Henry's time machine was just about as I had antic.i.p.ated - a metallic chair with some scant leather upholstering, a large mirror-bright aluminum shield or reflector behind it, and a series of levers, dials, and b.u.t.tons on a control board attached to the platform on which the chair stood.

The room was windowless and all four walls - with the exception of three grated ventilators approximately shoulder high - were solid cement block. The floor was concrete and the ceiling was plastered.

I smiled. "Henry, your machine looks almost like an electric chair."

"Yes," he said musingly, "it does look rather like that, doesn't it?"

I stared at him. Could he have been so insidious as to actually... I studied the machine again. "Naturally I want a demonstration. How does it work?"

"Get into the chair and I'll show you which levers to pull."

The device did look a great deal like an electric chair. I cleared my throat. "I have a better idea, Henry. Suppose you take a trip in the chair. I'll just wait right here until you return."

Henry gave it a thought. "All right. But you'll have to leave the room."

Ah ha, I thought.

"You see when I start the machine," Henry said, "it creates quite a disturbance around me. That's why I had to make this room so solid. I've installed ventilators to take care of some of the turbulence, but I'm not too sure how well they work. I have no idea what might happen to you if you remained."

I smiled. "I might possibly be injured? Or killed?"

"Exactly. So if you'll leave and close the door I'll get on with it. And another precaution. When I return, you've got to be out of the room, too."

I chuckled to myself as I left and closed the door behind me. I lit a cigar and waited, amused.

What happened next was most impressive. First there was a low whine, as though a generator were starting. It rose gradually in pitch and then came a rumbling sound mixed with the undulating keen of a fierce wind. It increased in volume and lasted for approximately a minute.

Then it stopped abruptly and there was absolute silence.

Yes, I thought. Altogether a good show. But then it would have to be if Henry expected to extract two hundred and fifty thousand dollars from me.

I went to the door and opened it.

The room was empty!

I stood there gaping. It couldn't be! The only way out of the room was the door I had just entered and even that was certainly too small to pull the chair through. And the only other openings were the three grated ventilators and they were less than two feet square!

The whining suddenly rose again. Strong air currents swirled around the room and I found myself gasping as I fled the room and slammed the door behind me.

The noise became deafening and then, just as abruptly as before, it stopped.

The door clicked open and Henry stepped out of the room. Behind him I could see the time machine back in its place.

Henry appeared thoughtful. Finally he shook his head. "Cleopatra wasn't even good-looking."

My heart was still pounding. "You were gone only a minute or two."

He waved a hand. "In one time sense. Actually I spent an hour on her barge." He came back to the present. "You can raise two hundred and fifty thousand dollars?"

I nodded weakly. "It will take a week or two." I wiped my forehead. "Henry, I've got to take a trip on that chair."

Henry frowned. "I've been thinking that over, Mr. Reeves. No. You could steal my invention."

"But how? Wouldn't I have to come back here?"

"No. You could go into the past and then return to any place in the world. Perhaps a thousand miles from here."

He pulled a small wrench from his pocket and began disconnecting a section of the control panel.

"What are you doing?"

"I'm taking out some key transistors. I think I'll keep them on my person. That way if someone should steal my time machine he would find it useless."

Henry drove me back to my apartment, taking the same precautions as before, and then he left me.

In America we seem to have a feeling of guilt about discarding old license plates and Henry had been no exception. There had been four old sets of them nailed to the garage wall and I had memorized two of them.

I got Shippler on the phone. "Can you trace license numbers?"

"Yes, Mr. Reeves. I have connection at the state capitol."

I gave him the numbers. "The first is a 1958 license number and the second is 1959. I want the name and address of the owner as soon as possible. Phone me the moment you get the information."

I was about to hang up.

"Oh, Mr. Reeves. We have the report on your wife for yesterday. Would you like me to give it over the phone?"

I had forgotten about that. "Well?"

"She left the apartment yesterday morning at ten-thirty. She bought some orange sticks and nail polish at the drugstore."

"What shade of nail polish?" I asked dryly.

"Summer Rose," he said proudly. "Then she went to -"

"Nevermind all that. Did she meet anyone?"

"No, sir. Just the drugstore clerk. A woman. But in the evening she again left your apartment at three minutes after seven. She met a woman named Doris. My man overheard Doris say that she has twins."

I sighed.

"They went to a show and left at eleven-thirty."

I was not going to ask him the name of the picture. "Is that all?"

"Yes, sir. She returned to your apartment at eleven-fifty-six. The name of the picture..."

I hung up and made myself a whiskey and soda.

The idea of a time machine was fantastic. But was it really? We are all aware that there is a fourth dimension. And future travelers in s.p.a.ce will eventually have to use s.p.a.ce warp in order to reach planets that are physically inaccessible in the present time sense.

