Foster, Samuel

, an English mathematician, and professor of astronomy at Gresham college, was born in Northamptonshire or as Aubrey says, at Coventry, where he adds that he was some time usher of the school and was sent to Emanuel college, Cambridge, in 1616. He took the degree of B. A. in 1619, and of master in 1623. He applied early to the mathematics, and attained to great proficiency in that kind of knowledge, of which he gave the first specimen in 1624. He had an elder brother at the same college with himself, which precluded him from a fellowship; in consequence of which, he offered himself a candidate for the professorship of astronomy in Gresham college, Feb. 1636, and was elected the 2 d of March. He quitted it again, it does not appear for what reason, Nov. 25, the same year, and was succeeded therein by Mr. Mungo Murray, professor of philosophy at St. Andrew’s in Scotland. Murray marrying in 1641, his professorship was thereby vacated; and as Foster bad before made way for him, so he in his turn made way for Foster, who was re-elected May 22, the same year. The civil war breaking out soon after, he became one of that society of gentlemen, who had stated meetings for cultivating philosophy, and afterwards were established by charter, under the name of the royal society, in the reign of Charles II. In 1646, Dr. Wallis, another member of that society, received from Foster a mathematical theorem, which he afterwards published in his “Mechanics.” Neither was it only in this branch of science that he excelled, but he was likewise well versed in the ancient languages; as appear! from his revising and correcting the “Lemmata” of Archimedes, which had been translated from an Arabic manuscript into Latin, but not published, by Mr. John Greaves. He made also several curious observations upon eclipses, both of the sun and moon, as well at Gresham college, as in Northamptonshire, at Coventry, and in other places; and was particularly famous for inventing, as well as improving, astronomical and other mathematical instruments. After being long in a declining state of health, he died in July 1652, at his own apartment at Gresham college, and, according to Aubrey, was buried in the church of St. Peter le poor. His works are, 1. “The Description and use of -a small portable Quadrant, for the more easy finding of the hour of azimuth/' 1624, 4to, This treatise, which has been reprinted several times, is divided into | two parts, and was originally published at the end of Gunter’s” Description of the Cross Staffe in three hooks,“to which it was intended as an appendix. 2.” The Art of Dialling,“1638, 4to. Reprinted in 1675, with several additions and variations from the author’s own manuscript, as also a supplement by the editor William Leybourne. Our author himself published no more, yet left many other treatises, which, though not finished in the manner he intended, were published by his friends after his death as, 3.” Posthuinu Fosteri containing the description of a Ruler, upon which are inscribed divers scales, &c.“1652, 4to. This was published by Edmund Wingate, esq. 4.” Four Treatises of Dialling,“1654, 4to. 5.” The Sector altered, and other scales added, with the description and use thereof, invented and written by Mr. Foster, and now published by William Leybourne, 1661,“4to. This was an improvement of Gunter’s Sector, and therefore published among his works. 6.” Miscellanies, or Mathematical Lucubrations of Mr. Samuel Foster, published, and many of them translated into English, by the care and industry of John Twysden, C. L. M. D. whereunto he hath annexed some things of his own." The treatises in this collection are of different kinds, some of them written in Latin, some in English.

There have been two other persons of this name, who have published mathematical pieces. The first was William Foster, who was a disciple of Mr. Oughtred, and afterwards a teacher of mathematics in London. He distinguished himself by a book, which he dedicated to sir Kenelm Digby, with this title, “The Circles of Proportion, and the Horizontal Instrument, &c.1633, 4to, The other was Mark Foster, who published “A Treatise of Trigonometry,” but lived later in point of time than either of the other two. 1


Biog. Brit. Ward’s Gresham Professors. Letters by eminent persons, 3 vols. 8vo, 1813.