march+unit

SUBJECT AREA: Electronics and information technology, Telecommunications

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Baudot had no formal education beyond his local primary school and began his working life as a farmer, as was his father. However, in September 1869 he joined the French telegraph service and was soon sent on a course on the recently developed Hughes printing telegraph. After service in the Franco-Prussian war as a lieutenant with the military telegraph, he returned to his civilian duties in Paris in 1872. He was there encouraged to develop (in his own time!) a multiple Hughes system for time-multiplexing of several telegraph messages. By using synchronized clockwork-driven rotating switches at the transmitter and receiver he was able to transmit five messages simultaneously; the system was officially adopted by the French Post \& Telegraph Administration five years later. In 1874 he patented the idea of a 5-bit (i.e. 32-permutation) code, with equal on and off intervals, for telegraph transmission of the Roman alphabet and punctuation signs and for control of the typewriter-like teleprinter used to display the message. This code, known as the Baudot code, was found to be more economical than the existing Morse code and was widely adopted for national and international telegraphy in the twentieth century. In the 1970s it was superseded by 7—and 8-bit codes.

Further development of his ideas on multiplexing led in 1894 to methods suitable for high-speed telegraphy. To commemorate his contribution to efficient telegraphy, the unit of signalling speed (i.e. the number of elements transmitted per second) is known as the baud.

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SUBJECT AREA: Electronics and information technology

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Born on a cattle ranch, Forrester obtained a BSc in electrical engineering at the University of Nebraska in 1939 and his MSc at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, where he remained to teach and carry out research. Becoming interested in computing, he established the Digital Computer Laboratory at MIT in 1945 and became involved in the construction of Whirlwind I, an early general-purpose computer completed in March 1951 and used for flight-simulation by the US Army Air Force. Finding the linear memories then available for storing data a major limiting factor in the speed at which computers were able to operate, he developed a three-dimensional store based on the binary switching of the state of small magnetic cores that could be addressed and switched by a matrix of wires carrying pulses of current. The machine used parallel synchronous fixed-point computing, with fifteen binary digits and a plus sign, i.e. 16 bits in all, and contained 5,000 vacuum tubes, eleven semiconductors and a 2 MHz clock for the arithmetic logic unit. It occupied a two-storey building and consumed 150kW of electricity. From his experience with the development and use of computers, he came to realize their great potential for the simulation and modelling of real situations and hence for the solution of a variety of management problems, using data communications and the technique now known as interactive graphics. His later career was therefore in this field, first at the MIT Lincoln Laboratory in Lexington, Massachusetts (1951) and subsequently (from 1956) as Professor at the Sloan School of Management at the Massachusetts Institute of Technology.

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See also: Burks, Arthur Walter; Goldstine, Herman H.; Wilkes, Maurice Vincent; Williams, Sir Frederic Calland

SUBJECT AREA: Paper and printing

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Although reared in a farming community, Lanston was able to develop his mechanical talent. After serving in the American Civil War he secured a clerkship in the Pensions Office in Washington, where he remained for twenty-two years. He studied law in his spare time and was called to the Bar. At the same time, he invented a whole variety of mechanical devices, many of which he patented. Around 1883 Lanston began taking an interest in machines for composing printers' type, probably stimulated by Ottmar Mergenthaler, who was then in Washington and working in this field. Four years' work were rewarded on 7 June 1887 by the grant of a patent, followed by three more, for a machine "to produce justified lines of type". The machine, the Monotype, consisted of two components: first a keyboard unit produced a strip of paper tape with holes punched in patterns corresponding to the characters required; this tape controlled the matrices in the caster, the second and "hot metal" component, from which types were ejected singly and fed to an assembly point until a complete line of type had been formed. Lanston resigned his post and set up the Lanston Type Machine Company in Washington. He laboured for ten years to convert the device defined in his patents into a machine that could be made and used commercially. In 1897 the perfected Monotype appeared. The company was reorganized as the Lanston Monotype Manufacturing Company of Philadelphia, and Lanston devoted himself to promoting and improving the machine. Monotype, with Mergenthaler's Linotype, steadily supplanted hand-setting and the various inadequate mechanical methods that were then in use, and by the 1920s they reigned supreme, until the 1960s, when they themselves began to be superseded by computer-controlled photosetting methods.

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SUBJECT AREA: Medical technology

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Following secondary education at Ashton-inMakerfield Grammar School, Randall entered Manchester University to read physics, gaining a first class BSc in 1925 and his MSc in 1926. From 1926 to 1937 he was a research physicist at the General Electric Company (GEC) laboratories, where he worked on luminescent powders, following which he became Warren Research Fellow of the Royal Society at Birmingham University, studying electronic processes in luminescent solids. With the outbreak of the Second World War he became an honorary member of the university staff and transferred to a group working on the development of centrimetric radar. With Boot he was responsible for the development of the cavity magnetron, which had a major impact on the development of radar.

