THE PERCEPTION OF SPACE, (ill.)

343 projected will be distorted into two different ellipses. If the two parallel lines be projected upon the ceiling or floor far in front, the farther ends will diverge; and if the three parallel lines be thrown on the same surfaces, the upper pair will seem farther apart than the lower. Adding certain lines to others has the same distorting effect. In what is known as Zollner's pattern (Fig. 7), the long parallels tip towards each other the moment we draw the short slanting lines over them, yet their retinal images Fig. 7. x. x x x x X X X X X X X '_/_/// S S x x x x x x are the same they always were. A similar distortion of parallels appears in Fig. 8. Fis. 8. Drawing a square inside the circle (Fig. 9) gives to the outline of the latter an indented appearance where the square's corners touch it. Drawing the radii inside of one of the right angles in the same figure makes it seem larger