CHAPTER XVII.

IN THE SHADOW OF THE CLIFFS.

For a moment Merriwell sat dazed and bewildered. It was true, then! Those few muttered words, overheard by chance the night before in the dining room of the Brown Palace, were true, and not wild figments of the imagination as he had supposed them. Somehow it did not occur to him for an instant to doubt Scott Randolph. Perhaps, had he not heard that stifled scrap of conversation, he might not have believed so readily this amazing, incredible statement. But it seemed to fit in so well with what Randolph had just told him--to confirm it, in a way--that he felt no doubt.

“Then what they said is true,” he murmured, his eyes fixed in wonder on the face of the slim man beside him.

Randolph suddenly stiffened as though an electric current had passed through his body.

“Who said?” he rasped. “What did they say? Quick, tell me!”

Dick repeated the scrap of conversation he and Brad had heard in the hotel dining room, and as he listened Randolph’s face paled.

“Who were they?” he asked in a strained voice, “What did they look like?”

Dick shook his head.

“I don’t know who they were. One was a medium-sized Jew, very carefully dressed; the other a stout man with a fat face and small blue eyes. The expression on his face was like that of a peevish baby. They both looked like men of importance.”

“Marcus Meyer!” Randolph exclaimed, with a sigh of relief. “I don’t know the other one, but Meyer controls the diamond trade in the Middle West. They don’t really know; they only guess. But even if they were sure, they would keep it quiet for their own sakes.”

Buckhart strolled toward them at that moment.

“You folks must have Frank talked to death,” he drawled.

“We’ve just finished,” the older man said, with a smile, as he rose from the couch. “Would you boys like to look about upstairs?”

In one breath the Yale men expressed their readiness, following their host out into the hall and up the broad stairs. Randolph touched a button at the top of the flight which flooded the upper hall with light. The next instant Dick thought he heard him draw a sudden, quick breath. Buckhart heard nothing, for he had dived promptly into an open door close to the head of the stairs.

“Any light in here?” he called.

Scott Randolph hesitated for the fraction of a second and then pressed a button on the wall.

“By George!” the Texan exclaimed. “This is sure a funny room. What’s it for, anyhow?”

Stepping to the door, Dick looked in. The room was a small one, not more than twelve feet square, and had neither doors nor windows, nor any other opening save the entrance. It was absolutely bare of furnishings, with not even a shelf on the wall nor a scrap of paper on the floor. There was nothing but the four walls of gray stone.

“Looks like a vault,” Buckhart remarked.

“It does, doesn’t it?” Randolph said slowly. “But the only treasures I have kept there are expensive chemicals which cannot be exposed to light or air or dampness. If I should shut this door on you, I venture to say that in two hours at the latest, you would have exhausted every bit of oxygen in the place; and since it is absolutely air tight----”

“Say, don’t!” the Westerner exclaimed, with an expression of mock dismay. “Let me amble out, quick!”

Scott Randolph laughed as Buckhart came out of the room, but his eyes narrowed a little when the Texan caught sight of the peculiar construction of the door. Instead of being of wood, it was of sheet steel. On one side were cemented slabs of stone so that, when closed, it would be absolutely impossible for a person inside to locate that door. On the outer side it was covered with the same oak paneling with which the hall was lined, and there were no signs of lock or catch, not even so much as a doorknob or latch.

“That’s certain sure a neat job,” Brad commented. “When it’s shut nobody can tell where it is. Regular secret room, isn’t it?”

“That was one of my hobbies,” the man of mystery explained. “When it is shut, I can push a secret spring which slides a powerful bolt and holds the door so that it would be easier to tear down the wall than to open it.”

He switched off the light and closed the door. Both Dick and Brad examined the wall closely, but neither of them could tell between which panels the joint came.

The remainder of the second floor was divided up into five bedrooms and a bathroom, the water for which was pumped into a tank on the roof by a windmill on the cliff above. Passing by a door at the end of the hall, which, as their host mentioned casually, opened into a store closet, they mounted to the next floor, which was given over entirely to the laboratory and experimenting rooms.

They were all filled with a multitude of machines and pieces of apparatus, many being of strange shapes and unknown uses. Randolph stepped forward to explain one of these to the Texan, giving Dick a significant glance, and at the same moment pulling open a drawer in a cabinet which stood against the wall.

Merriwell had difficulty in restraining an exclamation of amazement, for the drawer was half full of the most beautiful diamonds he had ever seen. They were of varying sizes from a pea to a small hickory nut, and Dick gave a stifled gasp as he looked at the shimmering, glittering blaze of light.

