ing about it and how
to use it I shall take it away. I mean it, mind!"

"Yes, Dad," was the timid answer.

With this awful alternative looming like a specter in his path was it
to be wondered at that Dick resolutely turned his gaze from the
allurements of the harbor and settled himself in the big chair with
all his attention focussed on Bob King's radio lesson. Moreover, human
nature is selfish enough to like company in its misery and were not
his mother, Nancy and Walter consigned to the same fate as himself?

Therefore the initial lesson began gayly.

At first Bob, seated in the chair of state facing his class, was shy
and embarrassed; but soon he forgot himself in his subject and losing
his hesitancy he spoke with the authority of one who has mastered his
art.

"I am going to begin," said he, "just as they began with me at the
radio station for I think if you get the principles of wireless at the
outset you will find it much easier to understand it. And to do this
we shall not start with wires, generators, detectors, or anything of
that sort; instead we must go back of them all to the earth and the
air, and learn how it is possible for sound to travel without the aid
of human devices. For in reality there is something that takes the
place of man-made wires. This is the ether. Surrounding the earth
moves the air we breathe; and as we go higher this air becomes thinner
and thinner until, by and by, a height is reached where the air gives
place to ether, a sort of radiant energy that bridges the zone between
the air space that encircles the earth and the sun, and brings to us
its heat. This great sea of ether is made up of particles that are
never still and which are so small that they get between every
substance they encounter, thereby becoming a universal medium for
transmitting light, heat, color and many other things to our earth.
Without this body of ether, there would be no agency to pass on to us
(as well as to the many other planets of our solar system and those
outside it) the energy the sun generates, which is the thing that
keeps us alive."

Bob waited a moment to make sure that his point was clear and then
proceeded:

"Now this energy as it moves through the ether takes the form of
waves; and these waves go out not in a single train but since the
ether is continually disturbed by the sun, in series of wave trains
that vary in frequency. Such waves are electromagnetic in character,
and light, heat,