Billie followed as fast as he could and as he stepped beneath the roof started back in the utmost amazement, for up through what looked like a huge well there came the distinct sound of human voices.
For several seconds he stood as one in a spell and then he started forward to peer into the well, but on a second thought did not.
"I couldn't see anything if I did," he thought, "but any one looking up could see me. I'll do better by listening."
The words came to him almost as distinctly as though he were in the same room with the speakers, and there was no longer any doubt that the voices were those of the Zapatistas who had attempted to rob the train.
From their conversation Billie learned the outcome of the fight, and he was greatly amused at the attempt of the bandits to figure out who had betrayed them. Each one had a different theory, but all agreed that there must have been a traitor in the band. It was all the lad could do to prevent himself from calling out to them, just to see what effect his words would have.
After discovering from the conversation that the bandits felt themselves perfectly secure where they were and that they were likely to stay there for some time, he finally decided to get back to the railroad and thence to Pachuca and give the alarm.
Acting upon the decision, he made his way across the basin to where he had slid down the embankment and slowly and laboriously climbed to the top, followed by Ab.
Retracing his steps, he soon reached the railroad and looking down the track toward Pachuca gave a shout of delight as he saw his three chums approaching, leading a fourth horse between them.
"Just in time," he said, as they drew near enough to exchange greetings.
"Just in time for what?" queried the others as one.