As Jo spoke, pressing forward they came to a sudden enlargement along the way, the walls receding on either side. Jo raised his torch for a better view when a grinning skull flashed out of the darkness, nodding and bobbing at them, while a rattling and whirring noise resounded through the cavern.

With a cry of astonishment, Jo let fall the torch which was quenched as it fell upon the floor, and at the same time something big and indescribable struck him full in the face.

So confused were they by the suddenness and unexpectedness of the attack, and encompa.s.sed as they were by the absolute blackness, the first thought of the boys was to run to the entrance of the cave, and this they set about to do with the greatest possible promptness.

But both boys as they started were grappled by unseen antagonists with whom they were locked in a deadly embrace, struggling and straining as they wrestled in the darkness, until Tom almost at the point of exhaustion was roused to a frenzy by the rattling of bones and the feel of a skeleton hand on his arm. With a sudden, not to be denied effort, he threw off his adversary and rushed wildly through the cave, followed by Jo, who had bested his opponent.

In the meantime, Jim and Juarez were still poking in the little mounds near the cave's mouth and wholly unconscious of the trying experience of the two explorers. The commotion and sound of rapidly moving feet aroused them, and almost immediately Jo and Tom appeared upon the scene.

Somewhat breathlessly, both speaking at once, they tried to describe their uncanny experiences.

"Hold on a minute," said Jim. "Let's get the straight of this. We were just about to follow you in, for we found nothing in the little mounds.

Let's know what to expect."

"I will have to go back anyway," said Jo. "I dropped my gun."

"Sure. We'll go with you," replied Jim. "Now what was it grabbed you?"

"It?" replied Tom. "I should say there were three or four of them."

"What were they like?" broke in Juarez. "Spirits?"

"Well, I don't know just what a spirit is like," replied Tom. "But it was a pretty solid kind of thing that he had hold of me."

"Me, too," added Jo. "And it snorted and puffed like a grampus."

"Well, I suppose we are lucky to get off as easy as we did," said Tom, "though I should like to know what they were. I thought the whole lot of skeletons were coming after us, but I don't believe they could do any puffing or snorting. It's time we were getting along."

"We will be ready for them this time, whatever they are," determined Jim, who had been lighting torches so that each could be supplied with one.

"Come on then," said Jo. "We must keep together and be on the lookout."

Arming themselves each with a heavy f.a.got which made a serviceable club, the four bent their footsteps in the direction of the chamber of weird experiences.

The silence in the cave was profound, the occupants, if any, not betraying their presence by the least sound. Cautiously the boys advanced, pausing now and then as they approached the place where the surprise had occurred, to listen and gaze as far as they could into the heavy darkness; but all was silence.

"I think they have gone," said Jo at length, in a voice in which there was a tremor of excitement.

"No, there they are," replied Tom in a whisper.

"Where?" asked Jim.

"There!" responded Tom, indicating several suspended skeletons of full length which were held against the walls, and which the light now revealed.

"Oh," said Jo, "it wasn't them."

"Well, one of them was," returned Tom, "for I felt his hand on me."

"Must have been this one, then," said Jim, kicking a group of bones with his foot. "Here is one of them lying on the floor. You must have knocked him out, Tom."

"Here, Jo, is your gun all right," interposed Juarez.

CHAPTER XIX.

THE CAVE.

The place in which the boys stood was a circular room about thirty feet in diameter, with a height of some twenty feet. There was but one entrance, that by which they had come, but high up on the wall were several small openings or tunnel-like pa.s.sages. Around the wall of the chamber was a row of skeletons, standing stiffly upright. There was a great roughly hewed stone G.o.d or idol on the farther side, while here and there close around it on the surface of the natural stone floor were marks where fires had been built. At either side were pyramidial walls of human skulls, all perfect, though those that formed the bottom rows were black with age.

As the light from the torches flashed into the s.p.a.ce several large bats that were in the openings began to fly wildly about.

"I wonder where they have gone?" said Tom, gazing blankly around. "There was certainly something that had hold of me, but there isn't anything here now."

"What was it like?" asked Jim, suddenly.

"How should I know," returned Tom. "I couldn't see it in the dark."

"But you could feel it, couldn't you?" persisted Jim.

"Why," returned Tom, "I don't know, just like any person I should say."

"And you, Jo," went on Jim. "What was yours like?"

"Why, like anybody, I suppose," was the somewhat indefinite description.

"Now, what is the matter?" demanded Tom, as Jim dropped to the floor in a paroxysm of laughter.

"Oh, ho, ho. It's too funny for anything," returned Jim in intervals of his merriment.

"What is?" demanded Tom.

"The whole business," returned Jim as he struggled to regain control of his feelings.

"Let us in on the funny part," said Tom, a little sourly.

"Well, you see, when you dropped the torch--"

"You mean that's the time we didn't see," put in Tom.

"One of those big bats flopped into your face--."

"Well?"

"Then you two started to run, and, of course, you ran into each other and thought something had gotten hold of you. Oh, ho, ho!" and once more Jim was doubled up in his paroxysms of merriment.

"I guess you are right, Jim," said Jo, somewhat sheepishly, but joining in the laugh. "I think the joke is on us."