“Nice theory,” said Herries. ‘‘I’ve daydreamed myself. But there’s only one main projector, to energize all the subsidiary ones. Building it took almost the whole world supply of certain rare earths. Its capacity is limited. If we started sending military units into the past, it’d be a slow and cumbersome operation—and not being a Security officer, I’m not required to kid myself that Moscow doesn’t know we’ve got time travel. They’ve probably even given Washington a secret ultimatum: ‘Start sending back war material in any quantity, and we’ll hit you with everything we’ve got.’ But evidently they don’t feel strongly enough about our pumping oil on our own territory—or what will one day be our own territory—to make it a, uh, casus belli.”

“Just as we don’t feel their satellite base in the twentieth century is dangerous enough for us to fight about,” said Greenstein, “but I suspect we’re the reason they agreed to make the Moon a neutral zone. Same old standoff.”

“I wonder how long it can last?” murmured Polansky.

“Not much longer,” said Olson. “Read your history. I’ll see you, Greenstein, boy, and raise you two.”

Herries let the shower run about him. At least there was no shortage of hot water. Transoco had sent back a complete atomic pile. But civilization and war still ran on oil, he thought, and oil was desperately short up there.

Time, he reflected, was a paradoxical thing. The scientists had told him it was utterly rigid. Perhaps, though of course it would be a graveyard secret, the cloak-and-dagger boys had tested that theory the hard way, going back into the historical past (it could be done after all, Herries suspected, though by a roundabout route which consumed fabulous amounts of energy) in an attempt to head off the Bolshevik Revolution. It would have failed. Neither past nor future could be changed—-they could only be discovered. Some of Transoco’s men had discovered death, an eon before they were born…But there would not be such a shortage of oil up in the future if Transoco had not gone back and drained it in the past. A self-causing future—

Primordial stuff, petroleum. Hoyle’s idea seemed to be right, it had not been formed by rotting dinosaurs but was present from the beginning. It was the stuff which had stuck the planets together.

And, Herries thought, was sticking to him now. He reached for the soap.

* * *

Earth spun gloomily through hours, and morning crept over wide brown waters. There was no real day as men understood day—the heavens were a leaden sheet with dirty black rainclouds scudding below the permanent fog layers.

Herries was up early, for there was a shipment scheduled. He came out of the bosses’ messhall and stood for a moment looking over the mud beach and the few square miles of cleared land, sleazy buildings and gaunt derricks inside an electric mesh fence. Automation replaced thousands of workers, so that five hundred men were enough to handle everything, but still the compound was the merest scratch and the jungle remained a terrifying black wall. Not that the trees were so utterly alien—besides the archaic grotesqueries, like ferns and mosses of gruesome size, there were cycad, redwood, and gingko, scattered prototypes of oak and willow and birch. But Herries missed wild flowers.