Editing Augustin-Louis Cauchy (section)

===Last years===
Cauchy returned to Paris and his position at the Academy of Sciences late in 1838.{{sfn|Bruno|Baker|2003|p=67}} He could not regain his teaching positions, because he still refused to swear an oath of allegiance.

[[File:Augustin-Louis Cauchy.jpg|thumb|left|Cauchy in later life]]
In August 1839 a vacancy appeared in the [[Bureau des Longitudes]]. This Bureau bore some resemblance to the academy; for instance, it had the right to co-opt its members. Further, it was believed that members of the Bureau could "forget about" the oath of allegiance, although formally, unlike the Academicians, they were obliged to take it. The Bureau des Longitudes was an organization founded in 1795 to solve the problem of determining position at sea — mainly the [[longitude|longitudinal]] coordinate, since [[latitude]] is easily determined from the position of the sun. Since it was thought that position at sea was best determined by astronomical observations, the Bureau had developed into an organization resembling an academy of astronomical sciences.

In November 1839 Cauchy was elected to the Bureau, and discovered that the matter of the oath was not so easily dispensed with. Without his oath, the king refused to approve his election. For four years Cauchy was in the position of being elected but not approved; accordingly, he was not a formal member of the Bureau, did not receive payment, could not participate in meetings, and could not submit papers. Still Cauchy refused to take any oaths; however, he did feel loyal enough to direct his research to [[celestial mechanics]]. In 1840, he presented a dozen papers on this topic to the academy. He described and illustrated the [[signed-digit representation]] of numbers, an innovation presented in England in 1727 by [[John Colson]]. The confounded membership of the Bureau lasted until the end of 1843, when Cauchy was replaced by Poinsot.

Throughout the nineteenth century the French educational system struggled over the separation of church and state. After losing control of the public education system, the Catholic Church sought to establish its own branch of education and found in Cauchy a staunch and illustrious ally. He lent his prestige and knowledge to the [[École Normale Écclésiastique]], a school in Paris run by Jesuits, for training teachers for their colleges. He took part in the founding of the [[Institut Catholique de Paris|Institut Catholique]]. The purpose of this institute was to counter the effects of the absence of Catholic university education in France. These activities did not make Cauchy popular with his colleagues, who, on the whole, supported [[the Enlightenment]] ideals of the French Revolution. When a chair of mathematics became vacant at the Collège de France in 1843, Cauchy applied for it, but received just three of 45 votes.

In 1848 King Louis-Philippe fled to England. The oath of allegiance was abolished, and the road to an academic appointment was clear for Cauchy. On March 1, 1849, he was reinstated at the Faculté de Sciences, as a professor of mathematical astronomy. After political turmoil all through 1848, France chose to become a Republic, under the Presidency of [[Napoleon III of France]]. Early 1852 the President made himself Emperor of France, and took the name [[Napoleon III]].

The idea came up in bureaucratic circles that it would be useful to again require a loyalty oath from all state functionaries, including university professors. This time a cabinet minister was able to convince the Emperor to exempt Cauchy from the oath. In 1853, Cauchy was elected an International Member of the [[American Philosophical Society]].<ref>{{Cite web |title=APS Member History |url=https://search.amphilsoc.org/memhist/search?creator=Cauchy&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced |access-date=2024-04-24 |website=search.amphilsoc.org}}</ref> Cauchy remained a professor at the university until his death at the age of 67. He received the [[Last Rites]] and died of a bronchial condition at 4&nbsp;a.m. on 23 May 1857.{{sfn|Bruno|Baker|2003|p=67}}

His name is one of the [[List of the 72 names on the Eiffel Tower|72 names inscribed on the Eiffel Tower]].