Leibniz Wheel (Stepped drum)
Die Staffelwalze (niem.)
Segment schodkowy (pl)
Stepped drum is constructed of coaxial cylinders that have 1 to 9 teeth. Numbers are entered by shifting toothed wheel relative to the drum, depending on the wheel's position it is rotated by 0 to 9 teeth (with each rotation of a drum).
Leibintz did not manage to solve the problem of carry between decimal positions.
Leibitz'
arithmometer
Carry was successfuly inplemented by Philip Hahn (1793-1790). In 1770 he constructed fully operational arithmometer, that was produced in Uffenheim, unfortunnately its very high price (20000 gulden, when Hahn's solar clock costed 8 gulden) did not let it gain wider pupularity.
Hahn's
arithmometer
First true commercial success was so called Thomas Arithmometer, constructed by French Charles Xavier Thomas de Colnmar in 1820. This machine was copied by many companies and produced over the period of more than 100 years.
