It was upon the fifteenth day after our start from Earth, the first day of July as I noted by Earth-reckoning, that we crossed the orbit of Uranus. As we approached that orbit, only our recording distance-dials, of course, marking the fact that we were nearing the path of Uranus, I stood or rather floated with Marlin and Whitely at the flier's rear windows, gazing backward. Behind us gleamed in the star-swept heavens the planets past which we had come, and those others beyond them. Great Saturn with his vast rings that had almost been our deaths was already dwindling fast, as our flier shot out from it with its force-ray pressing with ceaseless power against it. Already the huge ringed planet was but a tiny yellow disk of light to our eyes, so far out from it we were. To the left, too, shone the white star of giant Jupiter, small but intensely brilliant still, while farther distant and infinitely fainter was the red spark that was Mars. Our eyes shifted from these to the bluish light-point that was Earth, and then beyond it to the little disk of brilliant fire that was the sun, its light and heat reaching us now in the smallest of quantities as we fled on into the chill immensities of the outer reaches of the solar system. There close beside that fiery little sun-disk we could also make out the silvery little light-point that was Venus, and by making use of a small hand-glass could also discern closer even beside the sun the tiny point of rosy light that we knew to be Mercury, smallest and inmost of all the planets. But as we watched there, as our space-flier hurtled on at unvarying, colossal speed over the orbit of Uranus, it was toward Uranus itself we were gazing. Far back from us on the solar system's other side hung the green spot of light that was Uranus, booming onward in its vast path around the sun, but though we watched steadily through the hand-glass toward it we were unable to make out the four small moons that accompany the great green planet, which shone with a deeper green even than the greenish spot of Neptune, ahead. "Uranus--Venus--Mercury----," said Marlin, as he gazed musingly backward. "Those three we have not passed, yet they're no greater mysteries to us than those that we have passed. But some day----" "Some day----," I repeated, staring back, lost in thought myself, not completing, any more than Marlin, the thought that I had started to express.