From the Writer's Almanac for June 19th http://app.info.americanpublicmediagroup.org/e/es?s=1715082578&e=20992&elq=78595e5b7b8b4154b41e17707fb84b13 It's the birthday of mathematician, physicist, and theologian Blaise Pascal ( books by this author ), born in Clermont-Ferrand, France (1623). A child prodigy, by the time he was 19 he had already perfected the first mechanical calculator for sale to the public. In the field of physics, he discovered that air has weight, and he conducted experiments to prove that vacuums could exist, which led him to formulate the hydraulic principle that "pressure exerted on a fluid in a closed vessel is transmitted unchanged throughout the fluid." This principle is used today in devices such as syringes, hydraulic presses, automobile brakes, and aircraft controls. In mathematics, he founded the theory of probabilities and developed an early form of integral calculus. He spent much of his life in conflict between science and