She laughed, each sound a clear, musical tone, as if she had been struck by a desire to sing the _Bell Song_. "Don't you know your own language when you hear it? No, the Varese are not telepathic--few races are. But a truly telepathic race allied with us has provided our culture with a good stock of equipment for tapping various parts of the mind. We use it for education. We simply tapped your language centers while you were unconscious." A shadow passed across the glowing wall, and he heard the already-familiar hum of wings. A moment later a newcomer was outlined in the sunlight in a low doorway which seemed to open on empty space. It was a man, this time, a figure almost exactly Andreson's height, and perhaps a little older, though it was hard to judge. He smiled unpleasantly at the human, revealing two upper incisors which were slightly larger than the rest of his teeth, and demanded, "Well, what time is he?" "What time are you?" Andreson countered. "We've no record of you in our history. You could have flourished, died, or moved on a dozen times without our knowing it--our records go back only three thousand years." "Well taken," the Varan said, making himself comfortable on one of the odd "chairs." "We're not native, here, of course. But so far we've found no mammals on this planet, except a few egg-laying ones that aren't even entirely warm-blooded yet; so you _must_ be a considerable distance in our future. Furthermore, you're a time-traveller, which means that you know more than we do, for time is a problem we have never broken." The girl shook her head slowly, all traces of her former laughter vanished. "It's no use, Atel. He's here by accident, and isn't a scientist." "What's the matter?" Andreson said. Both faces looked so somber that he nearly forgot his own problem. "Are you in trouble?" "We're at war," the girl said softly. "And we shall probably be exterminated, all of us, before the year is over." Andreson remembered again the picture of the deserted city, and despite the hot sun he felt the same chill. "This planet you call Earth," Atel said, "has no life on its surface now with enough intelligence to count up to three. But after we had been here fifty-three of its years, we discovered that Earth has a civilization of its own all the same--_inside_." A dozen legends chased through Andreson's mind at once. "Cave-dwellers of some sort? It hardly seems credible." "No, not cave-dwellers. These aren't even solid, and they couldn't live in caves. They live _in_ the Earth--in the rock itself, and all the way down to the core. They are--space-beasts. They move through solid matter just as you and I move through space, and are stopped by space as we are stopped by a solid wall. In the air, for instance, we're safe from them, for what is to us a thin gas is for them a viscous, almost rigid medium. In the oceans, we meet on equal terms; but true solids are their natural medium." "How did you discover them?"