Loga-Calculator Cylindrical Slide Rule

This large cylindrical slide rule consists of an aluminum frame supporting a horizontal rotating aluminum drum. Paper covering the drum is marked with 60 logarithmic C and D scales that are 20.5" long and run from 1,000 to 10,000. Each scale repeats part of the previous scale, so the instrument is approximately equivalent to a linear slide rule 50 feet (or 15m) long. A slotted cylindrical sleeve that is 13" long fits over the drum. It slides back and forth. The right end of the sleeve is secured in an aluminum ring. The ring and sleeve can rotate independently of each other.

The sleeve's 60 slats are marked with logarithmic scales that run from 100 to 1,000. Four small clear celluloid triangles attached to the slats serve as indicators. Black bands on either side of the drum and on the left side of the sleeve are marked with numbers from 1,000 to 9,623. The bands on the sleeve were originally covered with clear celluloid.

The side pieces of the frame are both marked: LOGA. The ends of the drum are both marked: LOGA-CALCULATOR • ZURICH. The band on the right side of the sleeve is marked: Loga - Calculator 15m Patente Daemen Schmid, Uster - Zürich.

The Swiss firm of Heinrich Daemen-Schmid manufactured approximately 30,000 cylindrical Loga-Calculators between 1900 and 1935. Daemen-Schmid patented the device in the United States in 1912. The donor, Jacques Kayalaff (1898–1983), was an international banker who used this instrument for calculations relating to currency exchange. He purchased it around 1925 for $500.

References: Accession File; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 42, 44; Heinrich Daemen-Schmid, "Computing Device" (U.S. Patent 1,036,575 issued August 27, 1912); Heinz Joss, "350 Jahre Rechenschieber, und was die Region Zürich dazu beigetragen hat (350 Years of Slide Rules, and What the Zurich Region Has Contributed)," Vierteljahreszeitschrift der Naturforschenden Gesellschaft in Zürich 146, no. 2–3 (2001): 75–82, http://www.rechenschieber.org/zurich.html.

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