If my friend the engineer had not told me the Tube was dangerous, I would not have bought a ticket on that fatal night, and the world would never have learned the story of the Golden Cavern and the City of the Dead. Having therefore, according to universal custom, first made my report as the sole survivor of the much-discussed Undersea Tube disaster to the International Committee for the Investigation of Disasters, I am now ready to outline that story for the world. Naturally I am aware of the many wild tales and rumors that have been circulated ever since the accident, but I must ask my readers to bear with me while I attempt to briefly sketch, not only the tremendous difficulties to be overcome by the engineers, but also the wind-propulsion theory which was made use of in this undertaking; because it is only by understanding something of these two phases of the Tube’s engineering problems that one can understand the accident and its subsequent revelations.

It will be recalled by those who have not allowed their view of modern history to become too hazy, that the close of the twentieth century saw a dream of the engineering world at last realized--the completion of the long-heralded undersea railroad. It will also be recalled that the engineers in charge of this stupendous undertaking were greatly encouraged by the signal success of the first tube under the English Channel, joining England and France by rail. However, it was from the second tube across the Channel and the tube connecting Montreal to New York, as well as the one connecting New York and Chicago, that they obtained some of their then radical ideas concerning the use of wind power for propulsion. Therefore, before the Undersea Tube had been completed, the engineers in charge had decided to make use of the new method in the world’s longest tunnel, and upon that decision work was immediately commenced upon the blue-prints for the great air pumps that were to rise at the two ends--Liverpool and New York. However, I will touch upon the theory of wind-propulsion later and after the manner in which it was explained to me.

It will be recalled that after great ceremonies, the Tube was begun simultaneously at the two terminating cities and proceeded through solid rock--low enough below the ocean floor to overcome the terrible pressure of the body of water over it, and yet close enough to the sea to overcome the intensity of subterranean heat. Needless to say, it was an extremely hazardous undertaking, despite the very careful surveys that had been made, for the little parties of workmen could never tell when they would strike a crack or an unexpected crevice that would let down upon them with a terrible rush, the waters of the Atlantic. But hazard is adventure, and as the two little groups of laborers dug toward each other, the eyes of the press followed them with more persistent interest than it has ever followed the daily toil of any man or group of men, either before or since.

Once the world was startled by the “extree-ee--” announcing that the English group had broken into an extinct volcano, whose upper end had apparently been sealed ages before, for it contained not water but air--curiously close and choking perhaps, but at least it was not the watery deluge of death. And then came the great discovery. No one who lived through that time will forget the thrill that quickened the pulse of mankind when the American group digging through a seam of old lava under what scientists call the “ancient ridge,” broke into a sealed cavern which gleamed in the probing flashlights of the workers like the scintillating points of a thousand diamonds. But when they found the jeweled casket, through whose glass top they peered curiously down upon the white body of a beautiful woman, partly draped in the ripples of her heavy, red hair, the world gasped and wondered. As every school child knows, the casket was opened by curious scientists, who flocked into the tube from the length of the world, but at the first exposure to the air, the strange liquid that had protected the body vanished, leaving in the casket not the white figure, but only a crumbling mass of grey dust. But the questions that the finding of the cave had raised remained unanswered.

Who was this woman? How did she get into the sealed cavern? If she had been the court favorite of that mythical kingdom, now sunk beneath the waves, and had been disposed of in court intrigue, why would her murderers have buried her in such a casket? How had she been killed? An unknown poison? Perhaps she had been a favorite slave of the monarch. This view gained many converts among the archaeologists who argued that from all the evidence we have available, the race carrying the Iberian or Proto-Egyptian culture, long thought to have been the true refugees from sinking Atlantis, were a slight dark-haired race. Therefore this woman must have been a captive. Geologists, analyzing the lava, announced that it had hardened in air and not in water, while anthropologists classed the skull of the woman as essentially more modern than either the Neanderthal or Cro-Magnon types. But the engineers, secretly fuming at the delay, finally managed to fill up the cave and press on with their drills.

Then following the arguments that still flourished in the press, came a tiny little news article and the first message to carry concern to the hearts of the engineers. The sea had begun to trickle in through one slight crack. Perhaps it was only because the crevice was located on the English side of the now famous “ancient ridge” that the article brought forth any notice at all. But for the engineers it meant the first warning of possibly ultimate disaster. They could not seal the crack, and pumps were brought into play. However, as a month wore on, the crack did not appear to widen to any material extent and the danger cry of a few pessimists was forgotten.

Finally, it will be remembered, that sounders listening in the rocks heard the drillers of the other party, and then with wild enthusiasm the work was pushed on to completion. The long Tube had been dug. Now it only remained for the sides at the junction to be enlarged and encased with cast iron, while the work of setting up the great machines designed to drive the pellet trains through, was also pushed on to its ultimate end. Man had essayed the greatest feat of engineering ever undertaken in the history of the planet, and had won. A period of wild celebration greeted the first human beings to cross each direction below the sea.

