Hemmi Duplex Slide Rule Retailed by Post (Versalog 1460)

Description:

The Frederick Post Company, a 20th-century manufacturer and retailer of scientific instruments based in Chicago, did not make its own slide rules. From 1932, its exclusive supplier of linear slide rules was Hemmi, a Japanese firm. Hemmi was known for using a large-diameter variety of bamboo grown in Kagoshima Prefecture on the island of Kyushu. Company founder Jiro Hemmi (1878–1953) patented this innovation in several nations, including the United States in 1920.

While Post usually sold standard Hemmi models, around 1951 Hemmi created two ten-inch slide rules for Post, which sold in the United States as the model 1450 Versatrig and model 1460 Versalog. The Versalog was especially popular, selling several hundred thousand copies.

This example is bamboo, coated on all sides (except the ends) with white celluloid. The rule is held together with metal posts, one of which is engraved on the front: Wm. Krutz. The glass indicator has a metal frame with plastic sides. One side is marked: HEMMI JAPAN. The other side bears a Post logo in red, which has largely been rubbed away. The red Post logo and the serial number 015836 appear on the right front of the slide. The serial number indicates the rule was manufactured in 1959. This is confirmed by the date code JI on the bottom edge of the rule, which corresponds to a manufacturing date of September 1959.

The top edge of the rule is marked: CAT. NO. 1460; VERSALOG; FREDERICK POST CO.; HEMMI BAMBOO – JAPAN. The front of the base has LL0, LL/0, K, DF, D, R1, R2, AND L scales. The front of the slide bears CF, CIF, CI, and C scales. The LL/0, CIF, and CI scales are numbered in red. The back of the base has LL/1, LL/2, LL/3, D, LL3, LL2, AND LL1 scales. The back of the slide has T, Sec T and ST, Cos and S, and C scales. The LL/1, LL/2, LL/3, T, and Sec T scales are numbered in red. All the other scales are navy.

The rule fits into a black Fabrikoid case with a leather flap (stamped POST). The case could be hung from the user's belt, and it is labeled: W. K. KRUTZ. The case is stored in a red, white, and black cardboard box, along with a guarantee from Post and a ruler-sized white plastic set of conversion tables, copyrighted in 1950 by the Eugene Dietzgen Co., another prominent slide rule manufacturer. The rule also arrived with an instruction booklet, 1978.0800.02.

References: Jiro Hemmi, "Slide-Rule" (U.S. Patent 1,329,902 issued February 3, 1920); Walter Shawlee II, Ted Hume, and Paul Ross, "The Post Slide Rule Archive," Sphere Research Corporation, http://www.sphere.bc.ca/test/post.html; Bob Otnes, "Notes on Frederick Post Slide Rules," Journal of the Oughtred Society 7, no. 1 (1998): 7–10; Paul Ross and Ted Hume, "Slide Rules of the Frederick Post Company," Journal of the Oughtred Society 9, no. 2 (2000): 37–46; Ted Hume, "The Popular Post Versalog Slide Rule," Journal of the Oughtred Society 15, no. 1 (2006): 53–55; William Lise, "Japanese Slide Rules," 19 August 2004, accessed via Internet Archive Wayback Machine; E. I. Fiesenheiser, The Versalog Slide Rule: An Instruction Manual (Chicago: The Frederick Post Company, 1951).