Lantern Slide, "The Glacier," circa 1885

Magic lanterns use a concave mirror and light source to project images on glass slides with painted or photographic scenes. Developed in the 17th century, magic lanterns predate slide projectors and motion pictures. In the hands of magicians, they became "lanterns of fright," projecting wondrous images and apparitions. Slide themes ranged widely: exotic travel, folklore, advertising, history, science, and art.