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'''André-Marie Ampère''' (Lyons 20 January, 1775  – Marseilles 10 June, 1836) was a French physicist and mathematician. His most important contribution was [[Ampere's law]],  which describes the relation between electric current and magnetic field. The unit of electric current [[Ampere (unit)|ampere]] is named after him.
'''André-Marie Ampère''' (Lyons 20 January, 1775  – Marseilles 10 June, 1836) was a French physicist and mathematician. His most important contributions are [[Ampere's law]],  which describes the relation between electric current and magnetic field and [[Ampere's equation]], which gives the force between two current carrying wires. The unit of electric current [[Ampere (unit)|ampere]] is named after him.
==Biography==
==Biography==
André-Marie did not receive a formal education&mdash;he was tutored by his farther&mdash;and was a child prodigy. At the age of thirteen he submitted his first mathematical paper. This work attempted to solve the problem of constructing a line of the same length as an arc of a circle.<ref>A.-M. Ampère, ''Sur la rectification d'un arc quelconque de cercle plus petit que la demi-circonférence'' [On the rectification of an arbitrary arc smaller than half the circumference of a circle], July 8, 1788
André-Marie did not receive a formal education&mdash;he was tutored by his farther&mdash;and was a child prodigy. At the age of thirteen he submitted his first mathematical paper. This work attempted to solve the problem of constructing a line of the same length as an arc of a circle.<ref>A.-M. Ampère, ''Sur la rectification d'un arc quelconque de cercle plus petit que la demi-circonférence'' [On the rectification of an arbitrary arc smaller than half the circumference of a circle], July 8, 1788
</ref> However, the work was refused and André-Marie realized that he had to become better skilled in mathematics. So, he read [[d'Alembert]]'s article on the differential calculus in the [[Encyclopédie]] and undertook a study of works by [[Leonhard Euler]] and the [[Bernouilli]]s (almost all these writings are in Latin). He started to read the 1788 edition of [[Lagrange]]'s ''Mécanique analytique'' and later claimed that he was able to repeat all the calculations in it.
</ref> However, the work was refused and André-Marie realized that he had to become better skilled in mathematics. So, he read [[d'Alembert]]'s article on the differential calculus in the [[Encyclopédie]] and undertook a study of works by [[Leonhard Euler]] and the [[Bernoulli]]s (almost all these writings are in Latin). He started to read the 1788 edition of [[Lagrange]]'s ''Mécanique analytique'' and later claimed that he was able to repeat all the calculations in it.


Two years after the [[French Revolution]] of 1789 Ampère's father was beheaded by the [[Jacobin]]s.
Four years after the [[French Revolution]] of 1789 Ampère's father was beheaded by the [[Jacobin]]s.
The effect on André-Marie of his father's death was devastating. He gave up his studies of mathematics and only regained his taste for the sciences after he fell in love with his future wife, Julie Carron.  They married in 1799 and their son Jean-Jacques was born in 1800. In 1802 Ampère was appointed teacher of physics and chemistry in Bourg-en-Bresse at the Bourg École Centrale. This was a difficult time for Ampère since Julie became ill and he had to leave her behind in Lyons. Nowadays Lyons and Bourg are seen as close (Bourg is about 60 km North-East of Lyons), but in the beginning of the nineteenth century travel was difficult. While Ampère was in Bourg he found time to perform research in mathematics. He wrote ''Considérations sur la théorie mathématique du jeu'' [Considerations on the Mathematical Theory of Games] in 1802.  After his wife died in July 1803,  Ampère decided to go to Paris.
The effect on André-Marie of his father's death was devastating. [[François Arago]] relates in his 1839 eulogy of Ampère<ref>F. Arago, ''Ampère, biographie'', Lue par extraits en séance publique de l'académie des sciences, August 21 (1839)</ref>,  that during these days André-Marie found consolation in the memory of three peaks in his young life: His first communion, the reading of [[Antoine-Léonard Thomas]]' eulogy of [[René Descartes]], and the taking of the [[Bastille]]. After the execution of his father André-Marie gave up his studies of mathematics and only regained his taste for the sciences after he fell in love with his future wife, Cathérine-Antoinette (Julie) Carron.  They married on August 2, 1799 and their son Jean-Jacques was born in 1800. In 1802 Ampère was appointed teacher of physics and chemistry in Bourg-en-Bresse at l'École Centrale du Département de l'Ain (now the Lycée Lalande). This was a difficult time for Ampère since Julie became ill and he had to leave her behind in Lyons. Nowadays Lyons and Bourg are seen as close (Bourg is about 60 km North-East of Lyons), but in the beginning of the nineteenth century travel was difficult. While Ampère was in Bourg he found time to perform research in mathematics. He wrote ''Considérations sur la théorie mathématique du jeu'' [Considerations on the Mathematical Theory of Games] in 1802.  After his wife died in July 1803,  Ampère decided to go to Paris.


