Electricity

See also: INDEX BY SUBJECT AREA

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Alexanderson, Ernst Frederik Werner

Ampère, André-Marie

Aspinall, Sir John Audley Frederick

Ayrton, William Edward

Bardeen, John

Braun, Karl Ferdinand

Brown, Charles Eugene Lancelot

Brush, Charles Francis

Cady, Walter Guyton

Cardew, Philip

Coolidge, William David

Crompton, Rookes Evelyn Bell

Crookes, Sir William

Cruickshank, William

Daft, Leo

Dalen, Nils Gustav

Daniell, John Frederick

Davenport, Thomas

Davidson, Robert

Donkin, Bryan IV

Duddell, William du Bois

Edison, Thomas Alva

Faraday, Michael

Faure, Camille Alphonse

Ferranti, Sebastian Ziani de

Gramme, Zénobe Théophile

Grove, Sir William Robert

Guericke, Otto von

Halske, Johann Georg

Hammond, Robert

Henry, Joseph

Hertz, Heinrich Rudolph

Hjorth, Soren

Holmes, Frederic Hale

Hopkinson, John

Ilgner, Karl

Jablochkoff, Paul

Jacobi, Moritz Hermann von

Joubert, Jules François

Kaplan, Viktor

Kapp, Gisbert Johann Eduard Karl

Kennelly, Arthur Edwin

Kettering, Charles Franklin

Laithwaite, Eric Roberts

Langmuir, Irving

Laval, Carl Gustaf Patrik de

Leclanché, Georges

Lovelock, James Ephraim

Mavor, Henry Alexander

Maxwell, James Clerk

Meritens, Baron Auguste de

Merz, Charles Hesterman

Morrison, William Murray

Ohm, Georg Simon

Page, Charles Grafton

Parsons, Sir Charles Algernon

Paul, Robert William

Pixii, Antoine Hippolyte

Planté, Raimond Louis Gaston

Rawcliffe, Gordon Hindle

Salomans, Sir David Lionel

Siemens, Sir Charles William

Siemens, Dr Ernst Werner von

Smith, Willoughby

Sperry, Elmer Ambrose

Sprague, Frank Julian

Staite, William Edwards

Stratingh, Sibrandus

Sturgeon, William

Swan, Sir Joseph Wilson

Tesla, Nikola

Thévénin, Léon Charles

Thomson, Elihu

Thomson, Sir William

Unwin, William Cawthorne

Volk, Magnus

Volta, Alessandro Giuseppe Antonio Anastasio

Weber, Wilhelm Eduard

Westinghouse, George

Weston, Edward

Wilde, Henry

Woods, Granville

Woolrich, John Stephen

Wright, Arthur

SUBJECT AREA: Electricity, Public utilities

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Merz was educated at Bootham School in York and Armstrong College in Newcastle. He served an apprenticeship with the Newcastle Electric Supply Company at their first power station, Pandon Dene, and part of his training was at Robey and Company of Lincoln, steam engine builders, and the British Thomson-Houston Company, electrical equipment manufacturers. After working at Bankside in London and at Croydon, he became Manager of the Croydon supply undertaking. In 1898 he went to Cork on behalf of BTH to build and manage a tramway and electricity company. It was there that he met William McLellan, who later joined him in establishing a firm of consulting engineers. Merz, with his vision of large-scale electricity supply, pioneered an integrated traction and electricity scheme in north-eastern England. He was involved in the reorganization of electricity schemes in many countries and established a reputation as a leading parliamentary witness. Merz was appointed Director of Experiments and Research at the Admiralty, where his main contribution was the creation of an organization of outstanding engineers and scientists during the First World War. In 1925 he was largely responsible for a report of the Weir Committee which led to the Electricity (Supply) Act of 1926, the formation of the Central Electricity Board and the construction of the National Grid. The choice of 132 kV as the original grid voltage was that of Merz and his associates, as was the origin of the term "grid". Merz and his firm produced many technical innovations, including the first power-system control room and Merz-Price and Merz-Hunter forms of cable and transformer protection.

