André-Marie Ampère

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André-Marie Ampère

André-Marie Ampère (born January 20, 1775 in Lyon , France , † June 10, 1836 in Marseille ) was a French physicist and mathematician . He was the pre-eminent experimenter and theorist of early electrodynamics . The international unit of amperage is named after him.


Parents' home in Poleymieux , now a museum

Ampère was the son of Jean-Jacques Ampère and his wife Jeanne-Antoinette de Sarcey. He was noticed at an early age as an inquisitive boy and because of his good memory. His father was an admirer of Jean-Jacques Rousseau and raised Ampère after his Emile , his mother ensured his religious roots in Catholicism. As a youth, Ampère read Buffon's natural history and systematically the 35 volumes of the encyclopedia by Denis Diderot and Jean d'Alembert and learned Greek, Latin and Italian. His father was executed as a Girondist in 1793 after the fall of Lyon (during the French Revolution ) (as a justice of the peace he had previously arrested and executed a leading Jacobin in Lyon, Joseph Chalier), which sparked a deep crisis at Ampère. At the age of eighteen he studied the textbooks of the Swiss mathematician Leonhard Euler and the classical mechanics of Joseph-Louis Lagrange . At the same age he developed a planned language that he viewed as a peace-promoting tool. He also turned to botany , metaphysics and psychology before studying mathematics and physics . After parental fortunes melted, he gave private tuition, especially math. But his contacts with the outside world were minimal.

In 1796 he met Julie Carron, whom he married in 1799. She was a little older and came from a respected middle-class family in a neighboring town of Ampère. Although they came from similar social backgrounds, Ampère was not a good match and he campaigned for them long and hard, which is documented in his diary. In 1800 their son Jean-Jacques Ampère was born, who became a well-known historian, philologist and writer. In 1802 he became a teacher of physics and chemistry at the École centrale in Bourg-en-Bresse . In the same year Ampère wrote a mathematical work on a probabilistic aspect of games of chance, namely the question of the probability of the gambler's ruin if a fixed fraction of his capital is constantly used. The work made him known among scientists in Paris. Soon after, he wrote a thesis on theoretical mechanics and a treatise on partial differential equations , which in 1814 earned him membership in the French Academy of Sciences (then Institut Impèrial).

The four years of his first marriage were the happiest of his life. In 1803, after four years of marriage, his wife died, who had never fully recovered from the birth of their son. Ampère was deeply hit and moved to Paris in 1804 . His interest in mathematics waned and he became increasingly concerned with the writings of Kant , general philosophy of science, and chemistry. Ampère was a tutor for mathematics at the École polytechnique in Paris , but this soon bored him. In 1808 he became inspector general of the universities, which he remained until his death for a few years in the 1820s. From 1819 he also taught philosophy at the historical-philosophical faculty of the Sorbonne and in 1820 he became assistant professor in astronomy. In 1824 he received the chair for experimental physics at the Collège de France .

In August 1806 he married Jeanne-Françoise Potot (1778–1866) in Paris, but the marriage was unhappy and soon divorced. The daughter Albine (1807–1842) comes from this marriage. He now had to look after the two children from the two marriages alone. Both later worried him, his daughter was married to an irascible and often drunk army officer and his son fell under the influence of Madame Recamier .

In 1836, Ampère died of pneumonia on an inspection tour in Marseille at the age of 61. He is buried in Paris on the Cimetière de Montmartre .


Ampère drew up Avogadro's law three years after Amedeo Avogadro independently of him . He was also open to the work of Humphry Davy , which shook the foundations of the French school of chemistry ( Antoine Laurent de Lavoisier ): for Lavoisier, oxygen was the carrier of the acid principle, but after Davy's discovery of sodium and potassium, it was found in strong bases . This also solved the riddle of the green gas (chlorine gas) in the decomposition of hydrochloric acid; Ampère like Davy suspected that it could be a new element (chlorine) (while according to the Lavoisier theory, oxygen was assumed to be a component). Since Ampère had neither the time nor the means to pursue this further, Davy is considered to be its discoverer. Later (1813) Ampère recognized the relationship between the iodine, which had just been discovered in seaweed, and chlorine, but in the public recognition as a discovery of a new element, others came before it. He tried to derive the chemical affinity of molecules, which consist of point-like atoms, from the geometry of geometrical bodies (for example tetrahedron, octahedron or cubes). For example, with oxygen, nitrogen and hydrogen, four molecules formed a tetrahedron, with chlorine eight molecules formed an octahedron (according to Ampère); Connections of elements could only exist if they formed regular polyhedra (which was not possible with tetrahedron and octahedron, but two tetrahedra with one octahedron to one dodecahedron). Ampère's more speculative work on chemistry, however, found little interest from other scholars of his time.

