Farey's ellipsograph dated 1817 in mahogany case. An ellipsograph is used to draw ellipses, which consist of a combination of two circular motions. The drawing pencil is fixed in position in a central ring, which then revolves. At the same time, the
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
The earliest known dated slide rule, made by Robert Bissaker, which uses scales bound together with metal bands.
Harding's improved counter by Harding, Richardson, Rhodes and Co. Ltd., Leeds. Revolution counters were devised to keep a record of the operation of machinery.
Magic Brain' calculator made by Chadwick in tin and plastic, with stylus and instructions. C.1955. Very similar to the Exaxctus and other stylus calculators of the period, the Magic Brain could add, subtact, and multiply and duivide by repeated addit
Laundry tally board, English, of wood, brass and horn
Electronic Pocket Calculator by Isot, model Elka 101, c1976. Before the fall of the Iron Curtain in 1989, Bulgaria hasd one of the largest electronics industries in Eastern Europe. However in the 1970s they had to import the integrated circuits to co
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.
Stchoty (Russian form of Abacus), early 20th century. The stchety has horizontal rows of beads rather than vertical as in the Japanese abacus. It is specifically for counting rubles and kopeks. The lower three rows are for the kopeks. The rest positi
Set of Napier's bones, in wooden case with trade label of "J. Imison, Clock & Watch Maker, Optician, &c., No. 58 Hay-market, London", late 18th century. Napier's bones were invented in 1617 by Lord Napier of Murchiston, the inventor of logarithms, as