Blaise Pascal

Blaise Pascal (1623–1662) demonstrated astonishing genius from childhood, proving Girard Desargues' theorem on conic sections at age sixteen. To help his father, a royal tax commissioner, Pascal spent three years inventing and building the Pascaline in 1642—the world's first commercial mechanical calculating machine.

In fluid dynamics, his barometric experiments atop the Puy-de-Dôme volcano proved that atmospheric pressure diminishes with altitude and that vacuums exist in nature (formulating Pascal's Law of hydraulic pressure). In 1654, his historic correspondence with Pierre de Fermat on gambling problems laid the mathematical foundations of probability theory.