The generator rumbled and roared, building up to its maximum speed. The whole laboratory quivered from its vibration. The dynamo hummed and whined and the night silence outside seemed to make the noises within more deafening. Tommy Reames ran his eyes again over the power-leads to the monstrous, misshapen coils. Professor Denham bent over one of them, straightened, and nodded. Tommy Reames nodded to Evelyn, and she threw the heavy multiple-pole switch.

There was a flash of jumping current. The masses of metal on the floor seemed to leap into ungainly life. The whine of the dynamo rose to a scream and its brushes streaked blue flame. The metal things on the floor flicked together and were a tube, three feet and more in diameter. That tube writhed and twisted. It began to form itself into an awkward and seemingly impossible shape, while metal surfaces sliding on each other produced screams that cut through the din of the motor and dynamo. The writhing tube strained and wriggled. Then there was a queer, inaudible snap and something gave. A part of the tube quivered into nothingness. Another part hurt the eyes that looked upon it.

And then there was the smell of burned insulation and a wire was arcing somewhere, while thick rubbery smoke arose. A fuse blew out with a thunderous report, and Tommy Reames leaped to the suddenly racing motor-generator. The motor died amid gasps and rumblings. And Tommy Reames looked anxiously at the Fifth-Dimension Tube.

It was important, that Tube. Through it, Tommy Reames and Professor Denham had reason to believe they could travel to another universe, of which other men had only dreamed. And it was important in other ways, too. At the moment Evelyn Denham threw the switch, last-edition newspapers in Chicago were showing headlines about “King” Jacaro’s forfeiture of two hundred thousand dollars’ bail by failing to appear in court. King Jacaro was a lord of racketeerdom.

While Tommy inspected the Tube anxiously, a certain chief of police in a small town upstate was telling feverishly over the telephone of a posse having killed a monster lizard by torchlight, having discovered it in the act of devouring a cow. The lizard was eight feet high, walked on its hind legs, and had a collar of solid gold about its neck. And jewel importers, in New York, were in anxious conference about a flood of untraced jewels upon the market. Their origin was unknown. The Fifth-Dimension Tube ultimately affected all of those affairs, and the Death Mist as well. And—though it was not considered dangerous then—everybody remembers the Death Mist now.

But at the moment Professor Denham stared at the Tube concernedly, his daughter Evelyn shivered from pure excitement as she looked at it, and a red-headed man named Smithers looked impassively from the Tube to Tommy Reames and back again. He’d done most of the mechanical work on the Tube’s parts, and he was as anxious as the rest. But nobody thought of the world outside the laboratory.

Professor Denham moved suddenly. He was nearest to the open end of the Tube. He sniffed curiously and seemed to listen. Within seconds the others became aware of a new smell in the laboratory. It seemed to come from the Tube itself, and it was a warm, damp smell that could only be imagined as coming from a jungle in the tropics. There were the rich odors of feverishly growing things; the heavy fragrance of unknown tropic blossoms, and a background of some curious blend of scents and smells which was alien and luring, and exotic. The whole was like the smell of another planet of the jungles of a strange world which men had never trod. And then, definitely coming out of the Tube, there was a hollow, booming noise.

It had been echoed and re-echoed amid the twistings of the Tube, but only an animal could have made it. It grew louder, a monstrous roar. Then yells sounded suddenly above it—human yells, wild yells, insane, half-gibbering yells of hysterical excitement and blood lust. The beast-thing bellowed and an ululating chorus of joyous screams arose. The laboratory reverberated with the thunderous noise. Then there was the sound of crashing and of paddings, and abruptly the noise was diminishing as if its source were moving farther away. The beast-thing roared and bellowed as if in agony, and the yelling noise seemed to show that men were following close upon its flanks.

