784 THE POPULAR SCIENCE MONTHLY. 



slow ones are more voluptuous and allied to the richer varieties of 

 passive sensation. In following straight lines, and in tracing the out- 

 lines of objects, the eye has, it is obvious, a choice out of an indefinite 

 number of velocities of movement. It is probable, for the reason just 

 given, that under these circumstances it usually prefers a slow to an 

 excitingly rapid species of movement.* 



For a similar reason those directions of ocular movement which 

 answer to easy and habitual muscular action, have more of a pleasur- 

 able character than those which soon approach the threshold of fatigue. 

 Thus, an horizontal line is, as a rule, in itself, and apart from any ex- 

 traneous consideration, more enjoyable, because more restful, than a 

 vertical. Let the reader compare the feelings he has in looking at 

 architecture, in which the vertical direction predominates, and at the 

 approximately horizontal lines of a flat landscape. A somewhat anal- 

 ogous difference exists between movements of the two eyes with 

 strongly converging and with parallel axes. The sweet repose of dis- 

 tance arises in part from this comparatively relaxed form of muscular 

 activity. 



So much as to the pleasure of single ocular movement. Let us now 

 see how a pleasant succession of movements is to be secured. The 

 conditions of agreeable sequence of movement seem to be the combina- 

 tion of the refreshing and stimulating element of change with an ele- 

 ment of smoothness or ease of transition. Change of movement is, of 

 course, necessitated by the universal condition of mental life, and vari- 

 ety is the very essence of all aesthetic experience, all monotonous feel- 

 ing being wearisome. On the other hand, a chain of varied movements 

 may be smooth and agreeable, or jerky and harsh, and this difference 

 is related to the innate mechanical conditions of movement, and to the 

 effects of habit. 



Change of movement may most easily be secured by a variation ■ 

 either of velocity or of direction.! One and the same movement may 

 vary in velocity, as in watching the ascent or descent of a projectile 

 thrown up vertically. So different movements may present a differ- 

 ence of velocity as in the sequences of a ballet. Such conti-asts plain- 

 ly answer to tbe most favorable mode of expending motor energy. 

 Again, our movement may be followed by another of different di- 

 rection ; that is to say, one that involves the action of fresh muscular 

 elements, or a change in the relative amounts of action of two or 

 more combining muscles. All complicated movements of objects and 

 all arrangements of lines in the figures of bodies supply such variation 

 in abundance. 



So much as to change of element. Let us now pass to the other 

 condition of agreeable sequence, namely, smoothness. The first and 



* A certain rapidity is no doubt made natural by the need of visually construing 

 objects as wholes. 



f Change of duration and extent of movement will be best spoken of later on. 



