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81 Hertz, Heinrich Rudolph
[br]b. 22 February 1857 Hamburg, Germanyd. 1 January 1894 Bonn, Germany[br]German physicist who was reputedly the first person to transmit and receive radio waves.[br]At the age of 17 Hertz entered the Gelehrtenschule of the Johaneums in Hamburg, but he left the following year to obtain practical experience for a year with a firm of engineers in Frankfurt am Main. He then spent six months at the Dresden Technical High School, followed by year of military service in Berlin. At this point he decided to switch from engineering to physics, and after a year in Munich he studied physics under Helmholtz at the University of Berlin, gaining his PhD with high honours in 1880. From 1883 to 1885 he was a privat-dozent at Kiel, during which time he studied the electromagnetic theory of James Clerk Maxwell. In 1885 he succeeded to the Chair in Physics at Karlsruhe Technical High School. There, in 1887, he constructed a rudimentary transmitter consisting of two 30 cm (12 in.) rods with metal balls separated by a 7.5 mm (0.3 in.) gap at the inner ends and metallic plates at the outer ends, the whole assembly being mounted at the focus of a large parabolic metal mirror and the two rods being connected to an induction coil. At the other side of his laboratory he placed a 70 cm (27½ in.) diameter wire loop with a similar air gap at the focus of a second metal mirror. When the induction coil was made to create a spark across the transmitter air gap, he found that a spark also occurred at the "receiver". By a series of experiments he was not only able to show that the invisible waves travelled in straight lines and were reflected by the parabolic mirrors, but also that the vibrations could be refracted like visible light and had a similar wavelength. By this first transmission and reception of radio waves he thus confirmed the theoretical predictions made by Maxwell some twenty years earlier. It was probably in his experiments with this apparatus in 1887 that Hertz also observed that the voltage at which a spark was able to jump a gap was significantly reduced by the presence of ultraviolet light. This so-called photoelectric effect was subsequently placed on a theoretical basis by Albert Einstein in 1905. In 1889 he became Professor of Physics at the University of Bonn, where he continued to investigate the nature of electric discharges in gases at low pressure until his death after a long and painful illness. In recognition of his measurement of radio and other waves, the international unit of frequency of an oscillatory wave, the cycle per second, is now universally known as the Hertz.[br]Principal Honours and DistinctionsRoyal Society Rumford Medal 1890.BibliographyMuch of Hertz's work, including his 1890 paper "On the fundamental equations of electrodynamics for bodies at rest", is recorded in three collections of his papers which are available in English translations by D.E.Jones et al., namely Electric Waves (1893), Miscellaneous Papers (1896) and Principles of Mechanics (1899).Further ReadingJ.G.O'Hara and W.Pricha, 1987, Hertz and the Maxwellians, London: Peter Peregrinus. J.Hertz, 1977, Heinrich Hertz, Memoirs, Letters and Diaries, San Francisco: San Francisco Press.R.Appleyard, 1930, Pioneers of Electrical Communication.See also: Heaviside, OliverKFBiographical history of technology > Hertz, Heinrich Rudolph
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82 Lavoisier, Antoine Laurent
SUBJECT AREA: Chemical technology[br]b. 26 August 1743 Paris, Franced. 8 May 1794 Paris, France[br]French founder of the modern science of chemistry.[br]As well as receiving a formal education in law and literature, Lavoisier studied science under some of the leading figures of the day. This proved to be an ideal formation of the man in whom "man of science" and "public servant" were so intimately combined. His early work towards the first geological map of France and on the water supply of Paris helped to win him election to the Royal Academy of Sciences in 1768 at the youthful age of 25. In the same year he used some of his private income to buy a part-share in the "tax farm", a private company which leased from the Government the right to collect certain indirect taxes.In 1772 Lavoisier began his researches into the related phenomena of combustion, respiration and the calcination or oxidation of metals. This culminated in the early 1780s in the overthrow of the prevailing theory, based on an imponderable combustion principle called "phlogiston", and the substitution of the modern explanation of these processes. At the same time, understanding of the nature of acids, bases and salts was placed on a sounder footing. More important, Lavoisier defined a chemical element in its modern sense and showed how it should be applied by drawing up the first modern list of the chemical elements. With the revolution in chemistry initiated by Lavoisier, chemists could begin to understand correctly the fundamental processes of their science. This understanding was the foundationo of the astonishing advance in scientific and industrial chemistry that has taken place since then. As an academician, Lavoisier was paid by the Government to carry out investigations into a wide variety of practical questions with a chemical bias, such as the manufacture of starch and the distillation of phosphorus. In 1775 Louis XVI ordered