He found a job as répétiteur d'analyse (tutor) in analysis at the École Polytechnique on 20 October 1804, where [[Augustin-Louis Cauchy]] was one of his students. Soon he embarked on a disastrous marriage with a girl named Jenny (1806). Before the birth of their daughter on 6 July 1807, the couple had separated. They were legally divorced in 1808 and Ampère was given custody of their daughter. Notwithstanding these private problems, Ampère was productive in mathematics. Among other things he wrote about variational calculus and about the rest term of the [[Taylor series]] (1806).
He found a job as répétiteur d'analyse (tutor in analysis) at the École Polytechnique on 20 October 1804, where [[Augustin-Louis Cauchy]] was one of his students. Soon he embarked on a disastrous marriage (1806) with a girl called Jenny (Jeanne-Françoise Potot). Before the birth of their daughter Josephine-Albine on 6 July 1807, the couple had separated. They were legally divorced in 1808 and Ampère was given custody of their daughter. Notwithstanding these private problems, Ampère was productive in mathematics. Among other things he wrote about variational calculus and about the rest term of the [[Taylor series]] (1806).


In 1809 he was promoted to professor of mathematical analysis at the École Polytechnique, a post he held until 1828.  In the 1820s Ampère and Cauchy shared the teaching of analysis and both were critized heavily at times, because it was judged that they overloaded the future engineers by too much abstruse mathematics.  
In 1809 Ampère was promoted to professor of mathematical analysis at the École Polytechnique, a post he held until 1828. In 1824 he became also professor at the Collège de France where he was allowed to teach electrodynamics.  In the first half of the 1820s Ampère and Cauchy shared the teaching of analysis at the École Polytechnique and both were criticized heavily at times, because it was judged that both mathematicans overloaded the future engineers by too much abstruse mathematics.  


In 1814 Ampère summarized the functions he had fulfilled thus far together with his mathematical contributions<ref>''Notice des fonctions remplies et des principaux mémoires publiés ou lus à l'Institut et encore inédits, composés par A.M. Ampère''. [Note on the functions fulfilled and the main memorandums published or presented at the Institut and not yet published, composed by A.M. Ampère</ref>,  which he presented to the Academy of Sciences of the  Institut de France in the same year. This was apparently a convincing résumé since it gained him election to the Academy in November 1814, when he defeated his former student Cauchy, who also applied for membership.
In November 1814 Ampère was elected to the Academy (not yet royal) of the Sciences of the Institut de France, when he defeated his former student Cauchy, who also applied for membership. For his denomination he had summarized the functions he had fulfilled thus far together with his mathematical contributions<ref>''Notice des fonctions remplies et des principaux mémoires publiés ou lus à l'Institut et encore inédits, composés par A.M. Ampère''. [Note on the functions fulfilled and the main memorandums published or presented at the Institut and not yet published, composed by A.M. Ampère]</ref>. This was apparently a convincing résumé since it gained him the membership he applied for.


