“Long, complicated and heavily annotated by Carlin”, he said. “It will take us the rest of the night to puzzle this out, but it’s a godsend all the same.”

He sat down in the dirt, the book open on his knees. Simon hovered close over his shoulder. The two were already absorbed in those all-important pages.

“Otho”, said Newton, “will you go up and give Grag a hand in? The natives won’t dare to follow us in here on forbidden ground.”

AND that was the last thing he said that night, except to exchange a few terse remarks with Simon on the intricacies of some formulae or equation.

Grag and Otho waited. They did not speak. From beyond the high windows came a distant sound of voices that was like a bitter dirge.

Curt Newton read on and on in Carlin’s record. And as he read the terrible suspicion that had been born in his mind took form and shape and crystallized at last into a truth as horrifying as it was inescapable.

There was more in that record than mere scientific data. There were history and hope and terror and a great dream and a conclusion so staggering that the mind reeled before it — a conclusion that brought in itself a dreadful punishment.

Or was it, after all, a punishment?

Curt Newton flung the book from him. He leaped up and found that he was trembling in every limb, his body bathed in sweat. “It’s ghastly, Simon!” he cried. “Why would they have let such an experiment go forward?”

Simon’s lens-like eyes regarded him calmly. “No knowledge can be wrong in itself — only in its application. And the men of the Old Empire did forbid the use of this apparatus when they learned its effect. Carlin quotes here the inscription he found in the ruined city that so states. Also he mentions that he himself broke the seals on the great door.”

“The fool”, whispered Newton. “The crazy fool!” He glanced at the twin sets of glowing coils and then upward at the dome.

“He changed and went out along the Beam. And the natives, horrified by what he had done, caused the landslide to seal this place.”

“But Carlin did not come back”, said the Brain.

“No”, said Newton, broodingly. “No, he didn’t. Perhaps for some reason he couldn’t.”

The android’s bright eyes were watching him. “What was it that Carlin changed into, Curt?”

Curt Newton turned and said slowly, “It’s an almost unbelievable story. Yet Carlin notes every source, here and in the ruined city.”

He paused as though trying to shape what he had learned into simpler terms.

“In the days of the Old Empire the Vulcanian scientists had a predominant interest in the Sun. In fact it appears that Vulcan was first settled as an outpost for the study of solar physics. And somewhere, in the course of those centuries-long researches into the life of the Sun, one man discovered a method of converting the ordinary matter of the human body into something resembling solar energy — a cohesive pattern of living force able to come and go at will into the very heart of the Sun.

“This was not destruction, you understand — merely conversion of a matter-pattern into an analogous functioning energy-pattern. By reversing the field the changed matter could be returned to its original form. And, since the mental and sensory centers remained functioning in the altered pattern, thought and perception remained intact though different.

“Never before had there been such a possibility of uncovering the inmost secrets of solar life — and the study of suns was vital to a transgalactic civilization. The scientists entered the conversion field and became — Children of the Sun.”

Otho caught his breath with a sharp hissing sound.

“So that’s the meaning of the inscription — and the legend! Do you mean that those little wisps of flames we saw were once men?”

Newton did not answer, looking away at the tall golden coils that seemed to pulse with the Sun’s own light. But the Brain spoke dryly.

“Curtis did not tell you quite all. The lure of the strange life in the Sun proved too much for many of the men who were changed. They did not come back. And therefore the use of the converters was forbidden and this laboratory was sealed — until Carlin came and opened it again.”

“And now he’s out there”, said Captain Future as though to himself. “Carlin changed and went out there, and then couldn’t get back.” He swung around suddenly to face them. His tanned face was set. “And I’m going after him”, he said. “I’m going to bring him back.”

OTHO cried out, “No! Curt, you’re mad! You can’t do such a thing!”

“Carlin did.”

“Yes, and maybe he’s dead or worse!” The android caught Newton’s arm. He pleaded, “Even if you went after him how could you find him? And if you did suppose you found that you couldn’t get back either? These machines are ancient and might fail.”

“For once”, said Grag emphatically, “Otho is right. Every word of it!”

“And I must agree with both of them”, said Simon Wright. “Curtis, this course of action is both madness and folly.”

Newton’s gray eyes had grown cold with a remoteness that made Otho step back away from him. His face was now flintlike in its stubborn resolution. “Carlin was our friend”, he said quietly. “He stood by us when we needed him. I have to go after him.”

“Very well, Curtis”, Simon answered. “But you are not going for friendship nor to save Philip Carlin. You are going because you yourself want to.”

NEWTON turned a sharp and startled glance upon the Brain.

“And remember”, Simon added, “if you do not return none of us can go after you.”

The stone vault was silent then. High above through the triple windows a gleam of light came dancing in, cruel and bright as a golden spear. Vulcan had turned her face sunward and the Beam was come again.

Newton said softly, “I’ll come back. I promise you. Now come here and study these controls.”

In somber surrender Simon Wright said, “Your eagerness for the unknown was bound to bring disaster some time. I think this may be the time.”

But he came to the controls. These were simple and the careful translation of the inscriptions made their operation quite clear. They found that Carlin had adjusted them with great delicacy.

He had meant to return. Yet he had not returned. Why not? Newton could not believe that a landslide of soil could be barrier to a shape of living energy that could penetrate the depths of the Sun.

Why then had Carlin not come back? What was there out in the blazing thundering fury of that Sun-world that held and trapped those who went there? Captain Future remembered the inscriptions above the niches and the somber words of Simon Wright and shuddered, somewhere deep within him.

Almost in that moment he wavered. But over his head the light of the Beam burned and brightened and he could not have stopped then, even if he had so wished.

“You understand now?” he asked his comrades. “The machines draw their power from the magnetic field of Vulcan itself, which is tremendous — cutting as it does across the magnetic field of the Sun. So there is a never-failing power source. The controls are properly set. Your job will be to see that they aren’t touched.”

Grag and Otho nodded silently. Simon Wright said nothing. He was watching Curt with a bitter concentration.

Newton walked toward the converter. He stood where Carlin had stood and stripped himself naked. Then he paused, looking at the tall coils of crystal that were full of golden fire. The corded muscles of his body quivered and his eyes were strange. He stepped up onto the dais between the coils.

A blaze of golden light enveloped him. He could see the others through it as through a burning veil, Otho’s pointed face full of fear and sadness and a kind of rage, huge Grag looking almost pathetically puzzled and worried in the way he leaned forward with outstretched arms, Simon hovering and watching broodingly.