Those in the laboratory seemed to awaken as if from a bad dream. Denham was kneeling before the mouth of the Tube, an automatic rifle in his hands. Tommy Reames stood grimly before Evelyn. He’d snatched up a pair of automatic pistols. Smithers clutched a spanner and watched the mouth of the Tube with a strained attention. Evelyn stood shivering behind Tommy.

Tommy said with a hint of grim humor:

“I don’t think there’s any doubt about the Tube having gotten through. That’s the Fifth Dimension planet, all right.”

He smiled at Evelyn. She was deathly pale.

“I—remember—hearing noises like that….”

Denham stood up. He painstakingly slipped on the safety of his rifle and laid it on a bench with the other guns. There was a small arsenal on a bench at one side of the laboratory. The array looked much more like arms for in expedition into dangerous territory than a normal part of apparatus for an experiment in rather abstruse mathematical physics. There were even gas masks on the bench, and some of those converted brass Very pistols now used only for discharging tear- and sternutatory-gas bombs.

“The Tube wasn’t seen, anyhow,” said Professor Denham briskly. “Who’s going through first?”

Tommy slung a cartridge belt about his waist and a gas mask about his neck.

“I am,” he said shortly. “We’ll want to camouflage the mouth of the Tube. I’ll watch a bit before I get out.”

He crawled into the mouth of the twisted pipe.

The Tube was nearly three feet across, each section was five feet long, and there were gigantic solenoids at each end of each section.

It was not an experiment made at random, nor was the world to which it reached an unknown one to Tommy or to Denham. Months before, Denham had built an instrument which would bend a ray of light into the Fifth Dimension and had found that he could fix a telescope to the device and look into a new and wholly strange cosmos.* * “The Fifth-Dimension Catapult”—see the January, 1931, issue of Astounding Stories. He had seen tree-fern jungles and a monstrous red sun, and all the flora and fauna of a planet in the carboniferous period of development. More, by the accident of its placing he had seen the towers and the pinnacles of a city whose walls and towers seemed plated with gold.

Having gone so far, he had devised a catapult which literally flung objects to the surface of that incredible world. Insects, birds, and at last a cat had made the journey unharmed, and he had built a steel globe in which to attempt the journey in person. His daughter Evelyn had demanded to accompany him, and he believed it safe. The trip had been made in security, but return was another matter. A laboratory assistant, Von Holtz, had sent them into the Fifth Dimension, only to betray them. One King Jacaro, lord of Chicago racketeers, was convinced by him of the existence of the golden city of that other world, and that it was full of delectable loot. He offered a bribe past envy for the secret of Denham’s apparatus. And Von Holtz had removed the apparatus for Denham’s return before working the catapult to send him on his strange journey. He wanted to be free to sell full privileges of rapine and murder to Jacaro.

The result was unexpected. Von Holtz could not unravel the secret of the catapult he himself had operated. He could not sell the secret for which he had committed a crime. In desperation he called in Tommy Reames—rather more than an amateur in mathematical physics—showed him Evelyn and her father marooned in a tree-fern jungle, and hypocritically asked for aid.

Tommy’s enthusiastic efforts soon became more than merely enthusiastic. The men of the Golden City remained invisible, but there were strange, half-mad outlaws of the jungles who hated the city. Tommy Reames had watched helplessly as they hunted for the occupants of the steel globe. He had worked frenziedly to achieve a rescue. In the course of his labor he discovered the treachery of Von Holtz as well as the secret of the catapult, and with the aid of Smithers—who had helped to build the original catapult—he made a new small device to achieve the original end.

The whole affair came to an end on one mad afternoon when the Ragged Men captured first an inhabitant of the Golden City, and then Denham and Evelyn in a forlorn attempt at rescue. Tommy Reames went mad. He used a tiny sub-machine gun upon the Ragged Men through the model magnetic catapult he had made, and contrived communication with Denham afterward. Instructed by Denham, he brought about the return of father and daughter to Earth just before Ragged Men and Earthling alike would have perished in a vengeful gas cloud from the Golden City. Even then, though, his triumph was incomplete because Von Holtz had gotten word to Jacaro, and nattily-dressed gunmen raided the laboratory and made off with the model catapult, leaving three bullets in Tommy and one in Smithers as souvenirs.

