"There are miles of corridors honeycombing the ground beneath the gardens and the temple itself, and there is one passage that leads down to and connects with the lower regions that open on the water shaft that gives passage to Omean.

"If we can reach the submarine undetected we may yet make the sea in which there are many islands where the blacks never go. There we may live for a time, and who knows what may transpire to aid us to escape?"

He had spoken all in a low whisper, evidently fearing spying ears even here, and so I answered him in the same subdued tone.

"Lead back to Shador, my friend," I whispered. "Xodar, the black, is there. We were to attempt our escape together, so I cannot desert him."

"No," said the boy, "one cannot desert a friend. It were better to be recaptured ourselves than that."

Then he commenced groping his way about the floor of the dark chamber searching for the trap that led to the corridors beneath. At length he summoned me by a low, "S-s-t," and I crept toward the sound of his voice to find him kneeling on the brink of an opening in the floor.

"There is a drop here of about ten feet," he whispered. "Hang by your hands and you will alight safely on a level floor of soft sand."

Very quietly I lowered myself from the inky cell above into the inky pit below. So utterly dark was it that we could not see our hands at an inch from our noses. Never, I think, have I known such complete absence of light as existed in the pits of Issus.

For an instant I hung in mid air. There is a strange sensation connected with an experience of that nature which is quite difficult to describe. When the feet tread empty air and the distance below is shrouded in darkness there is a feeling akin to panic at the thought of releasing the hold and taking the plunge into unknown depths.

Although the boy had told me that it was but ten feet to the floor below I experienced the same thrills as though I were hanging above a bottomless pit. Then I released my hold and dropped-four feet to a soft cushion of sand.

The boy followed me.

"Raise me to your shoulders," he said, "and I will replace the trap."

This done he took me by the hand, leading me very slowly, with much feeling about and frequent halts to assure himself that he did not stray into wrong passageways.

Presently we commenced the descent of a very steep incline.

"It will not be long," he said, "before we shall have light. At the lower levels we meet the same strata of phosphorescent rock that illuminates Omean."

Never shall I forget that trip through the pits of Issus. While it was devoid of important incidents yet it was filled for me with a strange charm of excitement and adventure which I think I must have hinged principally on the unguessable antiquity of these long-forgotten corridors. The things which the Stygian darkness hid from my objective eye could not have been half so wonderful as the pictures which my imagination wrought as it conjured to life again the ancient peoples of this dying world and set them once more to the labours, the intrigues, the mysteries and the cruelties which they had practised to make their last stand against the swarming hordes of the dead sea bottoms that had driven them step by step to the uttermost pinnacle of the world where they were now intrenched behind an impenetrable barrier of superstition.

In addition to the green men there had been three principal races upon Barsoom. The blacks, the whites, and a race of yellow men. As the waters of the planet dried and the seas receded, all other resources dwindled until life upon the planet became a constant battle for survival.

The various races had made war upon one another for ages, and the three higher types had easily bested the green savages of the water places of the world, but now that the receding seas necessitated constant abandonment of their fortified cities and forced upon them a more or less nomadic life in which they became separated into smaller communities they soon fell prey to the fierce hordes of green men. The result was a partial amalgamation of the blacks, whites and yellows, the result of which is shown in the present splendid race of red men.

I had always supposed that all traces of the original races had disappeared from the face of Mars, yet within the past four days I had found both whites and blacks in great multitudes. Could it be possible that in some far-off corner of the planet there still existed a remnant of the ancient race of yellow men?

My reveries were broken in upon by a low exclamation from the boy.

"At last, the lighted way," he cried, and looking up I beheld at a long distance before us a dim radiance.

As we advanced the light increased until presently we emerged into well-lighted passageways. From then on our progress was rapid until we came suddenly to the end of a corridor that let directly upon the ledge surrounding the pool of the submarine.

The craft lay at her moorings with uncovered hatch. Raising his finger to his lips and then tapping his sword in a significant manner, the youth crept noiselessly toward the vessel. I was close at his heels.

Silently we dropped to the deserted deck, and on hands and knees crawled toward the hatchway. A stealthy glance below revealed no guard in sight, and so with the quickness and the soundlessness of cats we dropped together into the main cabin of the submarine. Even here was no sign of life. Quickly we covered and secured the hatch.

Then the boy stepped into the pilot house, touched a button and the boat sank amid swirling waters toward the bottom of the shaft. Even then there was no scurrying of feet as we had expected, and while the boy remained to direct the boat I slid from cabin to cabin in futile search for some member of the crew. The craft was entirely deserted. Such good fortune seemed almost unbelievable.

When I returned to the pilot house to report the good news to my companion he handed me a paper.

"This may explain the absence of the crew," he said.

It was a radio-aerial message to the commander of the submarine:

"The slaves have risen. Come with what men you have and those that you can gather on the way. Too late to get aid from Omean. They are massacring all within the amphitheatre. Issus is threatened. Haste.

"ZITHAD"

"Zithad is Dator of the guards of Issus," explained the youth. "We gave them a bad scare-one that they will not soon forget."

"Let us hope that it is but the beginning of the end of Issus," I said.

"Only our first ancestor knows," he replied.

We reached the submarine pool in Omean without incident. Here we debated the wisdom of sinking the craft before leaving her, but finally decided that it would add nothing to our chances for escape. There were plenty of blacks on Omean to thwart us were we apprehended; however many more might come from the temples and gardens of Issus would not in any decrease our chances.

We were now in a quandary as to how to pass the guards who patrolled the island about the pool. At last I hit upon a plan.

"What is the name or title of the officer in charge of these guards?" I asked the boy.

"A fellow named Torith was on duty when we entered this morning," he replied.

"Good. And what is the name of the commander of the submarine?"

"Yersted."

I found a dispatch blank in the cabin and wrote the following order:

"Dator Torith: Return these two slaves at once to Shador.

"YERSTED"

"That will be the simpler way to return," I said, smiling, as I handed the forged order to the boy. "Come, we shall see now how well it works."

"But our swords!" he exclaimed. "What shall we say to explain them?"

"Since we cannot explain them we shall have to leave them behind us," I replied.

"Is it not the extreme of rashness to thus put ourselves again, unarmed, in the power of the First Born?"