union+electric+company

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

general ['dʒenərəl]

1 adjective

(a) (common) général;

∎ as a general rule en règle générale, en général;

∎ in general terms en termes généraux;

∎ in the general interest dans l'intérêt de tous;

∎ the general feeling was that he should have won le sentiment général était qu'il aurait dû gagner;

∎ there was a general movement to leave the room la plupart des gens se sont levés pour sortir

(b) (approximate) général;

∎ a general resemblance une vague ressemblance;

∎ to go in the general direction of sth se diriger plus ou moins vers qch;

∎ their house is over in that general direction leur maison se trouve vers là-bas

(c) (widespread) général, répandu;

∎ a general opinion une opinion générale ou répandue;

∎ to be in general use être d'usage courant ou répandu;

∎ to come into general use se généraliser;

∎ this word is no longer in general use ce mot est tombé en désuétude;

∎ there is general agreement on the matter il y a consensus sur la question;

∎ this kind of attitude is fairly general in Europe ce genre d'attitude est assez répandu en Europe;

∎ the rain has been pretty general il a plu un peu partout

(d) (overall → outline, plan, impression) d'ensemble;

∎ the general effect is quite pleasing le résultat général est assez agréable;

∎ I get the general idea je vois en gros;

∎ he gave her a general idea or outline of his work il lui a décrit son travail dans les grandes lignes;

∎ the general tone of her remarks was that… ce qui ressortait de ses remarques c'est que…;

∎ he made himself a general nuisance il a été embêtant à tout point de vue

(e) (ordinary)

∎ this book is for the general reader ce livre est destiné au lecteur moyen;

∎ the general public le grand public

2 noun

(a) (in reasoning)

∎ to go from the general to the particular aller du général au particulier

(b) Military général m

(c) (domestic servant) bonne f à tout faire

3 in general adverb

en général

►► Banking general account manager chargé(e) m,f de clientèle grand public;

general accounts comptabilité f générale;

American General Accounting Office = Cour des comptes américaine;

Finance & Commerce general and administrative expenses frais mpl généraux et frais de gestion;

Commerce general agent agent m d'affaires;

General Agreement on Tariffs and Trade accord m général sur les tarifs douaniers et le commerce;

Medicine general anaesthetic anesthésie f générale;

General Assembly assemblée f générale;

Australian Cinema general (audience) = tous publics;

Insurance general average avarie f commune;

Commerce general business (on agenda) questions fpl diverses;

formerly School General Certificate of Education = certificat de fin d'études secondaires en deux étapes (O level et A level) dont la première est aujourd'hui remplacée par le GCSE;

School General Certificate of Secondary Education = premier examen de fin de scolarité en Grande-Bretagne; see also GCSE ;

American general dealer bazar m;

University general degree = licence comportant plusieurs matières;

American general delivery poste f restante;

general election élections fpl législatives;

British General Electric Company = société britannique fabriquant des produits électriques, électroniques et de télécommunications;

American School general equivalency diploma = aux États-Unis, diplôme d'études secondaires pour adultes souvent obtenu par correspondance;

Accountancy & Finance general expenses frais mpl généraux;

general headquarters (grand) quartier m général;

general hospital centre m hospitalier;

general knowledge culture f générale;

Accountancy general ledger grand-livre m;

Law general lien privilège m général;

general management committee comité m de direction;

general manager directeur(trice) m,f général(e);

British General Medical Council ≃ conseil m de l'ordre des médecins;

general meeting assemblée f générale;

British General, Municipal, Boilermakers and Allied Trades Union = important syndicat britannique;

British General and Municipal Workers' Union = syndicat britannique des employés des collectivités locales;

British School General National Vocational Qualification = formation professionnelle sur deux ans que l'on peut suivre à partir de seize ans;

Finance general obligation bond emprunt m de collectivité locale;

general officer général m en chef; Accountancy &

Finance British general overheads, American general overhead frais mpl d'administration générale;

General Post Office (in Britain) = titre officiel de la Poste britannique avant 1969; (in US) = les services postaux américains;

general practice médecine f générale;

general practitioner médecin m généraliste, omnipraticien(enne) m,f;

