“Most interesting.” The detective began to stuff a big-bowled pipe. “Like mercury vapor, what?”

“So Rotherhithe placed that box in the grave, did he?” muttered the inspector.

“Don’t be ridiculous!” snapped the detective. “I have three lines of conclusive proof that Rotherhithe is entirely innocent. What puzzled me was the actual cause of his lordship’s death. But if, as this gentleman says, there happened to be a deadly poison buried in that mound…to discourage grave-robbers? I wonder, though, how the old Saxons came by an American mineral. Perhaps there is something to these theories about early Phoenician voyages across the Atlantic. I have done a little research on a notion of mine that there are Chaldean elements in the Cornish language, and this seems to bear me out.”

Everard felt guilty about what he was doing to the science of archaeology. Oh, well, this box was going to be dumped in the Channel and forgotten. He and Whitcomb made an excuse to leave as soon as possible.

On the way back to London, when they were safely alone in their compartment, the Englishman took out a moldering fragment of wood. “Slipped this into my pocket at the barrow,” he said. “It’ll help us date the thing. Hand me that radiocarbon counter, will you?” He popped the wood into the device, turned some knobs, and read off the answer. “One thousand, four hundred and thirty years, plus or minus about ten. The mound went up around…um…A.D. 464, then, when the Jutes were just getting established in Kent.”

“If those ingots are still that hellish after so long,” murmured Everard, “I wonder what they were like originally? Hard to see how you could have that much activity with such a long half-life, but then, up in the future they can do things with the atom my period hasn’t dreamed of.”

Turning in their report to Mainwethering, they spent a day sight-seeing while he sent messages across time and activated the great machine of the Patrol. Everard was interested in Victorian London, almost captivated in spite of the grime and poverty. Whitcomb got a faraway look in his eyes. “I’d like to have lived here,” he said.

“Yeah? With their medicine and dentistry?”

“And no bombs falling.” Whitcomb’s answer held a defiance.

Mainwethering had arrangements made when they returned to his office. Puffing a cigar, he strode up and down, pudgy hands clasped behind his tailcoat, and rattled off the story.

“Metal been identified with high probability. Isotopic fuel from around the thirtieth century. Checkup reveals that a merchant from the Ing Empire was visiting year 2987 to barter his raw materials for their synthrope, secret of which had been lost in the Interregnum. Naturally, he took precautions, tried to pass himself off as a trader from the Saturnian System, but nevertheless disappeared. So did his time shuttle. Presumably someone in 2987 found out what he was and murdered him for his machine. Patrol notified, but no trace of machine. Finally recovered from fifth-century England by two Patrolmen named, haw! Everard and Whitcomb.”