Symonds was already present. He popped rabbit-like out of the building, a coded manifest in one hand a pencil behind his ear: “Good morning, Mr. Herries,” he said. His tone gave its usual impression of stiff self-importance.

“ ’Morning. All set in there?” Herries went in to see for himself. A spatter of rain began to fall, noisy on the metal roof. The technicians were at their posts and reported clear. Outside, one by one, the rest of the men were drifting up. This was mail day, and little work would be done for the remainder of it.

Herries laid the sack of letters to the future inside the shed in its proper spot. His chronometer said one minute to go. “Stand by!” At the precise time, there was a dim whistle in the air and an obscure pulsing glow. Meters came to life. The pumps began to throb, driving crude oil through a pipe which faced open-ended into the shed. Nothing emerged that Herries could see. Good. Everything in order. The other end of the pipe was a hundred million years in the future. The mail sack vanished with a small puff, as air rushed in where it had waited. Herries went back outside.

“Ah…excuse me.”

He turned around, with a jerkiness that told him his nerves were half unraveled. “Yes?” he snapped.

“May I see you a moment?” asked Symonds. “Alone?” And the pale eyes behind the glasses said it was not a request but an order.

Herries nodded curtly, swore at the men for hanging around idle when the return shipment wasn’t due for hours, and led the way to a porch tacked onto one side of the transceiving station. There were some camp stools beneath it. Symonds hitched up his khakis as if they were a business suit and sat primly down, his thin hands flat on his knees.

“A special shipment is due today,” Symonds said. “I was not permitted to discuss it until the last moment.”

Herries curled his mouth. “Go tell Security that the Kremlin won’t be built for a hundred million years. Maybe they haven’t heard.”

“What no one knew, no one could put into a letter home.”

“The mail is censored anyway. Our friends and relatives think we’re working somewhere in Asia.” Herries spat into the mud and said: “And in another year the first lot of recruits are due home. Plan to shoot them as they emerge, so they can’t possibly talk in their sleep?”

Symonds seemed too humorless even to recognize sarcasm. He pursed his lips and declared: “Some secrets need be kept for a few months only; but within that period, they must be kept.”

“Okay, okay. Let’s hear what’s coming today.”

“I am not allowed to tell you that. But about half the total tonnage will be crates marked Top Secret. These are to remain in the shed, guarded night and day by armed men.” Symonds pulled a slip of paper from his jacket. “These men will be assigned to that duty, each one taking eight hours a week.”