Now, using the principle developed in the catapult, Tommy and Denham had built a large Tube, and as Tommy climbed along its corrugated interior he knew a good part of what he should expect at the other end. A steady current of air blew past him. It was laden with a myriad unfamiliar scents. The Tube was a tunnel from one set of dimensions to another, a permanent way from Earth to a strange, carboniferous-period planet on which a monstrous dull-red sun shone hotly. Tommy should come out into a tree-fern forest whose lush vegetation would hide the sky, and which furnished a lurking place not only for strange reptilian monsters akin to those of the long-dead past of Earth, but for the bands of ragged, half-mad human beings who were outlaws from the civilization of which Denham and Evelyn had seen proofs.

Tommy reached the third bend in the Tube. By now he had lost all sense of orientation. An object may be bent through one right angle only in two dimensions, and a second perfect right angle—at ninety degrees to all former paths—only in three dimensions. It follows that a third perfect right angle requires four dimensions for existence, and four perfect right angles five. The Tube bent itself through four perfect right angles, and since no human-being can ever have experience of more than three dimensions, plus time, it followed that Tommy was experiencing other dimensions than those of Earth as soon as he passed the third bend. In short, he was in another cosmos.

There was a moment of awful sickness as he passed the third bend. He was hideously dizzy when he passed the fourth. For a time he felt as if he had no weight at all. But then, quite abruptly, he was climbing vertically upward and the soughing of tree-fern fronds was loud in his ears, and suddenly the end of the Tube was under his fingers and he stared out into the world of the Fifth Dimension.

Now a gentle wind blew in his face. Tree-ferns rose to incredible heights above his head, and now and again by the movements of their fronds he caught stray glimpses of unfamiliar stars. There were red stars, and blue ones, and once he caught sight of a clearly distinguishable double star, of which each component was visible to the naked eye. And very, very far away he heard the beastly yellings he knew must be the outlaws, the Ragged Men, feasting horribly on half-scorched flesh torn from the quivering, yet-living flanks of a monstrous reptile.

Something moved, whimpered—and fled suddenly. It sounded like a human being. And Tommy Reames was struck with the utterly impossible conviction that he had heard just that sound before. It was not dangerous, in any case, and he watched, and listened, and presently he slipped from the mouth of the Tube and by the glow of a flashlight stripped foliage from nearby growths and piled it about the Tube’s mouth. And then, because the purpose of the Tube was not adventure but science, he went back down into the laboratory.

The three men, with Evelyn, worked until dawn at the rest of their preparations for the use of the Tube. All that time the laboratory was filled with the heavy fragrance of a tree-fern jungle upon an unknown planet. The heavy, sickly-sweet scents of closed jungle blossoms filled their nostrils. The reek of feverishly growing green things saturated the air. A steady wind blew down the Tube, and it bore innumerable unfamiliar odors into the laboratory. Once a gigantic moth bumped and blundered into the Tube, and finally crawled heavily out into the light. It was scaled, and terrible because of its monstrous size, but it had broken a wing and could not fly. So it crawled with feverish haste toward a brilliant electric light. Its eyes were especially horrible because they were not compound like the moths of Earth. They were single, like those of a man, and were fixed in an expression of utter, fascinated hypnosis. The thing looked horribly human with those eyes staring from an insect’s head, and Smithers killed it in a flash of nerve-racked horror. None of them were able to go on with their work until the thing and its fascinated, staring eyes had been put out of sight. Then they labored on with the smell of the jungles of that unnamed planet thick about them, and noises now and then coming down the Tube. There were roars, and growlings, and once there was a thin high sound which seemed like the far-distant, death-startled scream of a man.