A table is shown on which is a looking-glass. The room is darkened, when
a white arm and a hand brandishing a dagger is seen suddenly to appear
and menace the spectator.
_Explanation._—The glass of the mirror slides out of the frame at a
signal. Behind it is a concave mirror set on the floor at an angle in an
opening in the wall. Within the other room an arm and hand of wax,
holding a dagger, are mounted so as to descend, while brilliantly
illumined, towards the concave mirror.
A person can show his or her face instead of his arm or the false limb,
and something rather laughable than terrifying is recommended for such
experiments to a juvenile auditory.