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SUBJECT AREA: Horology, Telecommunications

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Alexander Bain was born into a crofting family in a remote part of Scotland. He was apprenticed to a watchmaker in Wick and during that time he was strongly influenced by a lecture on "Heat, sound and electricity" that he heard in nearby Thurso. This lecture induced him to take up a position in Clerkenwell in London, working as a journeyman clockmaker, where he was able to further his knowledge of electricity by attending lectures at the Adelaide Gallery and the Polytechnic Institution. His thoughts naturally turned to the application of electricity to clockmaking, and despite a bitter dispute with Charles Wheatstone over priority he was granted the first British patent for an electric clock. This patent, taken out on 11 January 1841, described a mechanism for an electric clock, in which an oscillating component of the clock operated a mechanical switch that initiated an electromagnetic pulse to maintain the regular, periodic motion. This principle was used in his master clock, produced in 1845. On 12 December of the same year, he patented a means of using electricity to control the operation of steam railway engines via a steam-valve. His earliest patent was particularly far-sighted and anticipated most of the developments in electrical horology that occurred during the nineteenth century. He proposed the use of electricity not only to drive clocks but also to distribute time over a distance by correcting the hands of mechanical clocks, synchronizing pendulums and using slave dials (here he was anticipated by Steinheil). However, he was less successful in putting these ideas into practice, and his electric clocks proved to be unreliable. Early electric clocks had two weaknesses: the battery; and the switching mechanism that fed the current to the electromagnets. Bain's earth battery, patented in 1843, overcame the first defect by providing a reasonably constant current to drive his clocks, but unlike Hipp he failed to produce a reliable switch.

The application of Bain's numerous patents for electric telegraphy was more successful, and he derived most of his income from these. They included a patent of 12 December 1843 for a form of fax machine, a chemical telegraph that could be used for the transmission of text and of images (facsimile). At the receiver, signals were passed through a moving band of paper impregnated with a solution of ammonium nitrate and potassium ferrocyanide. For text, Morse code signals were used, and because the system could respond to signals faster than those generated by hand, perforated paper tape was used to transmit the messages; in a trial between Paris and Lille, 282 words were transmitted in less than one minute. In 1865 the Abbé Caselli, a French engineer, introduced a commercial fax service between Paris and Lyons, based on Bain's device. Bain also used the idea of perforated tape to operate musical wind instruments automatically. Bain squandered a great deal of money on litigation, initially with Wheatstone and then with Morse in the USA. Although his inventions were acknowledged, Bain appears to have received no honours, but when towards the end of his life he fell upon hard times, influential persons in 1873 secured for him a Civil List Pension of £80 per annum and the Royal Society gave him £150.

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See also: Bakewell, Frederick C.

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SUBJECT AREA: Electricity, Public utilities

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Ferranti, who had taken an interest in electrical and mechanical devices from an early age, was educated at St Augustine's College in Ramsgate and for a short time attended evening classes at University College, London. Rather than pursue an academic career, Ferranti, who had intense practical interests, found employment in 1881 with the Siemens Company (see Werner von Siemens) in their experimental department. There he had the opportunity to superintend the installation of electric-lighting plants in various parts of the country. Becoming acquainted with Alfred Thomson, an engineer, Ferranti entered into a short-lived partnership with him to manufacture the Ferranti alternator. This generator, with a unique zig-zag armature, had an efficiency exceeding that of all its rivals. Finding that Sir William Thomson had invented a similar machine, Ferranti formed a company with him to combine the inventions and produce the Ferranti- Thomson machine. For this the Hammond Electric Light and Power Company obtained the sole selling rights.

In 1885 the Grosvenor Gallery Electricity Supply Corporation was having serious problems with its Gaulard and Gibbs series distribution system. Ferranti, when consulted, reviewed the design and recommended transformers connected across constant-potential mains. In the following year, at the age of 22, he was appointed Engineer to the company and introduced the pattern of electricity supply that was eventually adopted universally. Ambitious plans by Ferranti for London envisaged the location of a generating station of unprecedented size at Deptford, about eight miles (13 km) from the city, a departure from the previous practice of placing stations within the area to be supplied. For this venture the London Electricity Supply Corporation was formed. Ferranti's bold decision to bring the supply from Deptford at the hitherto unheard-of pressure of 10,000 volts required him to design suitable cables, transformers and generators. Ferranti planned generators with 10,000 hp (7,460 kW)engines, but these were abandoned at an advanced stage of construction. Financial difficulties were caused in part when a Board of Trade enquiry in 1889 reduced the area that the company was able to supply. In spite of this adverse situation the enterprise continued on a reduced scale. Leaving the London Electricity Supply Corporation in 1892, Ferranti again started his own business, manufacturing electrical plant. He conceived the use of wax-impregnated paper-insulated cables for high voltages, which formed a landmark in the history of cable development. This method of flexible-cable manufacture was used almost exclusively until synthetic materials became available. In 1892 Ferranti obtained a patent which set out the advantages to be gained by adopting sector-shaped conductors in multi-core cables. This was to be fundamental to the future design and development of such cables.

