Keuffel & Esser 1634 Triangular Chain Scale

This 12-inch triangular boxwood rule has indentations along each side. One side has scales divided to 1/20" (numbered by ones from 0 to 24) and 1/50" (numbered by twos from 0 to 60). This side is marked: 1634 KEUFFEL & ESSER Co. N.Y. The second side has scales divided to 1/40" (numbered by twos from 0 to 48) and 1/80" (numbered by fours from 0 to 96). The third side has scales divided to 1/30" (numbered by twos from 0 to 36) and 1/60" (numbered by fours from 0 to 72). One end of the rule is marked: LARSEN.

The Eugene Dietzgen Company sold model 1626 from at least 1904, when it cost 90¢, to at least 1952, when it cost $2.30. William J. Ellenberger (1908–2008), who donated this object, studied electrical and mechanical engineering at The George Washington University between 1925 and 1934. He then worked for the Potomac Electric Power Company and the National Bureau of Standards. During World War II, he served in the U.S. Army Signal Corps. He was a civilian construction management engineer for the army from 1954 to 1968, when he became a private consultant.

References: Catalogue & Price List of Eugene Dietzgen Co., 7th ed. (Chicago, 1904), 160; Catalogue & Price List of Eugene Dietzgen Co., 12th ed. (Chicago, 1926), 168; Catalogue & Price List of Eugene Dietzgen Co., 14th ed. (Chicago, 1931), 189; Catalogue & Price List of Eugene Dietzgen Co., 16th ed. (Chicago, 1952), 215; "The GW Engineering Hall of Fame 2006 Inductees," http://www.weas.gwu.edu/ifaf/hall_of_fame_inductees_2006.php.

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