INDEX

• A
• Acoustic clouds, echoes from, 325
• —— reversibility, 461-469
• —— transparency, great change of, 323
• Air, process of the propagation of sound through the, 33
• —— propagation of sound through air of varying density, 41
• —— elasticity and density of air, 54
• —— influence of temperature on the velocity of sound, 55
• —— thermal changes produced by the sonorous wave, 60
• —— ratio of specific heats at constant pressure and at constant volume deduced from velocities of sound, 62
• —— mechanical equivalent of heat deduced from this ratio, 64
• —— inference that atmospheric air possesses no sensible power to radiate heat, 66
• —— velocity of sound in, 69
• —— musical sounds produced by puffs of air, 89
• —— other modes of throwing the air into a state of periodic motion, 91
• —— reflection from heated air, 338
• Albans, St., echo in the Abbey Church of, 50
• Amplitude of the vibration of a sound-wave, 42
• Arago, his report on the velocity of sound, 328
• Atmosphere, reflection from atmospheric air, 335
• Atmosphere, its effect on sound, 365
• Auditory nerve, office of the, 32
• —— manner in which sonorous motion is communicated to the, 33
• B
• Bars, heated, musical sounds produced by, 87
• —— examination of vibrating bars by polarized light, 209
• Beats, theory of, 385
• —— action of, on flame, 387
• —— optical illustration of, 390
• —— various illustrations of, 397
• —— dissonance due to beats, 399, 428
• Bell, experiments on a, placed in vacuo, 36-37
• Bells, analysis of vibrations of, 190, 198
• —— fluctuations of, 351-354
• Bourse, at Paris, echoes of the gallery of the, 49
• Burners, fish-tail and bat’s-wing, experiments with, 277
• C
• Carbonic acid, velocity of sound in, 65
• —— reflection from, 335
• —— oxide, velocity of sound in, 69
• Chladni, his tonometer, 168
• —— his experiments on the modes of vibration possible to rods free at both ends, 174
• —— his analysis of the vibrations of a tuning-fork, 176
• Chladni, his device for rendering the vibrations visible, 178
• —— illustrations of his experiments, 180
• Chords, musical, 432
• Clang, definition of, 153
• Claque-bois, formation of the, 175, 197
• Clarinet, tones of the, 237
• Clouds, sounds reflected from the, 49
• Corti’s fibres, in the mechanism of the ear, 426
• Cottrell, Mr., his experiment of an echo from flame, 339
• D
• Derham, Dr., on fog-signals, 306
• Diatonic scale, 263
• Difference-tones, 404
• Diffraction of sound, 76 note, 78
• Disks, analysis of vibrations of, 187, 198
• Dissonance, cause of, 428
• —— graphic representation of, 430
• Doppler, his theory of the colored stars, 113
• E
• Ear, limits of the range of hearing of the, 106, 118
• —— causes of artificial deafness, 108, 119
• —— mechanism of the ear, 424
• —— consonant intervals in relation to, 426
• Echoes, 48
• —— instances of, 48-50
• —— aërial, production of, 328-329
• —— from flame, 339-340
• —— reputed cloud echoes, 328
• Eolian harp, formation of the, 159-160
• Erith, effects of the explosion of 1864 on the village and church of, 53
• Eustachian tube, the, 198
• —— mode of equalizing the air on each side of the tympanic membrane, 109, 119
• F
• Falsetto voice, causes of the, 239
• Faraday, Mr., his experiment on sonorous ripples, 195
• Fiddle, formation of the, 123
• —— sound-board of the, 123
• —— the iron fiddle, 169, 197
• —— the straw-fiddle, 175, 197
• Flames, sounding, 261, 302
• —— rhythmic character of friction, 260, 301
• —— influence of the tube surrounding the flame, 263, 302
• —— singing-flames, 264, 302
• —— effect of unisonant notes on singing-flames, 275
• —— action of sound on naked flames, 275, 302-304
• —— influence of pitch, 283
• —— extraordinary delicacy of flames as acoustic reagents, 285
• —— the vowel-flame, 286
• —— discovery of a new sensitive flame by Philip Barry, 288