A total of 176 patents were taken out by S.Z. de Ferranti. His varied and numerous inventions included a successful mercury-motor energy meter and improvements to textile-yarn produc-tion. A transmission-line phenomenon where the open-circuit voltage at the receiving end of a long line is greater than the sending voltage was named the Ferranti Effect after him.

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SUBJECT AREA: Electricity, Public utilities

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After an education at Nunhead Grammar School, Hammond founded engineering businesses in Middlesbrough and London. Obtaining the first concession from the Anglo- American Brush Company for the exploitation of their system in Britain, he was instrumental in popularizing the Brush arc-lighting generator. Schemes using this system, which he established at Chesterfield, Brighton, Eastbourne and Hastings in 1881–2, were the earliest public electricity-supply ventures in Britain. On the invention of the incandescent lamp, high-voltage Brush dynamos were employed to operate both arc and incandescent lamps. The limitations of this arrangement led Hammond to become the sole agent for the Ferranti alternator, introduced in 1882. Commencing practice as a consulting engineer, Hammond was responsible for the construction of many electricity works in the United Kingdom, of which the most notable were those at Leeds, Hackney (London) and Dublin, in addition to many abroad. Appreciating the need for trained engineers for the new electrical industry and profession then being created, in 1882 he established the Hammond Electrical Engineering College. Later, in association with Francis Ince, he founded Faraday House, a training school that pioneered the concept of "sandwich courses" for engineers. Between 1883 and 1903 he paid several visits to the United States to study developments in electric traction and was one of the advisers to the Postmaster General on the acquisition of the telephone companies.

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SUBJECT AREA: Electricity, Ports and shipping, Public utilities

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Mavor came from a distinguished Scottish family with connections in medicine, industry and the arts. On completion of his education at Glasgow University, he joined R.J.Crompton \& Co.; then in 1883, along with William C.Muir, he established the Glasgow firm which later became well known as Mavor and Coulson. It pioneered the supply of electricity to public undertakings and equipped the first two generating stations in Scotland. Mavor and his fellow directors appreciated the potential demand by industry in Glasgow for electricity. Two industries were especially well served; first, the coal-mines, where electric lighting and power transformed efficiency and safety beyond recognition; and second, marine engineering. Here Mavor recognized the importance of the variable-speed motor in working with marine propellers which have a tighter range of efficient working speeds. In 1911 he built a 50 ft (15 m) motor launch, appropriately named Electric Arc, at Dumbarton and fitted it with an alternating-current motor driven by a petrol engine and dynamo. Within two years British shipyards were building electrically powered ships, and by the beginning of the First World War the United States Navy had a 20,000-ton collier with this new form of propulsion.

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SUBJECT AREA: Automotive engineering, Domestic appliances and interiors, Electricity, Land transport

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Salomans inherited his baronetcy from his uncle, Sir David Salomans (1797–1873), who had been Member of Parliament for Greenwich and the first Jewish Lord Mayor of London. He was the archetypal amateur engineer and inventor of the Victorian age, indulging in such interests as photography, motoring, electricity, woodworking, polariscopy and astronomy. His house, "Broomhill", near Tun bridge Wells in Kent, was one of the first to be lit by electricity and is said to have been the first to use electricity for cooking. He acted as architect for the building of the stables, the water tower and the 150-seat theatre at his home. In 1874 he was granted a patent for an automatic railway signalling system. He was the founder in 1895 of the first motoring organization in Great Britain, the Self Propelled Traffic Association, forerunner of the Royal Automobile Club (RAC). He was also the organizer of the first motor show to be held in Britain, on 15 October 1895. It is said that, in spite of being the Mayor of Tunbridge Wells, Salomans defied the law and drove without the obligatory pedestrian with a red flag preceding his vehicle; this requirement was removed with the later Light (Road) Locomotives Act, which raised the speed limit to 12 mph (19 km/h).

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SUBJECT AREA: Electricity

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After leaving an apprenticeship as a shoemaker, Sturgeon enlisted in the militia. Self-educated during service as a private in the Royal Artillery, he began to construct scientific apparatus. When he left the army in 1820 Sturgeon became an industrious writer, contributing papers to the Philosophical Magazine. In 1823 he was appointed Lecturer in Natural Science at the East India Company's Military College in Addiscombe. His invention in 1823 of an electromagnet with a horseshoe-shaped, soft iron core provided a much more concentrated magnetic field than previously obtained. An electric motor he designed in 1832 embodied his invention of the first metallic commutator. This was used to rotate a meat-roasting jack. Over an extended period he conducted researches into atmospheric electricity and also introduced the practice of amalgamating zinc in primary cells to prevent local action.

