Gregory Of St. Vincent

, a Flemish geometrician, was born at Bruges in 1584, and became a Jesuit at Rome at twenty years of age. He studied mathematics under the learned Jesuit Clavius. He afterward became a reputable professor of those sciences himself, and his instructions were solicited by several princes he was called to Prague by the emperor Ferdinand II. and Philip IV. king of Spain was desirous of having him to teach the mathematics to his ion, the young prince John of Austria. He was not less | estimable for his virtues than his skill in the sciences. His well-meant endeavours were very commendable, when his holy zeal, though for a false religion, led him to follow the army in Flanders one compaign, to confess the wounded and dying soldiers, in which he received several wounds himself. He died of an apoplexy at Ghent, in 1667, at eighty-three years of age.

As a writer, Gregory of St. Vincent was very diffuse and voluminous, but he was an excellent geometrician. He published, in Latin, three mathematical works, the principal of which was his “Opus Geometricum Quadratures Circuli, et Sectionum Coni,” Antwerp, 1647, 2 vols. folio. Although he has not demonstrated, in this work, the quadrature of the circle, as he pretends to have done, the book nevertheless contains a great number of truths and important discoveries; one of which is this, viz. thai if one asymptote of an hyperbola be divided into parts in geometrical progression, and from the points of division ordinates be drawn parallel to the other asymptote, they will divide the space between the asymptote and curve into equal portions; from whence it was shewn by Mersenne, that, by taking the continual sums of those parts, there would be obtained areas in arithmetical progression, adapted to abscisses in geometrical progression, and which therefore were analogous to a system of logarithms. ¹