• —— echo from, 339
• —— action of beats on flame, 387
• Flute, tones of the, 237
• Fog, its want of power to obstruct sound, 348
• —— observations in London, 348
• —— fog-signals in, 355
• —— artificial, experiments on, 357
• Fog-signals, researches on the acoustic transparency of the atmosphere in relation to the question of, 305
• —— station at South Foreland, 309
• —— instruments and observations, 309
• —— variations of range, 315-316
• —— contradictory results, 317
• —— solution of contradictions, 317-323
• —— extraordinary case of acoustic opacity, 318
• —— in fogs, 355
• —— minimum range of, 371
• —— its position, 370
• —— disadvantages of the gun, 368
• Foreland, South, fog-signal station at, 309
• —— fog at, 354
• G
• Gaines’s Farm, account of the battle of, 324
• Gases, velocity of sound in, 69
• Gun, range of, for fog-signals, 312-313
• —— inferiority to the siren, 369
• —— its disadvantages as a signal, 368
• H
• Hail, doubt as to its power to obstruct sound, 342
• Harmonic tones of strings, 152-154
• Harmony, 410
• —— notions of the Pythagoreans, 411
• —— Euler’s theory, 419
• —— conditions of harmony, 411
• —— influence of overtones on harmony, 429
• —— graphic representations of consonance and dissonance, 431
• Harmonica, the glass, 176
• Hawksbee, his experiment on sounding bodies placed in vacuo, 36
• Hearing, mechanism of, 424
• Heat, thermal changes in the air produced by the sonorous wave, 60
• —— ratio of specific heats at constant pressure and at constant volume deduced from velocities of sound, 64
• —— mechanical equivalent of heatdeduced from this ratio, 66
• —— inference that atmospheric air possesses no sensible power to radiate heat, 68
• —— musical sounds produced by heated bars, 87
• Helmholtz, his theory of resultant tones, 405, 406
• —— —— consonance, 414, 420
• Herschel, Sir John, his article on “Sound” quoted, 50
• —— his account of Arago’s observation on velocity of sound, 328
• Hooke, Dr. Robert, his anticipation of the stethoscope, 75
• —— his production of musical sounds by the teeth of a rotating wheel, 85
• Horn, as an instrument for fog-signalling, 310-311
• Hydrogen, action of, upon the voice, 40
• —— deadening of sound by, 38
• —— velocity of sound in, 55, 69
• I
• Inflection of sound, 53
• —— case of the Erith explosion, 53
• Interference of sonorous waves, 381-382, 407
• —— extinction of sound by sound, 383, 408
• —— theory of beats, 385, 408
• Intervals, optical illustration of, 440
• J
• Joule’s equivalent, 67
• Jungfrau, echoes of the, 49
• K
• Kaleidophone, Wheatstone’s, formation of, 170, 196
• Kundt, M., his experiments, 344
• L
• Laplace, his correction of Newton’s formula for the velocity of sound, 58-59
• Le Conte, Professor, his observation upon sensitive naked flames, 274-275
• —— on the influence of musical sounds on the flame of a jet of coal-gas, 454-460
• Lenses, refraction of sound by, 51
• Light, analogy between sound and, 45-50
• —— analogy of, 320
• Liquids, velocity of sound in, 69
• —— transmission of musical sounds through, 113
• —— constitution of liquid veins, 291
• —— action of sound on liquid veins, 294, 303-304
• —— Plateau’s theory of the resolution of a liquid vein into drops, 295
• —— delicacy of liquid veins, 300
• Lissajous, M., his method of giving optical expression to the vibrations of a tuning-fork, 93
• —— illustration of beats of two tuning-forks, 390
• M
• Mayer, his formula of the equivalent of heat, 66
• Melde, M., his experiments with vibrating strings, 141, 427
• —— and with sonorous ripples, 194
• Metals, velocity of sound transmitted through, 72
• —— determination of velocity in, 73
• Molecular structure, influence of, on the velocity of sound, 73, 212
• Monochord or sonometer, the, 121
• Motion, conveyed to the brain by the nerves, 31
• —— sonorous motion. See Sound.
