"H" Edinburgh Student Microscope, by W. Watson & Sons Ltd, London, c.1930

The instrument is supported on trunnions on a tripod, inscribed with the manufacturer's name and address, on a shaped wooden board. The angle of the limb can be locked in place with a tightening screw operated by a steel lever. The monocular body is carried on a rack and pinion on the upper part of the limb. Mill-edged knobs on each side of the mechanism operate the coarse focus. A graduated knob set lower on the rear of the limb controls the fine focus. The eyepiece pushes into an inner cylinder, that can be racked in and out of the body, by two knobs at the front of the instrument. The rotating nose can hold three objectives. The rectangular, mechanical stage has two steel spring clips to hold slides, two knobs to adjust its position and a Vernier scale to measure movement. A condenser mounting with a variable aperture is set below the stage on a rack and pinion with a copper alloy knob for focusing. A copper alloy cylinder also extends below the stage and supports the plano-concave mirror.