TORRICELLI, EVANGELISTA, a celebrated Italian mathematician and philosopher, was born at Piancaldoli in the Romagna, Italy, Oct. 15,1608. He was brought up by n uncle who resided at Faenza, and who put him under the tuition of the Jesuits. When 20 years old, he was sent to Rome, and there devoted himself to mathematical studies. Galileo's theories on force and motion, which had been published a short time before, especially engaged his attention, and led to his publishing a Trattato del Moto. (1643), a meritorious work, but containing few new discoveries of consequence. The publication of fais work led to his being invited by Galileo to visit him; and on the old philosopher's death, three months afterward, he was appointed to succeed Galileo in the chair of philosophy and mathematics at Florence. Here he resided till his death in 1647. The discovery which will preserve Torricelli's name through all ages was the in terpretation of the previously known fact, that water will rise in a suction pump only to the height of about 32 feet. The fact that water could be raised in a pump was ex
pressed by the empirical law, that " nature abhors a vacuum," and after the limit of 32 ft. was ascertained, the law was modified accordingly by Galileo. Torricelli wishing to perform this experiment more conveniently, employed mercury, and found that nature's abhorrence of a vacuum varied for different fluids, and was represented by a column of fluid in height inversely proportional to its specific gravity; here, then, was an additional fact of importance, containing the clue to the mystery, and Torricelli was not long in hitting ou the idea that the column of fluid was sustained by the pressure of the atmos phere on the open surface of fluid. See BAROMETER. Torricelli also effected the quad. rature of the cycloid, but in this was ;:nticipated by Roberval.