• Mouth, resonance of the, 241-242
• Music, physical difference between noise and, 82, 117
• —— a musical tone produced by periodic, noise by unperiodic, impulses, 83, 117
• —— production of musical sounds by taps, 84, 117
• —— —— by puffs of air, 89, 117
• —— pitch and intensity of musical sounds, 90, 92, 117
• —— description of the siren, 97
• —— definition of an octave, 105
• —— description of the double siren, 110
• —— transmission of musical sounds through liquids and solids, 113
• —— musical chords, 432-433
• —— the diatonic scale, 432-433
• —— See also Harmony.
• Musical-box, formation of the, 169, 197
• N
• Nerves of the human body, motion conveyed by the, to the brain, 31
• —— rapidity of impressions conveyed by, 31 note
• Newton, Sir Isaac, his calculation of the velocity of sound, 58
• Nodes, 131-132
• —— the nodes not points of absolute rest, 135
• —— nodes of a tuning-fork, 175, 177
• —— rendered visible, 177, 180
• —— a node the origin of vibration, 251
• Noise, physical difference between music and, 82, 117
• O
• Octave, definition of an, 105
• Organ-pipes, 219, 256
• Organ-pipes, vibrations of stopped pipes, 221, 256
• —— —— Pandean pipes, 224
• —— —— open pipes, 224, 256, 260
• —— state of the air in sounding-pipes, 227, 257
• —— reeds and reed-pipes, 234
• Otolites of the ear, 425
• Overtones, definition of, 153
• —— relation of the point plucked to the, 155
• —— corresponding to the vibrations of a rod fixed at both ends, 165
• —— of a tuning-fork, 177
• —— rendered visible, 177, 179
• —— of rods vibrating longitudinally, 207
• —— of the siren, 415
• —— influence of overtones on harmony, 429
• P
• Pandean pipes, the, 224
• Piano-wires, clang of, 158
• —— curves described by vibrating, 160
• Pipes. See Organ-pipes
• Pitch of musical sounds, 90
• —— illustration of the dependence of pitch on rapidity of vibration, 100
• —— relation of velocity to pitch, 211-212
• —— velocity deduced from pitch, 233
• Plateau, his theory of the resolution of a liquid vein into drops, 295
• Pythagoreans, notions of the, regarding musical consonance, 410
• R
• Rain, reputed power of obstructing sound, 341-342
• —— artificial, passage of sound through, 345
• Reeds and reed-pipes, 234
• Reeds, the clarinet and flute, 237
• Reflection of sound, 45
• —— from gases, 332
• —— aërial, proved experimentally, 258
• Refraction of sound, 51
• Resonance, 213
• —— of the air, 213-214, 256
• —— of coal-gas, 216
• —— of the mouth, 242
• Resonators, 213
• Resultant tones, discovery of, 399
• —— conditions of their production, 400
• —— experimental illustrations, 401
• —— theories of Young and Helmholtz, 404, 406
• Reversibility, acoustic, 461-469
• Robinson, Dr., his summary of existing knowledge of fog-signals, 307
• —— Professor, his production of musical sounds by puffs of air, 89
• Rod, vibrations of a, fixed at both ends; its subdivisions and corresponding overtones, 165, 197
• —— vibrations of a rod fixed at one end, 166, 197
• —— —— of rods free at both ends, 173, 197
• S
• Savart’s experiments on the influence of sounds on jets of water, 457
• Schultze’s bristles in the mechanism of hearing, 425
• Sea-water, velocity of sound in, 70
• Sensitive flames, 274
• Smoke-jets, action of musical sounds on, 290
• Snow, its reputed power to obstruct sound, 344
• Solids, velocity of sound transmitted through, 69, 72
