A Comptometer is a type of mechanical (or electro-mechanical) adding machine. The comptometer was the first adding device to be driven solely by the action of pressing keys, which are arranged in an array of vertical and horizontal colums. An adding machine is a type of calculator. ...

Comptometer is, strictly speaking, a trade name of the Felt and Tarrant Manufacturing Company of Chicago (later the Comptometer Corporation), but was widely used as a generic name for the class of device. The original design was patented in 1887 by Dorr Eugene Felt, a US citizen. Chicago (officially named the City of Chicago) is the third largest city in the United States (after New York City and Los Angeles), with an official population of 2,896,016, as of the 2000 census. ... 1887 is a common year starting on Saturday (click on link for calendar). ... US,Us or us may stand for the United States of America us, the oblique case form of the English language pronoun we. ...

Although primarily designed for adding; division, multiplication and subtraction could also be performed. Special comptometers with varying key arrays (with from 30 to well over 100 keys) were produced for a variety of purposes, including calculating currencies, time and Imperial measures of weight. 8:17 am, August 6, 1945, Japanese time. ... Weight is the force exerted upon an object by virtue of its position in a gravitational field. ...

In the hands of a skilled operator, comptometers can add numbers very rapidly, since all the digits of a number could be entered simultaneously using as many fingers as is required, making them much faster than using an electronic calculator. Consequently, in specialist applications they remained in use in limited numbers into the 1990s, but with the exception of a handful of machines, have now all been superseded by the use of computer software. A basic arithmetic calculator. ... Events and trends The 1990s are generally classified as having moved slightly away from the more conservative 1980s, but keeping the same mind-set. ... Computer software (or simply software) refers to one or more computer programs held in the storage of a computer for some purpose. ...

See also

• Genericized trademark

A genericized trademark (Commonwealth English genericised trade mark), sometimes known as a generic trade mark, generic descriptor or proprietary eponym, is a trademark or brand name which has become synonymous with the general or formal term for a particular type of product or service, to the extent that it often...

External link

• Comptometers