Tubes, connected in parallel, [234]
Tuning, curve, [117];
sharp, [214];
with series condenser, [224]
Undamped waves (see continuous waves), [86]
Vacuum tube, [35], [40];
characteristics of, [67];
construction of, [205];
modulator, [239];
three-electrode, [41];
two-electrode, [42]
Variometer, [108]
Vibrating string, study of, [154]
Vocal cords, [153]
Voice frequencies, [163]