“That’s a good idea,” declared Hal.  “Suppose you and Cub go and leave Bud and me here to look after the camp and watch for developments?”

Mr. Perry did not reply at once.  Something new seemed to have slipped into his mind and appeared to be giving him some concern.

“On second thought,” he said after a few moments of silence; “I’m inclined to withdraw my suggestion.”

“What’s up now, dad?” Cub inquired.

“I was just recalling a portion of Hal’s cousin’s diary,” his father replied.  “According to that, it seems that rough characters visit this place sometimes.”

“Oh, we’re not afraid,” Hal protested.  “Besides, you could make the trip there and back in a few hours.”

“Well, we’ll think it over and decide in the morning what we’ll do,” said Mr. Perry.

“Meanwhile, I tell you what we ought to do,” Bud proposed.  “It’s an hour before dark and we’d have time to bring Hal’s wireless outfit up here and hook it up before the sun sets.”

“That’s a peach of an idea,” declared Cub, jumping to his feet in his eagerness.  “I’ve got two hundred and fifty feet of extra wire and some insulators on the boat and we can put up an aerial here without taking down the one on the Catwhisker.  Then we can shift the radio outfit back and forth to the island and to the boat as we please.”

“Good!” exclaimed Hal.  “I’m with you on that.  Let’s get busy and not waste a minute of daylight.”

They worked rapidly, and as they were well supplied with material and tools the progress made by them measured up to expectations.  They fashioned a two-wire antenna with the spreaders left on the island by Hal’s cousin; connected a lead-in to this, and then Cub and Bud climbed the two trees and, with the aid of ropes tied around their waists and the guiding assistance of their companions below, drew the “ether-wave feeler” up to a lofty elevation and fastened it as nearly taut as they could stretch and hold it.  In this work they took due consideration of the professional objection to tree entanglements in aerials so that the insulators were well beyond the reach of the longest limbs.

“It’s a simple matter now to bring the outfit ashore and hook it up with the aerial,” said Hal.  “Let’s do it.”

Enthused by the novelty of their enterprise, they continued the work, even though dusk was rapidly gathering.  Several electric-battery flash-lights were produced, so that the twilight did not seriously hinder them.  By the time the stars had become a billion glittering gems in the sky, the hook-up had been completed with Hal’s sending and receiving set on a table that had been transported from the yacht to a convenient position directly under the aerial and near the opening of the tent.

“Now, let’s see what’s going on in the air,” said Cub.  “Hal, you take the first whirl through the atmosphere.”

Hal sat down by the table and put a pair of phones to his ears.  Then he began to tune.  First there came to him a discordant confusion of static and other noises, including an admixture of “ham impudence”.