The Professor threw down a large fragment of rock. Seconds elapsed and we heard no splash. The unseen surface was too far below for the noise of the rock's fall to carry on up to us.
"The mystery of this ball of earth on which we live!" murmured the Professor. "Here is this enormous underground body of water. We are far below sea level. Where, then, is it flowing? What does it empty into? Can it be that our planet is honeycombed with such hollows as this we are in? And is each inhabited by some form of life?"
He sighed and shook his head.
"The thought is too big! For, if that were true, wouldn't the seas be drained from the surface of the earth should an accidental passage be formed from the ocean bed down to such a giant river as this beneath us? How little we know!"
The wild clamor of an alarm bell interrupted his musing. From all the city houses poured masses of people, to form in solid lines behind the large well.
In addition to men, there were many women in those lines, tall and strong, ready to stand by their mates as long as life was left them. There were children, too, scarcely in their teens, prepared to fight for the existence of the race. Every able-bodied Zyobite was mustered against the cold-blooded Things that pressed so near.
The arms of these desperate fighters were pitiful compared to our own war weapons. With no need in the city for fighting engines, none had ever been developed. Now the best that could be had was a sort of ax, used for dissecting the mound-fish, and various knives fashioned for peaceful purposes.
Again the bell clamored forth a warning, this time twice repeated. Every hand grasped its weapon. Every eye went hopefully to the hole in the floor on which our immediate fate depended, then valiantly to the section of wall above it.
This quivered perceptibly. A heavy, pointed instrument broke through; was withdrawn; and a hissing stream of water spurted out.
The Quabos were about to break in upon us!
With a crash that made the solid rock tremble, a section of the wall collapsed. It was the top half of the end of the Quabos' tunnel. They had so wrought that the lower half stayed in place--a thing we did not have time to recognize as significant until later.
A solid wall of water, in which writhed dozens of tentacled monsters, was upon us, and we had time for nothing but action.
The ditch had of necessity been placed directly under the Quabos' entrance. The first rush of water carried half over it. With it were borne scores of the cold-blooded invaders.
In an instant we were standing knee deep in a torrent that tore at our footing, while we hacked frantically with knives and axes at the slimy tentacles that reached up to drag us under.
A soft, horrible mass swept against my legs. I was overthrown. A tentacle slithered around my neck and constricted viciously like a length of rotten cable. I sawed at it with the long, notched blade I carried. Choking for air, I felt the pressure relax and scrambled to my knees.
Two more tentacles went around me, one winding about my legs and the other crushing my waist. Two huge eyes glared fiendishly at me.
I plunged the knife again and again into the barrel-shaped head. It did not bleed: a few drops of thin, yellowish liquid oozed from the wounds but aside from this my slashing seemed to make no impression.
In a frenzy I defended myself against the nightmare head that was winding surely toward me. Meanwhile I devoted every energy to keeping on my feet. If I ever went under again-- It seemed to me that the creature was weakening. With redoubled fury I hacked at the spidery shape. And gradually, when it seemed as though I could not withstand its weight and crushing tentacles another second, it slipped away and floated off on the shallow, roaring rapids.
For a moment I stood there, catching my breath and regaining my strength. Shifting, terrible scenes flashed before my eyes.
A tall Zyobite and an almost equally stalwart woman were both caught by one gigantic Quabo which had a tentacle around the throat of each. The man and woman were chopping at the viscous, gruesome head. One of the Thing's eyes was gashed across, giving it a fearsome, blind appearance. It heaved convulsively, and the three struggling figures toppled into the water and were swirled away.
The Professor was almost buried by a Quabo that had all four of its tentacles wound about him. As methodically as though he were in a laboratory dissecting room, he was cutting the slippery lengths away, one by one, till the fourth parted and left him free.
A giant Zyobite was struggling with two of the monsters. He had an ax in each hand, and was whirling them with such strength and rapidity that they formed flashing circles of light over his head. But he was torn down at last and borne off by the almost undiminished flood that gushed from the tunnel.
And now, without warning, a heavy soft body flung against my back, and the accident most to be dreaded in that melee occurred.
I was knocked off my feet! My head was pressed under the water. On my chest was a mass that was yielding but immovable, soft but terribly strong. Animated, firm jelly! I had no chance to use my knife. My arms were held powerless against my sides.
Water filled my nose and mouth. I strangled for breath, heaving at the implacable weight that pinned me helpless. Bright spots swirled before my eyes. There was a roaring in my ears. My lungs felt as though filled with molten lead. I was drowning....