Finance general price level niveau m général des prix;

general secretary (of trade union, political party) secrétaire mf général(e);

general staff état-major m;

general store bazar m;

general strike grève f générale;

the General Strike = la grève de mai 1926 en Grande-Bretagne, lancée par les syndicats par solidarité avec les mineurs;

School General Studies ≃ cours m de culture générale;

General Synod = le Synode général de l'Église anglicane;

Finance general wage level niveau m général des salaires

1) Компьютерная техника: Expensive Edition

2) Военный термин: educational establishment, electromagnetic environment, electronic engineering, electronic environment, electronic equipment, elements of expense, emergency equipment, emergency establishment, engagement effectiveness, expiration of enlistment, external environment

3) Техника: electrically erased, electromagnetic evaluation, electronic editing, electronics engineering division, electronics-to-electronics, energy exchanger, exoelectron emission

4) Математика: Explicit Equality

5) Религия: Evangelism Explosion

6) Железнодорожный термин: Ellis and Eastern Company

7) Грубое выражение: Exciting Ejaculations

8) Сокращение: EW Expendable, Early English, Electrical Engineer, Electrical Engineering, Electrical or Electronics Engineer, Electronics Engineer, Envoy Extraordinary, earth entry, employee, end to end, experimental establishment, errors excepted, exclusive economic zone, Early Edition, Early Entry, Earth Electrode, Eased Edges (lumber industry), Easter Egg (hidden area of a program or site), Eastern European, Ecosystem Evaluation, Edge Enhancement (video), Edward Elric (protagonist of anime series FullMetal Alchemist), Electrical Energy, Electrical Essence (forum), Electronic Encyclopedia, Electronic Engineer, Element Energy, Elementary Education, Elite Edition, Empire Earth (game), End-Effector, Energy Expenditure, Energy and Environment, Engraver's Express, Inc, Enter Exponent (calculator function), Enterprise Edition (Java2), Environmental Education, Environmental Engineering, Eosinophilic Esophagitis, Epreuve d'essai (French: proof print), Equal Exchange, Equipment Engineering, Ersatz Elevator (Lemony Snicket), Escape and Evasion, Estonia, Estoy Escuchando (Spanish: now playing), Et Cetera, Et Cetera, Eternal Echo (band), Eternal Energy, Eternity Engine (gaming), Ether Extract, Ethylmalonic Encephalopathy, Euskadiko Ezquerra (Basque Division of the Spanish Left Wing Party), Evaluation Engineering, Evil Empire (gaming), Evropaiki Enosi (Greek: European Union), Excess Emission(s), Execution Environment, Executive Editor, Exercise Experience, Exotic Ethnic (gaming), Experts Exchange, Exponent, Exponential Elevation, Expressed Emotion (psychiatric term used in schizophrenia settings), Expression Engine (Pmachine.com), Extended Edition (DVD movie version), Extended Employment program, Extended Essay (International Baccalaureate), Extreme Edition (Intel Pentium 4), Exudative Epidermitis (Porcine Circovirus 2), emergency establishment (US DoD), раннеанглийский язык

9) Вычислительная техника: Extended Edition, Emotion Engine (Sony, Playstation)

10) Экология: ecological efficiency

11) Деловая лексика: Economic Empowerment

12) Образование: English Essay

13) Сетевые технологии: Enterprise Edition

14) ЕБРР: energy efficiency

15) Полимеры: external environments

16) Программирование: Enter Exponent

17) Химическое оружие: emergency exit, engineering evaluation

18) Расширение файла: Extended Edition (IBM)

19) SAP.тех. работник

20) Электротехника: electrical equipment

21) НАСА: Exploration Era

22) Программное обеспечение: Easy Editor, Expected Error

23) Единицы измерений: English Equivalent

24) AMEX. El Paso Electric Company

25) Международная торговля: Export Enforcement

1) Компьютерная техника: Expensive Edition

2) Военный термин: educational establishment, electromagnetic environment, electronic engineering, electronic environment, electronic equipment, elements of expense, emergency equipment, emergency establishment, engagement effectiveness, expiration of enlistment, external environment

