ill no reply.

"I cornered him, proved he was an impostor, and now he won't talk to me
any more," said Hal, addressing his companions. Then he translated the
code conversation, just completed, for the benefit of Mr. Perry.

"Well, that disposes of him for the time being, at least," was the
latter's comment.

"But leaves a mystery as to his identity," put in Bud with a
"mystery smile".

"No, I don't think there's any question as to his identity."

"Have you worked it out by mathematics, dad?" Cub inquired.

"Yes, by sines and cosines."

"What are sines and cosines?" asked Hal.

"You'll find out when you go to college and study trigonometry," Mr.
Perry replied.

"Oh, I've seen those words," Cub answered, with some of his alleged
characteristic "highbrow eagerness". "You spell sine, s-i-n-e, and
cosine, c-o-s-i-n-e."

"Exactly," smiled Mr. Perry. "Those are terms used in higher mathematics.
But, in order that you youthful minds may not work too hard over my
trick, I'll admit that in my mind I spelled sine s-i-g-n, and cosine,
c-o-s-i-g-n."

"No use to try to get ahead of my father," Cub declared, shaking his
head. "He could prove that water runs uphill by mathematics. He means the
signs and cosigns indicate that--. What do they indicate, dad? We got off
the question just because you wanted to carry your point with a pun."

"I meant to say that this fellow whom you cornered and chased out of the
air is one of the fellows who hazed Hal's cousin by marooning him on this
island," Mr. Perry answered.

"Gee! that never occurred to me," exclaimed Cub, swinging his long arm
with a snap of his finger like the crack of a whip. "I bet anything
you're right."

"We get one step nearer every time we make a move," said Bud eagerly.

"Yes, but the question is, how many steps do we have to take before we
settle this--this--mystery?" Cub demanded.

"Don't look ahead so far," Mr. Perry warned. "Here's a rule in such
matters that applies to all men--and boys--of small or large capability.
Be careful never to look ahead so far you can't see the step you are in
the act of taking."

"All right," Cub assented. "What is the next step for us to take?"

"Find out who the fellows are that hazed Hal's cousin." Bud replied.

"Yes, that's a good suggestion, though it'll probably require several
steps to gain that information. Still, you're not looking so far ahead,
when you propose that move, as to be unable to see your first ste