This small botanical-style instrument utilizes a hinged arm to hold and maneuver the double lens over the circular 1 1/2" opening in the brass stage. Focus is by rack and pinion moving the vertical, triangular support in a circular brass tube.  This, in turn, is attached to a 3 1/2" circular brass base. The 1 1/2" plane mirror is mounted on the base by a screw. The black hinged arm holding the lens is stamped "J. Zentmayer, Phila." lenses supplied are marked "s.l.co. 9x" and "s.l.co. 12x". Overall height = 5 1/2".

Joseph Zentmayer was born born in Germany, in 1826. This microscope is probably from his late period*.

*Thanks to Dr. Hauke Kahl, Applicationspecialist, Business Area Microscopy, OLYMPUS Deutschland GmbH