Solar Microscope, by Banks, London, 19th Century

The instrument is made from copper alloy. The object tube with the projection screws lens to the body. Behind the projection lens is a double slot to take a copper alloy slide carrying objectives. The focusing by a rack and pinion on the side of the object tube (the teeth appear to be worn). A sprung cylinder pushes against the stage plate. On the lower side of the copper alloy stage plate is a dovetail slot to take condenser lenses in copper alloy slides. The object tube screws into the narrow end of a condenser tube which is divided into two parts: one is cylindrical; the lower part opens into a conical shape. They carry a field and a condenser lens. The larger end of the conical tube has an external screw thread which fits the hole in the centre of the square copper alloy plate which can be fixed to window shutters by two shutter screws placed at diagonal corners. A large rectangular mirror is mounted on a movable circular plate, concentric with the axis of the instrument and attached to the square shutter plate. The vertical inclination of the mirror is adjusted by a screw and rack arrangement mounded on the circular plate. The screw protrudes though a semi-circular slot in the lower half of the shutter plate. The position of the mirror is adjusted by an internal screw arrangement that rotates the circular plate carrying the mirror. The adjustments for the mirror are both effected by means of wing nuts.