"You're a fine pair of babies," growled Bill. "I'm sorry I brought you along. Ghosts indeed—Wow! what was that?"
Another long ringing peal of laughter sounded through the night. It reverberated against the steep walls of the canyon and was flung mockingly from crag to crag. The boys felt their blood chill as they heard it. There was something diabolical in the merriment of the wild man who, they knew, was making the hideous sounds.
"I'm going back to the other island," declared Sam.
"If you move I'll knock your head off," said Masterson. "It's just a trick of those kids to scare us, that's all it is."
CHAPTER XXXV.
TRIUMPH.
It was midnight. The moon rode high in a cloudless sky, and the camp of the Boy Inventors, to all appearances, was wrapped in slumber. Through the woods came three creeping, cautious figures. Each carried a spade and a sack. They paused by the camp and looked about them.
Then, by the bright moonlight, they saw the bare plateau below. The black barren where the adventurers had been working that afternoon. Masterson was the first to see traces of digging. He seized Eph's arm and pointed.