Charles Xavier Thomas de Colmar


Charles Xavier Thomas de Colmar of France produced in1820 the first mass produced calculator for which he received the Chevalier of the Legion of Honor. De Colmar conceived of the project while serving in the army.  The arithometer drew upon Leibniz's design through it use of stepped drum gears for calculation.  De Colmar improved upon Leiniz's design by reversing the operating function in the result registers thereby prolonging use without gear re-alignment.  Much like contemporary desktop computers, de Colmar's original arithometer occupied a whole desk and could not be moved by a single person.  It spurred on many rivals, eventually leading to quite sophisticated calculating machines that overcame the pitfalls of the stepped-drum design. Thomas received France's  for the product.


Copy of Patent papers

The History of Computing Project

Computer Museum of America

Photo Credits

de Colmar: IBM

Piano Arithometer: Robert Otnes, PhD