Ready reckoner, boxwood weighted with brass, for gross and tare weights of ship's cargoes, engraved "Robert Ludgate, Custom House, London, 1807". Tare is the weight of the packaging or container. Scales are given for finding the gross weight if the
Boxwood Coggeshall rule, folding with slide, c. 1720-1730. Until the early 19th century slide rules were usually made for specific trades. This is a type of carpenter's rule.
Single surface glass vessel made by Alan Bennett in Bedford, 1995 The triple loop Klein bottle when cut gives a pair of five-twist Mobius strips. A Klein bottle is a surface which has no edges, no outside or inside and cannot properly be constructe
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
A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle with coiled inlet tube, or jacketed coil with singularity and entrance at opposite ends, which when theoretically cut gives a pair of 19-twist Mobius strips.
Timetable or rent rule for calculating the number of weeks for storage charges, as used by the dock companies, by Dring and Fage, Tooley Street, London, c. 1850-1860. The rule allows the number of weeks to be read off between two dates up to two yea
Two gilt bronze "arithmetical medals" sold by J.Maddux at the "Hand and Pen", Brook Street, Holbourn, c. 1753. The medals are inscribed with the multiplication tables up to 10 on one side and the 12 times table on the other. They indicate the relativ
A circular slide rule, made by John Brown, with two brass radial arms and an stronomical quadrant engraved on the back. A spiral slide rule affords a long and therefore accurate logarithmic line in a small amount of space. The potential of spiral rul
Chinese abacus, or suan-pan, 19th century
Replica of a Bavarian counting cloth, 16th century. The original cloth is preserved at the Bavarian National Museum in Munich. Reckoning cloths were used as portable substitutes for counting boards. The letters on the cloth stand for various denomina