Also in 1814 he made independently the same discovery in chemistry<ref>''Lettre de M. Ampère à M. le comte Berthollet sur la détermination des proportions dans lesquelles les corps se combinent d'après le nombre et la disposition respective des molécules dont les parties intégrantes sont composées,''  [Letter of mr. Ampère to mr. the count Berthollet on the determination of the proportions in which bodies combine according to the number and the suitability of the molecules of which the integral parts are composed] Annales de chimie, vol. '''90''' pp. 43-86 (1814). </ref> that [[Amedeo Avogadro]]  made three years earlier, namely that the same volumes of different gases contain the same number of molecules. His work had the same fate as Avogadro's, their discovery went largely unnoticed by the chemists of the time.
Also in 1814 he made independently the same discovery in chemistry<ref>''Lettre de M. Ampère à M. le comte Berthollet sur la détermination des proportions dans lesquelles les corps se combinent d'après le nombre et la disposition respective des molécules dont les parties intégrantes sont composées,''  [Letter of mr. Ampère to mr. the count Berthollet on the determination of the proportions in which bodies combine according to the number and the suitability of the molecules of which the integral parts are composed] Annales de chimie, vol. '''90''' pp. 43-86 (1814). </ref> that [[Amedeo Avogadro]]  made three years earlier, namely that the same volumes of different gases contain the same number of molecules. His work had the same fate as Avogadro's, their discovery went largely unnoticed by the chemists of the time.


Until 1820 Ampère was not very active on the research front anymore, but on September 11, 1820 when he heard [[François Arago]] speak about [[Hans Christian Oersted‎|Oersted]]'s work, he got fresh inspiration and started the work that made him famous. Oersted had shown that a steady electric current influences the orientation of a compass needle. After a week Ampère  had found experimentally that that two straight, parallel, and current-carrying, wires execute a force on each other. The force is attractive if the currents run in the same direction and repulsive if they run in opposite direction. The magnitude of the force is inversely proportional to the distance between the wires and proportional to the strengths of the currents. Thus Ampère reported at a meeting of the Académie royale des Sciences on September 18, 1820. He was so excited about the phenomenon that he gave talks about it again on September 25 and October 2.<ref>A. M. Ampère, ''Mémoire présenté à l'Académie royale des Sciences, le 2 octobre 1820, où se trouve compris le résumé de ce qui avait été lu à la même Académie les 18 et 25 septembre 1820, sur les effets des courans électriques.'' [Memoir presented at the Royal Academy of Sciences, of October 2, 1820 where one finds a summary of the ones read before
In Parisian scientific circles of the 1810s there was some controversy about the theory of light. [[Augustin-Jean Fresnel]] had rejected [[Isaac Newton|Newton]]'s corpuscular theory and had replaced it  by a wave theory. Biot and Laplace still followed Newton, while [[François Arago]] and Ampère were on Fresnel's side. Doubtedlessly inspired by this discussion, Ampère published on the refraction of light in 1816.
 
From 1814 until 1820 Ampère did not perform the kind of research that would have made it into the annals of the history of science, but on September 11, 1820 when he heard François Arago speak about [[Hans Christian Oersted‎|Oersted]]'s work, he got fresh inspiration and started the work that made him famous. Arago related how Oersted had found that a steady electric current influences the orientation of a compass needle. After a week Ampère  had determined experimentally that that two straight, parallel, and current-carrying, wires execute a force on each other. The magnitude of the force is inversely proportional to the distance between the wires and proportional to the strengths of the currents. This is what Ampère reported at a meeting of the Académie royale des Sciences on September 18, 1820 (see [[Ampere's equation]]). He was so excited about the phenomenon that he gave talks about it again on September 25 and October 2.<ref>A. M. Ampère, ''Mémoire présenté à l'Académie royale des Sciences, le 2 octobre 1820, où se trouve compris le résumé de ce qui avait été lu à la même Académie les 18 et 25 septembre 1820, sur les effets des courans électriques.'' [Memoir presented at the Royal Academy of Sciences, of October 2, 1820 where one finds a summary of the ones read before
the same Academy on September 18 and 25, on the effects of electric currents]. Annales de chimie et de physique,  vol. '''15''', pp. 59-74, and pp.170-218 (1820)</ref>
the same Academy on September 18 and 25, on the effects of electric currents]. Annales de chimie et de physique,  vol. '''15''', pp. 59-74, and pp.170-218 (1820)</ref>


