Optics of Microscope No. 140. A: Eyelens (dia=8mm, f=25mm); B: Mounting position for the Field lens (dia=18mm, f=40mm); C: objective snout and objective lens; D: additional, brass objectives engraved "3" and "5". The distance between the eye and field lenses is 4.5cm.
Three objectives: unmarked, "3" (c15x) and "5" (c25x)
The objectives can be stored in this velvet-lined fish skin case.