For most of human history, doing arithmetic, while sometimes aided by devices like the abacus or adders, was fundamentally an act of human intelligence. In the 17th and 18th century, a few natural philosophers and clockmakers designed and built machines that could add. By the end of the 19th century, these sold as commercial products. Some small and easily portable versions of the instrument were within the price range of individuals. These often were operated with a stylus.
Other adding machines had a column of keys for each digit entered. Such so-called full keyboard machines were made and sold by several American manufacturers, most notably the Burroughs Adding Machine Company of Detroit and the Felt & Tarrant Manufacturing Company of Chicago. Burroughs machines also printed numbers entered and sums computed, easing the work of bank clerks and accountants. A third type of adding machine had only a few keys, usually ten. Built experimentally from the 1850s, ten-key adding machines dominated the market a century later. Finally, on a few adding machines operators entered numbers by turning wheels or moving levers with their fingers.
After the introduction of electronic components known as transistors in the 1950s, a few manufacturers began to sell desktop electronic calculators. In the 1970s, inexpensive electronic calculators, using microchips, displaced adding machines altogether. Calculating machines, which could multiply (and, sometimes, divide), met a similar fate.
The collections of the National Museum of American History include machines and models of machines from the corporate collections of both Felt & Tarrant and Burroughs. There are a few models sent by inventors to the U.S. Patent Office. The collection also has adding machines used by a wide range of businesses, government and religious institutions, and individuals.
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