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UNIS Marc Slide Rule made for The Dominion Bridge Company, Limi

L.E. Jones

A 5″ slide rule with a celluloid stock and slide of xylonite or ivorite. It is a Mannheim type of slide rule with scales only on the front side of the slide. The cursor consists of a brass frame and glass indicator with a single red line. Comes in a leather case. Scales: Front: A, B, C, D (names of scales not indicated). There are also centimeter and inch rulers. Markings: Bté S.G.D.G.-Marc-Paris (Made in France); [Engraved on the back] Dominion Bridge Company, Limited. Montreal, Ottawa, Toronto, Winnipeg, Calgary and Vancouver.

Accession Number: 2010.lej.38

Alternative Name:

Primary Materials: Plastic, Brass, Glass

Markings: Old Inventory Number = 38.

Dimensions (cm):

Length = 14 cm; Width = 3.3 cm; Height = .4 cm

Function: Facilitating calculations.


Item is in good condition. The plastic has warped and discolored making it difficult to move the slide. The brass slide frame is oxidizing.

Associated Instruments:

Manufacturer: UNIS Marc, Paris, France

Date of Manufacture: c. 1930s to 196


Additional Information and References:

Historical Notes: