Set of ivory Napier's bones 18th century, in wooden box. John Napier of Merchiston, invented both logarithms in 614 and his 'bones' in 1617, sets of rods with tables inscribed on them which allow the user to multiply by simply adding figures.
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 Brass sector 1720-1753 signed T Heath Fecit, decorated on hinge and legs with floral patterns. Sectors were used from the end of the 16th century until the mid 19th century to perform calculations involving proportion. They were inscribed w
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
A single surface glass vessel made by Alan Bennett in Bedford, 1995. It consists of three Klein bottles arranged in a column which when cut form a pair of five-twist Mobius strips. A Klein bottle is a surface which has no edges, no outside or inside