3) Техника: electrically erased, electromagnetic evaluation, electronic editing, electronics engineering division, electronics-to-electronics, energy exchanger, exoelectron emission

4) Математика: Explicit Equality

5) Религия: Evangelism Explosion

6) Железнодорожный термин: Ellis and Eastern Company

7) Грубое выражение: Exciting Ejaculations

8) Сокращение: EW Expendable, Early English, Electrical Engineer, Electrical Engineering, Electrical or Electronics Engineer, Electronics Engineer, Envoy Extraordinary, earth entry, employee, end to end, experimental establishment, errors excepted, exclusive economic zone, Early Edition, Early Entry, Earth Electrode, Eased Edges (lumber industry), Easter Egg (hidden area of a program or site), Eastern European, Ecosystem Evaluation, Edge Enhancement (video), Edward Elric (protagonist of anime series FullMetal Alchemist), Electrical Energy, Electrical Essence (forum), Electronic Encyclopedia, Electronic Engineer, Element Energy, Elementary Education, Elite Edition, Empire Earth (game), End-Effector, Energy Expenditure, Energy and Environment, Engraver's Express, Inc, Enter Exponent (calculator function), Enterprise Edition (Java2), Environmental Education, Environmental Engineering, Eosinophilic Esophagitis, Epreuve d'essai (French: proof print), Equal Exchange, Equipment Engineering, Ersatz Elevator (Lemony Snicket), Escape and Evasion, Estonia, Estoy Escuchando (Spanish: now playing), Et Cetera, Et Cetera, Eternal Echo (band), Eternal Energy, Eternity Engine (gaming), Ether Extract, Ethylmalonic Encephalopathy, Euskadiko Ezquerra (Basque Division of the Spanish Left Wing Party), Evaluation Engineering, Evil Empire (gaming), Evropaiki Enosi (Greek: European Union), Excess Emission(s), Execution Environment, Executive Editor, Exercise Experience, Exotic Ethnic (gaming), Experts Exchange, Exponent, Exponential Elevation, Expressed Emotion (psychiatric term used in schizophrenia settings), Expression Engine (Pmachine.com), Extended Edition (DVD movie version), Extended Employment program, Extended Essay (International Baccalaureate), Extreme Edition (Intel Pentium 4), Exudative Epidermitis (Porcine Circovirus 2), emergency establishment (US DoD), раннеанглийский язык

9) Вычислительная техника: Extended Edition, Emotion Engine (Sony, Playstation)

10) Экология: ecological efficiency

11) Деловая лексика: Economic Empowerment

12) Образование: English Essay

13) Сетевые технологии: Enterprise Edition

14) ЕБРР: energy efficiency

15) Полимеры: external environments

16) Программирование: Enter Exponent

17) Химическое оружие: emergency exit, engineering evaluation

18) Расширение файла: Extended Edition (IBM)

19) SAP.тех. работник

20) Электротехника: electrical equipment

21) НАСА: Exploration Era

22) Программное обеспечение: Easy Editor, Expected Error

23) Единицы измерений: English Equivalent

24) AMEX. El Paso Electric Company

25) Международная торговля: Export Enforcement

1) Компьютерная техника: Expensive Edition

2) Военный термин: educational establishment, electromagnetic environment, electronic engineering, electronic environment, electronic equipment, elements of expense, emergency equipment, emergency establishment, engagement effectiveness, expiration of enlistment, external environment

3) Техника: electrically erased, electromagnetic evaluation, electronic editing, electronics engineering division, electronics-to-electronics, energy exchanger, exoelectron emission

