stereopticon

noun

1. A magic lantern, especially one with two projectors arranged so as to produce dissolving views or combinations of images.

   “The stories did not seem to me to touch life. […] They left me with the impression of a well-delivered stereopticon lecture, with characters about as life-like as the shadows on the screen, and whisking on and off, at the mercy of the operator.”

   “Certain unscrupulous individuals grow rich through the manufacture and distribution of suggestive postcards, obscene steriopticon views, and inexcusable books and typewritten pamphlets.”