"You can not stay in the cave! You must get out!" was the answer, as a louder crash of thunder than usual seemed to shake the very mountain.

CHAPTER XXIII

ENTOMBED ALIVE

For an instant Tom and his friends paused at the entrance to the wonderful cavern, and looked at the raging storm. It seemed madness to venture out into it, yet they had been driven from the cave by those who had every right of discovery to say who, and who should not, partake of its hospitality.

"We can't go out into that blow!" cried Ned. "It's enough to loosen the very mountains!"

"Let's stay here and defy them!" murmured Tom. "If the—if what we seek—is here we have as good a right to it as they have."

"We must go out," said Professor Bumper simply. "I recognize the right of my rival to dispossess us."

"He may have the right, but it isn't human," said Mr. Damon. "Bless my overshoes! If Beecher himself were here he wouldn't have the heart to send us out in this storm."

"I would not give him the satisfaction of appealing to him," remarked Professor Bumper. "Come, we will go out. We have our ponchos, and we are not fair-weather explorers. If we can't get to the lost city one way we will another. Come my friends."