His most important work began in 1820 and made him the founder of electrodynamics. In 1827 Ampère's health deteriorated and he turned from electrodynamics to other areas (philosophy, logic, anatomy, crystal optics, botany). In philosophy he was influenced by Kant and was even one of the first in France to seriously receive his work. For Ampère, this was an alternative to the sensualistic epistemology of Étienne Bonnot de Condillac, which was then prevalent in France . At the same time, Ampère rejected the doctrine of space and time as a priori view of Kant, but retained his distinction between phenomena and noumenon . He partly followed the teaching of his friend Maine de Biran in demonstrating the existence of an independent material world, of God and soul. Ampère advocated a hypothetical-deductive method of gaining scientific knowledge: the naturalist creates a hypothesis and asks himself which experiments must be undertaken to support or falsify the theory. He proceeded pragmatically: Hypotheses could be introduced freely, the only important thing was how successful they were in explaining nature. Later he dealt with the natural philosophy and the pre-established harmony of Gottfried Wilhelm Leibniz . Since man's thinking is an image of God's thinking and God created the universe, according to Leibniz the human spirit should be able to understand the universe in pure acts of thought: His and the laws of thought should therefore correspond to one another. The unity of science should be the reflection of the divine spirit. Ampère strove to classify all sciences and published a book on it in 1834. Some of the 64 disciplines had also been newly introduced by him, such as technical kinematics and cybernetics.

In mathematics, the Monge-Ampèresche equation is named after him, a nonlinear partial differential equation of the second order, which is used in differential geometry and in transport problems and which Ampère dealt with around 1820 (and Gaspard Monge before that ).

Work on electrodynamics

In the early autumn of 1820 Ampère, who was now 45 years old and whose previous scientific work would only have appeared as footnotes in textbooks, became aware of Hans Christian Ørsted's attempts to deflect a magnetic needle by means of an electric current through François Arago . Ampère repeated the experiment and realized that Ørsted had ignored the deflection of the magnet by the earth's magnetic field. With an improved experimental set-up, Ampère was able to determine that the magnetic needle was always perpendicular to the current-carrying conductor. Ampère now assumed as a model hypothesis that every magnetism has its cause in electrical currents and currents generate magnetic fields. He checked his hypothesis - hypothetically-deductive - between September 18 and November 2, 1820 and was able to prove in successive experiments that two current-carrying conductors exert an attractive force on each other if the direction of the electric current is the same in both conductors , and that they are one Exert repulsive force on each other when the current direction is opposite. Ampère constructed a device to measure the current, which he called galvanometer (independently of Ampère, Johann Schweigger in Germany did this ). Ampère refined his hypothesis by assuming that every magnet contains many molecules, each of which creates a small circular current (so-called Ampère molecular currents to explain magnetism). He realized that flowing electricity is the real cause of magnetism.

In 1822 Ampère dealt with the force between two close-together current-carrying conductors. He was able to show that this force is proportional to the reciprocal of the distance. In the mathematical treatment of these phenomena, he took Isaac Newton 's law of gravitation (as the point-force law) as a model. However, since the current has to be treated as a directed quantity and the current strength contains the time as a new quantity, the Ampère model has only limited validity.

Ampère explained the concept of electrical voltage and electrical current and established the direction of the current.

In addition to the founding of electrodynamics , Ampère recognized the principle of electrical telegraphy (proposal of an electromagnetic telegraph with Jacques Babinet in 1822), but this was not very practical over long distances. An electrical telegraph was first realized in 1833 by Carl Friedrich Gauß and Wilhelm Eduard Weber in Göttingen .

Ampère believed that the earth's magnetic field is triggered by strong electrical currents flowing from east to west in the earth's crust.

Grave of André-Marie Ampère and (right:) son Jean-Jacques Antoine Ampère in Montmartre Cemetery , Paris .

James Clerk Maxwell counted Ampère's work on electrodynamics in his Treatise on electricity and magnetism among the most brilliant deeds ever accomplished in science . His writing is perfect in form, unattainable in the precision of expression and its balance consists of a formula from which one can derive all the phenomena offered by electricity, and which will remain in all times as the cardinal formula of electrodynamics . At the same time, Maxwell suspected that the Newton of Electricity , as Maxwell calls him, did not get his theory solely from inductive conclusions (from the experiment), but followed a different path and then all traces from the scaffolding that served him to erect his building removed .