4) Математика: Explicit Equality

5) Религия: Evangelism Explosion

6) Железнодорожный термин: Ellis and Eastern Company

7) Грубое выражение: Exciting Ejaculations

8) Сокращение: EW Expendable, Early English, Electrical Engineer, Electrical Engineering, Electrical or Electronics Engineer, Electronics Engineer, Envoy Extraordinary, earth entry, employee, end to end, experimental establishment, errors excepted, exclusive economic zone, Early Edition, Early Entry, Earth Electrode, Eased Edges (lumber industry), Easter Egg (hidden area of a program or site), Eastern European, Ecosystem Evaluation, Edge Enhancement (video), Edward Elric (protagonist of anime series FullMetal Alchemist), Electrical Energy, Electrical Essence (forum), Electronic Encyclopedia, Electronic Engineer, Element Energy, Elementary Education, Elite Edition, Empire Earth (game), End-Effector, Energy Expenditure, Energy and Environment, Engraver's Express, Inc, Enter Exponent (calculator function), Enterprise Edition (Java2), Environmental Education, Environmental Engineering, Eosinophilic Esophagitis, Epreuve d'essai (French: proof print), Equal Exchange, Equipment Engineering, Ersatz Elevator (Lemony Snicket), Escape and Evasion, Estonia, Estoy Escuchando (Spanish: now playing), Et Cetera, Et Cetera, Eternal Echo (band), Eternal Energy, Eternity Engine (gaming), Ether Extract, Ethylmalonic Encephalopathy, Euskadiko Ezquerra (Basque Division of the Spanish Left Wing Party), Evaluation Engineering, Evil Empire (gaming), Evropaiki Enosi (Greek: European Union), Excess Emission(s), Execution Environment, Executive Editor, Exercise Experience, Exotic Ethnic (gaming), Experts Exchange, Exponent, Exponential Elevation, Expressed Emotion (psychiatric term used in schizophrenia settings), Expression Engine (Pmachine.com), Extended Edition (DVD movie version), Extended Employment program, Extended Essay (International Baccalaureate), Extreme Edition (Intel Pentium 4), Exudative Epidermitis (Porcine Circovirus 2), emergency establishment (US DoD), раннеанглийский язык

9) Вычислительная техника: Extended Edition, Emotion Engine (Sony, Playstation)

10) Экология: ecological efficiency

11) Деловая лексика: Economic Empowerment

12) Образование: English Essay

13) Сетевые технологии: Enterprise Edition

14) ЕБРР: energy efficiency

15) Полимеры: external environments

16) Программирование: Enter Exponent

17) Химическое оружие: emergency exit, engineering evaluation

18) Расширение файла: Extended Edition (IBM)

19) SAP.тех. работник

20) Электротехника: electrical equipment

21) НАСА: Exploration Era

22) Программное обеспечение: Easy Editor, Expected Error

23) Единицы измерений: English Equivalent

24) AMEX. El Paso Electric Company

25) Международная торговля: Export Enforcement

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: Architecture and building, Automotive engineering, Electricity, Electronics and information technology, Metallurgy, Photography, film and optics, Public utilities, Recording, Telecommunications

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He was the son of Samuel Edison, who was in the timber business. His schooling was delayed due to scarlet fever until 1855, when he was 8½ years old, but he was an avid reader. By the age of 14 he had a job as a newsboy on the railway from Port Huron to Detroit, a distance of sixty-three miles (101 km). He worked a fourteen-hour day with a stopover of five hours, which he spent in the Detroit Free Library. He also sold sweets on the train and, later, fruit and vegetables, and was soon making a profit of $20 a week. He then started two stores in Port Huron and used a spare freight car as a laboratory. He added a hand-printing press to produce 400 copies weekly of The Grand Trunk Herald, most of which he compiled and edited himself. He set himself to learn telegraphy from the station agent at Mount Clements, whose son he had saved from being run over by a freight car.

At the age of 16 he became a telegraphist at Port Huron. In 1863 he became railway telegraphist at the busy Stratford Junction of the Grand Trunk Railroad, arranging a clock with a notched wheel to give the hourly signal which was to prove that he was awake and at his post! He left hurriedly after failing to hold a train which was nearly involved in a head-on collision. He usually worked the night shift, allowing himself time for experiments during the day. His first invention was an arrangement of two Morse registers so that a high-speed input could be decoded at a slower speed. Moving from place to place he held many positions as a telegraphist. In Boston he invented an automatic vote recorder for Congress and patented it, but the idea was rejected. This was the first of a total of 1180 patents that he was to take out during his lifetime. After six years he resigned from the Western Union Company to devote all his time to invention, his next idea being an improved ticker-tape machine for stockbrokers. He developed a duplex telegraphy system, but this was turned down by the Western Union Company. He then moved to New York.

