The optics consist of the standard three lenses: Eye, Field and Objective. The Eye (A) and Objective (C) lenses are biconvex. The Field lens (C) is plano-convex. Eye lens: Dia=2.2cm, f=3.0, aperture=1.8; Field: dia=2.2, f=7.0, aperture=1.5. The body is wrapped with green shagreen. The drawtube is wrapped in green vellum.
Objectives 6, 4, and 3 are probably not part of the original accessories for this microscope. The objective in the foreground has the correct thread size and fits the microscope body.
Focus is a simple friction mechanism. The curved spring rubs against the brass support pillar.