Tiny Compass Microscope, ~1740
The "Compass Microscope" is named so because of the center hinge, reminiscent of a drafting compass. It was used during the 18th century for inspecting small opaque objects such as fauna or flora. To use the instrument, the user would mount the specimen with the stage forceps and locate it just opposite the lens. The silvered reflecting Lieberkuhn mirror focuses more light on the top surface of the specimen. These microscopes were very popular as pocket field aids for naturalists.
The early type compass microscope seen here is exceptionally small, measuring altogether about 10 cm long. So far, this is the only example known to us. So far the maker and provenience of this exceptional instrument remain unknown.