she nodded. "you'll sweep away his life work with a few words and a few sheets of paper."

"my own work, too."

"oh, but won't you understand? you're young. i'm young. youth loves to shatter the old idols. it feasts on the broken shards of destruction. it destroys the old ideas to make way for its own. but he's not young like us. he has only his past work to live on. if you shatter that, he'll have nothing left but a futile resentment. i'll be pent up with a broken old man who'll destroy me along with himself. darling, i'm not saying you're wrong—i'm only asking you to wait a little."

she was crying openly now. the boy took her by the arm and led her to the crusted window. she turned her face away from the light—away from him. the boy said: "he was my teacher. i worship him. what i'm doing now may seem like treachery, but it's only treachery to his old age. i'm keeping faith with what he was thirty years ago—with the man who would have done the same thing to his teacher."

she cried: "but are you keeping faith with me? you, who will have all the joy of destroying and none of the tedious sweeping away the pieces. what of my life and all the weary years to come when i must coddle him and soothe him and lead him through the madness of forgetting what you've done to him?"

"you'll spend your life with me. i break no faith with you, barbara."

she laughed bitterly. "how easily you evade reality. i shall spend my life with you—and in that short sentence, poof!"—she flicked her hand—"you dismiss everything. where will he live? alone? with us? where?"

"that can be arranged."

"you're so stubborn, so pig-headed in your smug, righteous truth-seeking. steven—for the very last time—please. wait until he's gone. a few years, that's all. leave him in peace. leave us in peace."

he shook his head and started toward the oaken doors. "a few years waiting to salvage the pride of an old man, a few more catastrophies, a few more thousand lives lost—it doesn't add up."

she sagged against the window, silhouetted before the riot of color, and watched him cross to the doors. all the tears seemed drained out of her. she was so limp i thought she would fall to the floor at any instant. and then, as i watched her, i saw her stiffen and i realized that another figure had entered the foyer and was rushing toward the boy. it was an oldish man, bald and with an ageless face of carved ivory. he was tall and terribly thin. his eyes were little pits of embers.

he called: "steven!"

the boy stopped and turned.

"steven, i want to talk to you."

"it's no use, sir!"

"you're headstrong, steven. you pit a few years' research against my work of a lifetime. once i respected you. i thought you would carry on for me as i've carried on for the generations that came before me."

"i am, sir."

"you are not." the old man clutched at the boy's tunic and spoke intensely. "you betray all of us. you will cut short a line of research that promises the salvation of humanity. in five minutes you will wipe out five centuries of work. you owe it to those who slaved before us not to let their sweat go in vain."

the boy said: "i have a debt also to those who may die."

"you think too much of death, too little of life. what if a thousand more are killed—ten thousand—in the end it will be worth it."

"it will never be worth it. there will never be an end. the theory has always been wrong, faultily premised."

"you fool!" the old man cried. "you damned, blasted young fool. you can't go in there!"

"i'm going, sir. let go."

"i won't let you go in."

the boy pulled his arm free and reached for the doorknob. the old man seized him again and yanked him off balance. the boy muttered angrily, set himself and thrust the old man back. there was a flailing blur of motion and a cry from the girl. she left the window, ran across the room and thrust herself between the two. and in that instant she screamed again and stepped back. the boy sagged gently to the floor, his mouth opened to an o of astonishment. he tried to speak and then relaxed. the girl dropped to her knees alongside him and tried to get his head on her lap. then she stopped.

that was all. no shot or anything. i caught a glimpse of a metallic barrel in the old man's hand as he hovered frantically over the dead boy. he cried: "i only meant to—i—" and kept on whimpering.

after a while the girl turned her head as though it weighed a ton, and looked up. her face was suddenly frostbitten. in dull tones she said: "go away, father."

the old man said: "i only—" his lips continued to twitch, but he made no sound.

the girl picked up the portfolio and got to her feet. without glancing again at her father, she opened the doors, stepped in and closed them behind her with a soft click. the debating voices broke off at the sight of her. she walked to the head of the table, set the portfolio down, opened it and took out a sheaf of type-script. then she looked at the amazed men who were seated around the table gaping at her.

she said: "i regret to inform the stabilizers that mr. steven wilder has been unavoidably detained. as his fiancée and co-worker, however, i have been delegated to carry on his mission and present his evidence to the committee—" she paused and went rigid, fighting for control.

one of the stabilizers said: "thank you. will you give your evidence, miss ... miss?"

