A 20″ polyphase duplex slide rule made of celluloid laminated on a mahogany surface. The cursor is made of glass with a metal frame and a single black marking line. Comes in a brown leather case. Scales: Front: K, A, B, S, T, C1, D, L. Back: DF, CF, CIF, C, D.
Accession Number: 2010.lej.13
Primary Materials: Celluloid, Mahogany, Glass, Steel
Old inventory number = 13.
Markings: “422652; <N4088-5>; PAT. June 5, 00 Dec 22 ï¿½08”.
Dimensions (cm): Height = 1.2, Width = 5.2, Length = 57
Function: For facilitating calculations.
Good: The glass cursor window is cracked. The cover of the leather case is damaged, leaving the case open on one end.
Manufacturer: Keuffel and Esser Co., New York
Date of Manufacture: c. 1935-1938
Additional Information and References: