acting+appointment

SUBJECT AREA: Electricity, Electronics and information technology, Public utilities

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After attending Owens College, Manchester, Hopkinson was admitted to Trinity College, Cambridge, in 1867 to read for the Mathematical Tripos. An appointment in 1872 with the lighthouse department of the Chance Optical Works in Birmingham directed his attention to electrical engineering. His most noteworthy contribution to lighthouse engineering was an optical system to produce flashing lights that distinguished between individual beacons. His extensive researches on the dielectric properties of glass were recognized when he was elected to a Fellowship of the Royal Society at the age of 29. Moving to London in 1877 he became established as a consulting engineer at a time when electricity supply was about to begin on a commercial scale. During the remainder of his life, Hopkinson's researches resulted in fundamental contributions to electrical engineering practice, dynamo design and alternating current machine theory. In making a critical study of the Edison dynamo he developed the principle of the magnetic circuit, a concept also arrived at by Gisbert Kapp around the same time. Hopkinson's improvement of the Edison dynamo by reducing the length of the field magnets almost doubled its output. In 1890, in addition to-his consulting practice, Hopkinson accepted a post as the first Professor of Electrical Engineering and Head of the Siemens laboratory recently established at King's College, London. Although he was not involved in lecturing, the position gave him the necessary facilities and staff and student assistance to continue his researches. Hopkinson was consulted on many proposals for electric traction and electricity supply, including schemes in London, Manchester, Liverpool and Leeds. He also advised Mather and Platt when they were acting as contractors for the locomotives and generating plant for the City and South London tube railway. As early as 1882 he considered that an ideal method of charging for the supply of electricity should be based on a two-part tariff, with a charge related to maximum demand together with a charge for energy supplied. Hopkinson was one the foremost expert witnesses of his day in patent actions and was himself the patentee of over forty inventions, of which the three-wire system of distribution and the series-parallel connection of traction motors were his most successful. Jointly with his brother Edward, John Hopkinson communicated the outcome of his investigations to the Royal Society in a paper entitled "Dynamo Electric Machinery" in 1886. In this he also described the later widely used "back to back" test for determining the characteristics of two identical machines. His interest in electrical machines led him to more fundamental research on magnetic materials, including the phenomenon of recalescence and the disappearance of magnetism at a well-defined temperature. For his work on the magnetic properties of iron, in 1890 he was awarded the Royal Society Royal Medal. He was a member of the Alpine Club and a pioneer of rock climbing in Britain; he died, together with three of his children, in a climbing accident.

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SUBJECT AREA: Electronics and information technology, Public utilities, Telecommunications

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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.

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GW / KF

SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering

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Rankine was educated at Ayr Academy and Glasgow High School, although he appears to have learned much of his basic mathematics and physics through private study. He attended Edinburgh University and then assisted his father, who was acting as Superintendent of the Edinburgh and Dalkeith Railway. This introduction to engineering practice was followed in 1838 by his appointment as a pupil to Sir John MacNeill, and for the next four years he served under MacNeill on his Irish railway projects. While still in his early twenties, Rankine presented pioneering papers on metal fatigue and other subjects to the Institution of Civil Engineers, for which he won a prize, but he appears to have resigned from the Civils in 1857 after an argument because the Institution would not transfer his Associate Membership into full Membership. From 1844 to 1848 Rankine worked on various projects for the Caledonian Railway Company, but his interests were becoming increasingly theoretical and a series of distinguished papers for learned societies established his reputation as a leading scholar in the new science of thermodynamics. He was elected Fellow of the Royal Society in 1853. At the same time, he remained intimately involved with practical questions of applied science, in shipbuilding, marine engineering and electric telegraphy, becoming associated with the influential coterie of fellow Scots such as the Thomson brothers, Napier, Elder, and Lewis Gordon. Gordon was then the head of a large and successful engineering practice, but he was also Regius Professor of Engineering at the University of Glasgow, and when he retired from the Chair to pursue his business interests, Rankine, who had become his Assistant, was appointed in his place.

From 1855 until his premature death in 1872, Rankine built up an impressive engineering department, providing a firm theoretical basis with a series of text books that he wrote himself and most of which remained in print for many decades. Despite his quarrel with the Institution of Civil Engineers, Rankine took a keen interest in the institutional development of the engineering profession, becoming the first President of the Institution of Engineers and Shipbuilders in Scotland, which he helped to establish in 1857. Rankine campaigned vigorously for the recognition of engineering studies as a full university degree at Glasgow, and he achieved this in 1872, the year of his death. Rankine was one of the handful of mid-nineteenth century engineers who virtually created engineering as an academic discipline.

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