Schickard’s calculating clock

Schickard’s calculating clock (1623). The “calculating clock” of Wilhelm Schickard is considered to be the first mechanical calculating machine. It comprises two separate sections, an arithmetic unit for addition and subtraction (below) and cylinders for multiplication and division (above) that func-tion similarly to Napier’s bones. The six rotating knobs (at the top) serve for inputting up to 6-place multiplicands. The six (vertically mounted) dials (below) acquire the values for the addition and subtraction mechanism. The numerals are represented by counter wheels (© Deutsches Technikmuseum, Berlin).