Monocular Compound Student Microscope, by S. Holmes, London, Later 19th Century

The eyepiece has two Plano-convex lenses in a copper alloy setting at the top of the copper alloy body tube. No objectives are present although the body tube has an internal thread at the lower end. The limb consists of a copper alloy plate fastened between two trunnions and carries a rack and pinion mechanism that moves a dovetail plate to which the stage is fixed. The stage consists of a rectangular copper alloy plate with a small central stage hole with concentric rings engraved around it. copper alloy springs, to hold slides, are joined by a strip of copper alloy and fixed to the stage by a single screw. Adjustment of the stage is made by a double mill-edged knob at the side of the limb. Below the stage, on an L-shaped arm, is a right angle prism for sub stage illumination. The position of the prism can be altered by swinging the arm or adjusting its inclination. The trunnions are heavy copper alloy plate, set into a V-shaped claw foot on which the maker's name is engraved.