Chapter 1

distant past was that day when he had placed himself and this girl in their caskets, safe in their mountain tomb.

* * * * *

Only an instant for these thoughts to form--then his eyes were steady upon the tall savage who had found what he sought in the big metal case. Horab, king of a vanished race, turned now with a heavy scepter in his hand; and its jeweled head flashed brilliantly as he raised it high in air and shouted an echoing command into the room. A white hand was tugging at Garry's shoulder, a soft body clinging close, to turn him where new danger threatened.

The other caskets! He had forgotten them, and he saw the nearer ones alive with struggling forms. A black man-shape, with sullen, animal face and pointed head, came slowly erect and staggered upon the floor. Another--and another! There were scores of the black, naked men who scrambled from the nearer caskets and swayed drunkenly upon their feet.

Garry stood tense, his mind a chaos of half-formed plans. This one brute he might handle, but the whole tribe--that was too large an order. Yet he knew with an unshakable conviction that he would carry this girl from their evil clutches or die in the trying.

Feminine charms had failed to interest Garry in that world outside, but now the message of these soft eyes, the appealing beauty of this lovely face, proud and unafraid despite her fears, the hand so soft and trusting upon his face!--there had something entered into Garry Connell's lonely life that struck deep within him and found a ready response.

He swept one arm about the soft, yielding body beneath its wisp of garment, and he swung her behind him as he set himself to meet the attack. And he flashed her a look that must have carried a message, for the trembling lips were framing a ghost of a smile as her eyes met his.

Garry's thoughts darted to the gun, but his tightly-wrapped pack was in the passage outside. He prayed for a moment's time that he might meet this mob pistol in hand, and he half turned; but no time was given. The leader was shouting orders, his harsh voice resounded in shattering echoes throughout the stone vault, and the horde of blacks surged forward at his command.

* * * * *

A mass of lean bodies, with faces ugly and brutal where sleep-filled eyes opened wide and glaring! They crowded upon him, and Garry met the rush with a rain of straight rights and lefts into the nearest faces. He was carried backward to the wall by the weight of their numbers, but he saw some go down for the count.

The room seemed filled with leaping, shouting men. Their shrill cries echoed in a tumult of discord, and above all Garry heard the hoarse screams of their leader.

There were fists and arms clubbing at his head. He warded them off, then sprang from the wall, leaping outward and sideways, where there was room for free swings of his pounding fists. Another black face went blank under the impact of his blow--a second--and a third!

He was giving ground slowly as the others came on. Then beyond the crowding figures he saw one who held a trident spear high in air. The weapon was poised; the metal points shone in the green light--points that would tear his body to shreds at a single blow.

Garry paused but an instant, then opened his clenched fists to clutch the lean neck of an enemy before him. He whirled the man's body and held it as a shield while he reached vainly to grip at the thrusting spear. Dimly he saw the flash of white and gold where the girl, Luhra, threw her own body upon the armed figure and clung in desperation to the shaft of the deadly weapon.

* * * * *

Garry hung fast to the struggling body, that was his shield; there were other spears now that flashed in the air. He loosed one hand and landed a short jab in the face of a savage whose hands were at his throat. The blow was light, and he was amazed to see the man stagger and fall. There were others who swayed helplessly and stumbled to their knees. Spears rang sharply, clattering upon the stone.... They were falling. The body he held went suddenly limp within his arms and sagged heavily to the floor....

Garry saw the one who had threatened him drop; he took the girl with him as he fell, and his spear flew wildly from his open hand. Garry was alone!--and the enemy was only a tangle of sprawling bodies where the twitching of an outflung arm marked the last sign of life.

He was breathing hard, for some of the enemies' blows had landed, and he staggered as he wiped a trickle of blood from his eyes. No time to figure what this meant, but the blacks were certainly out of it. Beyond the huddled bodies the tall figure of Horab leaped wildly in air as he sprang forward, and in the same instant Garry threw himself between the black menace and the prostrate girl.