When Birmingham resumed its atomic research programme in 1943, Randall became a temporary lecturer at the Cavendish Laboratory in Cambridge. The following year he was appointed Professor of Natural Philosophy at the University of St Andrews, but in 1946 he moved again to the Wheatstone Chair of Physics at King's College, London. There his developing interest in biophysical research led to the setting up of a multi-disciplinary group in 1951 to study connective tissues and other biological components, and in 1950– 5 he was joint Editor of Progress in Biophysics. From 1961 until his retirement in 1970 he was Professor of Biophysics at King's College and for most of that time he was also Chairman of the School of Biological Sciences. In addition, for many years he was honorary Director of the Medical Research Council Biophysics Research Unit.

After he retired he returned to Edinburgh and continued to study biological problems in the university zoology laboratory.

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SUBJECT AREA: Electronics and information technology, Horology, Land transport

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The son of G.W.C.Sinclair, a machine tool engineer, the young Sinclair's education was disrupted by the failure of his father's business. Aged 12 he left Boxgrove preparatory school and went through twelve more schools before leaving St George's School, Weybridge, at the age of 17. His first job was as an editorial assistant on a hobbyist's magazine, Practical Wireless, and his next as an editor at Bernard Books, writing a series of technical manuals. In 1961 he registered Sinclair Radionics and in the following year announced its first product, a micro-amplifier. This was the first of a series of miniaturized radio products that he put on the market while retaining his editorial job. In 1972 he launched the Sinclair Executive calculator, selling originally at £79.95 but later at £24.95. In 1976, the Black Watch, an electronic watch with digital light-emitting diode (LED) display, was marketed, to be followed by the TV1A, a miniature television with a 2 in. (5 cm) monochrome screen. During the latter part of this period, Sinclair Radionics was supported by investment from the UK National Enterprise Board, who appointed an outside managing director; after making a considerable loss, they closed the company in 1979. However, Sinclair Electronics had already been set up and started to market the UK's first cheap computer kit, the MK 14, which was followed by the ZX 80 and later the ZX 81. Price was kept at a minimum by the extensive use of existing components, though this was a restriction on performance. The small memory was enhanced from one kilobyte to seventeen kilobytes with the addition of a separate memory unit. In January 1985 Sinclair produced the Sinclair C5, a small three-wheeled vehicle driven by a washing-machine engine, intended as a revolutionary new form of personal transport; perceived as unsafe and impractical, it did not prove popular, and the failure of this venture resulted in a contraction of Sinclair's business activities. Later in 1985, a rival electronics company, Amstrad, paid £35,000,000 for all rights to existing Sinclair computer products.

In March 1992, the irrepressible Sinclair launched his latest brainchild, the Zike electric bicycle; a price of £499 was forecast. This machine, powered by an electric motor but with pedal assistance, had a top speed of 19 km/h (12 mph) and, on full power, would run for up to one hour. Its lightweight nickel-cadmium battery could be recharged either by a generator or by free-wheeling. Although more practical than the C5, it did not bring Sinclair success on the scale of his earlier micro-electronic products.

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SUBJECT AREA: Electricity

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Volta had an early command of English, French and Latin, and also learned to read Dutch and Spanish. After completing studies at the Royal Seminary in Como he was involved in the study of physics, chemistry and electricity. He became a teacher of physics in his native town and in 1779 was appointed Professor of Physics at the University of Pavia, a post he held for forty years.

With a growing international reputation and a wish to keep abreast of the latest developments, in 1777 he began the first of many travels abroad. A journey started in 1781 to Switzerland, Germany, Belgium, Holland, France and England lasted about one year. By 1791 he had been elected to membership of many learned societies, including those in Zurich, Berlin, Berne and Paris. Volta's invention of his pile resulted from a controversy with Luigi Galvani, Professor of Anatomy at the University of Bologna. Galvani discovered that the muscles of frogs' legs contracted when touched with two pieces of different metals and attributed this to a phenomenon of the animal tissue. Volta showed that the excitation was due to a chemical reaction resulting from the contact of the dissimilar metals when moistened. His pile comprised a column of zinc and silver discs, each pair separated by paper moistened with brine, and provided a source of continuous current from a simple and accessible source. The effectiveness of the pile decreased as the paper dried and Volta devised his crown of cups, which had a longer life. In this, pairs of dissimilar metals were placed in each of a number of cups partly filled with an electrolyte such as brine. Volta first announced the results of his experiments with dissimilar metals in 1800 in a letter to Sir Joseph Banks, President of the Royal Society. This letter, published in the Transactions of the Royal Society, has been regarded as one of the most important documents in the history of science. Large batteries were constructed in a number of laboratories soon after Volta's discoveries became known, leading immediately to a series of developments in electrochemistry and eventually in electromagnetism. Volta himself made little further contribution to science. In recognition of his achievement, at a meeting of the International Electrical Congress in Paris in 1881 it was agreed to name the unit of electrical pressure the "volt".

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