"Emil Busch AG Optische Industrie" is a former German company located in Rathenow (north-west of Berlin).The BUSCH compasses were manufactured only during a limited period in this large company that mainly produced optical instruments. This company had been founded around 1800 by a preacher called Johann Heinrich August DUNCKER to make spectacles glasses. He transmitted the company in 1824 to his son Eduard DUNCKER. The latter having no children, he gave to his nephew Emil BUSCH in 1845 the company that was called in the meantime "Optische Industrie-Anstalt, Rathenow". E. BUSCH had joined the company five years before after having studied optics and commerce. He sold the company on October 22, 1872 to a limited company. It was then renamed "Rathenower Optische Industrieanstalt (former Emil Busch) AG" and he became one of the directors. The name changed again on August 14, 1908 and was then "Emil Busch AG Optische Industrie".During WW II, the company's code name was cxn.
At the same time, the owner founded a parallel company in Göttingen (West-Germany) in 1949 and the name changed again in 1953 to become "Emil Busch GmbH, Göttingen".
This dry compass was made of Bakelite. All WWII compasses featured a counter clockwise 6400 mils scale.