Edison found accommodation in the battery room of Law's Gold Reporting Company, sleeping in the cellar, and there his repair of a broken transmitter marked him as someone of special talents. His superior soon resigned, and he was promoted with a salary of $300 a month. Western Union paid him $40,000 for the sole rights on future improvements on the duplex telegraph, and he moved to Ward Street, Newark, New Jersey, where he employed a gathering of specialist engineers. Within a year, he married one of his employees, Mary Stilwell, when she was only 16: a daughter, Marion, was born in 1872, and two sons, Thomas and William, in 1876 and 1879, respectively.

He continued to work on the automatic telegraph, a device to send out messages faster than they could be tapped out by hand: that is, over fifty words per minute or so. An earlier machine by Alexander Bain worked at up to 400 words per minute, but was not good over long distances. Edison agreed to work on improving this feature of Bain's machine for the Automatic Telegraph Company (ATC) for $40,000. He improved it to a working speed of 500 words per minute and ran a test between Washington and New York. Hoping to sell their equipment to the Post Office in Britain, ATC sent Edison to England in 1873 to negotiate. A 500-word message was to be sent from Liverpool to London every half-hour for six hours, followed by tests on 2,200 miles (3,540 km) of cable at Greenwich. Only confused results were obtained due to induction in the cable, which lay coiled in a water tank. Edison returned to New York, where he worked on his quadruplex telegraph system, tests of which proved a success between New York and Albany in December 1874. Unfortunately, simultaneous negotiation with Western Union and ATC resulted in a lawsuit.

Alexander Graham Bell was granted a patent for a telephone in March 1876 while Edison was still working on the same idea. His improvements allowed the device to operate over a distance of hundreds of miles instead of only a few miles. Tests were carried out over the 106 miles (170 km) between New York and Philadelphia. Edison applied for a patent on the carbon-button transmitter in April 1877, Western Union agreeing to pay him $6,000 a year for the seventeen-year duration of the patent. In these years he was also working on the development of the electric lamp and on a duplicating machine which would make up to 3,000 copies from a stencil. In 1876–7 he moved from Newark to Menlo Park, twenty-four miles (39 km) from New York on the Pennsylvania Railway, near Elizabeth. He had bought a house there around which he built the premises that would become his "inventions factory". It was there that he began the use of his 200- page pocket notebooks, each of which lasted him about two weeks, so prolific were his ideas. When he died he left 3,400 of them filled with notes and sketches.

Late in 1877 he applied for a patent for a phonograph which was granted on 19 February 1878, and by the end of the year he had formed a company to manufacture this totally new product. At the time, Edison saw the device primarily as a business aid rather than for entertainment, rather as a dictating machine. In August 1878 he was granted a British patent. In July 1878 he tried to measure the heat from the solar corona at a solar eclipse viewed from Rawlins, Wyoming, but his "tasimeter" was too sensitive.

Probably his greatest achievement was "The Subdivision of the Electric Light" or the "glow bulb". He tried many materials for the filament before settling on carbon. He gave a demonstration of electric light by lighting up Menlo Park and inviting the public. Edison was, of course, faced with the problem of inventing and producing all the ancillaries which go to make up the electrical system of generation and distribution-meters, fuses, insulation, switches, cabling—even generators had to be designed and built; everything was new. He started a number of manufacturing companies to produce the various components needed.

In 1881 he built the world's largest generator, which weighed 27 tons, to light 1,200 lamps at the Paris Exhibition. It was later moved to England to be used in the world's first central power station with steam engine drive at Holborn Viaduct, London. In September 1882 he started up his Pearl Street Generating Station in New York, which led to a worldwide increase in the application of electric power, particularly for lighting. At the same time as these developments, he built a 1,300yd (1,190m) electric railway at Menlo Park.

On 9 August 1884 his wife died of typhoid. Using his telegraphic skills, he proposed to 19-year-old Mina Miller in Morse code while in the company of others on a train. He married her in February 1885 before buying a new house and estate at West Orange, New Jersey, building a new laboratory not far away in the Orange Valley.