Sturgeon became Lecturer at the Adelaide Gallery, London, in 1832, an appointment of short duration, terminating when the gallery closed. In 1836 he established a monthly publication, The Annals of Electricity, Magnetism and Chemistry; and Guardian of Experimental Science, the first journal in England to be devoted to the subject. It was to this journal that James Prescot Joule contributed the results of his own researches in electromagnetism. Due to lack of financial support the publication ceased in 1843 after ten volumes had been issued. At the age of 57 Sturgeon became Superintendent of the Victoria Gallery of Practical Science in Manchester; after this gallery closed, the last five years of his life were spent in considerable poverty.

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SUBJECT AREA: Electricity

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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.

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SUBJECT AREA: Electricity, Electronics and information technology, Horology, Telecommunications

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After obtaining BSc and MSc degrees in physics at Brown University in 1896 and 1897, respectively, Cady went to Berlin, obtaining his PhD in 1900. Returning to the USA he initially worked for the US Coast and Geodetic Survey, but in 1902 he took up a post at the Wesleyan University, Connecticut, remaining as Professor of Physics from 1907 until his retirement in 1946. During the First World War he became interested in piezo-electricity as a result of attending a meeting on techniques for detecting submarines, and after the war he continued to work on the use of piezo-electricity as a transducer for generating sonar beams. In the process he discovered that piezo-electric materials, such as quartz, exhibited high-stability electrical resonance, and in 1921 he produced the first working piezo-electric resonator. This idea was subsequently taken up by George Washington Pierce and others, resulting in very stable oscillators and narrow-band filters that are widely used in the 1990s in radio communications, electronic clocks and watches.

Internationally known for his work, Cady retired from his professorship in 1946, but he continued to work for the US Navy. From 1951 to 1955 he was a consultant and research associate at the California Institute of Technology, after which he returned to Providence to continue research at Brown, filing his last patent (one of over fifty) at the age of 93 years.

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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: Electricity

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After studying architecture at Göttingen University, Jacobi turned his attention to physics and chemistry. In 1835 he was appointed a professor of civil engineering at the University of Dorpat (which later assumed the Estonian name of Tartu). Later, moving to St Petersburg, he became a member of the Imperial Academy of Sciences and commenced research on electricity and its practical applications. In December 1834 Jacobi presented a paper to the Academy of Sciences in Paris in which he stated that he had obtained rotation by electromagnetic methods in May of that year. Tsar Nicholas of Russia gave him a grant to prove that his electric motor had a practical application. Jacobi had a boat constructed that measured 28 ft in length and was propelled by paddles connected to an electric motor of his own design. Powered by Grove cells, it carried about fourteen passengers at a speed of almost 3 mph (5 km/h) on the River Neva. The weight of and possibly the fumes from the batteries contributed to the abandonment of the project. In 1839 Jacobi introduced electrotyping, i.e. the reproduction of forms by electrodeposition, which was one of the first commercial applications of electricity. In 1840 he reported the results of his investigations into the power of the electromagnet as a function of various parameters to the British Association.

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SUBJECT AREA: Electricity, Land transport, Public utilities, Railways and locomotives

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George Westinghouse's father was an ingenious manufacturer of agricultural implements; the son, after a spell in the Union Army during the Civil War, and subsequently in the Navy as an engineer, went to work for his father. He invented a rotary steam engine, which proved impracticable; a rerailing device for railway rolling stock in 1865; and a cast-steel frog for railway points, with longer life than the cast-iron frogs then used, in 1868–9. During the same period Westinghouse, like many other inventors, was considering how best to meet the evident need for a continuous brake for trains, i.e. one by which the driver could apply the brakes on all vehicles in a train simultaneously instead of relying on brakesmen on individual vehicles. By chance he encountered a magazine article about the construction of the Mont Cenis Tunnel, with a description of the pneumatic tools invented for it, and from this it occurred to him that compressed air might be used to operate the brakes along a train.

