Biunial lanterns
A wide variety of styles exist of which the below is only a small representative sample.
Reproduced by kind permission from the 2003 Christie's of London auction catalogue of the John Finney Collection of Magic Lanterns.
Upright Double Lantern, British
Biunial Lantern, British
Biunial Lantern, British
Biunial Lantern, British
Biunial Magic Lantern, British
Biunial Magic Lantern, British
Biunial Magic Lantern