He had now reached a low spot in the natural rocky wall. He felt that if he could once get a glimpse at this point he might see something that would help him and Rosemary.

And to his great delight, when he had sauntered, as casually as he could make it, to an observation point, what he saw made him gasp for breath.

For, grouped closely together, below him, on a sort of big table of rock, were a number of the Yaquis. They appeared to be holding a sort of council or parley, and were gathered about an Indian to whom Mike and Paz often delegated certain duties.

But this was not what caused the heart of Floyd to thump so desperately against his ribs, making such a noise, he wildly feared, that the pounding would be heard by some pa.s.sing Indian.

What caused him fairly to gasp for breath was the sight of a great boulder, poised on the edge of the natural wall, and hanging almost directly over the group of talking Indians.

"If I can push that rock down on them it will do the trick!" thought Floyd. "It'll put some of 'em out of business, and the rest will be so frightened that they'll retreat. Then whoever is out there trying to break through to help us, will have matters their own way. That's what I'll do. Ill pry that rock loose and let it dash 'em on the heads."

It was a horrible thing to think of, much more horrible to do, but the situation of Rosemary and Floyd was desperate indeed. The end seemed to justify the means.

"The point is," mused Floyd, "can I shove that rock down?"

Looking about him he saw that he was not observed. He quickly made his way nearer to the rock, and then, reaching out his hands, he pushed.

Gently at first he exerted the pressure, and then putting more power into the shove he thrust with all his might.

"It's giving! It's giving!" thought Floyd, with a desperate catch of his breath. "I can shove it down on 'em and dash 'em all up!"

He exerted all his strength. The rock was moving, and even with all the villainies the Indians had to their discredit Floyd's nerve almost failed him as he saw the great boulder sway as if for the plunge.

But to his chagrin he felt the rock move back toward him again. He tried to hold it away--to thrust it from him--but nature, in the guise of the attraction of gravitation--pulled the rock back into the socket-shaped bed where it had rested so long.

It rolled back with a grinding sound, and Floyd feared, for a moment that he had loosened it so that it would topple back and fall upon his feet.

But this did not happen. The great half-round stone oscillated to and fro and then came to rest. Floyd had only caused it to sway a little.

"Well, I moved it!" he said with a gasp. "I'll try again. If I can only get it started it will do the trick."

Again he pushed, with all his might, but again the same thing happened.

He managed to make the rock sway outward, a little farther over the edge of the wall, but back it came again into its hollow resting place.

Then Floyd understood the nature of the matter.

"It's a balanced rock," he said to himself. "She's been resting here for ages, and you can move it just so far but no farther. It would take a team of army mules to dislodge it."

He looked over the wall again. The Indians were still in the same place, eagerly talking--a score or more of feet below the boy.

"It's too good a chance to miss!" whispered Floyd desperately. "I wonder if I can't find some sort of a lever and pry it loose."

He looked about him. Not far away was part of a dead tree branch, thick as his arm.

"Just what I need!" he exclaimed.

He ran to pick up the branch and, returning with it, set one end under the balanced rock, that was still swaying slightly from his exertions.

"Now for a last try!" murmured the lad.

He bent his weight on the long end of the improvised lever. The rock seemed to rise from its socket bed, and to sway outward. There was an exultation in the boy's heart. He thought, in another instant, that he could send the great stone crashing down into the midst of the Yaquis.

Then, suddenly there came a sharp report, and Floyd felt himself falling.

His first feeling was that he had been shot and that this was the end.

But he felt no pain, save a sudden b.u.mp as he sprawled on the rocks, and then he realized what had happened.

He had pressed so heavily on the old and dried piece of wood that it had snapped and broken with a report like that of a pistol, and he had dropped.

"Too bad!" murmured Floyd.

As he picked himself up he saw two of the Yaqui Indians running around a rocky corner. They had evidently been drawn to the place by the sound.

"No good letting them know what I tried to do," quickly decided Floyd.

"It would only make it worse for us."

Having decided on a line of action it did not take the lad an instant to carry it out. Quickly he picked up the broken pieces of his lever and started back with them toward the cave where he and his sister were held captives.

"Make fire!" he said to the Indians. "Make fire--cook grub!"

"Ugh!" they grunted. They evidently accepted this obvious explanation.

Their suspicions lulled, they turned and went back the way they had come, pausing long enough, however, to watch Floyd enter the cave where Rosemary waited.

"Well," she questioned, as he threw the broken ends of his lever on the rocky floor.

"No go," answered Floyd despondently. "I had a peach of a chance to play a trump hand on them, but luck was against me."

He told what he had tried to do with the rock.

"Oh? I--I'm almost glad it didn't succeed!" said Rosemary with a shudder. "It would have been--terrible!"

"Nothing is too bad for these devils!" cried Floyd. "But I give up. I can't think of anything more to do."

"Then shall I try my way?" asked his sister.

"It is a desperate chance," Floyd murmured.

"But don't you think we ought to try it? We may be able to reach the wall, and get over, or go down the trail we came up. It was too steep for the horses, but maybe we can make it."

The horses had been abandoned by the Yaquis as they entrenched themselves for this last stand. The animals could not make the ascent.

"Well?" asked Rosemary of her brother.

"I'm with you!" he said, with a sharp intaking of his breath.

Then they got ready for the ruse Rosemary had proposed.