The magic lantern, is an early type of image projector employing pictures painted, printed or produced photograpghically on transparent plates (usually made of glass), one or more lenses , and a light source. It was mostly developed in the 17th century and commonly used for entertainment purposes. It was increasingly applied to educational purposes during the 19th century. The magic lantern was in wide use from the 18th century until the mid-20th century, when it was superseded by a compact version that could hold many 35 mm photographic slides: the slide projector.