SINCLAIR, George, a well-known mathematical writer, was professor of philosophy in the university of Glasgow in the latter part of the seventeenth century. No particulars of his early life have been ascertained. He was admitted a professor of Glasgow university, April 18, 1654,[1] and was ejected in 1662, for declining to comply with the episcopal form of church government, then thrust upon the people of Scotland. He had, in the previous year, published at Glasgow, his first known work, "Tyrocinia mathematica, in novem tractatus, viz., mathematicum, spile ricum, geographicum, et echometricum, divisa," Id mo. After his ejection, he betook himself to the business of a mineral surveyor and practical engineer, and was employed in that profession by several proprietors of mines in the southern parts of Scotland, and particularly by Sir James Hope, who, having sat in Barebones' parliament, was probably nowise averse to his presbyterian principles. In 1669, he published at Rotterdam, "Ars Nova et Magna Gravitatis et Levitatis," 4to. He was employed by the magistrates of Edinburgh, about 1670, to superintend the introduction of water from Cormiston into the city; a convenience with which the capital of Scotland had not previously been furnished. Considerable attention seems to have been paid by him to such branches of hydrostatics as were of a practical nature; and it has been said that he was the first person who suggested the proper method of draining the water from the numerous coal mines in the southwest of Scotland. In 1672, he published at Edinburgh a quarto entitled, "Hydroslaticks; or, the Force, Weight, and Pressure of Fluid Bodies, made evident by physical and sensible Experiments, together with some Miscellany Observations, the last whereof is a short history of Coal." And, in 1680, he published at the same place, in Svo, what appears to have been a modification of the same work, "Hydrostatical Experiments, with Miscellany Observations, and a relation of an Evil Spirit; also a Discourse concerning Coal." Sinclair's writings, in the opinion of a very able judge, are not destitute of ingenuity and research, though they may contain some erroneous and eccentric views. The work last named contained a rather strange accompaniment to a scientific treatise, an account of the witches of Glenluce, which, if there had been no other evidence of the fact, shows the author to have not been elevated by his acquaintance with the exact sciences above the vulgar delusions of his age. It must be recollected, however, that other learned men of that age were guilty of like follies. The self-complacency of Sinclair, and his presbyterian principles provoked the celebrated James Gregory, then a professor at St Andrews, to attack his Hydrostatics in a pamphlet published with the quaint title of the "Art of Weighing Vanity," and under the thin disguise of Patrick Mather, archbeadle of the university of St Andrews. It is curious to observe that with all his eagerness to heap ridicule on his antagonist, Gregory never once touches on what would now appear the most vulnerable point, the episode about the witches. After a long interval, Sinclair wrote an answer to Gregory, entitled, "Cacus pulled out of his den by the heels, or the pamphlet entitled, the New and Great Art of Weighing Vanity examined, and found to be a New and Great Act of Vanity." But this production was never published: it remains in manuscript in the university library at Glasgow, to
which the author appears, from an inscription, to have presented it in 1692. Sinclair was among the first in Britain who attempted to measure the heights of mountains by the barometer. It is said that Hartfell, near Moffat, was the first hill in Scotland of Avhich the height was thus ascertained. In the years 1668 and 1670, he observed the altitudes of Arthur's Seat, Leadhills, and Tinto, above the adjacent plains. He followed the original mode of carrying
- ↑ Records of the University.
