It was quite high, about half-way between the summit of the tower and the surface of the rock sky, and moving very slowly. It reminded Andreson of a legless centipede--a long, joined cylinder, with the same stony, red-veined texture that the great bowl presented. In the feeble light he thought he saw small openings appearing and vanishing: the space-beasts, moving about inside their mechanism! The brief glimpse was somehow the most horrible thing he had ever seen. He could distinguish at least two other tones in the gruesome buzzing, and he knew that the borer was not alone above the city. "They've learned that hollow things are deadly--learned from us," Atel spat out bitterly. "See the column of light inching out from the borer's nose? They are disintegrating a tunnel for their vacuum torpedoes. It's a slow-motion kind of warfare--but when one side wins constantly, it can't last forever. Feel the radiation?" Andreson discovered that he was scratching. His skin felt as if he had a mild sunburn. "The boring mechanism?" he suggested. "Right," Atel admitted, his tone grudging. "Matter-against-matter generates radiant heat. Space-against-space generates X-rays and worse. Deadly stuff! If our gunners can only--" Andreson never heard the end of the sentence. Without the slightest warning he was again sprawling through the hot dark air-- Alone! III Kimball's right shoe caught in a burrow and he fell again. This time the expected shock came late; evidently he had been on the brink of a pit of some sort, for his shoulders slammed against the hard ground with an unexpected impact, and he slewed down a long decline. He lay at the bottom for an indefinite period--neither time nor distance had any meaning in this blackness--and then got up again. Through the steady, muted roaring which had been in his ears ever since he had dropped from the torus coil, a roaring like the sound in a seashell, multiplied to the point of madness, a leathery muttering sound began to grow. He yanked his flashlight from the belt-clip and shot a cone of light upward. He was rewarded with a ululating, deafening scream, and something winged and huge sheared off from the beam. The muttering of the wings faded again, and with it went a sticky blubbering, like the crying of an idiot child. Sick at his stomach, he pumped a shot after it, and was surprised to hear it scream again. That would hold them for a while. They weren't very cautious about the automatic, for they seemed to expect that he would score a hit with it only by rare chance; but they hated the flashlight. They'd not try that dive-bombing stunt on him soon again. He could hear them settling around the rim of the pit. Deliberately he lit a cigarette. For a second he could see the bulky, pasty bodies and the blinded heads arching above him; then they all whispered with agony and drew away out of sight. Even the dim coal of the burning fag was too much for them.