• —— musical sounds transmitted through, 115-116, 122
• —— determination of velocity in, 211
• Sonometer, or monochord, the, 121
• Sorge, his discovery of resultant tones, 399
• Sound, production and propagation of, 32, 77
• —— experiments on sounding bodies placed in vacuo, 36, 77
• —— deadened by hydrogen, 38
• —— action of hydrogen upon the voice, 40
• —— propagation of sound through air of varying density, 40
• —— amplitude of the vibration of a sound-wave, 42, 77
• —— the action of sound compared with that of light and radiant heat, 45
• —— reflection of, 45, 77
• —— echoes, 48-50, 78
• —— sounds reflected from the clouds, 49-50
• —— refraction of sound, 51, 77
• —— diffraction of sound, 53, 78
• —— influence of density and elasticity on velocity, 54, 78
• —— influence of temperature on velocity of sound, 55, 78
• —— determination of velocity, 57, 78
• —— Newton’s calculation, 58, 80
• —— Laplace’s correction of Newton’s formula, 59, 80
• —— thermal changes produced by the sonorous wave, 60, 80
• —— velocity of sound in different gases, 69, 81
• —— —— in liquids and solids, 70-73, 81
• —— influence of molecular structure on the velocity of sound, 73, 81
• —— velocity of sound transmitted through wood, 74, 81
• —— diffraction of, 76 note, 78
• —— physical distinction between noise and music, 82
• —— musical sounds periodic, noise unperiodic, impulses, 83
• —— —— produced by taps, 84
• —— —— by puffs of air, 89
• —— pitch and intensity o£ musical sounds, 90
• —— vibrations of a tuning-fork, 91
• —— M. Lissajous’s method of giving optical expression to the vibrations of a tuning-fork, 93
• —— definition of the wave-length, 96
• —— description of the siren, 97
• —— determination of the rapidity of vibration, 101
• —— and of the length of the corresponding sonorous wave, 102
• —— various definitions of vibration and of sound-wave, 103
• —— limits of range of hearing of the ear: highest and deepest tones, 106
• —— double siren, 110
• —— transmission of musical sounds through liquids and solids, 113-117
• —— vibrations of strings, 120
• —— the sonometer, or monochord, 121
• —— influence of sound-boards, 123
• —— laws of vibrating strings, 125
• —— direct and reflected pulses, 129
• —— stationary and progressive waves, 130
• —— nodes and ventral segments, 130, 133
• —— application of the results to the vibration of musical strings, 138
• —— M. Melde’s experiments, 141, 427
• —— longitudinal and transverse impulses, 144
• —— laws of vibration thus demonstrated, 148, 162
• —— harmonic tones of strings, 152, 163-164
• —— definitions of timbre, or quality, of overtones and clang, 153, 164
• —— relation of the point of string plucked to overtones, 155-156
• —— vibrations of a rod fixed at both ends; its subdivisions and corresponding overtones, 165
• —— —— of a rod fixed at one end, 166
• —— Chladni’s tonometer, 168
• —— Wheatstone’s kaleidophone, 170, 196
• —— vibrations of rods free at both ends, 173, 197
• —— nodes and overtones of a tuning-fork, 175-178, 197
• —— —— rendered visible, 177-179, 197-198
• —— vibrations of square plates, 184, 198
• —— —— of disks and bells, 187-190, 198-199
• —— sonorous ripples in water, 193
• —— Faraday’s and Melde’s experiments on sonorous ripples, 194-195
• —— longitudinal vibrations of a wire, 200
• —— relative velocities of sound in brass and iron, 203, 206
