On Display

    Navigation slide rule, c 1800.

    A 2 foot boxwood slide rule for navigators, c.1800. 'Sliding Gunters' , or navigator's rules with a slide are comparatively rare, as most navigators preferred to stick with the ordinary 'Gunter' scale based on the combination of trigonometric, logari

     
    Klein bottle, 1995.

    A single surface model made by Alan Bennett in Bedford, 1995. It consists of a sphere with three interlinked loops the equivalent of three interconnected Klein bottles. A Klein bottle has no edges, no outside or inside and cannot be properly construc

     
    Napier's Bones, c 1690.

    Set of Napier's bones in boxwood, in a boxwood case. John Napier (1550-1617), discoverer of logarithms, also created this popular calculating tool known as Napier's cylindrical 'rods' or 'bones'. Napier's bones reduced muliplication to a sequence of

     
    Brunsviga calculating machine, 1892.

    Brunsviga calculating machine with lid, no262. c.1892. This barrel calculating machine represents the Brunsviga in its earliest form. Barrel calculating machines were smaller, lighter and easier to operate than Arithmometers. The machine performs mu

     
    Klein bottle, 1995.

    A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle with coiled inlet tube, or jacketed coil with singularity and entrance at opposite ends, which when theoretically cut gives a pair of 19-twist Mobius strips.

     
    'Addiator' calculating machine, c 1924.

    Addiator' decimal adding machine with stylus and pencil on metal stand. Made by the Addiator-Gesellshaft Company of Berlin, Germany, the 'Addiator' was a relatively late mechanical calculator. It uses a chain mechanism, a stylus to add or subtract an

     
    Exactus stylus-operated adding and subtracting device, 1955-1965.

    Exactus stylus-operated adding and subtracting device, with swivelling half plate for add and subtract options, marked "Mini-Add Made in England", c. 1950. The Exactus is one of several simple stylus-operated calculators to have been popular in the

     
    French sector, 1751-1774.

    Brass French sector by Canivet, Paris, 1751-1774. French sectors are less complicated than English sectors. They are also used for calculations involving proportions of length, area and volume.The lines radiate from the centre of the hinge.

     
    Klein bottle, 1995.

    A single surface model made by Alan Bennett in Bedford, 1995. It consists of a parallel sided coil with one piercing of the return tube which when theoretically cut gives a pair of 15-twist Mobius strips. A Klein bottle has no edges, no outside or in

     
    Mechanical counting device, c 1900.

    Mechanical counting device, c 1900. Devices for counting the revolutions or repetitive actions of machines were developed from the mid 19th century.