Editing Matthew Stewart (mathematician) (section)

==Life==

He was born in the manse at [[Rothesay, Argyll and Bute|Rothesay]], on the [[Isle of Bute]], on 15 January 1717,<ref>{{cite ODNB|first=E. I.|last=Carlyle|title=Stewart, Matthew (1717–1785)|edition=Online|year=2004|url=http://www.oxforddnb.com/view/article/26498|accessdate=2015-10-05|doi=10.1093/ref:odnb/26498}} </ref> the son of Rev Dugald Stewart, the local minister, and his wife, Janet Bannantyne.<ref name="auto">{{cite book|title=Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002|date=July 2006|publisher=The Royal Society of Edinburgh|isbn=0-902-198-84-X|url=https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|access-date=9 September 2018|archive-url=https://web.archive.org/web/20160304074135/https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf|archive-date=4 March 2016|url-status=dead}}</ref>

He was educated at Rothesay Grammar School, then entered the [[University of Glasgow]] in 1734, where he studied under the philosopher [[Francis Hutcheson (philosopher)|Francis Hutcheson]] and the mathematician [[Robert Simson]], the latter from whom he studied ancient [[geometry]]. A close friendship developed between Simson and Stewart, in part because of their mutual admiration of [[Pappus of Alexandria]], which resulted in many curious communications with respect to the De Locis Planis of [[Apollonius of Perga]] and the Porisms of [[Euclid]] over the years.<ref>John Playfair, Biographical Account of Matthew Stewart, D.D., ''Transactions of the Royal Society of Edinburgh'', Vol. 1 (1788). The correspondence appears in J.S. Mackay, Mathematical correspondence - Robert Simson, Matthew Stewart, James Stirling,'' Proceedings of the Edinburgh Mathematical Society'', Vol. 21 (1903), pp. 2-39.</ref> This correspondence suggests that Stewart spent several weeks in Glasgow starting May 1743 assisting [[Robert Simson]] in the production of his ''Apollonii Pergaei locorum planorum libri II'', which was published in 1749.

However, his father persuaded him to enter the ministry (this was a normal father-son expectation in the ministry). He studied Divinity at [[Edinburgh University]] in the year 1742/43 also attending maths lectures under [[Colin Maclaurin]]. He was licensed by the Presbytery of the Church of Scotland of [[Dunoon]] in May 1744, and became a minister at [[Rosneath]] in [[Dumbartonshire]] one year later.

In 1746, following the death of Colin Maclaurin, the chair as Professor of Mathematics became vacant at Edinburgh University and just over one year later Stewart left the ministry to become Professor of Mathematics. Publication of his best known work, ''Some General Theorems of Considerable use in the Higher Parts of Mathematics'' may have helped him secure the post.<ref>Downloadable version available in Google Books.</ref> This book extended some ideas of [[Robert Simson]] and is best known for proposition II, or what is now known as [[Stewart's theorem]], which relates measurements on a triangle to an additional line through a vertex.<ref>{{Cite web|url=https://www.youtube.com/watch?v=cRebl8I0lKk |archive-url=https://ghostarchive.org/varchive/youtube/20211212/cRebl8I0lKk| archive-date=2021-12-12 |url-status=live|title=See video presentation on YouTube|website=[[YouTube]] |accessdate=7 October 2020}}{{cbignore}}</ref> Stewart also provided a solution to Kepler's problem using geometrical methods in 1756,<ref>Second volume of the Essays of the Philosophical Society of Edinburgh</ref> and a book describing planetary motion and the perturbation of one planet on another in 1761, along with a supplement on the distance between the Sun and Earth in 1763, ''Tracts Physical and Mathematical'' and ''The Distance of the Sun from the Earth determined by the Theory of Gravity'' respectively. The latter work overestimated the distance by more than 25%, for which his geometrical method received some criticism for being oversimplified.

In 1772 his health began to deteriorate and his duties as professor at Edinburgh were initially shared, then taken over by, his son [[Dugald Stewart]], who later became a prominent Scottish philosopher. Matthew ceased teaching in 1775 but continued to play a role in Edinburgh society, most notably being a joint founder of the [[Royal Society of Edinburgh]] in 1783.<ref name="auto"/>