Keuffel & Esser 4211 Polar Planimeter

This German-made polar planimeter has a metal tracer arm attached to a brass arm painted black and holding a brass weight. The weight is marked: KEUFFEL & ESSER Co NY (/) GERMANY. A black frame, or carriage, on the tracer arm holds a white plastic measuring wheel with vernier and a horizontal white plastic registering dial. The carriage is marked in white: No 1380. A metal test plate is marked: 30[square]" 20[square]" 10[square]" 1.5[square]".

A wooden case covered with black leather is lined with blue velvet. The bottom of the case has a typewritten label: C. B. Schmeltzer (Personal). It is also marked: GERMANY. A rectangular paper label inside the lid of the case is marked: KEUFFEL & ESSER COMPANY (/) PLANIMETER NO 4211 (/) SERIAL NO 1380. The label has a table for different scales and values of units on the vernier. The constant is 16,000 square inches. The circumference of the measuring roller is handwritten as 2.38464 inches. Various values are written in pencil on the top of the label.

Keuffel & Esser began to advertise model 4211 in 1925 as a slimmer version of a planimeter sold as model 1111 from 1892 to 1901 and as model 4212 from 1901 to 1941. K&E stopped offering model 4211 between 1936 and 1939. It cost $25.00 in 1936. According to instructions received with the instrument (MA.317925.03), model 4211 was the simplest polar planimeter sold by K&E. Compare to MA.320138.

Chauncey Brockway Schmeltzer (1894–1974) owned this planimeter. He earned bachelor's and master's degrees in civil engineering from the University of Illinois in 1919 and 1920, where he taught until 1926. He also worked in private practice in Urbana, Ill., from 1921 to 1933; the serial number suggests he purchased the instrument around the middle of this time period. He then became an associate engineer appraiser for the Federal Land Bank of St. Louis until 1936. From 1936, he held the same title at the USDA's Bureau of Agricultural Engineering.

This instrument was received at the Smithsonian in 1975.

References: Clark McCoy, "Collection of Pages from K&E Catalogs for the 4210 Family of Polar Planimeters," http://www.mccoys-kecatalogs.com/PlanimeterModels/ke4210family.htm; Catalogue of Keuffel & Esser, 38th ed. (New York, 1936), 335; Winfield Scott Downs, ed., Who's Who in Engineering, 4th ed. (New York: Lewis Historical Publishing Company, 1937), 1217.

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