Leibniz Calculating MachineIn 1671 Gottfried Wilhelm von Leibniz (1646-1716) invented a calculating machine which was a major advance in mechanical calculating. The Leibniz calculator incorporated a new mechanical feature, the stepped drum — a cylinder bearing nine teeth of different lengths which increase in equal amounts around the drum. Although the Leibniz calculator was not developed for commercial production, the stepped drum principle survived for 300 years and was used in many later calculating systems.