During the following years he continued his researches, both experimentally and theoretically.
During the following years he continued his researches, both experimentally and theoretically.
He built an instrument for measuring electricity that later was developed into the [[galvanometer]].  
He built an instrument for measuring electricity that later was developed into the [[galvanometer]].  
Finally, in 1825 he presented his collected results to the Academy in one of the most celebrated memoirs in the history of natural philosophy.<ref>A. M.  Ampère, ''Mémoire sur une nouvelle expérience électro-dynamique, sur son application à la formule qui représente l'action mutuelle de deux éléments de conducteurs voltaïques, et sur de nouvelles conséquences déduites de cette formule: lu à l'Académie royale des sciences le 12 septembre 1825''.  [Memoir on a new electrodynamic experience, about its application to a formula that gives the mutual action between two Voltaic conductors and about the new consequences deduced from this formula: read at the Royal Academy of Sciences September 12, 1825] Annales de chimie et de physique, 1825, vol. '''29''' and '''30''', pp. 381-404 and p. 29-41.</ref> In 1827 he published a long memoir summarizing his  work on electricity and magnetism over the last seven years.<ref>A.-M. Ampère ''Théorie mathématique des phénomènes électro-dynamiques uniquement déduite de L'expérience'' [Mathematical theory of electrodynamic phenomena, uniquely deduced from experience.]] Mémoires de l'académie royale des sciences de l'institut de France. (1927)</ref> He formulated an equation, commonly known as [[Ampere’s equation|Ampère's equation]] that describes the magnetic force between two electric currents and a [[Ampere's law|law]]&mdash;an incomplete version of one of [[Maxwell's laws]]&mdash;that relates an integral over a closed path in a magnetic field to the electric current through the surface bounded by the path.
Finally, in 1825 he presented his collected results to the Academy in one of the most celebrated memoirs in the history of natural philosophy.<ref>A. M.  Ampère, ''Mémoire sur une nouvelle expérience électro-dynamique, sur son application à la formule qui représente l'action mutuelle de deux éléments de conducteurs voltaïques, et sur de nouvelles conséquences déduites de cette formule: lu à l'Académie royale des sciences le 12 septembre 1825''.  [Memoir on a new electrodynamic experience, about its application to a formula that gives the mutual action between two Voltaic conductors and about the new consequences deduced from this formula: read at the Royal Academy of Sciences September 12, 1825] Annales de chimie et de physique, 1825, vol. '''29''' and '''30''', pp. 381-404 and p. 29-41.</ref> In 1827 he published a long memoir summarizing his  work on electricity and magnetism over the last seven years.<ref>A.-M. Ampère ''Théorie mathématique des phénomènes électro-dynamiques uniquement déduite de L'expérience'' [Mathematical theory of electrodynamic phenomena, uniquely deduced from experience.] Mémoires de l'académie royale des sciences de l'institut de France. (1827)</ref> He formulated an equation, commonly known as [[Ampere’s equation|Ampère's equation]] that describes the magnetic force between two electric currents and a law&mdash;now known as [[Ampere's law]], an incomplete version of one of [[Maxwell's laws]]&mdash;that relates an integral over a closed path in a magnetic field to the electric current through the surface bounded by the path.


Ampère’s theories were fundamental for nineteenth century developments in electricity and magnetism. [[James Clerk Maxwell]] writes of Ampère:  
Ampère’s theories were fundamental for nineteenth century developments in electricity and magnetism. [[James Clerk Maxwell]] writes of Ampère:  
Line 28: Line 30:
''We can scarcely believe that Ampère really discovered the law of action by means of the experiments which he describes. We are led to suspect, what, indeed, he tells us himself, that he discovered the law by some process which he has not shown us, and that when he had afterwards built up a perfect demonstration he removed all traces of the scaffolding by which he had raised it.''
''We can scarcely believe that Ampère really discovered the law of action by means of the experiments which he describes. We are led to suspect, what, indeed, he tells us himself, that he discovered the law by some process which he has not shown us, and that when he had afterwards built up a perfect demonstration he removed all traces of the scaffolding by which he had raised it.''
</blockquote>
</blockquote>
André-Marie Ampère died on June 10, 1836, in Marseilles, in his fifty-second year and was buried in Cimetiere de Montmartre, Paris.
In the last ten years of his life Ampère gradually lost interest in physics, for example, he did not follow the work of [[Michael Faraday]]. André-Marie Ampère died from pneumonia on June 10, 1836, when wintering in Marseilles, in his fifty-second year. In 1869 he was reburied in the cimetière  Montmartre in Paris.
==Reference==
Kenneth L. Caneva, ''Ampere, the Etherians, and the Oersted Connexion''
The British Journal for the History of Science, Vol. 13, No. 2. (Jul., 1980), pp. 121-138.
Stable URL: http://links.jstor.org/sici?sici=0007-0874%28198007%2913%3A2%3C121%3AATEATO%3E2.0.CO%3B2-U


