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