line of similar length and direction. Scientific experiment shows that we move our eye-balls in a jerky, irregular manner, even when we view the most graceful line that can be drawn. Yet it is commonly said by all of us that one line delights the eye and the other does not. Evidently, therefore, the difference must lie in that function of seeing which the brain performs. But the brain, too, is a physical organ. It, too, can become fatigued, and it finds certain kinds of work less fatiguing than others.
Psychologists have suggested that a graceful line is pleasant to look at because the regularity and smoothness of its changes in direction make it easily perceived as a complete unity. Thus in the diagram facing page 39, lines A and B are pleasanter to look at than lines C and D, because their character as lines can be grasped by the mind more quickly and more easily than the character of C or D. And, for the same reason, lines A and B taken together make a more pleasing combination than lines B and C or lines C and D.
Now, if you will shut the book and try to draw any one of these four lines, even in your imagination, you will discover that you remember A and B almost perfectly, while you can hardly remember a single part of either C or D. This proves that in your own case the business of seeing has been more successful with graceful lines than with ugly ones. And, of course, successful effort is always more pleasing than failure.
Our working definition of good pictorial composition, offered in the preceding chapter, may be adapted here. Let us put it this way: A beautiful line or combination of lines is one in which we can see and
