n a secluded spot among the hills of northern New Jersey stood the old DeBost mansion, a rambling frame structure of many wings and gables that was well-nigh hidden from the road by the half-mile or more of second-growth timber which intervened. High on the hill it stood, and it was only by virtue of its altitude that an occasional glimpse might be obtained of weatherbeaten gable or partly tumbled-down chimney. The place was reputed to be haunted since the death of old DeBost, some seven years previously, and the path which had once been a winding driveway was now seldom trod by human foot.

It was now two years since Edwin Leland bought the estate for a song and took up his residence in the gloomy old house. And it had then been vacant for five years since DeBost shot himself in the northeast bedroom. Leland's associates were sure he would repent of his bargain in a very short time, but he stayed on and on in the place, with no company save that of his man-servant, an aged hunch-back who was known to outsiders only as Thomas.

Leland was a scientist of note before he buried himself in the DeBost place, and had been employed in the New York research laboratory of one of the large electrical manufacturers, where he was much admired and not a little envied by his fellow workers. These knew almost nothing of his habits or of his personal affairs, and were much surprised when he announced one day that he had come into a sizable fortune and was leaving the organization to go in for private research and study. Attempts to dissuade him were of no avail, and the purchase of the DeBost property followed, after which Leland dropped from sight for nearly two years.

hen, on a blustery winter day, a strange telephone call was received at the laboratory where he had previously worked. It was from old Thomas, out there in the DeBost mansion, and his quavering voice asked for Frank Rowley, the genial young engineer whose work had been most closely associated with Leland's.

"Oh, Mr. Rowley," wailed the old man, when Frank responded to the call, "I wish you would come out here right away. The master has been acting very queerly of late, and to-day he has locked himself in his laboratory and will not answer my knocks."

"Why don't you break in the door?" asked Frank, looking through the window at the snow storm that still raged.

"I thought of that, Mr. Rowley, but it is of oak and very thick. Besides, it is bound with steel or iron straps and is beyond my powers."

"Why not call the police?" growled Frank. He did not relish the idea of a sixty or seventy mile drive in the blizzard.

"Oh—no—no—no!" Old Thomas was panicky at the suggestion. "The master told me he'd kill me if I ever did that."

Before Frank could formulate a reply, there came a sharp gasp from the other end of the line, a wailing cry and a thud as of a falling body; then silence. All efforts to raise Leland's number merely resulted in "busy" or "line out of order" reports.

Frank Rowley was genuinely concerned. Though he had never been a close friend of Leland's, the two had worked on many a knotty problem together and were in daily contact during the nearly ten years that the other man had worked in the same laboratory.

"Say, Tommy," said Frank, replacing the receiver and turning to his friend, Arnold Thompson, who sat at an adjoining desk, "something has happened out at Leland's place in Sussex County. Want to take a drive out there with me?"

"What? On a day like this? Why not take the train?"

"Don't be foolish, Tommy," said Frank. "The place is eight miles from the nearest station, which is a flag stop out in the wilds. And, even if you could find a cab there—which you couldn't—there isn't a taxi driver in Jersey who'd take you up into those mountains on a day like this. No, we'll have to drive. It'll be okay. I've got chains on the rear and a heater in the old coupe, so it shouldn't be so bad. What do you say?"

So Tommy, who usually followed wherever Frank led, was prevailed upon to make the trip. He had no particular feeling for Leland, but he sensed an adventure, and, in Frank's company, he could ask for no more.

rank was a careful driver, and three hours were required to make the sixty-mile journey. Consequently, it was late in the afternoon when they arrived at the old DeBost estate. It had stopped snowing, but the drifts were deep in spots, and Frank soon found that the car could not be driven through the winding path from the road to the house. So they left it half buried in a drift and proceeded on foot.

It was a laborious task they had undertaken, and, by the time they set foot on the dilapidated porch, even Frank, husky and athletic as was his build, was puffing and snorting from his exertions. Little Tommy, who tipped the scales at less than a hundred and twenty, could hardly speak. They both were wet to the waist and in none too good humor.

"Holy smoke!" gasped Tommy, stamping the clinging snow from his sodden trouser legs and shoes, "if it snows any more, how in Sam Hill are we going to get out of this place?"

"Rotten trip I let you in for Tommy," growled Frank, "and I hope Leland's worth it. But, darn it all, I just had to come."

"It's all right with me, Frank. And maybe it'll be worth it yet. Look—the front door's open."

e pointed to the huge oaken door and Frank saw that it was ajar. The snow on the porch was not deep and they saw that footprints led from the open door to a corner of the porch. At that point the snow on the railing was disturbed, as if a hurrying man had clung to it a moment before jumping over and into the drifts below. But the tracks led no further, for the drifting snow had covered all excepting a hollow where some body had landed.

"Thomas!" exclaimed Frank. "And he was in a hustle, by the looks of the tracks. Bet he was frightened while at the telephone and beat it."

They entered the house and closed the door behind them. It was growing quite dark and Frank searched for the light switch. This was near the door, and, at pressure on the upper button, the spacious old hall with its open staircase was revealed dimly by the single remaining bulb in a cluster set in the center of the high ceiling. The hall was unfurnished, excepting for a telephone table and chair, the chair having fallen to the floor and the receiver of the telephone dangling from the edge of the table by its cord.

"You must have heard the chair fall," commented Tommy, "and it sure does look as if Thomas left in a hurry. Wonder what it was that frightened him?"

The house was eerily silent and the words echoed awesomely through the adjoining rooms which connected with the hall through large open doorways.

"Spooky place, isn't it?" returned Frank.

nd then they were both startled into immobility by a rumble that seemed to shake the foundations of the house. Heavier and heavier became this vibration, as if some large machine was coming up to speed. Louder and louder grew the rumble until it seemed that the rickety old house must be shaken down about their ears. Then there came a whistling scream from the depths of the earth—from far underground it seemed to be—and this mounted in pitch until their eardrums tingled. Then abruptly the sounds ceased, the vibration stopped, and once more there was the eery silence.

Rather white-faced, Tommy gazed at Frank.

"No wonder old Thomas beat it!" he said. "What on earth do you suppose that is?"

"Search me," replied Frank. "But whatever it is, I'll bet it has something to do with Leland's strange actions. And we're going to find out."

