but a moment since, were wishing that we might undertake.

"Let him go then and slay the black. When he returns we shall still be here to bar his way to the outer world, and thus we shall have rid ourselves of two enemies, nor have incurred the displeasure of the Father of Therns."

As he spoke I could not but note the crafty glint in his evil eyes, and while I saw the apparent logic of his reasoning I felt, subconsciously perhaps, that his words did but veil some sinister intent. The other thern turned toward him in evident surprise, but when Lakor had whispered a few brief words into his ear he, too, drew back and nodded acquiescence to his superior's suggestion.

"Proceed, John Carter," said Lakor; "but know that if Thurid does not lay you low there will be those awaiting your return who will see that you never pass again into the sunlight of the upper world. Go!"

During our conversation Woola had been growling and bristling close to my side. Occasionally he would look up into my face with a low, pleading whine, as though begging for the word that would send him headlong at the bare throats before him. He, too, sensed the villainy behind the smooth words.

Beyond the therns several doorways opened off the guardroom, and toward the one upon the extreme right Lakor motioned.

"That way leads to Thurid," he said.

But when I would have called Woola to follow me there the beast whined and held back, and at last ran quickly to the first opening at the left, where he stood emitting his coughing bark, as though urging me to follow him upon the right way.

I turned a questioning look upon Lakor.

"The brute is seldom wrong," I said, "and while I do not doubt your superior knowledge, Thern, I think that I shall do well to listen to the voice of instinct that is backed by love and loyalty."

As I spoke I smiled grimly that he might know without words that I distrusted him.

"As you will," the fellow replied with a shrug. "In the end it shall be all the same."

I turned and followed Woola into the left-hand passage, and though my back was toward my enemies, my ears were on the alert; yet I heard no sound of pursuit. The passageway was dimly lighted by occasional radium bulbs, the universal lighting medium of Barsoom.

These same lamps may have been doing continuous duty in these subterranean chambers for ages, since they require no attention and are so compounded that they give off but the minutest of their substance in the generation of years of luminosity.

We had proceeded for but a short distance when we commenced to pass the mouths of diverging corridors, but not once did Woola hesitate. It was at the opening to one of these corridors upon my right that I presently heard a sound that spoke more plainly to John Carter, fighting man, than could the words of my mother tongue--it was the clank of metal--the metal of a warrior's harness--and it came from a little distance up the corridor upon my right.

Woola heard it, too, and like a flash he had wheeled and stood facing the threatened danger, his mane all abristle and all his rows of glistening fangs bared by snarling, backdrawn lips. With a gesture I silenced him, and together we drew aside into another corridor a few paces farther on.

Here we waited; nor did we have long to wait, for presently we saw the shadows of two men fall upon the floor of the main corridor athwart the doorway of our hiding place. Very cautiously they were moving now--the accidental clank that had alarmed me was not repeated.

Presently they came opposite our station; nor was I surprised to see that the two were Lakor and his companion of the guardroom.

They walked very softly, and in the right hand of each gleamed a keen long-sword. They halted quite close to the entrance of our retreat, whispering to each other.

"Can it be that we have distanced them already?" said Lakor.