“I was out of town. Have you done it yet?”
McFarlane shook his head. “Union trouble. The technicians insisted on stopping for coffee.” He looked disgusted.
“You never could adjust to working with human beings, Theo. I’ll be there in twenty minutes.” Garrod broke the connection, ran through the house and out to the garage. He chose the rotary-engined Mercedes two-seater as being the best for a trip around the edge of the city. As he was hurling the little car down the winding shrub-walled road from the house it occurred to him that he had left without speaking to Esther, but then there was nothing to say except that he would get the divorce one way or the other—and that could wait till morning.
During the hectic drive he thought about the implications of the message he had received from McFarlane. In spite of nine years of continuous research, slow glass had retained its integrity in one vital respect—it refused to yield information any sooner than specified by the delay period built into its crystalline structure. A piece of Retardite one year thick retained its stored images for one year, and no amount of coaxing by an army of research workers had persuaded it to do otherwise. Even with its inflexibility in this respect, Retardite had found thousands of applications in every field from costume jewellery to outer planet exploration—but had it been possible to change the delay period in retrospect, to release information at will, then slow glass would truly have come into its own.
The basis of the difficulty was the way in which images were not stored inside the material as images. Variations in the arrangement of light and shade were translated into stress patterns which gradually made their way from one face of the glass to the other. Discovery of this fact had solved one theoretical objection to the Retardite principle. In the early days, when it was thought that the time delay was a function of the thickness of the crystalline material, some physicists had pointed out that images passing through at an angle should have emerged considerably later than images which traversed the material at right angles. To overcome the anomaly it had been necessary to postulate an infinitely high index of refraction for Retardite, a measure which Garrod had instinctively disliked. Subsequently he had found great personal satisfaction in establishing the true nature of the piezoluctic transfer phenomenon, and in seeing it named the Garrod Effect in scientific texts.
Establishing the nature of the effect, however, had not altered the fact that there was no random access to the stored images. If the time delay had been directly related to thickness it might have been possible to split Retardite into thinner sheets and get at the information sooner. As it was, any attempt—no matter how subtle or insidious—to interfere with the crystalline structure resulted in a near-instantaneous relieving of the stress patterns. There was not even a glimmer of released light. The material simply relaxed its grip on the past and became jet black, a vitreous slate awaiting the imprint of new memories.
Although he found it increasingly difficult to put in time in the laboratories Garrod still had a strong personal interest in solving the problem of triggered emission. This sprang partly from his scientist’s possessiveness regarding his own discovery, partly from a vague awareness that there were cases in which slow glass acted as a tantalus cup, torturing individuals whose overwhelming need was for immediate drafts of knowledge. Only recently Garrod had read a newspaper story about a judge who had died a few months after a five-year wait to learn if a man he had sent to the chair would be proved guilty by the piece of slow glass which had been sole witness to the murder. He could not remember the judge’s name, but the reality of his suffering was an unwelcome part of Garrod’s world picture.
Above the thoroughfare along which he was driving, the panels of slow glass glowed with the blue of the daytime sky, creating the effect of speeding through a wide tunnel with rectangular holes cut in the roof. In one of them he glimpsed the silvery dart of an airliner which had flown over the spot earlier in the day.
The night security man saluted from his kiosk as Garrod swung the Mercedes in through the gates of the research and development building. Most of the block was in darkness but McFarlane’s section was ablaze with golden light. Garrod slipped off his jacket and threw it on to a chair as he walked into the laboratory and saw a group of men gathered around one of the benches. The only one not in shirtsleeves was McFarlane himself—as always the research chief was wearing a neat, square-shouldered business suit. It was said that he had not once touched a soldering iron since the day he made management, but his control of what went on in his own department was absolute, and detailed.
“You’re just in time,” McFarlane said, nodding to Garrod. “I’ve a feeling we’re going to connect.”
“You’re still following up on the modified Cerenkov radiation approach?”
“And getting results, too.” McFarlane pointed at a pure black panel of slow glass which was mounted in a frame and surrounded by a complex of grey boxes, oscilloscopes and a lashed-up instrument panel. “That’s a piece of three-day glass which was wiped clean yesterday. The images it picked up since then aren’t due out this side until tomorrow, but I think we’re going to drag ’em through a little faster.”
“How do you know?”
“Look at those diffraction patterns.” McFarlane indicated a display tube. “See how different it is to what we usually get when we shoot X-rays through Retard!te? That shimmering effect shows that the image velocity and the Cerenkov radiation velocity have begun to equalize.”
“Maybe you’ve just slowed down the Cerenkov.”
“I’m betting we’ve speeded up the image.”
“Something wrong here,” one of the technicians remarked in conversational tones. “The distance-over-time curve is starting to look…exponential.”
Garrod examined the oscilloscope trace and thought of light pouring into the panel of slow glass, for perhaps thirty-six hours, now gathering on itself, forming a wave, a peak…
“Cover your eyes,” McFarlane shouted. “Get away from that thing!”
Garrod flung his arm over his face as the technicians stampeded outwards, then there was a silent, bleaching flash of brilliance; a flash which froze movement on punished retinas; a flash which clutched Garrod’s heart because it should have been accompanied by the detonation of a hell-bomb. He lowered his arm and saw the other men only dimly through a screen of green and orange after-images. The slow glass panel was black as night once more, and as peaceful.
McFarlane spoke first, in a subdued voice. “I told you we’d squeeze some light out of that panel—and we sure as hell did.”
“Is everybody all right?” Garrod peered around the group who were slowly converging again on the bench. “Did anybody take it right in the face?”
They shook their heads. “We’re all right, Mr. Garrod.”
“We’ll call it a night then. Book in a full night shift, and give your eyes plenty of time to recover before you drive home.” Garrod turned to McFarlane. “You’ll have to draw up a new set of safety procedures before taking this any further.”
“Don’t I know it!” McFarlane’s eyes looked bruised behind their diminishing lenses. “But we got light, Al. That was the first time in nine solid years of trying that anybody ever modified a Retardite lattice and didn’t simply relieve the stress patterns. We really got light.”
“I’ll say we did.” Garrod picked up his jacket as they walked slowly towards McFarlane’s private office. “You’d better get our patent lawyers on to it first thing in the morning. Are there any talkative types among your boys?”