On Display

    Gunner's callipers, early 18th century.

    Gunner's callipers by Thomas Wright, early 18th century. The callipers can be used as shown to measure the diameter of cannon balls, or with crossed arms to measure the bore of a cannon. The arms are inscribed with tables containing information relat

    Pascal's calculating machine, 1642.

    Replica made by E. Rognon, Paris of Blaise Pascal's first calculating machine of 1642, held by the Conservatoire National de Art et Metiers, Paris.The original machine was completed in 1642 when Pascal was only 19, to help his father in business. It

    Chuckrum board, Indian, late 19th century.

    Chuckrum board with 108 small coins.This board was used to count 100 small 'chuckrum' coins rapidly by spreading them over the surface to fill the holes.

    Kelvin's harmonic analyser, 1878.

    Kelvin's harmonic analyser, 1878. The machine was Invented by William Thomson, Lord Kelvin, (1824-1907), a pioneering Irish physicist. The harmonic analyser was designed to analyse graphical records of daily changes in atmospheric temperature and pre

    Arithmetical Jewel, 1619.

    The 'Arithmetical Jewel' publicised by William Pratt in 1619. This instrument combines features of an abacus with those of pen reckoning. Numbers are put in by moving the flags to reveal dots. Sums are then worked out with a pen and paper.

    Exchequer tally and foil, English, 1822.

    An exchequer tally dated 1822. The English Exchequer used tallies to record deposits from the mid-12th century until 1826. Notches show the amount paid; differently spaced notches standing for a penny, a shilling, £1, £20, £100 and £1000.

    Boxwood Coggeshall folding slide rule, 1720-1730.

    Boxwood Coggeshall rule, folding with slide, c. 1720-1730. Until the early 19th century slide rules were usually made for specific trades. This is a type of carpenter's rule.

    Timetable or rent rule, 1850-1860.

    Timetable or rent rule for calculating the number of weeks for storage charges, as used by the dock companies, by Dring and Fage, Tooley Street, London, c. 1850-1860. The rule allows the number of weeks to be read off between two dates up to two yea

    Chinese abacus or Suan Pan, 19th century.

    Chinese abacus, or suan-pan, 19th century

    Bavarian reckoning cloth, German, 16th century.

    Replica of a Bavarian counting cloth, 16th century. The original cloth is preserved at the Bavarian National Museum in Munich. Reckoning cloths were used as portable substitutes for counting boards. The letters on the cloth stand for various denomina