HOW WIRELESS WORKS.

Kaipara and Waitemata Echo, 21 August 1914, Page 2

HOW WIRELESS WORKS.

(By GAKRETT P. SERVISS.)

More truly than any other tele- ( graphic device, the wonderful wire- . less is a speaking voice. It makes , itself heard just as the human < voice does, by a series of waves . moving freely through space. I From the beginning of time it hasp always been possible for man to \ speak across the sea, if he had known, - how to employ the electric waves that were at his disposal. But he started at the wrong end. He began to use the electricity for conveying intelligence by sending a current of it along a wire. He- pressed a button at one end of the line,and thej electric current passing along the wire . induced a corresponding motion in a tapper at the other end. It was a roundabout way of employing an agency which we now know can be employed more simply and directly by throwing away the wires and making the electric waves "speak" straight through the ether. It is true that the language employed does not consist of the words of any spoken tongue, but it is one that can be directly translated into any other kno vvn to man, and so it is the most universal of all languages. Now let us see how it is employed. First as to the electric"mouth." When a charge of electricity is accumulated on a "condenser,'' a similar, but opposite, charge is induced upon another condenser placed near. The air between them acts as an insulator because it is • a poor conductor of electricity. But when the charge attains a certain degree of intensity the strain upon the air becomes too great, and a spark passes between the two condensers, by which equilibrium is re- j stored between them. The passage of this spark produces, so to speak, a. shock in the ether, which, like the explosion of a gun, or the utterance of a sound, sets up a series of waves in the surrounding medium, which radiate away on all sides. These waves in the ether produce the electric "voice." If the sparks are regulated in number and frequency the consequent waves are similarly regulated. An instrument for the production of such waves is called an oscillator or exciter. It is a kind of vocal apparatus for speaking through th 3 ether instead of through the air. But, just as we should have no knowledge of the passage of sound waves if we were not provided with ears to hear them, so the electric waves would go unregarded if we had no apparatus for receiving them. The receiving apparatus is called a resonator or detecter. It jnay be situated hundreds of miles from the oscillator, but it will catch the waves as they undulate to it through the ether, and it can be made to reproduce them in an audible or legible ■ form by causing them to operate a Morse dot-and-dash instrument, as in ordinary telegraphy by wire. But the electric voice and the electric car are in some ways more manageable than the human voice and ear. We can only produce and hear air waves of s. limited range of frequency, and we cannot do much to alter that limit. Sound waves vibrating less than forty times per second or more than 4.0,000 times are inaudible to us. But electric waves varying in frequency from a few hundred up to hundreds of millions per second can be rendered perceptible, and it is also possible to so construct the instruments that the^ will send forth and receive particular ranges of waves and be mute and deaf to others. Then the distance over which the electric waves can be detected is almost infinitely greater than that of ordinary sound waves. It takes a strong-voiced man to make his words audible across a little river, but, as everybody knows, the electric cry of a ship in distress can be electrically heard from the middle of the 'Atlantic Ocean. And there are enthusiasts who predict that before very long we shall be able to speak by wireless to some other planet, if only there is somebody there to hear and understand us !