Monroe Model K-121 Calculating Machine
date: label: date made
content: 1926
name: label: maker
content: Monroe Calculating Machine Company
notes: label: Description
content: This manual, full-keyboard non-printing modified stepped drum calculating machine has a metal frame painted black and a steel keyboard painted green. In the six columns of black and white color-coded keys, keys for odd digits are concave and those for even digits are relatively flat. At the bottom of each column is a red clearance key. Metal rods between the rows of keys serve as decimal markers.
label: Description
content: Three key stems are in a column to the right of the number keys. One clears the entire keyboard. The other two are set to determine whether or not the keyboard clears after each calculation. The keys for these key stems are missing. A metal lever is to the right of the keyboard and a metal knob to the left. The operating crank on the right side rotates clockwise for addition and counterclockwise for subtraction.
label: Description
content: The carriage in back of the keyboard has a row of 12 white numeral dials for recording results and a row of six numeral dials behind these in the revolution register. The revolution register has black digits for addition and red ones for subtraction. There is no carry in the revolution register. Two thin metal rods between the windows of these registers carry decimal markers. The carriage shift lever is at the front of the machine. To the right of the result register is a knob for lifting the carriage. A zeroing crank for dials on the carriage is on its right side. A bell rings when the result passes through zero (as in over-division). The machine has four rubber feet.
label: Description
content: A mark on the front reads: MONROE. A mark on the back reads: MONROE (/) Calculating Machine Company (/) New York, U.S.A.. Stamped on the edge of the carriage on the back left is the serial number: 77811.
label: Description
content: Reference:
label: Description
content: J. H. McCarthy, <I>The Business Machines and Equipment Digest</I>, 1928, pp. 9-29 to 9-33.
label: Location
content: Currently not on view
place: label: place made
content: United States: New Jersey, Orange
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Calculating Machines
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content: Science & Mathematics
creditLine: label: Credit Line
content: Gift of Walton G. Banks, Inc.
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1984.0682.04
label: catalog number
content: 1984.0682.04
label: maker number
content: 77811
label: accession number
content: 1984.0682
objectType: label: Object Name
content: calculating machine
physicalDescription: label: Physical Description
content: plastic (overall material)
label: Physical Description
content: wood (overall material)
label: Physical Description
content: aluminum (overall material)
label: Physical Description
content: steel (overall material)
label: Measurements
content: overall: 19.5 cm x 39 cm x 40 cm; 7 11/16 in x 15 11/32 in x 15 3/4 in