Keuffel & Esser 4055 Favorite Simplex Slide Rule

This ten-inch mahogany linear slide rule is coated with white celluloid on the front and both sides of the slide. The base has A and D scales. The slide has B and C scales on one side and S, L, and T scales on the other. A paper table of equivalents and slide rule settings, based on U. S. Bureau of Standards Circular No. 47, is pasted to the back of the rule. See also 2001.0117.01. According to Eric Marcotte, this circular was in force from 1914 to 1936. Keuffel & Esser included it on slide rules from the 1920s to the 1950s.

The indicator is glass with a plastic frame, of the style used by Keuffel & Esser between 1915 and 1937, based on the patent indicated by the mark on the top edge of the frame: K&E.CO.N.Y. (/) PAT.8.17.15. The top of the base is marked in red: PAT. JUNE 5, 1900; KEUFFEL & ESSER CO. N.Y.; MADE IN U.S.A. For more on this patent, see MA.322761. Four expressions have been scratched into the front of the slide: x = A + B; ÷ = A – B; x – 1; ÷ + 1. The model number is printed at the right end in red: < 4055 >. The left end of the back of the slide and the front left corner of the base are marked with a serial number: 190673.

The rule is in a cardboard case covered with black morocco leather and heavily taped. It is marked: KEUFFEL & ESSER (/) FAVORITE (/) SLIDE RULE (/) 4055. It is also marked on the tape near one end: E. HELLER (/) ΣΦΕ. On the other side of that end, it is marked on the tape: PROPERTY OF (/) PETER (/) HELLER. K&E sold model 4055 from 1927 to 1943; the serial number suggests a date closer to 1927, when the instrument sold for $4.00. One owner of this slide rule was the mechanical engineer Edward Lincoln Heller (1912–2007), who received a BSfrom Lehigh University in 1934 and an MBA from Harvard University in 1939. It seems likely that he used the slide rule as a college student.

References: Willie L. E. Keuffel, "Slide-Rule" (U.S. Patent 651,142 issued June 5, 1900); Willie L. E. Keuffel, "Slide-Rule Runner" (U.S. Patent 1,150,771 issued August 17, 1915); Eric Marcotte, "The Evolution of a Slide Rule – The K&E 4053-3," http://www.sliderule.ca/4053.htm; Clark McCoy, "Collection of Pages from K&E Catalogs for the 4055 Family," http://www.mccoys-kecatalogs.com/KEModels/ke4055family.htm; Ed Chamberlain, "Estimating K&E Slide Rule Dates," 27 December 2000, http://www.sphere.bc.ca/test/ke/320-k+e_date2.jpg; "Heller, Edward L.," American Men and Women of Science, 12th ed. (New York: J. Cattell Press, 1972), 2620.

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