?" asked Sam, presently.

"He meant just what he said," returned Tom. "I'm going to tell Dick,"
and he summoned his big brother without delay.

"I think I can piece this together," said Dick. "I saw Bob Grimes
talking to Dudd Flockley this afternoon, and again after supper. Most
likely Bob got on the trail of something Dudd thinks of doing. He
doesn't want to appear as a tattle-tale and at the same time he doesn't
want to see our machine ruined. So that's why he warned you in such a
queer fashion."

"You must be right," answered Tom. "What shall we do?"

"Nothing, Tom."

"Yes, but we don't want the machine ruined, or even tampered with!"
exclaimed Sam.

"I don't think anybody will touch it," went on the eldest Rover boy.
"After you came up here I got to thinking that maybe Flockley, or
Koswell, or Larkspur, or somebody else, might try to injure the
_Dartaway_, and so I went to see Filbury, the janitor, about it. His son
Abner is helping him around the dormitories, and I hired Abner for fifty
cents a night to sleep in the shed and guard the biplane. Abner has got
a shotgun, and he isn't afraid of anybody; so I reckon the _Dartaway_
will be perfectly safe."

"Good for you, Dick!" cried Tom. "Say, I hope if anybody does try to
injure the machine Abner gives him a dose of shot!"

"I told him not to shoot anybody unless it was necessary," answered
Dick. "But he may shoot into the air, just to scare the intruder and
raise an alarm."

The next day was such a busy one for the Rover boys that they had no
time to do more than look at the biplane and see that it was safe. Abner
Filbury reported that he had slept in a hammock slung beside the machine
and that nothing had happened to arouse him. Nobody but the Rovers knew
that he was on guard. The boys wanted to tell Bob Grimes, but that
individual kept out of the way.

After having settled down in their rooms and to their studies, the three
Rover boys made several flights in the biplane, including one to the
Sanderson farm, where they discovered Songbird calling on Minnie. Both
were seated in a hammock between the house and the barn, and both leaped
up in confusion when the biplane, manipulated by Tom, sailed directly
over their heads. When the Rovers came down in the big field, Minnie ran
to greet them, and, later, she treated them to apple pie and some milk.
Then they set sail once more, leaving their college chum to finish his
interrupted visit.

After this flight