Keuffel and Esser Deci-Lon Slide Rule

Keuffel and Esser Deci-Lon Slide Rule

<< >>
Usage conditions apply
This Keuffel and Esser Deci-Lon slide rule is a model 68 1100 with 10-inch scales. The rule is made of a shatterproof synthetic material while the indicator is made of clear plastic with metal edges. Markings are in red and black. The front face is printed with 13 scales: Sq1, Sq2, DF, CF, CIF, L, CI, C, D, Ln0, Ln1, Ln2, Ln3. The reverse face is also printed with 13 scales: Ln-3, Ln-2, Ln-1, Ln-0, A, B, T, SRT, S, C, D, DI, and K scales. Printed on the reverse face and located on the right side of the lower rail is the serial number 178687 and located on the left-side of the center rail, made in U.S.A. When not in use, it is stored in an orange, stitched leather case with belt carrier. An imprint of the donor’s last name can be detected on the front of the case under the model name.
The donor purchased this slide rule from the Cornell University bookstore in September 1969. He used it in his coursework for physics engineering as well as nuclear engineering. After earning a master’s degree in nuclear engineering, he served for 42 years in the U.S. Navy.
Accession file.
Currently not on view
Object Name
slide rule
date made
ca 1969
Keuffel & Esser Co.
place made
United States
Physical Description
leather (overall, case material)
metal (overall, rule material)
plastic (overall, rule material)
overall, rule: 1.1 cm x 32.5 cm x 6.3 cm; 7/16 in x 12 25/32 in x 2 15/32 in
overall, case: 43.6 cm x 34 cm x 8.2 cm; 17 5/32 in x 13 3/8 in x 3 7/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Thomas Conran
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object