Copper Alloy Drum Microscope in Case, by Georges Oberhaeuser, Paris, Mid-19th Century

Copper alloy drum microscope with case. The compound eyepiece pushes into the top of the copper alloy body tube, which is held in a copper alloy sleeve. A nose with button objectives screws into the lower end of the body. Coarse focusing is by sliding the body vertically. The sleeve is mounted on the top of a cylinder with a section cut away to take the rectangular stage plate. A vertical screw at the side of the cylinder, below the stage, facilitates fine focusing by tilting the plate. A window is cut in the front of the cylinder, near the base, to allow light to the concave mirror mounted on a spindle within. A superstage bull's-eye lens is mounted on an articulated arm held on a dovetail fitting on the front of the cylinder. The instrument screws onto a circular lead weighted base. The mahogany case has green felt facing the supports and green silk padding in the lid. It also contains a second nosepiece.