also+mathematics)

SUBJECT AREA: Ports and shipping

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Froude was educated at a preparatory school at Buckfastleigh, and then at Westminster School, London, before entering Oriel College, Oxford, to read mathematics and classics. Between 1836 and 1838 he served as a pupil civil engineer, and then he joined the staff of Isambard Kingdom Brunel on various railway engineering projects in southern England, including the South Devon Atmospheric Railway. He retired from professional work in 1846 and lived with his invalid father at Dartington Parsonage. The next twenty years, while apparently unproductive, were important to Froude as he concentrated his mind on difficult mathematical and scientific problems. Froude married in 1839 and had five children, one of whom, Robert Edmund Froude (1846–1924), was to succeed him in later years in his research work for the Admiralty. Following the death of his father, Froude moved to Paignton, and there commenced his studies on the resistance of solid bodies moving through fluids. Initially these were with hulls towed through a house roof storage tank by wires taken over a pulley and attached to falling weights, but the work became more sophisticated and was conducted on ponds and the open water of a creek near Dartmouth. Froude published work on the rolling of ships in the second volume of the Transactions of the then new Institution of Naval Architects and through this became acquainted with Sir Edward Reed. This led in 1870 to the Admiralty's offer of £2,000 towards the cost of an experimental tank for ship models at Torquay. The tank was completed in 1872 and tests were carried out on the model of HMS Greyhound following full-scale towing trials which had commenced on the actual ship the previous year. From this Froude enunciated his Law of Comparisons, which defines the rules concerning the relationship of the power required to move geometrically similar floating bodies across fluids. It enabled naval architects to predict, from a study of a much less expensive and smaller model, the resistance to motion and the power required to move a full-size ship. The work in the tank led Froude to design a model-cutting machine, dynamometers and machinery for the accurate ruling of graph paper. Froude's work, and later that of his son, was prodigious and covered many fields of ship design, including powering, propulsion, rolling, steering and stability. In only six years he had stamped his academic authority on the new science of hydrodynamics, served on many national committees and corresponded with fellow researchers throughout the world. His health suffered and he sailed for South Africa to recuperate, but he contracted dysentery and died at Simonstown. He will be remembered for all time as one of the greatest "fathers" of naval architecture.

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SUBJECT AREA: Canals

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Thomas Gilpin belonged to a wealthy Quaker family descended from Joseph Gilpin, who had emigrated from England in 1696. He received little formal education and was mainly self-educated in mathematics, surveying and science, in which subjects he was particularly interested. With estates in Delaware and Maryland, he was involved in farming and manufacturing. He moved to Philadelphia in 1769, which further extended his activities. With his fortune he was able to indulge his interest in science, and he was one of the original members of the American Philosophical Society in 1769. He wrote papers on the wheat fly, the seventeen-year locust and the migration of herrings. It was through this Society that he became friendly with Benjamin Franklin, to whom he wrote on 10 October 1769 setting out his proposals for and advocacy of a canal linking the Elk River on Chesapeake Bay with the Delaware River and Bay, thereby cutting off a long haul of several hundred miles for vessels around Cape Charles with a dangerous passage unto the Atlantic Ocean. Gilpin also invented a hydraulic pump that delighted Franklin very much. Gilpin had visited England in 1768 during the formation of his ideas for the Chesapeake \& Delaware Canal, and probably visited the Bridgewater Canal while there. Despite his pressing advocacy the canal had to wait until after his death, but later his son Joshua, a director from 1803 to 1824, saw the canal through many difficulties although he had resigned before the official opening in 1829. At the outbreak of the American War of Independence, in 1777, Gilpin, together with other Quakers, was arrested in Philadelphia owing to suspicions of his loyalty on the grounds that as a Quaker he refused to sign the Oath of Allegiance. He was later exiled to Winchester, Virginia, where he died in April 1778.