==References==
==References==
<references />
<references />[[Category:Suggestion Bot Tag]]
Paul Jonathan Bruce, ''The History of Electromagnetic Theory'', Ph.D. Thesis, University of Aberdeen, 2005.
 
 
 
'''(To be continued)'''
<!--
 
André-Marie Ampère
 
Ampère was not known to be a methodical experimenter; he was subject to brilliant flashes of inspiration, which he would then pursue to their conclusion; during the week following Øersted’s discovery one such flash occurred. On 18 September 1820, exactly one week after the news of Øersted’s first discovery had arrived, Ampère attended a meeting at the Academy of Sciences and presented the Academy with the first of five papers of which he would write on the subject. He showed that two parallel wires carrying currents attract each other if the currents are in the same direction, and repel each other if the currents are in the opposite direction. The force between the two current carrying wires was inversely proportional to the distance separating them and proportional to the magnitude of current flowing through them; thus, Ampère had given birth to electrodynamics. During the following years he continued his researches, publishing in 1825 his collected results in one of the most celebrated memoirs in the history of natural philosophy – Memoir on the Mathematical Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience.
He formulated a law of electromagnetism, commonly known as Ampère’s law that mathematically describes the magnetic force between two electric currents. He pursued many experimental results, of which served to develop further mathematical theory that not only explained electromagnetic phenomena already reported but predicted new ones also.
Ampère was the first person to develop a technique for measuring electricity; he built an instrument utilising a free-moving needle to measure the flow of electricity, its later refinement being known as the galvanometer. Ampère used a highly sensitive galvanometer to make many of his experimental measurements. A galvanometer is simply a device used to detect and measure the flow of electricity; it is composed of a
compass with a wire wrapped around it. When either end of the wire is connected to whatever you want to test, such as a battery; the needle is deflected because a current has been created; the stronger the current the greater the deflection of the needle.
Ampère’s theories became fundamental for 19th century developments in electricity and magnetism. James Clerk Maxwell, whom we shall talk of later, in his memoirs, writes of Ampère: “We can scarcely believe that Ampère really discovered the law of action by means of the experiments which he describes. We are led to suspect, what, indeed, he tells us himself, that he discovered the law by some process which he has not shown us, and that when he had afterwards built up a perfect demonstration he removed all traces of the scaffolding by which he had raised it.”
André-Marie Ampère died on June 10, 1836, in Marseille, France, in his fifty-second year and was buried in Cimetiere de Montmartre, Paris.
1802 Professor für Physik in Bourg-en-Bresse
1804 Professor für Mathematik an der Ècole Polytechnique
1808 Generalinspekteur der Universität Paris
1824 Professor für Physik am Collège de France in Paris
 
 
MÉMOIRE
 
Présenté à l'Académie royale des Sciences, le 2 octobre 1820, où se trouve compris le résumé de ce
qui avait été lu à la même Académie les 18 et 25 septembre 1820, sur les effets des courans
électriques.
 
PAR M. AMPÈRE.
 
§1er. De l'Action mutuelle de deux courans électriques.
 
§ III. De l'Action mutuelle entre un conducteur électrique et un aimant (magnet).
 
C'est cette action découverte par M. OErsted, qui m'a conduit à reconnaître celle de deux courans
électriques l'un sur l'autre, celle du globe terrestre sur un courant, et la manière dont
l'électricité produisait tous les phénomènes que présentent les aimans, par une distribution
semblable à celle qui a lieu dans le conducteur d'un courant électrique, suivant des courbes fermées
perpendiculaires à l'axe de chaque aimant. Ces vues, dont la plus grande partie n'a été que plus
tard confirmée par l'expérience, furent communiquées à l'Académie royale des Sciences, dans sa
séance du 18 septembre 1820 ;
 
AMPERE, André-Marie. Mémoire présenté à l'Académie royale des Sciences, le 2 octobre 1820, où se trouve compris le résumé de ce qui avait été lu à la même Académie les 18 et 25 septembre 1820, sur les effets des courans électriques. Annales de chimie et de physique, 1820, vol. 15, p. 59-74, p.170-218
 
Chimie
 
Lettre de M. Ampère à M. le comte Berthollet sur la détermination des proportions dans lesquelles les corps se combinent d'après le nombre et la disposition respective des molécules dont les parties intégrantes sont composées, Annales de chimie, 1814, (vol. 90, n°1), p. 43-86.
 