He had with him the large flashlamp from the car, and, by its light, the two made their way from room to room searching for the iron-bound door mentioned by Thomas.

They found all rooms on the first and second floors dusty and unused with the exception of two bedrooms, the kitchen and pantry, and the library. It was a gloomy and spooky old house. Floor boards creaked startlingly and unexpectedly and the sound of their footsteps echoed dismally.

"Where in time is that laboratory of Leland's?" exclaimed Frank, his ruddy features showing impatient annoyance, exaggerated to an appearance of ferocity by the light of the flashlamp.

"How about the cellar?" suggested Tommy.

"Probably where it is," agreed Frank, "but I don't relish this job so much. I'd hate to find Leland stiff down there, if that's where he is."

"Me, too," said Tommy. "But we're here now, so let's finish the job and get back home. It's cold here, too."

"You said it. No steam in the pipes at all. He must have let the fire go out in his furnace, and that's probably in the cellar too—usually is."

hile talking, Frank had opened each of the four doors that opened from the kitchen, and the fourth revealed a stairway that led into the blackness beneath. With the beam of his torch directed at the steps, he proceeded to descend, and Tommy followed carefully. There was no light button at the head of the stairs, where it would have been placed in a more modern house, and it was not until they had reached the furnace room that they located a light fixture with a pull cord. An ordinary cellar, with furnace, coal bin, and a conglomeration of dust-covered trunks and discarded furniture, was revealed. And, at its far end, was the iron-bound door.

The door was locked and could not be shaken by the combined efforts of the two men.

"Have to have a battering ram," grunted Frank, casting about for a suitable implement.

"Here you are," called Tommy, after a moment's search. "Just the thing we are looking for."

e had come upon a pile of logs, and one of these, evidently a section of an old telephone pole, was of some ten or twelve inches diameter and about fifteen feet long. Frank pounced upon it eagerly, and, supporting most of the weight himself, led the attack on the heavy oak door with the iron bands.

No sound from within greeted the thunderous poundings. Clearly, if Leland was behind that door, he was either dead or unconscious.

Finally the double lock gave way and Tommy and Frank were precipitated headlong into the brightly lighted room beyond. Recovering their balance, they took stock of their surroundings and were amazed at what they saw—a huge laboratory, fitted out with every modern appliance that money could buy. A completely equipped machine shop there was; bench after bench covered with the familiar paraphernalia of the chemical and physical laboratory; huge retorts and stills; complicated electrical equipments; dozens of cabinets holding crucibles, flasks, bottles, glass tubing, and what not.

"Good Lord!" gasped Tommy. "Here's a laboratory to more than match our own. Why, Leland's got a fortune invested here!"

"I should say so. And a lot of stuff that our company does not even have. Some of it I don't know even the use of. But where is Leland?"

here was no sign of the man they had come to help. He was not in the laboratory, though the door had been locked from within and the lights left burning throughout.

With painstaking care they searched every nook and cranny of the large single room and were about to give up in despair when Tommy happened to observe an ivory button set into the wall at the only point in the room where there were no machines or benches at hand. Experimentally he pressed the button, and, at the answering rumble from under his feet, jumped back in alarm. Slowly there opened in the paneled oak wall a rectangular door, a door of large enough size to admit a man. From the recess beyond there came a breath of air, foul with the musty odor of decayed vegetation, dank as the air of a tomb.

"Ah-h-h!" breathed Frank. "So that is where Ed Leland is hiding! The secret retreat of the gloomy scientist!"

He spoke half jestingly, yet when he squeezed his stalwart bulk through the opening and flashed the beam of his light into the darkness of a narrow passage ahead he was assailed with vague forebodings. Tommy followed close behind and spoke not a word.

he passage floor was thick with dust, but the marks of many footsteps going and returning gave mute evidence of the frequency of Leland's visits. The air was heavy and oppressive and the temperature and humidity increased as they progressed along the winding length of the rock-walled passageway. The floor sloped, ever downward and, in spots, was slippery with slimy seepage. It seemed that they turned back on their course on several occasions but were descending deeper and deeper into the heart of the mountain. Then, abruptly, the passage ended at the mouth of a shaft, which dropped vertically from almost beneath their feet.

"Whew!" exclaimed Frank. "Another step and I'd have dropped into it. That's probably what happened to Leland."

He knelt at the rim of the circular opening and looked into the depths of the pit, Tommy following suit. The feeble ray of the flashlight was lost in the blackness below.

"Say, Frank," whispered Tommy, "turn off the flash. I think I saw a light down there."

And, with the snapping of the catch, there came darkness. But, miles below them, it seemed, there was a tiny pin-point of brilliance—an eery green light that was like a wavering phosphorescence of will-o'-the-wisp. For a moment it shone and was gone. Then came the dreadful vibration they had experienced in the hall of the house—the whistling scream that grew louder and louder until it seemed they must be deafened. The penetrating wail rose from the depths of the pit, and the vibration was all around them, in the damp rock floor on which they knelt, and in the very air of the cavern. Hastily Frank snapped on the light of his flash.

"Oh boy!" he whispered. "Leland is certainly up to something down there and no mistake! How're we going to get down?"

"Get down?" asked Tommy. "You don't want to go down there, do you?"

"Sure thing. We're this far now and, by George, we're going to find out all there is to learn."

"How deep do you suppose it is?"

"Pretty deep, Tommy. But we can get an idea by dropping a stone and counting the seconds until it strikes."

e played the light of the flash over the floor and soon located a smooth round stone of the size of a baseball. This he tossed over the rim of the pit and awaited results.

"Good grief!" exclaimed Tommy. "It's not falling!"

What he said was true, for the stone poised lightly over the opening and drifted like a feather. Then slowly it moved, settling gradually into oblivion. Frank turned the flash downward and they watched in astonishment as the two-pound pebble floated deliberately down the center of the shaft at the rate of not more than one foot in each second.

"Well, I'll be doggoned," breathed Frank admiringly. "Leland has done it. He has conquered gravity. For, in that pit at least, there is no gravity, or at any rate not enough to mention. It has been almost completely counteracted by some force he has discovered and now we know how to follow him down there. Come on Tommy, let's go!"

