Mutual inductance, [109];
variation of, [110]

Natural frequency, [161]

Nitrogen, [10]

Nucleus of atom, [10], [12]

Ohm, defined, [64]

Organ pipe, [160]

Oscillations, [87];
damped, [114];
to start, [114];
intensity of, [236];
natural frequency of, [117]

Output circuit, [187]

Overtones, [159]

Oxygen, percentage in air, [10]