"Just a trial run. I sent it back twenty minutes." Although the camera had been pointing at them, the two men were not in the picture. Instead, in darkish pastels due to the failing light, the photograph showed a view down the Avenue, with their parked truck just a tiny square in the distance. From the rear doors of the vehicle the two men could be seen removing the yellow box.
"That's very. impressive," Barker said, shocked into admission of the truth. "How far back can you send it?"
"Seems to be no limit, just depends on the power source. This model has nicad batteries and is good back to about ten thousand B.C."
"And the future?"
"A closed book, I'm afraid. But we may lick that problem yet." He extracted a small notebook from his hip pocket and consulted it, then set the dials once again.
"These are the optimum dates, about the time we figure Stonehenge was built. I'm making this a multiple-shot. This lever records the setting, so now I can feed in another one."
There were over twenty settings to be made, which necessitated a great deal of dial spinning. When it was finally done, Lanning actuated the timer and went to join Barker.
This time the departure of the chronostasis temporal-recorder was much more dramatic. It vanished readily enough, but left a glowing replica of itself behind, a shimmering golden outline easily visible in the growing darkness.
"Is that normal?" Barker asked.
"Yes, but only on the big time jumps. No one is really sure just what it is, but we call it a temporal echo. The current theory that it is sort of a resonance in time caused by the sudden departure of the machine. It fades away in a couple of minutes."
Before the golden glow was completely gone the device itself returned, appearing solidly in place of its spectral echo. Lanning rubbed his hands together, then pressed the print button. The machine clattered in response and extruded a long strip of connected prints.
"Not as good as I expected," Lanning said. "We hit the daytime all right, but there is nothing much going on."
There was enough going on to almost stop Barker's ar-cheologist heart. Picture after picture of the megalith standing strong and complete, the menhirs upright and the lintels in place upon all the sarsen stones.
"Lots of rock," Lanning said, "but no sign of the people who built the thing. Looks like the dating theories are wrong. Do you have any idea when it was put up?"
"Sir J. Norman Lockyer believed that it was erected on June 24th, 1680 B.C.," he said abstractedly, still petrified by the photographs.
"Sounds good to me."
The dials were spun and the machine vanished once again. The picture this time was far more dramatic. A group of men in rough homespun genuflected, arms outstretched, facing toward the camera.
"We've got it now," Lanning chortled, and spun the machine about in a half circle so it faced in the opposite direction. "Whatever they're worshiping is behind the camera. I'll take a shot of it and we'll have a good idea why they built this thing."
The second picture was almost identical to the first, as were two more taken at right angles to the first ones.
"This is crazy," Lanning said, "they're all facing into the camera and bowing. Why, the machine must be sitting on top of whatever they are looking at."
"No, the angle proves that the tripod is on the same level that they are." Sudden realization hit Barker and his jaw sagged. "Is it possible that your temporal echo could be visible in the past as well?"
"Well… I don't see why not. Do you mean.?"
"Correct. The golden glow of the machine caused by all those stops must have been visible on and off for years. It gave me a jolt when I first saw it and it must have been much more impressive to the people then."
"It fits," Lanning said, smiling happily and beginning to repack the machine. "They built Stonehenge around the image of the device sent back to see why they built Stonehenge. That's one problem solved."
"Solved! The problem has just begun. It's a paradox. Which of them, the machine or the monument, came first?"
Slowly, the smile faded from Dr. Lanning's face.
Pull! Pull steadily…!" Dragomir shouted, clutching at the tarry cords of the net. Beside him in the hot darkness Pribislav Polasek grunted as he heaved on the wet strands. The net was invisible in the black water, but the blue light trapped in it rose closer and closer to the surface. "It's slipping…" Pribislav groaned and clutched the rough gunwale of the little boat. For a single instant he could see the blue light on the helmet, a faceplate and the suited body that faded into blackness — then it slipped free of the net. He had just a glimpse of a dark shape before it was gone. "Did you see it?" he asked. "Just before he fell he waved his hand."
"How can I know — the hand moved, it could have been the net, or he might still be alive?" Dragomir had his face bent almost to the glassy surface of the water, but there was nothing more to be seen. "He might be alive."
