John Hopkinson

Last updated

John Hopkinson
John Hopkinson.jpg
Born(1849-07-27)27 July 1849
Died27 August 1898(1898-08-27) (aged 49)
Nationality British
Known for Hopkinson effect
Awards Royal Medal (1890)
Scientific career
Fields physics, electrical engineering

John Hopkinson, FRS, (27 July 1849 – 27 August 1898) was a British physicist, electrical engineer, Fellow of the Royal Society and President of the IEE (now the IET) twice in 1890 and 1896. He invented the three-wire (three-phase) system for the distribution of electrical power, for which he was granted a patent in 1882. He also worked in many areas of electromagnetism and electrostatics, and in 1890 was appointed professor of electrical engineering at King's College London, where he was also director of the Siemens Laboratory. [1]


Hopkinson's law, the magnetic counterpart to Ohm's law, is named after him.

Life and career

John Hopkinson was born in Manchester, the eldest of 5 children. His father, also called John, was a mechanical engineer. He was educated at Queenwood School in Hampshire and Owens College in Manchester. He won a scholarship to Trinity College, Cambridge in 1867 and graduated in 1871 as Senior Wrangler, having placed first in the demanding Cambridge Mathematical Tripos examination. [2] During this time he also studied for and passed the examination for a BSc from the University of London. Hopkinson could have followed a purely academic career but instead chose engineering as his vocation. He was a Cambridge Apostle.

After working first in his father's engineering works, Hopkinson took a position in 1872 as an engineering manager in the lighthouse engineering department of Chance Brothers and Company in Smethwick. In 1877 Hopkinson was elected a Fellow of the Royal Society in recognition of his application of Maxwell's theory of electromagnetism to problems of electrostatic capacity and residual charge. In 1878 he moved to London to work as a consulting engineer, focusing particularly on developing his ideas about how to improve the design and efficiency of dynamos. Hopkinson's most important contribution was his three-wire distribution system, patented in 1882. In 1883 Hopkinson showed mathematically that it was possible to connect two alternating current dynamos in parallel-—a problem that had long bedevilled electrical engineers. [3] [4] He also studied magnetic permeability at high temperature, and discovered what was later called the Hopkinson peak effect. [5]

The series-parallel method of electric motor control, for which Hopkinson was granted a British patent in 1881, would prove to be an important advance in the development of electric railways. [6] He applied for a US patent in 1892, triggering an interference proceeding against American inventor Rudolph M Hunter, who had been granted a US patent for the method in 1888. [7] The US Patent Office affirmed Hopkinson's claim to priority of invention, but his British patent expired before the case was resolved, rendering him ineligible for a US patent (his US patent, had one been issued, would have expired concurrently with his British patent). [8]

Hopkinson twice held the office of President of the Institution of Electrical Engineers. During his second term, Hopkinson proposed that the Institution should make available the technical knowledge of electrical engineers for the defence of the country. In 1897 the Volunteer Corps of Electrical Engineers was formed and Hopkinson became major in command of the corps.

Personal life and legacy

Memorial plaque at Cambridge Memorial to John Hopkinson, Free School Lane - - 699093.jpg
Memorial plaque at Cambridge

On 27 August 1898, Hopkinson and three of his six children, John Gustave, Alice and Lina Evelyn, were killed in a mountaineering accident on the Petite Dent de Veisivi, Val d'Hérens, in the Pennine Alps, Switzerland.

As a memorial to John Hopkinson and his son, the 1899 extension to the Engineering Laboratory in the New Museums Site of the University of Cambridge was named after him. A plaque commemorating this is fixed to the wall in Free School Lane. [9] The Hopkinson and Imperial Chemical Industries Professorship of Applied Thermodynamics is named in his honour. [10]

There is a memorial sundial to Alice Hopkinson in the gardens of Newnham College, Cambridge from which she had recently graduated; the Lina Evelyn Hopkinson Scholarship is awarded to pupils at Wimbledon High School for English Literature.

At the Victoria University of Manchester the Electro-technical Laboratory (1912) in Coupland Street was named after him. [11]

His sons Bertram and Cecil, wife Evelyn and daughter Ellen (married James Alfred Ewing in 1912) are buried in the Ascension Parish Burial Ground, Cambridge; the rest of the family are interred in Switzerland.

See also

Related Research Articles

Charles Proteus Steinmetz 19th and 20th-century mathematician and electrical engineer

Charles Proteus Steinmetz was a German-born American mathematician and electrical engineer and professor at Union College. He fostered the development of alternating current that made possible the expansion of the electric power industry in the United States, formulating mathematical theories for engineers. He made ground-breaking discoveries in the understanding of hysteresis that enabled engineers to design better electromagnetic apparatus equipment especially electric motors for use in industry.

John Ambrose Fleming English electrical engineer and physicist

Sir John Ambrose Fleming FRS was an English electrical engineer and physicist who invented the first thermionic valve or vacuum tube, designed the radio transmitter with which the first transatlantic radio transmission was made, and also established the right-hand rule used in physics.

