Focus is an internal rack & pinion. The rack is mounted to the square support shaft, which is enclosed within the round stand. This arrangement is apparently a later development of the Adams' microscope design.
A notable feature of the Adams microscope is the compass joint on top of the 18cm main support pillar. This allows the microscope to pivot from vertical to a tilted position. The microscope body is screwed into the top of the horizontal support arm (A). The objective screws into the bottom of the same arm. This limb is attached to the rectangular support pillar. Unlike other Adams models, the limb cannot be rotated or tilted.
The condenser is press-fit into the horizontal stage (B), which is fixed to the focus cylinder. The mirror slides along a beam of brass flat stock. The three legs fold together for storage.
There is no provision for "Aquatic" positioning of this instrument.
Rack and pinion of the cantilevered body support arm. It translates via a knob to move the entire microscope body across a sample, much like a mechanical stage.