The man closed the drawer with a snap and turned to the visitors, his face a trifle pale. The drawer contained a king’s ransom. It seemed beyond the bounds of reason that they could have been actually manufactured by this slim, quiet man.

“But how do you get away from this place without anybody seeing you?” the Texan was asking. “People say you’re away for weeks at a time, but no one sees you go or come.”

Scott Randolph threw back his head and laughed heartily.

“That’s very simple,” he said. “I don’t go away. When a passion for work comes over me I shut myself up and absolutely refuse to open the door to any one. It’s the only way I can accomplish anything. They may hammer and pound all they like, but I pay no attention to it. That’s one of the reasons why I had this house built like a fortified castle. I can shut myself up in it and work undisturbed.

“Of course, I have to lay in a big supply of eatables, and so forth. For instance, this very afternoon I got in a big order from Jake Pettigrew’s store; and, when you have gone to-night and the door is locked behind you, I shall begin one of these periods of retirement in order to complete some very important work. Nothing short of blowing the house down would induce me to open the door again.”

As he finished he cast a significant glance at Dick, who thought he understood what that important work would be.

After looking about a little longer, they descended to the lower hall.

Glancing at his watch, Dick saw that it was almost ten o’clock.

“It’s about time we were wandering,” he said. “I can’t tell you how much I have enjoyed myself, Mr. Randolph. It is very good of you to have us up here, and I shall be careful in delivering your message to Frank.”

“The pleasure has been mine, I assure you,” Randolph returned, as he shook hands with the Yale men. “It is not often that I have such a relaxation. I am only sorry that the pressure of work will not allow me to see you again. However, we shall meet somewhere, some time. The world is very small, after all. Good-by, fellows, and good luck.”

As he spoke, he swung open the great steel door, and, with a cordial good-by, Merriwell and Buckhart went out into the night. For a brief instant they stood in the brilliant square of light which poured out of the doorway. Then it was suddenly blotted out as the door clanged and the bolt was shot.

“He’s sure not running any chances,” Buckhart remarked, as they stumbled forward through the darkness. “I reckon his work must be mighty important when he has to shut himself up in a prison to do it.”

Dick made no answer. He could scarcely say anything on that score without committing himself, so they felt their way along in silence until they struck the road. Their eyes becoming accustomed to the darkness, they made much better time to Bonnet Trail, where they found the _Wizard_ safe and sound as they had left her.

Merriwell turned on the prestolite and lit the lamps, before cranking her. Then, circling around, he started slowly down the road toward the city.

As they passed Pettigrew’s store a voice suddenly hailed them from the dark piazza:

“Hey, there, you fellows!”

Dick stopped the car and looked back.

“You want us?” he asked.

Pettigrew’s lank figure loomed up out of the darkness as he hurried to the side of the _Wizard_. His lively curiosity had made it impossible for him to sleep, and he had been sitting alone on the piazza for some time waiting for the return of the Yale men.

“I jest wondered how you made out up to The Folly?” he remarked, with an attempt at casualness.

Dick laughed.

“Why, we had a very good dinner and passed a pleasant evening there,” he replied.

“Waal, I swan!” ejaculated the storekeeper. “I reckon you’re the only fellers, ’ceptin’ Al Johnson, as is ever been inside the place. What’s it look like? What’d you have fur supper?”

“It’s just like any other house inside,” the Yale man answered. “You ought to know what we had for supper, you furnished the supplies, didn’t you?”

“I did not!” snapped Pettigrew. “I of’en wondered why this here Randolph don’t git his stuff here. It’s nearer nor anywhere else.”

Dick hesitated a moment.

“Didn’t Mr. Randolph leave a big order with you this afternoon?” he asked.

“No, nor any other arternoon,” the storekeeper returned promptly. “He never bought a cent’s worth offen me.”

This was evidently a sore point, for the man displayed considerable heat.

“Well, we must be getting on,” Dick said, as he let in his clutch. “Good night, Mr. Pettigrew.”

As the car glided away, Merriwell was thinking over this new discovery. Randolph had certainly told them of getting in a large order of supplies from Pettigrew’s that afternoon, and yet the storekeeper had just declared most emphatically that the man had never bought a cent’s worth from him. Randolph must have been lying. Why had he done so? What possible reason could he have for wishing to deceive them?

The next instant he put his hand up quickly to his breast pocket.

“By Jove, what a chump I am!” he exclaimed in a tone of annoyance.

“What’s the matter now, pard?” the Texan inquired.

Dick stopped the car with a jerk.

“I’ve left my pocketbook back at Randolph’s,” he explained.

“Are you sure you left it there?” Brad asked. “Mebbe you dropped it in the car.”

