"With nothing to tell which was up and which down, we lost our level and couldn't find it again. I've flown upside down for five minutes, going through a cloud, and didn't know it until my barometer dropped upward. We're all right, but what's happened to the earth?" Gerrod cautiously made his way to a point beside Davis, who was driving with his eyes glued to the instruments. That incredible vastness into which the machine seemed to be boring was appalling. They seemed to be speeding madly from nothingness into nothingness, with nothing below them and nothing above. They were alone in a universe of air. Gerrod stared ahead at the cloud bank behind which the sun seemed to be hiding. "There's the sun, all right. What's our barometer reading?" "Eight thousand feet." "Try dipping, by the inclinometer." Davis did so. Though there was not the slightest change in the appearance of the sky that compassed them all about, the barometer quivered from eight thousand feet to seven, and then to six. Gerrod suddenly uttered an exclamation: "The sun's coming out!" The fiery disk of the sun peered slowly from behind the edge of the cloud bank. "There's _another_!" From the opposite side of the cloud bank a second sun could be seen, slowly appearing as had the first. The two suns swam away from the fringe of the cloud and glared at each other. "I've got it!" Gerrod struck his knee with his hand. "What fools we are!" "I'm glad we're only fools," said Davis mildly. "I've been afraid we had gone mad. What's happened?" "Why, the water," Gerrod said excitedly, "the water is perfectly calm and reflects like a mirror. We don't see the sky below us. We see the reflection of the sky. And that isn't a second sun," he pointed; "that's the reflection of the sun." "Only, the water doesn't reflect like that," said Davis. "At least, not from straight overhead. Open a side window and look directly downward." Gerrod did so, and exclaimed again: "I'm right, I tell you! Directly under us I can see the reflection of our plane, flying upside down." Davis took a quick glance. "I guess you are right, after all," he admitted, "but the water doesn't reflect like that normally. Something queer must have happened." He was silent a moment, while his eyes swept the distance before them keenly. "Here's another proof you're right. There's the yacht we're looking for." Far away, its white hull turned to red gold by the first rays of the sun, they saw the yacht, motionless on the water. And in striking corroboration of Gerrod's hypothesis, they saw every line and every spar reflected in the water below. Davis shifted his course to bear for the yacht and dipped down until he was only five hundred feet above the strange, mirrorlike surface of the sea. Below them they could see the spreading wings of their seaplane reflected from the still water.