This compound microscope consists of two components: the optical tube (with three lenses), and the brass base with reflecting mirror. The optics are typical of that era, having an objective, field, and eyepiece lenses. Imaging is relatively low magnification (with these lenses).
The split flange screws into the top of the base. Focusing was accomplished by sliding the body tube up or down.

The illuminating mirror is single-sided and flat. The diameter is 2.0cm.

This drum microscope is 22–24cm tall.
Another member of the microscope compendium is this Drum Microscope