André-Marie Ampère (UK: , US: ; French: [ɑ̃dʁe maʁi ɑ̃pɛʁ]; 20 January 1775 – 10 June 1836), a French physicist and mathematician, is recognized as a foundational figure in the science of classical electromagnetism, a field he termed electrodynamics. His significant contributions also extended to chemistry and philosophy. Furthermore, he is credited with inventing several practical applications, including the solenoid (a term he originated) and the electrical telegraph. Despite being largely self-taught, Ampère held membership in the French Academy of Sciences and served as a professor at both the École Polytechnique and the Collège de France.
André-Marie Ampère (UK: , US: ; French: [ɑ̃dʁemaʁiɑ̃pɛʁ]; 20 January 1775 – 10 June 1836) 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 made also important contributions in chemistry and philosophy. He is also the inventor of numerous applications, such as the solenoid (a term coined by him) and the electrical telegraph. As an autodidact, Ampère was a member of the French Academy of Sciences and professor at the École polytechnique and the Collège de France.
The ampere (A), the SI unit for electric current, bears his name. His name is also among the 72 inscribed on the Eiffel Tower. The English term kinematic originates from his French coinage, cinématique, which he derived from the Greek word κίνημα kinema, meaning 'movement' or 'motion,' itself stemming from κινεῖν kinein, 'to move.'
Biography
Early Life
André-Marie Ampère was born in Lyon on January 20, 1775, to Jean-Jacques Ampère, a prosperous businessman, and Jeanne Antoinette Desutières-Sarcey Ampère, amidst the flourishing French Enlightenment. His childhood and adolescence were spent at the family estate in Poleymieux-au-Mont-d'Or, near Lyon, a location now home to the Ampère Museum, which commemorates his life and the evolution of electricity. Jean-Jacques Ampère, a successful merchant, admired Jean-Jacques Rousseau's philosophy, and Rousseau's educational theories, detailed in his treatise Émile, formed the foundation of Ampère's early instruction. Rousseau advocated for young boys to forgo formal schooling in favor of a 'direct education from nature.' Ampère's father implemented this principle by enabling his son to pursue self-education within their extensive library. Consequently, seminal works of the French Enlightenment, including Georges-Louis Leclerc, comte de Buffon's Histoire naturelle, générale et particulière (initiated in 1749) and Denis Diderot and Jean le Rond d'Alembert's Encyclopédie (with volumes published between 1751 and 1772), served as Ampère's primary educational resources. Nevertheless, the young Ampère eventually resumed Latin studies, which facilitated his mastery of the works by Leonhard Euler and Daniel Bernoulli.
French Revolution
Furthermore, at the age of 12, Ampère leveraged his access to contemporary literature to commence self-instruction in advanced mathematics. Ampère later asserted that by eighteen, his knowledge of mathematics and science was as extensive as it would ever be; however, as a polymath, his intellectual pursuits encompassed history, travel, poetry, philosophy, and the natural sciences. Influenced by his devout Catholic mother, Ampère was introduced to the Catholic faith concurrently with his exposure to Enlightenment scientific thought. The French Revolution (1789–1799), which commenced during his formative years, significantly impacted Ampère's family: his father was appointed to public service by the nascent revolutionary government, serving as a local judge (juge de paix) in a small town near Lyon. However, when the Jacobin faction assumed control of the revolutionary government in 1792, Jean-Jacques Ampère opposed the shifting political landscape and was subsequently guillotined on November 24, 1793, during the Jacobin purges of that era.
Ampère met Julie Carron in 1796, and they married in 1799. In 1799, Ampère secured his first permanent position as a mathematics teacher, providing the financial stability necessary for his marriage to Carron and the birth of their first child, Jean-Jacques (named after his father), the following year. (Jean-Jacques Ampère later gained recognition as a distinguished scholar of languages.) Ampère's professional development coincided with France's transition to the Napoleonic regime, presenting the young father and educator with new avenues for advancement within the technocratic framework favored by the new French First Consul. In 1802, Ampère received an appointment as a professor of physics and chemistry at the École Centrale in Bourg-en-Bresse, necessitating his departure from his ailing wife and infant son in Lyon. During his tenure in Bourg, he dedicated himself to mathematical research, culminating in Considérations sur la théorie mathématique du jeu (1802; 'Considerations on the Mathematical Theory of Games'), a treatise on mathematical probability submitted to the Paris Academy of Sciences in 1803.
Teaching Career
Following his wife's death in July 1803, Ampère relocated to Paris, securing a tutoring position at the newly established École Polytechnique in 1804. Despite lacking formal credentials, he was promoted to professor of mathematics at the institution by 1809. His tenure at this school extended until 1828, during which he also delivered lectures in philosophy (1819) and astronomy (1820) at the University of Paris. In 1824, Ampère achieved election to the esteemed chair of experimental physics at the Collège de France. Earlier, in 1814, he received an invitation to join the mathematicians' class within the nascent Institut Impérial, which served as the overarching body for the reorganized state Academy of Sciences.