the setting up of the Gunpowder Commission to improve the supply and quality of gunpowder, deficiencies in which had hampered France's war efforts. Lavoisier was a member of the Commission and, as usual, took the leading part, drawing up its report and supervising its implementation. As a result, the industry became profitable, output increased so that France could even export powder, and the range of the powder increased by two-thirds. This was a material factor in France's war effort in the Revolution and the Napoleonic wars.As if his chemical researches and official duties were not enough, Lavoisier began to apply his scientific principles to agriculture when he purchased an estate at Frechines, near Blois. After ten years' work on his experimental farm there, Lavoisier was able to describe his results in the memoir "Results of some agricultural experiments and reflections on their relation to political economy" (Paris, 1788), which holds historic importance in agriculture and economics. In spite of his services to the nation and to humanity, his association with the tax farm was to have tragic consequences: during the reign of terror in 1794 the Revolutionaries consigned to the guillotine all the tax farmers, including Lavoisier.[br]Bibliography1862–93, Oeuvres de Lavoisier, Vols I–IV, ed. J.B.A.Dumas; Vols V–VI, ed. E.Grimaux, Paris (Lavoisier's collected works).Further ReadingD.I.Duveen and H.S.Klickstein, 1954, A Bibliography of the Works of Antoine Laurent Lavoisier 1743–1794, London: William Dawson (contains valuable biographical material).D.McKie, 1952, Antoine Lavoisier, Scientist, Economist, Social Reformer, London: Constable (the best modern, general biography).H.Guerlac, 1975, Antoine Laurent Lavoisier, Chemist and Revolutionary, New York: Charles Scribner's Sons (a more recent work).LRDBiographical history of technology > Lavoisier, Antoine Laurent
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83 Williams, Sir Frederic Calland
SUBJECT AREA: Electronics and information technology[br]b. 26 June 1911 Stockport, Cheshire, Englandd. 11 August 1977 Prestbury, Cheshire, England[br]English electrical engineer who invented the Williams storage cathode ray tube, which was extensively used worldwide as a data memory in the first digital computers.[br]Following education at Stockport Grammar School, Williams entered Manchester University in 1929, gaining his BSc in 1932 and MSc in 1933. After a short time as a college apprentice with Metropolitan Vickers, he went to Magdalen College, Oxford, to study for a DPhil, which he was awarded in 1936. He returned to Manchester University that year as an assistant lecturer, gaining his DSc in 1939. Following the outbreak of the Second World War he worked for the Scientific Civil Service, initially at the Bawdsey Research Station and then at the Telecommunications Research Establishment at Malvern, Worcestershire. There he was involved in research on non-incandescent amplifiers and diode rectifiers and the development of the first practical radar system capable of identifying friendly aircraft. Later in the war, he devised an automatic radar system suitable for use by fighter aircraft.After the war he resumed his academic career at Manchester, becoming Professor of Electrical Engineering and Director of the University Electrotechnical Laboratory in 1946. In the same year he succeeded in developing a data-memory device based on the cathode ray tube, in which the information was stored and read by electron-beam scanning of a charge-retaining target. The Williams storage tube, as it became known, not only found obvious later use as a means of storing single-frame, still television images but proved to be a vital component of the pioneering Manchester University MkI digital computer. Because it enabled both data and program instructions to be stored in the computer, it was soon used worldwide in the development of the early stored-program computers.[br]Principal Honours and DistinctionsKnighted 1976. OBE 1945. CBE 1961. FRS 1950. Hon. DSc Durham 1964, Sussex 1971, Wales 1971. First Royal Society of Arts Benjamin Franklin Medal 1957. City of Philadelphia John Scott Award 1960. Royal Society Hughes Medal 1963. Institution of Electrical Engineers Faraday Medal 1972. Institute of Electrical and Electronics Engineers Pioneer Award 1973.BibliographyWilliams contributed papers to many scientific journals, including Proceedings of the Royal Society, Proceedings of the Cambridge Philosophical Society, Journal of the Institution of Electrical Engineers, Proceedings of the Institution of Mechanical Engineers, Wireless Engineer, Post Office Electrical Engineers' Journal. Note especially: 1948, with J.Kilburn, "Electronic digital computers", Nature 162:487; 1949, with J.Kilburn, "A storage system for use with binary digital computing machines", Proceedings of the Institution of Electrical Engineers 96:81; 1975, "Early computers at Manchester University", Radio \& Electronic Engineer 45:327. Williams also collaborated in the writing of vols 19 and 20 of the MIT RadiationLaboratory Series.Further ReadingB.Randell, 1973, The Origins of Digital Computers, Berlin: Springer-Verlag. M.R.Williams, 1985, A History of Computing Technology, London: Prentice-Hall. See also: Stibitz, George R.; Strachey, Christopher.KFBiographical history of technology > Williams, Sir Frederic Calland
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