An audience enjoying a magic lantern show.

Engraving depicting an audience enjoying a magic lantern show. The apparatus here differs little from that of Kircher in the 17th century, consisting of a metal box with lamp placed in focus of a concave mirror. Reflected light falls on a condensing lens which concentrates it on a glass slide. Here two lanterns are being used to give dissolving views, and the apparatus is mounted on a wheeled trolley so that the operator behind the screen can alter the size of the image seen by the audience. Dated 19th century. (Photo by: Universal History Archive/Universal Images Group via Getty Images)