Scheutzian calculation engine

The Scheutzian calculation engine was a mechanical calculator built on the same difference engine principle as Charles Babbage's design, developed by the Swedish inventor Per Georg Scheutz beginning in 1834 with his son Edvard, who proposed a working metal version in 1837. Their completed 1843 model calculated series using five digit numbers and first order differences; a larger, improved version built between 1851 and 1853 handled fifteen digit numbers and fourth order differences, was shown at the 1855 Paris World's Fair, and was sold to the Dudley Observatory in Albany, New York, making it the first printing calculator ever sold. A second machine built to British government order followed in 1859, and the Scheutz engines stand as the first working proof that Babbage's difference engine principle could be built successfully, years before Babbage's own design was completed by others.