André-Marie Ampère

André-Marie Ampère (/ˈæmpɪər/;[1] French: [ɑ̃pɛʁ]; 20 January 1775 – 10 June 1836)[2] was a French physicist and mathematician who was one of the founders of the science of classical electromagnetism, which he referred to as "electrodynamics". He is also the inventor of numerous applications, such as the solenoid (a term coined by him) and the electrical telegraph. An autodidact, Ampère was a member of the French Academy of Sciences and professor at the École polytechnique and the Collège de France.

The SI unit of measurement of electric current, the ampere, is named after him. His name is also one of the 72 names inscribed on the Eiffel Tower.

André-Marie Ampère
Ampere Andre 1825
Engraving of André-Marie Ampère
Born20 January 1775
Died10 June 1836 (aged 61)
Known forAmpère's circuital law
Ampère's force law
Avogadro-Ampère hypothesis
Scientific career
InstitutionsÉcole Polytechnique
André-Marie Ampère signature

Early life

André-Marie Ampère was born on 20 January 1775 to Jean-Jacques Ampère, a prosperous businessman, and Jeanne Antoinette Desutières-Sarcey Ampère, during the height of the French Enlightenment. He spent his childhood and adolescence at the family property at Poleymieux-au-Mont-d'Or near Lyon.[3] Jean-Jacques Ampère, a successful merchant, was an admirer of the philosophy of Jean-Jacques Rousseau, whose theories of education (as outlined in his treatise Émile) were the basis of Ampère's education. Rousseau believed that young boys should avoid formal schooling and pursue instead an "education direct from nature." Ampère's father actualized this ideal by allowing his son to educate himself within the walls of his well-stocked library. French Enlightenment masterpieces such as Georges-Louis Leclerc, comte de Buffon's Histoire naturelle, générale et particulière (begun in 1749) and Denis Diderot and Jean le Rond d'Alembert's Encyclopédie (volumes added between 1751 and 1772) thus became Ampère's schoolmasters. The young Ampère, however, soon resumed his Latin lessons, which enabled him to master the works of Leonhard Euler and Daniel Bernoulli.[4]

French Revolution

In addition, Ampère used his access to the latest books to begin teaching himself advanced mathematics at age 12. In later life Ampère claimed that he knew as much about mathematics and science when he was eighteen as ever he knew; but, a polymath, his reading embraced history, travels, poetry, philosophy, and the natural sciences.[4] His mother was a devout woman, so Ampère was also initiated into the Catholic faith along with Enlightenment science. The French Revolution (1789–99) that began during his youth was also influential: Ampère's father was called into public service by the new revolutionary government,[5] becoming a justice of the peace in a small town near Lyon. When the Jacobin faction seized control of the Revolutionary government in 1792, his father Jean-Jacques Ampère resisted the new political tides, and he was guillotined on 24 November 1793, as part of the Jacobin purges of the period.

In 1796 Ampère met Julie Carron, and in 1799 they were married. André-Marie Ampère took his first regular job in 1799 as a mathematics teacher, which gave him the financial security to marry Carron and father his first child, Jean-Jacques (named after his father), the next year. (Jean-Jacques Ampère eventually achieved his own fame as a scholar of languages). Ampère's maturation corresponded with the transition to the Napoleonic regime in France, and the young father and teacher found new opportunities for success within the technocratic structures favoured by the new French First Consul. In 1802 Ampère was appointed a professor of physics and chemistry at the École Centrale in Bourg-en-Bresse, leaving his ailing wife and infant son Jean-Jacques Antoine Ampère in Lyon. He used his time in Bourg to research mathematics, producing Considérations sur la théorie mathématique de jeu (1802; "Considerations on the Mathematical Theory of Games"), a treatise on mathematical probability that he sent to the Paris Academy of Sciences in 1803.

