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