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Decitrig Duplex Slide Rule

L.E. Jones

A 10″ slide rule made of celluloid on mahogany with a grooved frame and a metal-framed glass cursor. The stops are made of stainless steel. Comes in a black cardboard box. Scales: Front: L, LL1, DF, CF, CIF, CI, C, D, LL3, LL2 Back: LL0, LL00, A, B, T, STS, D, DI, K.

Accession Number: 2010.lej.10

Alternative Name:

Primary Materials: Mahogany, Glass, Stainless Steel


The left end of one side of the rule is engraved with the serial number “620637”. The top of the other side is engraved with “KEUFEL & ESSER CO.N.Y.; PATS, 1,488,686 1,930,852 PAT PEND; Made in U.S.A.” The right end of this side has the model number “<4081-3>”. One end of the case is marked “K&E DECITRIG DUPLEX / Trade Mark / Slide Rule / 4081-3.” The inside of the opening flap of the cardboard box has “L. E. Jones, 82 Moore Ave. Toronto [illegible]” written on it.

Dimensions (cm):

Length = 31.7cm, Width = 5.2 cm, Height = .7 cm

Function: Facilitating calculations.


Item is in very good condition. The cardboard container has been repaired with tape. The lid is partly detached.

Associated Instruments:

Manufacturer: Keuffel and Esser Co., New York, USA

Date of Manufacture: c. 1937-1939


Part of the L. E. Jones slide rule collection.

Additional Information and References:

Historical Notes:


  • Donated to UTSIC