 
Mathématiques
 
Considérations générales sur les intégrales des équations aux différences partielles, Journal de l'Ecole Polytechnique, 1815, (vol. 10, n°17), p. 549-611.
 
 
Electricité
 
Mémoire sur l'action mutuelle entre deux courants électriques, un courant électrique et un aimant ou le globe terrestre, et entre deux aimants, Annales de chimie et de physique, 1820, (vol. 15), p. 59-75, p. 170-218.
 
Mémoire sur la théorie mathématique des phénomènes électrodynamiques uniquement déduite de l'expérience, in Mémoires de l'Académie Royale des Sciences, année 1823, tome VI, 1827, p. 175-388.
“Memoir on the Mathematical Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience” (work by Ampere)
 
 
Ampère was present at the Académie des Sciences on Sept. 11, 1820, when François Arago performed - for the first time in France - Hans Christian Oersted’s experiment demonstrating the magnetic effects of current-carrying wires on magnetized needles. Inspired by Oersted’s discovery, Ampère immediately concluded that magnetism was electricity in motion, an intuitive leap which he sought to confirm by experiment.
 
During September and October 1820, Ampère per-formed a series of experiments designed to elucidate the exact nature of the relationship between electric current-flow and magnetism, as well as the relationships governing the behavior of electric currents in various types of conductors. His investigations, reported weekly before the Académie des Sciences, established the new science of electrodynamics.
 
 
Mémoire présenté à l’Académie royale des sciences
Annales de Chimie tome XV
André-Marie Ampère
1820
 
Ampère’s most detailed report on the events of September and October 1820 was published as a lengthy two-part memoir in the Annales de Chimie et de Physique. Written hurriedly and in disjointed segments, it is a rich source of information in spite of its chronological errors. . . .” (Hofmann, p. 238). Among the discoveries described in this memoir are Ampère’s demonstration of the tangential orientation of a magnetic needle by an electric current when terrestrial magnetism is neutralized; his proof that conducting planar spirals attract and repel each other and respond to bar magnets in an analogy to magnetic poles; and his demonstration of electrodynamic forces between linear conducting wires. The memoir’s plates illustrate the several instruments that Ampère devised to carry out his experiments (see below).
 
 
Ampère Table
1890
 
Ampère’s scientific genius, while capable of remarkable leaps of insight, was somewhat lacking in organization and discipline. It often happened that Ampère would publish a paper one week, only to find the following week that he had thought of several new ideas that he felt ought to be incorporated into the paper. Since he could not alter the original, he would add his revisions to the separately published reprints of the paper, and even modify the revised versions later if he felt it necessary; some of his papers exist in as many as five different versions.
 
A separate reprint of Ampère’s Mémoire was issued in 1821; however, it differs substantially from the journal publication, which must be considered the original version of this foundation document in electrodynamics.
 
DSB. Hofmann, Andre-Marie Ampère, ch. 7 (containing a detailed account of Ampère’s investigations). Norman 43 (1821 reprint). 37292
 
 
Kenneth L. Caneva, ''Ampere, the Etherians, and the Oersted Connexion''
The British Journal for the History of Science, Vol. 13, No. 2. (Jul., 1980), pp. 121-138.
Stable URL: http://links.jstor.org/sici?sici=0007-0874%28198007%2913%3A2%3C121%3AATEATO%3E2.0.CO%3B2-U
Arago, Fresnel, Ampere (wave theory, atomic theory and ether) against  Newtonians Biot and Laplace
1816 Ampere won over to the wave theory of light.
-->

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André-Marie Ampère (Lyons 20 January, 1775 – Marseilles 10 June, 1836) was a French physicist and mathematician. His most important contributions are Ampere's law, which describes the relation between electric current and magnetic field and Ampere's equation, which gives the force between two current carrying wires. The unit of electric current ampere is named after him.