Teaching career

Ampère - Essai sur la philosophie des sciences, 1838 - 3912601 323893 1 00011
Essai sur la philosophie des sciences

After the death of his wife in July 1803, Ampère moved to Paris, where he began a tutoring post at the new École Polytechnique in 1804. Despite his lack of formal qualifications, Ampère was appointed a professor of mathematics at the school in 1809. As well as holding positions at this school until 1828, in 1819 and 1820 Ampère offered courses in philosophy and astronomy, respectively, at the University of Paris, and in 1824 he was elected to the prestigious chair in experimental physics at the Collège de France. In 1814 Ampère was invited to join the class of mathematicians in the new Institut Impérial, the umbrella under which the reformed state Academy of Sciences would sit.

Ampère engaged in a diverse array of scientific inquiries during the years leading up to his election to the academy—writing papers and engaging in topics from mathematics and philosophy to chemistry and astronomy, which was customary among the leading scientific intellectuals of the day. Ampère claimed that "at eighteen years he found three culminating points in his life, his First Communion, the reading of Antoine Leonard Thomas's "Eulogy of Descartes", and the Taking of the Bastille. On the day of his wife's death he wrote two verses from the Psalms, and the prayer, 'O Lord, God of Mercy, unite me in Heaven with those whom you have permitted me to love on earth.' In times of duress he would take refuge in the reading of the Bible and the Fathers of the Church."[6]

For a time he took into his family the young student Frédéric Ozanam (1813–1853), one of the founders of the Conference of Charity, later known as the Society of Saint Vincent de Paul. Through Ampère, Ozanam had contact with leaders of the neo-Catholic movement, such as François-René de Chateaubriand, Jean-Baptiste Henri Lacordaire, and Charles Forbes René de Montalembert. Ozanam was beatified by Pope John Paul II in 1998.

Work in electromagnetism

In September 1820, Ampère's friend and eventual eulogist François Arago showed the members of the French Academy of Sciences the surprising discovery of Danish physicist Hans Christian Ørsted that a magnetic needle is deflected by an adjacent electric current. Ampère began developing a mathematical and physical theory to understand the relationship between electricity and magnetism. Furthering Ørsted's experimental work, Ampère showed that two parallel wires carrying electric currents attract or repel each other, depending on whether the currents flow in the same or opposite directions, respectively - this laid the foundation of electrodynamics. He also applied mathematics in generalizing physical laws from these experimental results. The most important of these was the principle that came to be called Ampère's law, which states that the mutual action of two lengths of current-carrying wire is proportional to their lengths and to the intensities of their currents. Ampère also applied this same principle to magnetism, showing the harmony between his law and French physicist Charles Augustin de Coulomb's law of magnetic action. Ampère's devotion to, and skill with, experimental techniques anchored his science within the emerging fields of experimental physics.

Ampère also provided a physical understanding of the electromagnetic relationship, theorizing the existence of an "electrodynamic molecule" (the forerunner of the idea of the electron) that served as the component element of both electricity and magnetism. Using this physical explanation of electromagnetic motion, Ampère developed a physical account of electromagnetic phenomena that was both empirically demonstrable and mathematically predictive. In 1827 Ampère published his magnum opus, Mémoire sur la théorie mathématique des phénomènes électrodynamiques uniquement déduite de l’experience (Memoir on the Mathematical Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience), the work that coined the name of his new science, electrodynamics, and became known ever after as its founding treatise.

In 1827 Ampère was elected a Foreign Member of the Royal Society and in 1828, a foreign member of the Royal Swedish Academy of Science.[7]



In recognition of his contribution to the creation of modern electrical science, an international convention, signed at the 1881 International Exposition of Electricity, established the ampere as a standard unit of electrical measurement, along with the coulomb, volt, ohm, and watt, which are named, respectively, after Ampère's contemporaries Charles-Augustin de Coulomb of France, Alessandro Volta of Italy, Georg Ohm of Germany, and James Watt of Scotland. Ampère's name is one of the 72 names inscribed on the Eiffel Tower.

