Wilhelm Schickard

Wilhelm Schickard (22 April 1592 to 23 or 24 October 1635) was a German professor of Hebrew and astronomy at the University of Tübingen, where he had studied and where he taught biblical languages, astronomy, mathematics and surveying. He is remembered for a calculating clock that he described to Johannes Kepler in two letters of 1623 and 1624. It was meant to assist all four basic functions of arithmetic, added and subtracted six digit numbers and rang a bell on overflow, and combined an adding machine with a set of rotating Napier bones for multiplication. A clockmaker named Johann Pfister was to build a finished machine, but it was destroyed in a fire before delivery. The drawings became widely discussed after Franz Hammer announced them in 1957 as predating Pascal by twenty years, though later study found that the design had flaws in its single tooth carry mechanism. Schickard also made far more accurate maps, engraved wood and copper, and died of bubonic plague in 1635. A lunar crater and the Wilhelm Schickard Institute for Computer Science at Tübingen carry his name.