Wireless telegraphy is based upon the principle of creating and detecting waves in a great pool of ether.
Modern scientists suppose that all space is filled with an "imaginary" substance called ether. The ether is invisible, odorless, and practically weightless. This ether, however, bears no relation to the anaesthetic of that name which is used in surgical operations.
It surrounds and penetrates all substances and all space.
Fig. 193.—Little Waves spread out from the Spot.
It exists in a vacuum and in solid rocks. Since the ether does not make itself apparent to any of our physical senses, some of these statements may seem contradictory. Its definite existence cannot be proved except by reasoning, but by accepting and imagining its reality, it is possible to understand and explain many scientific puzzles.
A good instance is offered by the sun. Light and heat can be shown to consist of extremely rapid vibrations. That fact can be proved. The sun is over 90,000,000 miles away from our earth and yet light and heat come streaming down to us through a space that is devoid even of air. Something must exist as a medium to transmit these vibrations; it is the ether.
Let us consider again the pool of water. The waves or ripples caused by throwing in the stone are vibrations of the water. The distance between two adjacent ripples is called the wave length.
The distances between two vibrations of light can also be measured. They are so small, however, that they may be spoken of only in thousandths of an inch. The waves created in the ether by wireless telegraph apparatus are the same as those of light except that their length usually varies from 75 to 9,000 feet instead of a fraction of a thousandth of an inch.