“No; I left it in the library,” Merriwell returned positively. “I remember now taking it out to get Frank’s letter, which Randolph wanted to read. I laid it on the couch, intending to replace the letter when he had finished. Instead, I must have put it in my pocket and left the bill case lying there. We’ll have to go back. It contains all my money and a lot of other things.”

He jammed on the reverse and, by dint of careful manœuvring, turned the car around and started back. In a few minutes the path was reached, and they scrambled out and hurried along it as rapidly as they could.

Under the bright starlight they had no trouble in finding their way; but reaching the plateau and facing the grim, stone building, it seemed even more desolate and deserted than when they had left it half an hour before. Under the shadow of the towering cliffs, the house loomed up a vague, mysterious bulk.

It did not seem possible that there could be a living soul behind those dark, silent walls; but it had looked that way before, and the opening door had revealed a bright glow of cheerful comfort. Consequently the two hastened confidently to the entrance and Dick knocked loudly on the steel door.

The sound reverberated in a hollow manner which seemed loud enough to wake the dead, and they waited expectantly for a response. But none came. Their keen ears could detect no sound of footsteps within; the massive door remained closed.

After five minutes of patient waiting, Dick was raising his hand to knock again when Buckhart gave a sudden exclamation.

“By George, pard! I’ll bet we can knock here all night without his coming. Don’t you remember what he said about shutting himself in after we were gone, and paying no attention to anybody or anything?”

“Yes, I remember that, all right,” Dick answered; “but I thought that, coming so soon after our departure, he would guess who it was and come down to----”

He broke off abruptly and looked swiftly upward.

“Listen!” he exclaimed in a low voice.

In the silence which followed there came faintly to their straining ears an odd, muffled humming. For a moment they both thought it was one of the pieces of machinery in Randolph’s laboratory, but very soon they reached the conclusion that it was much farther away than that. It seemed to come, in fact, from high up among the cliffs which towered above the house.

Dick looked at his friend significantly.

“It’s a gasoline engine,” he whispered.

Buckhart nodded silently. It certainly sounded very much like one.

“What the mischief is it doing up there on the mountain?” he asked presently.

There was no chance for Merriwell to reply. The humming increased as though the engine was speeding up, followed by a strange rustling, creaking noise unlike anything they had ever heard. Suddenly before their astonished eyes, a vast, black, shadowy shape rose slowly from the cliffs and hovered an instant in the air high above them. There was a majestic sweep of great wings, as it made a wide, half circle; then it shot northward into the darkness, gathering momentum at every instant, and a moment later the muffled hum of the engine died away in the distance.

“Thundering coyotes! What was that?” the Texan exclaimed, when he had recovered from his surprise.

“An aëroplane, I should say,” Dick returned quietly, though his voice quivered with suppressed excitement.

This new development added tremendously to the mystery with which the personality of Scott Randolph was surrounded, for it must belong to him. There could be no question of that. But why had he not spoken of it? What was it doing up on the cliffs? Above all, what did this silent, stealthy flight through the darkness mean?

“What in time is it doing up there?” Brad questioned.

“I haven’t an idea. I suppose it belongs to Randolph and that he keeps it up on the cliffs somewhere.”

Silently they turned and began to retrace their steps.

“Say, partner, mebbe that’s what he’s experimenting on,” the Texan remarked presently.

“Perhaps it is,” Dick returned absently.

Could it be that Randolph had deceived him? Was it possible that the amazing statement he had made was false, and that, instead of making diamonds, he was experimenting on an aëroplane?

Merriwell did not like to think that the man who had once been a friend to Frank, and whom he himself had found so attractive and likable, would stoop to a thing like that. It was so totally unnecessary, too. He need not have told any story at all had he desired to keep his work a secret. Dick had nailed one lie that night, and if there was one thing he despised above another it was a deliberate liar.

But there was the drawer full of diamonds. They were real enough and bore out the man’s astounding statement. It was a most puzzling situation.

All at once Buckhart caught his friend’s arm.

“Look,” he cried excitedly--“look at the lights!”

Following the direction of the Texan’s hand, Dick strained his eyes to the northward. There certainly were lights there. Brilliant, regular flashes came from high up in the air many miles away. As Merriwell studied them, it seemed to him that some one was signaling from the clouds. If they were really signals, the man was using a secret code and not the regular government system, with which Dick was perfectly familiar. Suddenly they ceased.

“Signals, weren’t they?” Buckhart inquired.

“Looked like it; but I don’t know the code.”

They had reached the car and Dick stooped to crank it. The next instant he let go the handle and stood erect, his head bent back and his eyes upward, in an attitude of strained attention.

A faint humming sound came from the distance, gradually growing louder.

The aëroplane was returning.

