A large mid 19th Century crab tooth duplex with dual time dials and a compass in a silver full hunter case. Gilt three quarter plate keywind movement with going barrel, the plate decoratively cut away to show the train. Engraved shaped cock with polished steel regulator, uncut bimetallic balance with spiral hairspring. Crab tooth duplex escapement, the steel escape wheel with two locking teeth so that the watch will appear to beat seconds. Screwed in jewelling. Fully restored signed white enamel dial with subsidiaries for two time zones, the left with Roman numerals, the right Arabic numerals. Below these a small glazed compass marked with the cardinal points. Seconds beating centre seconds, blue steel hands. Engine turned and engraved silver full hunter case, the front cover with a vacant rectangle. Maker's mark “AJ” in an oval, wound and set through the silvered metal cuvette engraved with the retailer's name and “Duplex – Ten jewels & ruby roller”. Lateral stop slide in the engraved band.