Now Carter shoved the stone with all his tremendous strength. Inch by inch he moved it until finally there was room for him to squeeze his body through.

He was still in utter darkness, but his gripping fingers revealed to him that he was in a corridor between two walls. Perhaps this was the way out of his prison!

Carefully he shoved the stone back into position, leaving no trace of his disappearance from the room. The corridor in which he found himself was so low that he was forced to crawl on hands and knees. The low corridor had the stench of age, as if it had been unused for a long time.

Gradually the tunnel sloped more and more downward. Many little side-passages branched off from the main tunnel. There was no light, no noise. Only a faint, pungent odor beginning to fill the air.

Now it was growing lighter. The earthman realized that he must be in the subterranean caverns of the palace. The dim light was caused by the phosphorescent radium glow that is used on all Mars for radiation.

The source of this faint light the earthman suddenly discovered. It was shining through a cleft in the wall ahead. Pushing aside another loose stone, John Carter crawled forth into a chamber. He drew in his breath sharply.

Facing him was a warrior with drawn sword, the point of which was almost touching the breast of the earthman! John Carter leaped back with the speed of lightning, whipped out his own sword and struck at the other's weapon.

The arm of the red man fell from his body to the floor where it dissolved into dust. The ancient sword clattered on the cobblestones.

Carter could see now that the warrior had been leaning against the wall, balanced there precariously for ages, his sword arm extending in front of him just as it had stiffened long ago in death. The loss of the arm overbalanced the torso which toppled to the floor and there dissolved into a heap of ash-like dust!

In an adjoining chamber there were a score of women, beautiful girls, chained together by collars of gold around their necks. They sat at a table where they had been eating, and the food was still before them. They had been the prisoners, the slaves of the rulers of the long-dead city. The dry, motionless air combined with some gaseous secretion from the walls and dungeons had preserved their beauty through the ages.

The earthman had traversed some little distance down a musty corridor when he became aware of something scraping behind him. Whirling into a side corridor he looked back. Gleaming eyes were coming toward him. They followed him as he backed into the tunnel.

Now again came the scraping, repeated this time farther ahead in the tunnel. Other eyes shone ahead of him.

John Carter ran forward, his sword-point extended. The eyes ahead retreated, but those in back of him started to close.

It was very dark now, but far ahead the earthman could see a faint gleam of light filtering into the tunnel.

He ran toward the light. Fighting the things where he could see them would be a lot easier than stumbling around in a dark corridor.

Carter entered the room and in the dim light came face to face with the creature whose eyes he had seen ahead of him in the tunnel It was a species of the huge three-legged Martian rat!

Its yellow fangs were bared hideously in a vicious snarl, as it backed slowly away from Carter to the far end of the small room.

Now behind him came the other rat, and together the two beasts started to close in upon the earthman.

Carter smiled grimly as he gripped his sword. "I am the proverbial cornered rat now," he muttered as he swung his blade at the nearest creature.

It ducked the blow and scurried toward him.

But the earthman's sword was ready. The charging rat lunged full upon the waiting sword-point.

The momentum of the beast carried Carter back five feet; but he still retained a hold on his sword, the point of which had plunged through the animal's single shoulder and pierced its wild heart.

When Carter had jerked free his sword and turned to meet his other antagonist an exclamation of dismay escaped his lips. The room was half filled with rats!

The creatures had entered through another opening and had formed a circle around him, waiting to attack.

For half an hour, Carter battled furiously for his life in the lonely dungeon beneath the palace in the ancient city of Korvas.

The carcasses of the dead rats were piled high around him, but still they came and eventually they overpowered him by their very numbers.

John Carter went down by a terrific blow to his head from a snake-like tail.

He was half stunned, but he still clung tenaciously to his sword as he felt himself seized by the arms and dragged away into the darkness of an adjoining tunnel.

FOUR THE CITY OF RATS

John Carter recovered fully when he was dragged through a pool of muddy water. He heard the rats greedily drinking, saw their green eyes gleaming in the darkness. The smell of freshly dug earth reached his nostrils and he realized that he was in a burrow far under the subterranean vaults of the palace.

Several rats on either side of him had hold of his arms by their forepaws as they dragged him along. It was very uncomfortable, and he wondered how much longer the journey would last.

Nor had he long to wait.