# Mathematician:Evangelista Torricelli

## Mathematician

Italian physicist and mathematician, best known for inventing the barometer.

Disciple of Galileo.

Gave his name to Torricelli's Law.

Studied the properties of the figure in solid geometry known as Gabriel's horn, also now known as Torricelli's trumpet. Discovered in $1643$ that it has finite volume.

Used an improved form of Bonaventura Francesco Cavalieri's method of indivisibles.

Discovered in $1644$ the area of the cycloid.

Discovered in $1645$ the exact length of the inner portion of the logarithmic spiral.

Possibly the first to notice the relationship between differential calculus and integral calculus now recognised as the Fundamental Theorem of Calculus.

The first to understand air pressure and the nature of a vacuum.

Close friend of Bonaventura Cavalieri.

Corresponded with Marin Mersenne and Gilles Personne de Roberval in Paris.

A member of the informal Académie Parisienne.

## Nationality

Italian

## History

- Born: 15 Oct 1608, Faenza, Romagna (now Italy)
- 1642: Assistant and secretary to Galileo in his last days
- Died: 25 Oct 1647, Florence, Tuscany (now Italy)

## Theorems and Definitions

- Torricelli's Law
- Torricelli's Equation
- Fermat-Torricelli Point (with Pierre de Fermat), also known as a Fermat Point or a Torricelli Point
- Torricelli's Trumpet
- Torr (unit of pressure)

Results named for **Evangelista Torricelli** can be found here.

Definitions of concepts named for **Evangelista Torricelli** can be found here.

## Publications

- 1644:
*Opera Geometrica*

## Critical View

*To us his incredible genius seems almost miraculous.*

## Sources

- John J. O'Connor and Edmund F. Robertson: "Evangelista Torricelli": MacTutor History of Mathematics archive

- 1972: George F. Simmons:
*Differential Equations*... (previous) ... (next): $1$: The Nature of Differential Equations: Miscellaneous Problems for Chapter $1$: Footnote to Problem $7$ - 1991: David Wells:
*Curious and Interesting Geometry*... (previous) ... (next): A Chronological List Of Mathematicians - 1992: George F. Simmons:
*Calculus Gems*... (previous) ... (next): Chapter $\text {A}.15$: Torricelli ($\text {1608}$ – $\text {1647}$) - 1992: David Wells:
*Curious and Interesting Puzzles*... (previous) ... (next): Henry van Etten