<P> Smoke and mirrors is a classic technique in magical illusions that makes an entity appear to hover in empty space . It was documented as early as 1770 and spread widely after its use by the charlatan Johann Georg Schröpfer, who claimed the apparitions to be conjured spirits . It subsequently became a fixture of 19th - century phantasmagoria shows . The illusion relies on a hidden projector (known then as a magic lantern) the beam of which reflects off a mirror into a cloud of smoke, which in turn scatters the beam to create an image . </P> <P> The phrase "smoke and mirrors" has entered common English use to refer to any proposal that, when examined closely, proves to be an illusion . </P>

Where does the term smoke and mirrors come from