1880s Decade of the Gregorian calendar

The 1880s was a decade that began on January 1, 1880, and ended on December 31, 1889. The decade occurred at the core period of the Second Industrial Revolution. The modern city as well as the sky-scraper rose to prominence in this decade as well, contributing to the economic prosperity of the time. The 1880s were also part of the Gilded Age, in the United States, which lasted from 1874 to 1907.

Electric generator device that converts other energy to electrical energy

In electricity generation, a generator is a device that converts motive power into electrical power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all of the power for electric power grids.

Elihu Thomson American inventor

Elihu Thomson was an English-born American engineer and inventor who was instrumental in the founding of major electrical companies in the United States, the United Kingdom and France.

Pavel Yablochkov Russian engineer

Pavel Nikolayevich Yablochkov was a Russian electrical engineer, businessman and the inventor of the Yablochkov candle and the transformer.

Alfred Ewing Scottish physicist, engineer

Sir James Alfred EwingMInstitCE was a Scottish physicist and engineer, best known for his work on the magnetic properties of metals and, in particular, for his discovery of, and coinage of the word, hysteresis.

Sebastian Ziani de Ferranti British engineer

Sebastian Pietro Innocenzo Adhemar Ziani de Ferranti was a British electrical engineer and inventor.

Charles Hesterman Merz was a British electrical engineer who pioneered the use of high-voltage three-phase AC power distribution in the United Kingdom, building a system in the North East of England in the early 20th century that became the model for the country's National Grid.

Bertram Hopkinson was a British patent lawyer and Professor of Mechanism and Applied Mechanics at Cambridge University. In this position he researched flames, explosions and metallurgy and became a pioneer designer of the internal combustion engine.

Moritz Immisch was an Electrical engineer, watchmaker and inventor.

Alexander Siemens German engineer

Alexander Siemens was a German electrical engineer.

Reinhold Rudenberg was a German-American electrical engineer and inventor, credited with many innovations in the electric power and related fields. Aside from improvements in electric power equipment, especially large alternating current generators, among others were the electrostatic-lens electron microscope, carrier-current communications on power lines, a form of phased array radar, an explanation of power blackouts, preferred number series, and the number prefix "Giga-".

Charles Inglis (engineer) British civil engineer

Sir Charles Edward Inglis, OBE, FRS was a British civil engineer. The son of a doctor, he was educated at Cheltenham College and won a scholarship to King's College, Cambridge, where he would later forge a career as an academic. Inglis spent a two-year period with the engineering firm run by John Wolfe-Barry before he returned to King's College as a lecturer. Working with Professors James Alfred Ewing and Bertram Hopkinson, he made several important studies into the effects of vibration on structures and defects on the strength of plate steel.

Edward Hopkinson was a British electrical engineer and Conservative politician.

Alfred Hopkinson British politician

Sir Alfred Hopkinson was an English lawyer, academic and politician who served as a Member of Parliament (MP) for two three-year periods, separated by nearly thirty years.

Auguste de Méritens French electrical engineer

Baron Auguste de Méritens was a French electrical engineer of the 19th century.

James Edward Henry Gordon was a British electrical engineer, the son of James Alexander Gordon (1793-1872). He took his B.A. at Caius College, Cambridge in 1876.

Joseph Nasmith was a British consulting textile engineer, editor of the Textile Recorder and author, known for his work on the history and state of the art of the textile industry, particularly cotton spinning and cotton mill construction and engineering.

Thomas Parker was an English electrical engineer, inventor and industrialist. He patented improvements in lead-acid batteries and dynamos, and was a pioneer of manufacturing equipment that powered electric tramways and electric lighting. He invented the smokeless fuel Coalite. He formed the first company to distribute electricity over a wide area.


  1. Oxford Dictionary of National Biography: Hopkinson, John by T. H. Beare
  2. "Hopkinson, John (HPKN867J)". A Cambridge Alumni Database. University of Cambridge.
  3. Original papers on dynamo machinery and allied subjects (London, Whittaker, 1893)
  5. Hopkinson, J. (1889). "Magnetic and Other Physical Properties of Iron at a High Temperature". Philosophical Transactions of the Royal Society of London A. 180: 443–465. Bibcode:1889RSPTA.180..443H. doi: 10.1098/rsta.1889.0014 . JSTOR   90545.
  6. Great Britain Patent 2989 of 1881.
  7. US Patent 385,055.
  8. Hopkinson v. Hunter (74 O.G., 653). United States Patent Office (1897). Decisions of the commissioner of patents and of the United States courts in patent and trade-mark and copyright cases. 1896. Washington, DC: Government Printing Office. pp. 1-5.
  9. John Hopkinson biography
  10. Cambridge University - 125 Years of Engineering Excellence
  11. The Book of Manchester and Salford. Manchester: George Falkner & Sons, 1929; p. 73

Further reading