Vaguely I felt the pressure loosen at last. An arm--with good, solid flesh and bone in it--slipped under my shoulders and dragged me up into the air.
"Don't you know--can't drown a fish--holding it under water?" panted a voice.
I opened my eyes and saw Stanley, his face pale with the thrill of battle, his chin jutting forward in a berserk line, his eyes snapping with eager, wary fires.
I grinned up at him and he slapped me on the back--almost completing the choking process started by the salt water I'd inhaled.
"That's better. Now--at it again!"
I don't remember the rest of the tumult. The air seemed filled with loathsome tentacles and bright metal blades. It was a confused eternity until the decreased volume of water in the tunnel gave us a respite....
As the tunnel slowly emptied the pressure dropped, and the incoming flood poured squarely into the trough instead of half over it. From that moment there was very little more for us to do.
Our little army--with about a fourth of its number gone--had only to guard the ditch and see that none of the Quabos caught the edges as they hurtled out of their passage.
For perhaps ten minutes longer the water poured from the break in the wall, with now and then a doomed Quabo that goggled horribly at us as it was dashed down the hole in the floor to whatever awesome depths were beneath.
Then the flow ceased. The last oleaginous corpse was pushed over the edge. And the city, save for an ankle-deep sheet of water that was rapidly draining out the vents in the streets, presented its former appearance.
The Zyobites leaned wearily against convenient walls and began telling themselves how fortunate they were to have been spared what seemed certain destruction.
The Professor didn't share in the general feeling of triumph.
"Don't be so childishly optimistic!" he snapped as I began to congratulate him on the victory his ditch had given us. "Our troubles aren't over yet!"
"But we've proved that we can stand up to them in a hand-to-tentacle fight--"
His thin, frosty smile appeared.
"One of those devils, normally, is stronger than any three men. The only reason all of us weren't destroyed at once is that they were slowly suffocating as they fought. The foot and a half of water we were in wasn't enough to let their gills function properly. Now if they were able to stand right up to us and not be handicapped by lack of water to breathe ... I wonder.... Is that part of their plan? Is there any way they could manage ...?"
"But, Professor," I argued, "it's all over, isn't it? The tunnel is emptied, and all the Quabos are--"
"The tunnel isn't emptied. It's only half emptied! I'll show you."
He called Stanley; and the three of us went to the break.
"See," the Professor pointed out to us as we approached the jagged hole, "the Quabos only drilled through the top half of their tunnel ending. That means that the tunnel still has about four feet of water in it--enough to accommodate a great many of the monsters. There may be four or five hundred of them left in there; possibly more. We can expect renewed hostilities at any time!"
"But won't it be just a repetition of the first battle?" remonstrated Stanley. "In the end they'll be killed or will drown for lack of water as these first ones did."
The Professor shook his head.
"They're too clever to do that twice. The very fact that they kept half their number in reserve shows that they have some new trick to try. Otherwise they'd all have come at once in one supreme effort."
He paced back and forth.
"They're ingenious, intelligent. They're fighting for their very existence. They must have figured out some way of breathing in air, some way of attacking us on a more even basis in case that first rush went wrong. What can it be?"
"I think you're borrowing trouble before it is necessary--" I began, smiling at his elaborate, scientific pessimism. But I was interrupted by a startled shout from Stanley.
"Professor Martin," he cried, pointing to the tunnel mouth. "Look!"
Like twin snakes crawling up to sun themselves, two tentacles had appeared over the rock rim. They hooked over the edge; and leisurely, with grim surety of invulnerability, the barrel-like head of a Quabo balanced itself on the ledge and glared at us.
For a moment we stared, paralyzed, at the Thing. And, during that moment it squatted there, as undistressed as though the air were its natural element, its gills flapping slowly up and down supplying it with oxygen.
The thing that held us rooted to the spot with fearful amazement was the fantastic device that permitted it to be almost as much at home in air as in water.
Over the great, globular head was set an oval glass shell. This was filled with water. A flexible metal tube hung down from the rear. Evidently it carried a constant stream of fresh water. As we gazed we saw intermittent trickles emerging from the bottom of the crystalline case.
Point for point the creature's equipment was the same as diving equipment used by men, only it was exactly opposite in function. A helmet that enabled a fish to breathe in air, instead of a helmet to allow a man to breathe in water!
Stanley was the first of us to recover from the shock of this spectacle. He faced about and raised his voice in shouts of warning to the resting Zyobites. For other glass encased monsters had appeared beside the first, now.
