Pattern of Murder
Page 17
“This is bad enough to bring down the whole cinema, never mind a houselight,” Turner commented at length. “I don’t see that we’re proving anything, either. This noise wasn’t going on when the houselight fell.”
“Of itself, the noise means nothing, and does nothing,” Sid answered. “It is caused by the extreme variations of light striking the photo-electric cell as the scratches pass over it in varying thickness and designs. There! Hear that bump? That is the joint Billy made after Terry snapped the film.... Now it was a little after this point that the trouble started. I want to see if it’s possible to get through this film without anything unusual happening. If the design is again reproduced in the sand up there on the still case, I—”
Sid broke off and jerked his face upwards. Turner did the same. To both of them there had come the distinct sound of splintering glass. They were just in time to see the two big new houselight bulbs nearest to them, at the very back of the Circle, splinter into a pass of fragments and leave bare filaments.
Sid leapt up. “See that?” he demanded. “Did you see it?”
Turner was looking mystified. “Of course I saw it! Two lamps gone west!”
“It means something much more exciting than that, sir.” Sid stubbed out his cigarette and raced out of the Circle.
After a moment or two the shattering din from the screen speakers ceased and the picture vanished. Sid returned at a run. Without looking at Turner, who was contemplating the two shattered houselight bulbs, he hurried across to the ladder against the wall and climbed the rungs swiftly.
“We’ve got it, sir!” he shouted. “Exactly the same design again! Come and look!”
Turner hurried to the ladder, mounted it, and standing two rungs below Sid he gazed at the incredible intricacy of the design that had been traced in the sand.
“Yes, that looks like it right enough,” he admitted. “But I must say I’m utterly at sea.”
He climbed down the ladder again and stood pondering as Sid got busy with the fire bucket, swept the sand from the top of the case back into it, and then descended to the floor. He returned the bucket to its normal position and then looked up at the shattered bulbs.
“There’s no doubt any more, sir, that we’re dealing with ultrasonics,” he commented. “Inaudible sound in the form of pure vibration.”
“Inaudible!” Turner echoed. “But that infernal row we’ve been listening to would wake the dead!”
“That had nothing to do with it,” Sid insisted. “That is what I meant when I said the noise counted for nothing. You see, an ultrasonic wave is in a different class to plain noise. It operates far above normal sound, and for that reason normal sound cannot affect it.”
“Oh!” Turner was baffled, but tried not to show it.
Sid went on, “Another thing is pretty obvious, too. At the height where these houselights hang—and above them, which includes the top of the still-case—an ultrasonic wave was going full blast whilst that Travelogue was running. It comes from the screen, speakers. It affected those two hanging bulbs we fitted recently and smashed their glass to bits—just the kind of glass that would smash too under ultrasonic vibration.”
“Maybe, but only one houselight came down—the one which killed Vera,” Turner pointed out. “The one on the left here—and then it wasn’t the whole globe. Only the lower hemisphere.”
“Yes....” Sid thought for a moment. “And that hemisphere must have dropped in one piece, not in fragments, otherwise it would not have hit Vera with the terrific force intended. It broke when it did hit her, of course, but that isn’t the point. The twin houselight on the right wasn’t affected, even though it must have been in the range of the vibration. In any case, I don’t think a supersonic wave would have been able to smash those opal globes. They’re thick and solid, just a bulb has glass which is thin and brittle.”
“Certainly that lower hemisphere came down in one piece,” Turner said. “Witnesses at the inquest testified to the fact. The assumption was that the screws had contracted too much owing to the ventilator draught, or something. Remember?”
“Yes.... Yes, I remember.”
Turner fondled his chin. “How in the name of sanity does that Travelogue produce an ultrasonic vibration? Is it by accident, a flaw in the recording, or what?”
“It can’t be a flaw in the recording, sir, otherwise it would not have been necessary for Terry to ruin the track afterwards. He did that with the obvious intention of making the film useless, so it would be converted into scrap and destroy the evidence. The fact remains that an ultrasonic vibration is produced, but I can’t fathom how.”
