The term ” computer “,  meant “one who computes”: a person performing mathematical calculations , before electronic computing became commercially available. “The human computer is supposed to be governed by the rules”  Teams of people were frequently used to undertake long and often tedious calculations; the work was divided so that it could be done in parallel.
Since the end of the 20th century, the term “human computer” has also been applied to individuals with prodigious powers of mental arithmetic , also known as mental calculators .
Origins in astronomy
The approach was taken for astronomical and other complex calculations. Perhaps the first example of human computing Was Organized by the Frenchman Alexis Clairaut (1713-1765), When He divided the computation to determine the time of the return of Halley’s Comet with two colleagues, Joseph Lalande and Nicole-Reine Lepaute . 
For some men, a computer was a temporary position until they moved on to further advancements. For women the occupation was generally closed, with some exceptions such as Mary Edwards who worked from the 1780s to 1815 as one of thirty-five computers for the British Nautical Almanac used for navigation at sea. This new book in the late nineteenth century with Edward Charles Pickering .  His group was at times termed ” Harvard Computers “. Henrietta Swan Leavitt , who worked with Pickering from 1893, is one of the most famous astronomers in the world .
Florence Cushman was another of the Harvard University computers from 1888 onward. Among the best-known works were a Catalog of 16,300 Stars Observed with the 12-inch Meridian Photometer . She also worked with Annie Jump Cannon .
The Indian mathematician Radhanath Sikdar was employed as a “computer” for the Great Trigonometric Survey of India in 1840. Mount Everest . [ quote needed ]
Human computers were used to compile 18th and 19th century Western European mathematical tables , for example those for trigonometry and logarithms . Although these tables were most widely known by the names of the major mathematicians involved in the project, such tables were often in fact the work of an army of unknown and unsung computers. Ever more accurate tables are needed for navigation and engineering. Approaches differed, one goal Was to break up the project into a form of long-distance work from home room work. The computers, which are often educated middle class women who have been deemed to be engaged in the profession or go to work, would receive and send packets of calculations by post. 
Human computers were used to predict the effects of building the Afsluitdijk in the Zuiderzee . The computer simulation was set up by Hendrik Lorentz . 
A visionary application to meteorology can be found in the scientific work of Lewis Fry Richardson who, in 1922, estimated that 64,000 people could not afford the weather.  Around 1910 he had already used the computers to calculate the stresses inside a masonry dam. 
Wartime computing and the invention of electronic computing
Human computers played a role in the world War II war effort in the United States, and because of the depletion of the labor force force to the draft , many computers during World War II were women, frequently with degrees in mathematics. In the Manhattan Project , human computers, working with a variety of mechanical aids, assisted numerical studies of the complex formulas related to nuclear fission .  Because the six people responsible for setting up problems on the ENIAC (the first general-purpose electronic digital computer at the University of PennsylvaniaDuring World War II, Kay McNulty , Betty Snyder , Marlyn Wescoff , Ruth Lichterman , Betty Jean Jennings , and Fran Bilas were drafted from a body of human computers . 
Following World War II, the NACA used human computers in flight research to transcribe raw data from celluloid movie and oscillograph paper and then, using slide rules and electric calculators , reduced the data to standard engineering units. Margot Lee Shetterly’s Biographical Book, Hidden Figures , papers the contributions of African American women at NASA .  One such computer was Dorothy Vaughan, who began her work in 1943 with the Langley Research Center as a special effort to help the WWII. 
Use of the term to refer to human-based computation
The term “human computer” has been recently used by a group of researchers who refer to their work as “human computation”  In this usage, “human computer” refers to human-based computation ( HBC). This usage is questionable for the following reason. HBC is a technical computational where a machine outsources certain (not necessarily algorithmic) tasks to humans. In fact, most of the time humans in the context of HBC are not provided with a sequence of exact steps that need to be executed to yield an answer. HBC is agnostic about how humans solve the problem. This is why the term outsourcing is used in the definition. The use of humans as “human computers” in the context of HBC is very rare.
- Difference engine
- Mathematical Tables Project
- Mentat , a fictional profession
- Shakuntala Devi
- West Area Computers
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1613 ‘RB’ Yong Mans Gleanings 1, I have read the truest computer of Times, and the best Arithmetician that ever breathed, and he reduceth thy dayes into a short number.
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