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.
Wire model of a 'cylindroid' by Howard Grubb, Dublin in brass glazed cylindrical case on a wooden base. The model was made on the instructions of Robert Stawell Ball who wrote the definitive work 'A treatise on the Theory of Screws' in 1900. Thomas G
A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle cut to form one single-twist Mobius strip. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed in three d
A single surface model made by Alan Bennett in Bedford, 1995. This 'way-in-way-out vessel' is equivalent to two Klein bottles, one inverted, sealed together back-to-back. When cut it forms two pairs of single twist Mobius strips. A Klein bottle is a
A single surface model made by Alan Bennett in Bedford, 1995. It consists of a parallel-sided coil with remote return tube with the inlet and singularity at the same end, which when theoretically cut gives a pair of 17-twist Mobius strips. A Klein bo
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.
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