Pascal's first calculating machine, 1632.
© Science Museum / Science & Society Picture Library
Pascal's first calculating machine, 1632. Replica made by E Rogron in 1926. Blaise Pascal (1623- 1662) was a French mathematician, physicist and philosopher who pioneered the theory of probability. The SI (the international system of standard scientific units) unit of pressure, or stress, the pascal (Pa) and a computer programming language were named after him.