It clanked gently and wavered where it lay in the ooze. There was a cloud of stirred-up mud, as if it had emitted jets of water from its under parts. It wabbled to one side and the other, straining, and presently its body was free, and a foot or two and then four or five feet of its tail—but it still writhed and wabbled spasmodically—and then suddenly it left the sea floor and floated free.
But only for a moment. Almost immediately its tail swung free, the Wabbler spat out bubbles and descended gently to the bottom again. It rested upon the tip of its tail. It spat more bubbles. One—two—three feet of its tail rested on the mud. It waited. Presently the flood tide moved it again.
It floated always with the current. Once it came to a curve in the deeper channel to which it had found its way, and the tide tended to sweep it up and out beyond the channel. But its tail resisted the attempt. In the end, the Wabbler swam grandly back to the deeper water. The current was stronger there. It went on and on at a magnificent two knots.
But when the current slowed again as the time of the tide change neared, the Wabbler stopped again. It swung above the yard-length of its tail upon the mud. Its brain went tick-tick-tick-tick and it made noises. It dribbled bubbles. It sank, and checked, and dribbled more bubbles, and sank cautiously again—It came cautiously to rest in the mud.
During this time of waiting, the Wabbler heard many sounds. Many times during slack tide, and during ebb tide, too, the water brought humming, purring noises of engines. Once a boat came very near. There was a curious hissing sound in the water. Something—a long line—passed very close overhead. A minesweeper and a minesweep patrolled the sea, striving to detect and uproot submarine mines. But the Wabbler had no anchor cable for the sweep to catch. It lay impassively upon the bottom. But its eyes stared upward with a deadly calm until the minesweeper passed on its way.
Once more during the light hours the Wabbler shook itself free of the bottom ooze and swam on with the tide. And once more—with another wait on the mud while the tide flowed out—at night. But day and night meant little to the Wabbler. Its ticking brain went on tirelessly. It rested, and swam, and swam, and rested, with a machinelike and impassive pertinacity, and always it moved toward places where the tide moved faster and with channels more distinct.
At last it came to a place where the water was no more than forty feet deep, and a distinct greenish-blue light came down from the surface sunshine. In that light the Wabbler was plainly visible. It had acquired a coating of seaweed and slime which seemed to form a sort of aura of wavering greenish tentacles. Its seeming eyes appeared now to be small and snakelike and very wise and venemous. It was still chinless, and its trailing tail made it seem more than ever like some bodiless demon out of a metallic hell. And now it came to a place where for a moment its tail caught in some minor obstruction, and as it tugged at the catch, one of its brothers floated by. It passed within twenty feet of the fourth Wabbler, and they could see each other clearly. But the fourth Wabbler was trapped. It wavered back and forth in the flood tide, trying to pull free, as its fellow swam silently and implacably onward.
Some twenty minutes after that passage there was a colossal explosion somewhere, and after that very many fuzzy, purring noises in the sea. The Wabbler may have known what had happened, or it may not. A submarine net across a harbor entrance is not a thing of which most creatures have knowledge, but it was part of the Wabbler's environment. Its tick-tick-tick-ticking brain may have interpreted the explosion quite correctly as the destiny of its brother encountering that barrier. It is more likely that the brain only noted with relief that the concussion had broken the grip of the obstruction in the mud. The Wabbler went onward in the wake of its fellow. It went sedately, and solemnly, and with a sort of unholy purposefulness, following the tidal current. Presently there was a great net that stretched across the channel, far beyond any distance that the Wabbler could be expected to see. But right where the Wabbler would pass, there was a monstrous gaping hole in that net. Off to one side there was the tail of another Wabbler, shattered away from that other Wabbler's bulk.
The fourth Wabbler went through the hole. It was very simple indeed. Its tail scraped for a moment, and then it was inside the harbor. And then the tick-tick-ticking of the Wabbler's brain was very crisp and incisive indeed, because this was its chance for the accomplishment of its destiny. It listened for sounds of engines, estimating their loudness with an uncanny precision, and within its rounded brainpan it measured things as abstract as variations in the vertical component of terrestrial magnetism. There were many sounds and many variations to note, too, because surface craft swarmed about the scene of a recent violent explosion. Their engines purred and rumbled, and their steel hulls made marked local changes in magnetic force. But none of them came quite close enough to the Wabbler to constitute its destiny.
It went on and on as the flood tide swept in. The harbor was a busy one, with many small craft moving about, and more than once in these daylight hours flying things alighted upon the water and took off again. But it happened that none came sufficiently near. An hour after its entrance into the harbor the Wabbler was in a sort of eddy, in a basin, and it made four slow, hitching circuits about the same spot—during one of which it came near to serried ranks of piling—before the time of slack water. But even here the Wabbler, after swaying a little without making progress for perhaps twenty minutes, made little clanking noises inside itself and dribbled out bubbles and eased itself down in the mud to wait.
It lay there, canted a little and staring up with its small, round, seeming eyes with a look of unimpassioned expectancy. Small boats roved overhead. Once engines rumbled, and a wooden-hulled craft swam on the surface of the water to the very dock whose pilings the Wabbler had seen. Then creaking sounds emanated from those pilings. The Wabbler may have known that unloading cranes were at work. But this was not its destiny either.
There came other sounds of greater import. Clankings of gears. A definite, burning rush of water. It continued and continued. The Wabbler could not possibly be expected to understand, of course, that such burbling underwater sounds are typical of a drydock being filled—the filling beginning near low tide when a great ship is to leave at high. Especially, perhaps, the Wabbler could not be expected to know that a great warship had occupied a vastly important drydock and that its return to active service would restore much power to an enemy fleet. Certainly it could not know that another great warship waited impatiently to be repaired in the same basin. But the restless tick-tick-tick-tick which was the Wabbler's brain was remarkably crisp and incisive.
When flood tide began once more, the Wabbler jetted water and wabbled to and fro until it broke free of the bottom. It hung with a seeming impatience—wreathed in seaweed and coated with greenish slime—above the tail which dangled down to the harbor mud. It looked alive, and inhuman, and chinless, and it looked passionately demoniac, and it looked like something out of a submarine Gehenna. And, presently, when the flood tide began to flow and the eddy about the docks and the dry dock gates began, the Wabbler inched as if purposefully toward the place where the water burbled through flooding valves.
Sounds in the air did not reach the Wabbler. Sounds under water did. It heard the grinding rumble of stream winches, and it heard the screeching sound as the drydock gates swung open. They were huge gates, and they made a considerable eddy of their own. The Wabbler swam to the very center of that eddy and hung there, waiting. Now, for the first time, it seemed excited. It seemed to quiver a little. Once when it seemed that the eddy might bring it to the surface, it bubbled patiently from the vent which appeared to be a mouth. And its brain went tick-tick-tick-tick within it, and inside its brainpan it measured variations in the vertical component of terrestrial magnetism, and among such measurements it noted the effect of small tugs which came near but did not enter the drydock. They only sent lines within, so they could haul the warship out. But the tugs were not the Wabbler's destiny either.