Compound Microscope, by Thomas Grubb, Dublin, c. 1860

The microscope is carried on trunnions on the copper alloy and mahogany base. The heavy limb is also of copper alloy and mahogany. For coarse focusing a triple mill-edged knob extends and retracts a bar, with a triangular cross section, on which an arm holding the body is mounted. Fine focus is effected by a lever at the rear of the limb that acts on the stage. The body tube is angled near the eyepiece and is set in a collar with four screws to adjust alignment. The nosepiece is fitted with a revolving mounting for three objectives. The circular stage has a spring clip to secure specimens and a rack and pinion mechanism at its edge enables the stage to be rotated. An illuminating prism is mounted on a semi-circular dovetailed groove that allows it to be positioned above or below the stage.