Mr. Bull
had succeeded in backing four feet away from the tree. He would
speedily be able to free himself altogether.

Tom and Dave now came running. They threw their weight and muscle
upon the rope to hinder the captive animal. But that great creature
seemed likely soon to overcome the strength of all those combined
against him.

"Come on!" called Dick, backing away on a new course. "Off this
way, to the next tree behind me. Hold on and pull for every pound
you're worth."

Seeing his opponents plainly engaged in making some new move the
wild animal halted, eyeing them balefully. That hesitation proved
fatal to his immediate freedom, for Dick had succeeded in getting
the rope around the tree behind him. Now he took another quick
hitch, supplementing this with a knot, then another and a third.

"I guess we may all let go of the rope now," Prescott smiled.
"I don't believe the bull can pull successfully against that
triple knot."

Mr. Bull was trying it, at any rate. His angry bellows were almost
as loud as the roaring of a lion. Dirt flew. The beast exerted
its whole power in its efforts to get free.

"The knot will hold," pronounced Dr. Bentley, after a critical
survey. "The great danger is friction, which may wear out that
part of the rope hitched around the first tree. If that happens
we shall all have to run for our lives. Come back here, Prescott!
What are you going to do?"

For Dick, leaving the little group, had started on a run for the
bull.

CHAPTER XXIII

WHAT TAG "BORROWED" FROM THE DOCTOR

"I want to see how the rope is faring," Dick explained.

"If it fares badly," called Dr. Bentley dryly, "you will find
your curiosity possibly fatal. Come back here. It is time for
us to be getting away. I am sorry we have no fire arms, or we
could settle Mr. Bull very quickly. Come along, boys! Come,
Dick!"

But Prescott, for once, didn't prove over, tractable. He went
closer, anxiously studying the condition of the rope wound around
the first tree. Until Dick was ready to go none of his chums
would leave the scene. Dr. Bentley had turned away; but when
he found himself unaccompanied, he wheeled about once more.

"You can't do anything---except run in danger, Dick," the physician
called anxiously.

"I am studying this business trying to find out if there isn't
something that I can do," Prescott replied.

"There isn't," Dr. Bentley assured the boy, walking over to him,