Birthday of Wilhelm Schickard (1592)

Wilhelm Schickard built the first mechanical calculating machine in 1623 — preceding Pascal's Pascaline by 19 years. Schickard's 'Calculating Clock' added and subtracted 6-digit numbers automatically, with a bell that rang when numbers overflowed. He built it as a gift for his friend Johannes Kepler, to speed astronomical calculations. The machine was destroyed in a fire and his design was rediscovered only in 1957 in a letter to Kepler. A working replica was built in 1960. Schickard, Kepler, and Pascal form a chain: mathematics animating machines to liberate human thought.