FOSTER, Samuel, an English mathematician and professor of astronomy at Gresham College, was one of that learned association which met for cultivating the new philosophy, and which Charles II. established as the Royal Society. Mr Foster, however, died in 1652, before this incorporation took place; but he wrote a number of mathematical and astronomical treatises, particularly, 1. The Description and Use of a small portable Quadrant, for the more easy finding of the hour of azimuth, 1624, in 4to; 2. The Art of Dialling, 1638, in 4to; 3. Posthumæ Fosteri, containing the description of a Ruler upon which are inscribed divers scales, 1652, in 4to; 4. Four
Fothergill. Treatises of Dialling, 1654, in 4to; 5. The Section altered, and other scales added, with the description and use thereof, 1661, in 4to; 6. Miscellanies, or Mathematical Lucubrations. Of the treatises in this collection some are written in Latin and others in English.
There were two other persons of this name who published mathematical works; William Foster, a disciple of Mr Oughtred, who taught in London; and Mark Foster, author of a treatise on trigonometry, who lived later than the former.