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  2. Pinwheel calculator - Wikipedia

    en.wikipedia.org/wiki/Pinwheel_calculator

    In St. Petersburg, Russia, Wilgott Theophil Odhner invented his arithmometer in 1874 and in 1890 [7] it became the first pinwheel calculator to be mass-manufactured. Its industrial production started in Odhner's workshop: W.T. Odhner, Maschinenfabrik & Metallgiesserei and then moved to the Odhner-Gill factory (фабрика Однера ...

  3. Pascaline - Wikipedia

    en.wikipedia.org/wiki/Pascal's_calculator

    Pascaline (also known as the arithmetic machine or Pascal's calculator) is a mechanical calculator invented by Blaise Pascal in 1642. Pascal was led to develop a calculator by the laborious arithmetical calculations required by his father's work as the supervisor of taxes in Rouen . [ 2 ]

  4. Mechanical calculator - Wikipedia

    en.wikipedia.org/wiki/Mechanical_calculator

    For 40 years, [58] the arithmometer was the only mechanical calculator available for sale and was sold all over the world. By 1890, about 2,500 arithmometers had been sold [59] plus a few hundreds more from two licensed arithmometer clone makers (Burkhardt, Germany, 1878 and Layton, UK, 1883). Felt and Tarrant, the only other competitor in true ...

  5. Arithmometer - Wikipedia

    en.wikipedia.org/wiki/Arithmometer

    A 12-digit arithmometer sold for 300 francs in 1853, which was 30 times the price of a table of logarithms book and 1,500 times the cost of a first-class stamp (20 French cents), but, unlike a table of logarithms book, it was simple enough to be used for hours by an operator without any special qualifications. [26]

  6. Calculator - Wikipedia

    en.wikipedia.org/wiki/Calculator

    The Arithmometer, invented in 1820 as a four-operation mechanical calculator, was released to production in 1851 as an adding machine and became the first commercially successful unit; forty years later, by 1890, about 2,500 arithmometers had been sold [16] plus a few hundreds more from two arithmometer clone makers (Burkhardt, Germany, 1878 ...

  7. Orders of magnitude (pressure) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(pressure)

    This is a tabulated listing of the orders of magnitude in relation to pressure expressed in pascals. psi values, prefixed with + and -, denote values relative to Earth's sea level standard atmospheric pressure (psig); otherwise, psia is assumed.

  8. List of conversion factors - Wikipedia

    en.wikipedia.org/wiki/List_of_conversion_factors

    See Weight for detail of mass/weight distinction and conversion. Avoirdupois is a system of mass based on a pound of 16 ounces, while Troy weight is the system of mass where 12 troy ounces equals one troy pound. The symbol g 0 is used to denote standard gravity in order to avoid confusion with the (upright) g symbol for gram.

  9. Pascal (unit) - Wikipedia

    en.wikipedia.org/wiki/Pascal_(unit)

    The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is an SI coherent derived unit defined as one newton per square metre (N/m 2). [1]