And, suiting action to his words, Frank jumped into the mouth of the pit where he bobbed about for a moment as if he had jumped into a pool of water. Then slowly he sank from view, and Tommy followed him.

t was a most unique experience, that drop into the heart of the mountain. Practically weightless, the two young men found it quite difficult to negotiate the passage. For the first hundred or more feet they continued to bump about in the narrow shaft and each sustained painful bruises before he learned that the best and simplest method of accommodating himself to the strange condition was to remain absolutely motionless and allow the greatly weakened gravity to take its course. Each movement of an arm or leg was accompanied by a change in direction of movement, and contact with the hard stone walls followed. If they endeavored to push themselves from the contact the result was likely to be an even more serious bump on the opposite side of the shaft. So they continued the leisurely drop into the unknown depth of the pit.

Frank had turned off the flashlamp, for its battery was giving out and he wished to conserve its remaining energy for eventualities. Thus they were in Stygian darkness for nearly a half-hour, though the green luminosity far beneath them grew stronger with each passing minute. It now revealed itself as a clearly defined disc of light that flickered and sputtered continually, frequently lighting the lower end of the shaft with an unusual burst of brilliance. Remotely distant it seemed though, and unconscionably slow in drawing nearer.

"How far do you think we must drop?" called Tommy to Frank, who was probably fifty feet below him in the shaft.

"Well, I figure we have fallen about a thousand feet so far," came the reply, "and my guess is that we are about one third of the way down."

"Then this shaft is over a half-mile deep, you think?"

"Yes, at least a thousand yards, I should say. And I hope his gravity neutralizing machinery doesn't quit all of a sudden and let us down."

"Me, too," called Tommy, who had not thought of that possibility.

his was no joke, this falling into an unknown region so far beneath the surface of good old mother earth, thought Tommy. And how they would ever return was another thing that was not so funny. Frank was always rushing into things like this without counting the possible cost and—well—this might be the last time.

Gradually the mysterious light became stronger and soon they could make out the conformation of the rock walls they were passing at such a snail's pace. Layers of vari-colored rock showed here and there, and, at one point there was a stratum of gold-bearing or mica-filled rock that glistened with a million reflections and re-reflections. The air grew warmer and more humid as they neared the mysterious light source. They moved steadily, without acceleration, and Frank estimated the rate at about forty feet a minute. Then, with blinding suddenness, the light was immediately below and they drifted into a tremendous cavern that was illuminated by its glow.

Directly beneath the lower end of the shaft through which they had passed, there was a glowing disc of metal about fifteen feet in diameter. They drifted to its surface and sprawled awkwardly where they fell. Scrambling to gain a footing, they bounced and floated about like toy balloons before realizing that it would be necessary to creep slowly from the influence of that repelling force which had made the long drop possible without injury. Gravity met them at the disc's edge with what seemed to be unusual violence.

t first it seemed that their bodies weighed twice the normal amount, but this feeling soon passed and they looked about them with incredulous amazement. The metal disc was quite evidently the medium through which the repelling force was set up in the shaft, and to this disc was connected a series of heavy cables that led to a pedestal nearby. On the pedestal was a controlling lever and this moved over a quadrant that was graduated in degrees, one end of the quadrant being labeled "Up" and the other "Down." The lever now stood at a point but a very few degrees from the center or "Zero" mark and on the down side. Frank pulled this lever over to the full "Down" position and they found that they could walk over the disc with normal gravity.

"I suppose," said Frank, "that if the lever is at the other end of the scale one would fall upward with full gravity acceleration—reversed. At zero, gravity is exactly neutralized, and the intermediate positions are useful in conveying materials or human beings up and down the shaft as desired. Very clever; but what is the reason for it all?"

In the precise center of the great cavern there was a dome or hemisphere of polished metal, and it was from this dome that the eery light emanated. At times, when the light died down, this dome gleamed with dull flickerings that threatened to vanish entirely. Then suddenly it would resume full brilliance, and the sight was marvelous beyond description. A slight hissing sound came from the direction of the dome, and this varied in intensity as did the light.

"Gosh!" said Tommy. "That looks like silver to me. And, if it is, what a wealthy man our friend Leland has become. He has spent his fortune well, even if he used it all to get to this."

"Yes, but where is he?" commented Frank. Then: "Leland! Leland!" he called.

is voice echoed through the huge vault and re-echoed hollowly. But there was no reply save renewed flickerings from the dome.

Leaving the vicinity of the gravity disc, the two men advanced in the direction of the shining dome, which was about a quarter-mile from where they stood. Both perspired freely, for the air was very close and the temperature high. But the light of the dome was as cold as the light of a firefly and they had no hesitancy in drawing near. It was a beautiful sight, this dome of silver with its flickering lights and perfect contour.

"By George, I believe it is silver," exclaimed Frank, when they were within a few feet of the dome. "No other metal has that precise color. And look! There is a wheelbarrow and some mining tools. Leland has been cutting away some of the material."

Sure enough, there was indisputable evidence of the truth of his statement. And the material was undoubtedly silver!

"Silver Dome," breathed Tommy, holding a lump of the metal in his hand. "A solid dome of pure silver—fifty feet high and a hundred in diameter. How much does that figure in dollars and cents, Frank?"

"Maybe it isn't solid," said Frank dryly, "though it's worth a sizeable fortune even if it is hollow. And we haven't found Leland."

hey circled the dome twice and looked into every corner of the great cavern, but there was no sign of the man for whom they searched. The wheelbarrow was half filled with lumps of the heavy metal, and maul and drill lay where they had been dropped by the lone miner. A cavity three feet across, and as many deep, appeared in the side of the dome to show that considerably more than one wheelbarrow load had been removed.

"Funny," grunted Tommy. "Seems almost like the old dome had swallowed him up."

At his words there came the terrific vibration. The light of the dome died out, leaving them in utter darkness, and from its interior there rose the mounting scream that had frightened old Thomas away. From so close by it was hideous, devastating; and the two men clung to each other in fright, expecting momentarily that the earth would give way beneath their feet and precipitate them into some terrible depth from which there could be no return.

