Comptograph

This full-keyboard printing manual adding machine has a cherrywood case and eight columns of metal keys, with white discs set in the metal key tops. Digits and complements of digits are shown on the discs. Each column has nine keys, with a spring around each key stem. The cover under the keys consists of wooden slats with holes drilled in them. Each column of keys has one slat. These are alternately of cherry and a lighter-colored wood. A shaped tin plate at the front has nine windows cut in it to show nine metal wheels that record totals. Eight levers above the dials serve as decimal markers. On the right side toward the front are a knob and a small lever. Depressing the lever allows one to turn the knob and zero the total.

To the right of the keyboard is a large button that advances the paper tape and may print the total. This tape and the mechanisms for printing the numbers entered and the totals are behind the keyboard. Apparently printed totals can have up to eight digits. The paper tape is set inside a cherrywood lid that folds down when the machine is not in use. A knob on the right side at the back advances the carriage when loading paper. Different widths of paper tape can be used and the tape position adjusted.

This machine is shown in Turck, p. 118. According to that reference, it was purchased and used for ten years by the Merchants and Manufacturers Bank of Pittsburgh, Pa., and presented by Felt to the National Museum. In fact, this machine did not come to the Museum until long after Felt’s death. The same picture is in the Accession Journal of the Felt & Tarrant Collection, with object #19. There is no indication there where this object was used.

Compare to MA.322454.

References:

J. A. V. Turck, Origin of Modern Calculating Machines, Chicago: Western Society of Engineers, 1921, pp. 116-120.

Felt & Tarrant, Accession Journal, 1991.3107.06.

Currently not on view