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SUBJECT AREA: Land transport, Railways and locomotives

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Gregory's father was Professor of Mathematics at the Royal Military Academy, Woolwich.C.H. Gregory himself, after working for Robert Stephenson, was appointed Engineer to the London \& Croydon Railway in 1839. On it, at New Cross in 1841, he installed a semaphore signal derived from signalling apparatus used by the Royal Navy; two hinged semaphore arms projected either side from the top of a post, signalling to drivers of trains in each direction of travel. In horizontal position each arm signified "danger", an arm inclined at 45° meant "caution" and the vertical position, in which the arms disappeared within a slot in the post, meant "all right". Gregory's signal was the forerunner of semaphore signals adopted on railways worldwide. In 1843 Gregory invented the stirrup frame: signal arms were connected to stirrups that were pushed down by the signalman's foot in order to operate them, while the points were operated by levers. The stirrups were connected together to prevent conflicting signals from being shown. This was a predecessor of interlocking. In 1846 Gregory became Engineer to the Bristol \& Exeter Railway, where in 1848 he co-operated with W.B. Adams in the development and operation of the first self-propelled railcar. He later did civil engineering work in Italy and France, was Engineer to the Somerset Central and Dorset Central railways and became Consulting Engineer for the government railways in Ceylon (now Sri Lanka), Cape of Good Hope, Straits Settlements and Trinidad.

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SUBJECT AREA: Horology

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Born Edmund Beckett Denison, he was educated at Eton and Trinity College, Cambridge, where he studied mathematics, graduating in 1838. He was called to the Bar in 1841 and became a Queen's Counsel in 1854. He built up a large and lucrative practice which gave him the independence to pursue his many interests outside law. His interest in horology may have been stimulated by a friend and fellow lawyer, J.M. Bloxham, who interestingly had invented a gravity escapement with an affinity to the escapement eventually used by Denison. Denison studied horology with his usual thoroughness and by 1850 he had published his Rudimentary Treatise on Clock and Watchmaking. It was natural, therefore, that he should have been invited to be a referee when a disagreement arose over the design of the clock for the new Houses of Parliament. Typically, he interpreted his brief very liberally and designed the clock himself. The most distinctive feature of the clock, in its final form, was the incorporation of a gravity escapement. A gravity escapement was particularly desirable in a public clock as it enabled the pendulum to receive a constant impulse (and thus swing with a constant amplitude), despite the variable forces that might be exerted by the wind on the exposed hands. The excellent performance of the prestigious clock at Westminster made Denison's form of gravity escapement de rigueur for large mechanical public clocks produced in Britain and in many other countries. In 1874 he inherited his father's baronetcy, dropping the Denison name, but later adopted the name Grimthorpe when he was created a Baron in 1886.

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SUBJECT AREA: Electricity, Mechanical, pneumatic and hydraulic engineering

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Guericke was born into a patrician family in Magdeburg. He was educated at the University of Leipzig in 1617–20 and at the University of Helmstedt in 1620. He then spent two years studying law at Jena, and in 1622 went to Leiden to study law, mathematics, engineering and especially fortification. He spent most of his life in politics, for he was elected an alderman of Magdeburg in 1626. After the destruction of Magdeburg in 1631, he worked in Brunswick and Erfurt as an engineer for the Swedish government, and then in 1635 for the Electorate of Saxony. He was Mayor of Magdeburg for thirty years, between 1646 and 1676. He was ennobled in 1666 and retired from public office in 168land went to Hamburg. It was through his attendances at international congresses and at princely courts that he took part in the exchange of scientific ideas.

From his student days he was concerned with the definition of space and posed three questions: can empty space exist or is space always filled? How can heavenly bodies affect each other across space and how are they moved? Is space, and so also the heavenly bodies, bounded or unbounded? In c. 1647 Guericke made a suction pump for air and tried to exhaust a beer barrel, but he could not stop the leaks. He then tried a copper sphere, which imploded. He developed a series of spectacular demonstrations with his air pump. In 1654 at Rattisbon he used a vertical cylinder with a well-fitting piston connected over pulleys by a rope to fifty men, who could not stop the piston descending when the cylinder was exhausted. More famous were his copper hemispheres which, when exhausted, could not be drawn apart by two teams of eight horses. They were first demonstrated at Magdeburg in 1657 and at the court in Berlin in 1663. Through these experiments he discovered the elasticity of air and began to investigate its density at different heights. He heard of the work of Torricelli in 1653 and by 1660 had succeeded in making barometric forecasts. He published his famous work New Experiments Concerning Empty Space in 1672. Between 1660 and 1663 Guericke constructed a large ball of sulphur that could be rotated on a spindle. He found that, when he pressed his hand on it and it was rotated, it became strongly electrified; he thus unintentionally became the inventor of the first machine to generate static electricity. He attempted to reach a complete physical explanation of the world and the heavens with magnetism as a primary force and evolved an explanation for the rotation of the heavenly bodies.

