CHAPTER IX
A PRISONER UNDERGROUND
"What's to do now?"
The question came from Bob Vilett.
The sinking of the brushwood had ceased, and he and Dave found themselves in water almost up to their chins, in absolute darkness.
"I'm sure I don't know, Bob," was the young diver's response. "We are in a tight box, and no mistake."
"We can't stay here forever."
"True, but if we make a move we may sink deeper than ever, and then it will be all up with us."
A dead silence of several minutes followed. Presently both of the lads grew desperate.
"We'll have to do something, that's certain," Dave began, when of a sudden the driftwood sank once more, and they found themselves struggling wildly in the black waters at the bottom of the hole.
They were soon over their heads, and now found a strong current carrying them they knew not where. They had hold of each other, but soon the force of the water wrenched them apart.
Down and down went Dave, and turned over half a dozen times.
He felt as if he must be journeying toward the center of the earth, when he reached out his hand and struck a series of smooth rocks.
He tried to hold fast, but this was impossible, and in a twinkle he turned over again, and then his feet struck on something of a sandy beach.
Hardly knowing what he was doing, he stepped forward, and then found himself clear of the water.
This set him to running, and on he went until he brought up with much force against a stone wall, and fell back partly stunned.
His feet lay in the water, but his head was on the sand, and thus he remained for fully a quarter of an hour, unable to move.
There was a strange ringing in his ears, and when he at last arose his head ached as if it would split open.
"Oh!" he groaned, and staggered up the sand to the smooth, rocky wall.
Then he fell again, and did not move until half an hour later, when his head felt somewhat better.
Where was he, and how could he save himself?
These questions were easy to ask, but no answer was at hand, and he sank down much disheartened.
Then he suddenly roused himself and called loudly:
"Bob! Bob Vilett! Where are you?"
Again and again his voice was raised, but only a dismal echo answered him.
Was his late companion dead?
It was more than likely.
The tears sprang unbidden to the young diver's eyes, but he dashed them away.
He must save himself, no matter what the cost.
He realized that he had been saved from death by drowning only because he was used to being under water a long time without taking a breath.
All divers practice this art, for possible use should anything become the matter with their diving outfits while at work.
He felt in his clothing and found his water-proof matchbox still safe.
Soon he had a tiny light, and seeing some dry driftwood at hand he set it on fire.
The blaze threw grotesque shadows on the rocky walls around him, but revealed nothing to his gaze but those same walls and the silent, underground stream flowing between them.
He was entombed alive!
Gradually this conviction forced itself upon him, causing him to shiver as if with the ague.
Again he called out the name of his late companion, and again only the dull echoes answered him.
He reckoned that he must be at least a hundred yards from the hole made by the sunken driftwood.
To get back to the hole, therefore, was out of the question.
He thought the matter over for a while, and then, taking up some driftwood for a torch, walked slowly along the sandy shore of the black stream.
Presently he came to a bend, and here found that the stream shot downward, forming an underground waterfall.
"I can't go in that direction," he reasoned. "I want to go up, not down."
The stream was less than twelve feet wide, and did not run so swiftly but what he could cross it without much danger.
Obtaining a fresh firebrand, for the first was now burnt out, he swam over to the opposite shore and began an investigation on that side.
"Hurrah!"
The exclamation escaped from his lips involuntarily.
The firebrand had dropped from his hand into the stream, leaving him in darkness.
Looking at the rocks, he had beheld a thin shaft of light striking down from some opening above.
"An opening! May it prove a way of escape!"
With a prayer for aid on his lips, Dave began to climb the rocks as best he could until he reached a hollow ten feet above the stream.
Here the light was stronger, and by applying his eyes to a long, narrow slit in the rocks he made out a broad cave beyond, the further end of which was wide open to the sunlight.
But how was he to get into the cave?
The opening was not over six inches wide, too narrow for the passage of his body.
The rocks were large, weighing several hundreds of pounds apiece.
To move them would take tools, and he had nothing.
Again in a state bordering on despair, he sat down to review his situation.
At last he leaped up, and clenching his hands, cried loudly:
"I must get out! I simply must!"
The cry was an inspiration, for, getting on his knees, he felt around and found that two of the big rocks were unsteady upon their resting places.
He pulled away at the smaller stones beneath, and soon had them loosened.
He continued his labors, and presently, with a mighty crash, one of the rocks slid down into the stream, disappearing beneath the surface with a splash.
At once the light from beyond shot into the opening. He was free!
His heart gave a bound of joy, and quickly he scrambled through the hole and into the cave beyond.
This was a large affair, being at least forty feet wide and high, and several hundred feet long.
"Now, if only Bob were safe, all would be well," thought the young diver.
Without waiting to light another torch he began to move toward the outer opening of the cave.
But before he had gone half the distance he came to a halt with a cry of dismay.
The cave was crossed by another underground stream, all of twenty feet wide, and flowing onward with tremendous swiftness.
It came out from under one rocky wall and disappeared under the wall opposite.
Taking a bit of driftwood, Dave threw it into the water, and it flashed out of sight instantly.
"I can't swim across that," he thought, dismally. "To attempt it would be foolhardy."
Now what was to be done?
He examined the walls carefully.
They were perfectly smooth, thus affording hold for neither foot nor hand.
"If the stream weren't quite so wide I might jump it," he reasoned. "But I—somebody is coming!"
He was right; somebody was entering the cave from the outer end.
The newcomers were two men, one dressed in the suit of an American business man and the other in the garb of a sailor.
"We'll be alone here and can talk the matter over without fear of interruption," said one of the pair, the man in ordinary clothes.
His voice sounded strangely familiar, and Dave strained his eyes to catch a better sight of him and of his companion.
Then, astonished beyond measure, the young diver dropped out of sight behind a rock bordering the underground stream he had been trying to cross.
The newcomers were Lemuel Hankers, the man who had set sail in the Raven after the sunken treasure, and Pete Rackley, the rascal who in Washington had accused Dave of robbing him!