This slider is situated in the drawtube, well above the insertion of the objective. A sliding aperture can cover the lens. It has two positions: Open and with lens/aperture.
Eyepiece consisting of two plano-convex lenses and a Nicol prism. The prism mechanism can be removed via the side thumbscrew.
Components of the eyepiece: A: Field lens. Dia=2.5cm, f=5.2cm, B: Eye lens. Dia=1.3, f=2.5C: Analyzer.
The Analyzer mechanism also has this very fine cross-hair.
The Ross 2inch objective lens. It has serial number 21134.
Microscope body tube with integrated Nicol prism (A).