Blaise Pascal (1623–1662)

Blaise Pascal was born in Clermont-Ferrand, France. His parents were Antoinette Bégon and Étienne Pascal, a local magistrate and presiding judge of the tax court there. He had two sisters, Gilberte and Jacqueline. Their mother died in 1626, when Blaise was three, and a few years later the family moved to Paris. Étienne Pascal, also a mathematician and natural philosopher who was proficient in Latin and Greek, devoted himself to the education of his children, who all showed exceptional abilities. Although often ill and in pain, Blaise proved to be talented in mathematics and science from a young age. In 1640, at age 16. he published an essay on conic sections, Essai pour les coniques, which won praise as an important contribution to the relatively new field of projective geometry. Between 1642 and 1644, Pascal conceived and constructed a calculating device, known as the Pascaline, the world's first mechanical calculator. In 1646, Etienne fell and fractured his leg and seriously injured his hip; he received medical treatment from two brothers who were disciples of Jean du Vergier de Hauranne, abbé de Saint-Cyran and director of the abbey of Port-Royal in Paris. The abbé Saint-Cyran had introduced an austere moral and theological creed known as Jansenism and the whole Pascal family converted. Pascal became devoutly religious and his sister Jacqueline eventually became a Jansenist nun. Over the next few years, Pascal tested the theories of Galileo and of Evangelista Torricelli. In a famous experiment in 1648, he had his brother-in-law take barometric readings at various altitudes on the Puy-de-Dôme, the highest mountain in the Auvergne, so he could test Torricelli's ideas on atmospheric pressure. During this time, Pascal invented the syringe and the hydraulic press. The years 1651–1654 were another period of intense scientific work for Pascal, during which he composed treatises on the equilibrium of liquid solutions, on the weight and density of air, and on the arithmetic triangle. Together with Pierre de Fermat, he created the calculus of probabilities. Pascal had a carriage accident in November 1654 in which he narrowly escaped death, and considered this a summons to begin a new life in seclusion from the world. He entered the abbey of Port-Royal and remained there until his death at age 39 in 1662. The two works for which he is chiefly remembered, Lettres Provinciales (1657) and the Pensées (1658), date from the years of his life at Port-Royal. Pascal's contributions to science have been honored in a variety of ways. In 1972, Nicklaus Wirth named his new computer language Pascal. The Pascal (symbol Pa) is the unit of pressure designated by the International System of Units.