Prior to his election to the academy, Ampère pursued a wide range of scientific investigations, authoring papers and exploring subjects spanning mathematics, philosophy, chemistry, and astronomy, a breadth of inquiry typical among prominent scientific thinkers of that era. Ampère reportedly identified three pivotal moments in his life by the age of eighteen: his First Communion, his engagement with Antoine Leonard Thomas's "Eulogy of Descartes," and the storming of the Bastille. On the day of his wife's passing, he composed two verses from the Psalms and a prayer: 'O Lord, God of Mercy, unite me in Heaven with those whom you have permitted me to love on earth.' During periods of hardship, he sought solace in reading the Bible and the writings of the Church Fathers.
As a lay Catholic, Ampère temporarily welcomed the young student Frédéric Ozanam (1813–1853) into his household. Ozanam later co-founded the Conference of Charity, subsequently known as the Society of Saint Vincent de Paul, and was beatified by Pope John Paul II in 1998. Through Ampère's connections, Ozanam gained access to influential figures within the neo-Catholic movement, including François-René de Chateaubriand, Jean-Baptiste Henri Lacordaire, and Charles Forbes René de Montalembert.
Research in Electromagnetism
In September 1820, François Arago, a colleague and future eulogist of Ampère, presented to the French Academy of Sciences the remarkable discovery by Danish physicist Hans Christian Ørsted: that an electric current in proximity to a magnetic needle causes its deflection. Prompted by this revelation, Ampère commenced the formulation of a mathematical and physical theory to elucidate the connection between electricity and magnetism. Building upon Ørsted's experimental findings, Ampère demonstrated that two parallel wires conducting electric currents either attract or repel each other, contingent on whether the currents flow in the same or opposing directions, respectively; this observation established the groundwork for electrodynamics. He further employed mathematical principles to generalize physical laws derived from these experimental outcomes. Foremost among these was the principle subsequently known as Ampère's Law, which posits that the reciprocal force between two segments of current-carrying wire is directly proportional to their lengths and the magnitudes of their currents. Ampère extended this principle to magnetism, thereby illustrating the congruence between his law and French physicist Charles Augustin de Coulomb's law of electric interaction. His profound dedication to and proficiency in experimental methodologies firmly situated his scientific contributions within the burgeoning domain of experimental physics.
Furthermore, Ampère advanced a physical interpretation of the electromagnetic relationship, positing the existence of an "electrodynamic molecule"—a precursor to the concept of the electron—which he theorized as the fundamental constituent of both electricity and magnetism. Leveraging this physical framework for electromagnetic motion, Ampère formulated an explanation of electromagnetic phenomena that was both empirically verifiable and mathematically prognostic. Nearly a century later, in 1915, Albert Einstein, in collaboration with Wander Johannes de Haas, provided experimental validation for Ampère's hypothesis through the Einstein–de Haas effect. In 1826, Ampère released his seminal work, 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). This publication not only introduced the term for his novel scientific discipline, electrodynamics, but also became universally recognized as its foundational treatise.
Ampère received significant international recognition, being elected a Foreign Member of the Royal Society in 1827 and a foreign member of the Royal Swedish Academy of Science in 1828. Perhaps his most notable commendation came from James Clerk Maxwell, who, in his seminal work Treatise on Electricity and Magnetism, famously referred to Ampère as "the Newton of electricity."
Honors
- On October 8, 1825, Ampère was inducted as a Member of the Royal Academy of Science, Letters and Fine Arts of Belgium.
Legacy
Ampère's profound contributions to modern electrical science were formally acknowledged at the 1881 International Exposition of Electricity, where an international convention designated the ampere as a standard unit of electrical measurement. This honor placed his name alongside other foundational units—the coulomb, volt, ohm, watt, and farad—which commemorate his contemporaries: Charles-Augustin de Coulomb (France), Alessandro Volta (Italy), Georg Ohm (Germany), James Watt (Scotland), and Michael Faraday (England), respectively. Furthermore, Ampère's name is among the 72 inscribed on the Eiffel Tower.
Numerous geographical features and institutions bear Ampère's name, including streets, squares, schools, a Lyon metro station, a graphics processing unit microarchitecture, a lunar mountain, an asteroid, and an electric ferry in Norway. Additionally, the town of Ampére in the Brazilian state of Parana is named in his honor.
Publications
- Considérations sur la théorie mathématique du jeu (Considerations on the Mathematical Theory of Games), Perisse, Lyon Paris 1802.