Then the sound abruptly ceased and a gleam of light came from under the dome of silver. A crack appeared between its lower edge and the rocky floor of the cavern, and through this crack there shone a light of dazzling brilliancy—a warm light of rosy hue. Wider grew the opening until there was a full three feet between the floor and the bottom of the dome. Impelled by some irresistible force from within, the two men stumbled blindly to the opening, fell to the floor and rolled inside.

There was a heavy thud and the dome had returned to its normal position, with Frank and Tommy prisoners within its spacious hollow. The warm light bathed them with fearful intensity for a moment, then faded to a rosy glow that dulled their senses and quieted their nerves. Morpheus claimed them.

hen Frank awoke he found himself between silken covers, and for a moment he gazed thoughtfully at a high arched ceiling that was entirely unfamiliar. Then, remembering, he sprang from the downy bed to his feet. The room, the furnishings, his silken robe, everything was strange. His bed, he saw, was a high one, and the frame was of the same gleaming silver as the dome under which they had been trapped. The arched ceiling glowed softly with the same rosy hue as had the inner surface of the dome. A large pool of water invited him, the surface of the pool being no more than a foot below the point where it was built into the tile floor of the room. A large open doorway connected with a similar adjoining room, where he suspected Tommy had been taken. On his bare toes, he moved silently to the other room and saw that his guess had been correct. Tommy lay sleeping quietly beneath covers as soft as his own and amidst equal luxury of surroundings.

"Well," he whispered, "this doesn't look as though we would come to any harm. And I might as well take a dive in that pool."

Returning to his own room, he removed the silken garment with which he had been provided and was quietly immersed in the cool, invigorating water of the bath. His head cleared instantly.

"Hi there!" called Tommy from the doorway. "Why didn't you wake me up? Where are we, anyway?"

With dripping head and shoulders above the water, Frank was compelled to laugh at the sleepy-eyed, wondering expression on the blue-jowled face of his friend. "Thought you were dead to the world," he returned, "you old sleepy-head. And I don't know where we are, excepting that it is somewhere under the silver dome. What's more, I don't much care. You should get into this water. It's great!"

o saying, he dived to the bottom of the pool and stood on his hands, his feet waving ludicrously above the surface. Tommy sniffed once and then made a quick dash for the pool in his own room. He was not to be outdone by his more energetic partner.

A half-hour later, shaved and attired in their own garments, which had been cleaned and pressed and hung neatly in the closets, they settled themselves for a discussion of the situation. Having tried the doors of both rooms and found them locked from the outside, there was no other course open to them. They must await developments.

"Looks like Leland has quite an establishment down here inside the mountain," ventured Tommy.

"Hm!" snorted Frank, "this place is none of Leland's work. He is probably a prisoner here, as are we. He just stumbled on to the silver dome and was captured by whatever race is living down here beneath it, the same as we were. Who the real inhabitants are, and what the purpose of all this is, remains to be seen."

"You think we are in friendly hands?"

"These quarters do not look much like prison cells, Tommy, but I must admit that we are locked in. Anyhow, I'm not worrying, and we will soon learn our fate and have to be ready to meet it. The people who own this place must have everything they want, and they sure have some scientific knowledge that is not known to us on the surface."

"Wonder if they are humans?"

"Certainly they are. You never heard of wild beasts sleeping in beds like these, did you?"

ommy laughed at he examined the exquisite hand-wrought figures on the silver bedstead. "No, I didn't," he admitted; "but where on earth did they come from, and what are they doing here?"

"You ask too many questions," replied Frank, shrugging his broad shoulders. "We must simply wait for the answers to reveal themselves."

There was a soft rap at the door of Frank's room, where the two men were talking.

"Come in," called Frank, chuckling at the idea of such consideration from their captors.

A key rattled in the lock and the door swung open to admit the handsomest man they had ever set eyes on. He was taller than Frank by several inches, standing no less than six feet five in his thin-soled sandals, and he carried himself with the air for an emperor. His marble-white body was uncovered with the exception of a loin cloth of silver hue, and lithe muscles rippled beneath his smooth skin as he advanced to meet the prisoners. His head, surmounted by curly hair of ebon darkness, was large, and his forehead high. The features were classic and perfectly regular. The corners of his mouth drew upward in a benign smile.

"Greetings," he said, in perfect English and in a soft voice, "to the domain of Theros. You need fear no harm from our people and will be returned to the upper world when the time comes. We hope to make your stay with us enjoyable and instructive, and that you will carry back kind memories of us. The morning meal awaits you now."

o taken aback were the two young Americans that they stared foolishly agape for a space. Then a tinkling laugh from the tall stranger set them once more at ease.

"You will pardon us, I hope," apologized Frank, "but this is all so unexpected and so unbelievable that your words struck me speechless. And I know that my friend was similarly affected—We place ourselves in your hands."

The handsome giant nodded understanding. "No offense was taken," he murmured, "since none was intended. And your feelings are not to be wondered at. You may call me Orrin."

He turned toward the open door and signified that they were to follow him. They fell in at his side with alacrity, both suddenly realizing that they were very hungry.

They followed in silent wonderment as Orrin led the way to a broad balcony that overlooked a great underground city—a city lighted by the soft glow from some vast lighting system incorporated in its vaulted ceiling high overhead. The balcony was many levels above the streets, which were alive with active beings of similar appearance to Orrin, these speeding hither and yon by means of the many lanes of traveling ways of which the streets were composed. The buildings—endless rows of them lining the orderly streets—were octagonal in shape and rose to the height of about twenty stories, as nearly as could be judged by earthly standards. There were no windows, but at about every fifth floor there was an outer silver-railed balcony similar to the one on which they walked. The air was filled with bowl-shaped flying ships that sped over the roof tops in endless procession and without visible means of support or propulsion. Yet the general effect of the busy scene was one of precise orderliness, unmarred by confusion or distracting noises.

rrin vouchsafed no explanations and they soon reentered the large building of which the balcony was a part. Here they were conducted to a sumptuously furnished dining room where their breakfast awaited them.

During the meal, which consisted of several courses of fruits and cereals entirely strange to Frank and Tommy, they were tended by Orrin with the utmost deference and most painstaking attention. He anticipated their every want and their thoughts as well. For, when Frank endeavored to ask one of the many questions with which his mind was filled, he was interrupted by a wave of the hand and a smile from their placid host.