Biography

André-Marie did not receive a formal education—he was tutored by his farther—and was a child prodigy. At the age of thirteen he submitted his first mathematical paper. This work attempted to solve the problem of constructing a line of the same length as an arc of a circle.[1] However, the work was refused and André-Marie realized that he had to become better skilled in mathematics. So, he read d'Alembert's article on the differential calculus in the Encyclopédie and undertook a study of works by Leonhard Euler and the Bernoullis (almost all these writings are in Latin). He started to read the 1788 edition of Lagrange's Mécanique analytique and later claimed that he was able to repeat all the calculations in it.

Four years after the French Revolution of 1789 Ampère's father was beheaded by the Jacobins. The effect on André-Marie of his father's death was devastating. François Arago relates in his 1839 eulogy of Ampère[2], that during these days André-Marie found consolation in the memory of three peaks in his young life: His first communion, the reading of Antoine-Léonard Thomas' eulogy of René Descartes, and the taking of the Bastille. After the execution of his father André-Marie gave up his studies of mathematics and only regained his taste for the sciences after he fell in love with his future wife, Cathérine-Antoinette (Julie) Carron. They married on August 2, 1799 and their son Jean-Jacques was born in 1800. In 1802 Ampère was appointed teacher of physics and chemistry in Bourg-en-Bresse at l'École Centrale du Département de l'Ain (now the Lycée Lalande). This was a difficult time for Ampère since Julie became ill and he had to leave her behind in Lyons. Nowadays Lyons and Bourg are seen as close (Bourg is about 60 km North-East of Lyons), but in the beginning of the nineteenth century travel was difficult. While Ampère was in Bourg he found time to perform research in mathematics. He wrote Considérations sur la théorie mathématique du jeu [Considerations on the Mathematical Theory of Games] in 1802. After his wife died in July 1803, Ampère decided to go to Paris.

He found a job as répétiteur d'analyse (tutor in analysis) at the École Polytechnique on 20 October 1804, where Augustin-Louis Cauchy was one of his students. Soon he embarked on a disastrous marriage (1806) with a girl called Jenny (Jeanne-Françoise Potot). Before the birth of their daughter Josephine-Albine on 6 July 1807, the couple had separated. They were legally divorced in 1808 and Ampère was given custody of their daughter. Notwithstanding these private problems, Ampère was productive in mathematics. Among other things he wrote about variational calculus and about the rest term of the Taylor series (1806).

In 1809 Ampère was promoted to professor of mathematical analysis at the École Polytechnique, a post he held until 1828. In 1824 he became also professor at the Collège de France where he was allowed to teach electrodynamics. In the first half of the 1820s Ampère and Cauchy shared the teaching of analysis at the École Polytechnique and both were criticized heavily at times, because it was judged that both mathematicans overloaded the future engineers by too much abstruse mathematics.

In November 1814 Ampère was elected to the Academy (not yet royal) of the Sciences of the Institut de France, when he defeated his former student Cauchy, who also applied for membership. For his denomination he had summarized the functions he had fulfilled thus far together with his mathematical contributions[3]. This was apparently a convincing résumé since it gained him the membership he applied for.

Also in 1814 he made independently the same discovery in chemistry[4] that Amedeo Avogadro made three years earlier, namely that the same volumes of different gases contain the same number of molecules. His work had the same fate as Avogadro's, their discovery went largely unnoticed by the chemists of the time.

In Parisian scientific circles of the 1810s there was some controversy about the theory of light. Augustin-Jean Fresnel had rejected Newton's corpuscular theory and had replaced it by a wave theory. Biot and Laplace still followed Newton, while François Arago and Ampère were on Fresnel's side. Doubtedlessly inspired by this discussion, Ampère published on the refraction of light in 1816.

