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Calculating Clock (1623)

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Wilhelm Schickard's Calculating Device: 
The Calculating Clock

Replica of 1623 Calculating Clock

This six-digit machine could add, subtract, multiply and divide.  A set of Napier’s Bones was attached to the Clock in order to perform the mathematical operations. It used a bell to indicate overflow (when the calculation produced a result too large for the machine to represent).  Schickard himself did not actually build the machine, but made design plans and wrote about how it would work, were it constructed.  Schickard’s plans have been through a lot.  The plans for the calculating clock were lost in the war, found once the war ended, lost in the next war, then rediscovered again by the same man.  The machine was finally constructed in 1960 and found to work just as Schickard had said it would.  The calculating clock is considered the first calculating device because it didn’t depend on the operator manually moving the device (as in the case of the abacus or Napier’s Bones) but rather the device moves itself mechanically.

German Wilhelm Schickard (1592-1635), like many men of his time, had many career interests.  He was an astronomer, mathematician, linguist, and Lutheran minister.  In 1613 he became a Lutheran minister and served as that until 1619 when he became the professor of Hebrew at the University of Tübingen.  Starting in 1631, he taught astronomy at the university.  Schickard also made maps that were far more advanced than the ones available at the time.  In addition to these numerous skills, Schickard was also known for his engravings in both wood and copperplate.

Wilhelm Schickard

Jessica Carlson