**Colin MacLaurin**, mathematician, died on the 14th of June, 1746.

Colin MacLaurin was a child prodigy who became an eminent mathematician. By the time he was nineteen, he had become Professor of Mathematics at Marischal College, Aberdeen. He was a close friend and associate of Isaac Newton, who was so impressed by the young MacLaurin that he offered to pay his salary as Chair of Mathematics at the University of Edinburgh. MacLaurin’s meisterwerk, for which he is best remembered, was ‘Geometrica Organica’ (‘Organic Geometry, with the Description of the Universal Linear Curves’). His other chief works are on Calculus and Algebra, in addition to his ‘Account of Newton’s Discoveries’, published posthumously, in 1748. He is also known for the ‘Euler-Maclaurin formula’.

Colin MacLaurin was born at Kilmodan, on the Cowal Peninsula, in Argyll, in February, 1698. He never knew his father, who had died when Colin was six weeks old, and he was then orphaned, by the age of nine, when his mother died. After that, he was brought up by his uncle, who was the Minister at Kilfinnan, on Loch Fyne. At the age of eleven, Colin became a student at the University of Glasgow. You might be amazed at that, but it wasn’t so unbelievable for the time. Basically, the way things worked was that Scottish Universities competed for the best pupils, and MacLaurin was one of the elite.

MacLaurin’s abilities certainly began to show at Glasgow, but his first encounter with advanced mathematics came only after a year at the University, when he found a copy of Euclid’s ‘Elements’ in one of his friend’s rooms. That was the standard text for mathematical study at this time, but MacLaurin mastered the first six of what was a series of thirteen Greek textbooks, in quick fashion and through self-study. He also became interested in geometry at that time, which became a speciality and led to his ‘Organica’.

In 1712, MacLaurin was awarded the degree of M.A. (equivalent to a B.A. as the ancient Scottish universities retain the degree of M.A. as the first degree in Arts). Amazingly, MacLaurin had to defend his thesis in a public examination in order to get his degree. He chose to develop Newton’s theories as his topic and produced ‘On the power of gravity’. Even more amazing, consider this, was that he was only fourteen at the time and that such advanced ideas would only have been familiar to a small number of the elite mathematicians of the day.

MacLaurin stayed at Glasgow University for a further year to study divinity as it had been his intention to enter the Presbyterian Church. However, good man he was, he became “disgusted at the dissensions that had at that time crept into the church” and decided against that career. Then, in 1718, whilst still only nineteen, he was appointed Professor of Mathematics at Marischal College, in Aberdeen, as the result of a competitive examination. Believe it or not, MacLaurin’s record as the world’s youngest ever University Professor lasted until March, 2008. Later, on the 3rd of November, 1725, MacLaurin was appointed Chair of Mathematics at the University of Edinburgh, where he remained for the rest of his life. Despite Newton’s offer, there is no evidence to suggest that Edinburgh accepted any contribution to MacLaurin’s salary.

MacLaurin’s other chief work, the ‘Treatise of fluxions’, in which he dealt with the theorem of Calculus, maxima and minima, the attraction of ellipsoids, elliptic integrals, and the Euler-MacLaurin summation formula, was a source of influence across the Continent. He used the geometrical methods of the ancient Greeks, and Archimedes in particular, in order to provide a fundamental rigorous footing for Newton’s Calculus. Another important result given by MacLaurin, which has not been named after him or any other mathematician, is the important integral test for the convergence of an infinite series.

MacLaurin was elected a Fellow of the Royal Society, during his visit to London, in 1719, when he first made the acquaintance of Sir Isaac Newton. Earlier, whilst in France, he had been awarded a Grand Prize by the AcadÃ©mie des Sciences, the first of two such awards during his career. MacLaurin was also instrumental in the formation of the Royal Society of Edinburgh, which grew out of his expansion of the Medical Society of Edinburgh into one that dealt with broader scientific topics. The Royal Society formed after MacLaurin’s death, but was inspired by his enthusiasm and contributions.

With his broader interest in scientific subjects, MacLaurin also wrote about the annular eclipse of the sun and the structure of bees’ honeycombs. He also contributed to actuarial studies, being responsible for laying the sound actuarial foundations for the insurance society that has ever since helped the widows and children of Scottish Ministers and Professors.

Maclaurin was known for his strongly anti-Jacobite views and he played an active role in defending Edinburgh from the advancing ‘Rebel’ Army, being placed in charge of strengthening the walls. However, when the City fell, he was forced to flee to Newcastle and then made his way to York on the invitation of the Archbishop. A fall from a horse during the journey triggered an illness that was soon to claim his life. He returned to Edinburgh in November, 1745, after the Jacobite Army marched south, but with his strength sapped from the fall, the cold winter weather and his exertions on behalf of the City’s defences, he succumbed to illness and died on the 14th of June, 1746. Colin MacLaurin was buried in Greyfriars Kirkyard, where his grave can still be seen at the south-west corner.

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