Dietzgen 1732 Decimal Trig Log Log Duplex Slide Rule

This ten-inch, two-sided wooden slide rule is coated with white plastic and has a glass indicator with plastic and metal edges. The endpieces are L-shaped metal. The front of the base has L, LL1, DF, D, LL3, and LL2 scales, with CF, CIF, CI, and C scales on the slide. The top of the base is marked: DIETZGEN MANIPHASE MULTIPLEX DECIMAL TRIG TYPE LOG LOG RULE CAT. NO. 1732. The back of the base has LL0, LL00, A, D, DI, and K scales, with B, T, ST, and S scales on the slide. The top of the base is marked: EUGENE DIETZGEN CO. PATS. 2,170,144 2,285,722 MADE IN U.S.A. 530361. The case is cardboard covered with black leather. A Dietzgen logo is on the flap—the letter D inside the letter E inside the letters Co. Paper taped to the case is marked: PHILIP KRUPEN.

Model 1732 does not appear on a 1943 price list for the Eugene Dietzgen Co. of Chicago, but an instruction manual for this model was published in 1946. A drawing in this manual shows the same scales that are on this slide rule. Although the model is advertised in Dietzgen's 1953–1954 catalog, the log and K scales are arranged very differently from this rule. Hence, the rule apparently dates from 1944 to 1952.

Three U.S. Naval Academy professors applied for the patents mentioned on this slide rule in 1937 and 1938. These patents dealt with arranging and coloring scales so that problems could be solved in the fewest steps. They were also cited on Keuffel & Esser slide rules, models 4080 and 4081. (See 1992.0437.01, 2007.0181.01, 318482, 334387, 1990.0687.01, and 1986.0790.03.) The inventors also wrote instruction manuals for K&E, such as 1987.0085.02 and 2007.0181.01.01. The scales on the patents match those on this rule, except that the positions of the LL0 and LL00 scales are reversed.

This slide rule was given to the Smithsonian in 1986 by the physicist Philip Krupen (1915–2001). Krupen received his BS from Brooklyn College in 1935, worked on the development of the proximity fuze during and after World War II, earned a master's degree in physics from George Washington University, and spent a total of 38 years working for the U.S. government before his retirement in 1973. It seems possible that he acquired the rule while working on his master's degree.

References: Robert Otnes, "Dietzgen Patents, Runners, and Log Log Scales," Journal of the Oughtred Society 5, no. 2 (1996): 45–48; H. Loren Thompson and Ovid W. Eshbach, The Dietzgen Maniphase Multiplex Decimal Trig Type Log Log Slide Rule No. 1732 (Chicago: Eugene Dietzgen Co., 1946), http://sliderulemuseum.com/Manuals/M179_Dietzgen1732Manual1946.pdf; Dietzgen School Catalog (Chicago, 1953), 27; Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939), and "Slide Rule" (U.S. Patent 2,285,722 issued June 9, 1942).

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