Robertson's Rapid calculator, pat no. 5871,1910. Made by the Robertson Rapid Calculator Company of Glasgow, this was one of several large-scale ready reckoners to be developed in the first decade of the 20th century. This form of ready reckoner place
Kelvin's harmonic analyser, 1878. The machine was Invented by William Thomson, Lord Kelvin, (1824-1907), a pioneering Irish physicist. The harmonic analyser was designed to analyse graphical records of daily changes in atmospheric temperature and pre
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
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.
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
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
The 'Arithmetical Jewel' publicised by William Pratt in 1619. This instrument combines features of an abacus with those of pen reckoning. Numbers are put in by moving the flags to reveal dots. Sums are then worked out with a pen and paper.
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
Nine inch brass sector, by Adams; engraved "Improv'd and made by Geo. Adams, Mathm. Inst. Maker to His Royal Highness, George Prince of Wales, London", in fishskin case. Sectors were used in calculations involving proportion. They contain logarithmic
A single surface model made by Alan Bennett in Bedford, 1995. It consists of a Klein bottle cut to form two interlinked three-twist Mobius strips. A Klein bottle is a surface which has no edges, no outside or inside and cannot be properly constructed