Simple Microscope, by Charles Chevalier, Paris

This drum microscope consisting of an eyepiece, body tube and base. Focusing is by a rack and pinion, which raises or lowers the body tube, guided by two steel screws fastened to it though vertical slots in the cylinder.

The eyepiece consists of two plano-convex lenses set in blackened brass.

The brass body tube carries the maker's inscription

The base is a cylinder, open on one side to admit light and a concave mirror is mounted between two horizontal screws. The cylinder extends to support the stage and body tube. The base has an internal thread, which implies that a lower support is missing.