Comptator

Comptator - 1909

This compact hand held, rack driven adding machine is a refinement of the Rapid Computor Adding Machine. This unit, which came in nine or thirteen place models offered an adjustable point indicator, an adjustable decimal point indicator in both the entry and result mechanisms, steel margins with complimentary figures for subtraction, and a reliable release key.

Blaise Pascal (1623 - 1662) was the son of a tax collector in Rouen, a small town in southern France. Gifted in mathematics and bothered by the tedium of adding long columns of numbers, Pascal was 19 years old when he designed the " Pascaline" in 1642. A stylus was placed in an indentation on the dials (surface) and the dial was rotated clockwise. Gears underneath the surface contained a mechanism for a carry; subtraction was effected using complimentary addition. "Modern" versions of Pascal's machine are shown in Lightning Calculator and the Comptator.