Keuffel & Esser Linear Planimeter Invented by Frank R. Williams

This German silver instrument consists of three pieces. The first is a seven-inch tracer arm with a tracer point at one end and a measuring wheel with vernier and a peg at the other end. The peg fits into a groove on the second piece, which is a rectangular plate with a removable sliding ruler that is divided on all four sides into 96, 120, 150, and 180 parts. A pivoting rectangular blade is at the right end of the second piece. This piece is marked: KEUFFEL & ESSER Co N.Y. Pat. Dec. 8. 1903 No 7. The third piece is a folding L-shaped ruler. The long arm is graduated to 1/4-inch and numbered from 1 to 5. The short arm is divided to tenths of an inch and numbered from 5 to 20.
A rectangular hardwood case has green velvet lining the supports for the instrument. A small ivory plate screwed inside the lid is marked: KEUFFEL & ESSER CO. (/) NEW YORK (/) ST. LOUIS CHICAGO (/) SAN FRANCISCO.
Frederick (Frank) R. Williams of Syracuse, N.Y., patented this planimeter. He may have been a merchant who sold his grocery store in 1906. The instrument was never advertised in Keuffel & Esser catalogs. Since this example was donated by K&E in 1971 and since the serial number is so low (7), perhaps K&E manufactured it as a prototype or for use with its own steam engine indicators, but decided not to offer it for sale to the public. Compare to the linear planimeter invented by John Coffin, MA*323708, 1987.0107.03, MA*323705, and MA*323706.
References: Frank R. Williams, "Planimeter" (U.S. Patent 746,427 issued December 8, 1903); "Skaneateles," Syracuse Journal (January 10, 1906), 6,; Clark McCoy, ed., "Planimeters and Integrators in K&E Catalogs by Model Number,"; Bob Otnes, "American Planimeters," Journal of the Oughtred Society 11, no. 2 (2002): 59–64; accession file.
Currently not on view
Object Name
date made
Keuffel & Esser Co.
Physical Description
german silver (overall material)
wood (overall material)
fabric (overall material)
case: 4.3 cm x 19.7 cm x 8.5 cm; 1 11/16 in x 7 3/4 in x 3 11/32 in
place made
United States: New Jersey, Hoboken
ID Number
catalog number
accession number
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center


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