Capsules, 50, 61, 67
Chagrin, 191

Chain-reaction, 26, 40
Change, least noticeable, 79,
90, 111; effect on attention,
200
Children, experiments in
tapping, 18; indication of
fatigue, 22; reaction-time,
36; thinking-time, 47;
weight judgments, 71; dis-
crimination in pitch, 111;
field of vision, 147; mem-
ory, 215; suggestion, 22,
Choice-time, 39

Clinical observation, 230
Coincidence, in association
of ideas, 236

Coin illusion, 156

Cold, reaction to, 35; sensa-
tions of, 87
Cold colours, 132
Cold spots, 88

Colour, effect on power of
action, 76; sensations of,
120; system of, 122; effect
on feelings, 179
Colour-blindness, 130
Colour-disk, 123

Duration, of tones, 101; no-

tation for, 116
Dynamograph, 74
Dynamometer, 69
Ecstasy, 202

Education, in observing, 8;
in rapid perception, 9; in
reaction and association,
49; in steadiness, 64; of
power, 72; of touch, 85; of
smell, 98; or memory, 210:
see also Cross-education.
Electric baton, 57
Electric shoe, 53,

Emotion, 191; as a source of
illusion, 162

Energy, reserve of, 23
Enlarged angle, 153

Equation, personal, 27, 225;
of colour, 131

Error, in observation, 2; of
prejudice, 2; of

uncon-

scious additions, 4; in ani-
mal psychology,
5; of
untrustworthiness of the
senses, 7; of reproduction,
70; in memory, see Mem-

ory
Exaltation, 191
Excitability, 191
Excitement, 16
Expectation and attention,
199; and suggestion, 217;
effect on astronomical re-
cords, 225

Experiment, nature of, 11;
kinds of, 11; reliance on,
230; introduced into psy-
chology, 251

Extent of attention, 195
Eye and ear method, 226

Flag-foil, 43

persons,

Flash-light pictures, 36
Fluctuating rings, 158
Fluctuating stair, 158
Focus of attention, 194
Force of act, 72
Force of will, 72

Forced association, 42
Fork, electric, 13, 29, 115;
with mirror, 67; for tick-
ling, 78; giant fork for
lowest tones, 102; of ad-
justable pitch, 107; for least
noticeable differences, 108
Fork-record, 14

Free association, 42
Frog, experiments on, 81, 90
Fundamental colours, 126
Fundamental fact of binocu-
lar relief, 169

Fundamental method of ac-
quiring knowledge, 1

Gain by habit, 32
Gain by practice, 31
Galilei, 230

Galton whistle, 103

Game of twenty questions, 4
Gas-capsule, 67

Gauge for steadiness, 64
German type, 38
Girls, see Children
Going up-stairs, 52

Graphic method, 13, 24, 33,
42, 45, 52, 53, 56, 59, 61,
75, 185

Grasp of attention, 195
Grating, 125

Green-blindness, 132, 134
Greys, 120

Guido Aretino, 116

Gun, steadiness in holding,

63
Gymnasium, 72

Habit, curve of, 31
Hallucinations, experiments
upon, 218, 235
Hamilton, 248

Hearing, 101; with two ears,
116

Heart, 185
Helmholtz, 253
Herbart, 242, 248
Highest audible tone, 103;
dependent on intensity, 106
Holmgren test, 137

Hot, reaction to, 35; hot and
cold, 87; hot spots, 88
Hues, 121

Hundredths of a second,
sign for, 15

Ideas, 235

Illusion, Aristotle's, 85; of
skin space, 85; of visual
space, 151; distorted
squares, 153; enlarged
angle, 153; filled space, 154;
inclined lines, 154; parallel
lines, 155; straight lines,
156; of cornice, 156; of
rings, 156; mistake of at-
tention, 157; of coins, 158;
of depth, 159; of distance,
159; of sky, 160; of moon,
160; of Yale clock, 162;
experiments upon, 218
Imagination, 235

Inaccuracy, see the various

experiments

Inclined lines, 159

Magician's training, see
Robert-Houdin
Magnesium oxide, 159

Map of hot and cold spots, 88
Mariotte, 148

Marker, see Time-marker
Marking time, 53

Material of psychological in-
vestigation, 231
Materialism, 240

Mathematics in psychology,
250

Mediate association, 215
Memory, 203, 235

Mental time, see Reaction-
time, Thinking-time

Mental work, effect on ac-
tion, 23

Metaphysical mania, 202
Middle tone, 113

Mirror fork, 67

Mixing yellow and blue, 128

Mixture of colours, 123

Mnemonics, 213

Racing and reaction-time,
33

Railways and colour-blind-

ness, 136

Rapidity of tapping, 16; of
thought and action, 44; in
telegraphing and typewrit-
ing, 51

Reaction-key, 29
Reaction-time, 25; in disease,
33; runner's, 34; to touch,
35; to temperature, 35;
to light, 35; decreases with
age, 36

Recognition-time, 37
Recognition of letters, 38
Recording-drum, see Drum
Recuperation, 32
Red-blindness, 132
Regard, point of, 145
Relaxation, 32, 189
Reserve of energy, 23
Rhythmic action, 52
Ring illusion, 156
Robert-Houdin, 9, 217
Romanes, 5

Room, isolated, 28; reaction-,

Singing, accuracy of, 67; of
intervals, 68

Size, and distance, 159; and
suggestion, 219

Skin, see Touch

Sky illusion, 160; shape of,
160

Slant writing, 24
Sleep, 238

Smell, 92; threshold of 93;
see also Odours
Smells, effects of, 76
Smoked drum, see Drum
Smoothness, 86
Snapper-sounder, 119
Sorrow, 191

Sound, reaction to, 28
Sounds, 101; effect on grip,
75

Space, touch, 83; auditory,
118; visual, 145

Spark-coil, 15, 20, 23, 43, 45,
47, 54
Spectrum, 124
Sphygmograph, 186
Spiritualism, 240
Sportsman, 45
Spot, blind-, 148

Spots, hot and cold, 88

Squeeze, see Power

Stairway illusion, 156

Standard white, 124

Steadiness, 61; gauge for, 64;
in singing, 67

Stereoscope, 165

Stimulation, 189

Straight line illusion, 156
Strength and will, 72

Strife, of nostrils, 95; binocu-
lar, 174

Suggestion, 217

Suggestion blocks, 219
Symmetry, 182

System of colours, 122; of
greys, 120

Tap counter, 21
Tapping, 15

Taste without smell, 96
Tastes, 76, 96