On Display

Henrici's harmonic analyser, No 3, 1894.

Harmonic analyser designed by O.Henrici, made by G. Coradi, 1894. Harmonic analysers were designed to break down a complex wave, such as a sound wave, into its fundamental and harmonic components. This one uses the motions of three glass spheres whic

 
The 'Multiplicateur Enfantin' ready reckoner, c 1880.

Automatic calculator: Chambon's "Multiplicateur Enfantin". The device shows multiplication tables up to 50 times 28.

 
Quipu, South American, c 15th century.

Replica of a quipu made from an original held at the Museum of Natural History, New York, in 1974. Quipus were used by the Incas during the 15th and early 16th centuries as records of all types of accounts. It was discovered in the early 20th century

 
Gunnery callipers, French, 17th century.

Callipers, used for artillery purposes, French, 17th century. Callipers were used to measure the diameter of cannon balls and the bores of cannons. This example also containd scales for artillery calculations

 
GEM calculator, 1890.

Gem' calculating machine, J.Guthrie's patent No 15062, 1890. The GEM calculator is a simple device for the addition of English money. Numbers are added by inserting a stylus against the figure and pulling downward.

 
Klein bottle, 1995.

A single surface model made by Alan Bennett in Bedford, 1995. It consists of three Klein bottles set inside each other sharing a common loop. When cut this gives a pair of single-twist Mobius strips. A Klein bottle has no edges, no outside or inside

 
Model depicting face-centred cubic packing, 1975.

Model to show face-centre cubic packing made of ping-pong balls.1975. This model imitates a stuctural form found in crystals.

 
Klein bottle, 1995.

A single surface model made by Alan Bennett in Bedford, 1995. It consists of a parallel sided coil with loops piercing the return tube which when theoretically cut gives a pair of 13-twist Mobius strips. A Klein bottle has no edges, no outside or ins

 
Rectangular protractor, late 18th century.

Rectangular protractor in brass, engraved "Dollond, London", late 18th century.As well as the usual angular scale the instrument contains a diagonal scale for plotting distances on a map or plan.

 
A sectioned Sinclair Executive pocket calculator, 1972.

The Sinclair Executive Electronic Pocket Calculator (cutaway for exhibition) was the first electronic pocket calculator that could really fit into a pocket. Clive Sinclair (b. 1940) was able to achieve this by reducing the power input demanded by the