Even as this conviction darted into his mind, the vast shape flashed by high in the air. For a second the shadowy form was barely discernible against the glittering stars, and then it vanished from sight among the mountains.

“Back again, eh?” commented the Texan. “What do you know about that? I tell you, pard, this here gent has sure got me guessing some.”

Starting the engine with a flip of the crank, Dick took his seat at the wheel and Buckhart climbed in beside him.

“You’re not the only one he has guessing,” Merriwell remarked, after he had turned the car and started back. “He’s a most perplexing mystery, and I rather think we couldn’t spend to-morrow more profitably than in trying to solve that problem.”

For several hours that night Dick tossed restlessly on the bed. His mind was working so actively that it seemed impossible to go to sleep. Theory after theory flashed into his brain, as he sought to account for the curious behavior of Scott Randolph, only to be rejected because of some serious flaw in his reasoning. Each of the important, vital facts he had gathered concerning this mysterious man were utterly at variance with the other.

The astounding statement that he had discovered a method of manufacturing diamonds seemed to be corroborated by the drawer full of the precious gems, and also by the scrap of conversation the two Yale men had overheard in the dining room of the Brown Palace. Besides, Dick knew that diamonds had been produced by scientists, though not on a scale which made the process a scientific success. But the thing was possible.

In the face of all this stood the lie Randolph had told and the presence of the aëroplane. Why had the man kept such absolute silence about the flying machine when he had been so communicative in a far more vital matter? And more than that, why had he told Dick a deliberate falsehood in the matter of the provisions? What had been his object? What had he gained?

At last the Yale man gave it up and fell into a troubled slumber.

Bright and early next morning the _Wizard_ again left the city and spun out along Bonnet Trail. Merriwell had cashed a check at the desk before starting and so was supplied with funds. Yet he was anxious to obtain his bill case more for the papers it contained than for anything else; and besides, it would serve him as a sufficient excuse for trying to locate Randolph.

Again the car was driven over to the side of the trail and the coil plug removed. Again the two friends hurried up the narrow, mountain track which led to the mysterious house of stone.

In the bright glare of the morning sun it did not look so gloomy and desolate as it had the night before; but it was still quite grim and forbidding enough, with its blank expressionless windows and absolute lack of sound or life.

Merriwell had hardly expected any response to his repeated poundings on the metal door, and he was not disappointed. He might have spared himself the effort.

When he was finally satisfied that there was no possibility of effecting an entrance, he turned his attention to the cliffs above the house, from which the aëroplane had appeared. A glance told him that they were insurmountable. For the greater part of their height they were almost as smooth as glass, and the top ledges overhung the plateau in such a manner as to make an attempt at climbing them out of the question.

“I’d certainly like to get up there,” he remarked. “But there’s nothing doing from here.”

“Do you think the flying machine is up there, pard?” Buckhart inquired.

“That’s what I want to find out,” Merriwell returned, “I shouldn’t be surprised if it were.”

He stepped to the edge of the ravine from which Randolph had appeared the afternoon previous, but though a faint outline of a path showed among the rocks, it turned abruptly away from the cliffs and followed the course of a little stream as far as the eye could reach.

“Let’s take the car and go up the trail a bit,” Dick said, as he turned from the ravine. “Perhaps we can find some way to climb up the mountains in that direction.”

They went back to the car and Dick drove slowly on along Bonnet Trail. For perhaps a mile nothing favorable appeared, then his quick eye discerned the almost obliterated signs of where a path had once wound among the rocks up the steep slope. Drawing the car in to the side of the road, they stepped out and started their climb.

The path was rough and winding. Once or twice they lost it, but, after a little searching, struck it again farther up. The general direction it took was southeast, and Dick noticed with satisfaction that it seemed to lead with more or less directness, toward the heights surrounding the stone house. On the side of the mountains was a fair amount of vegetation--small pine trees and some underbrush. Presently, emerging upon a wide, fairly level spot surrounded by the higher reaches of mountain, they stopped stock-still in astonishment.

Quite near them was a small cabin, ruined and decayed. It had evidently been long deserted, and what its former use had been it was impossible to determine.

It was not upon the cabin, however, that their eyes were fixed in gaping amazement. It was a question whether they even saw it at first, so engrossed were they in the intricate mass of rods and metal, burnished copper and great, wide-spreading planes which lay on the ground near them, stretched out like an enormous, uncouth bird at rest.

“By George!” the Texan exclaimed. “It’s the flying machine, or I’ll eat my hat!”

“It certainly looks like it,” Dick returned with much satisfaction.

Then a strange voice sounded from the cabin, and the two Yale men whirled around instantly in surprise.

“Guessed right the first crack, gents. It sure is a flying machine.”