"Let's consider a bit," he said to his brother. "We can't go on this way. We've got to mark some of these passages so we'll know them again if we come by. Otherwise we'll get all confused."
"Good idea. Make some scratches on them with your knife. That will do."
Frank quickly did this and they pressed on. Occasionally they called to the man, but he did not answer them now—not even by his mocking laugh. They, however, could still hear him.
"He's leading us on a wild goose chase!" declared Frank at length.
"The first thing we know he'll get back to the entrance and escape."
"Then one of us had better go to the mouth of the cave and either stop him, or else be there to give the alarm when he tries to get out," proposed Andy. "I'll go."
"No, I think we'd better stick together," suggested his brother. "That man is too dangerous for one of us to tackle alone. We may catch up to him any moment now, and I hope he'll give in, and tell us what we want to know."
Without the portable electric lights which they each carried it would have been impossible for the Racer boys to have found their way about the cave. They marveled how it was that the mysterious man could follow the windings and turnings in the dark, but, as they learned afterward, he had been in the cave before.
Back and forth, up and down, here and there, like following some will-o'-the-wisp went the boys. At times they thought they had lost the object of their pursuit, but again they would hear him hurrying on ahead of them.
"Hold on a minute!" suddenly exclaimed Frank, when he had led the way down a steep descent. "I don't like this."
"Like what?" asked Andy, in some alarm.