"barbara leeds."

"thank you, miss leeds. will you continue?"

with the gray ashes of a voice she went on: "we are heartily in favor of s. r. 930 prohibiting any further experimentation in atomic energy dynamics. all such experiments have been based on—almost inspired by the fitzjohn axioms and mathematic. the catastrophic detonations which have resulted must invariably result since the basic premises are incorrect. we shall prove that the backbone of fitzjohn's equations is entirely in error. i speak of

i = (b/a) π i e/μ..."

she glanced at the notes, hesitated for an instant, and then continued: "fitzjohn's errors are most easily pointed out if we consider the leeds derivations involving transfinite cardinals—"

the tragic voice droned on.

i said: "c-cut."

there was silence.

we sat there feeling bleak and cold, and for no reason at all, the icy sea-green opening bars of debussy's "la mer" ran through my head. i thought: "i'm proud to be a human—not because i think or i am, but because i can feel. because humanity can reach out to us across centuries, from the past or future, from facts or imagination, and touch us—move us."

at last i said: "we're moving along real nice now."

no answer.

i tried again: "evidently that secret experiment that destroyed existence was based on this fitzjohn's erroneous theory, eh?"

the c-s stirred and said: "what? oh—yes, carmichael, quite right."

in low tones the controller said: "i wish it hadn't happened. he was a nice-looking youngster, that wilder—promising."

i said: "in the name of heaven, sir, it's not going to happen if we pull ourselves together. if we can locate the very beginning and change it, he'll probably marry the girl and live happily ever after."

"of course—" the controller was confused. "i hadn't realized."

i said: "we've got to hunt back a lot more and locate this fitzjohn. he seems to be the key man in this puzzle."

and how we searched. boys, it was like working a four-dimensional jig saw, the fourth dimension in this case being time. we located a hundred universities that maintained chairs and departments exclusively devoted to fitzjohn's mathematics and theories. we slipped back a hundred years toward the present and found only fifty and in those fifty were studying the men whose pupils were to fill the chairs a century later.

another century back and there were only a dozen universities that followed the fitzjohn theories. they filled the scientific literature with trenchant, belligerent articles on fitzjohn, and fought gory battles with his opponents. how we went through the libraries. how many shoulders we looked over. how many pages of equations we snap-photographed from the whirling octahedron for future reference. and finally we worked our way back to bowdoin college, where fitzjohn himself had taught, where he worked out his revolutionary theories and where he made his first converts. we were on the home stretch.

fitzjohn was a fascinating man. medium height, medium color, medium build—his body had the rare trick of perfect balance. no matter what he was doing, standing, sitting, walking, he was always exquisitely poised. he was like the sculptor's idealization of the perfect man. fitzjohn never smiled. his face was cut and chiseled, as though from a roughish sandstone; it had the noble dignity of an egyptian carving. his voice was deep, unimpressive in quality, yet unforgettable for the queer, intense stresses it laid on his words. altogether he was an enigmatic creature.

he was enigmatic for another reason, too, for although we traced his career at bowdoin backward and forward for all its forty years, although we watched him teach the scores and scores of disciples who afterward went out into the scholastic world to take up the fight for him—we could never trace fitzjohn back into his youth. it was impossible to pick him up at any point earlier than his first appearance on the physics staff of the college. it seemed as though he were deliberately concealing his identity.

yarr raged with impotent fury. he said: "it's absolutely aggravating. here we follow the chain back to less than a half century from today and we're blocked—" he picked up a small desk phone and called upstairs to the data floors. "hullo, cullen? get me all available data on the name fitzjohn. fitzjohn. what's the matter, you deaf? f-i-t-z ... that's right. be quick about it."

i said: "seems as if fitzjohn didn't want people to know where he came from."

"well," yarr said pettishly, "that's impossible. i'll trace him backward second by second, if i have to!"

i said: "that would take a little time, wouldn't it?"

"yes."

"maybe a couple of years?"

"what of it? you said we had a thousand."

"i didn't mean you to take me seriously, dr. yarr."

the small pneumatic at yarr's desk whirred and clicked. out popped a cartridge. yarr opened it and withdrew a list of figures, and they were appalling. something like two hundred thousand fitzjohns on the earth alone. it would take a decade to check the entire series through the integrator. yarr threw the figures to the floor in disgust and swiveled around to face us.

"well?" he asked.