TIM Unitas Calculating Machine

By the early 20th century, Germans who had gained experience in the calculating machine industry were opening new companies of their own. In 1907 Ludwig Spitz, an attorney who had represented German calculating machine firms, founded Ludwig Spitz & Co. in Berlin. The company sold improved forms of the arithmometer, particularly using designs of the engineer Robert Rein. These machine sold as the “T.I.M.,” which the company said stood for “Time is Money.” A German firm's choice of an English motto associated with Benjamin Franklin is noteworthy. Spitz was particularly proud of the “Unitas” machine, which united two carriages in one, making it possible to compute both subtotals and grand totals.
This relatively early example of the Unitas, made of brass and German silver, fits in a polished wooden case. It has eight levers for setting numbers, with windows behind the levers to show the number set up. Below these are the stepped drums, which are not complete cylinders, but only partial and hollow. They appear to be die–cast from a composite metal.
Behind these is a carriage with a seven-digit revolution counting register and a 12-digit result register. Behind this is a second carriage with a second result register. Metal rods carry sliding decimal markers for each register. The two carriages are held together on the left by a mechanism that can detach the back carriage from the front one.
Left of the digit levers is a lever for setting the machine to addition/multiplication or subtraction/division. When the lever and an adjacent smaller lever are both in the add position, both carriages show results of addition. When the lever is in the upper position and the adjacent lever is in the middle position, the first carriage shows addition and the back one subtraction. A crank for operating machine is at the right front. To the left is a small glass bottle for ink, held in its own compartment.
In the lid of the case of the machine is a table for converting shillings and pence to decimal fractions of an English pound and another table of decimal equivalents. The case can be locked but the key is missing. The bottom of the machine is hinged at the front and may be lifted to sit on metal legs at the back.
A mark on the left front of the machine reads: Ludwig Spitz & Co. (/) TIM (/) TIME IS MONEY (/) TRADE MARK. A mark in front of the setting levers reads: Rechenmaschinenfabrik LUDWIG SPITZ & Co., G. m. b. H., Berlin. A mark stamped on the right edge of the case reads: 0853. A mark stamped on the back edge of the case reads: 367. A mark on the front edge of the front carriage reads: 0724. A mark on the front edge of the back carriage reads: 0557.
This machine comes from the collection of Felt & Tarrant Manufacturing Company of Chicago.
From 1909 the Unitas was produced with a metal stand rather than the wooden case.
E. Martin, The Calculating Machines (die Rechenmaschinen), trans. P. A. Kidwell and M. R. Williams, Cambridge: MIT Press, 1992, pp. 194–196.
The Unitas, New York: Oscar Muller & Co., 1908.
Currently not on view
Object Name
calculating machine
date made
Ludwig Spitz & Co.
Physical Description
metal (overall material)
brass (overall material)
paper (overall material)
glass (overall material)
plastic (overall material)
overall: 14 cm x 44.8 cm x 25.5 cm; 5 1/2 in x 17 5/8 in x 10 1/32 in
place made
Deutschland: Berlin, Berlin
ID Number
catalog number
accession number
Science & Mathematics
Calculating Machines
See more items in
Medicine and Science: Mathematics
Calculating Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Victor Comptometer Corporation
Additional Media

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