He quit using the burner for any purpose and began a daily inspection of every square inch of the bubble's walls, marking with white chalk all the welding spots that appeared to be definitely weakened. Each day he found more to mark and soon the little white circles were scattered across the walls wherever he looked. When he was not working at examining the walls he could feel the windows watching him, like staring eyes. Out of self defense he would have to go to them and stare back at the emptiness. Space was alien; coldly, deadly, alien. He was a tiny spark of life in a hostile sea of Nothing and there was no one to help him. The Nothing outside was waiting day and night for the most infinitesimal leak or crack in the walls; the Nothing that had been waiting out there since time without beginning and would wait for time without end. Sometimes he would touch his finger to the wall and think, _Death is out there, only one-sixteenth of an inch away_. His first fears became a black and terrible conviction: the bubble could not continue to resist the attack for long. It had already lasted longer than it should have. Two million pounds of pressure wanted out and all the sucking Nothing of intergalactic space wanted in. And only a thin skin of metal, rotten with brittle welding spots, stood between them. It wanted in--the Nothing wanted in. He knew, then, that Horne and Silverman had not been insane. It wanted in and someday it would get in. When it did it would explode him and jerk out his guts and lungs. Not until that happened, not until the Nothing filled the bubble and enclosed his hideous, turned-inside-out body would it ever be content ... * * * * * He had long since quit wearing the magnetized shoes, afraid the vibration of them would weaken the bubble still more. And he began noticing sections where the bubble did not seem to be perfectly concave, as though the rolling mill had pressed the metal too thin in places and it was swelling out like an over-inflated balloon. He could not remember when he had last attended to the instruments. Nothing was important but the danger that surrounded him. He knew the danger was rapidly increasing because whenever he pressed his ear to the wall he could hear the almost inaudible tickings and vibrations as the bubble's skin contracted or expanded and the Nothing tapped and searched with its empty fingers for a flaw or crack that it could tear into a leak. But the windows were far the worst, with the Nothing staring in at him day and night. There was no escape from it. He could feel it watching him, malignant and gloating, even when he hid his eyes in his hands.