Wireless Telegraphy and Telephony/Chapter 1
Wireless Telegraphy
Chapter I
The Secret of Wireless Telegraphy
1. Nature’s Wonderful Medium
The term wireless telegraphy is commonly used in contradistinction to the electric telegraph in which it is necessary to employ a wire as an artificial conducting medium between stations.
Nature provides a medium, called the ether[1] through which intelligence may be communicated over sea or land; and by means of which otherwise impossible results are accomplished. The ether exists between the planets and the stars, and all the other heavenly bodies, and has no conceivable end; hence when we speak of the ether, we tacitly refer to the universe.
This infinite sea of ether is continually in a state of intense turmoil, performing its mission of transferring energy, radiated from the sun, to our earth and the other planets, as well as other influences due to myriads of heavenly bodies outside of our own solar system.
Transmission of energy through the ether takes place in the form of wave motion, and these waves are known as electromagnetic waves. Since light is one form of wave motion, we may make use of it in illustrating the presence of ether, by describing the following well-known experiment.
An ordinary electric bell and small battery are placed in what is known as a receiver, the cover being a glass dome, and an air-pump is then started which will eventually pump out all the air from the receiver in which the electric bell is ringing. Although the cover, or glass dome, is over the bell, it can be plainly heard, and the clapper can be seen vibrating rapidly. As the air is pumped out, however, the sound of the bell becomes fainter and fainter, until, finally, it is no longer heard, although the bell can still be seen as plainly as before, and the clapper vibrating as rapidly as ever. Therefore it is very evident that something remains in the receiver after the air has been removed; for, while we cannot hear the bell, we can see it, and we could not see it if there were not some medium to convey the reflected light waves from the bell to the eye.
While the earth’s atmosphere extends but a comparatively small distance, the extent of the ether is infinite.
The universe is a sea of absolute darkness, and if it were possible for us to place ourselves, say, midway between the moon and the earth (in which position we would be over one hundred thousand miles from any air), we would see all the heavenly bodies, and even our own forms, as the light waves would be intercepted and reflected by them; but, otherwise, all would appear as an intense starlit night, with the unusual features of having the sun visible in greatly increased brilliancy, as well as the moon appearing four times its usual size, and the novelty of seeing our own earth rivalling the moon in size and splendor, even under these conditions, more than ten-fold.
Every manifestation of power on the earth at some time came through the ether in the form of waves, and even when we enjoy the cheerful sunshine we are, in reality, experiencing the result of the absorption of the ether waves from the sun by our own persons.
2. Vibrations in the Ether
Light, heat, and wireless waves are electromagnetic waves (and, therefore, wave motions of the ether), the only difference being in their relative rates of vibration; their velocity, in free ether, being the same, viz., 186,000 miles per second. They do not, however, traverse all substances with like velocities.
The sun is constantly disturbing the sea of ether, not by a single train of waves, but by wave trains of varying frequencies, and the higher rates of vibration are so intense that the mind can scarcely conceive them. When we think of 767 trillions of vibrations per second, it has little definite meaning to the lay mind; yet science has devised means to accurately determine so high a rate, which represents the extreme violet of the spectrum, and is the highest rate of vibration which our eyes are capable of detecting. The lowest rate of vibration to which our eyes are sensitive is 392 trillions per second, which represents the extreme red of the spectrum.
Our eyes are sensitive to all the other rates of vibration between the extreme violet and the extreme red and all these complex waves, acting together, produce what we call daylight. The waves which produce a sensation of light when they fall upon the eye are, naturally, called light waves, although the photographic plate is affected by light waves which are outside the rates of vibration to which the eye is susceptible.
When the ether waves impinge upon a body of ordinary opaque mass, it may be warmed, the energy being transformed into heat. While the light waves may produce heat, there are also ether waves called dark heat waves, which come at a rate of vibration much too slow to produce a sensation of light.
We say that glass is transparent because it does not appreciably obstruct the ether waves. We may sit near a closed window and enjoy the warmth of the sun because the glass, being transparent, does not arrest the ether waves, and, therefore, the glass is not warmed; but our own bodies, being opaque, do absorb them, thus producing heat, which our sense of feeling makes manifest to us.
The rate of vibration in the ether, as artificially produced in wireless telegraphy, is extremely slow as compared with that of the light waves, ranging from approximately 1,500,000 to 100,000 per second. The wave length, in any such case, is found by dividing the velocity by the rate of vibration; hence for the extreme violet and for the extreme red, 13000 inch, while those employed in wireless telegraphy vary from about 650 feet to nearly two miles.
As is well known, the ether in proximity to the earth is in continual disturbance, which creates the magnetic field surrounding the earth. This manifests its presence in many ways; the most common is its influence on the magnetized needle of a compass, which causes it to point north and south. Wireless waves are propagated through this magnetic field, and follow the curvature of the earth.
When we contemplate the wonders of nature, and gradually fathom her mysteries, that which before seemed impossible now becomes an established fact, and even so wonderful an art as wireless telegraphy loses its magic when we study into the laws which govern it, and see it take its place, with marvels of the past, in the service of man.
- ↑ This term ether has absolutely no connection with the drug of the same name.