We know, furthermore, that we do not see the passing by of the long strip of film.

We know that it is rolled from one roll and rolled up on another, but that this movement from picture to picture is not visible.

It goes on while the field is darkened.

What objectively reaches our eye is one motionless picture after another, but the replacing of one by another through a forward movement of the film cannot reach our eye at all.

Why do we, nevertheless, see a continuous movement?
The problem did not arise with the kinetoscope only but had interested the preceding generations who amused themselves with the phenakistoscope and the stroboscopic disks or the magic cylinder of the zooetrope and bioscope.
The child who made his zooetrope revolve and looked through the slits of the black cover in the drum saw through every slit the drawing of a dog in one particular position.