The illustration shows the type of theatre use of the illusion which John Henry Pepper pioneered and repeatedly staged in the 1860s: short plays featuring a ghostly apparition which interacts with other actors. An early favourite showed an actor attempting to use a sword against an ethereal ghost, as in the illustration. To choreograph other actors’ dealings with the ghost, Pepper used concealed markings on the stage floor for where they should place their feet, since they could not see the ghost image’s apparent location. includes such detailed explanation of his stagecraft secrets, disclosed in his 1863 joint application with co-inventor Henry Dircks to patent this ghost illusion technique.