Ampère's character was characterized by great kindness and sensitivity. But he also tended to exuberance and melancholy, reinforced by several blows of fate, to indecision and a certain helplessness in everyday things and his absent-mindedness was proverbial. He was very persistent in his scientific work, but generally did not follow a systematic plan, but followed a flash of inspiration feverishly until it was worked out. Ampère was prone to metaphysical speculation and was deeply religious.


Postage stamp from the Deutsche Post of the GDR from the series Important Personalities (1975)

In honor of Ampère, the SI unit of electrical current " Ampere " ( unit symbol A) was named. He was honored by being named on the Eiffel Tower . A mountain on the moon, the Mons Ampère , has been named after him since 1935 . In 1814 he became a member of the Académie des Sciences in Paris and in 1822 a Fellow of the Royal Society of Edinburgh . From 1827 he was a corresponding member of the Prussian Academy of Sciences and a foreign member of the Royal Society . In December 1830 he was elected an honorary member of the Russian Academy of Sciences in St. Petersburg .

The plant genus Amperea is named after him . named from the family of milkweed plants (Euphorbiaceae).


Essai on the Philosophy of Science
  • Considerations sur la théorie mathématique du jeu , Perisse, Lyon Paris 1802, read online in the Internet archive
  • André-Marie Ampère: Recueil d'observations électro-dynamiques . contenant diverse mémoires, notices, extraits de lettres ou d'ouvrages périodiques sur les sciences, relatifs a l'action mutuelle de deux courans électriques, à celle qui existe entre un courant électrique et un aimant ou le globe terrestre, et à celle de deux aimans l'un sur l'autre. Chez Crochard, 1822 (French, read online in Google Book Search [accessed September 26, 2010]).
  • André-Marie Ampère, Babinet (Jacques, M.): Exposé des nouvelles découvertes sur l'électricité et le magneétisme . Chez Méquignon-Marvis, 1822 ( read online in Google Book Search [accessed September 26, 2010]).
  • André-Marie Ampère: Description d'un appareil électro-dynamique . Chez Crochard… et Bachelie, 1824 ( read online in Google Book Search [accessed September 26, 2010]).
  • André-Marie Ampère: Théorie des phénomènes électro-dynamiques, uniquement déduite de l'expérience . Méquignon-Marvis, 1826 ( read online in the Google book search [accessed September 26, 2010]).
    • André-Marie Ampère: Théorie mathématique des phénomènes électro-dynamiques: uniquement déduite de l'expérience . New edition edition. A. Hermann, 1883 ( read online in the Internet archive [accessed on September 26, 2010]).
  • André-Marie Ampère: Essai sur la philosophie des sciences, ou, Exposition analytique d'une classification naturelle de toutes les connaissances humaines . Chez Bachelier, 1834 ( read online in Google Book Search [accessed September 26, 2010]).
    • André-Marie Ampère: Essai sur la philosophie des sciences . tape 1 . Chez Bachelier, 1834 ( read online in Google Book Search [accessed September 26, 2010]).
    • André-Marie Ampère: Essai sur la philosophie des sciences . tape 2 . Bachelier, 1843 ( read online in Google Book Search [accessed September 26, 2010]).


  • Henriette Cheuvreux (Ed.): Journal et correspondance de André-Marie Ampère. Recueillis par Mme HC , J. Hetzel, Paris 1872, read online in the Internet archive
    • André-Marie Ampère. Correspondance et souvenirs (de 1793 a 1805). Recueillis par Madame HC , J. Hetzel, Paris 1877 (7th edition), read online in the Internet archive
    • André-Marie Ampère. Journal et correspondance (1793 à 1805). Recueillis par Madame HC , Paul Ollendorff, Paris 1893 (9th edition), read online in the Internet archive
  • Henriette Cheuvreux (eds.): André-Marie Ampère et Jean-Jacques Ampère. Correspondance et souvenirs (de 1805 a 1864). Recueillis par Madame HC , J. Hetzel, Paris 1875 (in the Internet archive: volumes 1 , 2 )
  • Correspondance du Grand Ampère , 3 volumes, Paris 1936 to 1943


