“The commissioner?”
Burton glared. “You’ve a lousy sense of humour. No, that was Clifford Webb, and he wants me to call on him.”
“Perhaps he wants to confess?” the sergeant suggested.
* * * *
Clifford Webb was a head taller than Burton, a rangy man with a sharply-pointed nose and eyes that never quite seemed to focus in one place. He was wearing a white laboratory coat as he greeted the inspector.
“Nice of you to spare the time, inspector. Can I offer you a drink?”
“Thanks, no.”
Webb grinned sardonically.
“Could be you object to drinking with a murderer!”
Burton refused to be drawn. Looking round the comfort-ably furnished room, he asked: “What did you want to see me about?”
Webb waved him to a chair, then moved across to the fireplace. His eyes focused briefly on Burton’s face.
“As I understand the law,” he said, “now that I have been acquitted of Laver’s murder, I cannot again be charged with that crime. Correct?”
Burton nodded.
“Good! Now, inspector, prepare yourself for a shock. I did kill Gerald Laver—and I’ll tell you how.”
Burton took a cigarette from his case and lit it. “Just why are you telling me this?” he asked, bluntly.
“Vanity, inspector, pure vanity. I have committed the perfect crime. Naturally, I want you to know—now that you can’t do a damn thing about it! I thought you might have guessed from the title of the paper I read to the Royal Society. Remember? It was called Thermodynamics for a Space-Time Continuum. Time, inspector, that’s the clue you missed....
“Time is an imperfectly understood medium. Perhaps dimension would be a better word. The fourth dimension, it is usually called. An object can have its position in space fixed by the dimensions of length, breadth, and depth—but unless we say that it exists in this space for a certain time, how can we say that its position is fixed at all?”
Burton declined to answer.
“I have long desired to experiment with the dimension of time, to travel through the fourth dimension as we now travel through space, and it was Laver who gave me the opportunity. He advanced the money for my experiments. He wanted a machine that would travel into the past, thinking by this means to cheat death and attain immortality! He did not realise that such a transference would automatically set up a new future for himself, involving a new death.
“For myself, I was interested in the practical applications for crime. Not that I have any interest in crime, as such, but scientific research costs money, and I saw the chance of getting that money. For instance, I could retreat into the past, commit a robbery, then return to the present and fix an unbreakable alibi. Interested, inspector?”
Burton nodded, shredding the end of his cigarette with his teeth.
“I succeeded,” Clifford Webb continued. “I built my machine, and now, if you will follow us, I’ll show it to you. But don’t expect anything spectacular—this isn’t Hollywood.”
Burton followed the physicist through a door and along a passage to the laboratory. In the centre of the room, he saw a doorframe surrounded by the coils of wire helices. A control panel was marked off in an elaborate time-scale.
“Doesn’t look much, does it, inspector? But I can assure you it works.”
Burton looked at Webb, and knew that if he wasn’t dealing with a madman then he was with a murderer.
“How?” he grunted.
“The maths involved are of a very high order,” Webb said, “so you must be content with analogies. When I pass an electric current through my helices, a field of energy is created which distorts the space-time continuum. Space as well as time, you will note. In effect, I can step through my door frame into another time and arrive at a different location from this room!
“I still don’t see how you faked your alibi,” Burton grunted.
“But it’s so simple, inspector. I had already decided to kill Laver—he was threatening to foreclose on his loan. I attended the Royal Society, arriving back here about half-past ten. I adjusted the time-scale of my machine to nine-twenty, the space location to Laver’s study. Then I stepped through.”
Webb’s eyes glittered, his breath quickened.
“As I expected, I was in Gerald Laver’s study—and he was taken completely by surprise. I shot him, phoned the police, and returned here. I had only to wait for you to prove my alibi!”
“I still don’t see how you could be in two places at once,” Burton said.
“How can I explain it? Time is not like a river flowing in one direction. Think of it as a tapestry; the flow of time corresponds to the warp, the lengthwise threads—but there is also the woof, the crosswise threads. These represent our position in the time-stream—and note please that the warp has infinite threads. Perhaps you can imagine it as a series of parallel worlds; we have a possible existence in each, but are only aware of one! I killed Laver in another world, on a different warp of the tapestry...things might have gone wrong, I admit. When I returned, Laver might not have died in this world. My interference with time could have upset my alibi. Perhaps I would have been stranded in that space-time where I killed Laver. Anything might have happened, but I was lucky and it worked out the way I planned.”
Burton threw away the butt of his cigarette. “And now that you’ve been acquitted, you are perfectly safe,” he said, slowly. “Yes, you’re right—it is a perfect crime.”
Webb smiled complacently.
“Perhaps you’d like to see a demonstration, inspector?”
Burton nodded, and the physicist switched on the power and made an adjustment to the time-scale. The helices began to glow and, between the limits of the doorframe, appeared a blackness so intense that the Inspector could not bear to look into it.
Webb removed a white rabbit from a hutch on his work bench.
“Daisy,” he said, smoothing back the rabbit’s long ears, “is the world’s most experienced time-traveller. I’ve used her for many experiments and she has always returned unharmed. I doubt if she knows what a remarkable rabbit she is!”
Burton stared, remembering his sergeant’s story. The hairs at the nape of his neck began to bristle.
“I am sending her back to a period a little after the time of the murder,” Webb said, “the location as before—Laver’s study. Perhaps one of your men reported seeing Daisy? In which case, we mustn’t disappoint him....” He set Daisy on the floor before the door into time and gently urged her through it. Instantly, she vanished from view.
Burton walked warily round the door in the centre of the room. He completed a full circuit without seeing anything of Daisy.
“Convinced, inspector? She will appear again in one minute—I have set the automatic control for that period.”
The seconds ticked by. Burton studied the time-scale carefully; a plan was shaping in his head, a plan to bring Clifford Webb to justice.
“Here she is, inspector!” the physicist exclaimed triumphantly.
He lifted the rabbit from the floor and placed her back inside her hutch.
Burton moved silently and, as Webb turned from the hutch, swung his fist to the physicist’s jaw. Webb slumped unconscious to the floor.
Burton studied the controlling mechanism of the time machine yet again. It seemed simple enough. He adjusted the time-scale for nine-twenty of the night of the murder. Webb had already