Rare 17th C. J.C. Breithaupt Pocket Compass

A very rare antique pocket compass engraved on the dial "J.C. Breithaupt, Cassel" dated 1618. Reverse side is inlaid with copper dots spelling "JOHAN HUSS" and an anchor. Beveled and domed glass crystal, mechanical stop. Note: at some point, a "4" was etched over the "6" in the date. Dials recently re-silvered, excellent working and overall condition. Measures 2-3/4" diameter.