To the right of the floating ship there was only tawny-blue ocean that seemed much darker than ordinary because McCauley was looking down into its depths instead of at a sky reflection from its surface. Behind the ship there was a clumping of the white specks. These cloud masses would be above and around the Cape Verde Islands, now tens of scores of miles to the rear. Below and to the left there was an amorphousness, an indefiniteness peeping up from beneath the cloud cover. That would be Africa. McCauley could see for enormous distances over the cloud-hidden land. He knew that he floated over Senegal and British Guinea and French Guinea and Liberia and the Ivory Coast, all in a matter of tens of seconds. But he could see only at intervals between tufts of white-cottony vapor. Ahead, too, the dark-colored sea swept in, right to left, and in half minutes or less there was no land at all except behind him. Away ahead there was more of Africa, to be sure, because the X-21 sped along a line which would mark the limits of the Gulf of Guinea. The ship would cross the tip of Africa and head down past it to Antarctica. But McCauley would not see Africa again. The whiteness which was the horizon turned dim where the ship's bow aimed, and the dimness spread to the left. The edge of the round world turned black. It was Earth's crawling shadow creating night. Darkness sped toward the ship, still high above the last slightest trace of atmosphere and glittering intolerably in the unshielded glare of the sun. "It looks like we're all set, Furness," McCauley said with satisfaction. "We can relax, now, for all of twenty minutes." Furness did not answer. There was no sensation of weight, of course. Nothing weighed anything. Nothing could be considered light or heavy. The difference between a copper penny and the ship itself was purely imaginary. They had different masses, but both would weigh the same--zero. McCauley suddenly turned off the silent air-circulator in the cabin. He struck a match. The flame flared, but not as a rising leaf shape. It was a perfect ball of incandescence. But it did not continue to burn. It went out, and there was a ball of white smokiness where the flame had been. "I've heard that'd happen. I wanted to try it," McCauley said amusedly. A match requires oxygen in which to burn. On the ground, the chemically fostered first flame of the match-head heats the air, which rises and is replaced, whereby fresh oxygen reaches the place of combustion and supports it. But in the X-21, in free fall, hot air was no lighter than cold. It did not rise. The match exhausted the oxygen around it and went out. McCauley turned the air-circulator on again lest he and Furness be similarly surrounded by vitiated air. "Queer, eh?" said McCauley. Then he looked at Furness. Furness' eyes seemed filled with suffering. His pallor was deathlike. "What's the matter?" McCauley asked.