“To me,” Turner said presently, “there is another problem just as big. How did an ultrasonic wave bring down the lower hemisphere of that globe? It couldn’t, could it?”
“The original fixture is in the winding room—where we put all of them after we’d taken them down. We might do worse than take a look at them.”
Turner nodded and followed Sid upstairs. From a corner of the winding room Sid finally dragged out the massive old fixture they wanted. It was a complete globe, for after the accident a spare lower hemisphere opal had been fitted—the one indeed with which Terry had originally experimented—until the new houselight fixtures had arrived. The fact that the opal was slightly duller in texture than all the others made it easily identifiable.... In the bright light Sid examined the turnscrews, turning them back and forth on their threads with Turner watching over his shoulder.
“They’re mighty slack,” Sid commented, frowning. “A mere touch moves them along the threads. First time I’ve thought of examining them. Terry himself took care to fit a new hemisphere so I didn’t have the chance to spot anything. Not that I had any suspicions at the time, anyway.”
From the corner he hauled up two more of the globes and tested the screws. By comparison they were stiff. Grimness slowly settled on Turner’s face.
“It looks to me,” he said, “as though the screws on that particular lamp have been turned back and forth so that they move without difficulty. The experts must have noticed that also, but evidently they didn’t attach much importance to it.”
“Probably because they didn’t compare them with the tightness of the screws on the other lamps,” Sid said. “I’ll tell you what I think we should do, even though it may take a bit of time. The winches and cables are still in place in the false roof. I think I’ll haul this lamp back in position with the screw points only just holding the hemisphere in place. Then I’ll run the Travelogue again and see what happens.”
“Right! I’ll help you.”
Turner pulled off his raincoat and the jacket of his evening suit, then he and Sid got busy.... In fifteen minutes they were in the Circle again, watching the hanging globe earnestly as the noisy film was run through, without vision, from the grey screen. Almost after the same period as before, when the bulbs had broken, the lower hemisphere abruptly detached itself from its screw fittings and dropped downwards. It struck the floor immediately beneath the tip-up seat, bounced, and rolled to a standstill on the thick carpet.
Turner sat in silence for a moment; then he looked at Sid.
“That’s it!” Sid muttered. “We’ve got the answer! The screws were loosened beforehand by Terry—to the danger point—and as long as no supersonic vibration took place the globe was okay. He knew that. The Travelogue film he ‘prepared’ in some way to make it produce the inaudible vibration. He was all set, then when I noticed that Helen and not Vera was on the tip-up seat he tried to stop the show, or at least delay it, by snapping the film. I insisted that he carry on. He did so because Vera had come back. After a while the inaudible vibration shifted the screws back along the grooves and....”
Turner stared at the globe hemisphere on the carpet. He seemed incapable of saying anything. Sid went on talking, recapitulating pensively.
“On the two nights he supposedly fixed his machine he was probably making tests. He must have doctored the film on the Friday n
ight after it had had its evening run. He knew there would only be a kid’s matinee on Saturday afternoon, so the Travelogue would not be used until the Saturday night, when the trouble happened. After that, the film would be taken away and, he hoped, destroyed because of its condition.”
“It seems incredible,” Turner whispered. “No one but a madman would think up such a fiendish idea!”
“I found a sliver of glass, too,” Sid added presently. “I think it came from a tumbler missing from the washroom. I’ll bet he used it to test whereabouts the ultrasonic vibration was striking. He overlooked one thing, however: ultrasonic vibrations make patterns, and that one in the dust on the still-case started me off, together with the fact that two screws had been mysteriously pushed from one end of the case top to the other.... Yes, we know how he did it, but we still have to find out what he did to that film.”
“Let’s have another look at it,” Turner said curtly.
