Set of mathematical drawing instruments by G.Adams, in Sheraton case, oak and mahogany, mid 18th century. The case contains a sector, parallel ruler, pair of callipers, rectangular protractor, curve drawing instrument and compasses and dividers.
Gunners callipers, 6 inch by H.Gregory, brass 18th century. These callipers ere used for measuring the diameter of cannon balls, or by crossing the arms, the bore of a cannon..
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
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
Little Professor' calculator, children's working educational toy / game, 1980. Electronic calculators were now low cost available items which could be targetted at children and those with straightforward requirements. This example was exhibited in th
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
Exactus stylus-operated adding and subtracting device, with swivelling half plate for add and subtract options, marked "Mini-Add Made in England", c. 1950. The Exactus is one of several simple stylus-operated calculators to have been popular in the
Single surface models made by Alan Bennett in Bedford, 1995. Four small Klein bottles (left to right): i) one loop relating to the single-twist Mobius strip, ii) two loop relating to the three-twist Mobius strip, iii) three loops relating to the five
A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle cut to form one four-twist band. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed in three dimensions.
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 di