Several items are named after Ampère; many streets and squares, schools, a Lyon metro station, and an electric ferry in Norway.[9]



  1. ^ "Ampère". Random House Webster's Unabridged Dictionary.
  2. ^ Dictionary of Scientific Biography. United States of America: Charles Scribner's Sons. 1970.
  3. ^ "Andre-Marie Ampere". IEEE Global History Network. IEEE. Retrieved 21 July 2011.
  4. ^ a b  One or more of the preceding sentences incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "Ampère, André Marie" . Encyclopædia Britannica. 1 (11th ed.). Cambridge University Press. pp. 878–879.
  5. ^ [1] Biography of Andre Marie Ampere
  6. ^ "Catholic Encyclopedia". Retrieved 29 December 2007.
  7. ^ "Library and Archive Catalogue". Royal Society. Retrieved 13 March 2012.
  8. ^ Index biographique des membres et associés de l'Académie royale de Belgique (1769–2005) p. 15
  9. ^ "Batterifergen har måttet stå over avganger. Nå er løsningen klar". Teknisk Ukeblad. Retrieved 19 November 2016.

Further reading

  • Williams, L. Pearce (1970). "Ampère, André-Marie". Dictionary of Scientific Biography. 1. New York: Charles Scribner's Sons. pp. 139–147. ISBN 978-0-684-10114-9.
  • Hofmann, James R. (1995). André-Marie Ampère. Oxford: Blackwell. ISBN 978-0631178491.

External links

1775 in France

Events from the year 1775 in France.

1836 in France

Events from the year 1836 in France.


The ampere (; symbol: A), often shortened to "amp", is the base unit of electric current in the International System of Units (SI). It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics.

The International System of Units defines the ampere in terms of other base units by measuring the electromagnetic force between electrical conductors carrying electric current. The earlier CGS measurement system had two different definitions of current, one essentially the same as the SI's and the other using electric charge as the base unit, with the unit of charge defined by measuring the force between two charged metal plates. The ampere was then defined as one coulomb of charge per second. In SI, the unit of charge, the coulomb, is defined as the charge carried by one ampere during one second.

New definitions, in terms of invariant constants of nature, specifically the elementary charge, will take effect on 20 May 2019.

Ampere station

Ampere, formerly known as The Crescent, is a defunct stop on New Jersey Transit's Montclair-Boonton Line in the city of East Orange, Essex County, New Jersey, United States. A station was first built there in 1890 to service to new Crocker Wheeler plant in the district. The stop was named in honor of André-Marie Ampère, a pioneer in electrodynamics and reconstructed as a new Renaissance Revival station in 1908. Ampere was the second stop on the branch west of Newark Broad Street Station until 1984, when the Roseville Avenue station was closed. In June of that year, the station, along with 42 others, was entered into the National Register of Historic Places. In 1986, after continuous deterioration, New Jersey Transit demolished the westbound shelter built in 1921. The agency discontinued rail service to Ampere on April 7, 1991. The entire station was demolished in 1995.

Ampère's circuital law

In classical electromagnetism, Ampère's circuital law (not to be confused with Ampère's force law that André-Marie Ampère discovered in 1823) relates the integrated magnetic field around a closed loop to the electric current passing through the loop. James Clerk Maxwell (not Ampère) derived it using hydrodynamics in his 1861 paper "On Physical Lines of Force" and it is now one of the Maxwell equations, which form the basis of classical electromagnetism.

Ampère Prize

The Prix Ampère de l’Électricité de France is a scientific prize awarded annually by the French Academy of Sciences. Founded in 1974 in honor of André-Marie Ampère to celebrate his 200th birthday in 1975, the award is granted to one or more French scientists for outstanding research work in mathematics or physics. The monetary award is 30,500 euro, funded by Électricité de France.


André-Marie or André Marie is a French compound given name. Notable people with the name include:

André Marie, French Radical politician.

André Marie Constant Duméril (1774-1860), a French zoologist

André Marie Jean Jacques Dupin (1783-1865), a French advocate

André-Marie Ampère (1775-1836), a French physicist

André-Marie Mbida (1917-1980), the first Prime Minister of pre-independent Cameroon

Collège-lycée Ampère

The Collège-lycée Ampère is a famous school located in the 2nd arrondissement of Lyon.


