Duo Comptometer
date: label: date made
content: 1922
name: label: maker
content: Felt & Tarrant Manufacturing Company
notes: label: Description
content: This full-keyboard non-printing adding machine has a black metal case with six columns of black and white, octagonal keys, colored according to the place value of the digits entered. Complementary digits are indicated on the keys. Keys representing even digits are flat, those for odd digits are indented. In back of the keyboard is a movable carriage that contains a counter register and a result register above it. Numbers in the counter register can have up to seven digits. Those in the result register 13 digits.
label: Description
content: To the left of the number keys are two white keys, one for the key drive and one for the crank drive. To the right of the number keys is a white key that, when pushed, releases the keys. On the right side of the machine is a crank that may be rotated to enter numbers into the register when the “crank drive” key is pushed down. The machine is designed to combine key-driven addition and crank-driven multiplication. It is the first model of a “Duo” Comptometer, and comes from the collection of models at Felt & Tarrant Manufacturing Company. There is no provision for subtraction.
label: Description
content: A patent for the invention was filed July 31, 1923 and granted just over nine years later on August 2, 1932. It is patent 1,869,872. A metal tag stored with the object is marked: 134.
label: Description
content: Reference: Felt & Tarrant, Accession Journal 1991.3107.06.
label: Location
content: Currently not on view
place: label: place made
content: United States: Illinois, Chicago
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Adding Machines
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content: Science & Mathematics
creditLine: label: Credit Line
content: Gift of Victor Comptometer Corporation
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.323651
label: catalog number
content: 323651
label: accession number
content: 250163
objectType: label: Object Name
content: adding machine
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: steel (overall material)
label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: 16.4 cm x 35.6 cm x 34.5 cm; 6 15/32 in x 14 1/32 in x 13 19/32 in