Torricelli, Evangelista

Torricelli, Evangelista (āvänjālē`stä tōr-rēchĕl`lē), 1608–47, Italian physicist and mathematician. He was Galileo's secretary (1641–42) and his successor as professor of philosophy and mathematics at Florence. He invented the barometer (1643), called the Torricelli tube, and a microscope, and he improved the telescope.

---

Torricelli, Evangelista

(born Oct. 15, 1608, Faenza, Romagna—died Oct. 25, 1647, Florence) Italian physicist and mathematician, inventor of the barometer. He served as secretary to Galileo during the last three months of the latter's life and was appointed to succeed him at the Florentine Academy. Two years later, pursuing a suggestion by Galileo, he filled a glass tube 4 ft (1.2 m) long with mercury and inverted the tube into a dish. He observed that some of the mercury did not flow out and that the space above the mercury in the tube was a vacuum. After much observation, he concluded that the variation of the height of the mercury from day to day was caused by changes in atmospheric pressure. He never published his findings. His work in geometry aided in the eventual development of integral calculus.