But the two aged brigands never got another chance to attempt to rob the boys and the professor. Why this was we shall soon see.
The next morning, on account of the watch that was kept, nothing was found disturbed.
“We fooled somebody that time,” observed Ned.
After breakfast the professor announced that he was going to visit the house where he had, on a previous call, captured the gila monster.
“There was a cabinet there I overlooked,” he said. “Do you boys want to come along?”
“There is nothing else to do,” said Jerry. “How I wish we would hear something from Bob! I think we ought to go out on a search for him. It doesn’t seem that he will ever come here, after all this time.”
“I was thinking that myself,” said the professor. “If we hear nothing by to-morrow we will leave this place.”
The boys accompanied the naturalist to the ruined house. It seemed strange to be walking through the streets of a place that had been inhabited thousands of years ago. The city was a silent one, a veritable city of the dead, and the houses and buildings seemed like tombstones that had toppled over from age.
As Ned was walking about through the lower rooms of the house the professor had marked for exploration, he noticed a ring fastened to a square stone in the courtyard.