They went back upstairs and Sid removed the film from the projector after switching the machine off. Without a word he went down into the winding room with Turner behind him. Tossing the free end of the film on to an empty spool Sid fixed the loaded spool on the opposite winder. The film lay bright and clear under the strong electric light.
“You can see the markings quite distinctly,” Sid said, handing Turner his pocket lens. “Take a look.”
Turner bent over the film, winding it slowly from one spool to the other. After a long study he straightened up and frowned.
“Yes, the scratchings are plain enough,” he agreed, “but what about those little pin holes at the side? Very, very tiny, like dots. That normal?”
“No, not exactly. Emulsion bubbles that haven’t dried out properly in the printing. We often get them and they sometimes case a hum in the sound gate. In this case that didn’t happen because, before the film was ruined, there was no trace of hum.”
“Emulsion. Bubbles...,” Turner repeated slowly. “In that case you mean that the emulsion has settled in minute bubbles?”
“Right.”
“But surely they would be on the emulsion side of the film? These dots go right through the film. They’re holes!”
Sid’s expression changed. “Holes? Holes? Here, let me see!”
He nearly snatched the lens from Turner’s fingers and peered at the film earnestly, edging it along inch by inch. Finally he lowered his hands and stared fixedly in front of him.
“You’re right, sir—dead right!” he breathed. “When I examined this film at home the light wasn’t too good: there’s a tree, which keeps the light off the woodshed where I do most of my tinkering. When I saw the dots I assumed they were emulsion bubbles. I got no bright edgewise light on the reverse side, as I have now, otherwise I’d have seen these holes.... Hell, but this makes a world of difference! No film ever got like this in the ordinary way. These holes are as deliberate as the scratching of the sound track.”
Sid frowned and put the lens back in his pocket. “Even now I don’t see how it could produce an ultrasonic vibration. Seems to me there would be just a high-pitched hum and nothing more. Unless the speed of the film’s transit has something to do with it. In the matter of sound mechanics Terry has a far greater knowledge than I.”
“So it seems,” Turner commented bitterly. “Of all the devilish ideas, this about takes the biscuit—”
“Tell you what!” Sid snapped his fingers suddenly. “There’s one man who can make rings round Terry when it comes to sound mechanics, and that’s Cliff Dixon, our service engineer. What is more, he has all kinds of instruments for testing, which we haven’t got.”
“Yes, you’re right there,” Turner made the admission slowly, as he reflected. “He might be able to give us the answer, but he wouldn’t be human if he didn’t want to know the reason. What do we tell him?”
“The truth. We’re battening down on a murderer, so why should we hide anything? Cliff’s a reasonable chap: he’ll keep his mouth shut if we ask him to.”
Turner glanced at his watch. “Half past twelve. He’s used to being called on emergencies, so I’ll see if I can get him. I’ll make the excuse that we have sound trouble and are working late. I’ll go and give him a ring.”
Sid nodded and began to rewind the film back to the start. He took it upstairs and relaced it into the projector. Then he stood with his fists clenched.
“Filthy, murdering devil,” he whispered. “I’ll get him for this if it’s the last thing I do! The law will hang him, but not before I’ve put in my two cents’ worth! He didn’t give Vera a chance, and I shan’t give him any. Damned if I will!”
He gave a start as the interphone buzzed. He picked up the instrument and Turner’s voice came from the office below.
“He’s coming, Sid. Be here in about ten minutes. I’ll wait down here so I can let him in. Get the film ready.”
“It’s done, sir. Let me know when he gets here.”
“I will.”
Sid put the instrument back on its rest and mooched about the box, hands in trouser pockets, brows down. All the bitter unhappiness, which he had felt at the death of Vera had returned to him. Whatever she had been he had loved her. Probably he was the only person who ever had—and she had been brutally murdered by a brilliant trick of ultrasonics.
“Right, Terry, you just wait! You just wait....” Sid beat the wall gently with his massive fist; then very slowly he relaxed and covered his face with his hands. He sat down on the heavy bench and brooded until the interphone again buzzed. It was Turner.
