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 End of the Project Gutenberg EBook of Sound, by John Tyndall