Keuffel & Esser 4071-3 Polyphase Decitrig Duplex Slide Rule

This ten-inch mahogany duplex linear slide rule is almost completely coated with white celluloid. The frameless glass indicator has plastic edges. On one side, the base has K and A scales at the top and D and DI scales at the bottom. The slide has B, T, SRT, and S scales. Divisions of angles are indicated in decimal fractions. The left side of the slide is marked with the serial number 330508, with the number 508 printed on the left side of both parts of the base.

The other side of the rule has a DF scale on the top of the base and D and L scales on the bottom of the base. The slide has CF, CIF, CI, and C scales. The top of the base is marked in red: KEUFFEL & ESSER CO.; PATS. 2,500,460 2,168,056 2,170,144 PAT PEND.; MADE IN U.S.A. The right side of the slide is marked with the K&E logo, a copyright sign, and the model number, 4071-3. The instrument fits in an orange leather case with the K&E logo on the flap. Inside the flap is written in ink: H. R. L. (/) JULY '62.

Keuffel & Esser Company of New York sold this model from 1939 to 1967. The combination of scales on this example was sold beginning in 1955, and the model was renumbered in 1962 to 68-1502. Thus, the rule was probably manufactured between 1955 and 1962. The serial number is consistent with this dating.

The donor, Alfred E. Brown, was a research chemist for Celanese Corporation, which partnered with K&E in the 1960s to produce a special version of the 68-1555 slide rule (see 1993.0357.01). However, it is not known how this rule came into Brown's possession.

References: Clark McCoy, "Collection of Pages from K&E Catalogs for the 4071-3 Family of Slide Rules," http://www.mccoys-kecatalogs.com/KEModels/ke4071family.htm; Carl M. Bernegau, "Slide Rule" (U.S. Patent 2,168,056 issued August 1, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939); Herschel Hunt, "Slide Rule" (U.S. Patent 2,500,460 issued March 14, 1950); Walter Shawlee II, Ted Hume, and Paul Ross, "Keuffel & Esser Co. Slide Rules," Sphere Research Corporation, http://www.sphere.bc.ca/test/ke-sliderule.html; "Alfred E. Brown Chemist," The Washington Post, March 19, 2004, http://www.washingtonpost.com/wp-dyn/articles/A9676-2004Mar19_2.html.

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