1623-1662

French mathematician and physicist who proved that the mercury-column height in barometers depends on air pressure. In hydrostatics Pascal's principle (1654) provides the connection between the mechanics of fluids and mechanics of rigid bodies. His correspondence with Pierre de Fermat laid the foundations for probability theory and combinatorial analysis. Pascal also invented a calculating machine that by means of cogged wheels could add and subtract. Some of the principles involved are still used in mechanical calculators.