Gerber GraphAnalogue, Model GA-103

This instrument has a rectangular aluminum base, painted black, with unpainted aluminum endpieces. A clear plastic piece with a crosshair, attached to an aluminum bracket, slides over the base. The base is marked with 15 scales, labeled RI, RF, RC, I, F, CM, T, S/CO, D, ( )2, ( )1/2, ( )1/3, L10, Le, P. It is also marked: THE GERBER SCIENTIFIC INSTRUMENT COMPANY HARTFORD, CONN. GERBER GRAPHANALOGUE MODEL GA-103 PATS. 2530955–2561020 OTHERS PENDING MADE IN U.S.A.
Across the top are two metal springs, encased in plastic and attached to the left endpiece and the slide. The front spring has six small, equally spaced discs that are marked with the numbers 0, 2, 4, 6, 8, and 10. The back spring has 103 coils, 100 of which are calibrated. Every tenth coil is marked red, every fifth is blue-green, and the others are white. The bottom of the instrument is marked: R-203.
A tan leather case is lined with brown velvet. Inside the lid is marked: THE GERBER SCIENTIFIC INSTRUMENT COMPANY (/) HARTFORD, CONNECTICUT. Two orange cards have grids and are marked: SPRING LENGTH = 1.000 INCHES. One card has a curve drawn in pencil and is marked in ink: CALIBRATION CURVE FOR (/) READING NON-LINEAR AMPLITUDES (/) DIRECTLY, MULTIPLIED BY SCALE (/) FACTOR. For an instruction manual, see 1994.0113.05.
Heinz Joseph Gerber (1924–1996) was a refugee from Nazi-controlled Austria. With a partner, he established the Gerber Scientific Instrument Company in Hartford, Conn., to manufacture the Gerber Variable Scale that he invented in 1945. (See 1994.0113.01 and 1994.3104.01.) By 1953 he developed a variation on that instrument that the company marketed as the GraphAnalogue, for converting graphs to linear, reciprocal, trigonometric, logarithmic, or probability equations. Gerber ultimately held about 650 U.S. and foreign patents for calculating instruments, digital drafting machines, and robotic and electronic manufacturing systems for products from electronics to textiles. The firm was renamed Gerber Scientific, Inc., in 1978.
References: Arthur Bartlett, "A Quick Spring to Success," Nation's Business (October 1949): 43–45, 62–64; Heinz Joseph Gerber, "Instrument for Measuring, Interpolating, and the Like" (U.S. Patent 2,530,955 issued November 21, 1950) and "Instrument for Measuring, Interpolating, and the Like" (U.S. Patent 2,561,020 issued July 17, 1951); "Our Founder," Gerber Scientific,; "Gerber Scientific, Inc. History," in International Directory of Company Histories, vol. 12 (St. James Press, 1996),
Currently not on view
Object Name
scale rule
scale in case
date made
ca 1953
Gerber Scientific Instrument Company
Physical Description
aluminum (overall material)
plastic (overall material)
paper (overall material)
leather (overall material)
cloth (overall material)
overall: 3.3 cm x 39.3 cm x 16.7 cm; 1 5/16 in x 15 15/32 in x 6 9/16 in
place made
United States: Connecticut, Hartford
ID Number
accession number
catalog number
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Scale Rules
Data Source
National Museum of American History, Kenneth E. Behring Center


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