 Which item doesn't get mentioned while they're in the year 2150?
There is one fact no sane man can quarrel with ... You will, you know, so why quibble about it? At least, you always have ... or do ... or will. Yes, it'll be pretty obvious it must be a time machine. You'll be puzzling over what I'll tell you, and you'll be getting used to the idea that you are the man who makes atomic power practical. You can see a sort of foggy nothing surrounding the cockpit; it is probably the field that prevents passage through time from affecting us. You start to say something, but by then I'm pressing a black button, and everything outside will disappear. You are completely outside of time and space, as best you can guess how things are. Then you feel silly, because you'll remember that I said you'd ask that. "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. There may have been a time when you did invent the machine—the atomic motor first, then the time-machine. I figured out once that such a universe would need some seven or eight time and space dimensions. Maybe there is no machine, and it's just easier for us to imagine it. Anyhow, you sit there, watching nothing all around you, and no time, apparently, though there is a time effect back in the luggage space. That means you either carry a small time field with you, or you are catching a small increment of time from the main field. You suddenly realize that everything in the machine is wide open, yet you haven't seen any effects of air loss. Out there is neither time nor space, apparently. In spite of Einstein, you have always had the idea that time is an effect of gravity, and I sort of agree, still. He told me, just as I'm telling you, that it's an interstellar civilization." It gives out a coughing noise and the basement openings begin to click by us. There's no feeling of acceleration—some kind of false gravity they use in the future. Some of them can be decoded to stationery shops, fountains, and the like. You stop at a sign that announces: Trav:l Biwrou—F:rst-Clas Twrz—Marz, Viin*s, and x: Trouj:n Planets.
 flying vehicles
 flying vehicles  diamond makers  an elevator that you can't feel move  a modified English language