Eyepiece for Wollaston Type Simple Microscope, by A. Pritchard, London, c. 1832

The top plate is inscribed with the maker's name and a plano-convex lens pushes onto a short tube at its centre. The lateral position of the lens is adjusted by two mill-edged screws near the rear of the plate. A bar with a square cross section supports an arm with a screw-tightened collar above the lens. The height of the collar is adjusted by a screw with a double mill-edged knob below the bar.