"Poor Chunky!" groaned Jerry. "I wonder what they are doing to him now?"
"I guess it was his money-belt they wanted more than they did him," put in Ned. "You know he carried what was left of the five hundred dollars."
"That's so!" exclaimed Jerry, with a rueful face.
"Never mind the money; I have plenty," put in the naturalist. "And don't worry; we'll find Bob yet."
Nothing could be done that night, so the professor and the two boys tried to get what sleep their troubled minds would allow. In the morning they made a hurried breakfast and then held a consultation. It was decided to explore the tunnel by which they had entered the city, and see if it still held the brigands and Noddy's crowd.
Arming themselves, the professor, Ned and Jerry advanced carefully through the big wooden gate. They proceeded cautiously, but no one opposed them. The tunnel was deserted. They came to the hole where they had tumbled down. The inclined plane of planks was there, in the same position as when the cave-in, produced by Murado, had occurred.
"They have probably gone back up here and are running across country," remarked Ned. "Hello!" he exclaimed. "What's that?"
He picked up a small object that lay at the foot of the incline, in the glare of the sunlight that streamed in from above.
"That's Bob's knife," said Jerry. "He had it yesterday. That shows he must have been here since. There is no doubt but that they have carried him away from here."
The professor agreed that this was probably the case. There was nothing left to do, so they returned to the temple.
"I hardly know what to do," said the naturalist. "We might take the automobile and ride off, not knowing where, in a vain endeavor to find Bob. Or we can stay here on the chance that he may escape and come back. If we went away he would not know where to find us.
"Then, too, I am hopeful we may hear something from Noddy Nixon or some of those Mexicans he had with him. Those fellows are regular brigands, and may have captured Bob, thinking we will pay a ransom for his return. On the whole, I think we had better stay here for a few days."
This seemed the best thing to do. With heavy hearts, Jerry and Ned wandered about the old temple, wishing their chum was back with them. The professor began to gather more specimens and made several trips to the old buildings where he got many curios of value.