"Oh, I have an idea!" suddenly exclaimed Hal, for he and Bud had put
their receivers back on their ears when Cub began to communicate with
"Mr. Crusoe" once more.

"Hold the wireless while I talk with my friends," Cub directed to the
fellow "at the other end of the ether". Then he removed the phones from
his ears, and the other boys did likewise.

"Well, what's your idea, Tee-hee?" the operator demanded with something
of a tone of business challenge.

"Why, all we need is a radio compass," Hal replied. "You know I made one
last summer, although I didn't have much use for it. We can install it on
the boat and make a bee line for that fellow's island if he keeps his
spark busy to guide us."

"Good!" exclaimed Bud. "That'll settle the biggest problem before us."

"Yes," Cub agreed. "You're a regular Thomas Edison, Jr., Tee-hee. I think
we'll have to elect you captain of this expedition."

"If we make it," Bud conditioned with a slightly skeptical grin.

"My opinion, if it's worth anything to you guys," said Cub; "is that we'd
better map out our plan thoroughly before we say anything about it to our
fathers. Then we can put our arguments in convincing manner."

"We must finish our plan to-night, for we ought to start not later than
Wednesday morning," Bud argued. "That'll give us one day to get ready