"It is quite clear to me that you have many questions to propound," said Orrin, "and this is not a matter of wonder. But it is not permitted that I enlighten you on the points you have in mind. You must first finish your meal. Then it is to be my privilege to conduct you to the presence of Phaestra, Empress of Theros, who will reveal all. May I ask that you be patient until then?"

So friendly was his smile and so polished his manner that they restrained their impatience and finished the excellent breakfast in polite silence.

And Orrin was as good as his word, for, no sooner had they finished when he led them from the room and showed the way to the elevator which conveyed them to the upper floor of the building.

From the silver-grilled cage of the lift they stepped into a room of such beauty and magnificence of decoration that they gazed about them in wondering admiration. The paneling and mouldings were of hammered silver that gleamed with polished splendor in the soft rose glow of the hidden lights. The hangings were of heavy plush of deep green hue and bore intricate designs of silver thread woven into the material. At the opposite side of the room there was a pair of huge double doors of chased silver and on either side of this pretentious portal there stood an attendant attired as was Orrin, but bearing a silver scepter to denote his official capacity.

"Phaestra awaits the visitors from above," intoned one of the attendants. Both bowed stiffly from the waist when Orrin led the two young scientists through the great doors which had opened silently and majestically at their approach.

f the outer room was astonishing in its sumptuousness of decoration and furnishing, the one they now entered was positively breath-taking. On every side there were the exquisite green and silver hangings. Tables, divans, and rugs of priceless design and workmanship. But the beauty of the surroundings faded into insignificance when they saw the empress.

A canopied dais in the center of the room drew their attention and they saw that Phaestra had risen from her seat in a deeply cushioned divan and now stood at its side in an attitude of welcome. Nearly as tall as Frank, she was a figure of commanding and imperious beauty. The whiteness of her body was accentuated by the silver embroidered and tightly fitted black vestments that covered yet did not conceal its charms. A halo of glorious golden hair surmounted a head that was poised expectantly alert above the perfectly rounded shoulders. The exquisite oval of her face was chiseled in features of transcendent loveliness. She spoke, and, at sound of her musical voice, Frank and Tommy were enslaved.

entlemen of the upper world," she said gently, "you are welcome to Theros. Your innermost thoughts have been recorded by our scientists and found good. With a definite purpose in mind, you learned of the existence of the silver dome of Theros, yet you came without greed or malice and we have taken you in to enlighten you on the many questions that are in your minds and to return you to mankind with a knowledge of Theros—which you must keep secret. You are about to delve into a mystery of the ages; to see and learn many things that are beyond the ken of your kind. It is a privilege never before accorded to beings from above."

"We thank you, oh, Queen," spoke Frank humbly, his eyes rivetted to the gaze of those violet orbs that seemed to see into his very soul. Tommy mumbled some commonplace.

"Orrin—the sphere!" Phaestra, slightly embarrassed by Frank's stare, clapped her hands.

At her command, Orrin, who had stood quietly by, stepped to the wall and manipulated some mechanism that was hidden by the hangings. There was a musical purr from beneath the floor, and, through a circular opening which appeared as if by magic, there rose a crystal sphere of some four feet in diameter. Slowly it rose until it reached the level of their eyes and there it came to rest. The empress raised her hands as if in invocation and the soft glow of the lights died down, leaving them in momentary darkness. There came a slight murmur from the sphere, and it lighted with the eery green flickerings they had observed in the dome of silver.

ascinated by the weaving lights within, they gazed into the depths of the crystal with awed expectancy. Phaestra spoke.

"Men from the surface," she said, "you, Frank Rowley, and you, Arnold Thompson, are about to witness the powers of that hemisphere of metal you were pleased to term 'Silver Dome.' As you rightly surmised, the dome is of silver—mostly. There are small percentages of platinum, iridium, and other elements, but it is more than nine-tenths pure silver. To you of the surface the alloy is highly valuable for its intrinsic worth by your own standards, but to us the value of the dome lies in its function in revealing to us the past and present events of our universe. The dome is the 'eye' of a complicated apparatus which enables us to see and hear any desired happening on the surface of the earth, beneath its surface, or on the many inhabited planets of the heavens. This is accomplished by means of extremely complex vibrations radiated from the hemisphere, these vibrations penetrating earth, metals, buildings, space itself, and returning to our viewing and sound reproducing spheres to reveal the desired past or present occurrences at the point at which the rays of vibrations are directed.

n order to view the past on our own planet, the rays, which travel at the speed of light, are sent out in a huge circle through space, returning to earth after having spent the requisite number of years in transit. Instantaneous effect is secured by a connecting beam that ties together the ends of the enormous arc. This, of course, is beyond your comprehension, since the Ninth Dimension is involved. When it is desired that events of the present be observed, the rays are projected direct. The future can not be viewed, since, in order to accomplish this, it would be necessary that the rays travel at a speed greater than that of light, which is manifestly impossible."

"Great guns!" gasped Frank. "This crystal sphere then, is capable of bringing to our eyes and ears the happenings of centuries past?"

"It is, my dear Frank," said Phaestra, "and I would that I were able to describe the process more clearly." She smiled, and in the unearthly light of the sphere she appeared more beautiful than before, if such a thing were possible.

On the pedestal which supported the sphere there was a glittering array of dials and levers. Several of these controls were now adjusted by Phaestra, the delicate motions of her tapered fingers being watched by the visitors with intense admiration. There came a change in the note of the sphere, a steadying of the flickerings within.

"Behold!" exclaimed Phaestra.

hey gazed into the depths of the sphere and lost all sense of detachment from the scene depicted therein. It seemed they were at a point several thousand miles from the surface of a planet. A great continent spread beneath them, its irregular shore line being clearly outlined against a large body of water. Here and there the surface was obscured by great white patches of clouds that cast their shadows below.

"Atlantis!" breathed Phaestra reverently.

The lost continent of mythology! The fabled body of land that was engulfed by the Atlantic thousands of years ago—a fact!

Tommy glanced at Frank, noting that he had withdrawn his gaze from the sphere and was devouring Phaestra with his eyes. As if drawn by the ardor of his observation, she raised her own eyes from the sphere to meet those of the handsome visitor. Obviously confused, she dropped her long lashes and turned nervously to the controls. Tommy experienced a sudden feeling of dread. Surely his pal was not falling in love with this Theronian empress!

