Skip to main content
Monroe adding calculator
Monroe adding calculator

Monroe adding calculator

Object number1996.051.0001
Date1922 - 1939
ClassificationsArtifacts
ObjectCalculator
Credit LineThom Dublin Collection/The Sixth Floor Museum at Dealey Plaza
MediumMetal
Dimensions6 1/2 x 13 1/2 x 9 1/2 in. (16.5 x 34.3 x 24.1 cm)
DescriptionMonroe Calculating Machine Company full keyboard rotary adding calculator from the Texas School Book Depository building. The machine is black metal with a dark green face with off-white, black and red buttons. There is a carriage at the top that moves from left to right and has two registers, one longer than the other. There are crank handles at the right side and on the front. The "Monroe" logo in block letters is painted on the front right of the machine and again on the back with "High Speed Adding Calculator" below. A gold-toned label on the underside of the machine reads: "Monroe, Calculating Machine Company, New York, U.S.A., No. 1, 100-135 volts 0-60 cycles A.C., 100-135 Volts D.C." The number "222550 S.H." is written on the bottom in white paint.
Curatorial Commentary
When he donated this item, Mr. Dublin told me he found the calculator in a large pile of discarded equipment outside the former Texas School Book Depository years after the assassination and thought it looked interesting.  Monroe was one of the largest office equipment manufacturers in the 1930s, so it is possible the machine was purchased new when D. Harold Byrd purchased the building in the mid-30s.  Whether the calculator was in use in 1963 is unknown.  It may have been discarded after the Texas School Book Depository company moved out in 1970. - Gary Mack, Curator