The white expanse grew still, coming nearer and nearer toward us, rolling slowly south and covering all the country it passed over with a blanket of whiteness. It came nearer toward us, moving with very slow speed, considering the rapidity of our progress in time. Now, above the shrill winds around us, there came the dull, grinding roar of the white blanket's passage. South rolled the gleaming sheet, until it had almost reached the ground directly beneath the car. I recognized, now, the material of that gleaming expanse. "Ice!" I shouted in Lantin's ear, and he started, glanced down toward it, then nodded. A moment he studied the grinding wave below, then leaned over and shouted a single word in my ear: "Glacier!" The word was like a blinding flood of light on my thoughts. A glacier! And that was the meaning of this white tide from the north, this vast, resistless flood of ice that was rolling south over the world as it had rolled ages before. The mightiest force on earth, and the slowest, moving with deliberate, unswerving steadiness, calm and majestic, carving mountains and valleys, changing the very face of the earth. It had swept down over the earth before, had forced primeval man down to the very equator before it receded, and now the thing was re-enacting itself before my eyes. Fascinated, I watched the white masses forging south. * * * * * While we hung high above it, the gleaming, solid flood rolled on until it had obscured the last speck of land on the southern horizon, so that as far as we could see stretched nothing but the glistening fields of ice. The air in the car had become suddenly bitter cold, and as frost and rime began to congeal on the windows, I hastened over to the heating apparatus and switched it on. The glasses cleared soon, and we sped on into the future, but the white expanse below us seemed changeless. I plucked at Lantin's sleeve, and when he turned, shouted to him, "Go back?", pointing to the gleaming frozen masses below. "No!" he yelled, over the roar of the gale; "I'm going to circle a bit." With the words, he snapped off the time-wave, and we came to a rest, in time. The dials now registered a little over fifteen thousand years, and with our stopping, the winds outside the car died away and we had a chance to converse in normal tones. "Nothing but ice here," said Lantin, "and we can't tell how long it will last. I think the best plan would be to sweep around in a great circle, and look for any signs of the Raider's presence. If we see nothing we can go on into time and stop every few hundred years to circle again."