Then there came another change in the note of the sphere and once more they lost themselves in contemplation of the scene within. The surface of the lost continent was rushing madly to meet them. With terrific velocity they seemed to be falling. An involuntary gasp was forced from Tommy's lips. Mountains, valleys, rivers could now be discerned.

hen the scene shifted slightly and they were stationary, directly above a large seacoast city. A city of great beauty it was, and its buildings were of the same octagonal shape as were those of Theros! There could be but one inference—the Theronians were direct descendants of those inhabitants of ancient Atlantis.

"Yes," sighed Phaestra, in answer to the thought she had read, "our ancestors were those you now see in the streets of this city of Atlantis. A marvelous race they were, too. When the rest of the world was still savage and unenlightened, they knew more of the arts and sciences than is known on the surface to-day. The mysteries of the Fourth Dimension they had already solved. Their telescopes were of such power that they knew of the existence of intelligent beings on Mars and Venus. They had conquered the air. They knew of the relation between gravity and magnetism but recently propounded by your Einstein. They were prosperous, happy. Then—but watch!"

Faint sounds of the life of the city came to their ears. A swarm of monoplanes roared past just beneath them. The streets were crowded with rapidly moving vehicles, the roof-tops with air-craft. Then suddenly the scene darkened; a deep rumbling came from the sea. As they watched in fascinated wonder, a great chasm opened up through the heart of the city. Tall buildings swayed and crumbled, falling into heaps of twisted metal and crushed masonry and burying hundreds of the populace in their fall. The confusion was indescribable, the uproar terrific, and within the space of a very few minutes the entire city was a mass of ruins, fully half of the wrecked area having been swallowed up by the heaving waters of the ocean.

haestra stifled a sob. "Thus it began," she stated. "Trovus was first—the city you just saw—then came three more of the cities of the western coast in rapid succession. Computations of the scientists showed that the upheaval was widespread and that the entire continent was to be engulfed in a very short time. The exodus began, but it was too late, and only a few hundred people were able to escape the continent before it was finally destroyed. The ocean became the tomb of two hundred millions. The handful of survivors reached the coast of what is now North America. But the rigors of the climate proved severe and more than three-quarters of them perished within a few days after their planes landed. Then the rest took to the caves along the shore, and for a while were safe."

She manipulated the controls once more and there was a quick shift to another coast, a rugged, wave-beaten shore. Closer they drew until they observed a lofty palisade that extended for miles along the barren waterfront. They saw a fire atop this elevation and active men and women at various tasks within the narrow circle of its warmth. A cave mouth opened at the brink of the precipice near the spot they occupied.

Then came a repetition of the upheaval at Trovus. The ocean rushed in and beat against the cliff with such ferocity that its spray was tossed hundreds of feet in the air. The earth shook and the group of people around the fire made a hasty retreat to the mouth of the cave. The sky darkened and the winds howled with demoniac fury. Quake after quake rent the rugged cliffs: huge sections toppled into the angry waters. Then a great tidal wave swept in and covered everything, cliffs, cave mouths and all. Nought remained where they had been but the seething waters.

ut some escaped!" exulted Phaestra, "and these discovered Theros. Though many miles of the eastern seaboard of your United States were submerged and the coastline entirely altered, these few were saved. Their cave connected with a long passage, a tunnel that led into the bowels of the earth. With the outer entrance blocked by the upheaval they had no alternative save to continue downward."

"They traveled for days and days. Some were overcome by hunger and fell by the wayside. The most hardy survived to reach Theros, a series of enormous caverns that extends for hundreds of miles under the surface of your country. Here they found subterranean lakes of pure water; forests, game. They had a few tools and weapons and they established themselves in this underground world. From that small beginning came this!"

Phaestra's slim fingers worked rapidly at the controls. The scenes shifted in quick succession. They were once more in the present, and seemed to be traveling speedily through the underground reaches of Theros. Now they were racing through a long lighted passage; now over a great city similar to the one in which they had arrived. Here they visited a huge workshop or laboratory; there a mine where radium or cobalt or platinum was being wrested from the vitals of the unwilling earth. Then they visited a typical Theronian household, saw the perfect peace and happiness in which the family lived. Again they were in a large power plant where direct application of the internal heat of the earth as obtained through deep shafts bored into the interior was utilized in generating electricity.

They saw vast quantities of supplies, fifty-ton masses of machinery, moved from place to place as lightly as feathers by use of the gravity discs, those heavily charged plates whose emanations counteracted the earth's attraction. In one busy laboratory they saw an immense television apparatus and heard scientists discussing moot questions with inhabitants of Venus, whose images were depicted on the screen. They witnessed a severe electrical storm in the huge cavern arch over one of the cities, a storm that condensed moisture from the artificially oxygenated and humidified atmosphere in such blinding sheets as to easily explain the necessity for well-roofed buildings in the underground realm. And, in all the speech and activities of the Theronians, there was evident that all-pervading feeling of absolute contentment and freedom from care.

"What I can not understand," said Frank, during a quiet interval, "is why the Theronians have never migrated to the surface. Surely, with all your command of science and mechanics, that would be easy."

"Why? Why?" Phaestra's voice spoke volumes. "Here—I'll show you the reason."

nd again the scene in the sphere changed. They were on the surface and a few years in the past—at Chateau Thierry. They saw their fellow men mangled and broken; saw human beings shot down by hundreds in withering bursts of machine-gun fire; saw them in hand-to-hand bayonet fights; gassed and in delirium from the horror of it all.

They traveled over the ocean; saw a big passenger liner the victim of torpedo fire; saw babies tossed into the water by distracted mothers who jumped in after them to join them in death.

A few years were passed by and they saw gang wars in Chicago and New York; saw militia and picketing strikers in mortal combat; saw wealthy brokers and bank presidents turn pistols on themselves following a crash in the stock market; government officials serving penitentiary terms for betrayal of the people's trust; opium dens, speakeasies, sex crimes. It was a fearful indictment.

