Charles Platts

“ In 1836 McCullagh was elected professor of mathematics and in 1843 professor of natural philosophy in the university of Dublin. He threw himself into his duties as a teacher with an ardour which communicated itself to his pupils, and gave a powerful stimulus to mathematical and physical studies in the university. He introduced the studies of electricity and galvanism, heat and terrestrial magnetism into the fellowship course.
As secretary of council to the Royal Irish Academy from 1840 to 1842, and as secretary to the Academy from 1842 to 1846, he rendered that institution valuable service. ”

“ Leslie expressly dissents from his conclusions, rejecting Wells's idea of heat radiations from the earth's surface in favour of his own notion of a ‘continual darting of cold pulsations by day and night from an azure sky.’ Leslie clung with curious tenacity to his theory that cold had an objective existence distinct from heat. In 1809 he began to write for the ‘Edinburgh Review,’ to which he contributed articles on ‘The Physical and Chemical Memoirs of the Society of Arcueil’ (vol. xv.) ”

“ LEYBOURN, WILLIAM (1626–1700?) , mathematician, born in 1626, was a teacher of mathematics and professional land surveyor in London. He is said to have begun life as a printer; but as early as 1648 he appears as joint author with Vincent Wing [q. v.] of the first book on astronomy written in English; its title was ‘Urania Practica,’ and it was adapted to the comprehension of beginners. Its authors are styled ‘practitioners in the mathematicks.’ It reached a second edition in 1649, and was criticised by Jeremie Shakerley in ‘The Anatomy of Urania Practica,’ 1649 ”

“ His engagement at Etruria ended, Leslie spent a few months in Holland, and then, returning to Largo, devoted ten years to study and experimental research. He invented several instruments for use in the sciences of heat and meteorology, of which the differential thermometer may be taken as the type. His life at Largo was diversified by visits to London and by continental travel. ”

“ In 1584 he returned to Frankfort, took pupils in mathematics and philosophy, and applied himself to the study of physic. In 1587 an epidemic drove him to Rostock, where he became the friend of Caselius and Brucæus, and received the degree of master in philosophy. He had hardly returned to Frankfort once more in 1590 when he was persuaded to attach himself to the new university of Helmstadt, established by Duke Julius of Brunswick. Caselius had already been appointed to the chair of philosophy there. ”

“ The algebra is an elementary treatise, dealing principally with equations, and with the application of algebra to geometry; it is a model of clear and terse exposition, and was in vogue as a Cambridge text-book for more than half a century (Wordsworth, University Studies) . 4. 'An Account of Sir Isaac Newton's Philosophy,' published by subscription by Patrick Murdoch for the benefit of Maclaurin's children, and prefaced by a memoir of the author. ”

“ His work obtained speedy recognition from the Royal Society of London, which awarded him the Rumford medal in 1805. In the same year Professor Playfair exchanged the chair of mathematics at Edinburgh for that of natural philosophy, and Leslie was elected to the vacant chair in March 1805, in spite of the united opposition of the ministers of Edinburgh, who, on the ground that he had quoted with approval in his book some of Hume's remarks on causation, professed to see in him a champion of freethought. ”

“ LUDLAM, WILLIAM (1717–1788) , mathematician, born at Leicester in 1717, was elder son of Richard Ludlam (1680–1728) , who graduated M.B. at St. John's College, Cambridge, in 1702, and practised medicine at Leicester. Thomas Ludlam [q. v.] was his youngest brother. His mother was Anne, daughter of William Drury of Nottingham. His uncle, Sir George Ludlam, was chamberlain of the city of London, and died in 1726. ”

“ MACKAY, ANDREW (1760–1809) , mathematician, was born in 1760 and lived in Aberdeen. He was in October 1781 appointed keeper (without salary) of the observatory on the Castle hill (see Aberdeen Journal, 15 Oct. 1781) , and here he made his calculations on the latitude and longitude of his native town (see infra) . He was created LL.D. of Aberdeen in 1786, and was also fellow of the Royal Society of Edinburgh, honorary member of the Literary and Philosophical Society of Newcastle-on-Tyne, mathematical examiner to the corporation of Trinity House (1805-9) and to the East India Company. ”

“ He had in his early years a strong desire to study astronomy; the opportunity of gratifying it came when, through the joint influence of the rector of the parish and Thomas Cholmondeley, afterwards first baron Delamere, he received an appointment in the excise. The telescopes he used in his observations were of his own construction. In 1812 he began to apply astronomical results to biblical chronology, especially to the questions arising out of the scriptural genealogies of Christ, and published in 1817 'The Genealogy of Christ elucidated by Sacred History ... ”

“ To the first volume of the seventh edition of the ‘Encyclopædia Britannica’ he contributed a ‘Discourse on the Progress of Mathematical and Physical Science during the 18th Century,’ a work for which the extent of his knowledge and the ripeness of his judgment peculiarly fitted him. ”

“ He edited (London, 1680, 8vo) the second edition of ‘The City and Country Purchaser and Builder,’ by Stephen Primatt. The fourth edition of Scamozzi's ‘Mirror of Architecture’ (London, 1700, 4to) has William Leybourn's name as editor. The year of his death is uncertain.
Leybourn's works all grew out of his teaching, and were deservedly popular. They are clear and attractive in style, and are the work of a man of considerable ingenuity and uncommon industry. ”

“ 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. ”

“ Trans.' in 1735 (p. 439) ; it contains the general theorem, from which Pascal's follows as a corollary, that if a polygon be deformed so that all its sides passing respectively through fixed points, all its vertices except the last describe given curves of orders m, n, p, . . ., the last will describe a curve of order 2 m n p . . ., which will be lowered by m n p . . . when the fixed points lie on a straight line. These geometrical researches of Maclaurin were afterwards the starting point of further developments by Poncelet and others. 2. 'A Treatise of Fluxions,' 2 vols. Edinburgh, 1742. ”

“ LOWRY, JOHN (1769–1850) , mathematician, a native of Cumberland, was for some time an excise officer at Solihull, near Birmingham, but in 1804 he obtained an appointment as master of arithmetic in the new military college at Great Marlow. ”

“ 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 ”

“ 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. ”

“ Shortly before his death he unsuccessfully contested Dublin University in the nationalist interest. He died by his own hand in October 1847, in a fit of temporary insanity. Dyspepsia and overwork appear to have intensified a mental disorder of which he had shown slight symptoms long before. ”

“ Numbers, commonly called Gunter's Line, made easie,’ 12mo, a treatise on the sliding-rule; a second part was published in 1677 (other editions, 1678 and 1684) . In 1662 and 1673 he produced the fourth and fifth editions of the ‘Works’ of Edmund Gunter [q. v.] , adding some rules of his own for the mensuration of plane and solid figures. ”

“ In his later years he took pupils in London at his house in George Street, Trinity Square; he taught mathematics and natural philosophy, navigation, architecture, and engineering. He died on 3 Aug. 1809, leaving a widow and children, and was buried in Allhallows Barking. ”

“ Next year Liddel obtained the lower mathematical chair vacated by Parcovius, and in 1594 he succeeded Erhardus Hoffmann in the higher mathematical chair. In 1596 he became M.D. of the university, and began publicly to teach physic and to act as præses at the recitation of medical dissertations. ”

“ His report is given in the ‘Gentleman's Magazine,’ 1765, pt. i. p. 412. He enjoyed considerable reputation at the time for his skill in practical mechanics and astronomy, as well as for his mathematical lectures. ”