Edison used direct current which was limited to around 250 volts. Alternating current was largely developed by George Westinghouse and Nicola Tesla, using transformers to step up the current to a higher voltage for long-distance transmission. The use of AC gradually overtook the Edison DC system.

In autumn 1888 he patented a form of cinephotography, the kinetoscope, obtaining film-stock from George Eastman. In 1893 he set up the first film studio, which was pivoted so as to catch the sun, with a hinged roof which could be raised. In 1894 kinetoscope parlours with "peep shows" were starting up in cities all over America. Competition came from the Latham Brothers with a screen-projection machine, which Edison answered with his "Vitascope", shown in New York in 1896. This showed pictures with accompanying sound, but there was some difficulty with synchronization. Edison also experimented with captions at this early date.

In 1880 he filed a patent for a magnetic ore separator, the first of nearly sixty. He bought up deposits of low-grade iron ore which had been developed in the north of New Jersey. The process was a commercial success until the discovery of iron-rich ore in Minnesota rendered it uneconomic and uncompetitive. In 1898 cement rock was discovered in New Village, west of West Orange. Edison bought the land and started cement manufacture, using kilns twice the normal length and using half as much fuel to heat them as the normal type of kiln. In 1893 he met Henry Ford, who was building his second car, at an Edison convention. This started him on the development of a battery for an electric car on which he made over 9,000 experiments. In 1903 he sold his patent for wireless telegraphy "for a song" to Guglielmo Marconi.

In 1910 Edison designed a prefabricated concrete house. In December 1914 fire destroyed three-quarters of the West Orange plant, but it was at once rebuilt, and with the threat of war Edison started to set up his own plants for making all the chemicals that he had previously been buying from Europe, such as carbolic acid, phenol, benzol, aniline dyes, etc. He was appointed President of the Navy Consulting Board, for whom, he said, he made some forty-five inventions, "but they were pigeonholed, every one of them". Thus did Edison find that the Navy did not take kindly to civilian interference.

In 1927 he started the Edison Botanic Research Company, founded with similar investment from Ford and Firestone with the object of finding a substitute for overseas-produced rubber. In the first year he tested no fewer than 3,327 possible plants, in the second year, over 1,400, eventually developing a variety of Golden Rod which grew to 14 ft (4.3 m) in height. However, all this effort and money was wasted, due to the discovery of synthetic rubber.

In October 1929 he was present at Henry Ford's opening of his Dearborn Museum to celebrate the fiftieth anniversary of the incandescent lamp, including a replica of the Menlo Park laboratory. He was awarded the Congressional Gold Medal and was elected to the American Academy of Sciences. He died in 1931 at his home, Glenmont; throughout the USA, lights were dimmed temporarily on the day of his funeral.

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SUBJECT AREA: Electricity, Land transport, Railways and locomotives

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Davidson, son of an Aberdeen merchant, attended Marischal College, Aberdeen, between 1819 and 1822: his studies included mathematics, mechanics and chemistry. He subsequently joined his father's grocery business, which from time to time received enquiries for yeast: to meet these, Davidson began to manufacture yeast for sale and from that start built up a successful chemical manufacturing business with the emphasis on yeast and dyes. About 1837 he started to experiment first with electric batteries and then with motors. He invented a form of electromagnetic engine in which soft iron bars arranged on the periphery of a wooden cylinder, parallel to its axis, around which the cylinder could rotate, were attracted by fixed electromagnets. These were energized in turn by current controlled by a simple commutaring device. Electric current was produced by his batteries. His activities were brought to the attention of Michael Faraday and to the scientific world in general by a letter from Professor Forbes of King's College, Aberdeen. Davidson declined to patent his inventions, believing that all should be able freely to draw advantage from them, and in order to afford an opportunity for all interested parties to inspect them an exhibition was held at 36 Union Street, Aberdeen, in October 1840 to demonstrate his "apparatus actuated by electro-magnetic power". It included: a model locomotive carriage, large enough to carry two people, that ran on a railway; a turning lathe with tools for visitors to use; and a small printing machine. In the spring of 1842 he put on a similar exhibition in Edinburgh, this time including a sawmill. Davidson sought support from railway companies for further experiments and the construction of an electromagnetic locomotive; the Edinburgh exhibition successfully attracted the attention of the proprietors of the Edinburgh 585\& Glasgow Railway (E \& GR), whose line had been opened in February 1842. Davidson built a full-size locomotive incorporating his principle, apparently at the expense of the railway company. The locomotive weighed 7 tons: each of its two axles carried a cylinder upon which were fastened three iron bars, and four electromagnets were arranged in pairs on each side of the cylinders. The motors he used were reluctance motors, the power source being zinc-iron batteries. It was named Galvani and was demonstrated on the E \& GR that autumn, when it achieved a speed of 4 mph (6.4 km/h) while hauling a load of 6 tons over a distance of 1 1/2 miles (2.4 km); it was the first electric locomotive. Nevertheless, further support from the railway company was not forthcoming, although to some railway workers the locomotive seems to have appeared promising enough: they destroyed it in Luddite reaction. Davidson staged a further exhibition in London in 1843 without result and then, the cost of battery chemicals being high, ceased further experiments of this type. He survived long enough to see the electric railway become truly practicable in the 1880s.

