In the mean time, he was continually obliging the public with some observa• tion or performance of his own, several of which were published in the fifth and sixth volumes of the Medical Essays at Edinburgh. Many of- them were like wise published in the Philos. Trans. as the following : 1. On the construction and measure of curves, vol. 30.-2. A new method of describing all kinds of curves, vol. 30.-3. On equations with impossible roots, vol. 34.-4. On the roots of equa tions, &c. vol. 34.-5. On the description of curve lines, vol. 39.-6. Continuation of the same, vol. 39.-7. Observations on a solar eclipse, vol. 40.-8 A rule for finding the meridional parts of a sphe roid, with the same exactness as in a sphere, vol. 41.-9. An account of the treatise of fluxions, vol. 42.-10. On the basis of the cells, where the bees deposit their honey, vol. 42.
In the midst of these studies, he was always ready to lend his assistance in contriving and promoting any scheme which might contribute to the public service. When the Earl of Morton went, in 1739, to visit his estates in Orkney and Shetland, he requested Mr. Maclaurin to assist him in settling the geography of those countries, which is very erroneous in all our maps ; to examine their natural history, to survey the coasts, and to take the measure of a degree of the meridian. Maclanrin's family affairs would not per mit him to comply with this request ; he drew up however a memorial of what he thought necessary to be observed, and furnished proper instruments for the work, recommending Mr. Short, the noted optician, as a fit operator for the management of them.
Mr. Maclaurin had still another scheme for the improvement of geography and navigation, of a more extensive nature ; which was, the opening a passage from Greenland to the South Sea by the north pole. That such a passage might be found, he was so fully persuaded, that lie used to say, if his situation could admit of such adventures, he would undertake the voyage, even at his own charge. But when schemes for finding it were laid be fore the parliament in 1741, and he was consulted by several persons of high rank concerning them, and before he could finish the memorial he proposed to send, the premium was limited to the discovery of a north-west passage ; and he used to regret that the word west was inserted, because he thought that passage, if at all to be found, must lie not far from the pole.
In 1745, having been very active in for, tifying the city of Edinburgh against the rebel army, he was obliged to fly from thence into England,. where he was in
vited by Dr. Herring, Archbishop of York, to reside with him during his stay in this country. In this expedition, how ever, being exposed to cold and hard ships, and naturally of a weak and ten, der constitution, which had been much more enfeebled by close application to Study, he laid the foundation of an ill ness which put an end to his life, in June 1746, at forty-eight years of age, leaving his widow with two sons and three daughters.
Mr. Maclaurin was a very good, as well as a very great man, and worthy of love as well as admiration. His peculiar merit as a philosopher was, that all his studies were accommodated to general utility ; and we find, in many places of his works, an application, even of the most abstruse theories, to the perfecting of mechanical arts. For the same pur pose be had resolved to compose a course of practical mathematics, and to rescue several useful branches of the science from the ill treatment they often met with in less skilful hands. These intentions however were prevented by his death ; unless we may reckon, as a part of his in tended work, the translation of Dr. David Gregory's Practical Geometry, which he revised, and published with additions, in 1745.
In his life-time, however, he had fre quent opportunities of serving his friends and his country by his great skill. What ever difficulty occurred concerning the constructing or perfecting of machines, the working of mines, the improving of manufactures, the conveying of water, or the execution of any public work, he was always ready to resolve it. He was em ployed to terminate some disputes of con sequence that had arisen at Glasgow, con cerning the gauging of vessels ; and for that purpose presented to the commis sioners of the excise two elaborate me morials, with their demonstrations, con taining rules by which the officers now act. He made also calculations relating to the provision, now established by law, for the children and widows of the Scotch clergy, and of the professors in the uni versities, entitling them to certain annui ties and sums, upon the voluntary an nual payment of a certain sum by the in cumbent. In contriving and adjusting this wise and useful scheme, he be stowed a great deal of labour, and con tributed not a little towards bringing it to perfection.