Knowing that the compound of invisibility would dry almost as rapidly as it impregnated the silk, I waited only a brief instant after emptying about half the contents of the vial upon the ball. Then, groping with my fingers, I found the strings that held it into its roughly spherical shape and cut them, after which I shook the silk out as best I could. For the most part it was invisible, but there were one or two spots that the compound had not reached. These I quickly daubed with some of the liquid remaining in my pocket pouch.

So much depended upon the success of my experiment that I almost feared to put it to the test, but it must be tested and there could be only a few xats remaining before the warriors of Haj Osis would burst into the antechamber.

By feel alone I draped the silk over my head so that it fell all about me. Through its thin and delicate meshes I could see objects at close range quite well enough to make my way about. I crossed to Haj Osis and took the blind from his eyes, at the same time stepping quickly back. He looked hurriedly and affrightedly about him.

"Who did that?" he demanded, and then half to himself, "He is gone." For a moment he was silent, rolling his eyes about in all directions, searching every nook and corner of the apartment. Then an expression that was part hope and part relief came to his eyes.

"Quick!" he shouted in a loud voice. "The guard! He has escaped!"

I breathed a sigh of relief-if Haj Osis could not see me, no one could-my plan had succeeded.

I dared not return to the throne-room and make my escape that way along corridors with which I was familiar for I could already hear the rush of feet toward the anteroom door and I was well aware that, although they could not see me, they could feel me and that unquestionably in the rush my mantle of invisibility, or at least a portion of it, would be torn from me, which would indubitably spell my doom.

I ran quickly to the other doorway and unbolted it and as I opened it I looked back at Haj Osis. His eyes were upon the doorway and they were wide with incredulity and horror. For an instant I did not realize the cause and looked quickly behind me to see if I could see what had caused Haj Osis fright and then it dawned upon me and I smiled. He had seen and heard the bolt shot and the door open as though by ghostly hands.

He must have sensed a vague suspicion of the truth, for he turned quickly toward the other door and screamed a warning in a high falsetto voice. "Do not enter," he cried, "until the five xats are up. It is I who commands-Haj Osis, the Jed."

Closing the door after me and still smiling, I hastened along the corridor, searching for a ramp that would carry me to the upper levels of the palace from which I could easily locate the guard room and the hangar where I had left my ship.

The corridor I had entered led directly into the royal apartments.

At first it was difficult to accustom myself to my invisibility and as I suddenly entered an apartment in which there were several people, my first impulse was to turn and flee, but though I had stepped directly into the view of one of the occupants of the room and at a distance of little more than five or six feet without attracting his attention, although his eyes were apparently directly upon me, my confidence was quickly restored. I continued on across the room as nonchalantly as though I had been in my own quarters in Helium.

The royal apartment seemed interminable and though I was constantly seeking a way out of them into one of the main corridors of the palace, I was instead constantly stumbling into places where I did not care to be and where I had no business, sometimes with considerable embarrassment, as when I entered a cozy, private apartment in the women's quarters at a moment when I was convinced they were not expecting strange gentlemen.

I would not turn back, however, for I had no time to lose, and crossing the room I followed another short corridor only to leap from the frying pan into the fire-I had entered the forbidden apartment of the Jeddara herself. It is a good thing for the royal lady that it was I and not Haj Osis who came thus unexpectedly upon her, for her position was most compromising, and from his harness I judged that her good-looking companion was a slave. In disgust I retreated, for there was no other exit from the apartment, and presently I stumbled, entirely by accident, upon one of the main corridors of the palace-a busy corridor filled with slaves, warriors and courtiers, with men, women and children passing to and fro upon whatever business called them, or perhaps seated upon the carved benches that lined the walls.

I was not yet accustomed to my new and surprising state of invisibility. I could see the people about me and it seemed inevitable that I must be seen. For a moment I had hesitated in the doorway that had led me to the corridor. A slave girl, approaching along the corridor, turned suddenly toward the doorway where I stood. She was looking directly at me, yet her gaze appeared to pass entirely through me. For an instant I was filled with consternation, and then, realizing that she was about to collide with me, I stepped quickly to one side. She passed by me, but it was evident that she sensed my presence for she paused and looked quickly about, an expression of surprise in her eyes. Then, to my immense relief, she passed through the doorway. She had not seen me, though doubtless she had heard me as I stepped aside. With a feeling of renewed confidence I now joined the throng in the corridor, threading my way in and out among the people to avoid contact with them and searching diligently all the while for the entrance to a ramp leading upward. This I presently discovered, and it was not long thereafter that I reached the upper level of the palace, where a short search brought me to the guard room at the foot of the ramp leading to the royal hangars.

Idling in the guard room, the warriors then off duty were engaged in various pursuits. Some where cleaning their harness and polishing their metal; two were playing at jetan, while others were rolling tiny numbered spheres at a group of numbered holes-a fascinating game of chance, called yano, which is, I presume, almost as old as Barsoomian civilization. The room was filled with the laughter and oaths of fighting men. How alike are warriors the world over! But for their harness and their metal they might have been a detachment of the palace guard at Helium.

Passing among them I ascended the ramp to the roof where the hangars stood. Two warriors on duty at the top of the ramp almost blocked my further progress. It would be a narrow squeeze to pass between them and I feared detection. As I paused I could not but overhear their conversation.

"I tell you that he was struck from behind," said one. "He never knew what killed him," and I knew that they were talking about the guardsman I had killed.

"But from whence came his assassin?" demanded the other.

"The padwar believes it may have been a fellow member of the guard. There will be an investigation and we shall all be questioned."

"It was not I," said the other. "He was my best friend."

"Nor was it I."

"He had a way with women. Perhaps-"

My attention was distracted and their conversation terminated by the footsteps of a warrior running rapidly up the ramp. My position was now most precarious. The ramp was narrow and the man coming from behind might easily bump into me. I must, therefore, pass the sentries immediately and make my way to the roof. There was just sufficient room between the warrior at my left and the sidewall of the ramp for me to pass through, if he did not step back, and with all the stealth that I could summon I edged myself slowly behind him and you may rest assured that I breathed a sigh of relief when I had passed him.