Diana came into the room with a manicure kit. "You look thoughtful."

"I have a lot to think about."

"Does it have anything to do with that man who was here? The inventor?"

I sipped my whiskey. "Suppose I told you that his time machine works?"

She began working on her nails. "I hope you haven't been taken in?"

I noticed that one of the bottles beside her was named Summer Rose. "And why should a time machine be impossible?"

"Don't tell me he's convinced you?"

I felt a bit defensive. "Perhaps."

She smiled. "Has he asked you for money?"

I watched her use nail polish remover. "How much do you think a time machine would be worth?"

She raised an eyebrow.

I held up a hand. "Let us just suppose that there is such a thing? How much would you be willing to pay for it?"

She examined her nails. "Perhaps a thousand or two. It might be an amusing toy."

"A toy?" I laughed. "My dear, don't you realize the tremendous import of such a thing? You could go into the past and ferret out any secret at all."

She glanced up. "Perhaps try simple blackmail?"

"My dear Diana, not simple blackmail, but blackmail extended, double, quadrupled. No nation's secrets would be safe from discovery. You could sell your services to the government ... any government ... for millions. You could be present at the most important council chambers, the most isolated laboratories..."

She looked up again. "Is that what you'd do if you had such a machine, use it for blackmail?"

I had let myself get carried away. I smiled. "Just indulging in fantasy, dear."

Her eyes seemed to calculate me. "Don't do anything foolish."

"My dear, I am the most cautious man in the world."

I decided that I would not hear from Shippler within the next half an hour and so I went to the post office.

I had a letter from Spender. He expressed keen disappointment that I had killed Turley instead of Atwood. He had played golf with Turley a number of times and would miss him. He also suggested that I return the fifteen thousand dollars or complete my a.s.signment.

Shippler phoned at three-thirty.

"Both of the license numbers belong to the same person," he said. "A Henry Pruitt. He lives at 2349 West Headley. This city."

I waited until ten that evening and then got my flashlight, a tape measure, and my ring of special keys from the wall safe and went down to my car.

Henry's house was in a spa.r.s.ely populated section of the city - there were empty lots on either side of his home. It was a two story building, but still relatively small. A garage stood next to the alley.

I parked my car a hundred feet down the street and lit a cigar. At eleven the lights in the living room went out and a few moments later they reappeared in what was evidently an upstairs bedroom.

After ten minutes, they too went out.

I waited another half an hour and then made my way through the littered lots to the garage. It had originally been a common two-car structure, but now the left-hand doors had been replaced by a solid cement block wall. I couldn't peer into the right-hand unit, because, as I'd noticed before, the windows had been covered by plywood. Henry clearly believed in absolute secrecy for his invention.

I measured the outside of the garage, the height, width, and length. Then I took the ring of keys out of my pocket and, after a few tries, succeeded in opening the door. I stepped inside, closed the door behind me, and turned on my flashlight.

Yes, this was the place I had been in earlier in the day - the four pairs of license plates nailed to the wall, the workbench at the far end, and the door leading to the time machine on the left.

I switched on the overhead light.

The door to the next room was also locked, but it presented no problem to me. I turned on the light, somewhat apprehensively.

Yes, there it was. The time machine!

For a moment, the idea of stealing it crossed my mind. But then I remembered that Henry had a section of the controls. And besides, how would I get it out of the room? The doorway was obviously too small.

For that matter, how had Henry gotten the machine into the room?

I pondered on that and decided he must have brought it in piece-meal and then a.s.sembled it.

What really concerned me was how he had managed, earlier in the day, to get the time machine out of the room.

That was what I was there to find out.

I began by examining the walls. They were cement block on all four sides and absolutely solid. I took measurements of the room and the entire inside of the garage. My computations showed that there were no secret compartments, no false chambers. I examined the ventilator grates thoroughly. I tried to shake them loose, but they were securely screwed into place. They could not be removed without some time and effort. I examined the floor. It was compact and unbroken cement.

There was one more possibility. The ceiling. Perhaps Henry had some device - some series of hoists - that would whisk, the machine into a ceiling crevice.

I got a step ladder from the other room and went over the ceiling with minute thoroughness. The plaster was old and a bit grimy, but there was not even one crack that might indicate access to some secret compartment above.

I got off the ladder and found myself trembling.

There was no possible way out of this room. None at all.

Except by the time machine!

It was ten minutes before the weakness left me. I turned out the lights and locked both doors behind me.

The next morning I began converting my capital into cash.

Shippler called in the afternoon with his daily report: "Mrs. Reeves attended a card party at the home of this Doris at two yesterday afternoon. I found out her last name. It's Weaver. The names of the twins are..."

"Confound it, I don't care what the names of the blasted twins are."