en he wondered whether he had gone back, and at last the idea struck
him as strange that the party had not fired a gun at intervals to
attract their attention.

He had just arrived at this point, and was considering whether a light
he saw was a luminous fungus, when a strange noise saluted his ear, a
sound that for the moment he supposed to have come from the forest.
Then it seemed to be in the cave, and he was about to spring up, when he
realised that the noise was made by Billy Widgeon, who was too tired to
let his nervous and superstitious dread trouble him any more, and was
now sleeping as heavily as if he were in his bunk on board the _Petrel_.

Mark felt a curious sensation of irritation against a man who could go
off to sleep so calmly at a time like this, but the man's words came to
mind about his father and mother, and at last Mark was fain to say to
himself, "If the poor fellow can sleep why shouldn't he?"

For his own part he had quite come to the determination that he would
get what rest he could as he lay awake watching, for he knew that,
anxious as he was, it would be impossible to sleep. Besides, he wanted
to listen for the possibility of a signal being made. A gun fired
would, he knew, be heard an enormous distance, and it would give him an
idea of the direction in which the camp lay.

All this while Billy Widgeon lay snoring loudly, but by degrees, as Mark
watched the stars that seemed to float over the jungle, the heavy
breathing became less heavy, and by slow degrees softer and softer till
it quite died away, and all was perfectly still to Mark Strong as he lay
watching there.

But it was only in imagination that he watched, for nature had played a
trick upon the lad, and in spite of his determination to keep awake, in
spite of his anxiety, had poured her drowsy medicine upon his eyes.

For Mark had fallen into as deep a sleep as his companion.

CHAPTER THIRTY NINE.

HOW THE ROARING SPOT WAS FOUND.

Ha, ha, ha! Ha, ha, ha!

Wauck! Wauck! Wauck!

There was a loud rustling of palm leaves, and Mark Strong and Billy
Widgeon sprang to their feet and stared at one another as the warm glow
that precedes sunrise penetrated the cave and lit up their faces.

"What was that?"

"I don't know. Did somebody call?"

"I--I thought I heered them things again," said Billy in a whisper.
"Why, Mr Mark, sir, you've been asleep!"

"I'm afraid I have. Have you?"

"Dunno, sir. Well, I suppose