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SUBJECT AREA: Photography, film and optics

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Born of French parents, Lippman's work began with a distinguished career in classics, philosophy, mathematics and physics at the Ecole Normale in Luxembourg. After further studies in physics at Heidelberg University, he returned to France and the Sorbonne, where he was in 1886 appointed Director of Physics. He was a leading pioneer in France of research into electricity, optics, heat and other branches of physics.

In 1886 he conceived the idea of recording the existence of standing waves in light when it is reflected back on itself, by photographing the colours so produced. This required the production of a photographic emulsion that was effectively grainless: the individual silver halide crystals had to be smaller than the shortest wavelength of light to be recorded. Lippman succeeded in this and in 1891 demonstrated his process. A glass plate was coated with a grainless emulsion and held in a special plate-holder, glass towards the lens. The back of the holder was filled with mercury, which provided a perfect reflector when in contact with the emulsion. The standing waves produced during the exposure formed laminae in the emulsion, with the number of laminae being determined by the wavelength of the incoming light at each point on the image. When the processed plate was viewed under the correct lighting conditions, a theoretically exact reproduction of the colours of the original subject could be seen. However, the Lippman process remained a beautiful scientific demonstration only, since the ultra-fine-grain emulsion was very slow, requiring exposure times of over 10,000 times that of conventional negative material. Any method of increasing the speed of the emulsion also increased the grain size and destroyed the conditions required for the process to work.

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SUBJECT AREA: Electronics and information technology, Telecommunications

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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.

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See also: Hertz, Heinrich Rudolph

SUBJECT AREA: Aerospace

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The son of a physician, Oberth originally studied medicine in Munich, but his education was interrupted by the First World War and service in the Austro-Hungarian Army. Wounded, he passed the time by studying astronautics. He apparently simulated weightlessness and worked out the design for a long-range liquid-propelled rocket, but his ideas were rejected by the War Office; after the war he submitted them as a dissertation for a PhD at Heidelberg University, but this was also rejected. Consequently, in 1923, whilst still an unknown mathematics teacher, he published his ideas at his own expense in the book The Rocket into Interplanetary Space. These included a description of how rockets could achieve a sufficient velocity to escape the gravitational field of the earth. As a result he gained international prestige almost overnight and learned of the work of Robert Goddard and Konstantin Tsiolkovsky. After correspondence with the Goddard and Tsiolkovsky, Oberth published a further work in 1929, The Road to Space Travel, in which he acknowledged the priority of Goddard's and Tsiolkovski's calculations relating to space travel; he went on to anticipate by more than thirty years the development of electric and ionic propulsion and to propose the use of giant mirrors to control the weather. For this he was awarded the annual Hirsch Prize of 10,000 francs. From 1925 to 1938 he taught at a college in Mediasch, Transylvania, where he carried out experiments with petroleum and liquid-air rockets. He then obtained a lecturing post at Vienna Technical University, moving two years later to Dresden University and becoming a German citizen. In 1941 he became assistant to the German rocket engineer Werner von Braun at the rocket development centre at Peenemünde, and in 1943 he began work on solid propellants. After the Second World War he spent a year in Switzerland as a consultant, then in 1950 he moved to Italy to develop solid-propellant anti-aircraft rockets for the Italian Navy. Five years later he moved to the USA to carry out advanced rocket research for the US Army at Huntsville, Alabama, and in 1958 he retired to Feucht, near Nuremberg, Germany, where he wrote his autobiography.

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KF / IMcN