Optics of Microscope No. 261. A: Objective lens; B: Field lens set into field tube. Lens dia=15mm,
=34mm; C: Eye lens, dia=16mm,
=15mm. All lenses are bi-convex.
The objective lens is set into a concave depression in the base of the
mount. The lens is held in place when the cap is screwed into place.
Assembled objective lens.