He staggered again as he landed from his wild leap, and he called for his last reserve of strength to put power behind the blow that he launched for the snarling face above.

The heavy scepter swung high, and was falling as Garry struck. He saw the blow start; saw the fiery arc the jeweled head made in descending like a mace above his head. Then the face of Horab vanished, and the room was a whirling place of flashing red and yellow before blackness blotted it out....

* * * * *

Garry awoke to blink stupidly at a green light above him. His head was a blinding, throbbing pain that blurred his thoughts.

It cleared slowly. The gleaming figure of a girl was rising from the floor. His aching eyes saw the white of her young body through the dull glow of golden lace. Her eyes came to his, and sharply he realized that this was no dream--this cave whose walls seemed swaying, the face that was staring pitifully at him, and, beyond, in a ghastly green light, the dark silhouette of a lean man who bent his pointed head above a chest.

Connell's mind was a whirl of snarled thoughts and emotions, of puzzled wonder and fighting rage; yet strangely through and above them all was a feeling of pure joy in the message of the eyes in a face that was utterly lovely.

The black figure had opened the chest. Garry saw the luminous green about it shot through with the reflected radiance of many gems. Jewels cascaded brilliantly from the lean black hands as they withdrew a golden cord. Part of some gem-incrusted fabric, it was, that he tore roughly from its rotted fastenings before coming swiftly to the still helpless body of Connell.

Garry's struggles were futile; his hands were tied before him. The shooting pain of a prodding spear brought him from the paralyzing numbness that held him, and he came dizzily to his feet. Again the walls whirled, and he would have fallen headlong but for a lithe, soft body that sprang close to throw white arms about him.

Through blood-shot eyes he saw Luhra, of the land of Zahn, with head held high and flashing eyes as she turned squarely to face the savage black. And he heard the stream of strange sentences that she poured protestingly upon him.

* * * * *

Her message broke off abruptly. Garry's eyes followed hers to watch a savage king, naked but for the tattered remnants of robes that time had eaten. He was reaching, into a casket that had once held kingly raiment--reaching with a lean black hand that brought forth only fragments of purple and crimson cloth that went quickly to dust within his hands.

Garry saw the slitted eyes stare in puzzled wonder at the rotted cloth, then glance sharply and inquiringly about. He saw the black one place a jeweled head-dress of barbaric splendor upon his ugly, pointed head, then rise and cross slowly to the heap of bodies. Spear in hand, he passed on to the serried rows of caskets.

Those nearest were empty, as Garry knew; he had seen the eruption of life from within them. Horab, with a growled word, moved on to the other caskets that stretched out across the room. The ugly head stooped; again the hands reached down, to come back this time with an empty, gleaming skull.

Garry thought once of his pistol, but knew in the same thought that he could never reach it; the spear of Horab would crash through him at the first movement. He dismissed the thought--forgot it--and forgot all else in the fascination of beholding the sagging lips and the scowling stupefaction on the black face of Horab. And slowly there came to his throbbing brain an explanation.

One hundred summers, Luhra had said--Horab had meant to sleep for a hundred years--and the machine that was to waken him had failed to function. Ages beyond computing had passed, and these two only, the black king and the girl, had survived. They had been directly beneath the light; its flooding energy had brought them safely through the dreamless years. But, for the others, it had been different.

Those nearest the light had responded to the vibrating call, but their vitality was gone; their moment of life was short. As for the hundreds who had felt the light but faintly--the skull told the story. They had died as they slept, died thousands of years ago, and their skeletons were all that remained to mock at their king and the frustration of his plans.

* * * * *

But what was the purpose of the long sleep? Luhra's touch and her soundless words supplied the answer.

"Why did he wish this?" her mind said, repeating his question. "Horab's own country was lost; the yellow-ones from across the great water had conquered and overrun it. But Horab had planted the seeds of disease, and the yellow ones must all die in time. Horab is a king and a worker of magic; he is in league with a devil; he learns his magic of him. We of Zahn, all feared the magic of Horab--" She stopped at the quiver of rock beneath their feet.

