The water rose above their bow windows, but suddenly and inexplicably it began to subside again. A man waded by around the bow of Abbot"s machine.
"They"ve crashed in the door, and are pumping out the water again!"
exclaimed Abbot. "We"re trapped!"
"Not yet!" grimly replied the girl at his side. "Can you work the radio door controls?"
"Yes."
"Then quick! Open the doors into the lock!"
He pressed a b.u.t.ton. Ahead of them two gates swung inward, followed by a deluge of water.
"Come on!" spoke the girl. "Full speed ahead, before the water gets too low."
Abbot did so. Out into the lock they sped, in the face of the surging current. Then Abbot pushed another b.u.t.ton to close the gates behind them. But the water continued to fall, and they grounded before they reached the end of the lock. Quite evidently the rush of the current had kept the doors from closing behind them. The city was being flooded through the broken door of the storeroom.
But Abbot opened the next gate, and again they breasted the incoming torrent. This time, although the level continued to fall, their craft did not quite ground.
"They must have got the gates shut behind us at last," said he, as he opened the next set and pressed on.
And then he had an idea. Why not omit to close any further gates behind him? As a result, the sea pressure would eventually break down the inmost barriers, and destroy the city as effectively as Dolf"s bomb would have done. But he said nothing to Milli of this plan: she might wish to save her people.
Gate after gate they pa.s.sed. This was too simple. A few more locks and they would be out in open water. The submarine of Hakin and Romehl swept by--evidently to let George and Milli know their presence--and then dropped behind again. But was it their two friends after all? It might have been some enemy! They could not be sure.
This uncertainty cast a chill of apprehension over them, which was immediately heightened by the sudden extinguishing of the overhead lights of the tunnel. Abbot pressed the radio b.u.t.ton for the next set of locks, but they did not budge.
"What can be the matter?" he asked frantically.
"My people must have turned off the electric current," Milli replied.
"The gates won"t open without electricity to feed the motors. We"re trapped again."
For a moment they lay stunned by a realization that their escape was blocked.
"Kiss me good-by, dear," breathed Milli. "This is the end."
As the young man reached over to take her in his arms, the submarine was suddenly lifted up and spun backward, end over end: then tumbled and b.u.mped along, as though it were a chip on an angry mountain torrent.
Stunned and bruised and bleeding, the young American finally lost consciousness....
When he came to his senses again, his first words were, "Milli, where are you?"
"My darling!" breathed a voice at his side. "Are you all right?"
"Yes," he replied. "Where are we? What has happened?"
"The entire system of locks must have crashed in and flooded the city," said she.
Instantly Abbott"s mind grasped the explanation of this occurrence: their leaving open so many gates behind them had made it impossible for the few remaining gates ahead to withstand the terrific pressures of the ocean depths, and they had crumpled. But he did not tell Milli his part in this.
She continued, "I was pretty badly shaken up myself, but I"ve got this boat going again, and we"re on our way out of the tunnel. See--I"ve found out how to work our searchlight."
He looked. A broad beam of light from their bow, illuminated the tunnel ahead of them.
Presently another beam appeared, shooting by them from behind.
"Hakin and Romehl!" exclaimed the girl. "Then they"re safe, too!"
The tunnel walls grew rough, then disappeared. They were out in the open sea at last, although still one mile beneath the surface.
But in front of them was an angry seething school of the man-sharks, clearly illumined by the two rays of light. Behind the sharks were a score or more of serpentine steeds.
The sharks saw the two submarines and charged down upon them; but Milli, with great presence of mind, shut off her searchlight and swung sharply to the left.
"Up! Up!" urged the young man, so she turned the craft upward.
On and on they went, with no interference. Presently they turned the light on again, so as to see what progress they were making. But they were making absolutely none! They were merely standing on their tail.
They had reached a height of such relatively low pressure that it took all the churning of their propeller just merely to counteract the great weight of their submarine.
Abbot switched on their chemical gas supply, and as their top fin expanded into a balloon they again began to rise.
One thing, however, perplexed the young man: the water about him seemed jet black rather than blue. They must by now be close to the surface of the sea, where at least a twilight blue should be visible.
Even at the one mile depth in his bathysphere, the water had been brilliant, yet here, almost at the surface, he could see absolutely nothing.
He switched on the searchlight again to make sure that their window wasn"t clouded over; but it wasn"t.
Then suddenly a rippling veil of pale silver appeared ahead; then a blue-black sky and twinkling stars. They had reached the surface, and it was night.
He pointed out the stars to the girl at his side, then swung the nose of the submarine around and showed her the moon.
Where next? George Abbot picked out his position by the stars and headed east. East across the Pacific, toward America.
But soon he noticed that their little craft was dropping beneath the surface. He kept heading up more and more; he threw the lever for more and more chemical gas; yet still they continued to sink.
"Milli!" he exclaimed, "we"ve got to get out of here!"
She clutched him in fear, for to her the pressure of the open sea meant death, certain death. But he pushed her firmly away, and unclamped the lid of the submarine. In another instant he had hauled her out and was battling his way to the surface, while their little boat sunk slowly beneath them.
Milli was an experienced swimmer, for the undersea folk enjoyed the privilege of a large indoor pool. As soon as she found that the open sea did not kill her, she became calm.
Side by side they floated in the moonlight. The sky began to pink in the east. Dawn came, the first dawn that Milli had ever seen.