Hemmi Simplex Slide Rule Retailed by Post (1446)

Hemmi, a Japanese slide rule firm established in 1895, became notable after it began in 1912 to apply celluloid to bamboo, resulting in rules that did not shrink or expand like wooden rules. Hemmi also made rules for export, and it became the sole supplier of linear slide rules to the Frederick W. Post Company of Chicago by 1932. Post sold model 1446 between 1931 and 1949 for $1.50. The donor reported that he purchased this example in 1936 while studying at Colgate University. This date is consistent with the company logo on the case, which was in use in the 1930s, and with the lack of reference on the instrument to "Occupied Japan," as Hemmi rules were marked from 1946 to 1950. Hemmi products were not available in the United States during World War II.

This one-sided bamboo rule is coated with white celluloid only on the front. There are A and D scales on the base. The D scale is marked at each end: Quot (/) +1; Prod (/) -1. The slide has B and C scales on one side and S, L, and T scales on the other side. The indicator is glass in a metal frame. The rule's backing is clear and silver celluloid. It contains a chart with fractions converted to decimal numbers, powers of П, relationships between scales C and D, and weights of metals.

The center top of the base is marked in red: THE FREDERICK POST CO. NO. 1446. The center bottom of the base is marked in black: "SUN" (between two drawings of the sun); HEMMI; MADE IN JAPAN. The edge of the indicator is also engraved: SUN (between two drawings of the sun) HEMMI.

The rule is stored in a rectangular black Fabrikoid case which is opened by removing the right end. This end is marked in white: POSTS (/) 1446. The back of the case is marked: MADE IN JAPAN. The rule came with a stapled leaflet of instructions, 1982.0386.03.

References: Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 79–82; International Slide Rule Museum, "Slide Rule Dates and Time-Lines," http://sliderulemuseum.com/SR_Dates.htm; Posts Dependable Drawing Materials, 18th ed. (Chicago: The Frederick Post Company, 1936), 174. Price lists for this catalog dated August 1937 and May 1940 show model 1446 on pages 11–12 and 27–28, respectively.

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