Optics consist of a rotating nosepiece (A) with four objectives, a Field lens (B) and Eyepiece lens (C). The eyepiece and field lenses are mounted into a brass tube and sleeve. This unit screws into the eye cup, which itself screws into the body tube suspending the unit inside the microscope. The tapered end of the body tube screws into the fixed nosepiece top. The lower nosepiece disk rotates on a center spindle. Friction is provided by a leaf spring (arrow). Objectives fix in place via a detent.
Assembled eyepiece/field lens system with eyecup (facing). Note the split field lens sleeve.
Field lens (L) and eyepiece lens (R). Eyepiece tube is tapered and threaded to fit in the eyecup.