American Family Educator

MESSAGES WITHOUT WIRES

GUGLIELMO MARCONI
The genius who developed
wireless telegraphy.
Possibly the most conspicuous of all the recent discoveries in science, and farthest reaching in its ultimate effect upon our material affairs, is that of the successful system of wireless telegraphy developed and established by the genius of the young inventor, Guglielmo Marconi. His first experiments resulted in communication at will without wires, over a distance of over 250 miles. The public had hardly become accustomed to this fact when the announcement was made upon the authority of the young inventor himself, verified by unmistakable evidence, that on December 12, 1901, he had received signals across the Atlantic by the same system. The far reaching results of a system by which messages are transmitted without the preliminary stringing of wires or cables, by which ships may be spoken to in rnid-ocean far from sight, by which distress signals, can be sounded from sea to shore, and by means of which continents can be connected without the aid of cables, is almost too stupendous for realization.

A. B. SALIGER
With receiving apparatus
Let us consider the methods by which the sender of the wireless message operates. Those of us who are unfamiliar with electrical apparatus are accustomed to consider only such electrical streams as take their way along wires. But there are a great many other electrical streams unconfined by wires, which can be quite as telegraphic as if they were kept on paths of copper and steel.

Discoveries of this nature were made as long ago as 1842, and others looking in the same direction followed. Marconi makes no claim to being the first to experiment along the lines which led to wireless telegraphy, or the first to signal for distances, without wires. But in spite of his prompt acknowledgment to other workers in his field, it has remained for Marconi to perfect a commercial system, and put it into practical working order over great distances.

THE COHERER

The first two essentials in wireless telegraphy are the vertical wire and the "coherer," which by its exquisite sensitiveness makes it possible to register messages as received. Before the development of the receiving apparatus of Marconi, electricians learned how to develop electrical waves. These waves have long been utilized for sending messages through wires. Marconi started with the assumption that inasmuch as electrical waves may pass through the ether, which fills all space, as readily as through wires, if these waves could be controlled they would convey messages as easily as the wires. Then he undertook to make an instrument that would produce a peculiar kind of wave, and another apparatus which would receive and register this wave at a distance from the first.

GENERATING THE HERTZIAN WAVE.

Interior of experimental station
at the foot of Oak Street.
This wave is called the Hertzian. It is generated by a battery, and passing in brilliant sparks between two brass balls, is radiated to space from a wire suspended on a tall pole. By the shutting off and turning of this peculiar current, the waves are so divided as to represent the dots and dashes of the ordinary Morse alphabet of telegraphy. The waves which come from the transmitter are received on a suspended wire elevated either by a mast, kite or balloon. This wire is exactly similar to the one used in the transmitter, but by the time the waves have passed over a long distance, they are so weak that they could not of themselves operate an ordinary telegraph instrument. For the necessity thus arising, Marconi found a remedy in his coherer. This instrument is a little tube of glass, about two inches long, and as large as a small lead pencil, in diameter. The ends are plugged with silver and nearly meet within the tube. In the space between the plugs there is a small quantity of nickel and silver filings, finely powdered.
MARCONI STATION
The Great Wireless Telegraphy Station
at Glace Bay, Canada.
Towers each 215 feet high,
from which Mr. Marconi flashed
the first wireless sentences.
The filings are jumbled together like the particles of a sand heap, and in that state they form a very poor conductor. When they receive an electrical wave, however, they cling together as tightly as a solid conducting bridge that carries a current from a local battery to a receiving telegraphic sounder of common pattern. If it is connected at one end with the suspended wire and at the other end with the Morse instrument, there is a dot or dash printed, according to the signal that has been sent by the transmitter, miles away. Then a little tapper, actuated by the same current, strikes against the co- herer, and the particles of metal are jarred apart, or de-cohered becoming instantly a poor conductor, and thus stopping the strong current from the home battery. Then another wave comes through space, down the suspended wire, into the coherer, drawing the particles together again, with the result that another dot or dash is printed. After these processes have continued for some time, a complete message may be picked out upon the tape.

TEMPORARY EXPERIMENTAL STATION.
Showing pole and air wires.
In his early experiments Marconi believed that in order to cover great distances, very high masts must be used - the greater the distance, the taller the mast. He thought the waves were hindered by the curvature of the earth, but his experiments have proven that very tall masts are not necessary.

Now that the sensational and "nine days' wonder" period following the invention of the wireless telegraph has passed, and the period of practical development and extension has set in, we shall probably hear much less through the public prints about this really marvelous device, although, before we are fairly aware of it, it will be in general and familiar use throughout the world. That wireless telegaphy has already been brought well within the realm of practical usefulness is evidenced by the fact that the United States government is establishing a system for its own use in Alaska, and that nearly all the ocean steamship companies am equipping their vessels with wireless apparatus. That it is being taken up also as a new and promising field for the investment of capital is evident from reports from the financial world, which state that already scores of companies have been organized for the purpose of operating an extensive system of both wireless telegraph and telephones throughout the United States, Canada and the old world.