Solar Microscope in Case with Accessories, by Benjamin Martin, London, c. 1775-1800

The copper alloy body screws into the back plate. On the rear of the copper alloy plate is a rectangular mirror and two milled knobs on the front of the plate adjust the position and angle of the mirror. The slide carrier screws onto the other end of the body tube. It consists of an outer cylinder with two rectangular sections cut away and a thread in the end to take the projection lens. There is also a slot to take a copper alloy slide with six objective lenses (kept in a black card case). A rack and pinion, for focusing, extends the outer cylinder from an inner cylinder that holds the stage and an third, spring mounted, cylinder. The stage is two disks that are pushed together by the spring cylinder. The accessories are two shutter screws, a copper alloy wet cell, an ivory slider in a black card case. The fitted wooden case has green felt facing the supports.