Thomas Arithmometer

This stepped drum manual non-printing calculating machine has a brass and steel mechanism that fits neatly in a wooden case. Ten levers are pushed back to enter digits, with a stepped drum below each lever. 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. Another lever, located 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 glass-covered compartment that holds the decimal markers, key, and loose parts to the machine. The operating crank is right of the digit levers. It's ivory handle folds down 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. The black knob for zeroing the revolution register is on the right of the carriage, and a knob for zeroing the result register is on the left. Both the revolution and the result register have thumbscrews for entering numbers and holes for decimal markers between the windows of the registers. The eighteen decimal markers in the compartment have a brass base and ivory top. 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 of the machine reads: THOMAS de COLMAR (/) A PARIS (/) INVENTEUR (/) No. 1068. A mark next to the lever near the center reads: ADDON ET MULTON (/) SOUSTON ET DIVISON. The lid of the machine is marked: Arithmomètre.

Thomas Egleston of Columbia University’s School of Mines was a judge in Group 1 (Mining, Quarrying and Metallurgy) at the 1873 exposition held Vienna. The firm of Thomas exhibited at this exposition, and it is possible that Egleston arranged to purchase this machine at that time.

An instruction book received with the instrument and stored separately is dated 1868.

Compare MA.328869.

References:

P. A. Kidwell, “Scientists and Calculating Machines,” Annals of the History of Computing, 12, 1990, pp. 31–40.

Robert H. Thustron, Reports of the Commisioners of the United States to the International Exhibition Held at Vienna, 1873, Washington: GPO, 1876, vol. 1, p. 118.

Currently not on view