Description

T.G. Co. Ltd. MkIII (Mark III) Prismatic Compass in brass manufactured by F Barber & Son (1932) Ltd for The Gramophone Company Ltd. Comprises compass dial, prismatic sighting mechanism, foldable prism, lid and sight, rotating bezel, transit lock and thumb loop. War Department broad arrow. (Compasses manufactureed by F Barber & Son (1932) Ltd have serial numbers prefixed with the letter “B”.)

The compass is used by lifting the lid and raising the prism. The prism is used to view a distant object against the sighting wire in the lid and simultaneously reading the bearing on the dial below. The bezel can be rotated to mark a specific bearing. This enables the user to keep the compass aligned with a target without constantly needing to re-read the numbers. A small, knurled screw on the side of the brass body is used to secure the rotating bezel into a specific position once a bearing is set. A transit lock is engaged by closing the lid.

This compass was collected by Professor Roland Paxton.