Magic lantern slipping slide

Magic lantern slipping slide of a photographer taking a photograph of a woman on a beach who is surprised by a donkey.

Two glasses are mounted in a wood frame. The action is produced by moving one glass, the 'slipping glass', in front of the second glass, which is fixed. The slipping glass is free to move across in a lateral direction and can be pulled partly out of the frame and pushed into its former position.

The subject may be represented on the fixed glass in two distinct positions. The illusion of movement is effected by alternately masking one and then another part of the picture. Used to give an impression of movement, to show two states of a similar object, or to give a ‘quick change’ effect often with comic results.