The eyepiece (R) consists of a single biconvex lens (dia = 20mm, f=28mm) mounted in a wooden support tube. This, in turn, is mounted on a fish skin-covered cardboard slider tube. The tube is decorated with gold toolings.
The eyepiece cover (L) is wood, possible Lignum vitae.
The objective is a single biconcave lens (dia=7mm, f=4mm) that sits, unglued, in a wooden holder. The holder is threaded to screw onto the microscope body. Note the small aperture (2mm dia); especially compared to the diameter of the lens itself.
Objective attached to body.
Microscope No. 127 optics:
A: Biconvex eye lens
B: Biconvex Field lens
C: Biconvex objective lens
Biconvex objective lens, dia=7mm, f=4mm.