Wireless Telegraphy and Telephony Simply Explained / A Practical Treatise Embracing Complete and Detailed Explanations of the Theory and Practice of Modern Radio Apparatus and Its Present Day Applications, Together With a Chapter on the Possibilities of Its Future Development

by Alfred Powell Morgan

CHAPTER X. REMARKS. THEORY. ACCOMPLISHMENTS. MAXWELL'S HERTZ'S DISCOVERY. THE FUTURE.

The history of wireless telegraphy and telephony is a striking example of how it is possible for scientists laboring in the field of pure research and stimulated by accumulated knowledge and imagination to arrive at discoveries of the most vital importance. Heinrich Hertz and Clerk Maxwell in experimental effort to attain other results unwittingly laid the foundation of this art.

In 1867 Maxwell proposed the theory that light is not mere mechanical motion of the ether, but consists of electrical undulations. These undulations are partly magnetic and partly electrical. Moreover, according to the theory, the phenomena of electromagnetism and also that of light are due to certain modes of motion in the ether, electric currents, and magnetism, being due to whirls, or body displacements in the substance of the ether, while light is due to vibrations to and fro.

Twenty years later Hertz discovered the most convincing experimental proofs of Maxwell's wonderful theory, and succeeded in producing electromagnetic waves in such a manner that their propagation through space could be examined, and it readily showed that while they were much longer than the ordinary waves of light, they possessed the same properties, were capable of being reflected, polarized, refracted, etc., and traveled at the same speed.

The waves that Hertz produced are the electromagnetic or Hertzian waves of radiotelegraphy.

Many thousand commercial wireless stations dot the face of the earth. Daily time signals, weather reports and storm warnings flash to ships far out in the ocean from government observatories. Late at night, in the midnight hours, when the world is asleep, powerful land stations commence to whisper press dispatches, and the next morning the ocean daily, containing the same news as our morning paper, is laid on the breakfast table of the ocean greyhound. A distress signal sends revenue cutters scurrying along the coast, and brings rescue to hundreds of imperiled lives. The Navy Department issues an order, and a few minutes later it is in the hands of the commanding officer of a fleet, a thousand miles away. Wireless links two continents across a table, and yet this wonderful apparatus is so simple that a sixteen-year-old boy can build instruments with a little guidance and listen to a far-distant station, 1,500 miles away, spell out its news.

FIG. 150.—An amateur wireless telegraph station.

FIG. 151.—The high-power Naval wireless telegraph station under construction at Washington, D. C.