Can you form a mental picture of that? I hope so, for it was characteristic of all the movement that now began to assume visibility throughout the silent city. This building that melted--I come back to that word because it seems the only one suitable--was gone in a moment or two. Try to conceive that I did not see actual movement--not the physical movement we are accustomed to. They were tearing down that building--doubtless over a period of weeks. But I could not see any specific thing being done, any part of the building come off and move away. All such details were too rapid--far too rapid. What I saw, rather, was the _effect_ of movement; a change of aspect, not the movement itself. The building progressively looked smaller, until at last it was not there. Then another building began rising in its place. It grew steadily. It was as if I were blinking, and between each blink, with an unseen movement, it had leaped upward another story. It seemed a skeleton at first, and then it was clothed. I watched it, ignoring others further away, until it stood complete--a full block in depth and thirty or forty stories high. I began to realize now the tremendous acceleration of time velocity I was undergoing. The year-dial pointer very soon had moved to ten years; the pointer of the century-dial was stirring. Again I glanced at the clock. It was after eleven; I had been gone about an hour and a quarter. There was nothing that I had to do, and I moved about the cabin, looking out of each of the windows in turn. The city was rising; not one building, but hundreds. As my time velocity increased, I could no longer see them come and go individually. They were there--and then they were were gone, and others always larger and higher were in their stead. So I say the city was rising, coming up to meet me as I hung a thousand feet or more above it. Already one gigantic edifice to the south seemed to rear its spire far above me. The edges of the island stayed low, a fringe of the new and old mingled; but down the backbone, roughly following Broadway, great piles of steel and masonry were coming up. To the southeast I could make out the bridges over the river. There were others now, extraordinarily broad and high, dwarfing the older ones that stood neglected beside them. It was a period of tremendous activity. And suddenly I discovered that the southern half of Central Park was obliterated. I had drifted a little further north and was over it. A building was rising, coming up toward me so swiftly that its outlines were blurred and shadowy. I was gazing down through the window in the floor of the cabin, and caught a vague impression of a network of gigantic steel girders almost underneath the machine.