isturbed. If you keep
tossing things in quick succession into the water you will get a
correspondingly quick succession of waves. The law governing wireless
waves is exactly the same. Their length depends on the velocity of the
wave and the frequency of the oscillations that cause it. Or to put it
another way, in order to reckon a wave length you must determine its
velocity (which is not impossible when you remember that sound travels
about one thousand one hundred and twenty feet every second) and the
number of vibrations the particular note causing the wave is making
per second. Now science has been able to compute just how many
complete vibrations a certain note, key, or pitch as you may please to
call it, makes each second, or how many times the particles of air
vibrate back and forth when that especial note is sent out.

"Suppose, for example, a note makes 240 complete vibrations a second
while traveling 1,120 feet; if we divide 1,120 by 240 we shall get
4.66 as the wave length of this note. So it is the pitch to which a
note is keyed that helps determine its distance; and the force
employed to start the note sent out through the magnetic field. That
is why a message projected into the ether from a high-power station
carries a greater distance than one sent from a station where the
power is weaker. It is by power and pitch, then, not by length that we
gauge wireless waves. Do you see that?"

A chorus of assent greeted the question.

"That's bully!" Bob announced boyishly; then blushed at the
undignified ejaculation.

"Don't you be fussed, young man," smiled Mr. Crowninshield. "We're all
of an age here."

"I quite forgot," apologized the tutor.

"That is exactly what I want you to do," returned the master of
Surfside. "Ignore us old people. We are only listening in, anyway, and
have no earthly right to be here."

"Still, I wish to treat you with----"

"It's all right, Bob. We understand," put in Mrs. Crowninshield
reassuringly.

"Well, then, if you will excuse me I'm off again," replied the boy.
"And now that we've got wave lengths settled to our satisfaction we
must remember some other things. One is that sound travels not only
through the air but through the water. In fact, sounds are louder
under water than they are above it. Water is not only a better medium
for carrying sound but also, since it contains fewer obstructions,
sound waves travel farther through it. Another thing which we must not
forge