Baltasar on his pony (Velasquez). How charmingly the boy’s searf and sash, and even his baton, emphasize the diagonal line described by the pony’s spirited attitude. Without any suspicion of the reason, the child catches the buoyant sense of the forward motion expressed in the whole picture. Precisely the same idea is carried out in Guido Reni’s Aurora in a succession of parallel curves across the composition. Long before either of these pictures was painted, however, Raphael had set the example in St. Michael and the Dragon. In this composition the uplifted spear of the warrior angel makes a line parallel with that running the length of his right side and along the right leg, while his sword swings back in a line parallel with the left leg. These devices add to the spirited effect of the attitude.
Repetition is offset, compositionally speaking, by Contrast. This principle, as the word implies, means a direct opposition of elements, light to dark, the perpendicular to the horizontal, the convex to the concave, etc. The main diagonal line of St. Michael and the Dragon (running from upper left to lower right) is offset by the diagonals running directly across them. These contrasting lines may be traced, one across the left arm and left wing of the angel, and another across the outstretched arms of the prostrate victim. In exactly the same way the curve of Lavinia’s uplifted arm cuts across the curve of her swaying body and Diana’s right arm cuts the long line extending from her left hand to her right foot. The drawing of Millet’s Sower is on a similar plan. The predomi-
