Hemmi Simplex Pocket Slide Rule Retailed by Post (1441)

This small (five-inch) one-sided slide rule is bamboo covered with white celluloid, with a clear celluloid and metal backing. A magnifying glass indicator has a metal frame. There are A and D scales on the base. The slide has B, CI, and C scales on one side and S, L, and T scales on the other side. The upper edge of the base has a four-inch ruler divided to thirty-seconds of an inch.
The back of the base is marked: THE FREDERICK POST CO. NO. 1441 (/) SUN (between two drawings of the sun) HEMMI JAPAN CF. A brown leather case is stamped on the flap: POST. Inside the case is stamped: MADE IN JAPAN and handwritten: R. FREEZE.
The instrument was made by the Hemmi Slide Rule Company of Tokyo, Japan, and sold by the Frederick Post Company of Chicago, Ill. In the 1930s and 1940s, Post sold this model for $2.70. The code CF on the slide rule indicates that this example was manufactured by Hemmi in June 1952. The donor, Richard Freeze, purchased it in Philadelphia around 1956–57, when he was a student at Drexel Institute of Technology (later Drexel University). He used it during classes in physics, mathematics, and industrial engineering. Later, he used it while working at a specialty chemical firm doing industrial engineering projects.
Compare to 1995.0087.01.
References: Accession file; Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 183–187, 211; Posts Dependable Drawing Materials, 18th ed. (Chicago: The Frederick Post Company, 1936), 173. Price lists for this catalog, dated August 1937 and May 1940, show model 1441 on pages 11–12 and 27–28, respectively.
Currently not on view
Object Name
calculating rule
slide rule
date made
Frederick Post Co.
Physical Description
celluloid (laminate material)
bamboo (overall material)
leather (case material)
glass (cursor material)
overall: 2.2 cm x 12 cm x 1.9 cm; 7/8 in x 4 23/32 in x 3/4 in
in case: 3.3 cm x 13 cm x 2.1 cm; 1 5/16 in x 5 1/8 in x 13/16 in
place made
ID Number
accession number
catalog number
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center


"I have a little rule like this, #1441, but it says, "HEMMI MADE IN OCCUPIED JAPAN. " I thought that was rather interesting ?"

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