Blaise Pascal (19.06.1623-19.08.1662) was a French mathematician, physicist and philosopher. Born in Clermont-Ferrand. He was educated at home. From childhood he showed outstanding mathematical ability, and at the age of 16 formulated one of the fundamental theorems of projective geometry (Pascal's theorem).
His physical research was mainly in hydrostatics, where in 1653 he formulated its basic law, according to which pressure on a liquid is transmitted by it uniformly and without change in all directions — Pascal's law (this property of liquids was known to his predecessors too), and established the principle of operation of the hydraulic press. He rediscovered the hydrostatic paradox, which became widely known thanks to him. He confirmed the existence of atmospheric pressure by repeating in 1646 Torricelli's experiment with water and wine. He expressed the idea that atmospheric pressure decreases with height (on his suggestion an experiment was carried out in 1647 which showed that at the top of a mountain the level of mercury in the tube is lower than at its foot), demonstrated the elasticity of air, proved that air has weight, and discovered that the readings of a barometer depend on the humidity and temperature of the air, and that it can therefore be used to predict the weather. He invented a calculating machine (1642–44). The unit of pressure, the pascal, is named after him.