scene. In such motion pictures there may be shifts, but there are no breaks. Paths of motion on the screen can remain long in our memories, as though they were fixed lines in a picture. Clearly, therefore, it would not be pleasing to have these remembered lines of motion clashing with those which are being perceived.
So much for the optical effects of single motions coming in succession. Now we must advance to the consideration of several motions going on in various directions during the same moment, which is a more usual situation in the photoplay. Several motions at once may constitute a harmony or a jumble, according to the first demands which they make upon the eye-work and brain-work of vision.
The difference between visual harmony and dis-*harmony seems to depend partly on the fact that a pair of human eyes work together as one, and not as two separate instruments. You cannot look up with one eye and down with the other; you cannot look to the left with one eye and to the right with the other; you cannot look at a distant object with one eye and at a near one with the other. Hence, if you try to look intently at two or more objects crossing each other in opposite directions, your eyes are baffled and the effect is not pleasurable. There is also a conflict in our mental work of seeing, when opposing motions try to claim equal attention at the same time, unless, as we have previously stated, these motions are in some kind of rhythmical balance with each other.
Because of this baffling of eye and brain, therefore, we are displeased by the sight of two automobiles