"Ah, no," said Phaestra kindly, "the surface world has not yet emerged from savagery. We should be unwelcome were we to venture outside. And now we come to the reason for your visit. You come in search of one Edwin Leland, a fellow worker at one time. Your motives are above reproach. But Leland came as a greedy searcher of riches. We brought him within to teach him the error of his ways and to beg him to desist from his efforts at destroying the dome of silver. He alone knew the secret."

"Then you followed him and we took you in for similar reasons, though our scientists found very quickly that your mental reactions were of entirely different type from Leland's and that the secret would be safe in your keeping. Leland remains obdurate. He threatens us with physical violence, and his reactions to the thought-reading machines are of the most treacherous sort. We must keep him with us. He shall remain unharmed, but he must not be allowed to return. That is the story. You two are free to leave when you choose. I ask not that you give your word to keep the secret of 'Silver Dome.' I know it is not necessary."

he lights had resumed their normal glow, and the marvelous sphere returned to its receptacle beneath the floor. Phaestra resumed her seat on the canopied divan. Frank dropped to a seat on the edge of the dais. Tommy and Orrin remained standing, Tommy lost in thought and Orrin stolidly mute. The empress avoided Frank's gaze studiously. Her cheeks were flushed; her eyes bright with emotion.

Frank was first to break the silence. "Leland is in solitary confinement?" he asked.

"For the present he is under guard," replied Phaestra. "He was quite violent and it was necessary to disarm him after he had killed one of my attendants with a shot from his automatic pistol. When he agrees to submit peacefully, he shall be given the freedom of Theros for the remainder of his life."

"Perhaps," suggested Frank, "if I spoke to him...."

"The very thing." Phaestra thanked him with her wondrous eyes.

A high pitched note rang out from behind the hangings, and, in rapid syllables of the language of Theros, a voice broke forth from the concealed amplifiers. Orrin, startled from his stoicism, sprang to the side of his empress. She rose from her seat as the voice completed its excited message.

"It is Leland," she said calmly. "He has escaped and recovered his pistol. I have been told that he is now at large in the palace, terrorizing the household. We have no weapons here, you see."

"Good God!" shouted Frank. "Suppose he should come here?"

e jumped to his feet just as a shot rang out in the antechamber. Orrin dashed to the portal when a second shot spat forth from the automatic which must certainly be in the hands of a madman. The doors swung wide and Leland, hair disarranged and bloodshot eyes staring, burst into the room. Orrin went down at the next shot and the hardly recognizable scientist advanced toward the dais.

When he saw Frank and Tommy he stopped in his tracks. "So you two have been following me!" he snarled. "Well, you won't keep me from my purpose. I'm here to kill this queen of hell!"

Once more he raised his automatic, but Frank had been watching closely and he literally dove from the steps of the dais to the knees of the deranged Leland. As beautiful a tackle as he had ever made in his college football days laid the maniac low with a crashing thud that told of a fractured skull. The bullet intended for Phaestra went wide, striking Tommy in the shoulder.

Spun half way around by the impact of the heavy bullet, Tommy fought to retain his balance. But his knees went suddenly awry and gave way beneath him. He crumpled helplessly to the floor, staring foolishly at the prostrate figure of Leland and at Frank, who had risen to his feet and now faced the beautiful empress of Theros. Strange lights danced before Tommy's eyes, and he found it difficult to keep the pair in focus. But he was sure of one thing—his pal was unharmed. Then the two figures seemed to merge into one and he blinked his eyes rapidly to clear his failing vision. By George, they were in each other's arms! Funny world—above or below—it didn't seem to make any difference. But it was a tough break for Frank—morganatic marriage and all that. No chance—well—

Tommy succumbed to his overpowering drowsiness.

he awakening was slow, but not painful. Rather there was a feeling of utter contentment, of joy at being alive. A delicious languor pervaded Tommy's being as he turned his head on a snow white silken pillow and stared at the figure of the white-capped nurse who was fussing with the bottles and instruments that lay on an enameled table beside the bed. Memory came to him immediately. He felt remarkably well and refreshed. Experimentally he moved his left shoulder. There was absolutely no pain and it felt perfectly normal. He sat erect in his surprise and felt the shoulder with his right hand. There was no bandage, no wound. Had he dreamed of the hammer blow of that forty-five caliber bullet?

His nurse, observing that her patient had recovered consciousness, broke forth in a torrent of unintelligible Theronian, then rushed from the room.

He was still examining his unscarred shoulder in wonder, when the nurse returned, with Frank Rowley at her heels. Frank laughed at the expression of his friend's face.

"What's wrong, old-timer?" he asked.

"Why—I—thought that fool of a Leland had shot me in the shoulder," stammered Tommy, "but I guess I dreamed it. Where are we? Still in Theros?"

"We are." Frank sobered instantly, and Tommy noted with alarm that his usually cheerful features were haggard and drawn and his eyes hollow from loss of sleep. "And you didn't dream that Leland shot you. That shoulder of yours was mangled and torn beyond belief. He was using soft nosed bullets, the hell-hound!"

"Then how—?"

ommy, these Theronians are marvelous. We rushed you to this hospital and a half-dozen doctors started working on you at once. They repaired the shattered bones by an instantaneous grafting process, tied the severed veins and arteries and closed the gaping wound by filling it with a plastic compound and drawing the edges together with clamps. You were anaesthetized and some ray machine was used to heal the shoulder. This required but ten hours and they now say that your arm is as good as ever. How does it feel?"

"Perfectly natural. In fact I feel better than I have in a month." Tommy observed that the nurse had left the room and he jumped from his bed and capered like a school boy.

This drew no sign of merriment from Frank, and Tommy scrutinized him once more in consternation. "And you," he said, "what is wrong with you?"

"Don't worry about me," replied Frank impatiently. Then, irrelevantly, he said "Leland's dead."

"Should be. I knew we shouldn't have started out to help him. But, Frank, I'm concerned about you. You look badly." Tommy was getting into his clothes as he spoke.

"Forget it, Tommy. You've been sleeping for two days, you know—part of the cure—and I haven't had much rest during that time. That is all."

"It's that Phaestra woman," Tommy accused him.

"Well, perhaps. But I'll get over it, I suppose. Tommy, I love her. But there's no chance for me. Haven't seen her since the row in the palace. Her council surrounds her continually and I have been advised to-day that we are to be returned as quickly as you are up and around. That means immediately now."