Did the volume of water increase that was carried daily out of the Tube and dumped from the two stations? If it did, the incident was ignored by the press. Instead, the fact that some “cranks” persisted in calling man’s latest toy unsafe, only attracted more travel. The Undersea Tube functioned on regular schedule for three years, became the usual method of ocean transit.

This was the state of matters, when on the fourth of March last, our textile company ordered me to France to straighten out some orders with the France house, the situation being such that they preferred to send a man. Why they did not use radio-vision I do not care to state, as this is my company’s business.

Therefore, upon entering my apartment, I was in the midst of packing when the television phone called me. The jovial features of “Dutch” Higgins, my one-time college room-mate and now one of the much-maligned engineers of the Undersea Tube, smiled back at me from the disk.

“Where are you? I thought we had a sort of dinner engagement at my apartment, Bob.”

“By gollies I forgot, Dutch. I’ll be right over--before it gets cold.”

Then immediately I turned the knob to the Municipal Aerial-car yards, and ordered my motor, as I grabbed my hat and hurried to the roof. In due time, of course, I sprang the big surprise of the evening, adding:

“And, of course, I’m going by the Tube, I feel sort of a half-partnership in it because you were one of the designers.”

A curious half-pained look crossed his face. We had finished our meal, and were smoking with pushed-back chairs. He finished filling his pipe, and scowled.

“Well? Why don’t you say something? Thought you’d be--well, sort of pleased.”

He struck his automatic lighter and drew in a long puff of smoke before answering.

“Wish you’d take another route, Bob.”

“Take another route?”

“Yes. If you want it straight, the Tube is not safe.”

“You are joking.”

But as I looked into his cold, thoughtful blue eyes, I knew he had never been more serious.

“I wish that you would go by the Trans-Atlantic Air Liners. They are just as fast.”

“But you used to be so enthusiastic about the Tube, Dutch! Why I remember when it was being drilled that you would call me up at all kinds of wild hours to tell me the latest bits of news.”

He nodded slowly.

“Yes, that was in the days before the crack.”

“Yet you expected to take care of possible leaks, you know,” I countered.

“But this crack opened after the tunnel had been dug past it, and lately it has opened more.”

“Are the other engineers alarmed?”

“No. We are easily taking care of the extra water and again the opening seems to remain at a stationary width as it has for the past three years. But we cannot caulk it.”

“Are you going to publish these views?”

“No. I made out a minority report. I can do no more.”

“Dutch, you are becoming over-cautious. First sign of old age.”

“Perhaps,” with the old smile.

“But after all it is now more than three years since we have had a talk on the Tube. After it began to function as well as the Air-Express you sort of lost interest in it.”

“And the world did too.”

“Certainly--but the public ever was a fickle mistress. Who said that before me?”

He laughed and blew out a long puff of smoke.

“Everyone, Bob.”

“But as to the Tube, if I cross under the sea, I would want to be as well informed on the road as I was three years ago. Now in the meantime, you have dropped interest in the long tunnel while I have become more interested in textiles--with the result that I have forgotten all I ever did know--which compared to your grasp of the details, was little enough.”

But his face showed none of the old-time animation on the subject. What a different man, I mused to myself, from that enthusiastic engineering student that I used to come upon dreaming over his blue-prints. He was considered “half-cracked” in those days when he would enthuse over his undersea railroad, but his animated face was lit with inspiration. Now the light was gone.

“Well, Dutch, how about it? Aren’t you going to make me that brief little sketch of the length plan and cross-section of the Tube? I remember your sketch of it in college, and it tends to confuse me with the real changes that were made necessary when the wind-propulsion method was adopted.”

“All right, old timer. You remember that the Tube was widened at the sides in order that we could make two circular tubes side by side--one going each way.”

“I had forgotten that they were circular.”

“That is because of the pressure. A circle presents the best resistance,” and picking an odd envelope from his pocket, he made the following sketch and passed it to me.

[Illustration:--CROSS-SECTION OF TUBE--]

I nodded as I recognized the cross-section.

“Now the plan of the thing is like this,” he added, putting aside his pipe and pulling a sheet of paper from the corner of his desk.

Rapidly, with all his old accuracy, he sketched the main plan and leaned over as he handed it to me.

[Illustration:--PLAN OF UNDER-SEA TUBE--]

“You see,” he explained, picking up his pipe again, “both pumps work at one time--in fact, I should say all four, because this plan is duplicated on the English side. On both ends then, a train is gently pushed in by an electric locomotive. A car at a time goes through the gate so that there is a cushion of air between each car. The same thing happens at Liverpool. Now, when the due train comes out of the suction tube, it goes on out the gate, but the air behind it travels right on around and comes in behind the train that is leaving.”