One by one, in single file like a line of enormous marching insects, they crawled down the wall and humped along on their tentacles--around the ditch and toward us!
The deadly infallibility of that second attack!
The Quabos advanced on us like armored tanks bearing down on defenceless savages. Their glass helmets, in addition to containing water for their breathing, protected them from our knives and axes. We were utterly helpless against them.
They marched in ranks about twenty yards apart, each rank helping the one in front to carry the cumbersome water-hoses which trailed back to the central water supply in the tunnel.
Their movements were slow, weighted down as they were by the great glass helmets, but they were appallingly sure.
We could not even retard their advance, let alone stop it. Here were no suffocating, faltering creatures. Here were beings possessed of their full vigor, each one equal to three of us even as the Professor had conjectured. Their only weak points were their tentacles which trailed outside the glass cases. But these they kept coiled close, so that to reach them and hack at them we had to step within range of their terrific clutches.
The Zyobites fought with the valor of despair added to their inherent noble bravery. Man after man closed with the monstrous, armored Things--only to be seized and crushed by the weaving tentacles.
Occasionally a terrific blow with an ax would crack one of the glass helmets. Then the denuded Quabo would flounder convulsively in the air till it drowned. But there were all too few of these individual victories. The main body of the Quabos, rank on rank, dragging their water-hose behind them, came on with the steadiness of a machine.
Slowly we were driven back down the broad street and toward the palace. As we retreated, old people and children came from the houses and went with us, leaving their dwellings to the mercy of the monsters.
A block from the palace we bunched together and, by sheer mass and ferocity, actually stopped the machinelike advance for a few moments. Miscellaneous weapons had been brought from the houses--sledges, stone benches, anything that might break the Quabos' helmets--and handed to us in silence by the noncombatants.
Somebody tugged at my sleeve. Looking down I saw a little girl. She had dragged a heavy metal bar out to the fray and was trying to get some fighter's attention and give it to him.
I seized the formidable weapon and jumped at the nearest Quabo, a ten-foot giant whose eyes were glinting gigantically at me through the distorting curve of the glass.
Disregarding the clutching tentacles entirely, I swung the bar against the helmet. It cracked. I swung again and it fell in fragments, spilling the gallons of water it had contained.
The tentacles wound vengefully around me, but in a few seconds they relaxed as the thing gasped out its life in the air.
I turned to repeat the process on another if I could, and found myself facing the Queen. Her head was held bravely high, though the violet of her eyes had gone almost black with fear and repulsion of the terrible things we fought.
"Aga!" I cried. "Why art thou here! Go back to the palace at once!"
"I came to fight beside thee," she answered composedly, though her delicate lips quivered. "All is lost, it seems. So shall I die beside thee."
I started to reply, to urge her again to seek the safety of the palace. But by now the deadly advance of the tentacled demons had begun once more.
Fighting vainly, the population of Zyobor was swept into the palace grounds, then into the building itself.
Men, women and children huddled shoulder to shoulder in the cramping quarters. An ironic picture came to me of the crowding masses of Quabos stuffed into the protection of the outer cave, waiting the outcome of the fight being waged by their warriors. Here were we in a similar circumstance, waiting for the battle to be decided. Though there was little doubt in the minds of any of us as to what the outcome would be.
Guards, the strongest men of the city, were stationed with sledges at the doors and windows. The Quabos, able only to enter one at a time, halted a moment and there was a badly needed breathing spell.
"We've got to find some drastic means of defence," said the Professor, "or we won't last another three hours."
"If you asked me, I'd say we couldn't last another three hours anyway," replied Stanley with a shrug. "These fish have out-thought us!"
"Nonsense! There may still be a way--"
"A brace of machine-guns...." I murmured hopefully.
"You might as well wish for a dozen light cannon!" snapped the Professor. "Please try to concentrate, and see if any effective weapon suggests itself to you--something more available at the moment than machine-guns."
In silence the three of us racked our brains for a means of defence. Aga, leaving for a time the task of soothing her more hysterical subjects, came quietly over to us and sat on the bench beside me.
Frankly I could think of nothing. To my mind we were surely doomed. What arms could possibly be contrived at such short notice? What weapon could be called forth to be effective against the thick glass helmets?
But as I glanced at Stanley I saw his face set in a new expression as his thoughts took a turn that suggested possible salvation.
"Glass," he muttered. "Glass. What destroys it? Sharp blows ... certain acids ... variation in temperature ... heat and cold.... That's it! That's it!"
He turned excitedly to the Queen.