Smithsonian museums continue to be closed to support the effort to contain the spread of COVID-19. Read a message from our director, and check our website and social media for updates.

Keuffel & Esser 4071 Duplex Slide Rule

Keuffel & Esser 4071 Duplex Slide Rule

<< >>
Usage conditions apply
This ten-inch duplex mahogany slide rule is coated with white celluloid on the front and back; the edges are bare. Unlike earlier slide rules from the Keuffel & Esser Company, such as MA.318477, the end pieces are silver-colored metal (not brass) and the indented edges of the end pieces face in instead of out. The indicator is glass in a brass frame, which was called the "clam shell" style.
The scales are labeled. On both sides, the top of the base has an A scale and the bottom of the base has a D scale. The slide has B and C scales on one side and BI and CI scales on the other side. On one side, the bottom of the base is marked: KEUFFEL & ESSER Co.N.Y. It is also marked there: B.S.5470. On the other side, the bottom of the base is marked in red: PAT. OCT. 6. 1891. The bottom edge of the indicator is engraved: KEUFFEL & ESSER CO (/) NEW–YORK.
The instrument fits in a cardboard box covered with black morocco leather. The large part of the box is embossed: KEUFFEL & ESSER Co. (/) DUPLEX (/) SLIDE RULE. The U.S. National Bureau of Standards (now the National Institute of Standards and Technology) transferred this instrument to the Smithsonian in 1965 as excess property.
K&E sold this instrument as model 4071 from 1901 to 1917. By this time, K&E was manufacturing slide rules from start to finish at its factory in Hoboken, N.J. In 1913, the shape of the end pieces was changed to an "L," as with MA.318475. That instrument also has patent dates of 1900 and 1908 on it, suggesting that this slide rule dates from 1908 or earlier. The 1909 catalog describes the 1908 patent as "pending." Model 4071 initially sold for $8.00 and was reduced to $7.00 in 1906 and to $5.00 in 1909.
References: William Cox, "Engineer's Slide-Rule" (U.S. Patent 460,930 issued October 6, 1891); Clark McCoy, "Collection of Pages from K&E Catalogs for the Early 4071 Family of Slide Rules,"; Catalogue of Keuffel & Esser Co., 30th ed. (New York, 1900–1901), 296; Catalogue of Keuffel & Esser Co., 31st ed. (New York, 1903), 306; Catalogue of Keuffel & Esser Co., 32th ed. (New York, 1906), 325; Catalogue of Keuffel & Esser Co., 33rd ed. (New York, 1909), 312; Catalogue of Keuffel & Esser Co., 34th ed. (New York, 1913), 303.
Currently not on view
Object Name
slide rule
date made
Keuffel & Esser Co.
place made
United States: New York, New York City
Physical Description
mahogany (overall material)
metal (part material)
celluloid (laminate material)
cardboard (case material)
leather (case material)
overall: 1.5 cm x 31 cm x 3.6 cm; 19/32 in x 12 7/32 in x 1 13/32 in
ID Number
catalog number
accession number
Credit Line
Transfer from National Bureau of Standards
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
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.


This looks very much like a slide rule that I picked up in a garage sale in the 1970s. I used it all through high school, and in my physics class in 1978 my teacher challenged another student who had a new (and expensive) pocket calculator and myself to solve a series of equations. We were within a second of each other.

Add a comment about this object