJECT AREA: Ports and shipping
    [br]
    b. unknown
    d. 25 November 1890 London, England
    [br]
    English naval architect, ship surveyor and designer of the clipper ship Thermopylae.
    [br]
    Waymouth had initial training in shipbuilding at one of the Royal Dockyards before going on to work at a privately owned shipyard. With this all-round experience he was accepted in 1854 by Lloyd's Register of Shipping as a surveyor, and was to serve the Society well during a period of great change in ship design. In 1864 he was charged with the task of framing the Rules for the Construction of Composite Built Vessels, i.e. ships with main structural members such as keel, frames and deck beams of iron and with the hull sheathing or planking of timber. Although long superseded, these rules were of considerable consequence at the time and they were accompanied by beautiful drawings executed by Harry J.Cornish, who became Chief Ship Surveyor of Lloyd's from 1900 until 1909. In 1870 revolutionary proposals were made for iron ships that led to the adoption of a new form of rules where the scantlings or size of individual parts were related to the overall dimensions of the vessel. The symbol 100A1 was then adopted for the first time.
    Waymouth was more than a theoretical naval architect: in the late 1860s he was commissioned by the shipbuilders Walter Hood to design the famous Aberdeen Clipper Thermopylae. This was one of the fastest sailing ships of the nineteenth century and, along with its Clyde-built counterpart Cutty Sark, proved the efficacy of composite construction for these specialist vessels.
    Waymouth was appointed Principal Surveyor of Lloyd's in 1870 and was Secretary of the Society from 1872 until his death at work in 1890. He was a member of the Royal Commission on Tonnage and of the Enquiry into the loss of HMS Atlanta, and at the time of his death was Vice-President of the Institution of Naval Architects.
    [br]
    Principal Honours and Distinctions
    Vice-President, Institution of Naval Architects.
    Further Reading
    Annals of Lloyd's Register, 1934, London.
    FMW

    Biographical history of technology > Waymouth, Bernard

  • 59 pokok

    subject, main, essence, underlying, centre
    * * *
    fundamental, fundamental
    * * *
    main, principal, basic, fundamental, base; beginning; capital, stake; subject; reason, central theme; tree; main or lower part of something

    Indonesia-Inggris kamus > pokok

  • 60 Ampère, André-Marie

    SUBJECT AREA: Electricity
    [br]
    b. 22 Jan 1775 Lyon, France
    d. 10 June 1836 Marseille, France
    [br]
    French physicist and mathematician who established laws and principles relating magnetism and electricity to each other.
    [br]
    Ampère was reputed to have mastered all the then-known mathematics by the age of 12. He became Professor of Physics and Chemistry at Bourg in 1801 and a professor of mathematics at the Ecole Polytechnique in Paris in 1809. Observing a demonstration in 1820 of Oersted's discovery that a magnetic needle was deflected when placed near a current-carrying wire, Ampère was inspired to investigate the subject of electricity, of which he had no previous experience. Within a week he had prepared the first of several important communications on his discoveries to the Academy of Sciences in Paris. Included was a new hypothesis formed on the basis of his experiments on the relation between electricity and magnetism. He investigated the forces exerted on each other by current-carrying conductors and the properties of a solenoid. His mathematical theory describing these phenomena provided the foundations for the development of electro-dynamics and his classic work Théorie mathématique des phénomènes électro-dynamiques was published in 1827.
    The name "ampere" was adopted to replace the name "weber" as a unit of current after Helmholtz proposed such a change in 1881.
    [br]
    Principal Honours and Distinctions
    Bibliography
    1827, Théorie mathématique des phénomènes électro-dynamiques, Paris; repub. 1958, Paris (his chief published work).
    Further Reading
    P.Lenard, 1933, Great Men of Science, London, pp. 223–30 (provides a short account). C.C.Gillispie (ed.), 1970, Dictionary of Scientific Biography, Vol. 1, New York, pp.
    139–46.
    GW

    Biographical history of technology > Ampère, André-Marie

См. также в других словарях:

  • Subject — Sub*ject , n. [From L. subjectus, through an old form of F. sujet. See {Subject}, a.] 1. That which is placed under the authority, dominion, control, or influence of something else. [1913 Webster] 2. Specifically: One who is under the authority… …   The Collaborative International Dictionary of English

  • principal — prin·ci·pal 1 / prin sə pəl/ adj 1: being the main or most important, consequential, or influential their principal place of business the principal obligor 2: of, relating to, or constituting principal or a principal the principal amount of the… …   Law dictionary

  • subject — n 1 *citizen, national Antonyms: sovereign 2 Subject, matter, subject matter, argument, topic, text, theme, motive, motif, leitmotiv can mean the basic idea or the principal object of thought or attention in a discourse or artistic composition.… …   New Dictionary of Synonyms

  • principal — [prin′sə pəl] adj. [OFr < L principalis < princeps: see PRINCE] 1. first in rank, authority, importance, degree, etc. 2. that is or has to do with PRINCIPAL (n. 3) n. 1. a principal person or thing; specif., a) a ch …   English World dictionary

  • subject — [adj] at the mercy of; answerable accountable, apt, at one’s feet*, bound by, captive, collateral, conditional, contingent, controlled, dependent, directed, disposed, enslaved, exposed, governed, in danger of, inferior, liable, likely, obedient,… …   New thesaurus

  • principal — adj Chief; leading; most important or considerable; primary; original. Highest in rank, authority, character, importance, or degree. As to principal challenge principal contract principal obligation principal office principal vein, see those… …   Black's law dictionary

  • Principal homogeneous space — In mathematics, a principal homogeneous space, or torsor, for a group G is a set X on which G acts freely and transitively. That is, X is a homogeneous space for G such that the stabilizer of any point is trivial. An analogous definition holds in …   Wikipedia

  • Principal at risk notes — What are Principal at Risk Notes? Ending Value Higher Benefits of PARs * Enhanced/Leveraged Return ** Upside: Receive a return that is enhanced by leverage so that it will be higher than the actually return, subject to any caps. ** Downside:… …   Wikipedia

  • principal — principalship, n. /prin seuh peuhl/, adj. 1. first or highest in rank, importance, value, etc.; chief; foremost. 2. of, of the nature of, or constituting principal or capital: a principal investment. 3. Geom. (of an axis of a conic) passing… …   Universalium

  • subject — subjectable, adj. subjectability, n. subjectedly, adv. subjectedness, n. subjectless, adj. subjectlike, adj. n., adj. /sub jikt/; v. /seuhb jekt /, n. 1. that which forms a basic matter of thought, discussion, investigation, etc.: a subject of… …   Universalium

  • subject — sub•ject n., adj. [[t]ˈsʌb dʒɪkt[/t]] v. [[t]səbˈdʒɛkt[/t]] n. 1) that which forms a basic matter of thought, discussion, investigation, etc 2) edu a branch of knowledge as a course of study 3) a motive, cause, or ground: a subject for… …   From formal English to slang

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