**André-Marie Ampère** made important contributions to the theory of Electricity and magnetism. His theory became fundamental for 19th century developments.

- Despite not attending school, André-Marie was to be given an excellent education.
- Before being able to read, the young Ampère's greatest pleasure was to listen to passages from Buffon's natural history.
- Ampère read articles from L'Encyclopédie many of which, Arago remarked many years later, he could recite in full in later life.
- Arago also claims that Ampère read the Encyclopédie starting at volume 1 and reading the articles in alphabetical order.
- Whether Ampère's later desire for classification in all subjects arose from this education, or whether he enjoyed Buffon and the Encyclopédie because of a natural liking for classifying, is hard to say.
- It has been claimed that Ampère had mastered all known mathematics by the age of twelve years but this seems somewhat of an exaggeration since, by Ampère's own account, he did not start to read elementary mathematics books until he was 13 years old.
- However Ampère was always one to feel very confident in his own abilities and he certainly began to develop his own mathematical ideas very quickly and he began to write a treatise on conic sections.
- Ampère had no contacts with anyone with any depth of mathematical knowledge so it is not surprising that he felt that his ideas were original.
- While still only 13 years old Ampère submitted his first paper to the Académie de Lyon.
- His method involves the use of infinitesimals but since Ampère had not studied the calculus the paper was not found worthy of publication.
- Shortly after writing the article Ampère began to read d'Alembert's article on the differential calculus in the Encyclopédie and realised that he must learn more mathematics.
- After taking a few lessons in the differential and integral calculus from a monk in Lyon, Ampère began to study works by Euler and Bernoulli.
- Ampère continued tutoring mathematics until 1802 when he was appointed professor of physics and chemistry at Bourg École Centrale.
- This was a difficult time for Ampère since Julie became ill before he made the move to Bourg leaving her at Poleymieux.
- While Ampère was in Bourg he spent much time teaching physics and chemistry but his research was in mathematics.
- Laplace noticed an error, explaining the error to Ampère in a letter, which Ampère was able to correct and the treatise was reprinted.
- The treatise was modified a number of times and Ampère was reluctant to call it completed for fear that further changes might be required.
- After a year in Bourg, Ampère moved closer to Poleymieux being appointed to a mathematics position at the Lycée in Lyon on Delambre's recommendation.
- Like a number of other mathematicians, Ampère seemed able to concentrate on his theorems despite the personal tragedy around him and, sadly, this would be required of him throughout his unhappy life.
- Although Ampère gradually adjusted to the priority disputes and infighting of the Parisian scientific community, he always longed for a return to the intellectual life he experienced in Lyon.
- By this time Ampère had a fair reputation as both a teacher of mathematics and as a research mathematician and on the strength of this reputation he was appointed répétiteur (basically a tutor) in analysis at the École Polytechnique in 1804.
- Ampère and Cauchy shared the teaching of analysis and mechanics and there was a great contrast between the two with Cauchy's rigorous analysis teaching leading to great mathematical progress but found extremely difficult by students who greatly preferred Ampère's more conventional approach to analysis and mechanics.
- Ampère was appointed to a chair at Université de France in 1826 which he held until his death.
- In Paris Ampère worked on a wide variety of topics.
- Ampère was also making significant contributions to chemistry.
- After concentrating on mathematics as he sought admission to the Institut, Ampère returned to chemistry after his election in 1814 and produced a classification of elements in 1816.
- Ampère also worked on the theory of light, publishing on refraction of light in 1815.
- Fresnel became a good friend of Ampère's and lodged at Ampère's home from 1822 until his death in 1827.
- In the early 1820s, Ampère attempted to give a combined theory of electricity and magnetism after hearing about experimental results by the Danish physicist Hans Christian Orsted.
- Ampère formulated a circuit force law and treated magnetism by postulating small closed circuits inside the magnetised substance.
- It is worth commenting on how quickly Ampère produced this theory, the inspiration striking him immediately he heard of Orsted's experimental results.
- Ampère demonstrated various magnetic / electrical effects to the Academy over the next weeks and he had discovered electrodynamical forces between linear wires before the end of September.
- Ampère wrote up the work he had described to the Academy with remarkable speed and it was published in the Annales de Chimie et de Physique.
- But more than his creativity, it was Savary's discipline and ability to concentrate at length on specific problems that proved especially valuable to Ampère.
- Ampère might never have found time to complete the detailed calculations required to apply his force law to magnetic phenomena.
- However Ampère was not the only one to react quickly to Arago's report of Orsted's experiment.
- Ampère's most important publication on electricity and magnetism was also published in 1826.
- Ampère's theory became fundamental for 19th century developments in electricity and magnetism.
- Faraday discovered electromagnetic induction in 1821 and, after initially believing that he had himself discovered the effect in 1822, Ampère agreed that full credit for the discovery should go to Faraday.
- Weber also developed Ampère's ideas as did Thomson and Maxwell.
- In 1826 Ampère began to teach at the Collège de France.
- Ampère therefore taught electrodynamics at the Collège de France and this course was taken by Liouville in 1826-27.
- This was the second time Ampère had taught Liouville since Liouville had taken Ampère's courses at the École Polytechnique in the previous session.
- Liouville made an important contribution to Ampère's electrodynamics course by editing a set of notes taken from Ampère's lectures.
- Ampère's home simply was not expansive to house both of them for any extended period of time.
- This proved a difficult situation, led to police intervention and much unhappiness for Ampère.

Born 20 January 1775, Lyon, France. Died 10 June 1836, Marseilles, France.

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Puzzles And Problems

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive