I caught one last glimpse of two people — a man and a woman, both naked — who seemed to hurtle across the beach. A shadow fell briefly over the car, perhaps cast by one of the immense animals of this Age; but soon we were moving too rapidly for such details to be discernible, and we fell into the colorless tumult of time travel.

The heavy Palaeocene sun leapt across the Sea, and I imagined how from the point of view of our transition through time the earth spun like a top on its axis, and rocketed around its star. The moon, too, was visible as a hurtling disc, rendered shadowy by the flickering of its phases. Soon the sun’s daily passage merged into the band of silver light which dipped between equinoctial limits, and day and night melted into the uniform blue-gray glow I have described before.

The dipterocarps trees of the forest shivered with growth and death, and were shouldered aside by the vigorous growth of younger plants; but the scene around us — the forest, the Sea smoothed by our time-passage to a glassy plain — remained static in its essentials, and I wondered if, despite all my and Nebogipfel’s efforts, men had after all failed to survive, here in the Palaeocene.

Then — quite without warning — the forest withered and vanished. It was as if a blanket of greenery had been ripped back from the soil. But the land was scarcely left bare; as soon as the forest was cleared, a melange of blocky brown and gray — the buildings of an expanding First London — swept over the earth. The buildings flowed over the denuded hills and down, past us, to the Sea, there to sprout into docks and harbors. The individual constructions shivered and expired, almost too fast for us to follow, though one or two persisted long enough — I suppose for several centuries — to become almost opaque, like crude sketches. The Sea lost its blue tinge and mutated into a sheet of dirty gray, its waves and tides made into a blur by our passage; the air seemed to take on a brown tinge, like an 1890s London fog, which gave the scene something of a dirty, twilit glow, and the air about us felt warmer.

It was striking that as the centuries fell away, regardless of the fate of individual buildings, the general outlines of the city persisted. I could see how the ribbon of the central river — the proto-Thames — and the scars of major road routes remained, in their essentials, unchanged by time; it was a striking demonstration of how geomorphology, the shape of the landscape, dominates human geography.

“Evidently our colonists have survived,” I said to Nebogipfel. “They have become a race of New Humans, and they are changing their world.”

“Yes.” He adjusted his skin slit-mask. “But remember we are traveling at several centuries per second; we are in the midst of a city which has already persisted for some thousands of years. I doubt that little is left of the First London we saw established.”

I peered around, my curiosity strong. Already my little band of exiles must be as remote to these New Humans as had been the Sumerians, say, from 1891. Had any memory persisted, in all this wide and bustling civilization, of the fragile origins of the human species in this antique era?

I became aware of a change in the sky: an odd, green-tinged flickering about the light. I soon realized it was the moon, which still sailed around the earth, waxing and waning through its ancient cycle too fast for me to follow — but the face of that patient companion was now stained green and blue — the colors of earth, and life.

An inhabited, earthlike moon! This New Humanity had evidently traveled to the sister world in Space Machines, and transformed it, and colonized it. Perhaps they had developed into a race of moon-men, as tall and spindly as the low-gravity Morlocks I had encountered in the Year 657,208! Of course I could not make out any detail, as the moon’s month-long orbit took it spinning across my accelerated sky; and of that I was regretful, for I would have loved to have had a telescope and to make out the waters of new oceans lapping those deep, ancient craters, and the forests spreading across the dust of the great maria. How would it be to stand on those rocky plains — to be cut loose of Mother Earth’s leading-strings? With every step in that reduced gravity one would fly through the thin, cold air, with the sun fierce and motionless overhead; it would be like the landscape of a dream, I thought, with all that glare, and plants less like earthly flora than the things I imagined among the rocks at the bottom of the sea…

Well, it was a sight I should never witness. With an effort, I returned in imagination from the moon, and fixed my attention on our situation.

Now there was some movement in the western sky, low against the horizon: firefly lights flickered into life, jerked across the heavens, and settled into place, there to remain for long millennia, before fading to be replaced by others. There was soon quite a crowd of these sparks, and they coalesced into a sort of bridge, which spanned the sky from horizon to horizon; at its peak, I counted several dozen lights in this city in the sky.

I pointed this out to Nebogipfel. “Are they stars?”

“No,” he said evenly. “The earth rotates still, and the true stars must be too obscured to be visible. The lights we see are hanging in a fixed position over the earth…”

“Then what are they? Artificial moons?”

“Perhaps. They are certainly placed there by the actions of men. The objects may be artificial — constructed of materials hauled up from the earth, or from the moon, whose gravity well is so much shallow. Or they may be natural objects towed into place around the earth by rockets: captured asteroids or comets, perhaps.”

I peered at those jostling lights with as much awe as any cave-dweller might stare at the light of a comet beating over his upturned, ignorant head!

“What would be the purpose of such stations in space?”

“Such a satellite is like a tower, fixed over the earth, twenty thousand miles tall…”

I grimaced. “Quite a view! One could sit in it and watch the evolution of weather patterns over a hemisphere.”

“Or the station could serve for the transmission of telegraphic messages from one continent to another. Or, more radically, one could imagine the transfer of great industries — heavy manufacture, or the generation of power, perhaps — to the comparative safety of high earth orbit.”

He opened his hands. “You can observe for yourself the degradation of the air and water around us. The earth has a limited capacity to absorb the waste products of human industry, and with enough development, the planet could even be rendered uninhabitable.

“In orbit, though, the limits to growth are virtually infinite: witness the Sphere, constructed by my own species.”

The temperature continued to increase, as the air grew more foul. Nebogipfel’s improvised Time-Car was functional, but poorly balanced, and it swayed and rocked; I clung to my bench miserably, for the combination of the heat, the swaying and the usual vertigo induced by time travel gave me a most nauseous feeling.