The first prototype was ready in 1869 and the Westinghouse Air Brake Company was set up to manufacture it. However, despite impressive demonstration of the brake's powers when it saved the test train from otherwise certain collision with a horse-drawn dray on a level crossing, railways were at first slow to adopt it. Then in 1872 Westinghouse added to it the triple valve, which enabled the train pipe to charge reservoirs beneath each vehicle, from which the compressed air would apply the brakes when pressure in the train pipe was reduced. This meant that the brake was now automatic: if a train became divided, the brakes on both parts would be applied. From then on, more and more American railways adopted the Westinghouse brake and the Railroad Safety Appliance Act of 1893 made air brakes compulsory in the USA. Air brakes were also adopted in most other parts of the world, although only a minority of British railway companies took them up, the remainder, with insular reluctance, preferring the less effective vacuum brake.

From 1880 Westinghouse was purchasing patents relating to means of interlocking railway signals and points; he combined them with his own inventions to produce a complete signalling system. The first really practical power signalling scheme, installed in the USA by Westinghouse in 1884, was operated pneumatically, but the development of railway signalling required an awareness of the powers of electricity, and it was probably this that first led Westinghouse to become interested in electrical processes and inventions. The Westinghouse Electric Company was formed in 1886: it pioneered the use of electricity distribution systems using high-voltage single-phase alternating current, which it developed from European practice. Initially this was violently opposed by established operators of direct-current distribution systems, but eventually the use of alternating current became widespread.

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SUBJECT AREA: Electricity, Public utilities

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Arthur Wright, educated at Maryborough College, attended a course of training at the School of Submarine Telegraphy, Telephony and Electric Light in London. In 1882 he joined the Hammond Company in Brighton, the first company to afford a regular electricity supply in Britain on a commercial basis for street and private lighting. He invented a recording ammeter and also a thermal-demand indicator used in conjunction with a tariff based on maximum demand in addition to energy consumption. This indicator was to remain in use for almost half a century.

Resigning his position in Brighton in 1889, he joined the staff of S.Z.de Ferranti and served with him during developments at the Grosvenor Gallery and Deptford stations in London. In 1891 he returned to Brighton as its first Borough Electrical Engineer. From 1900 onwards he had an extensive consulting practice designing early power stations, and was approached by many municipalities and companies in Britain, the United States, South America and Australia, primarily on finance and tariffs. Associated with the founding of the Municipal Electrical Association in 1905, the following year he became its first President.

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SUBJECT AREA: Electricity, Land transport, Public utilities, Railways and locomotives

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After education at the Royal Military Academy in Woolwich, Cardew was placed in charge of Bermudan military telegraphs in 1876. In 1889 he was appointed the first Electrical Adviser to the Board of Trade, where he formulated valuable regulations for the safety and control of public electricity supplies. In 1883 Cardew invented the thermogalvanometer, a hot-wire measuring instrument, that became widely used as a voltmeter but was obsolete by 1907. The device depended for its action on the heating and subsequent elongation of a platinum wire and could be used on alternating currents of high frequency. Retiring from the Board of Trade in 1899, Cardew joined a partnership of consulting engineers with Sir William Preece and his son. Taking a particular interest in railway electrification, he became a director of the London Brighton \& South Coast Railway.

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SUBJECT AREA: Electricity, Land transport, Public utilities, Railways and locomotives

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Leo Daft, son of a British civil engineer, studied electricity and emigrated to the USA in 1866. After various occupations including running a photographic studio, he joined in 1879 the New York Electric Light Company, which was soon merged into the Daft Electric Company. This company developed electrically powered machinery and built electric-power plants. In 1883 Daft built an electric locomotive called Ampere for the Saratoga \& Mount McGregor Railroad. This is said to have been the first electric main-line locomotive for standard gauge. It collected current from a central rail, had an output of 12 hp (9 kW) and hauled 10 tons at speeds up to 9 mph (14.5 km/h). Two years later Daft made a much improved locomotive for the New York Elevated Railway, the Benjamin Franklin, which drew current at 250 volts from a central rail and had two 48 in. (122 cm)-diameter driving wheels and two 33 in. (84 cm)-diameter trailing wheels. Re-equipped in 1888 with four driving wheels and a 125 hp (93 kW) motor, this could haul an eight-car train at 10 mph (16 km/h). Meanwhile, in 1884, Daft's company had manufactured all the electrical apparatus for the Massachusetts Electric Power Company, the first instance of a complete central station to generate and distribute electricity for power on a commercial scale. In 1885 it electrified a branch of the Baltimore Union Passenger Railway, the first electrically operated railway in the USA. Subsequently Daft invented a process for vulcanizing rubber onto metal that came into general use. He never became an American citizen.

