Compound Microscope, by Duc de Chaulnes, French, Mid-18th Century

The stage is wood in a brass frame with a brass annulus at the stage hole. It stands on four shaped legs, which are attached to the wooden base. Screws at each corner of the base allow the level of the instrument to be adjusted. A plano-concave mirror is mounted at the centre of the base. Behind this the square cross-sectioned lower pillar is set. Below the level of the stage two bars extend vertically from the lower pillar to form front and rear sections of the upper pillar. A rack and pinion attached to the stage raises and lowers the upper pillar for coarse focusing. A screw with a mill-edged knob raises and lowers the front section for fine focus. Two collars attached to this section support the brass body in rings. Specimens are held in a screw clamp. A mechanism of racks and screws allow the specimen to be precisely moved. A pointer on a graduated disc on the end of the stage allows the movement across the stage hole to be measured. The instrument stands on a tray lined with decorated paper.

Accessories are kept in a separate wooden box (inventory number 47449) and include: five objectives, a rectangular black plate, a screwdriver, a pin with a wooden handle, brass forceps, stage forceps, a four ml measuring cylinder, a wooden eyecup, a lens mount (no lens), nine glass slides and three wooden sliders, one of which is opaque.