Pickett N901-ES Simplex Slide Rule

This aluminum slide rule is coated in "Eye Saver" yellow, as denoted by the model number. It is held together with aluminum braces; the indicator is nylon (also denoted by the model number) with three metal screws. The front of the rule has A, D, and L scales, with B, CI, and C scales on the slide. The scales are about ten inches long. The slide and the top of the rule are both marked: MODEL N901-ES (/) SIMPLEX (/) MATH RULE. The other end of the slide bears the Pickett logo and the mark: MADE IN U.S.A.
The back of the rule has X and D* scales, with Y and C* scales on the slide. The top of the rule is marked: PICKETT, INC.; MODEL N901-ES; SIMPLEX MATH RULE. The bottom of the rule is marked: COPYRIGHT 1965; PICKETT, INC. SANTA BARBARA. CALIF.; MADE IN U.S.A.
The rule fits in a black leather sheath. The sheath was received in a green, white, and black cardboard box. One end of the box is marked: PickETT (/) 901-ES (/) ELEMENTARY MATH. It also is marked: about this rule: (/) 10 scales are keyed to (/) new math. Aids under- (/) standing of addition, (/) subtraction, multiplica- (/) tion, division and Base 10 (/) relationships. Grade 3 up. The inside of the box top flips up for display. The box slides into a green, white, and black cardboard cover. The top and sides of the box cover are each marked: PickETT; ALL METAL (/) SLIDE (/) RULE.
The box also contains a yellow paper slide rule guarantee and registration card. The object's serial number is A1216143. A 48-page instruction manual by Maurice L. Hartung is stored separately (1995.0126.02.01).
The X and Y scales were used for addition and subtraction and were unique to Pickett. Donor Lawrence J. Kamm conjectured that Hartung, a mathematics professor at the University of Chicago, recommended they be added to this product. According to Kamm, Hartung encouraged company cofounder Ross Pickett to market its slide rules only to schoolchildren. In order to provide scientists and engineers with access to rules such as the Decimal Keeper (1995.0126.01), Kamm opened a mail-order business that distributed Pickett's products.
References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: The Astragal Press, 1999), 209–210; Maurice L. Hartung, Complete, Semi-Programmed Teaching Instructions for the Use of Elementary Simplex Math Slide Rule (Santa Barbara, Calif.: Pickett, Inc., 1965); accession file; International Slide Rule Museum, "Pickett," http://sliderulemuseum.com/Pickett.htm.
Currently not on view
date made
after 1965
date received
Pickett & Eckel, Incorporated
place made
United States: California, Santa Barbara
Physical Description
aluminum (overall material)
plastic (cursor material)
leather (case material)
paper (case material)
overall: 3.6 cm x 33.8 cm x 9 cm; 1 13/32 in x 13 5/16 in x 3 17/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Lawrence J. Kamm
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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