A galvanometer is an electromechanical instrument used for detecting and indicating an electric current. A galvanometer works as an actuator, by producing a rotary deflection (of a "pointer"), in response to electric current flowing through a coil in a constant magnetic field. Early galvanometers were not calibrated, but their later developments were used as measuring instruments, called ammeters, to measure the current flowing through an electric circuit.

Galvanometers developed from the observation that the needle of a magnetic compass is deflected near a wire that has electric current flowing through it, first described by Hans Christian Ørsted in 1820. They were the first instruments used to detect and measure small amounts of electric currents. André-Marie Ampère, who gave mathematical expression to Ørsted's discovery and named the instrument after the Italian electricity researcher Luigi Galvani, who in 1791 discovered the principle of the frog galvanoscope – that electric current would make the legs of a dead frog jerk.

Sensitive galvanometers have been essential for the development of science and technology in many fields. For example, they enabled long range communication through submarine cables, such as the earliest Transatlantic telegraph cables, and were essential to discovering the electrical activity of the heart and brain, by their fine measurements of current.

Galvanometers also had widespread use as the visualising part in other kinds of analog meters, for example in light meters, VU meters, etc., where they were used to measure and display the output of other sensors. Today the main type of galvanometer mechanism, still in use, is the moving coil, D'Arsonval/Weston type.

Hippolyte Pixii

Hippolyte Pixii (1808–1835) was an instrument maker from Paris, France. In 1832 he built an early form of alternating current electrical generator, based on the principle of electromagnetic induction discovered by Michael Faraday. Pixii's device was a spinning magnet, operated by a hand crank, where the north and south poles passed over a coil with an iron core. A current pulse was produced each time a pole passed over the coil. He also found that the current direction changed when the north pole passed over the coil after the south pole. Later, acting on a suggestion by André-Marie Ampère, other results were obtained by introducing a commutator which produced a pulsating direct current. At that time direct current was preferable to alternating current. Although Pixii did not fully understand electromagnetic induction, his device led to more sophisticated devices being constructed.

Jean-Jacques Ampère

Jean-Jacques Ampère (12 August 1800 – 27 March 1864) was a French philologist and man of letters.

Born in Lyon, he was the only son of the physicist André-Marie Ampère (1775–1836). Jean-Jacques' mother died while he was an infant. (But André-Marie Ampère had a daughter – Albine (1807–1842) – with his second wife.) On his tomb at the cemetery of Montmartre, Paris, he is named Jean-Jacques Antoine Ampère. His father's father was also named Jean-Jacques Ampère (executed in Lyon, 1793).

He studied the folk songs and popular poetry of the Scandinavian countries in an extended tour in northern Europe. Returning to France in 1830, he delivered a series of lectures on Scandinavian and early German poetry at the Athenaeum in Marseille. The first of these was printed as De l'Histoire de la poésie (1830), and was practically the first introduction of the French public to the Scandinavian and German epics.

Moving to Paris, he taught at the Sorbonne, and became professor of the history of French literature at the Collège de France. A journey in northern Africa (1841) was followed by a tour in Greece and Italy, in company with Prosper Mérimée, Jean de Witte and Charles Lenormant. This bore fruit in his Voyage dantesque (printed in his Grèce, Rome et Dante, 1848), which did much to popularize the study of Dante in France.

In 1848 he became a member of the Académie française, and in 1851 he visited America. From this time he was occupied with his chief work, L'Histoire romaine à Rome (4 vols., 1861–1864), until his death at Pau.

The Correspondence et souvenirs (2 vols.) of A-M and J-J Ampère (1805–1854) was published in 1875. Notices of J-J Ampère are to be found in Sainte-Beuve's Portraits littéraires, vol. iv., and Nouveaux Lundis, vol. xiii.; in P Mérimée's Portraits historiques et littéraires (2nd ed., 1875); and in Alexis de Tocqueville's Recollections (1893).

