Thomas Arithmometer

This stepped drum manual non-printing calculating machine has a brass and steel mechanism held in a wooden case. A stepped drum is under each of ten levers that are pushed back to enter digits. The brass plate that covers the drums and top of the machine has slits in it to allow these and other parts to move. The edges of the slits next to digit levers are numbered from 0 to 9 to indicate the digit entered. A lever to the left of these is either pushed back for addition and multiplication or forward for subtraction and division. Further to the left is a compartment that holds the key to the machine. The lid is missing. Right of the digit levers is a crank for operating the machine. It has an ivory handle, which bends down to the left when not in use so that the lid closes.

Behind the levers is a movable carriage with 11 windows for the revolution register and 20 windows for the result register. Rotating a black knob on the right of the carriage zeros the revolution register, and rotating a knob on the left of the carriage zeros the result register. Rotating thumbscrews on the carriage enter numbers in both the revolution and the result registers. Decimal markers would fit in holes between the windows of the registers, but the markers are missing. The case is painted black and the lid is shaped so that it fits in holes in the sides of the case that allow for motion of the zeroing mechanisms in the carriage.

A mark at the center reads: THOMAS (...) INVENTEUR S’adresser (/) 44, RUE DE CHATEAUDUN, 44 (/) PARIS (/) No 1994 (/) EXPOSITION, 16. RUE DE LA TOUR DES DAMES. A mark under this reads: Imported by Jas W. Queen & Co. (/) PHILADA. A mark on the left reads: ADDON ET MULTON (/) SOUSTON ET DIVISON. The top of the case reads: Arithmomètre.

This machine came to the Smithsonian as a transfer from another U.S. government agency on March 5, 1968. It probably was from the National Bureau of Standards.

Compare to MA.335215, a very similar machine with serial number 1068 that dates from about 1873.

No references to the Thomas arithmometer appear in James W. Queen & Co. catalogs for 1874, 1877, 1880, 1881, 1882, 1883, 1884, or 1887.

Currently not on view