Aberration, 19
spherical, 122
chromatic, 135
Aerial perspective, 165, 183
After-images, 24, 25, 59, 128, 186
positive and negative, 129
Airplanes, visibility of, 233
camouflage for different types, 234
size of image at various altitudes, 238
camouflage for various conditions, 240
Alhazen, 8
Angles, influence of, 76
various effects of, 81
contours and, 87
apparent effect on length, 91
theories, 98
Animals, protective coloration, 211
Architecture, 195
balance in, 201
Arcs, circular, illusions due to, 86
Areas, juxtaposed, illusions of, 96
Artist, 179
Attention, fluctuation of, 65, 106, 141, 164
Aubert, 49
Auerbach’s indirect vision theory, 100
Aureole, 178
Balance in architecture, 201
Bas-relief, 143
Battleships, 222
Binocular disparity, 105
Binocular vision, 29, 31
Blending of colors in camouflage, 216
Blind spot, 21
Blue light on war-vessels, 230
Boswell, varieties of irradiation, 122
Brightness,
illusions due to
variations in, 107
and color contrasts, 114
apparatus, 115
and hue, 125
sky, 241
Brucke’s theory, 37
Brunot’s mean distance theory, 101
Camouflage, 210
terrestrial, 210
detection of, 215
marine, 222
airplane, 234
Carr, observations on distance illusions, 108
Chromatic aberration, 19, 135
Chlorophyl, 214
Circle, 11
arcs of, illusion, 86
contracting and expanding illusion, 98
Clouds, 235
Color, 124
after-images, 128
blending in camouflage, 216
contrasts and brightness, 114
growth and decay of sensation, 131
illusions of, 156
retiring and advancing, 138
saturation, 154
sensibility of retina, 138
warm and cold, 158
Confusability, 226
Confusion theory of angular illusions, 100
Contour, illusions of, 52
and angles, illusions, 87

Contracting and expanding circles, illusion of, 98
Contrasts, illusions of, 53
simultaneous, 124, 154
apparatus for, 115, 125
color, 114, 154, 188
brightness, 114
Convergence, illusions of, 108, 191
Cord, twisted, illusion, 88
Daylight, artificial, 189
Decoration, painting and, 179
Decorator, 188
Dember, 167
Depth and distance, illusions, 102
Direction, illusions of
ZÖllner’s, 76
Wundt’s, 79
Hering’s, 80
Disk, Mason, 132
Distance and depth, illusions, 102
and size, 35, 104, 166
Distance illusions, Carr’s observations, 108
Double images, 37
Dynamic theory of angular illusions, 99
Enlargement of sun and moon at horizon, apparent, 169
Equivocal figures, 64
Euclid, 8
Extent, interrupted, illusions of, 48
External image, 15, 17, 34
Eye, physiology, 13
position, 30
adjustments, 33
defects, 19
Fatigue, 128
Field, visual, effect of location in, 44
Figures, equivocal, 64
Filters, color, 214
Fluctuation of attention, 65, 106, 141, 164
Focusing, 14
Form of sky, apparent, 166
Fovea centralis, 22, 23, 139
Frames, picture, effect of wood grain, 190
Geometrical illusions, 44
Glare, 119
Grain of wood, apparent distortions due to, 190
Grecian art, 196
Growth and decay of color sensation, 131
Guttman, 175
Hallucination, 4, 72
Halo, 178
Haze, illusions, etc., 103, 166, 183
earth and high, 240
Helmholtz, 13, 74
Hering, 74
illusion of direction, 80
Hue and brightness, 125
Illusions, geometrical, 44
equivocal figures, 64
influence of angles, 76
of depth and distance, 102
irradiation and brightness contrast, 114
color, 124
light and shadows, 144
in nature, 164
in painting and decoration, 179
mirror, 205
camouflage, 210
Image
after-, 24, 25, 59, 128, 129, 186
double, 37
external, 15, 17, 34
retinal, inversion of, 16
of airplane, size at various altitudes, 238
Indirect vision theory, Auerbach’s, 100
Intaglio, 143
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
Oppel, 9
Painting and decoration, 179

OTHER BOOKS
BY
M. LUCKIESH

COLOR AND ITS APPLICATIONS

Second Edition, Revised and Enlarged.

6 x 9, 150 illustrations, 4 color plates, 431 pages.$4.50

The object of this treatise is not only to discuss the many applications of color, but to establish a sound scientific basis for these applications. The book is authoritative, well illustrated, and contains many references and a wealth of new material. It was written by an investigator in the general field of color and is therefore not narrowly limited in scope. It fills a distinct gap that has existed on the book shelves.

LIGHT AND SHADE AND THEIR APPLICATIONS

6 x 9, 135 illustrations, 277 pages$3.00

The book is a condensed record of several years’ research by the author in the science of light and shade. It is the first published work which deals with the science of light and shade in a complete and analytical manner. The author has the faculty of bringing forth scientific facts in such a manner as to be helpful to those interested in the various arts. The book is of extremely wide interest because it deals with the appearances of objects and hence with vision and with lighting. It is well illustrated and represents the first elaborate attempt to formulate the science of light and shade and to correlate it with various arts.

ULTRAVIOLET RADIATION, Its Properties, Production, Measurement and Applications.

6 x 9, 12 plates, 270 pages$3.50

It is the primary aim of this book to present authentic data of such scope as to be useful to the chemist, physicist, engineer, biologist, ophthalmologist and physician and others interested in ultraviolet radiation. Theory has been subordinated to experimental facts because the latter are not affected by the inevitable changes in theory. Much of the literature on this subject is confusing because of the lack of care in the choice of definitions and of limited value resulting from carelessness in specifying important factors. From this mass of isolated material the author has coÖrdinated much valuable data. The many references which are included increase the usefulness of the book.

LIGHTING THE HOME

5 x 7½, illustrated, 289 pages$2.00

This is a pioneer book. It ranks with books on interior decoration and furniture as a help toward transforming a house into a home. It is practical in that it offers advice on all sorts of lighting problems and it is fascinating reading as well.

ARTIFICIAL LIGHT, ITS INFLUENCE ON CIVILIZATION

6 x 9, illustrated, 366 pages$3.00

This story of the achievements of artificial light is written especially for the man in the street who is not interested in technical scientific terms and formulae, but who looks with admiration upon the huge signs which flash and sparkle above the crowds on the Great White Way, who marvels at the colors and brilliance of a spectacular theatrical production and desires to know how it is accomplished, and who takes a natural delight in hearing about scientific discoveries when they are explained in the simple, vivid language he understands best.

THE LIGHTING ART, ITS PRACTICE AND POSSIBILITIES

6 x 9, illustrated, 229 pages$2.50

This book discusses lighting as engineering plus art, and treats the subject as a branch of interior and exterior decoration. The technical aspect of the subject is not neglected, but the main emphasis is upon the “why” and not merely the “how” of lighting.

THE LANGUAGE OF COLOR

6 x 9, illustrated, 282 pages$2.00

A practical volume on color, the various fields in which it is used and its importance in portraying the ideas that make for progress. A book of special interest to all those who deal in color schemes and values.

THE BOOK OF THE SKY

6 x 9, illustrated, 236 pages$3.50

“The beauties, wonders, awesome spectacles, inspiring panoramas, and extensive ranges of vision which await the aerial traveler, make of cloudland a veritable fairyland if he will open his consciousness to them. Aircraft have brought this new world of experiences within easy reach of mankind and it is one of the aims of this volume to awaken those who fly, or would fly, to the variety of interest which air travel affords.”