size or distance in the abstract and apart from reasoning, but knowing one by experience, it can make a close estimate of the other. It angle and underestimates an obtuse one. is this principle on which the illusions shown in Figs. 3 and 4 depend. A right angle should be much easier to judge, but unless the eye is trained it will go astray considerably. FIG. 7. The average woman cannot judge how much a foot is within several inches, but she can estimate a yard very closely, while with the average man the case is reversed. If some one asked you which was the longer, a horse's head from the tip of his ears to the end of his nose, or an ordinary flour-barrel, you would naturally say the barrel, though the horse's head is the longer. The eye is very easily deceived if it is called on to pass judgment on something that FIG. 8. has not been brought home to it by experience. The landlubber at sea greatly underestimates the distance of passing ships, having no familiar landmarks with which to make comparisons. Truthful men under oath in court often disagree widely as to observed facts, and no doubt with perfect honesty. We will not distrust our eyes, though no doubt they deceive us oftener than we realize. FIG. 9. Even a carpenter, who constantly deals with right angles, will not trust himself to saw a board off without a square if he has to make an accurate fit. Beginners in drawing generally find themselves making all vertical lines lean slightly to the right. The buildings in their sketches topple quite uniformly in that direction, as shown in Fig. 10. The error becomes more evident when the drawing is turned on its side. And still a picture made with a ruler and T-square would lack the artistic quality. An artist would never use a ruler to draw a line by, for he understands that the eye demands something more than mere methodical accuracy of line and angle. There should be an element of illusion in every picture, and the true artist is one who knows how to lines on the eye, for they so designed their The eye constantly overestimates an acute buildings as to counteract such defects of vision. The walls, instead of being vertical, lean in; tall windows are wider at the top than at the bottom; columns swell in the middle instead of being straight; the top lines of the buildings, instead of being strictly horizontal, are considerably higher in the middle, and so on. Without doubt much of the beauty of these classic buildings was due to the recognition of such principles in their construction. Modern architects generally ignore everything of this kind and build strictly by the square, level, and plumb-line. There are fine buildings in every city that have been made to suffer in this way, for, though really well built, their walls appear to lean outward, or their cornices to sag in the middle, and so forth. Fig. 12 is an ingenious illusion in perspective that has been used in various connections for advertising purposes. Looked at in the ordinary way it appears to be a meaningless maze of lines. But hold the page horizontally, a little below the level of the eye, and a certain order will come out of the chaos. Look first in the direction indi cated by 1, then in that indicated by 2, etc. These various instances point the moral that our eyes do not by any means always see things as they are, and that if we are not taught how to accept their reports with a "grain of salt" we shall occasionally be misled more or less. In ST. NICHOLAS for April, 1897, there was an article, "Seeing is Believing," upon this same subject, in which other illusions are given. Some of the ones there given are here omitted. FIG. 12. This is the Horse that pranced and neighed when he saw the Woodman sober and staid who slung the Ax with a shining blade that chopped the Tree of a dusky shade that gave the Wood that heated the Oven that baked the Cake that fed the Doll that lived in the House that Jill built. This is the Knight with the red cockade who rode on the Horse that pranced and neighed when he saw the Woodman sober and staid who slung the Ax with a shining blade that chopped the Tree of a dusky shade that gave the Wood that heated the Oven that baked the Cake that fed the Doll that lived in the House that Jill built. This is the Lady in gay brocade who followed the Knight with the red cockade who rode on the Horse that pranced and neighed when he saw the Woodman sober and staid who slung the Ax with a shining blade that chopped the Tree of a dusky shade that gave the Wood that heated the Oven that baked the Cake that fed the Doll that lived in the House that Jill built. This is the Glittering Cavalcade that rode after the Lady in gay brocade who followed the Knight with the red cockade who rode on the Horse that pranced and neighed when he saw the Woodman sober and staid who slung the Ax with a shining blade that chopped the Tree of a dusky shade that gave the Wood that heated the Oven that baked the Cake that fed the Doll that lived in the House that Jill built. This is the Donkey who loudly brayed at sight of the Glittering Cavalcade that rode after the Lady in gay brocade who followed the Knight with the red cockade who rode on the Horse that pranced and neighed when he saw the Woodman sober and staid who slung the Ax with a shining blade that chopped the Tree of a dusky shade that gave the Wood that heated the Oven that baked the Cake that fed the Doll that lived in the House that Jill built. |