Gilson Binary Circular Slide Rule


This two-sided aluminum circular slide rule is coated with white celluloid enamel. The front has two interlocking yellow-green plastic arms, pivoted at the center with a metal nut and bolt with metal washers on both front and back. The back has one rotating arm. Thirteen circles of scales are on the front, including C (for multiplication, division, and proportion), CI (C inverted), A (squares), K (cubes), logarithms, a spiral log-log scale (marked from 1.0015 to 1,000,000), two binary scales for adding and subtracting fractions, a scale of drill sizes, a scale of thread sizes, and millimeters. The front is marked near the center: THE BINARY SLIDE RULE (/) MADE IN U.S.A. (/) COPYRIGHTED 1940.

Three concentric circles forming a scale of degrees, sines, and tangents are on the back. Inside this scale is a chart for decimal equivalents of fractions. The back is marked: COPYRIGHTED (/) 1931 (/) GILSON SLIDE RULE CO. (/) STUART, FLA. The sets of scales are almost the same as those on 1998.0119.01 and 1989.0032.01, which are both Gilson Midget circular slide rules, but the scale of thread sizes is in United States Form instead of United States Standard. Because it does not have alternating yellow and white stripes, this rule is unusual for a Gilson Binary slide rule. There is a case for this rule.

References: Sphere Research Corporation, "Gilson Binary/Atlas Circular Slide Rule Operating Information,"; Clippings Scrapbook, page 82, Cummings Library, Palm City, Fla.

Date Made: after 1940

Maker: Gilson Slide Rule Company

Location: Currently not on view

Place Made: United States: Florida, Stuart

Subject: Rule, CalculatingMathematics


See more items in: Medicine and Science: Mathematics, Science & Mathematics, Slide Rules


Exhibition Location:

Credit Line: Gift of Lewis H. Strauss

Data Source: National Museum of American History

Id Number: 1979.0816.01Catalog Number: 1979.0816.01Accession Number: 1979.0816

Object Name: calculating ruleslide rule

Physical Description: aluminum (overall material)celluloid (cursor material)metal (part material)Measurements: overall: 21.5 cm x 21.5 cm x 1.5 cm; 8 15/32 in x 8 15/32 in x 19/32 in


Record Id: nmah_1127889

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.