Keuffel & Esser Instruction Manual for Polyphase Duplex Slide Rule

This 92-page salmon-colored paperback book was received with 1981.0933.03. Its citation information is: William E. Breckenridge, The Polyphase Duplex Slide Rule: A Self Teaching Manual (New York: Keuffel & Esser Co., 1924). Breckenridge earned an A.M. in mathematics from Columbia University in New York City, was chair of the mathematics department at Stuyvesant High School around 1909–1910, served as an associate editor of The Mathematics Teacher from 1913 to 1928, and apparently also taught at Columbia.

Breckenridge explains the basic features and operations of the slide rule, discusses the history and theory of slide rules, provides methods for solving "advanced problems," treats plane trigonometry, solves triangle problems, and provides "typical examples relating to various occupations," such as secretarial work, excavation, and retail. Finally, he shows how to set the slide rule to solve various mechanical formulas and lists tables of equivalents for the basic C and D scales. In chapter one, a previous reader, presumably the donor, William J. Ellenberger, has checked off the examples and filled in the answers to the problems. An advertisement for K&E's other specialty and general slide rules appears at the back of the book. This manual sold for 50 cents.

A digitized copy of The Polyphase Duplex Slide Rule is available at http://sliderulemuseum.com/Manuals/M205_KE_PolyphaseDuplexSlideRule_4088-3_1924.pdf.

Reference: Keuffel & Esser Co., Price List, Applying to General Catalogue, 36th ed. (New York, 1925), 44, 90.

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