Part 26

Oppel, 9

Painting and decoration, 179

Painter, 2, 179, 186

Parallax, 105

Parthenon of Athens, 196

Persistence of vision, 131

Perspective, 58 in architecture, 198 aerial 165, 183 theory, 98

Photographer, 152

Photography, use in detection of camouflage, 220

Photometer, 156, 217

Pigments, 184

Poggendorff illusion, 85

Protective coloration, animals, 211

Psychology, 2, 6, 157 of light, 193

Purkinje phenomenon, 26, 139

Reflection-factors, 236

Retina, 14, 20 inertia, 130 color sensibility, 138

Retinal rivalry, 140

Retiring and advancing colors, 136

Reversal of mirror image, 205

Rods and cones, 21

Schröder's staircase, 70

Sculpture, 204

Searchlight beam, ending of, 160

Sensation, color, growth and decay, 131

Sense, 1

Shading, counter, for vessels, 224

Shadows, importance in camouflage, 215