Garry's mind had cleared, but it was an instant before he knew that the movement was not in his own throbbing head. Then the earth tremor came unmistakably, and his thoughts flashed back to the mass of rock above the mouth of the cave. If more quakes were coming they must get out, and do it at once--

The black hand of King Horab cast the skull vindictively against the wall, and the clatter of its falling fragments mingled with strange oaths from the savage lips. Then he came toward the two and Garry searched his mind desperately for some means of escape.

The trident spear was aimed, and Garry waited for the throw. He felt, more than saw, the flash of light that was Luhra as she sprang for a spear beside the fallen men. An instant and she was before him, tense and poised, a golden Amazon, whose upraised arm and steady eyes checked even Horab in his advance.

She spoke to the savage in sharp, staccato phrases, but Garry got no meaning from the words. There was a quick interchange between them; vehement protest and shaking of his poised spear on the part of Horab. Luhra added a word or two, and she lowered her weapon as Horab did the same.

Her head was bowed as she reached to touch Garry's forehead. He sensed a hopeless sorrow that was so plainly hers, but with it he felt a mingling of another emotion that stirred him to the depths of his being. The slim, white figure straightened, and the dark eyes squarely upon his when she spoke.

"Listen carefully," she said; "it is the last time--"

* * * * *

Garry found himself trembling; he was suddenly breathless with emotion. The racking pain in his head had settled to a dull ache, but his brain was clear, and through it were flashing strange thoughts.

The threat, the wild adventure itself!--they were nothing before the truth that was so plain to him now. He loved this girl! he loved her!--and his whole self responded with an inflow of fresh energy at the thought. A stranger from a strange, lost world!--but what of it?--he loved her!... The message from the lips and fingers of the girl broke in upon the thoughts that were crying for expression.

"You think of me." She smiled with her lips and eyes. "I am glad that you do, my dear one, but it is hopeless.

"Listen: I have promised; Luhra has spoken: I will go with Horab to do as he wills. I will go freely, and he will leave you here unharmed. He promises me this.

"I will go with Horab far across the blue water that surrounds us here. It is an island, as you know, for have you not come here from afar?" Garry broke in with a startled exclamation. An island! Water! He closed his lips upon the denial of her words.

"And you," Luhra continued unheeding, "when we have gone, will return to your own land.

"But, oh, my dear one, remember always I love you. I have read your thoughts, oh bravest and tenderest of men; I loved you from the moment when my eyes opened and found you waiting there. I am telling you now, for I will never see you again." She broke in upon the wild urge of protest that filled his mind.

With an imperious gesture she motioned Horab to discard his spear, and she placed hers beside it on the rocky floor. But she flinched and retreated from the outstretched arms and grasping hands, while Garry Connell struggled in insane frenzy at the cords that bound his wrists.

He felt the lean hands of Horab upon him, and the long arms held him in a crushing grip. And he saw the black face laugh evilly at the watching girl as Horab kicked the spears over beside the casket where she had been.

Garry felt himself raised in air, and he was as helpless as a child in that grasp. An instant later he was thrown heavily, to lie bruised and breathless in the metal box where first he had seen Luhra's face in wide-eyed awakening.

* * * * *

The rasping voice of Horab rose high and shrill. He was shouting triumphantly at the girl, while his hands worked to bind Garry's feet. Luhra's head and shoulders showed above the casket edge as she circled swiftly to approach from the opposite side and reach a trembling hand that would make the contact necessary for thought transference. Her cool touch was upon him; Garry ceased his futile struggle while her words came, brokenly to his mind.

"Horab has tricked us," she cried; "he is leaving you here. He will paralyze you with the devil song of the bell, but not to sleep as I did: it will stop on another note. He says you will be always awake, but helpless--thinking--thinking--always!"

She buried her face in her hands to hide from his gaze the horror that was in her eyes. Garry Connell's straining hands went limp. The terror in the girl's voice struck through his own wild medley of thoughts to make him shudder with realization of the truth.

