Guedon Pocket Simplex Slide Rule

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This one-sided, five-inch steel linear slide rule is painted white. The scales are not lettered, but on the base they are equivalent to A and D scales and on the slide they are the equivalent of B, CI, and C scales. The bottom of the base is marked: GUEDON. CAMDEN. NEW JERSEY. It is also marked: PATENT PENDING and MADE IN U. S. A.
The base has grooves along the top and bottom of both the front and the back. The front grooves hold a celluloid indicator with concave curves on both sides. The back grooves hold a piece almost as wide as the base that serves as a support for the slide. The slide is a narrower metal piece, hooked to the support at both ends. The front of the support has a table for converting fractions to decimals; on the back are scales of 12.5 cm, divided to millimeters, and of 5 inches, divided to 32nds of an inch. The rule fits in a cardboard sleeve coated with brown synthetic leather.
According to a letter in the Keuffel & Esser collection at the MIT Museum, the Guedon company was making rules of this type in 1943 and selling them wholesale for 50 cents.
Reference: International Slide Rule Museum, "Miscellaneous USA,"
Currently not on view
date made
place made
United States: New Jersey, Camden
Physical Description
metal (overall material)
plastic (cursor material)
paper (case material)
overall: 5.7 cm x 16.3 cm x .4 cm; 2 1/4 in x 6 13/32 in x 5/32 in
ID Number
accession number
catalog number
Credit Line
Gift of David G. D. Hecht
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History


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