This is a replica of the prototype for the Comptometer, a key-driven adding machine invented by Dorr E. Felt of Chicago. It is an open wooden box (originally used to store macaroni) with one row of "key stems" across the top. There are five skewers in the row, although there are holes for nine of them. Beneath this are five wooden levers and then five levers with rows of wooden discs on them. Further mechanism at the front of the machine incorporates both corks and metal gears and discs. Rubber bands, used to set the levers to accept the next keystroke, are missing.
Compare the original, which has catalog number MA.311192.
Reference:
J. A. V. Turck, Origin of Modern Calculating Machines, Chicago: Western Society of Engineers, 1921, pp. 52-56.
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