Chapter XXII. The Boys Face a Mystery
 

"Then how are we going to get out?" asked Ned Rector as the guide's match went out.

"That depends upon how long it takes to dig us out," answered Mr. Phipps.

"Then they know we are here?" questioned Tad.

"Oh, yes. Luckily for us, they do."

"Will they have to dig far--is that pile between us and the railroad very thick?" stammered Ned.

"It looks so. Of course I am unable to say what has taken place on the other side of it. The entire main cross cut may have tumbled in for all I know."

"If it has, what then?" demanded Tad.

"It will take that much longer to get us out. That's all."

"How long?"

"Master Ned, I don't know. No one can answer that question. Perhaps hours--perhaps days," said Tom solemnly.

"But we'd starve in that time," protested Walter.

"One can go without food much longer than one would imagine. People have fasted for more than a month, as you probably are aware. No, boys, they will get us out in time. The only thing that troubles me now is the air," said the engineer.

"What about it?"

"Well, we can't live without air, you know. It seems to be fairly fresh now, but how long it will continue that way there is no knowing. I'll examine the barrier, but keep back out of the way while I am doing so."

The young engineer climbed over the heap of broken rock in front of him, and made a careful inspection of the cave-in that had so effectually imprisoned them in the drift.

He found nothing to encourage him. The condition of the collapse was even worse than he had anticipated.

"Can you pace--measure off by taking a series of long steps?" he asked.

"Yes," replied Tad promptly.

"Then please go back to where the bend in the cut begins, and pace down to where I am."

Tad did so promptly, glad to be able to do something to occupy himself as well as to help relieve the tension for the others.

"Exactly forty paces," he informed Mr. Phipps.

"One hundred and twenty feet, eh?" The engineer made a brief calculation in his mind. "One hundred and twenty feet. H-m-m-m."

"Is it as bad as you thought?" questioned Tad.

"Worse."

"Tell me what you have found?"

"Only forty feet of cave-in between us and freedom. That's all."

"I should say that was enough," muttered the lad.

"Ample."

"Is there anything we can do, Mr. Phipps?" spoke up Ned.

"Not a thing. All any of us can do at present is to wait. Knowing we are here, they will lose no time in attempting to get us out. I wish the telephone were working so we might let them know we are all right. We might as well go back. I'll make a trip out here occasionally to learn if they are making any signals to us. They will do this as soon as they can get near enough to the obstruction to make themselves heard."

"Make signals--how?" questioned Ned.

"We use a code, a telegraph code. They will rap with a hammer then we'll answer them."

"But you have no hammer--"

"No, I'll use a rock to pound with if they get near enough. There's no hurry, however. It will be a long time before there's any occasion to communicate."

Turning back, Tom led the way through the passage to the large chamber which they had but recently left. Arriving there, he directed each of the lads to light a match at the same time so he could make a survey of the room to determine whether it were safe for them to remain there or not.

"See that hole up there?" he exclaimed.

"Yes, what is it?" asked Tad.

"It's a check. You see there must have been a weakness in the strata at that point--perhaps it had already started to check there, when the force of the explosion split it wide open. The opening is large enough to admit a man's body. Hold your lights down here while I examine this rubbish that has fallen through."

They did so, and Mr. Phipps dropping to his knees sorted over the stones and dirt that had fallen from above.

At a muttered exclamation from him, the lads crowded closer.

"Queer, very queer," he mused.

"What's queer?" asked Ned.

"Why, this stuff. It appears to be surface material mixed with pieces of rock of about the same quality as that of which the Ruby Mountain is composed."

"I don't understand--"

"I mean that this material that has fallen in here did not all come out of the solid rock."

"What does that mean?" asked Ned.

"Perhaps nothing so far as we are concerned. I was thinking that if they could not blast through the drift, they might as a last resort, drill down through the surface from above and pierce this chamber."

"How could they locate our position close enough to do that?" asked Tad.

"That would not be difficult. From the maps of the mine Mr. Munson could work out our position as closely as a captain does that of his ship at sea."

It was a ray of hope which the boys grasped eagerly. They tried to forget that they were practically entombed many feet underground, and that days might elapse before they were rescued.

"I'll bet Chunky will hug himself with delight when he finds out what's happened," suggested Walter.

"Yes, he'll probably think it's very funny, our being bottled up or rather down in a corner underground," said Ned somewhat dolefully.

"I didn't mean that. He'll be glad he went hunting instead of coming along with us," corrected Walter.

"Yes, I guess he will," agreed Tad. "He'll have a right to congratulate himself that he has missed an opportunity to fall in."

The lads forgot their predicament for the moment in the laugh that followed.

"I wish we had a light," said one.

"We might build a fire. What's the matter with burning up our hats?" suggested Ned.

"No, we should be suffocated. Don't you know we are sealed up," objected Tad. "We don't want to make any additional trouble for ourselves."

"Yes," agreed the guide. "But it is peculiar that there is so much fresh air here. Now and then I can almost imagine I feel a draft, though I know that is not the case."

"Could we not get a draft through that large crack in the rocks up there?"

"I don't see how, Tad. There is nothing but solid rocks above it."

The lad stepped under the opening, holding up a finger which he had wet between his lips. For a full moment he stood poised like a statue while the other two boys lighted matches that they might the better see what he was doing.

"I don't care what you say, there is air coming from somewhere. There can be no doubt of it. I feel it plainly. Try it and see if you don't agree with me, Mr. Phipps."

The engineer stepped up and went through the same process that the boy had gone through. He repeated the experiment twice more.

"You're right," he exclaimed, letting his hand drop to his side. "Your good sense is worth more than all my technical knowledge and training."

"The next question is to find out where the draft comes from. It must be from the outside somewhere," said Tad hopefully.

"Not necessarily, my boy. Of course it may be drawn down through crevices covering many feet of solid rock before reaching us. Then again, the air may come from some subterranean water course. As you know the mountains are full of them, channel upon channel, some high and broad enough to drive a coach and four through."

"Oh. I hoped--"

"Never mind regrets, boys. Wherever the air comes from makes little difference so long as it really is air. It is saving our lives."

"From what?" demanded Walter.

"From eventual suffocation. Were it not for that we would stand a good chance of dying before they were able to reach us."

The boys were thoughtful for a few moments.

"Hungry?" questioned the engineer.

"Somewhat," admitted Tad.

"We might be more so if we had a chance to think about it," added Ned.

"I've got a package of chewing gum here. Help yourself," offered Mr. Phipps.

The lads were not slow to do so, and in a moment were chewing industriously, laughing and talking at the same time.

"Beats all what a little thing will make a fellow forget his troubles," said Ned. "Now, I remember--"

"Hello, boy!"

"Who said that?" demanded Tad Butler springing up from the pile of rocks on which he had been sitting for some time.

"Said what?" snapped Ned. "I was talking when you interrupted me."

"I thought I heard somebody say 'hello,'" confirmed Mr. Phipps.

"So did I," added Walter.

"And I know they did," said Tad emphatically.

"Hello, boy!"

This time all sprang up, startled.

"Who's playing tricks?" shouted Ned.

"Heard it that time, did you?" asked Walter. "It wasn't I."

"Nor I," chorused Tad.

"Then it must have been Ned or myself," said Phipps. "I'm sure that I am no ventriloquist."

For the moment Phipps wondered if they were all losing their senses. He had heard of men, imprisoned under similar circumstances, imagining they heard voices.

Tad Butler, however, knew that imagination had played no part in this voice. He had heard the voice before. He informed his companions of this fact.

"Heard it before? Where?" exclaimed Ned.

"On top of the Ruby Mountain yesterday," answered the boy.