Optical components of microscope 276

A: Eyepiece, plano-convex, dia=25mm, f=40mm
B: Field lens;
C: Objective
The field lens is a plano-convex lens set in an ivory collar fixed to a cardboard tube. dia=43mm, f=16.5cm.

Note the line on the tube (arrow) that is the presumed position of the field tube within the microscope body.

Field tube (B) position within the microscope body (A). This places the field lens 40mm from the eyepiece lens (the focal length of that lens).
Objective lens (A) is held in place within an ivory mount by a metal snap ring. Note the small (2mm) aperture (end of arrow A).

Objective lens dia=6mm, f=7mm.