List of lay Catholic scientists

Many Catholics have made significant contributions to the development of science and mathematics from the Middle Ages to today. These scientists include Galileo Galilei, René Descartes, Louis Pasteur, Blaise Pascal, André-Marie Ampère, Charles-Augustin de Coulomb, Pierre de Fermat, Antoine Laurent Lavoisier, Alessandro Volta, Augustin-Louis Cauchy, Pierre Duhem, Jean-Baptiste Dumas, Alois Alzheimer, Georgius Agricola, and Christian Doppler.

For additional Catholic scientists, see the List of Catholic churchmen-scientists.

List of École Polytechnique faculty

This list of École Polytechnique faculty includes current and former professors of École Polytechnique, a French scientific higher education institution established during the French Revolution in 1794 in Paris and moved to Palaiseau in 1976. In 2007, École Polytechnique became a founding member of the ParisTech group of leading Paris-area engineering schools.

Magnetosphere chronology

The following is a chronology of discoveries concerning the magnetosphere.

1600 - William Gilbert in London suggests the Earth is a giant magnet.

1741 - Hiorter and Anders Celsius note that the polar aurora is accompanied by a disturbance of the magnetic needle.

1820 - Hans Christian Ørsted discovers electric currents create magnetic effects. André-Marie Ampère deduces that magnetism is basically the force between electric currents.

1843 - Samuel Schwabe, a German amateur astronomer, shows the existence of an 11-year sunspot cycle.

1859 - Richard Carrington in England observes a solar flare; 17 hours later a large magnetic storm begins.

1892 - George Ellery Hale introduces the spectroheliograph, observing the Sun in hydrogen light from the chromosphere, a sensitive way of detecting flares. He confirms the connection between flares and magnetic storms.

1900-3 - Kristian Birkeland experiments with beams of electrons aimed at a magnetized sphere ("terrella") in a vacuum chamber. The electrons hit near the magnetic poles, leading him to propose that the polar aurora is created by electron beams from the Sun. Birkeland also observes magnetic disturbances associated with the aurora, suggesting to him that localized "polar magnetic storms" exist in the auroral zone.

1902 - Marconi successfully sends radio signals across the Atlantic Ocean. Oliver Heaviside suggests that the radio waves found their way around the curving Earth because they were reflected from electrically conducting layer at the top of the atmosphere.

1926 - Gregory Breit and Merle Tuve measure the distance to the conducting layer—which R. Watson-Watt proposes naming "ionosphere"—by measuring the time needed for a radio signal to bounce back.

1930-1 - After Birkeland's "electron beam" theory is disproved, Sydney Chapman and Vincent Ferraro in England propose that magnetic storms are caused when plasma clouds ejected from the Sun envelope the Earth.

1949 - A sudden increase in cosmic rays is traced to an eruption on the Sun. A much larger "flare event" occurs on February 23, 1956.

1953 - Owen Storey proves that "whistler" radio waves are produced by lightning and are often guided through distant space along field lines of the Earth's magnetic field.

1954 - Meredith, Gottlieb and Van Allen use a rocket in the auroral zone to detect radiation from the aurora.

1957 - Sputnik 1 launched by the Soviet Union, the first artificial satellite.

1958 - Explorer 1, built by Van Allen and his Iowa group and launched by the US January 31, observes the radiation belt. Explorer 3, launched in March, comes up with the first clear evidence for its existence.

1958 - Eugene Parker (Chicago) proposes the theory of the solar wind.

1958 - Pioneer 3 observes the outer radiation belt.

1958 - Project Argus, 3 small nuclear bombs above the south Atlantic Ocean, creates artificial radiation belts, lasting about 2 weeks. The project also creates artificial aurora.

1959 - Thomas Gold proposes the name "Magnetosphere"

1961 - James Dungey in Britain proposes a reconnection mechanism for transmitting solar wind energy to the magnetosphere by direct magnetic linkage between the two.

1961 - Ian Axford and Colin Hines (Canada) raise an alternative possibility, of energization by fluid friction at the boundary between the two.

1961 - The magnetopause, boundary between magnetosphere and the solar wind, is observed by Explorer 12. The measurements confirm predictions made in 1931 by Chapman and Ferraro.

