An Otis King Patent Cylindrical Slide Rule No 414 with Leather Case

An Otis King patent telescopic cylindrical slide rule, Model No 414, manufactured by Carbic Limited of London. The instrument is constructed from metal with a black lacquered cursor sleeve and silver-toned internal cylinders. It features two helical logarithmic scales printed on a yellowed substrate. The lower scale is marked SCALE No 414, CARBIC LIMITED, 51, HOLBORN VIADUCT, LONDON, E.C.1. PATENTEES & SOLE MANUFACTURERS, COPYRIGHT, OTIS KING S and PATENT No 183723. The upper end cap is stamped MADE IN ENGLAND around a central ventilation hole. The base cap is stamped with the serial number C 1371. The instrument is accompanied by its original stitched brown leather cylindrical carrying case.
Length: 150mm (closed).