Part 2

X. Lighting 144

XI. Nature 164

XII. Painting and decoration 179

XIII. Architecture 195

XIV. Mirror Magic 205

XV. Camouflage 210

LIST OF ILLUSTRATIONS

FIGURE PAGE

1. Principal parts of the eye 14

2. Stereoscopic pictures for combining by converging or diverging the optical axes 41

3. Stereoscopic pictures 41

4. The vertical line appears longer than the equal horizontal line in each case 46

5. The vertical dimension is equal to the horizontal one, but the former appears greater 47

6. The divided or filled space on the left appears longer than the equal space on the right 49

7. The three lines are of equal length 50

8. The distance between the two circles on the left is equal to the distance between the outside edges of the two circles on the right 50

9. Three squares of equal dimensions which appear different in area and dimension 51

10. The vertical distance between the upper circle and the left-hand one of the group is equal to the overall length of the group of three circles 52

11. Two equal semi-circles 53

12. Arcs of the same circle 53

13. Three incomplete but equal squares 53

14. Middle sections of the two lines are equal 54

15. An effect of contrasting areas (Baldwin's figure) 54

16. An illusion of contrast 55

17. Equal circles which appear unequal due to contrast (Ebbinghaus' figure) 56

18. Equal circles appearing unequal owing to contrasting concentric circles 56

19. Circles influenced by position within an angle 57

20. Contrasting angles 57