1623 – Invention of Calculating Clock… Sort of

Moving on with history of computing devices. In 1623, a Calculating Clock was first invented by Wilhelm Schickard. Wilhelm Schickard (22 April 1592 – 24 October 1635) was a German professor of Hebrew and Astronomy.

Calculating Clock Replica
Schickard’s Mechanical Clock Replica – picture by Herbert Klaeren

There is plenty of debate on the subject of Pascal versus Schickard when it comes to the first calculating clock – and while many believe that Pascal is an official the inventor of such device, there is undeniable evidence that Schickard should be recognized as the original inventor, since Dr. Franz Hammer, a biographer of Johannes Kepler, claimed that the drawings of a calculating clock, predating the public release of Pascal’s calculator by twenty years, had been discovered in two unknown letters written by Schickard to Johannes Kepler in 1623 and 1624.

After a thorough examination of Schikard’s drawings that were published at least once per century starting from 1718, it was evident that his machine was not complete and required additional wheels and springs and that it was designed around a single tooth carry mechanism that didn’t work properly when used in calculating clocks. Nevertless, Dr. Hammer believed that Pascal is not the original inventor of the mechanical calculating clock.

Schickard’s machine was the first of five unsuccessful attempts of designing a direct entry calculating clock in the 17th century, including the designs of Burattini, Morland and Grillet). Schickard’s work had no impact on the development of mechanical calculators.