"We'll keep our eyes open, Jack," said his father. "That's a hunch worth attention."

"By golly, Dad, the Inca is following us all right. They're bringing up a litter for him. Four bearers are carrying it."

"We won't look back, Don Ernesto," said Mr. Hampton. "It would injure our dignity to do so. Don't stare, Jack. Thank heaven, the old boy is coming. That means not only that we have got him on the run, but also that Cinto won't attempt any demonstration against us while the Inca is present, in all likelihood."

The terrace was reached, and Jack and Frank at once began setting up the aerial. They had brought along a second umbrella aerial similar to that set up on the battlement of the Acropolis, which had been included in the outfit, and this they proceeded to set up. Then the three, Jack, Bob and Frank, connected up batteries, tube transformer and headphone.

Meanwhile Mr. Hampton was staring covertly at the battlement of the Acropolis, towering high on the distant side of the square opposite.

Would Michac fail them? Or would he carry out his part in the plot successfully? Mr. Hampton was thankful to think that, even if Michac should fail them, they were out in the open where they stood a better chance for their lives in a fight, and, also, that they had already roused a wholesome respect for their power in the b.r.e.a.s.t.s of their enemies.

The boys worked with lightning swiftness. They were grateful for the delay in the arrival of the Inca, whose movements were attended by so many ceremonies that it was a considerable time before he had reached the terrace and was ensconced in a great chair brought out for him by other bearers.

"Put on the headphone, Jack, and try it. See whether our friend Michac is at his post," whispered Mr. Hampton, when the last connections were completed.

Jack complied, adjusting the tuner to the meter wave length at which he had set Michac's instrument. A smile broke over his face, and he nodded to his father.

"Senor Jack, I am ready. My man at the parapet tells me you are at the 'phone. Thanks be to the G.o.ds, that you are safe out of that trap. I have been in agony, lest you be overcome and go to your death. I saw the soldiers move into the palace behind you. Now, if you let me speak to the Inca, I shall do my part."

"Good man," whispered Mr. Hampton, when Jack repeated the conversation.

"I'm beginning now really to hope for success. If he scares the Inca badly enough, we may hope for Prince Huaca's relief."

Approaching the Inca, Mr. Hampton bowed. Then he gestured toward the radio instrument, the installation of which had been watched with absorbing and breathless interest by soldiers, courtiers and counsellors.

"The Lord Beyond the Mountains would speak to you in your own tongue, O Inca," said he. "Will you deign to approach so as to put to your ears this instrument even as the young man has done."

He indicated Jack, who at his father's direction, continued to wear the headphone and smiled invitingly. This, Mr. Hampton had felt, would help to a.s.sure the Inca no evil would come to him from acceptance of the invitation.

"I a.s.sure you no evil will come to you thereby," Mr. Hampton added.

The Inca regarded him with impa.s.sive face. His shrewd eyes sought to read the countenance of this strange magician and to detect whether he spoke in good faith or was attempting deception. He decided Mr. Hampton was honest. Moreover, it would not do for him to show fear.

"Amba.s.sador from the Lord Beyond the Mountains," said he. "I will listen to your master's voice, if, indeed, he can speak to me across the forests and the mountains, and in my own tongue. But woe betide you if this be false."

Signing to the bearers, he was lifted, chair and all, and set down where Jack indicated. Then Mr. Hampton took the headphone, while a n.o.ble, at the Inca's command, stepped forth and, after prostrating himself, removed his crown. Thereupon Mr. Hampton placed the headphone upon the Inca's head.

Stepping back quickly, he raised his hands aloft and looked to the heavens, as if indicating to some unseen spirit overhead that the time to speak had come. In reality, this was a signal to Michac's spy at the parapet of the Acropolis battlement to pa.s.s word to Michac to speak.

The next moment, Michac's voice, sonorous and deep, was heard in the receivers.

"Great guns," whispered Frank, in English, "what a wonderful radio speaker he is. Why, you can hear him plainly."

"Wish I could understand what he's saying," said Jack, excitedly. "Look at these counsellors and courtiers, will you? They get him, and, boy, they're scared stiff."

It was true. Michac had one of those rare voices with a bell-like quality that carries beautifully by radio. And he was obeying to the letter Jack's hasty instructions as to where to place his mouth near the transmitter so as to get the best effect. He spoke in the Inca tongue, and, of course, the boys could not understand what he said.

