Wilson set down his glass. "Okay, Joe Whatever-your-name-is, trot out that explanation and make it snappy."
"I'll do that," agreed Joe. "That dingus I came through"-he pointed to the circle- "that's a Time Gate."
"A what?"
"A Time Gate. Time flows along side by side on each side of the Gate, but some thousands of years apart―just how many thousands I don't know. But for the next couple of hours that Gate is open. You can walk into the future just by stepping through that circle." The stranger paused.
Bob drummed on the desk. "Go ahead. I'm listening. It's a nice story."
"You don't believe me, do you? I'll show you." Joe got up, went again to the wardrobe and obtained Bob's hat, his prized and only hat, which he had mistreated into its present battered grandeur through six years of undergraduate and graduate life. Joe chucked it toward the impalpable disk.
It struck the surface, went on through with no apparent resistance, disappeared from sight.
Wilson got up, walked carefully around the circle and examined the bare floor. "A neat trick," he conceded. "Now I'll thank you to return to me my hat."
The stranger shook his head. "You can get it for yourself when you pass through."
"Huh?"