|Event Date:||Event Title:||Event Description:|
|18th Nov, 1387||The 1st calculating machine- ABACUS||It was 1st developed in the 13th century by the Chinese. It is still used today in a "modern version".|
|'Napier's Bones'||"John Napier, the inventor of logarithms, also invented this aid to calculation known as 'Napier's Bones'.The 'bones' consist of a set of rectangular rods, each marked with a counting number at the top, and the multiples of that number down their lengths. When aligned against the row of multiples as shown, any multiple of the top number can be read off from right to left by adding the digits in each parallelogram in the appropriate row. Multiplication is thus reduced to addition."|
|The Slide Rule||This was a joint effort by two Englishmen Edmund Gunter and the reverend William Oughtred. This slide rule consisted of two logarithmic scales that could be manipulated together for calculation. SLIDE RULE|
|The Pascaline||The Pascaline was possibly the first mechanical adding device actually used for a practical purpose. It was built by Blaine Pascal to help his father, Etienne Pascal, a tax collector, with the tedious activity of adding and subtracting large sequences of numbers.|
|Leibniz Stepped Drum||The famous German polymath, mathematician and philosopher, Gottfried Wilhelm Von Leibniz invented a machine able to perform the four basic arithmetical operations. It uses a special type of gear named Leibniz Wheel which is a cylinder with nine bar-shaped teeth of incrementing length parallel to the cylinder’s axis.|
|Calculators of th 18th Century.||There weren't many advancements made during the 18th century in regards to calulator development and portability. There were a few main ones: Stanhope's Machine 1775; POLENI'S MACHINE - Italy - 1709 1727</a>|
|Arithmometer||Charles Xavier Thomas was a French inventor and entrepreneur best known for designing, patenting and manufacturing the first commercially successful mechanical calculator called the Arithmometer.|
|Scheutz Difference Engine||The world's first printing calculator, the Scheutz Difference Engine was introduced around 1853. It was built by George Scheutz and his son Edvard, based on the work of their friend Charles Babbage who later became known as the "father of computing".|
|Pin Wheel Calculator||Start of period of development of commercially successful mechanical calculators. Frank Baldwin in the USA invents the pin-wheel calculator.|
|Bollee's Direct Muliplication Machine||Bollee was the first person to develop a machine capable of direct multiplication, The idea had originally been though of by a Spaniard, living in New York, called Ramon Verea,.
Bollee’s machine was one of the earliest of its type and was a direct multiplier with a built-in multiplication table
|Comptomer||Dorr E. Felt invents the Comptometer, the first succesfull key-driven adding and calculating machine. In 1886 he joined with Robert Tarrant to form the Felt & Tarrant Manufacturing Company which went on to make thousands of Comptometers .|
|Millionaire Calculator||Millionaire calculator introduced. It allowed direct multiplication by any digit - "one turn of the crank for each figure in the multiplier".|
|10 key adding machine||The Dalton adding-listing machine was the first of its type to use only ten keys - first 10-key add-lister.|
|Curta I||A stepped gear type calculator capable of the four functions, and more using special techniques. One of the few major innovations in mechanical calculators in the mid 20th century. HAND HELD|
|The Friden SRW||The Friden SRW was an imposing calculator weighing 42lbs. T MOST NOTABLE FOR BEING ABLE TO DO SQUARE ROOT function..|
|Madas 20BZS||Mechanical, electrically driven, stepped-gear calculator.
4 functions - addition, subtraction, multiplication, division.
The accumulator is at the top and can show a result to 20 places of decimals. The numbers entered can be to 10 places of decimals.
|Timespan Dates:||Timespan Title:||Timespan Description:|
|1900- 1975 Mechanical Calculators||Steady development of mechanical calculators - size reduction, electric motor drive, added features(eg. automatic multiplication & division).|