Page:Jack Heaton, Wireless Operator (Collins, 1919).djvu/124

 between them to carry it. Nor again do we mean that it goes to a single receiver and nowhere else.

For instance, when you talk to a person ordinarily you convey to him your message without wires, but it is the air between your mouth and his ear that carries the message, that is, waves are set up in the air and these are called sound waves. Naturally since the air is everywhere on the surface of the earth the sounds you make travel in every direction.

A better example of wireless is a lighted lamp and your eye, for in this case the lighted lamp acts as a transmitter and sets up very short waves in the ether, which are called light waves and these likewise travel in every direction. The ether is a substance that is 15 trillion times lighter than the air and it fills the whole universe, and when the electric waves set up by a light in it strike your eye the optic nerve carries the sensation of them to your brain and you see the light.

The next thing to know is that light waves and wireless waves are exactly the same kind of waves, that is, both are caused by electric stresses and magnetic whirls in the ether, but