"Good. The sooner the better. And you just forget about this queen as soon as you are able. She's a peach, of course, but not for you. There's lots more back in little old New York." But Frank had no reply to this sally.

here came a knock at the door and Tommy called, "Come in."

"I see you have fully recovered," said the smiling Theronian who entered at the bidding, "and we are overjoyed to know this. You have the gratitude of the entire realm for your part in the saving of our empress from the bullets of the madman."

"I?"

"Yes. You and your friend. And now, may I ask, are you ready to return to your own land?"

Tommy stared. "Sure thing," he said, "or rather, I will be in a few minutes."

"Thank you. We shall await you in the transmitting room." The Theronian bowed and was gone.

"Well, I like that," said Tommy. "He hands me an undeserved compliment and then asks how soon we can beat it. A 'here's your hat, what's your hurry' sort of thing."

"It's me they're anxious to be rid of," remarked Frank, shrugging his broad shoulders, "and perhaps it is just as well."

"You bet it is!" agreed Tommy enthusiastically, "and I'm in favor of making it good and snappy." He completed his toilet as rapidly as possible and then turned to face the down-hearted Frank.

"How do we go? The way we came?" he asked.

o, Tommy. They have closed off the shaft that led from the cavern of the silver dome. They are taking no more chances. It seems that the shaft down which we floated was constructed by the Theronians; not by Leland. They had used it and the gravity disc to transport casual visitors to the surface, who occasionally mixed with our people in order to learn the languages of the upper world and to actually touch and handle the things they were otherwise able to see only through the medium of Silver Dome and the crystal spheres. Further visits to the surface are now forbidden, and we are to be returned by a remarkable process of beam transmission of our disintegrated bodies."

"Disintegrated?"

"Yes. It seems they have learned to dissociate the atoms of which the human body is composed and to transmit them to any desired point over a beam of etheric vibrations, then to reassemble them in the original living condition."

"What? You mean to say we are to be shot to the surface through the intervening rock and earth? Disintegrated and reintegrated? And we'll not even be bent, let alone busted?"

his time he was rewarded by a laugh. "That's right. And I have gone through the calculations with one of the Theronian engineers and can find no flaw in the scheme. We're safe in their hands."

"If you say so, Frank, it's okay with me. Let's go!"

Reluctantly his friend lifted his athletic bulk from the chair. In silence he led the way to the transmitting room of the Theronian scientists.

Here they were greeted by two savants with whom Frank was already acquainted, Clarux and Rhonus by name. A bewildering array of complex mechanisms was crowded into the high-ceilinged chamber and, prominent among them, was one of the crystal spheres, this one of somewhat smaller size than the one in the palace of Phaestra.

"Where do you wish to arrive?" asked Clarux.

"As near to my automobile as possible," replied Frank, taking sudden interest in the proceedings. "It is parked in the lane between Leland's house and the road."

Tommy looked quickly in his direction, encouraged by the apparent change in his attitude. The scientists proceeded to energize the crystal sphere. They were bent upon speeding the parting guests. Their beloved empress was to be saved from her own emotions.

Quick adjustments of the controls resulted in the locating of Frank's car, which was still buried to its axles in snow. The scene included Leland's house, or rather its site, for it appeared to have been utterly demolished by some explosion within.

ommy raised questioning eyebrows.

"It was necessary," explained Rhonus, "to destroy the house in obliterating all traces of our former means of egress. It has been commanded that you two be returned safely, and we are authorized to trust implicitly in your future silence regarding the existence of Theros. This is satisfactory, I presume?"

Both Tommy and Frank nodded agreement.

"Are you ready, gentlemen?" asked Clarux, who was adjusting a mechanism that resembled a huge radio transmitter. Its twelve giant vacuum tubes glowed into life as he spoke.

"We are," chimed the two visitors.

They were requested to step to a small circular platform that was raised about a foot from the floor by means of insulating legs. Above the table there was an inverted bowl of silver in the shape of a large parabolic reflector.

"There will be no alarming sensations," averred Clarux. "When I close the switch the disintegrating energy from the reflector above will bathe your bodies for a moment in visible rays of a deep purple hue. You may possibly experience a slight momentary feeling of nausea. Then—presto!—you have arrived."

"Shoot!" growled Frank from his position on the stand.

Clarux pulled the switch and there was a murmur as of distant thunder. Tommy blinked involuntarily in the brilliant purple glow that surrounded him. Then all was confusion in the transmitting room. Somebody had rushed through the open door shouting, "Frank! Frank!" It was the empress Phaestra.

n a growing daze Tommy saw her dash to the platform, seize Frank in a clutch of desperation. There was a violent wrench as if some monster were twisting at his vitals. He closed his eyes against the blinding light, then realized that utter silence had followed the erstwhile confusion. He sat in Frank's car—alone.

The journey was over, and Frank was left behind. With awful finality it came to him that there was nothing he could do. It was clear that Phaestra had wanted his pal, needed him—come for him. From the fact that Frank remained behind it was evident that she had succeeded in retaining him. A sickening fear came to Tommy that she had been too late; that Frank's body was already partly disintegrated and that he might have paid the price of her love with his life. But a little reflection convinced him that if this were the case a portion of his friend's body would have reached the intended destination. Then, unexplainably, he received a mental message that all was well.

onsiderably heartened, he pressed the starter button and the cold motor of Frank's coupe turned over slowly, protestingly. Finally it coughed a few times, and, after considerable coaxing by use of the choke, ran smoothly. He proceeded to back carefully through the drifts toward the road, casting an occasional regretful glance in the direction of the demolished mansion.

He would have some explaining to do when he returned to New York. Perhaps—yes, almost certainly, he would be questioned by the police regarding Frank's disappearance. But he would never betray the trust of Phaestra. Who indeed would believe him if he told the story? Instead, he would concoct a weird fabrication regarding an explosion in Leland's laboratory, of his own miraculous escape. They could not hold him, could not accuse him of murder without producing a body—the corpus delicti, or whatever they called it.

Anyway, Frank was content. So was Phaestra.

Tommy swung the heavy car into the road and turned toward New York, alone and lonely—but somehow happy; happy for his friend.