Editing Comptometer (section)

==History==
[[Image:EarlyComptometerMachine.png|thumb|left|<div align="center">An early machine (1887)</div>]]

===Origins===
[[Image:Macaronibox.jpg|thumb|right|<div align="center">The macaroni box (1885)</div>]]
The comptometer is the direct descendant of the key-driven machine of Thomas Hill<ref>[https://patents.google.com/patent/US18692 Hill's Arithmometer patent]</ref> patented in the United States in 1857 and of the [[Pascaline]] invented by [[Blaise Pascal]] in France in 1642.  By just replacing the input wheels of the Pascaline by the columns of keys of Hill's machine, the comptometer was invented. Addition is performed exactly the same way, and both the Pascaline and the Comptometer make use of the [[Method of complements|9's complement]] method for subtraction, but in the case of the comptometer it is the operator who must choose the right keys for the [[subtrahend]] (each key has its 9's complement written in miniature letter next to it).

===The first comptometers===
[[Dorr Felt]] began his work on the comptometer in 1882<ref>{{cite book|last1=Cutter|first1=William Richard|title=American Biography: A New Cyclopedia|date=1931|publisher=Pub. under the direction of the American historical society|page=52|url=https://books.google.com/books?id=35cMAQAAMAAJ&q=Comptometer+1882|language=en}}</ref>
and started building the first prototype during the American [[Thanksgiving (United States)|Thanksgiving]] holidays of 1884. Because of his limited amount of money, he used a macaroni box for the outside box, and skewers, staples and rubber bands for the mechanism inside. It was finished soon after [[New Year's Day]], 1885. This prototype, called the macaroni box,<ref>(fr) Jean Marguin, ''Histoire des instruments et machines à calculer'', page 125, Hermann, 1994</ref> is in the [[Smithsonian Institution]] in [[Washington, D.C.]], United States.

Shortly after, Robert Tarrant, the owner of a [[Chicago]] workshop, gave Felt a salary of $6 a week, a bench to work on, and what would add up to $5,000 to build his first practical machine, which he finished in the autumn of 1886.

By September 1887, eight production machines had been built.

===Comptometer and comptograph===
[[Image:Mechanical-Calculator.png|thumb|left|<div align="center">Comptograph (1914)</div>]]

The original comptometer design was patented by the American Dorr E. Felt. The first two patents were granted on July 19, 1887<ref>[https://patents.google.com/patent/US366945 U.S. Patent No. 366,945], filed on July 6, 1886</ref> and on October 11, 1887.<ref>[https://patents.google.com/patent/US371496 U.S. Patent No. 371,496], filed on March 12, 1887</ref>

Two years later, on June 11, 1889, he was granted a patent for the Comptograph.<ref>[https://patents.google.com/patent/US405024 U.S. Patent No. 405,024], filed on January 19, 1888</ref>  A Comptograph is a comptometer with a printing mechanism making it more like a key-set calculating machine (even though the keys are registered as they are typed and not when a handle is pulled), therefore slower and more complicated to operate. It was the first printing-adding machine design to use individualized type impression which made its printed output very legible.

The first comptograph was sold to the Merchants & Manufacturers National Bank of Pittsburgh, PA. in December 1889. It was the first sale of a {{nowrap|recording-adding}} machine ever. This machine is now on display at the Smithsonian Institution in Washington, D.C..

The Felt & Tarrant Manufacturing Company built both comptometers and comptographs throughout the 1890s. In 1902, the Comptograph Company was set up to manufacture comptographs exclusively, but was shut down at the beginning of [[World War I]].

Forty years later, in the mid-1950s, the Comptometer Corporation reused the name Comptograph for a line of 10-key printing machines.

===Competition===
The comptometer was the first machine in production to challenge the supremacy of the [[arithmometer]] and its clones; but not immediately, it took almost three years to sell the first hundred machines.<ref>{{cite book|last=Felt|first=Dorr E.|title=Mechanical arithmetic, or The history of the counting machine|publisher=Washington Institute|location=Chicago|page=[https://archive.org/details/mechanicalarithm00feltrich/page/n7 4]|year=1916|url=https://archive.org/details/mechanicalarithm00feltrich}}</ref>
[[Image:DesktopMechanicalCalculators inProduction intheXIXCentury.svg|thumbnail|upright=2.7|center|<div align="center">Desktop Mechanical Calculators in production during the 19th century</div>]]