The threat was real! If Horab left the cave and took Luhra with him, the two would die in the desert. The black savage would never dare to face the strange, new world. And he, Garry, would be here in this cave, in this very coffin, held in a waking death. No one knew he was here; only by chance would the cave be investigated. And when someone finally came!

Garry stared in fascination at the green light. He knew with terrible certainty that whatever help might come would come too late. To lie there hour after hour, for days and then for years--waiting!--always waiting!... And he could never still his thoughts.... He had a sickening realization of the thing they would find. A body!--his body!--and the mind within it utterly insane....

The sound of the shrieking bell was in his ears, and his nerves were trembling in response. He saw long arms above the casket, tearing away the figure of a struggling girl.... And then he knew he was alone....

* * * * *

The sound of the bell rose to the piercing, nerve-shredding scream he had heard before. He must think fast--and act!--but the numbness of brain and muscle was creeping upon him. He tried to call out, but his throat was tight, and would not respond. The echoes died into silence; the vibrations, as before, passed beyond audible range. He was sinking ... sinking....

Dimly he felt the casket shaking beneath him. In some distant corner of his mind he knew that the earthquake shocks had turned. Then he heard with ear-splitting plainness the shrieking discord as the tremor shook the vibrating machine to silence.

The room was quiet; the paralysis left him; and in the instant of his release the clear brain of Garry Connell flashed from chaos to lay before him a full-formed plan.

"Luhra!" he called in the silent room. "Luhra!" But it seemed an age before he heard Horab and his captive returning from the passage. Then the touch of her hand gave him courage to continue.

"Yes?" she whispered; "yes, my dear one?"

He saw the shoulders of the black as he half-raised a spear threateningly toward the girl, then turned to adjust the whirring machine.

"Tell him," shouted Garry, "--tell Horab to shut off that damnable machine!" The shriek of it was rising again to drown his voice. "Tell him his life depends upon it. Tell him to listen to what I say or he will die."

He heard the girl's voice raised in a high-pitched call, and he heard the rasping snarl of Horab in reply. The girl repeated her cry above the echoing clamor of the bell--and the intolerable, rising scream, after a time, was stilled.

Garry experienced one raging moment when he would have given his hope of life for the ability to talk to Horab face to face and in words that could penetrate the black one's brain. But he could not. He must use this girl as an interpreter, and he must give her words to say that would make this ugly beast pause. He must speak as she would speak; put words and sentences into her mouth that would reach the savage superstitions of the other.

He spoke slowly, and stared impressively into the dark, fear-filled eyes in the white face that bent above him. He must make the girl believe.

"Horab works magic," he told her. "Tell Horab that I, too, am a magician--a great magician--a greater one than Horab."

* * * * *

He waited an instant to hear the girl's words and the disdainful laughter from lips in a savage face thrust close to where he lay.

"Horab is truly a magician," said Luhra doubtfully; "he laughs at your magic. Horab's _Tao_ is a strong _Tao_, wicked and powerful."

"His _Tao_?" said Garry, and looked at the girl questioningly. He got the thought in her mind. "Oh, yes--his god, or devil."

He turned his head to stare straight into the grinning face whose wide, thin lips were twisted into a leering snarl. Garry had to summon all his power of will to hold the look that he gave his enemy and to laugh, in his turn, long and contemptuously. Another tremor shook the casket where he lay.

"Tell Horab," he ordered, while his eyes stared steadily into those of the savage king, "--tell Horab my _Tao_ is stronger than his. My _Tao_ is angry because I have been harmed; he is shaking the mountain. He will shake it down on Horab and crush out his life."

He continued to stare while he heard Luhra's voice, high with hope, and he saw a change of expression flicker across the black face, though Horab shouted a vehement reply.

Luhra was speaking to him. "Horab says the earth has shaken before; that it is not your _Tao_ who shakes it. He asks for another sign."

