Binocular optics
This Swift & Son microscope has a binocular eyetube.
Binocular optics consist of A: mirror, and B: image splitting prism.
The image formed by the objective is split by the two-sided prism into two slightly shifted images. These shifted images are reflected by the internal mirror into the two eyetubes.
Internal mirror for reflecting the images into each eyetube.
Image shifting prism.
Image prism in place just above the objective. Note the angled top surfaces.