Keuffel & Esser 4098A Mannheim Simplex Slide Rule

This five-inch white Xylonite (celluloid) linear slide rule has A and D scales on the base, with B and C scales on one side of the slide and S and T scales on the other side of the slide. All scales are divided logarithmically. The slide is not reversible. The top of the base is marked: KEUFFEL & ESSER CO. N.Y.; MADE IN U.S.A. The right end of the slide is marked: < 4098A >. The indicator is frameless plastic with plastic edges and metal screws.
The back of the slide rule has a scale of 5 inches divided to sixteenths of an inch and a scale of 13 centimeters divided to millimeters. The left end of the back of the rule is marked with a serial number: 79883. The back is also marked in gold: RCA MANUFACTURING CO. INC. The RCA logo (letters inside a circle) is to the right of this mark. The rule fits in a leather sheath marked: K & E CO. There is also black tape marked with the previous owner's name: L. MARTON.
Keuffel & Esser of New York sold model 4098A from 1936 to 1952. With the case, it cost $2.05 in 1936, $3.50 in 1947, and $4.50 in 1952. Compare to MA*322761, 1987.0634.01, and MA*308201.
Ladislaus L. (Bill) Marton (1901–1979) was born in Hungary, received his Ph.D. from the University of Zurich, and worked in Belgium from 1929 to 1938, where he and his wife, Claire, built one of the first electron microscopes. In 1938, he came to the United States, taking positions at the RCA Research Laboratories in Camden, N.J., and at the University of Pennsylvania. He presumably acquired the slide rule during this period; its serial number is consistent with a manufacturing date in the early 1940s. In 1946, he joined the National Bureau of Standards. After he retired in 1970, he was an honorary research associate in the Smithsonian's Electricity collections and left the slide rule in his desk.
References: Clark McCoy, "4098A Pocket Slide Rule,"; Catalogue of Keuffel & Esser Co., 38th ed. (New York, 1936), 324, 330; K&E Slide Rules and Calculating Instruments Price List (New York, 1947), 1; K&E Price List Applying to the 41st Edition Catalog (New York, 1951), 35; accession file.
Currently not on view
date made
Keuffel & Esser Co.
place made
United States: New Jersey, Hoboken
Physical Description
plastic (overall material)
metal (part material)
leather (case material)
overall: .5 cm x 16 cm x 3.5 cm; 3/16 in x 6 5/16 in x 1 3/8 in
ID Number
accession number
catalog number
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center


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