All the grief had gone long ago; he felt no pain at being an exile in his own world, no ache to see once more the faces of friends he had known in the days when he counted all space his empire. There was only a wistful sadness, not even wholly unpleasant, and a mild regret for the inconstancy of sorrow.
Don’s voice broke into his reverie, which had never taken his attention away from his crowded instrument panel.
“We’re just passing my record, Walt. Ten thousand’s the deepest I’ve ever been.”
“And we’re only halfway there. Still, what difference does it make if you’ve got the right ship? It just takes a bit longer to go down, and a bit longer to come up. These tubs would still have a safety factor of five at the bottom of the Philippine Trench.”
“That’s true enough, but you can’t convince me there’s no psychological difference. Don’t you feel two miles of water on your shoulders?”
It was most unlike Don to be so imaginative; usually it was Franklin who made such remarks and was promptly laughed at. If Don was getting moody, it would be best to give him some of his own medicine.
“Tell me when you’ve got to start bailing,” said Franklin. “If the water gets up to your chin, we’ll turn back.”
He had to admit that the feeble joke helped his own morale. The knowledge that the pressure around him was rising steadily to five tons per square inch did have a definite effect on his mind—an effect he had never experienced in shallow-water operations where disaster could be just as instantaneous, just as total. He had complete confidence in his equipment and knew that the sub would do all that he asked it to; but he still felt that curious feeling of depression which seemed to have taken most of the zest out of the project into which he had put so much effort.
Five thousand feet lower down, that zest returned with all its old vigor. They both saw the echo simultaneously, and for a moment were shouting at cross purposes until they remembered their signals discipline. When silence had been restored, Franklin gave his orders.
“Cut your motor to quarter speed,” he said. “We know the beast’s very sensitive and we don’t want to scare it until the last minute.”
“Can’t we flood the bow tanks and glide down?”
“Take too long—he’s still three thousand feet below. And cut your sonar to minimum power; I don’t want him picking up our pulses.” The animal was moving in a curiously erratic path at a constant depth, sometimes making little darts to right or left as if in search of food. It was following the slopes of an unusually steep submarine mountain, which rose abruptly some four thousand feet from the sea bed. Not for the first time, Franklin thought what a pity it was that the world’s most stupendous scenery was all sunk beyond sight in the ocean depths. Nothing on the land could compare with the hundred-mile-wide canyons of the North Atlantic, or the monstrous potholes that gave the Pacific the deepest soundings on earth.
They sank slowly below the summit of the submerged mountain—a mountain whose topmost peak was three miles below sea level. Only a little way beneath them now that mysteriously elongated echo seemed to be undulating through the water with a sinuous motion which reminded Franklin irresistibly of a snake. It would, he thought, be ironic if the Great Sea Serpent turned out to be exactly that. But that was impossible, for there were no water-breathing snakes.
Neither man spoke during the slow and cautious approach to their goal. They both realized that this was one of the great moments of their lives, and wished to savor it to the full. Until now, Don had been mildly skeptical, believing that whatever they found would be no more than some already-known species of animal. But as the echo on the screen expanded, so its strangeness grew. This was something wholly new.
The mountain was now looming above them; they were skirting the foot of a cliff more than two thousand feet high, and their quarry was less than half a mile ahead. Franklin felt his hand itching to throw on the ultraviolet searchlights which in an instant might solve the oldest mystery of the sea, and bring him enduring fame. How important to him was that? he asked himself, as the seconds ticked slowly by. That it was important, he did not attempt to hide from himself. In all his career, he might never have another opportunity like this…
Suddenly, without the slightest warning, the sub trembled as if struck by a hammer. At the same moment Don cried out: “My God—what was that?”
“Some damn fool is letting off explosives,” Franklin replied, rage and frustration completely banishing fear. “Wasn’t everyone notified of our dive?”
“That’s no explosion. I’ve felt it before—it’s an earthquake.”
No other word could so swiftly have conjured up once more all that terror of the ultimate depths which Franklin had felt brushing briefly against his mind during their descent. At once the immeasurable weight of the waters crushed down upon him like a physical burden; his sturdy craft seemed the frailest of cockleshells, already doomed by forces which all man’s science could no longer hold at bay.
He knew that earthquakes were common in the deep Pacific, where the weights of rock and water were forever poised in precarious equilibrium. Once or twice on patrols he had felt distant shocks—but this time, he felt certain, he was near the epicenter.
“Make full speed for the surface,” he ordered. “That may be just the beginning.”
“But we only need another five minutes,” Don protested. “Let’s chance it, Walt.”
Franklin was sorely tempted. That single shock might be the only one; the strain on the tortured strata miles below might have been relieved. He glanced at the echo they had been chasing; it was moving much faster now, as if it, too, had been frightened by this display of Nature’s slumbering power.
“We’ll risk it,” Franklin decided. “But if there’s another one we’ll go straight up.”
“Fair enough,” answered Don. “I’ll bet you ten to one—”
He never completed the sentence. This time the hammer blow was no more violent, but it was sustained. The entire ocean seemed to be in travail as the shock waves, traveling at almost a mile a second, were reflected back and forth between surface and sea bed. Franklin shouted the one word “Up!” and tilted the sub as steeply as he dared toward the distant sky.
But the sky was gone. The sharply defined plane which marked the water-air interface on the sonar screen had vanished, replaced by a meaningless jumble of hazy echoes. For a moment Franklin assumed that the set had been put out of action by the shocks; then his mind interpreted the incredible, the terrifying picture that was taking shape upon the screen.
“Don,” he yelled, “run for the open sea—the mountain’s falling!”
The billions of tons of rock that had been towering above them were sliding down into the deep. The whole face of the mountain had split away and was descending in a waterfall of stone, moving with a deceptive slowness and an utterly irresistible power. It was an avalanche in slow motion, but Franklin knew that within seconds the waters through which his sub was driving would be torn with falling debris.
He was moving at full speed, yet he seemed motionless. Even without the amplifiers, he could hear through the hull the rumble and roar of grinding rock. More than half the sonar image was now obliterated, either by solid fragments or by the immense clouds of mud and silt that were now beginning to fill the sea. He was becoming blind; there was nothing he could do but hold his course and pray.
With a muffled thud, something crashed against the hull and the sub groaned from end to end. For a moment Franklin thought he had lost control; then he managed to fight the vessel back to an even keel. No sooner had he done this than he realized he was in the grip of a powerful current, presumably due to water displaced by the collapsing mountain. He welcomed it, for it was sweeping him to the safety of the open sea, and for the first time he dared to hope.
Where was Don? It was impossible to see his echo in the shifting chaos of the sonar screen. Franklin switched his communication set to high power and started calling through the moving darkness. There was no reply; probably Don was too busy to answer, even if he had received the signal.
The pounding shock waves had ceased; with them had gone the worst of Franklin’s fears. There was no danger now of the hull being cracked by pressure, and by this time, surely, he was clear of the slowly toppling mountain. The current that had been aiding his engines had now lost its strength, proving that he was far away from its source. On the sonar screen, the luminous haze that had blocked all vision was fading minute by minute as the silt and debris subsided.