1962 - In July, a U.S. H-bomb test (Project Starfish) above the central Pacific Ocean creates a radiation belt of high-energy electrons, parts of which remain until 1967. The new belt creates aurora at Samoa and unexpectedly knocks out 3 artificial satellites.

1964 - IMP-1 (Interplanetary Monitoring Platform 1) reports a large bow shock formed in the solar wind ahead of the magnetosphere, and a long magnetic tail on the night side of the Earth.

1964 - Syun-Ichi Akasofu (Japan-U.S.) and Sydney Chapman revive and expand Birkeland's notion of a "polar magnetic storm", now named "magnetic substorm."

1971 - Ionospheric O+ ions found among energetic particles trapped in the Earth's magnetic field, evidence that O+ ions are pulled out of the ionosphere and accelerated

1972 - Observations of the diffuse aurora are reported, made by the Canadian spacecraft Isis 2.

1974 - A large-scale pattern of "Birkeland currents" between space and the auroral zone traced by Alfred Zmuda and Jim Armstrong, using the Navy's "Triad" satellite.

1974 - David Evans presents evidence that auroral electrons are accelerated within 8000 km or so of Earth.

1977 - The S3-3 satellite of the U.S. Air Force observes the upward acceleration of O+ ions, related to the downward acceleration of electrons in the polar aurora.

1981 - High resolution auroral images are obtained by the Dynamics Explorer satellite.

1983 - ISEE-3 (International Sun-Earth Explorer 3) explores the distant magnetotail, observes that the distant tail plasma flows (past about 70 RE) away from Earth.

1985 - An "artificial comet" is produced by a cloud of barium ions, released by the German IRM (Ion Release Module) satellite. Meanwhile, another AMPTE spacecraft, CCE (Charge Composition Explorer) observes mass and energy distribution in the ring current, including its peak energies around 65 keV.

Monge–Ampère equation

In mathematics, a (real) Monge–Ampère equation is a nonlinear second-order partial differential equation of special kind. A second-order equation for the unknown function u of two variables x,y is of Monge–Ampère type if it is linear in the determinant of the Hessian matrix of u and in the second-order partial derivatives of u. The independent variables (x,y) vary over a given domain D of R2. The term also applies to analogous equations with n independent variables. The most complete results so far have been obtained when the equation is elliptic.

Monge–Ampère equations frequently arise in differential geometry, for example, in the Weyl and Minkowski problems in differential geometry of surfaces. They were first studied by Gaspard Monge in 1784 and later by André-Marie Ampère in 1820. Important results in the theory of Monge–Ampère equations have been obtained by Sergei Bernstein, Aleksei Pogorelov, Charles Fefferman, and Louis Nirenberg.

Place Ampère

The Place Ampère is a pedestrian square located in the Ainay square, in the 2nd arrondissement of Lyon. It is nearly the middle of the rue Victor Hugo and is served by the metro station Ampère - Victor Hugo.

SI base unit

The International System of Units (SI = Systeme Internationale) defines seven units of measure as a basic set from which all other SI units can be derived. The SI base units and their physical quantities are the meter for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the candela for luminous intensity, and the mole for amount of substance.

The SI base units form a set of mutually independent dimensions as required by dimensional analysis commonly employed in science and technology.

The names and symbols of SI base units are written in lowercase, except the symbols of those named after a person, which are written with an initial capital letter. For example, the metre (US English: meter) has the symbol m, but the kelvin has symbol K, because it is named after Lord Kelvin and the ampere with symbol A is named after André-Marie Ampère.

Several other units, such as the litre (US English: liter), are formally not part of the SI, but are accepted for use with SI.

USS Ampere

USS Ampere (PCE-919/AM-359/YDG-11/ADG-11) was originally planned as a PCE-905-class patrol craft for the United States Navy, PCE-919, and laid down as an Admirable-class minesweeper, named Drake, for the male duck. Before she was commissioned, her name was cancelled and she was reclassified as a District Degaussing Vessel. She was later renamed Ampere, after the ampere, a unit of electric current, which takes its name from the French physicist André-Marie Ampère.

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