Torricelli, Evangelista 1608-47
Italian physicist and mathematician

Born probably in Faenza, in 1627 he went to Rome, where he devoted himself to mathematical studies. His Trattato del Moto (1641) led Galileo to invite him to become his literary assistant, and on Galileo's death he was appointed mathematician to the grand-duke and Galileo's successor as professor to the Florentine Academy. He discovered that, because of atmospheric pressure, water will not rise above 33 feet in a suction pump. To him are owed the fundamental principles of hydromechanics, and in a letter to Ricci (1644) he gave the first description of a mercury barometer or 'torricellian tube'. He greatly improved both telescopes and microscopes, and published a large number of mathematical papers.