Account-o-Graph Calculating Machine

This lever-set, manual non-printing proportional rod calculating machine has a black steel frame and a steel base. Nine levers move forward to set numbers, with a row of windows in front of the levers showing the number set. Right of the levers is the operating crank.
In front is a carriage that moves when a release button is pushed. It has eight numeral wheels to record revolutions of the crank, and 16 numeral wheels to record results. These wheels are covered with glass. Numbers also may be set in the result register by rotating thumbscrews in the front of the carriage. This is done to set a dividend. Below the thumbscrews is a lever for zeroing the result register. There is a space for another zeroing bar or lever, but it has broken off.
To the left of the setting levers and what may be a second carriage release button are two levers. One may be set at N or C. When it is set at N, the number in the revolution register increases by one whenever the crank is rotated. When it is at C, one rotation leads to subtraction in the revolution register. The other lever may be set at ADD.MULT or SUBT.DIV., depending on the arithmetic operation desired.
A brass tag screwed to the top of the machine reads: THE-ACCOUNT-O-GRAPH (/) MONTREAL. It also reads: MODEL M. A mark on carriage on the left reads: MADE IN GERMANY. A mark on the middle of the back of the machine reads: 2438.
This machine closely resembles the Mercedes-Euklid Model 1. It is from the collection of L. Leland Locke.
Compare MA*330821.
An application for a design trademark for a calculating machine called The Account-o-Graph was filed in the United States September 2, 1913, and granted shortly thereafter. The application stated that the term had been used in commerce since May of that year hence the date of the object.
C. Hamann, "Calculating Machine," U.S. Patent 1,011,617, December 12, 1911. This patent was assigned to the Mercedes Bureau-Maschinen Gesellschaft of Berlin.
Official Gazette of the United States Patent Office, vol. 195, #2, October 14, 1913, p. 531.
Currently not on view
date made
ca 1913
place made
Deutschland: Berlin, Berlin
Physical Description
rubber (overall material)
glass (overall material)
metal (overall material)
overall: 18 cm x 38 cm x 28.1 cm; 7 3/32 in x 14 31/32 in x 11 1/16 in
ID Number
catalog number
accession number
Credit Line
Gift of L. Leland Locke
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Calculating Machines
Data Source
National Museum of American History, Kenneth E. Behring Center


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