Garry was not surprised. He had fired this shot at random; the tremor itself had suggested it. And now--

"Another sign!" Garry had to fight hard for self-control to keep from shouting the truth to this evil thing--to keep from telling him of the time that had passed, and of the world that was waiting for him. But that would never do: he must play upon this black one's superstitions. Let Horab once leave this cave with that devilish, soundless scream ringing in his ears and he, Garry Connell, was lost. And Luhra!--what hope for her out there?... The black hands were moving impatiently toward the machine....

Garry found himself speaking slowly--short sentences that Luhra quickly repeated. And something within him rose to frame words such as Garry Connell, man of the desert, would never have thought to speak--phrases that best might reach a savage, vicious mind.

* * * * *

He glanced once at the watch on his wrist. He did not feel the torture of the tight gold cord. He was thinking in terms of daylight, and of how much time had passed since he had seen the sun....

"Horab shall have a sign--a terrible sign," he said. "Death waits for Horab in the world outside, my _Tao_ tells me. Horab shall die horribly. I see him choking in the hot sand. His tongue fills his mouth. The hot sun burns, and he is filled with fire. He tries to scream--to call upon his _Tao_--but he makes no sound.... And so shall Horab die."

The girl translated swiftly; the answer was a wild cry of rage from the black. He sprang beside the helpless man and his spear was raised high.

Garry felt the weight of Luhra's body thrown protectingly across him, and looked up to see murder in the savage, slitted eyes. "Tell Horab," he directed sharply, "that if be harms you or me the burning death is his! But--" He waited deliberately after Luhra had spoken, and he saw plainly the flicker of fear in the ugly face. Now was the time.

"Unbind my feet!" he ordered, and he put into his voice all the force and menace he could muster. "Take me to the outer world. Take your spear. If I do not speak truth, kill me there. My _Tao_ will show you a sign; he will fill your heart with fear as it now is filled with evil. But, it may be I can save you. Unbind my feet! Be quick!"

Again he waited while Luhra spoke, and he cursed silently with the agony of waiting. To be playing a part, speaking these absurdly childish things, when what he wanted was his hand upon a gun or in a grip of death about that black throat! Yet he lay as still as if the vibrations of the bell were upon him, and his eyes held unwaveringly upon the savage face, until he felt the fumbling of hands about his feet....

* * * * *

A square-cut portal!--and beyond it a golden sun that shone through mists of purple and rose! Was he too late? Garry pressed forward in what would have been a clumsy run, but for the spear that had prodded him through all the long passage, and that warned now against attempted escape.

The brilliance and heat that struck him when he stepped, out into the open brought Garry in a flash from the world of horror and make-believe into the world he knew. He wanted to shout for sheer joy; but more than all else he wanted to leap at the ugly thing who stood blinking his eyes in the mouth of the cave.

The thought of escape was strong upon him, but the touch of a timid hand showed the folly of that. Luhra was beside him, her filmy lacework shining softly in the sun, to make more lovely the delicate flush beneath. Her eyes, shielded from the sun, were upon him with a look half hopeful, half despairing. No, he must see it through--go on with his play-acting--meet magic with magic. Horab had come out from the cave, and spear in hand he stood commandingly above them on a huge boulder. Yes, the magic must go on.

The harsh voice of the savage ripped out unintelligible words. Luhra translated. "It is changed," she said, "and Horab fears. But the water is there, and there is no burning death.... He says your _Tao_ is weak."

Garry stared with thankful eyes across the blue expanse where a line of white marked ghostly breakers on a distant shore; where hills were reflected in the shimmering blue. But the sun was still above their tops, so he must spar for time--

"My _Tao_ is strong," he said, and went on with whatever fantastic thoughts came into his mind. He was talking against time. He told of the new world his _Tao_ had built, of men harnessing the lightning and flying through the air; of cannon that roared like the thunder and threw death and destruction upon those that the _Tao_ would destroy.... And his eyes watched the slow descent of the dropping sun, while the figure above stirred impatiently and raised his spear.

"A sign!" Luhra was imploring. "He does not believe!"

The golden ball was touching now on a distant, purple peak. The amazing magic of the desert!--its moment had come! Garry indicated as best he could the phantom sea, so real, below.

