Replica of Schickard's Calculating Clock


In 1623 and 1624, Wilhelm Schickard, in letters that he sent to Kepler, reported his design and construction of what he referred to as an "arithmeticum organum" (arithmetical instrument) that he has invented, but which would later be described as a Rechenuhr (calculating clock). The machine was designed to assist in all the four basic functions of arithmetic (addition, subtraction, multiplication and division). The machine could add and subtract six-digit numbers, and indicated an overflow of this capacity by ringing a bell. The adding machine in the base was primarily provided to assist in the difficult task of adding or multiplying two multi-digit numbers. To this end an ingenious arrangement of rotatable Napier's bones were mounted on it. It even had an additional "memory register" to record intermediate calculations. Schickard hired a professional, a clockmaker named Johann Pfister to build a finished machine, but it was destroyed in a fire. Schickard abandoned his project soon after. He and his entire family were wiped out in 1635 by bubonic plague during the Thirty Years War.


Size: 4200px × 3150px
Photo credit: © Photo Researchers / Alamy / Afripics
License: Licensed
Model Released: No

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