some animal, human or otherwise, was eyeing the camp with studied
interest, and it was difficult to imagine other than a human being
capable of such interest.

Bud finally came to the conclusion that the animal half hidden in the
shadow of the bushes was a man, and that the latter's interest was
centered in "Captain" Howard, whom he doubtless believed to be held
prisoner within the four canvas walls of the tent.

"I bet he's one of those four men that took Hal and me and marooned us on
that other island," the boy mused. "Of course, he's looking for a chance
to set our prisoner free, but he's doomed to disappointment. My
goodness!"

Bud whirled around suddenly as a new possibility occurred to him,
stimulated by a slight noise like the cautious tread of a man's foot. The
next instant a cry of alarm almost escaped him as he saw a human form
near the entrance of the tent.

"My goodness!" he repeated aloud, but in subdued tone, as he recognized
the approaching youth. "You'd better announce yourself, Max, before you
come onto an armed person under such circumstances as these."

"Armed!" echoed the Canadian youth in surprise. "I thought Mr.
Perry said--"

"Oh, yes, he said we couldn't have his automatic, but I've been busy
making a very effective substitute since I came out here--see?"

Bud exhibited his weapon by drawing back the leather sling, thereby
stretching the elastics to their full capacity. His searchlight he had
switched off after finishing the work on his catapult, and the only
illumination in the open area came from the moon over the tree tops.

"Did you make that out here to-night?" demanded Max in astonishment.

"Sure--why not?" was the other's reply.

"Well, you're some boy, all right. I'd never 'ave thought of it. If
anybody means mischief around here, he'd better look out, with a weapon
like that in your hands."

"You bet he had," Bud returned with a sturdiness of purpose, indicating
to his Canadian friend that he meant business. "And there's at least one
prawler around here already. I'm glad you came out here, for I was just
about to come in and wake up the whole camp."

"Is that so?" whispered Max. "Why, what's doing?"

"I don't want to let on that I know anybody is prowling about," Bud
replied; "but if you'll watch those bushes straight south of here for a
while you'll make out the form of a man half hidden there. He moves a
little every now and then. Be careful and don't let him know you kn