“Cliff’s got here now, Sid, and I’ve been explaining things to him. Naturally he’ll co-operate. Start up the reel and join us in the Circle.”
“Okay, sir.”
Sid rang off, waited until he saw Turner and the service engineer come into the Circle, and then he started the machine and went out to join them. Cliff Dixon was a short, snub-nosed man with red hair. Superficially, he appeared to have no particular qualifications until one came to the subject of sound and sound projectors—then it would have been hard to find a man anywhere with such far reaching knowledge.
As Sid appeared Dixon merely looked up once and nodded an acknowledgement; then he turned his attention back to the instrument he was adjusting. Sid recognized what it was. It had the appearance of a voltmeter with sensitive bright nodules projecting from its polished circular exterior.
“Frequency detector?” Sid questioned.
“Yes.” Cliff Dixon did not look up.
He finally got the instrument adjusted to his liking, then from the case he had brought with him he took out a series of short lengths of rod, rather like the canes of a sweep’s brush but much smaller—and screwed one length into the other until he had a twenty foot extension with the detector screwed on to the topmost rod.
With the extension in his hand, the detector itself waving around the two houselights—one of the old type and one of the new—he began to walk about. In silence Sid and Turner watched him.
“I don’t get the idea,” Turner said, puzzled. “Sure he knows what he’s doing, Sid?”
“There couldn’t be anything surer than that, sir. The detector works like a stopwatch. It registers sound frequencies and the needle automatically stops at the highest recording it can make. They use those things in new cinemas for testing the vibration of sound in different parts of the building. If there is something supersonic that gadget will find it fast enough.”
Only when the film came to an end did Dixon stop his perambulations and lower his instrument carefully. When he had unscrewed it and studied it he gave a whistle.
“Hell’s bells!” he exclaimed, startled. “There is a frequency of ninety thousand vibrations a second registered here!”
“You mean—ultrasonic?” Sid demanded.
Cliff Dixon stared at him. “Man alive, I’ll say it is! The highest most human beings can hear is eighteen thousand vibrations a second, which is about the upper limit of a full symphony orchestra.”
“
After which it becomes so high that it’s inaudible and changes to pure vibration?” Turner asked earnestly.
“That’s right,” the engineer agreed. “Ninety thousand is definitely ultrasonic, but in these scientific days that isn’t really very high. It may interest you to know that there are generators in use, specially made, which turn out an ultrasonic vibration of twelve million to the second. Used for testing flaws in steel and all that kind of thing. Just the same,” Dixon went on, thinking, “this is definitely clever. Seems to bear out what you’ve been telling me, Mr. Turner.”
“Am I right in thinking that this ultrasonic vibration would not be affected by the rattle and clash of that sound track we heard just now?” Sid asked.
“Quite right. That makes no difference. Nothing can alter the fact that the film you ran emits ninety thousand vibrations a second. Noise has nothing to do with it.... Let’s take a look at that film. I’m fascinated.”
Sid nodded and led the way upstairs. In a few minutes he had stopped the racing projector and brought the film into the winding room. Dixon looked at it minutely in the bright light.
“This,” he said finally, “if we forget everything else for the moment, is the work of a genius. You can see what’s happened, can’t you?”
“Matter of fact, no,” Sid growled. “All I can see are a lot of small punctures which should produce a hum on the sound equipment.”
“Hum be damned—” the engineer retorted. “To create a hum those punctures would need to be more widely spaced. Actually they are so close that they’re almost touching. They seem to have been deliberately made with some kind of fine-toothed wheel. The effect in the sound gate is for these dots to produce persistence of vibration—and extremely high, thin note far above hearing range and in the ultrasonic scale. Result—ninety thousand vibrations a second. Finale—a falling globe from which the screws unravelled.”
Silence. Sid stood with his hands pushed deep in his trouser pockets, his eyes on the film. Turner wandered across to his jacket and pulled it on slowly.