He had been convinced that the only success in life came through achievement. As a scientist he trusted only what he could see and examine. "If it cannot be measured," a professor had once told him, "it is not worth thinking about."

He had laughed at the time, but now he saw clearly that the joke was on him. He blindly bought that empty philosophy, as did so many of his young colleagues, though they called it by different names and dressed it in altruistic rhetoric. Of course, he had told himself that his goals as a scientist were helpful to mankind and therefore worthy. But a real concern for his fellowman never entered into it. The goals were merely milestones on his private road to success.

The question he kept coming back to, the one uppermost in his mind at the moment, was a question of ultimates. What, ultimately, had he done with his life? Had it been wisely spent?

Sorrowfully, no. Spence, confronted with the naked facts, was forced to conclude that his life had been pretty much one long self-aggrandizing binge. And it had contributed nothing to anyone but to make him a dour, selfish gloryhound.

In short, it had been, except for momentary lapses, a life not worth living. Spence, his logic cool and keen as a computer's, stared unblinking at the conclusion and marveled that he should have tried so hard to save such a sorry life as his own.

There came over him a feeling of shame, of guilt so thick it clothed him like a garment. Never in his life had he felt guilty for anything That he should feel so now, when there was absolutely nothing to be done about it, was the final irony.

He dimly remembered a sort of prayer, uttered out of the frustration of the moment, as he had wandered in the wilderness desert of Mars not so long ago. That prayer came back to him now and mocked him, as his own lack of faith in anything beyond human ingenuity mocked him.

See how the worm turns! his ghostly accuser seemed to say. Faced squarely with its own mortality, the creature grasps at arty straw. Where, 0 foolish one, is your dignity? Where is respect? Do you not have courage enough even to end your life as Your 'Self.

You lived it? What right do you have to call upon one you never worshipped, never believed, never acknowledged? You lived by your beliefs-die by them!

Spence felt a chill in his chest as if an icy hand had closed around his heart. As much as he wanted it to be otherwise, he had to admit the accuser was right. For the first time in his life he saw himself for what he was. The sight sickened him. He desperately wished that somehow all that had happened could be reversed, that he could be given a, second chance.

The hope died, stillborn in his breast.

He reflected sadly that there were no second chances. And his plight was beyond reverse, beyond help, beyond hope. …

IN THIS WAY, ABSORBED in his pitiless introspection, Spence came into the city,

… THAT IT WAS A city he had no doubt. He had not noticed I that for the last four kilometers or so the roof of the cavern had been arching away gradually. By the time he reached the outskirts of this alien habitation he could not see the ceiling. He had been lumbering along oblivious to his surroundings when he saw something glimmering in front of him. Spence had raised his eyes and found himself standing before a weird assemblage of structures.

If pressed for a description, Spence would have said that the city appeared to him like a termite nest. He recalled pictures of the inside of such a nest from an entomology textbook, and looking upon the strange, elongated and flowing structures brought back the same image to him. On further inspection, though, the graceful interwoven cells looked like nothing at all that he had ever seen. And they gave not a hint of what kind of resident might have inhabited them.

This discovery brought none of the heady rapture of the explorer who believes he has found Eldorado at last, nor of the paleontologist who chances upon an unnamed saurian. He did not even feel the same elation experienced upon finding the footprint.

He just stood unmoving in his tracks, shaking his head in disbelief and wonder. It was simply too much to take in all at once. He did not know how to react, When he came to himself again he began threading through the winding pathways among the hivelike habitations, under curving arches and over half-buried burrow hills. He soon lost himself in the refined tangle of bending, interlacing shapes, as a small child in an enchanted forest.

His way was lit by the radiant lichen clinging to the sides of the dwellings. It was as if he moved through an elven world sparkling with magic and whispering voices. The voices were the swish of his steps as he passed hollow or curving shapely walls.

The more he saw of the city-formed of some kind of ado belike material such as ancient Indian settlements but harder, more durable-the further he walked, the more beautiful it seemed to him. And colorful. The dwellings were of various subtle hues: oranges, reds, violets, and browns in various subdued tones; deli cate earthen, or rather Martian, hues of ocher and sepia, madder and rust and buff, softly shimmering in their own faint light.

There were apertures and openings which he took to be windows and doors. These were of various shapes, all in keeping with the surrounding curve of the wall or archway of which they were a part. For this reason Spence could get no precise impressions of what the residents themselves might have looked like.

He poked his head into the darkened interiors of several dwellings and saw nothing at all to further the identification process. The rooms were the inner version of the outer structure, molded and graceful and, for all he could see, clean-swept and empty.

In his reverent ramble through the interlacing forms he struck upon a wide, meandering pathway between two ranks of towering structures. This he took to be a central trafficway.

The domiciles on either side of this street rose to a considerable height above the smooth, even surface he walked upon. Some of them branched over it in sinuous arches or tubes which wound snakelike to join a building on the other side.

The notion came to him that if he followed this trafficway he would end up in the center of the Martian city.

He was not wrong.

Within an hour of discovering the place he stood blinking in the center of a wide expanse surrounded on all sides by the queer architecture. The sheer alien beauty of the place still overwhelmed him. He had begun to think that the Martians, whatever their outward appearance, had been an elegant, peace-loving civilization. Such was the effect of the architecture on him. He did not for a moment consider that there might be any Martians still around. Everything he saw indicated a civilization which had long ago ceased to exist.

He sat down to rest on a smooth, mushroom-shaped projection, one of many which randomly dotted the central clearing. His vision blurred and wavered; he knew he was seriously dehydrated now. Dizziness played over him and he felt suddenly weaker, as if he were beginning to disintegrate. He imagined an exploring party of the future wandering into the square and finding his bones, and mistaking him for the last remaining Martian.

As Spence sat holding the last unraveling threads of his strength his gaze happened to fall on one of the hives across the square, set apart from the others. For some reason the structure took on an importance for him-he felt himself drawn to it, though outwardly it did not differ from any around it. It was roughly mound-shaped with bulging sides rising upward to become bulbous compartments and chambers.

Spence nodded in his remote inspection of the building. His eyes closed and he slid from the mushroom pod and rolled onto his side and fell asleep. …