• —— examination of vibrating bars by polarized light, 209
• —— determination of velocity in solids, 211
• —— relation of velocity to pitch, 212
• —— resonance, 213, 253, 256
• —— —— of the air, 213, 256
• —— —— of coal-gas, 216, 256
• —— description of vowel-sounds, 240
• —— Kundt’s experiments on sound-figures within tubes, 244-251, 259
• —— new methods of determining velocity of sound, 247-251, 259
• —— causes that obstruct the propagation of, 306
• —— action of fog upon sound, 307
• —— contradictory results of fog-signalling, 317
• —— solution of contradictions of fog-signalling, 317-318
• —— extraordinary case of acoustic opacity, 318
• —— great change of acoustic transparency, 323
• —— noise of battle unheard, 324
• —— echoes from invisible acoustic clouds, 325, 375
• —— report of Arago on the velocity of, 328
• —— aërial echoes of, 330
• —— demonstration of reflection from gases, 332
• —— reflection from vapors, 336
• —— —— heated air, 337
• —— echo from flame, 340
• —— investigations of the transmission of sound through the atmosphere, 341
• —— action of hail and rain, 341
• —— action of snow, 344
• —— passage through tissues, 345
• —— —— artificial showers, 346
• —— action of fog, 347
• —— fluctuations of bells, 351-354
• —— action of wind, 361
• —— atmospheric selection, 365
• —— law of vibratory motions in water and air, 377, 407
• —— superposition of vibrations, 381
• —— interference and coincidence of sonorous waves, 382-383, 407
• —— extinction of sound by sound, 384, 407
• —— theory of beats, 385, 408
• —— action of beats on flame, 387
• —— optical illustration of beats, 390, 408
• —— various illustrations of beats, 397
• —— resultant tones, 399, 409
• —— —— conditions of their production, 400
• —— —— experimental illustrations, 401
• —— —— theories of Young and Helmholtz, 405-406
• —— difference-tones and summation-tones, 405
• —— combination of musical sounds, 410
• —— sympathetic vibrations, 421
• —— mode in which sonorous motion is communicated to the auditory nerve, 426
• Sound-boards, influence of, 123-124
• Sound-figures within tubes, M. Kundt’s experiments with, 244-251
• Stars, Doppler’s theory of the colored, 113
• Steam-siren, description of, 309
• —— conclusive opinion as to its power for a fog-signal, 370
• Stethoscope, Dr. Hook’s anticipations of the, 74
• Stokes, Professor, his explanation of the action of sound-boards, 124
• —— his explanation of the effect of wind on sound, 363
• Straw-fiddle, formation of the, 175, 197
• Strings, vibration of, 120
• —— laws of vibrating strings, 125
• —— combination of direct and reflected pulses, 129
• —— stationary and progressive waves, 130
• —— nodes and ventral segments, 130-133
• —— experiments of M. Melde, 141, 427
• —— longitudinal and transverse impulses, 144
• —— laws of vibration thus demonstrated, 148, 162
• —— harmonic tones of strings, 152, 163-164
• —— timbre, or quality, and overtones and clang, 153, 164
• —— Dr. Young’s experiments on the curves described by vibrating piano-wires, 160
• —— longitudinal vibrations of a wire, 200
• —— —— with one end fixed, 204
• —— —— with both ends free, 206
• Summation-tones, 405
• Siren, description of the, 97
• —— sounds, description of the, 97
• —— its determination of the rate of vibration, 101
• —— the double siren, 110, 411-412
• —— the echoes of the, 330
• T
• Tartini’s tones, 399. See Resultant Tones.