  • François Arago : Ampère in: Franz Aragos Complete Works, Volume 2, Leipzig 1854, pp. 3–94
  • James R. Hofmann: André-Marie Ampère , Cambridge University Press 1996
  • Christine Blondel: A.-M. Ampere et la creation de l'electrodynamique 1820–1827 , Paris, Bibliotheque Nationale 1982
  • Louis de Broglie : André Marie Ampère , in: Louis de Broglie, Elementarteilchen, Hamburg 1954, pp. 245–269
  • Adolphe Quételet : Notice sur M. Ampère, ne à Lyon en 1775, mort à Marseille, le 10 June 1836 , Annuaire de l'Académie royale des sciences et belles-lettres de Bruxelles 3, 1837, pp. 134-136 (obituary; French; read online in Google Book Search)
  • Charles-Augustin Sainte-Beuve : Ampère. Sa jeunesse, ses études diverse, ses idées métaphysiques, etc. (obituary; French), Revue des deux mondes 9, 1837, pp. 389–422 ( read online in the Google book search); Revue du Lyonnais 5, 1837, pp. 332–372 ( read online in the Google book search)
  • Célébration à Lyon du Centenaire de la mort d'André-Marie Ampère 1836–1936, 2 volumes, Lyon 1936
  • Jules Barthélemy-Saint-Hilaire : Philosophy des deux Ampère , Didier, Paris 1866 ( read online in Google book search)
  • Claude-Alphonse Valson: La vie et les travaux d'André-Marie Ampère , Vitte et Perrussel, Lyon 1886 (French), read online in the internet archive
  • Tomáš Borec: Good afternoon, Mr. Ampère. Interesting and entertaining facts about famous scientists and units of measurement named after them , Harri Deutsch, Thun Frankfurt am Main 1979, ISBN 3-87144-372-7 (translation from Slovak, original title Dobrý deň, pán Ampère )
  • L. Pearce Williams: André-Marie Ampère as a physicist and natural philosopher , Spectrum of Science, March 1989, pp. 114–124
  • L. Pearce Williams: Ampère, André-Marie . In: Charles Coulston Gillispie (Ed.): Dictionary of Scientific Biography . tape 1 : Pierre Abailard - LS Berg . Charles Scribner's Sons, New York 1970, p. 139-147 .
  • Ernst Schwenk: measure people. From Ampère and Becquerel to Watt and Weber. Who gave the name to the international units of measurement , Oesch, Zurich 2003, ISBN 3-0350-2005-1
  • Friedrich Steinle : Exploratory Experiments. Ampère, Faraday and the origins of electrodynamics , Franz Steiner, Berlin 2005, ISBN 3-515-08185-2
  • K. Jäger, F. Heilbronner (ed.): Lexikon der Elektrotechniker , VDE Verlag, 2nd edition from 2010, Berlin / Offenbach, ISBN 978-3-8007-2903-6 , pp. 20-21
  • P. Volkmann: Technology pioneers: namesake of units of physical units , VDE Verlag, Berlin / Offenbach 1990, ISBN 3-8007-1563-5 , pp. 19-22
  • Isaac Asimov: Biographical Encyclopedia of Natural Sciences and Technology , Herder, Freiburg / Basel / Vienna 1974, ISBN 3-451-16718-2 , pp. 203-204

Individual evidence

  1. ^ Dictionary of Scientific Biography, Article Ampère
  2. Wolfgang Schreier (Ed.), Biographies of important physicists, People and Knowledge 1984, p. 135
  3. ^ Maxwell, Textbook of Electricity and Magnetism , Volume 2, Berlin, Julius Springer 1883, p. 217
  4. ^ Dictionary of Scientific Biography, Article Ampère
  5. Wolfgang Schreier (Ed.), Biographies of important physicists, People and Knowledge 1984, p. 135
  6. ^ List of members since 1666: Letter A. Académie des sciences, accessed on October 1, 2019 (French).
  7. ^ Members of the previous academies. André-Marie Ampère. Berlin-Brandenburg Academy of Sciences , accessed on February 15, 2015 .
  8. entry on ampere; Andre-Marie (1775-1836) in the Archives of the Royal Society , London
  9. ^ Foreign members of the Russian Academy of Sciences since 1724: Ampère, André-Marie. Russian Academy of Sciences, accessed October 1, 2019 (Russian).
  10. Lotte Burkhardt: Directory of eponymous plant names - Extended Edition. Part I and II. Botanic Garden and Botanical Museum Berlin , Freie Universität Berlin , Berlin 2018, ISBN 978-3-946292-26-5 doi: 10.3372 / epolist2018 .

Web links

Commons : André-Marie Ampère  - Album with pictures, videos and audio files