From 1814 until 1820 Ampère did not perform the kind of research that would have made it into the annals of the history of science, but on September 11, 1820 when he heard François Arago speak about Oersted's work, he got fresh inspiration and started the work that made him famous. Arago related how Oersted had found that a steady electric current influences the orientation of a compass needle. After a week Ampère had determined experimentally that that two straight, parallel, and current-carrying, wires execute a force on each other. The magnitude of the force is inversely proportional to the distance between the wires and proportional to the strengths of the currents. This is what Ampère reported at a meeting of the Académie royale des Sciences on September 18, 1820 (see Ampere's equation). He was so excited about the phenomenon that he gave talks about it again on September 25 and October 2.[5]

During the following years he continued his researches, both experimentally and theoretically. He built an instrument for measuring electricity that later was developed into the galvanometer. Finally, in 1825 he presented his collected results to the Academy in one of the most celebrated memoirs in the history of natural philosophy.[6] In 1827 he published a long memoir summarizing his work on electricity and magnetism over the last seven years.[7] He formulated an equation, commonly known as Ampère's equation that describes the magnetic force between two electric currents and a law—now known as Ampere's law, an incomplete version of one of Maxwell's laws—that relates an integral over a closed path in a magnetic field to the electric current through the surface bounded by the path.

Ampère’s theories were fundamental for nineteenth century developments in electricity and magnetism. James Clerk Maxwell writes of Ampère:

We can scarcely believe that Ampère really discovered the law of action by means of the experiments which he describes. We are led to suspect, what, indeed, he tells us himself, that he discovered the law by some process which he has not shown us, and that when he had afterwards built up a perfect demonstration he removed all traces of the scaffolding by which he had raised it.

In the last ten years of his life Ampère gradually lost interest in physics, for example, he did not follow the work of Michael Faraday. André-Marie Ampère died from pneumonia on June 10, 1836, when wintering in Marseilles, in his fifty-second year. In 1869 he was reburied in the cimetière Montmartre in Paris.

References

  1. A.-M. Ampère, Sur la rectification d'un arc quelconque de cercle plus petit que la demi-circonférence [On the rectification of an arbitrary arc smaller than half the circumference of a circle], July 8, 1788
  2. F. Arago, Ampère, biographie, Lue par extraits en séance publique de l'académie des sciences, August 21 (1839)
  3. Notice des fonctions remplies et des principaux mémoires publiés ou lus à l'Institut et encore inédits, composés par A.M. Ampère. [Note on the functions fulfilled and the main memorandums published or presented at the Institut and not yet published, composed by A.M. Ampère]
  4. Lettre de M. Ampère à M. le comte Berthollet sur la détermination des proportions dans lesquelles les corps se combinent d'après le nombre et la disposition respective des molécules dont les parties intégrantes sont composées, [Letter of mr. Ampère to mr. the count Berthollet on the determination of the proportions in which bodies combine according to the number and the suitability of the molecules of which the integral parts are composed] Annales de chimie, vol. 90 pp. 43-86 (1814).
  5. A. M. Ampère, Mémoire présenté à l'Académie royale des Sciences, le 2 octobre 1820, où se trouve compris le résumé de ce qui avait été lu à la même Académie les 18 et 25 septembre 1820, sur les effets des courans électriques. [Memoir presented at the Royal Academy of Sciences, of October 2, 1820 where one finds a summary of the ones read before the same Academy on September 18 and 25, on the effects of electric currents]. Annales de chimie et de physique, vol. 15, pp. 59-74, and pp.170-218 (1820)
  6. A. M. Ampère, Mémoire sur une nouvelle expérience électro-dynamique, sur son application à la formule qui représente l'action mutuelle de deux éléments de conducteurs voltaïques, et sur de nouvelles conséquences déduites de cette formule: lu à l'Académie royale des sciences le 12 septembre 1825. [Memoir on a new electrodynamic experience, about its application to a formula that gives the mutual action between two Voltaic conductors and about the new consequences deduced from this formula: read at the Royal Academy of Sciences September 12, 1825] Annales de chimie et de physique, 1825, vol. 29 and 30, pp. 381-404 and p. 29-41.
  7. A.-M. Ampère Théorie mathématique des phénomènes électro-dynamiques uniquement déduite de L'expérience [Mathematical theory of electrodynamic phenomena, uniquely deduced from experience.] Mémoires de l'académie royale des sciences de l'institut de France. (1827)