"My _Tao_ has spoken," he shouted: "watch! The waters shall be dried up; the seas shall become a desert of hot sand; the lands and waters that Horab knows shall be no more! There shall be no food for his stomach nor water for his lips where Horab wanders in torment.... Unless I save him."

* * * * *

He turned to stare at the vast mirage. He knew that the eyes of the others had followed his, and he knew that they saw the first change that crept over the land.

The blue that was so unmistakably a sea was dissolving; it seemed sucked into the sand. And, while yet the hot rays cast their lingering gold over mountain and plain, the seas faded and were gone ... and where they had been in unquestioned reality was only yellow sand that whirled hotly and drifted in the first breath of the coming night....

The towering figure above them stood rigid. Garry had found a sharp edge of rock, and sawed frantically upon it to cut the soft gold of the cords at his wrists. The one above them paid no heed; his eyes were held in horror of this silent death that swept across the world.

The hand that Garry extended was steady and cautious; his arm crept about the body of white and gold to draw the amazed and wondering girl silently into the open cave.

"Follow!" he ordered, and dashed headlong down the darkened way where an automatic was waiting for his eager fingers.

The pack was there, and he tore at it with frenzied hands to grip at the pistol within. And there was also an open chest whose contents glittered in the green light, and whose weight was not too great for him to carry....

He had both chest and gun when he returned. The stumbling falls in his mad rush had not served to allay the hurts of his tortured body, nor still his raging fury. He called to Luhra as he ran--and realized that Luhra was gone. The chest fell forgotten at his feet as he rushed out; he shouted her name and cursed himself for leaving her.

* * * * *

Had the fascination of the outer world drawn her back? Had she trusted too greatly in the power of his Tao to shield her from harm? Connell could not know. He knew only that he saw her struggling in the grip of the long arms where the black one held her on an outthrust rock.

They were a hundred feet away, yet the black face beneath its pointed skull showed plainly its bestial fury as Garry sprang forward. With one motion the tall figure dashed the girl to the stone at his feet and raised his spear. He paused to laugh harshly at the man who rushed toward him--who could never reach him to stop the fatal thrust.

A threat, it might have been, to hold the attacker off, or a murderous intent to end now and forever this one captive's life: Garry did not wait to learn. And the hundred-foot distance that meant a hundred feet of safety to the savage was spanned by a stream of lead from a gun whose stabbing flashes cracked sharply upon the still air. The ringing clatter of a spear that fell among granite stones came thinly to Garry as he saw the black form of Horab, king of another day, spin dizzily from the rock on which he stood.

He had hit him--wounded him at least--and the firing of that wild fusillade might have emptied the magazine! Gary waited for nothing more, but gathered the limp body of the girl within his outstretched arms and carried her stumblingly across the welter of rocks on the boulder-strewn slope. Nor did he stop until he had gained the safety of open ground beyond the marks of the great slide.

* * * * *

The earth was shivering and weaving as he laid her down; a rock crashed sharply in the distance. Garry turned to retrace his steps and leap wildly from rock to rock toward the mouth of the cave in a granite cliff. And the metal chest was in his arms when he returned where Luhra waited.

The ground was alive with sickening motion, he was nauseated with earthquake sickness, but he gave thought only to his gun and the one cartridge that he found in the chamber. He steadied his arm upon a rock to take aim at a figure on a distant slope.

Horab had climbed back upon the rock. A lean figure and black, he was sharply outlined in the last rays of the setting sun; the target was clear beyond the pistol's sights. But the fingers of the grim-faced man refused to tighten upon the trigger.

Savage and cruel--a relic of a bygone age! He stood there, ludicrous and unreal in his stark black nakedness, his frayed robes of crimson whipping to tatters in the breeze. Yet he had forgotten his wounds--Horab was standing upright--and Garry's hand that held the pistol fell loosely at his side. The hate melted from his heart as he watched where Horab drew himself painfully erect.

