"What's that? I don't see any such thing around here?"

"You are it."

"What? I'm what?" answered the fat boy, plainly puzzled.

"You are the signal tower in this case. That is, you will stand here
and watch me. When I give a signal you will receive and pass it on to
the others."

"What kind of signals?"

"That's what I'm trying to tell you, if you will give me the chance.
When I hold up my hand, it means that they are to stop letting out
rope. When I move it up and down, it means they are to let out on the
rope a little. Understand?"

"Oh, yes; that's easy. When they shake their hand, it means you want
to go up or down," exclaimed the lad enthusiastically.

"O Chunky, you're hopeless. No, no! Nothing of the kind. Listen.
When I move my hand up and down, just like this--Understand?"

"Sure."

"That means I want to go down further. They don't wave their hands at
all, at least I hope they don't while I am hanging in the air. Now,
do you think you understand?"

"Yes, I understand."