Patenta Multiplication Table

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This simple German table was intended as an aid to multiplication and division. Each side of the blue and white paper disc has a blue and white paper arm pivoted from the center. The disc has a diameter of 15 cm.; with the arm, the width is 15.6 cm.
Going in from the circumference, each arm has printed on it the numbers from 1 to 20 in a column. On each side of the disc there are 19 radial columns. On one side these are numbered from 2 to 20; on the other from 21 to 39. The “2” column contains multiples of 2, the “3” column multiples of 3, etc. To find, say, the product of 35 and 19, one lines up the arm next to the 35 column on the disc. Next to 19 on the arm is 665 (the desired product) on the disc.
The instrument is marked on both sides: PATENTA. It is also marked on both sides: D.R.G.M. (/) 145,796. The initials D.R.G.M. stand for Deutsches Reichgebrauchmuster, a temporary form of German intellectual property protection (not a full patent). D.R.G.M. numbers were first issued in 1891 and continued to be used through World War II. This number was issued in about 1901. A second form of the instrument, with more numbers, was issued later.
The object is described briefly in a column in the Zeitschrift für Mathematischen und Naturwissenschaftlichen Unterricht in 1903. This example was found in the collections of the National Museum of American History’s Division of Transportation around 1980.
“Besprechung von Lehrmitteln, Mathematik” Zeitschrift für Mathematischen und Naturwissenschaftlichen Unterricht34, 1903, p. 67.
D. von Jezierski, trans. R. Shepherd, Slide Rules: A Journey through Three centuries, Mendham, N.J.: Astragal Press, 2000, p. 102. This reference indicates that D.R.G.M. registered design 148526 was issued in 1901 and 173095 in 1902.
Currently not on view
date made
ca 1901
place made
Physical Description
paper (overall material)
overall: .2 cm x 15.6 cm x 15.6 cm; 3/32 in x 6 5/32 in x 6 5/32 in
ID Number
catalog number
accession number
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Mathematical Charts and Tables
Data Source
National Museum of American History


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