Evangelista Torricelli

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Evangelista Torricelli, portrait by an unknown artist.

Evangelista Torricelli (October 15, 1608 – October 25, 1647) was an Italian physicist and mathematician.

Born in Rome, Torricelli soon moved to Faenza, then part of the Papal States. He was left fatherless at an early age. He was educated under the care of his uncle, a Camaldolese monk, who in 1627 sent him to Rome to study science under the Benedictine Benedetto Castelli (1577-1644), professor of mathematics at the Collegio della Sapienza in Pisa. Torricelli died a few days after having contracted typhoid fever.

The asteroid (7437) Torricelli was named in his honor.

Torricelli's work in physics

After Galileo's death Torricelli was nominated grand-ducal mathematician and professor of mathematics in the Florentine academy. The discovery of the principle of the barometer which has perpetuated his fame ("Torricellian tube", "Torricellian vacuum") was made in 1643. The torr, a unit of pressure is named after him.

Torricelli's work in mathematics

Torricelli is also famous for the discovery of the Torricelli's trumpet or horn whose surface area is infinite, but whose volume is finite. This was seen as an "incredible" paradox by many at the time (including Torricelli himself, who tried several alternative proofs), and prompted a fierce controversy about the nature of infinity, involving the philosopher Hobbes. It is supposed by some to have led to the idea of a "completed infinity".

Torricelli was also a pioneer in the area of infinite series. In his De dimensione parabolae of 1644, Toricelli considered a decreasing sequence of positive terms [a_0, a_1, a_2 \cdots] and showed the corresponding telescoping series [(a_0-a_1) + (a_1-a_2) + \cdots] necessarily converges to [a_0-L], where L is the limit of the sequence, and in this way gives a proof of the formula for the sum of a geometric series.

See also

• Torricelli's equation

References

• Weil, André, Prehistory of the Zeta-Function, in Number Theory, Trace Formulas and Discrete Groups, Aubert, Bombieri and Goldfeld, eds., Academic Press, 1989
• de Gandt, l'oeuvre de Torricelli,ed Les Belles Lettres,1987,ISBN 2-252-62032-X

External links

• John J. O'Connor and Edmund F. Robertson. [] at the MacTutor History of Mathematics archive.

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