Never enough knowledge
This working Psion cost £4 at the local car boot sale. Because of its early place in the PDA/organiser timeline, the Organiser II, launched in 1986 has historical significance as part of the shift from simple calculators toward personal digital assistants. The CM version is the entry-level model of the Organiser II family. The CM…
An Abacus consists of beads or stones on rods or wires each representing a numerical value. Beads are manipulated to perform addition, subtraction, multiplication and division. The one shown here has nine beads on each rod. A horizontal beam divides the rods into an upper and a lower section such that one bead on each rod is…
Scale rules are tools used to measure distances on scale drawings and physical models, allowing for precise calculations of actual object dimensions based on the drawing’s scale. A scale rule indicates the relationship between a drawing’s dimensions and the actual object’s dimensions, so a scale of 1:50 means that 1 unit on the drawing represents 50…
A slide calculator is a type of small, hand-held mechanical calculator, primarily for adding and subtracting. The example shown opposite features parallel toothed metal strips within a metal envelope and a side-mounted stylus to operate it. The Addiator-Gesellschaft company, based in Berlin, Germany, was a prominent manufacturer, and the term “Addiator” is often used as…
This Brunsviga model 18RK serial 34-113557 was obtained at a local car boot sale for £25. The machine I purchased was in full working order. Its serial number indicated that it was manufactured around 1954 with a retail price list of DM710. It is a type of pinwheel calculator which utilises rotating wheels (pinwheels) with…
Alexander George Thornton founded his business in 1880 in Manchester, took over the Precision Instrument Co in 1901 and in 1967 changed the name of the company to British Thornton. The firm grew to become one of the largest manufacturers of drawing instruments and slide rules in Britain. PIC continued to be used by Thornton…
Cylindrical slide rules exist in two designs – one with a logarithmic scale wrapped in a spiral around the outside of a cylinder (such as the Otis King and Fuller’s rule), the other in the form of bars (Thatcher). Both types provide a longer scale than a straight or circular rule, which can lead to…
Samuel Pepys, the ‘Father of the Modern Navy’, recorded in his Diary 14th April, 1663 ‘I walked to Greenwich, studying the slide rule for measuring of timber, which is very fine‘. It was a Coggeshall slide rule to help measure the dimensions, surface area, and volume of timber having the form of a folding carpenter’s measuring…
This working model was obtained from a local car boot sale. The TI-5200 was a desktop calculator introduced by Texas Instruments in January 1977 priced at around $150 USD. The main features are: The concept of integrating electronic circuits into a single device was first proposed by British engineer Geoffrey Dummer in 1952. However, it…