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See also: Siemens, Dr Ernst Werner von

SUBJECT AREA: Electricity

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When he was 14 years old Davenport was apprenticed to a blacksmith for seven years. At the close of his apprenticeship in 1823 he opened a blacksmith's shop in Brandon, Vermont. He began experimenting with electromagnets after observing one in use at the Penfield Iron Works at Crown Point, New York, in 1831. He saw the device as a possible source of power and by July 1834 had constructed his first electric motor. Having totally abandoned his regular business, Davenport built and exhibited a number of miniature machines; he utilized an electric motor to propel a model car around a circular track in 1836, and this became the first recorded instance of an electric railway. An application for a patent and a model were destroyed in a fire at the United States Patent Office in December 1836, but a second application was made and Davenport received a patent the following year for Improvements in Propelling Machinery by Magnetism and Electromagnetism. A British patent was also obtained. A workshop and laboratory were established in New York, but Davenport had little financial backing for his experiments. He built a total of over one hundred motors but was defeated by the inability to obtain an inexpensive source of power. Using an electric motor of his own design to operate a printing press in 1840, he undertook the publication of a journal, The Electromagnet and Mechanics' Intelligencer. This was the first American periodical on electricity, but it was discontinued after a few issues. In failing health he retired to Vermont where in the last year of his life he continued experiments in electromagnetism.

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SUBJECT AREA: Electricity

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Faraday's father was a blacksmith recently moved south from Westmorland. The young Faraday's formal education was limited to attendance at "a Common Day School", and then he worked as an errand boy for George Riebau, a bookseller and bookbinder in London's West End. Riebau subsequently took him as an apprentice bookbinder, and Faraday seized every opportunity to read the books that came his way, especially scientific works.

A customer in the shop gave Faraday tickets to hear Sir Humphry Davy lecturing at the Royal Institution. He made notes of the lectures, bound them and sent them to Davy, asking for scientific employment. When a vacancy arose for a laboratory assistant at the Royal Institution, Davy remembered Faraday, who he took as his assistant on an 18- month tour of France, Italy and Switzerland (despite the fact that Britain and France were at war!). The tour, and especially Davy's constant company and readiness to explain matters, was a scientific education for Faraday, who returned to the Royal Institution as a competent chemist in his own right. Faraday was interested in electricity, which was then viewed as a branch of chemistry. After Oersted's announcement in 1820 that an electric current could affect a magnet, Faraday devised an arrangement in 1821 for producing continuous motion from an electric current and a magnet. This was the basis of the electric motor. Ten years later, after much thought and experiment, he achieved the converse of Oersted's effect, the production of an electric current from a magnet. This was magneto-electric induction, the basis of the electric generator.

Electrical engineers usually regard Faraday as the "father" of their profession, but Faraday himself was not primarily interested in the practical applications of his discoveries. His driving motivation was to understand the forces of nature, such as electricity and magnetism, and the relationship between them. Faraday delighted in telling others about science, and studied what made a good scientific lecturer. At the Royal Institution he introduced the Friday Evening Discourses and also the Christmas Lectures for Young People, now televised in the UK every Christmas.

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SUBJECT AREA: Electricity, Public utilities

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Gramme trained as a carpenter and showed an early talent for working with machinery. Moving to Paris he found employment in the Alliance factory as a model maker. With a growing interest in electricity he left to become an instrument maker with Heinrich Daniel Rühmkorff. In 1870 he patented the uniformly wound ring-armature dynamo with which his name is associated. Together with Hippolyte Fontaine, in 1871 Gramme opened a factory to manufacture his dynamos. They rapidly became a commercial success for both arc lighting and electrochemical purposes, international publicity being achieved at exhibitions in Vienna, Paris and Philadelphia. It was the realization that a Gramme machine was capable of running as a motor, i.e. the reversibility of function, that illustrated the entire concept of power transmission by electricity. This was first publicly demonstrated in 1873. In 1874 Gramme reduced the size and increased the efficiency of his generators by relying completely on the principle of self-excitation. It was the first practical machine in which were combined the features of continuity of commutation, self-excitation, good lamination of the armature core and a reasonably good magnetic circuit. This dynamo, together with the self-regulating arc lamps then available, made possible the innumerable electric-lighting schemes that followed. These were of the greatest importance in demonstrating that electric lighting was a practical and economic means of illumination. Gramme also designed an alternator to operate Jablochkoff candles. For some years he took an active part in the operations of the Société Gramme and also experimented in his own workshop without collaboration, but made no further contribution to electrical technology.

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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