Page:Dictionary of National Biography volume 35.djvu/202

 .  'Celtic Gleanings,' Edinburgh, 857; four lectures delivered before Edinburgh University students.  'The Book of Common Order,' translated into Gaelic, 1878.  Two sermons—'The Way to God' (1868) and 'The Wrath and the Refuge,' sermon as moderator of the free church assembly (1877).

He also edited the third edition of Stewart's 'Rudiments of Gaelic Grammar,' Edinburgh, 1876.

 MACLAURIN, COLIN (1698–1746), mathematician and natural philosopher, was born at Kilmodan, N.B., in February 1698. His grandfather, Daniel Maclaurin, removed from an ancestral estate on the island of Tirrie, off Argyleshire, to Inverara, and helped to restore that town after the ruin of the civil wars; he was the author of some memoirs of his own times. His son John was minister of Glendaruel and afterwards of Kilmodan, and the author of an Irish version of the Psalms; by his marriage with a lady named Cameron he had three sons: John, who is noticed separately, Daniel, who died young, and Colin. He died six weeks after Colin's birth, and his wife died in 1707, having in the interval removed to Dumbarton for the sake of her children's education. Colin Maclaurin was thus, in his tenth year, left entirely to the care of his uncle, Daniel Maclaurin, minister of Kilfinan, Argyllshire, who sent him in 1709 to the university of Glasgow. His mathematical genius soon showed itself; many of the propositions which afterwards appeared in his 'Geometria Organica' were invented by him during his five years' course at the university. In his fifteenth year he took the degree of M.A, and wrote for this occasion a thesis ' On the Power of Gravity.' After a year spent in the study of divinity he quitted the university and went to live with his uncle.

In September 1717 he obtained the professorship of mathematics in the Marischal College of Aberdeen. The examiners reported that both 'M'Laurine' and his rival Walter Bowman 'were capable to teach Mathematicks anywhere.' In Euclid Mr. Bowman was much readier and distincter, but 'in the last tryall, M'Laurine plainly appeared better acquainted with the speculative and higher pairts of the Mathematicks' (Fasti Acad. Mariscallana, ed. P. J. Anderson, i. 147). In the vacations of 1719 and 1721 he visited London; on his first visit he made the acquaintance of Sir Isaac Newton and was admitted a member of the Royal Society; on his second visit he formed an intimate friendship with its president, [q. v.] In 1722 Lord Polwarth, plenipotentiary of Great Britain at the congress of Cambray, engaged Maclaurin as travelling tutor to his eldest son. They spent some time together in Lorraine, where Maclaurin wrote a memoir on the percussion of bodies, which gained him in 1724 the prize of the Royal Academy of Sciences, and the substance of which was afterwards embodied in his treatise on fluxions. At Montpellier his pupil died, and Maclaurin returned to his professorial duties at Aberdeen. On 27 April 1725 he appeared before the council and expressed his regret for the long absence without leave with which they reproached him; he was 'reponed' for the time, but in the following anuary his office was declared vacant, and in February he sent in his demission (ib. p. 148). He had in fact during the previous November removed to the university of Edinburgh as deputy professor to (1753–1821) [q. v.], whom age and infirmity had rendered incapable of teaching. For this appointment he was largely indebted to the influence of Newton, who wrote strongly recommending him to the patrons of the university, and promising to contribute 20l. a year towards the stipend if Maclaurin were appointed.

Maclaurin's classes at Edinburgh were numerously attended. During the session 1 Nov. to 1 June he spent four or five hours every day in teaching. He became a man of wide influence and many friends; and he used to the fullest extent the opportunities of usefulness opened to him. His skill in experimental physics, in astronomical observations, and in practical mechanics was constantly placed at the service both of public bodies and private individuals. He made the actuarial calculations for an insurance fund established by law for the widows and children of the Scottish clergy and professors in the universities. He extended the medical society of Edinburgh so as to include physics and antiquities, and became secretary of the new society, with Dr. Plummer as his colleague, the Earl of Morton being the first president. He proposed an astronomical observatory for Scotland, improved the maps of Orkney and Shetland, and was a firm believer in the existence of a north-polar passage.

In 1745 it was Maclaurin who organised the defences of Edinburgh against the rebel troops; he was employed night and day in planning the hastily raised fortifications and