- André-Marie Ampère (1822), Recueil d'observations électro-dynamiques: contenant divers 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 (Collection of Electro-Dynamic Observations: Containing Various Memoirs, Notices, Extracts from Letters or Periodical Works on the Sciences, Relating to the Mutual Action of Two Electric Currents, to that Existing Between an Electric Current and a Magnet or the Terrestrial Globe, and to that of Two Magnets on Each Other) (in French), Chez Crochard, retrieved September 26, 2010André-Marie Ampère; Babinet (Jacques, M.) (1822), Exposé des nouvelles découvertes sur l'électricité et le magnétisme (Exposition of New Discoveries on Electricity and Magnetism) (in German), Chez Méquignon-Marvis, retrieved September 26, 2010André-Marie Ampère (1824), Description d'un appareil électro-dynamique (Description of an Electro-Dynamic Apparatus) (in French), Chez Crochard … et Bachelie, retrieved September 26, 2010André-Marie Ampère (1826), Théorie des phénomènes électro-dynamiques, uniquement déduite de l'expérience (Theory of Electro-Dynamic Phenomena, Uniquely Deduced from Experience) (in French), Méquignon-Marvis, retrieved September 26, 2010André-Marie Ampère (1883), Théorie mathématique des phénomènes électro-dynamiques: uniquement déduite de l'expérience (Mathematical Theory of Electro-Dynamic Phenomena: Uniquely Deduced from Experience) (in French) (2nd ed.), A. Hermann, retrieved September 26, 2010André-Marie Ampère (1834), Essai sur la philosophie des sciences, ou, Exposition analytique d'une classification naturelle de toutes les connaissances humaines (Essay on the Philosophy of Sciences, or, Analytical Exposition of a Natural Classification of All Human Knowledge) (in German), Chez Bachelier, retrieved September 26, 2010André-Marie Ampère (1834), Essai sur la philosophie des sciences (Essay on the Philosophy of Sciences) (in German), vol. Bd. 1, Chez Bachelier, retrieved September 26, 2010André-Marie Ampère (1843), Essai sur la philosophie des sciences (Essay on the Philosophy of Sciences) (in German), vol. Bd. 2, Bachelier, retrieved September 26, 2010Lisa M. Dolling; Arthur F. Gianelli; Glenn N. Statile, eds. (2003). The Tests of Time: Readings in the Development of Physical Theory. Princeton: Princeton University Press. pp. 157–162. ISBN 978-0691090856.Ampère, André-Marie (2015). André Koch Torres Assis (ed.). Ampère's Electrodynamics: Analysis of the Meaning and Evolution of Ampère's Force Between Current Elements, Together with a Complete Translation of His Masterpiece: Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience (PDF). Translated by J. P. M. C Chaib. Montreal: Apeiron. ISBN 978-1-987980-03-5. Archived (PDF) from the original on October 9, 2022.Ampère, André-Marie (2015). Mathematical Theory of Electrodynamic Phenomena, Uniquely Derived from Experiments. Michael D. Godfrey, Stanford University, (trans.).References
- Williams, L. Pearce (1970). "Ampère, André-Marie." In Dictionary of Scientific Biography, Vol. 1, pp. 139–147. New York: Charles Scribner's Sons. ISBN 978-0-684-10114-9.
- Hofmann, James R. (1995). André-Marie Ampère. Oxford: Blackwell. ISBN 978-0631178491.
- Duhem, Pierre Maurice Marie (9 September 2018). Ampère's Force Law: A Modern Introduction. Translated by Alan Aversa. doi:10.13140/RG.2.2.31100.03206/1 (inactive 21 October 2025). Retrieved 3 July 2019. CS1 maintenance: DOI inactive as of October 2025 (link)
This French-language resource, edited by CNRS, explores Ampère and the history of electricity, featuring his correspondence (full text and critical edition with links to manuscript images, over 1000 letters), an Ampère bibliography, experiments, and 3D simulations.
- Ampère and the history of electricity – a French-language, edited by CNRS, site with Ampère's correspondence (full text and critical edition with links to manuscripts pictures, more than 1000 letters), an Ampère bibliography, experiments, and 3D simulations
- The Ampère Museum, located in Poleymieux-au-Mont-d'or, near Lyon, France, offers a French-language website.
- Ampere's Electrodynamics provides a complete English translation of the Theory of Electrodynamic Phenomena.
- The "Société des Amis d'André-Marie Ampère" is a French society dedicated to preserving the legacy of André-Marie Ampère and managing the Ampère Museum.
- O'Connor, John J.; Robertson, Edmund F., "André-Marie Ampère", MacTutor History of Mathematics Archive, University of St Andrews.
- An entry on André Marie Ampère is available in the Catholic Encyclopedia.