CHAPTER V

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ELECTRIC OSCILLATIONS AND ELECTRIC WAVES.

The conception of an æther—The phenomena of light require the assumption of an æther—The velocity of light—Interference of light—Two rays of light can produce darkness—An electric current—The phenomena of electricity require the assumption of an electro-magnetic medium—Properties and powers of an electric current—Alternating and continuous electric currents—Electromotive force and electric strain—A Leyden jar—The oscillatory discharge of a condenser—Oscillatory sparks—Transformation of electric oscillations—Hertz oscillator—Production of a wave of electric displacement—Detection of electric waves—Metallic filings detectors—The coherer—Inductance and capacity of circuits—Electro-static and electro-magnetic energy—An induction coil—Electric oscillations give rise to electric waves—The electron theory of electricity 185

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