Charles Lincoln was born in 1744 and died in 1807. He began as an apprentice at the Spectaclemaker's Company in 1758, establishing himself on his own in 1762 in Cornhill near de Poultry, London, until 1791 when he moved to 62 Leadenhall Street, also in London until he retired in 1801. He built, in addition to microscopes, barometers, pantographs, and other drawing instruments.

The solar microscope is, in fact, a projector. Using sunlight, you can magnify images on a wall or screen. In a time when electric light did not yet exist and bright light sources such as the spotlight and incandescent lamp had not yet been invented, sunlight was really the only light that could sufficiently illuminate preparations. To catch sunlight, the mirror was mounted on the windowsill or over an opening. The mirror reflected sunlight, passed through the body of the microscope and projected the preparation on the wall. It should be used in totally dark rooms. The solar microscope was invented in the 17th century and was used frequently until the middle of the 19th century, especially in schools and universities.

It consists of two lenses, the condenser that concentrates the sunlight, and a double convex lens that is the one that amplifies itself. The object to be observed is placed away from the condenser so as not to be destroyed by the heat. The tube containing the two lenses is passed through the window of the room, leaving the reflector or mirror outside. It cannot be used for observing opaque objects.

References: "Billings Microscope Collection" pag 22, fig. 40

G. Turner, "Great Age of the Microscope", pag 229-241

G. Turner, "Collecting Microscopes", Chapter 8

H. Moe, "The Story of the Microscope", pag 113-121

Links: https://www.mhs.ox.ac.uk/collections/imu-search-page/record-details/?thumbnails=on&irn=10746&TitInventoryNo=71754

https://www.microscope-antiques.com/solar.html

http://www.antique-microscopes.com/photos/Secretan_solar_microscope.htm

http://www.bononiaemicroscope.com/en/the-microscopes/england/38-dollond-solar-microscope.html