A barbarous figure was Horab, and evil beyond redemption, yet there were not lacking the attributes of a king in the grotesque form whose head was still held high. The sun made flashing brilliance of the jewels on that distorted head, while he stared with hopeless, savage eyes across the changed world where he could have no part. His _Tao_ had failed him; his enemy had struck him down; and now--

The rock that had been a rest for Garry's arm was swaying, and to his ears came a rumble and groan. Sentinel Mountain, that had watched the ages pass, that had seen the oceans truly change to sand, protested again at this disturbance of its own long sleep.

Garry heard the coming of the masses from above; the crashing din was deadening to his ears. They were safe--and his eyes were upon a savage figure, black and tall, that stared and stared, silently, across a sea of yellow sand. He watched it, clear-cut, motionless--until it vanished beneath the roaring flood of rocks.

* * * * *

And close in his arms there pressed the soft body of a trembling girl who touched his face and whispered: "Your _Tao_, my brave one, is strong. Hold me closely that he may count me as your friend."

His own whispered words, though differing somewhat, were a fervent echo of hers. He saw the rocky masses piled high where the mouth of a cave had been; and "Thank God!" Garry Connell said, "we got out of there in time!"

The casket of jewels lay neglected among the rocks: to-morrow would be time enough to salvage the wealth for which he had risked his life. He swept the girl into his arms, and the sun's last rays made golden splendor of his burden as he carried her across the broken stones.

His ranch showed far below him when he stopped, but the green of date palms had vanished under the last great sweep of rocks. Some few that remained made dark splotches among the shadows that were engulfing the world.

What did it matter? Miramar--"Beautiful Sea!" He laughed grimly at thought of how that sea had served him, but his eyes were tender in his tanned and blood-stained face.

Miramar could be restored. And it would be less lonely now....

ROBOT CHEMIST

A robot chemist with an electric eye, radio brain and magnet hands functioned without human supervision in an improvised laboratory recently before members of the New York Electrical Society.

The automatic chemist performed several experiments. Its work was explained by William C. MacTavish, professor of chemistry at New York University, and was part of a program in which cold light was reproduced, a sample weighing a millionth of a gram analyzed, a photo-electric cell used to control analysis and new scientific apparatus demonstrated.

In his talk on "The Magic of Modern Chemistry," Professor MacTavish demonstrated the separation of para-hydrogen and ortho-hydrogen. In the micro-analysis of a millionth of a gram, Professor MacTavish exhibited in the micro-projector a ball of gold weighing one thousandth of a milligram (one twenty-eight millionth of an ounce), having a value of less than one ten-thousandth of a cent.

The robot chemist was the joint creation of Dr. H. M. Partridge and Professor Ralph H. Muller of the department of chemistry at New York University. In explaining what the automatic chemist can do, Professor MacTavish said:

"The ability of the automatic chemist to control chemical operations is due to its sensitivity to slight variations in color and light intensity. Its working parts are very simple. They consist of a standard light source, in this case an electric light, a photo-electric cell which detects differences in the amount of light impinging on it, a radio tube which amplifies the signal received from the photo-electric cell and which operates the relays controlling the automatic valves.

"Between the electric light and the photo-electric cell is placed a glass vessel holding an alkali that is to be neutralized. Above is a tube from which an acid passes, drop by drop, through an automatic valve, into the alkali. A small amount of chemical indicator added to the alkali maintains a red color in it until it is neutralized. When a sufficient amount of the acid has dropped into the alkali, the red color disappears, indicating complete neutralization.

"When the solution is colored red, an insufficient amount of lights gets through to the photo-electric cell. As the red color gradually diminishes, the amount of light passing through increases, and when the solution is entirely clear the light reaches a critical value which causes the photo-electric cell to pass a signal to the radio tube. This tube operates the relay which closes a valve and shuts off the supply of acid.

"Using a device of this sort to perform such operations around a laboratory will save a great deal of a chemist's time. Its electric eye is about 165 times as sensitive to differences in color as any human eye."

Beyond the Vanishing Point

A COMPLETE NOVELETTE

_By Ray Cummings_