little larger than kennels. At the six-foot wall that surrounded this plateau he paused. "Would you like to look over the wall?" he asked.

For the space of a breath we hesitated. Was this a trap? Through my mind flashed the words of the man who had guided us to Fraser. "You are two thousand feet above the earth," he had said. Was that true? And if it were, might not Fraser push us over the wall? But instantly logic came to my rescue. Fraser had brought us here, and he could have brought us for but one thing: to question us. Would he be apt to do us harm before those questions were asked? And besides, would Fraser's brilliantly subtle mind stoop so low as to destroy enemies by pushing them over a wall?

"Thank you," we murmured simultaneously. "This whole achievement is of tremendous interest to us," Foulet added.

Fraser chuckled. "It will be of greater interest—later," he said, and his blank, glittering eyes rested on first one of us, then another with a cold, satisfied gleam. Then he lifted his hand and opened a square door in the wall about the size of a port-hole. To my surprise the little door swung back as lightly as a feather and made scarcely a sound as it slammed against the wall itself. Again Fraser answered my unspoken thought.

"It has only substance," he said with his vain smirk. "No weight whatever. This entire platform together with its huts is lighter than air. If I should tear loose this little door it would float out of my hands instantly and go straight up to the stars. The substance—I have called it Fleotite—is not only lighter than air but lighter than ether."

"But we are not floating," said Brice; "we are stationary. Is the lightness of your Fleotite counteracted by the weight of the men and machines?"

Fraser shook his head. "Not entirely," he said. "But first look through this little window. Then I will explain."

Eagerly we pressed forward. Our danger was almost forgotten in our interest. This was amazing—stupendous! Together, shoulder to shoulder, we gazed through the aperture. We were suspended in space! Above us shone the blue-black Arabian night, and beneath us—far, far beneath—lay the sands of the desert looking rosy and warm in that same dull red glare of light that, to a fainter degree, gave us the effect of afterglow. But we were not floating; we were anchored as securely as a ship riding in a calm harbor.

We turned back to Fraser, amazed, awed, bursting with questions. Madman he might be, but he had wrought a miracle.

"I will explain," he said and his eyes gleamed with pride. "Of course you know of my tremendous discoveries connected with the power of light. At any rate, five years ago, the scientific world on earth thought they were tremendous. In reality that was nothing to my amazing strides in the past three years. There is nothing that cannot be done with light! Nothing!" For the first time Fraser's eyes became alive. They were illumined. His whole body seemed to radiate light and fire and genius. We listened, fascinated.

"Take, for instance," he continued eagerly, "that ray with which I drew you and your plane to me. That ray is the pure power of magnetism. At full strength it will draw anything to it instantly. Fortunately the power can be regulated: I can switch a lever in my laboratory and draw things to me, via the ray, at any speed I wish—one hundred, two hundred, a thousand miles an hour."

"How far can you throw the ray?" asked Foulet, and I knew he was thinking of that glider that rose from the roof-tops of Constantinople. Fraser also knew he was thinking of that.

"I did not draw the glider," he said quietly. "The airplane I sent did that. My airplanes carry batteries of this ray. In the beginning I found gliders to be more practical for my purposes than airplanes. For one thing they were silent. My only problem was that of getting them off the ground. Once they were in the air I could manage everything. It was this problem that inspired this discovery and perfection of the ray. But, you asked how far I can throw the ray? This main lamp, that I operate myself from here, is effective at two hundred miles. At one hundred miles it enjoys its full power."

"And you can draw anything to you," asked Brice, "within the radius of the magnetic ray?"

"Anything in the air," answered Fraser. "But of course I must use caution. Great caution. If I drew planes to me indiscriminately I would draw attention to myself; my secret and my location here would leak out. No. That must not be. So the only planes I bring are my own—and yours." He paused and his black eyes, again glassy, swept over us. "It is a compliment I pay you," he said finally. "You have become too troublesome. You know too much. Sooner or later the time would come when you would combine your forces. That would be a nuisance. So I decided to bring you here."

"Suppose," asked Foulet curiously, "we hadn't fallen into your trap? Suppose we had turned back before reaching the point where your ray is effective?"

Fraser shook his head and that smug, offensive smile appeared again. "You were trapped from the beginning, though you didn't know it," he said. "The plane you were following was equipped with batteries of the ray which, while not as powerful as the lamp I have here, were still powerful enough to hold you to the course we choose you to run. But enough of the ray," he added impatiently. "There are one or two other things I want to explain and then—" he paused and the pause, somehow, was alive with menace. What was he going to do after he had finished treating us as honored guests? For the third time he answered my unspoken question. His eyes narrowed till they were black, glittering slits. His voice, as he leaned toward us, was no more than a hissing whisper.

"Slaves!" he said, and his lips twisted. "How will you like to be slaves of Mad Algy Fraser?" He laughed—a chuckle that started in his throat and rose and rose till it seemed to shatter my ear-drums. I felt my teeth grinding together and my nails bit my palms in my effort to control my nerves against the strain of that maniacal glee. Suddenly he sobered. His laugh died instantly like a radio that had been snapped off. "Listen and I will tell you. I will tell you everything because it is necessary for you to know so that you may work for me intelligently and you will remember better and be of greater use to me if I tell you now while you are yet—sane!"

"Sane!" The exclamation sprang from the three of us simultaneously. I felt a cold chill start between my shoulder blades. For an instant my breath choked in my throat. My heart paused—and then raced. What did he mean? What was he going to do to us? What scheme had he evolved in his crazed brain?

"I have perfected a serum"—his tone was professional, cold; he might have been talking to a class in a lecture room—"a serum that robs the patient of every vestige of human emotion—and therefore sanity. All his intellect, his memories, however, remain, to serve him in carrying out my orders. He loses all his will to live and resist, and becomes nothing but an automaton, whose complete mental equipment is at my command."

There was silence. His glassy black eyes, blank and soulless, swept over us. His mouth curled in that smug, complacent smile. He had us with our shoulders to the floor. He knew it—and he knew we knew it. There was no possible way we could escape. We were two thousand feet above the earth. Our plane wouldn't get a quarter of a mile before the magnetic ray would bring it back. Parachute? Even supposing we could get parachutes where would we go? Drop two thousand feet into the middle of the Arabian Desert?

My brain raced. Never before had I been in such a tight place. And soon—if Fraser had his way—I wouldn't even have a mind to think with! I felt choked, stifled. Was there no way out? It seemed to me that a blanket—a soft, terrible blanket