Compass / Distance reader

Old Compass / Distance reader.

This instrument is used to measure distances on maps. It is made of a tiny wheel that can follow the curves of a road. This wheel is connected to a pointer that shows the measured track on a dial. Some compasses are equipped with map readers with several scales.

(built in the 1950's-60's) displays divisions that allow direct reading of distances on maps with the scales 1:20,000, 1:40,000, 1:80,000 and 1:100,000 on one side while the opposite side has divisions for the scales 1:25,000, 1:50,000, 1:75,000 and 1:200,000.