there, thus causing droughts and rainfall at will. But now, as with the case of most of the other machines, Omega needed it no longer. He kept it because it linked him with the joy of the past. Besides, there was the mind-control appliance by whose aid man's mind might visit other worlds. This was done through the development of the subconscious and the discipline of the will. But Omega was weary of these pilgrimages, because his body could not perform those far-off flights. As time went on he realized that the earth was his natural home. Even the earth's neighbors, dead and dying, offered him no haven.

Yes, Omega and Thalma had garnered the gist of the world's treasures before commencing this last trek. Gold and precious stones were common objects to them, because for countless ages man had made them at will, but around those they had brought clustered sacred memories of loved ones gone before. The biological machine in the chemical laboratory of the ship—the machine that brought forth life from nature's bountiful storehouse—was of little use now that both atmosphere and moisture were nearly gone. Yet Omega cherished this machine, and aside from its associations with the past, it held for him a fascination that he could not understand.

Having set the Mirror and other mechanical servants in position, Omega and Thalma returned to the ship, and slept throughout the day, for with the descending sun they must again go forth to hunt that scaly demon which had taken possession of the earth's last water.

The night was moonless, but the bright starlight brought all objects into plain relief against the dark rocks. Taking position on the slope several rods above the beach, Omega and Thalma watched the lake eagerly, but nothing disturbed its mirror-like surface. As on the preceding night the awful silence appalled them—even though they were accustomed to the vast solitude. It was so calm and still, so full of death and mystery, that it seemed they must cry out in the agony of their emotions. As the very silence was crushing their spirits so the knowledge that only one form of life on earth stood between them and the water to which their last hope clung, was maddening. How they longed to battle the hideous monster! But the hours dragged on with nothing to disturb the dead, heart-breaking silence. At last the Great Dipper had swung so far around that dawn appeared. Yet there had been not a ripple on the lake. Omega concluded that his guess was wrong—the beast did not leave the water at night to search for food. Perhaps it had learned the futility of such a search in a dead, dust-covered world.

Wearied by their long and fruitless vigil they must have dozed, for suddenly Omega, who sat but a yard or two from Thalma, was aroused by a padded footfall and the exhalations of a noisome breath. Looking up he was horrified to see the monster towering above him, its head swaying gently to and fro, as its great, awkward feet sent it lunging forward and backward for many feet, its spotted, scale-covered body trailed over the rocks. By suddenly rounding the shoulder of the rock, sheltering Omega and Thalma, its head held high, it seemed not to have seen the two humans, for its terrible unblinking eyes were fixed ahead on the water. However, Omega, paralyzed with fear and astonishment, and being directly in the beast's path, believed that his hour had come. This was to be the end of all his plans—to be crushed by the enormous weight of the monster which challenged his right to live. But in that tense moment when he thought that it was all over, the lithe form of Thalma reached his side and in a frenzy of terror pulled him away. But even then the sloping belly of the onrushing beast tore him from her frail hands and dashed him against the rock.

While he lay there stunned and unable to move, Thalma discharged her weapon at the monster. Three times she fired in quick succession but the shots went wild, and in another moment the great brute struck the water with a resounding splash and disappeared from view. For a few minutes a trail of surface bubbles marked its rapid course toward the lake's center, then all was motionless and still as before.

"Are you hurt, Omega?" Thalma cried anxiously, kneeling by his side.

"Just shaken up a bit," he returned, sitting up with an effort. "Great hunters are we," he went on with a laugh. "We almost allowed the game to catch the hunters! Well, let's go back to the ship. We'll get him next time."

But their narrow escape had shaken their nerve. All day long they remained safely in the ship and kept their guns trained on the lake hoping that the beast would show himself. How or when it had left the lake they could not surmise, but that it was more formidable than they had thought now seemed certain, and Omega concluded to bring science to his aid. In this way he was sure that he would soon exterminate the monster.

So the next day he lay a cable carrying a high voltage all around the lake and connected it with traps of various designs both in the water and on the land. No more would they risk their lives hunting the beast in the open after nightfall.

The hot, still days that followed were anxious ones for these last children of life. Not a trap was sprung. The beast did not drag his slimy body and tail across the heavily charged cable. The last of his kind, fighting the last battle of existence, it seemed that nature had endowed him with uncanny cunning. There was the life-giving water for whose possession no human kind challenged them, but this enemy was more terrible than any man, savage or civilized whom the earth had ever known.

During these anxious, watchful days Omega and Thalma went often to the Mirror and gazed into it in search of vapor clouds. And more than once those gossamer-like formations appeared over different parts of the world to gladden their hearts only to fade away before their vision. The reflections of those embryo clouds became less frequent as the days wore on. Omega and Thalma knew that they had no right to hope for the return of water vapor. Their instruments, so finely attuned as to appear endowed with intelligence, the records of the past and their own common sense told them that. But nature and life in the upper reaches of the air were dying as hard as their own hope. They knew that the aerial manifestations they witnessed were but symptoms of the death struggle. And yet a real cloud, dark and pregnant with moisture, suddenly appeared in the Mirror. Consulting the chart they saw that it was hovering over a great land of plain and mountains which formerly had been a part of the United States of America.

"We will go and examine this gift from heaven," said Omega. "It moves over a once beautiful land, which the voices of history tell us, harbored a race of the free millions of years ago."

"Yes, we will go," agreed Thalma. "It may be after all that Alpha will first see the light far from this dreadful hollow and—and—that monster out there in the lake."

Omega hung his head. Well he knew that the presence of the monster was slowly killing his beloved. She complained not, but her dreams were disturbed with frightful visions, and often Omega awakened to find her at a window staring out over the lake with terror-stricken eyes.

This new cloud was thousands of miles to the east but with fond anticipations they entered the ship and plunged toward it. But although they reached the spot in one hour, the last remnant of vapor dissolved before their eyes, and they turned sadly homeward, once more beaten by the inexorable decrees of fate.

So having decided at last that this deep valley must remain their home forever, Omega looked about for a suitable building site, for although the ship was safe and comfortable they longed for a home on the earth. But the ever present menace of the sea-monster saddened them and filled them with misgivings, despite the fact that Omega could guard the cottage electrically. But