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