Not possessing sufficient technical knowledge to enable me to build one of the new type motors, I had to content myself with one of the old types of much less efficiency.

At last the work was done. We had a ship that would accommodate four with ease and it was uncanny to realize this fact and yet, at the same time, be unable to see anything but the tiny eyes of the periscope when the covers were lowered over the ports, and even the eye of the periscope was invisible unless it was turned in the direction of the observer.

As the work neared completion I had noticed that Phor Tak's manner became more marked by nervousness and irritability. He found fault with everything and on several occasions he almost stopped the work upon the ship.

Now, at last, we were ready to sail. The ship was stocked with ammunition, water and provisions, and at the last minute I installed a destination control compass for which I was afterward to be devoutly thankful.

When I suggested immediate departure, however, Phor Tak demurred, but would give me no reason for his objection.

Presently, however, I lost patience and told the old man that we were going anyway whether he liked it or not.

He did not fly into a rage as I had expected, but laughed instead, and there was something in the laugh that seemed more terrible than anger.

"You think I am a fool," he said, "and that I will let you go and carry my secrets to Tul Axtar, but you are mistaken."

"So are you," I snapped. "You are mistaken in thinking that we would betray you and you are also mistaken in thinking that you can prevent our departure."

"Heigh-oo!" he cackled. "I do not need to prevent your departure, but I can prevent your arrival at Jahar or elsewhere. I have not been idle while you worked upon this ship. I have constructed a full-size Flying Death. It is attuned to search out this ship. If you depart against my wishes, it will follow and destroy you. Heigh-oo! What do you think of that?"

"I think that you are an old fool," I cried in exasperation. "You have the opportunity to enlist the loyal aid of two honorable warriors and yet you choose to turn them into enemies."

"Enemies who cannot harm me," he reminded me. "I hold your lives in the hollow of my hand. Well have you concealed your thoughts from me, but not quite well enough. I have read enough of them to know that you think me mad and I have also received the impression that you would stop at nothing to prevent me from using my power against Helium. I have no doubt but that you will help me against Jahar, and against Tjanath, too, perhaps, but Helium, the mightiest and proudest empire of Barsoom, is my real goal. Helium shall proclaim me Jeddak of Jeddaks if I have to wreck a world to accomplish my design."

"Then all our work has been for nothing?" I demanded. "We are not going to use the ship we have constructed?"

"We may use it," he said, "but under my terms."

"And what are they?" I asked.

"You may go alone to Jahar, but I shall keep Nur An here as hostage. If you betray me, he dies."

There was no moving him; no amount of argument could alter his determination. I tried to convince him that one man could accomplish little, that, in fact, he might not be able to accomplish anything, but he was adamant-I should go alone or not at all.

Eleven. "LET THE FIRE BE HOT!"

As I arose that night into the starlit splendor of a Barsoomian night, the white castle of Phor Tak lay a lovely gem below me bathed in the soft light of Thuria. I was alone; Nur An remained behind the hostage of the mad scientist. Because of him I must return to Jhama. Nur An had exacted no promise from me, but he knew that I would return.

Twenty-five hundred haads to the east lay Jahar and Sanoma Tora. Fifteen hundred haads to the southwest were Tjanath and Tavia. I turned the nose of my flier toward the goal of duty, toward the woman I loved, and, with throttle wide, my invisible craft sped toward distant Jahar.

But my thoughts I could not control. Despite my every effort to keep them concentrated upon the purpose of my adventure, they persisted in wandering to a prison tower, to a tousled head of refractory hair, to a rounded shoulder that had once pressed mine. I shook myself to be rid of the vision as I sped through the night, but it constantly returned and in its wake came harrowing thoughts of the fate that might have overtaken Tavia during my absence.

I set my destination control compass upon Jahar, the exact position of which I had obtained from Phor Tak, and thus relieved of the necessity of constantly remaining at the controls, I busied myself about the interior of the ship. I looked to the ammunition of the disintegrating ray rifles and rearranged it to suit my own ideas.

Phor Tak had equipped me with three types of rays; one would disintegrate metal, another would disintegrate wood and the third would disintegrate human flesh. I had also brought along something which Phor Tak had refused me when I had asked him for it. I pressed the pocket pouch in which I had placed it to make sure that I still had the vial, the contents of which I imagined might prove of inestimable value to me.

I raised all the port shutters and adjusted the ventilators, for at best the interior of this strange ship seemed close and stuffy to one who was accustomed to the open deck of the fast scout fliers of Helium. Then I spread my sleeping silks and furs and settled myself down to rest, knowing that when I arrived at Jahar my destination control compass would stop the ship and an alarm would awaken me if I still slept, but sleep would not come. I thought of Sanoma Tora. I visualized her cold and stately beauty, but always her haughty eyes dissolved into the eyes of Tavia, sparkling with the joy of life, soft with the light of friendship.

I was far from Jhama when at last I sprang determinedly from my sleeping silks and furs, and going to the controls, I cut off the destination control compass and with a single, swift turn swung the nose of the flier toward Tjanath.

The die was cast. I felt that I should experience remorse and self loathing, but I experienced neither. I joyed in the thought that I was rushing to the service of a friend and I knew in the most innermost recesses of my heart that of the two, Tavia had more claim upon my friendship than had Sanoma Tora, from, whom I had received at best only scant courtesy.

I did not again try to sleep. I did not feel like sleeping; instead I remained at the controls and watched the desolate landscape as it rushed forward to pass beneath me. With the coming of dawn I saw Tjanath directly ahead of me and as I approached the city it was difficult for me to realize that I could do so with utter impunity and that my ship with its closed ports was entirely invisible. Moving slowly now, I circled above the palace of Haj Osis. Those portions of the palace that were topped by flat roofs revealed sleepy guardsmen. At the main hangar a single guardsman watched.

I floated above the east tower; beneath me, cuddled in her sleeping silks and furs, I could picture Tavia. How surprised she would he could she know that I hovered thus close above her.

Dropping lower I circled the tower, coming to a stop finally opposite the windows of the room in which Tavia had been confined. I maneuvered the ship to bring one of the ports opposite the window and close enough to give me a view of the interior of the room. But though I remained there for some time, I could see no one and at last I became convinced that Tavia had been removed to other quarters. I was disappointed for this must necessarily greatly complicate my plans for rescue. I had foreseen but little difficulty in transferring Tavia by night through the tower window to the flier; now I must make my plans all anew. Everything hinged, of course, upon my ability to locate Tavia. To do that it was evident that I must enter the palace. The moment that I quitted the invisibility of my flier, I should be menaced by the greatest danger at every turn, and, clothed as I was in home-made harness fashioned by the hands of the slaves of Phor Tak, I should arouse the active suspicion of the first person who laid eyes upon me.