An eery scream came suddenly from Durkin's lips; Maget wrung his hands and called for help.

"Come out, Bill, come out," he cried.

Durkin evidently tried to obey, for he turned toward the door. But his knees seemed to give way beneath him, he threw his arm across his eyes as he sank to the ground, crying in agony, incoherent sounds issuing from his lips.

Shriek after shriek the unfortunate man uttered. As Maget made a dash forward to take a chance with death and rescue his friend, Professor Gurlone and his son Kenneth ran up and threw a black cloak over the tramp.

The three entered the shack of death. Maget, not entirely covered, felt his heart give a terrific jump, and he gasped for breath. Durkin was quivering on the floor which was lined with lead.

Round vials stood about the room like a battery of search-lights, and from these emanated the deadly green haze.

But almost before Maget touched his pal, Durkin was dead. Curled up as though sewed together by heavy cords. Durkin lay in a ball, a shaking ma.s.s of burned flesh.

The two Gurlones pushed out ahead of them, and raised their hands.

They had on their black suits and their helmets.

"It is too late to do anything for him now," said Kenneth Gurlone sadly. "He was headstrong. You can see for yourself that the five million dollars takes care of itself. Certain death goes with it if you are unprotected. These lead-cloth suits will keep off the rays for a short time. We always wear them when we are working with the metal, even when we have a lead screen."

"Poor Bill," sobbed Maget. "It's terrible!"

Professor Gurlone shrugged. "It was his own fault. He was a thief and he would not let us stop him. I hope it's been a lesson to you, Maget."

"Yes, I want to help you," said Maget. "If you'll keep me with you, I'll work for you and be straight. Give me a chance."

"Good. Then shake hands on it," said Kenneth, and they clasped hands firmly.

Espinosa appeared from the darkness. "The peons are mad with terror,"

he said morosely. "They cannot be held much longer. They will revolt."

"Well, we must kill the creatures in the cavern: that will quiet them more than anything else," said Professor Gurlone.

"Better close the stone shack," said Kenneth.

But as he spoke, a vast shape, another giant frog, appeared in the entrance of the shaft.

"Get some dynamite and fuses," ordered Professor Gurlone quietly.

"Come on Kenneth, and you, Maget, if you care to risk your life. You need not do so unless you wish to."

Bravely, the older man led the way towards the croaking monster. The ground shook at its approach. It was heading for the bodies of the dead frog and polywog, bent on a search for food. Evidently these vast creatures were forced to prey upon one another for sustenance.

The rifles spoke, and Maget and the professor, in their black suits, protected by the lead-cloth and helmets from the rays, advanced. They poured bullet after bullet into the frog.

Kenneth came running to join them, and Espinosa stood by. Kenneth had dynamite bombs with fuses ready for lighting and throwing. He also brought more ammunition, and the three armed themselves to the teeth.

It was well after midnight when they started into the mine. They knew they must act quickly or retreat, for the bellowing sounded nearer and nearer the surface of the earth.

Each man carried big, powerful flashlights, and the three entered the mine shaft and walked across the seething slugs into the bowels of the earth.

"Stay close together," ordered old Gurlone.

The mine was easy to descend for the first hundred yards. It led in a gentle slope downward. The way, save for a few giant bats and moths, and the big maggots, was clear. The greenish haze, not so bright as that in the death shack, enveloped them, but they needed their flashes to see clearly.

"Slowly, take it easy," counseled old Gurlone.

The mine spread out now, and began a steeper descent. The air was poor, and it was hard to breathe through the mask. Maget, his heart thumping mightily, listened to the roaring within the depths of the mine.

Now the ground seemed to drop away before them. Maget could hear the running of water, the underground river, and every now and then there came an immense splash, as if some great whale had thrown itself about in the water.

A terrifically loud hissing filled their ears, and suddenly, before them, showed an utterly white snake with a head as big as a barrel.

Its white eyes glared sightlessly, but its tongue stuck forth for several feet.

Kenneth Gurlone coolly tossed a lighted bomb at the creature: the explosion shattered their ear-drums, but it also smashed the serpent.

The writhing, wriggling coils, bigger than the body of a horse, slashed about, dangerously near. They picked themselves up, and pushed on, keeping close to the right wall.

A great bat smashed against Maget, and knocked the light out of his hand, but the blow was a glancing one, and he was able to retrieve his light and hurry on.

They were far from the entrance now. The hole which had been broken through by the peons showed before them, and they could see milky water dashing over black rocks.

Pallid eyes looked at them, and they knew they gazed upon another of the giant frogs. They tossed a bomb at the creature, and blew a jagged hole in his back. No sooner had he begun to die than there came a sudden rush of other monsters and a feast began.

"Throw, all together," yelled Kenneth Gurlone.

Into the vast ma.s.s of creatures, who crowded one another in the river for their share of the spoils, they threw bomb after bomb. The dynamite deafened them, and acrid fumes choked them, but they fired their rifles at the prodigious animals and there, in the big river cavern, was a seething ma.s.s of horrible life, dying in agony.

The bellowings and hissings sounded louder, so loud that the earth shook as if actuated by a mighty earthquake.

Maget gripped Kenneth Gurlone's arm. "My bombs are gone," he shouted.

He had but a few rounds of ammunition left, and still more of the giant reptiles appeared. A centipede with its creeping, horrible legs topped the ma.s.s of squirming matter; they could see the terrific sting of the creature, so deadly when but a fraction of an inch long, and which was now at least a foot, armed with poison.

There came the rush of more bats and moths, a rush that threw the three men off their feet.

"We must have opened the hole more with our bombs," shrieked old Gurlone. "The dead bodies attract the other creatures, more and more of them are coming. It is impossible; we cannot deal with them all."

The vast gobbling of the great animals in the river below them was so prodigious they could not grasp it. It seemed it must be optical illusion. In a few moments, the dead had been eaten, swallowed whole, and fights were progressing between the victors.

They tossed the rest of their bombs, fired the remaining ammunition, and as they prepared to retreat, several of the big creatures slopped over and started up the river bank into the mine shaft.

They ran for their lives, the three. Madly, with the earth shaking behind them as they were pursued by a hopping monster of a beetle with immense mandibles reaching out at them, they dashed for the open air.