"If you ask me," vouchsafed Syd O'Brien gloomily, "we've probably marched ourselves right into some sort of ancient torture chamber. An Iron Maiden, or something like that. We'll probably end up under the moat or being cooked in boiling mud--" He stared about him suspiciously. "Do these walls look like they're closing in on us?" His brother chuckled. "Cheerful little cherub, isn't he? I agree with the doctor; you shouldn't open that trap door just yet, Barrett. But I don't think we're in any danger. Evidently this chamber was a secret of the ancient priesthood. They wouldn't build anything to hurt themselves. Wherever it's taking us--" "Taking us?" interrupted Ramey. "What's all this talk about movement? We don't seem to be going anywhere." * * * * * Dr. Aiken permitted himself a thin smile. "Spoken like a true airman, Ramey. I'm afraid your profession has accustomed you to judge motion by external appearances. Within this closed chamber we have no object relative to which we can judge speed or direction. But by the hum of the motors, movement of these several dials, it is perfectly obvious we are doing _something_. Just what, I cannot say." Here a frown flickered across the forehead of the older man. "It is quite true that if we move either up or down there should be a visceral sensation similar to that experienced in elevators. Similarly, were we moving in a lateral direction we should have felt the shock of over-balanced inertia when we started in one or another direction. Since we did not feel these things there is only one other possibility, but it is so fantastic--" "It ain't fantastic," broke in Red Barrett. "It's whacky. We ain't going up or down; we ain't going sideways. That's all the directions there is." "All the _common_ directions known to man," corrected Dr. Aiken slowly. "There is one other about which we know absolutely nothing. A direction of flight which is, at best, but a mathematical concept--" This time Sheila Aiken stared at her father. "Daddy, it's unbelievable. You can't mean--?" "I venture no opinion," said the old man mildly. "I am simply trying to apply to a most unusual situation the rules of logic." Ramey gave up. He looked at the girl helplessly. "What does he mean, Sheila?" There was equal helplessness, and for the first time, an expression of uncertainty, in the girl's eyes as she answered. "He means--we may be moving across Time, Ramey!" "Time!" For a moment Ramey was jarred completely out of his self-possession. Then his sense of humor came to his rescue. "Oh, come now! We _are_ letting ourselves go hogwild! It's been a hell of a day, I know. And we've had some unnerving experiences, but--_Time!_"