• Timbre, or quality of sound, definition of, 153
• Tisley, Mr., his apparatus for the compounding of rectangular vibrations, 447
• Toepler, M., his experiment on the rate of vibration of the flame, 268
• Tonometer, Chladni’s, 168
• Trumpets, range of, for fog-signals, 313
• Tuning-fork, vibrations of a, 93
• —— M. Lissajous’s method of giving optical expression to the vibrations, 93
• —— strings set in motion by tuning-forks, 142
• —— vibrations of the tuning-forks as analyzed by Chladni, 176
• —— nodes and overtones of a, 171, 197
• —— interference of waves of the, 395
• V
• Vapors, reflection from, 336
• Velocity of sound, influence of density and elasticity on, 54
• —— influence of temperature on, 55
• —— determination of, 57
• —— Newton’s calculation, 58
• —— velocity of sound in different gases, 69
• —— and transmitted through various liquids and solids, 70-73
• —— relative velocities of sound in brass and iron, 203, 206
• —— relation of velocity to pitch, 212
• —— velocity deduced from pitch, 233
• Ventral segments, 132
• Vertical jets, action of sound on, 297, 304
• Vibrations of a tuning-fork, 93
• —— method of giving optical expression to the vibrations of a tuning-fork, 93
• —— illustration of the dependence of pitch on rapidity of vibration, 101
• —— the rate of vibration determined by the siren, 101
• —— determination of the length of the sound-wave, 102, 118
• —— various definitions of vibrations, 103, 118
• —— vibrations of strings, 120
• —— laws of vibrating strings, 125
• —— direct and reflected pulses illustrated, 129
• —— application of the result to the vibration of musical strings, 138
• —— M. Melde’s experiments on the vibration of strings, 141, 427
• —— longitudinal and transverse impulses, 144
• —— Vibrations of a red-hot wire, 147
• —— laws of vibration thus demonstrated, 148, 162
• —— new mode of determining the law of vibration, 148, 150
• —— harmonic tones of strings, 152, 163
• —— vibrations of a rod fixed at both ends; its subdivisions and corresponding overtones, 165
• —— vibrations of a rod fixed at one end, 166
• —— Chladni’s tonometer, 168
• —— Wheatstone’s kaleidophone, 170
• —— vibrations of rods free at both ends, 173
• —— nodes and overtones rendered visible, 177-179
• —— vibrations of square plates, 184
• —— —— of disks and bells, 187-190
• —— longitudinal vibrations of a wire, 200, 255
• —— —— with one end fixed, 204
• —— —— with both ends free, 206
• —— divisions and overtones of rods, vibrating longitudinally, 207
• —— examination of vibrating bars by polarized light, 209
• —— vibrations of stopped pipes, 221
• —— —— of open pipes, 224
• —— a node the origin of vibration, 251
• —— law of vibratory motions in water and air, 377
• —— superposition of vibrations, 381
• —— theory of beats, 385
• —— sympathetic vibrations, 421
• —— M. Lissajous’s method of studying musical vibrations, 433
• —— apparatus for the compounding of rectangular vibrations, 447
• Violin, formation of the, 123
• —— sound-board of the, 123
• —— the iron fiddle, 169, 197
• Voice, human, action of hydrogen upon the, 40
• —— sonorous waves of the, 104
• —— description of the organ of voice, 238
• —— causes of the roughness of the voice in colds, 239
• —— causes of the squeaking falsetto voice, 239
• —— Müller’s imitation of the action of the vocal chords, 240
• —— formation of the vowel-sounds, 240-241
• —— synthesis of vowel-sounds, 242-243
• Vowel-flame, the, 286
• Vowel-sounds, formation of the, 240
• —— synthesis of, 242-243
• W
• Water-Waves, stationary, phenomena of, 136
• Water, velocity of sound in, 70
• —— transmission of musical sounds through, 113
• —— effects of musical sounds on jets of water, 291-292
• —— delicacy of liquid veins, 294
• —— theory of the resolution of a liquid vein into drops, 295, 304
• —— law of vibratory motions in water, 377
• Wave-length, definition of, 96
• —— determination of the length of the sonorous wave, 102
• Wave-length, definition of sonorous wave, 104
• Wave-motion, illustration, 128-133
• —— stationary waves, 133
• —— law of, 377
• Waves of the sea, causes of the roar of the breaking, 88 note
• Weber, Messrs., their researches on wave-motion, 133
• Wetterhorn, echoes of the, 49
• Wheatstone, Sir Charles, his kaleidophone, 170
• —— his apparatus for the compounding of rectangular vibrations, 448
• Whistles, range of, for fog-signals, 313
• Wind, effect on sound, 361
• Wires. See Strings
• Wood, velocity of sound transmitted through, 74
• —— musical sounds transmitted through, 115
• —— the claque-bois, 175
• —— determination of velocity in wood, 211
• Woodstock Park, echoes in, 56
• Y
• Young, Dr. Thomas, his proof of the relation of the point of a string plucked to the overtones, 155
• —— on the curves described by vibrating piano-wires, 160-161
• —— his theory of resultant tones, 404