not do?" But a light laugh broke from her lips and spoiled her bluff.

"There are two reasons," replied her companion seriously. "First, because we both believe that Hekalu Selba is dangerous; second—because I love you." He leaned closer toward her with the light of eagerness in his eyes. "Oh, I know I'm crude, Jan," he said passionately. "I'm just a clumsy engineer, not a poet or ladies' man. What I'm trying to say to you must seem awfully trite, but anyway, I want you with me always."

"You mean—?"

He nodded.

"All right, Austin," she said quietly, looking straight into his eyes.

His arms crept around her, and now he drew her gently to him.

Some moments later, in the nearby pergola, the door which led to the rooms below opened, and an ancient negro clad in gaudy pajamas and bathrobe peered out into the garden. He saw the pair and recognized the girl. A happy grin came over his wrinkled black face. "Well, if dat ain't a mos' pretty sight to look at," he muttered. "My baby done come back at las', and dat sho' am a han'some boy she got dar!" He turned, and leaving the door open and the light burning on the stair, descended. Very softly and wistfully he was crooning an old darky love song.

It was an hour later before Shelby's craft whirred up into the moon-bathed night over the winking lights of the city. And at the same time the big-eyed Sadu moth which had been crouching in the cypress tree, rose on its velvety wings and sped away, as though some urgent mission had suddenly claimed its attention.

CHAPTER III

Hekki's Proposal

When Shelby reached his apartment, he immediately donned his laboratory smock and set to work. But he had scarcely finished mounting a tiny coil of wire within the hand-grip of his weapon, when the view-phone bell rang insistently.

The inventor pulled off his smock and threw it over the materials on his work bench, so that the person at the other end of the view-phone connection, whoever it was, would not be able to see them. Then he snapped the television and audio switches. The mists in the view-plate cleared, and there before him, as real as though he were actually in the room, sat Hekalu Selba. The Martian's eyes gleamed with suppressed excitement.

"Mr. Shelby," he was saying, "it may seem strange that I should be calling you so soon, but I have something simply colossal to talk over with you. You must come up to my place immediately! I realize that you may be very busy, but this is important!" And he added, "It's nothing to discuss over the view-phone. Will you come?—please!"

Shelby was about to make a cold reply, but he checked himself. An intense curiosity gripped him.

"All right, Akar Hekalu," he said. "I'll be there." The switches clicked.

Hastily Austin changed to his street clothes, and then gathered together the material for his weapon and placed them in the wall safe. Only one thing he selected from the jumble of apparatus—a tiny pinkish crystal, without which it was impossible to produce the Atomic Ray. This he secreted in a hollow button on his sleeve.

For a long moment he stared at his automatic, which lay on his work bench. "Better take you along," he muttered at length, "—may need you."

A wizened black-clad man whom Shelby surmised was the slave Alka, met him at the entrance on the landing platform of a quaint Martian tower atop a huge apartment building, and ushered him into an elevator. He was whisked rapidly downward, and emerged into the central light-well which pierced the structure from top to bottom. The barbaric tapestries upon the walls of this tall cylindrical chamber, the tiling of the floor, which consisted of squares and circles and spear points of various colored stone, fitted artfully together, giving an effect of pleasant disorder. And most of all, the smell of strange incense in the air, told Shelby that he had dropped into a little bit of old Pagar or Mars. Evidently the Prince of Selba was master of the entire tower, which, in itself, was by no means small.

Alka led the way down a short passage, and admitted the Earthman to a large sumptuously furnished room, one end of which was softly illuminated by a quaintly beautiful floor lamp. The farther end of the room was in complete darkness. The Pagarian architects had made it imitate the interior of a natural cavern, for where the light approached the gloom, two glassy stalactites gleamed with a scintillant elfin light.

Shelby had but a moment to take note of his surroundings—the dark hangings woven with silver threads, the embossed shield and spear of an ancient Martian warrior mounted on the wall—before Hekalu entered. The young man saw at once that the noble had lost his air of bored languor which he had noticed about him at the time of their first meeting. His eyes flashed with excitement and his movements were quick and cat-like.

"I see that you have come quickly, Mr. Shelby," said the Martian, "and I am glad. Won't you sit down?"

With scarcely a pause he continued: "I have great wealth, my friend, and while your means do not seem to be small, I believe that it would be very convenient to you to have them supplemented. Suppose I gave you say, ten times as many jewels as are in the tray over on that stand?" Shelby looked in the direction the Martian indicated. He saw a flat shallow container of considerable size. At its center squatted a repulsive thing about eight inches high, carved from a clear crystalline substance from which there flashed countless points of icy, wicked fire—a huge diamond!

Heaped around it were hundreds of magnificent red tabalti, most prized of all gems. An expert appraiser had recently told Shelby that in two worlds only thirteen of them were known to exist. And now he was being offered all these stones by one who hinted that he was willing to give him ten times as many—an utterly staggering fortune!

Hekalu's words fairly dumbfounded Shelby, but they grated upon his sense of pride as well. Nevertheless, his face gave no hint of what passed through his mind. An angry reply, he decided, was out of place.

"Naturally, Akar Hekalu, you want something in return for your amazing generosity," he said coolly. "Of course, I could not accept your offer under any other circumstances."

The Martian nodded. "I have it from a reliable source, Mr. Shelby, that you are the inventor of a terrible weapon—an atomic ray which might be dangerous in the hands of unworthy persons. Turn the weapon over to me as well as all information concerning its operation and construction, and promise to say not a word more about the weapon to anyone, and I will give you the jewels at once."

A flash of surprise passed across Shelby's face but he quickly masked it. So this was it! But how was it that the noble had learned of his invention? Could it be that Janice Darell was playing a double hand?—his Jan. He dismissed the idea as preposterous and utterly disloyal.

The Earthman rose to his feet and addressed the Martian coldly. "If I have such a device I believe that I can place it in better hands than yours."

Hekalu Selba's face gave no hint of anger; in fact he seemed at the point of laughing. "You have done as I expected you would. Your refusal shows me how patriotic you are and gratifies me very much, Mr. Shelby," he said blandly. "You are as a man of Earth should be. However, there is another side to the question. I have certain plans and to have you at large might endanger their fulfillment. Therefore I must ask you to accompany me on a little trip. That weapon of yours will be well taken care of. Now, kindly raise your hands high above your head." The Martian was pointing a bejeweled automatic straight at the chest of his visitor. "You are being covered from two other points in this room so try not to cause any misunderstanding," he added.

Shelby saw the wisdom of obeying the order for he felt quite certain that Hekalu Selba and his