Nevertheless, that it was having a powerful effect, not only on the courtiers and n.o.bles surrounding the Inca, but on the Inca himself, was apparent.

What Michac was saying, the boys knew in general, for he had been instructed to demand the release of Prince Huaca under threat of dire catastrophes to be visited upon Cusco Hurrin otherwise. But Michac had said that he would make his commands intimate, employing his knowledge of the Inca and the affairs of Cusco Hurrin. And, quite evidently, he was doing so.

The Inca's face became white, his eyelids fluttered, and then his head fell forward.

"Great guns," cried Bob, "he's fainted. The shock was too much for him."

Jack sprang forward and s.n.a.t.c.hed the headphones from the Inca's head.

The audience gasped, and then its fear of these strangers, created by their marvels piled upon marvels, gave way before the deep-seated instinct of reverence for their ruler, the personal representative of their G.o.d. Hoa.r.s.e cries of rage arose, and courtiers, n.o.bles and soldiers, all jumbled together, began to surge forward toward them.

Affairs looked bad, indeed.

At that moment a shot sounded from the direction of the Temple of the Sun. Another followed. All spun about. Down the broad steps of the Temple came flying a familiar figure. It was Prince Huaca. Behind him was Cinto, followed by a detachment of the Palace Guard. The soldiers were armed only with sword and lance. Whence, then, came the shots?

That was apparent the next instant. For, pausing in his flight, as with one great bound he reached the bottom of the steps, Prince Huaca faced about, leveled his arm, and fired.

"The automatic," cried Mr. Hampton. "I forgot I had given him one."

Cinto stumbled and fell in a crumpled heap on the steps.

CHAPTER XXVI--THE MOUNTAIN SPEAKS

"Come on, Dad," cried Jack. "Come on, fellows. Let's join him. We're in a bad hole here."

So astounded was the crowd about them by this new development, that, for the moment, it had forgotten the fainting of the Inca, forgotten the strangers. It was their chance. Whipping out their automatics, the eight, close together, burst through the fringe about them on the edge of the terrace and darted down the steps.

"Run, Prince," cried Mr. Hampton, in Spanish. "Run for the fortress. We are your friends. We follow."

Prince Huaca heard, glanced their way, and then stood stock-still in amazement. He had known nothing of their presence. But sufficient that they were at hand and were coming to his rescue. A smile of joy broke forth on his face. Instead of starting directly across the square, he dashed along the face of the steps of the Temple toward them.

Tumultuous cries broke out behind them now, and Bob and Jack, who brought up the rear, facing about, saw the mob of courtiers and soldiers, intermingled, start down the steps after them. One man was ahead of the others. He was Captain Guascar. Sword uplifted, unhindered by heavy armor as were his warriors, he came bounding down, three steps at a time.

"I don't like his looks, anyway," Bob cried to Jack. "Here's where I spoil 'em."

And, turning suddenly, the big fellow leaped back up the steps, dashed in under Guascar's up-raised sword, seized him about the waist, and with one mighty heave tossed his body into the face of the oncoming horde.

The flying form crashed into an armor-clad soldier and the two fell to the steps, bringing down still others who stumbled over them, unable to turn aside. In a trice the ma.s.s piled up.

"Run Bob, run," cried Jack, who had paused and turned back a step or two, revolver raised, to help his comrade with a shot, if necessary.

Big Bob grinned, leaped back to Jack's side, and the two raced down the steps.

This temporary diversion created by Bob's unexpected attack had given the others a good start. Their figures were out on the great square, darting for the distant fortress. Prince Huaca had joined them. The fall of the High Priest Cinto, shot down so unexpectedly by the prince, likewise had delayed pursuit from the Temple, as the soldiers had paused uncertainly, mystified as to this new form of death wielded by the prince.

Mr. Hampton at first had not noticed the absence of his son and Bob, being interested in speeding on the others and in sweeping the prince into their party. But as they started across the square, he looked back to a.s.sure himself the boys were following. He was just in time to see Bob's mighty heave, and the ruin which it wrought.

"Go on," he cried to the others. "We'll follow."

And he waited for the approach of the two lads.