eiving
its signals. You remember we can make dots and dashes by the key or
switch in the oscillator circuit. When we depress the key we start the
oscillator going. That sets up oscillations in the circuit with the
inductance and the capacity formed by the antenna. If we want a
real-sized stream of electrons up and down this antenna lead (the
vertical wire), we must tune that circuit. That is why I have shown a
variable inductance in the circuit of the transmitting antenna.

What happens when these electrons surge back and forth between the
horizontal wires and the ground, I don't know. I do know, however, that
if we tune the antenna circuit at the receiving station there will be a
small stream of electrons surging back and forth in that circuit.

Usually scientists explain what happens by saying that the transmitting
station sends out waves in the ether and that these waves are received
by the antenna system at the distant station. Wherever you put up a
receiving station you will get the effect. It will be much smaller,
however, the farther the two stations are apart.

I am not going to tell you anything about wave motion in the ether
because I don't believe we know enough about the ether to try to
explain, but I shall tell you what we mean by "wave length."

Somehow energy, the ability to do work, travels out from the sending
antenna in all directions. Wherever you put up your receiving station
you get more or less of this energy. Of course, energy is being sent out
only while the key is depressed and the oscillator going. This energy
travels just as fast as light, that is at the enormous speed of 186,000
miles a second. If you use meters instead of miles the speed is
300,000,000 meters a second.

Now, how far will the energy which is sent out from the antenna travel
during the time it takes for one oscillation of the current in the
antenna? Suppose the current is oscillating one million times a second.
Then it takes one-millionth of a second for one oscillation. In that
time the energy will have traveled away from the antenna one-millionth
part of the distance it will travel in a whole second. That is
one-millionth of 300 million meters or 300 meters.

The distance which energy will go in the time taken by one oscillation
of the source of that energy is the wave length. In the case just given
that distance is 300 meters. The wave length, then, of 300 meters
corresponds to a frequency of one million. In fact if w