"3" (f=1mm; high magnification)
"2" (f=5mm; low magnification).
Objective lenses in the stacked configuration. They can be used separately or stacked. As shown, the working distance (WD) is 2mm. Objective #3 WD=8mm.
Lens aberrations were reduced by using stops in all lens paths. Objective stop (B), downtube stop (A).
The optical path of the Gould-type microscope is typical for that era. It consisted of an objective lens system (A), the field lens (B), and an eyepiece lens system (C).
The eyepiece consists of two lenses: top lens, diameter =10mm; Bottom lens, diameter =13mm) separated by a 7mm space
Components of the Gould-type microscope: A: Two-lens eyepiece; B: Fieldlens; C: two objective lenses