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PJGR / GW

SUBJECT AREA: Telecommunications

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Initially apprenticed to a carpenter, Gray soon showed an interest in chemistry, but he eventually studied electrical engineering at Oberlin College, Oberlin, Ohio, in the late 1850s. In 1869 he founded the Western Electric Manufacturing Company, where he devised an electric-needle annunciator for use in hotels and lifts and carried out experimental work aimed at the development of a means of distant-speech communication. After successful realization of a liquid-based microphone and public demonstrations of a receiver using a metal diaphragm, on 14 February 1876 he deposited a caveat of intention to file a patent claim within three months for the invention of the telephone, only to learn that Alexander Graham Bell had filed a full patent claim only three hours earlier on the same day. Following litigation, the patent was eventually awarded to Bell. In 1880 Gray was appointed Professor of Dynamic Electricity at Oberlin College, but he appears to have retained his business interests since in 1891 he was both a member of the firm of Gray and Barton and electrician to his old firm, Western Electric. Subsequently, in 1895, he invented the TelAutograph, a form of remote-writing telegraph, or facsimile, capable of operating over short distances. The system used a transmitter in which the x and y movements of a writing stylus were coupled to a pair of variable resistors. In turn, these were connected by two telegraph wires to a pair of receiving coils, which were used to control the position of a pen on a sheet of paper, thus replicating the movement of the original stylus.

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SUBJECT AREA: Domestic appliances and interiors

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Hoover was descended from a Swiss farming family called Hofer who emigrated from Basle and settled in Lancaster County, Pennsylvania, in the early eighteenth century. By 1832 the family had become tanners and lived near North Berlin in Ohio. In 1870 William Henry Hoover, who had studied at Mount Union College, bought the tannery with his brothers and soon expanded the business to make horse collars and saddlery. The firm expanded to become W.H.Hoover \& Co. In the early years of the first decade of the twentieth century, horses were beginning to be replaced by the internal combustion engine, so Hoover needed a new direction for his firm. This he found in the suction vacuum cleaner devised in 1907 by J.Murray Spangler, a cousin of Hoover's wife. The first successful cleaner of this type had been operating in England since 1901 (see Booth), but was not a portable model. Attracted by the development of the small electric motor, Spangler produced a vertical cleaner with such a motor that sucked the dust through the machine and blew it into a bag attached to the handle. Spangler applied for a patent for his invention on 14 September in the same year; it was granted for a carpet sweeper and cleaner on 2 June 1908, but Spangler was unable to market it himself and sold the rights to Hoover. The Model O machine, which ran on small wheels, was immediately manufactured and marketed. Hoover's model was the first electric, one-person-operated, domestic vacuum cleaner and was instantly successful, although the main expansion of the business was delayed for some time until the greater proportion of houses were wired for electricity. The Hoover slogan, "it beats as it sweeps as it cleans", came to be true in 1926 with the introduction of the Model 700, which was the first cleaner to offer triple-action cleaning, a process which beat, swept and sucked at the carpet. Further advances in the 1930s included the use of magnesium and the early plastics.

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