You start to say something, but by then I'm pressing a black button, and everything outside will disappear. You look for your house, but it isn't there. There is exactly nothing there—in fact, there is no there. You are completely outside of time and space, as best you can guess how things are.
You can't feel any motion, of course. You try to reach a hand out through the field into the nothing around you and your hand goes out, all right, but nothing happens. Where the screen ends, your hand just turns over and pokes back at you. Doesn't hurt, and when you pull your arm back, you're still sound and uninjured. But it looks frightening and you don't try it again.
Then it comes to you slowly that you're actually traveling in time. You turn to me, getting used to the idea. "So this is the fourth dimension?" you ask.
Then you feel silly, because you'll remember that I said you'd ask that. Well, I asked it after I was told, then I came back and told it to you, and I still can't help answering when you speak.
"Not exactly," I try to explain. "Maybe it's no dimension—or it might be the fifth; if you're going to skip over the so-called fourth without traveling along it, you'd need a fifth. Don't ask me. I didn't invent the machine and I don't understand it."
"But...."
I let it go, and so do you. If you don't, it's a good way of going crazy. You'll see later why I couldn't have invented the machine. Of course, there may have been a start for all this once. There may have been a time when you did invent the machine—the atomic motor first, then the time-machine. And when you closed the loop by going back and saving yourself the trouble, it got all tangled up. I figured out once that such a universe would need some seven or eight time and space dimensions. It's simpler just to figure that this is the way time got bent back on itself. Maybe there is no machine, and it's just easier for us to imagine it. When you spend thirty years thinking about it, as I did—and you will—you get further and further from an answer.
Anyhow, you sit there, watching nothing all around you, and no time, apparently, though there is a time effect back in the luggage space. You look at your watch and it's still running. That means you either carry a small time field with you, or you are catching a small increment of time from the main field. I don't know, and you won't think about that then, either.
I'm smoking, and so are you, and the air in the machine is getting a bit stale. You suddenly realize that everything in the machine is wide open, yet you haven't seen any effects of air loss.