Mathematician and physicist; b. at Perugia, Italy, 1577; d. at
Rome, 1644. He was destined by his parents for the service of
the Church and entered the Order of St. Benedict, at Monte
Cassino. There he became abbot, and in 1640 he was transferred
to the Abbey of San Benedetto Aloysio. He was specially
interested in the mathematical sciences and their application to
hydraulics. Galileo, his teacher, and Toricelli, one of his
pupils, speak very highly of his scientific attainments, and
both of them frequently asked his advice. In 1623 Urban VIII
invited him to Rome and later appointed him chief mathematician
to the pope and public professor of mathematics in the
University of Rome. In 1625 he was sent with Monsignore Corsini
to study the disorders occasioned by the waters of the Romagna,
and to propose a remedy. Here he completed his important work on
the "Mensuration of Running Water", in which he developed the
important relations, that the speed of a current varies
inversely as the area of its cross section,