Mathematics

Six inch silver sector signed "Ramsden, London" with attached set square, late 18th century. Sectors were used from the end of the 16th century until the mid 19th century for calculations involving proportion. They were ingraved with logarithmic and

• Six inch silver sector, late 18th 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

• Replica quipu, South American, c 15th century.

Wine diagonal, a type of gauging rod, by J.Stutchbury, 1797-1826. These were used by Excise Officers together with slide rules to calculate the volume of wine in wine casks, and thence the duty payable. Until 1826 the volume of a wine gallon was diff

• Wine diagonal, 1797-1826.

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.

• Protractor by Dollond, late 18th century

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

• Navigation slide rule, c.1800.

A single surface model made by Alan Bennett in Bedford, 1995. It is a toroid Klein bottle with disguised pierce which when cut produces a pair of single-twist Mobius strips. A Klein bottle has no edges, no outside or inside and cannot be properly con

• Klein bottle, 1995

Single surface models made by Alan Bennett in Bedford, 1995. Three toroid single surface vessels, one with the loop inside the torus, one with a narrow loop outside and one with a wider loop outside. All can be cut to produce a pair of single-twist M

• Klein bottles, 1995

Consul' the Educated Monkey. A mathematical toy calculator patented by William Robertson in 1916 and made by the Educational Novelty Company of Dayton, Ohio, USA. When each of the monkey's feet are moved to point at two numbers, the monkey's hands m

• Consul' the Educated Monkey

Japanese soroban or abacus with 13 columns, each with 5 beads below the bar and one above.This represents an intermediate form between the original Chinese abacus and the modern Japanese type. This arrangement was common from the late 19th century u

• Japanese abacus, c 1900.

Stylus-operated Indian currency adder, wooden backboard with handmade varnished card face inscribed 'R.G.W. 24.2.12'. The GEM calculator was originally patented in 1890 as a simple device for the addition of English money. Numbers are added by insert

• GEM calculator converted for Indian currency, 1912.