Part 25

Interrupted extent, illusions of, 48

Iris, 15

Irradiation, 120 and brightness contrast, 114 varieties of (Boswell), 122 in architecture, 199

James, 170

Jastrow, 80

Jones, L. A., 223

Judd, 86, 93

Judgment, 1

Karrer, 160

Kepler, 8

Light, effect of spectral character, 189

Lighting, illusions of depth and distance due to, 102 contrasts, 154 diffusion, effect of, 145 direction, effect of, 144, 151 ending of searchlight beam, 160 warm and cold colors, 158

Lipps, 10, 11 dynamic theory of, 99

Location in visual field, effect, 44

Mean distance theory, Brunot's, 101

Mechanical, esthetic unity, 11

Magician, 3

Magic, mirror, 205

Marine camouflage, 222

Mason disk, 132

Mirage, 3, 176

Mirror magic, 205

Miscellaneous color effects, 140

Moon, apparent size at horizon, 8, 36, 169 theories of, 173 apparent radius of crescent, 121

Müller-Lyer illusion, 53, 93

National Research Council, Committee on Camouflage, 234

Nature, 164

Necker, 74