This type of brass compass was manufactured by at least 2 companies: Cruchon & Emons, and Plan Ltd. Neuchatel Switzerland.
They represent an early (circa WW 1) attempt at a mirror compass, with an (originally) polished brass insert in the cover which allows the card (w/ bearings printed in reverse) to be read while sighting on a target. This brass "mirror" in this compass is nickel plated.
The bottom of the case is stamped "Made in Switzerland". The compass is used, but still poining North strongly.
These compasses were purchased by the U.S. Engineer Corps for the US Army during WW 1. The top of the lid is then marked US Engineer Corps and the compass has an individual serial number. This compass has not, so it's a civilian one.
Contains Radium paint. (0.18 micro sievert/h)