Stephenson Adding Machine

This U.S. Patent Office model for a stylus-operated non-printing adding machine has a rectangular wooden base. Four adjacent rotating wheels are inset in the base, with a metal cover that fits over them. The three small wheels on the right each have a metal arm pivoted at their centers and ten evenly spaced indentations around the edge. The digits from 0 to 9 are marked on the cover just outside each of these wheels. The numbers increase counterclockwise going around the first and third wheels and clockwise going around the second wheel. The two middle wheels also have ten pins arranged just inside the indentations. The pins of one wheel are linked to the arm of the wheel to the right of it. The fourth, leftmost, wheel is larger and has 20 indentations and 20 pins. The indentations are numbered from 0 to 19 going counterclockwise. A two-wheeled device was manufactured under this patent.

A paper tag attached to the machine reads: No.137,107 (/) A.M. Stephenson (/) Adding Machines (/) Patented March 25th 1873. A second paper tag attached to the machine reads: A.M. Stephenson (/) Adding Machine (/) Received March 5th, 1872.

This instrument was in the collections of the Museums of the Peaceful Arts in New York City before coming to the Smithsonian Institution as a gift of L. Leland Locke.

Archibald M. Stephenson (1844-1913), the inventor of this instrument, was born in Indiana and spent most of his adult life in Illinois. He manufactured a version of this instrument in Joliet.

References:

U.S. Patent 137107, March 25, 1873.

R. Otnes, “A.M. Stephenson and His Adder,” Journal of the Oughtred Society, vol. 13 #2 (Fall 2004): pp. 55-60.

W. W. Stevens, Past and Present of Will County, Illinois, Chicago: S. J. Clarke Publishing Co., 1907, pp. 348-349.

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