island and had many adventures while hunting
and otherwise. They found out that the father of Slogwell Brown,
always called Slugger by his comrades, was laying claim to the island.
This man, backed up by Asa Lemm, a discharged teacher of Colby Hall,
and backed up likewise by his son Slugger and Nappy Martell, did all
he could to take possession of the property. But the Rover boys
exposed the plot, and held the rascals at bay, and in the end old
Barney Stevenson's claim to the land was made safe. During the time on
the island Slugger Brown and Nappy Martell had stolen a tin box
containing some valuable papers from the old man, and for this they
had at first been threatened with arrest, but had been allowed to go
when Slugger's father gave up his claim to the place.

"You think you're smart, don't you?" Slugger Brown had grumbled to
Jack when he was ready to depart from Snowshoe Island. "You just wait,
Jack Rover! I'm not going to forget you and your cousins in a hurry!"

"And I won't forget you either," Nappy Martell had added. "We'll get
even with you when you least expect it."

But for quite a while now none of the Rovers had seen or heard
anything more of Slugger Brown and Nappy Martell. But they were
destined to hear more from these two unworthies, and in a most unusual
fashion.

CHAPTER III

THE AMMUNITION FACTORY EXPLOSIONS

"Oh, I do hope Mary is safe!" cried Martha Rover, as she and the
others ran toward where the automobiles which had brought them over to
Colby Hall from the girls' boarding school were standing.

"So far those explosions haven't reached Clearwater Hall," answered
her brother Jack. "But there is no telling what a real heavy explosion
may do."

"That's just it!" burst out his cousin Randy. "For all we know, those
Hasley people may have a large quantity of TNT or some other high
explosive stored there, and if that should go up--good-night!"

"It would be fierce!"

"I think it's awful to allow those ammunition people to have their
works so close to a town," was Ruth Stevenson's comment.

_Boom! Boom!_

Two more explosions rent the air. Then followed a series of poppings
like the discharge of a machine gun.

"Those must be some of the small shells going off," said Andy. "Gosh,
what a shame they couldn't have held this back until the Fourth of
July!" he added. Andy would probably have wanted to joke at his own
funeral.

The Rovers and their girl friends were soon seated in t