Minerva‘s sailors pulled his belongings up on ropes: first his chest of alchemical whatnot, and second a box, still partly covered in gaudy wrapping paper. Dappa caught this as it was hoisted over the rail and set it down on a table that they’d brought up from van Hoek’s wardroom. Nestled in crumpled paper inside the box was an egg of fired clay: a flask, stoppered at one end by a wooden bung. Wax had been dribbled over this to seal it, but Enoch Root had already violated the seal so that he could perform his tests. Dappa thrust his hands down into the nest of paper and cupped the egg in his hands and raised it up into cold blue sunlight. Van Hoek drew out his dagger and used its tip to worry the bung loose. When this had been removed, Dappa tipped the flask. Fluid sloshed inside with momentum so potent that it nearly pulled him off his feet. A bead of liquid silver leapt out into the sun and built speed until it struck the tabletop with the impact of a hammer. Then it exploded in a myriad gleaming balls that glided across the table and cascaded over its edge like a waterfall and spattered heavily on Minerva‘s deck. The quicksilver probed downhill, seeking gaps between planks, spattering down into the gundeck and making an argent rain among the men who stood tense by their guns. A murmur and then a thrill ran through the ship. It was to every man aboard as if Minerva had received a second christening, with quicksilver instead of Champagne, and that she was now re-consecrated to a new mission and purpose.
It was high noon before the barge was alongside Minerva and the transfer of cargo could begin. This was an awkward way to do it, but the Japanese officials would on no account suffer Minerva to approach shore. With larger cargo it would have been well nigh impossible. But Minerva was laden with wootz, silk, and pepper, and the barge carried nothing but flasks of quicksilver, and bales of straw for packing it. Any of these items could be passed or thrown from hand to hand, and once they had got it organized the transfer went on at a terrific pace—a hundred men, sweating and breathing hard, could transfer tons of cargo in a minute. Steel, spice, and silk streamed out of Minerva‘s holds and were replaced by quicksilver. The outgoing and incoming flows grazed each other at one place on the upperdeck, where Monsieur Arlanc and Vrej Esphahnian sat at the table facing each other, each armed with a stockpile of quills, one tallying the quicksilver and the other tallying other goods. Every so often they would call out figures to each other, just making sure that the flows were balanced, so that Minerva would not rise too high or sink too low in the water.
Enoch Root emerged, rubbing sleep from his eyes, when the transfer was perhaps two-thirds complete. He flicked his eyes at Jack, and then van Hoek, and then returned to his cabin.
Twenty seconds later Jack and van Hoek were in there with him.
“I was trying to sleep but that lanthorn kept me awake,” Enoch said, nodding at an oil lamp that was suspended from the ceiling of his cabin on a chain. It was swinging back and forth dramatically even though the ship was only rocking slightly from side to side.
“Why don’t you take it down?” Jack asked.
“Because I think it is trying to tell me something,” Enoch said. He then turned his gaze on van Hoek. “You told me, once, that every harbor, depending on its size, has a characteristic wave. You said that even if you were lying in your cabin with the curtains drawn you could tell the difference between Batavia and Cavite simply by the period of the waves.”
“It’s true,” van Hoek said. “Any captain can tell you stories of ships that were proven seaworthy, but that were cast away entering an unfamiliar harbor, because the period of that harbor’s waves happened to match the natural frequency of the ship’s hull.”
“Every ship, depending on how it is ballasted and laden, rocks in a particular rhythm—just as this lantern swings at a fixed rate,” said Enoch, explaining it for Jack. “If waves strike that ship in the same rhythm, then she soon begins moving so violently that she overturns and is cast away.”
“Just as a lute-string that is plucked makes its partner, which is tuned to the same note, vibrate in natural sympathy,” said van Hoek. “Go on, Enoch.”
“When we sailed into this harbor early this morning, my lanthorn suddenly began to swing so violently that it was bashing against the ceiling and spilling oil about the cabin,” Enoch said. “And so I took it down and adjusted the chain to a different length, as you see it now.” Enoch now lifted the lanthorn’s chain from its hook in the ceiling-beam, and began to feel his way along, link by link, until he came to one that was worn smooth. “This is how it was when we entered the harbor,” he said, and then re-hung the lanthorn so that it dangled a few inches lower than before. He pulled it away to the side and then let it go, and it began swinging back and forth in the center of the cabin. “So it follows that the frequency we observe now—swing, swing, swing—is tuned to the natural period of this harbor’s waves.”
“With all due respect to you and your friends of the Royal Society,” van Hoek said, “can this demonstration not wait until we are out in the middle of the Sea of Japan?”
“It cannot,” Enoch said calmly, “because we will never reach the Sea of Japan. This is a death-trap.”
Van Hoek was about to spring to his feet, but Enoch restrained him with a hand on the shoulder, and glanced out his cabin window lest they be observed by some Japanese. “Hold,” he said, “it is a subtle trap and subtle we must be to escape it. Jack, on my bed there is a flask.”
Jack, who was too tall to stand upright in the cabin, crab-walked sideways a step or two, and found one of the quicksilver-flasks nestled among Enoch’s bed-clothes.
“Hold it out at arm’s length,” Enoch said.
Jack did so, though it took the strength of both arms. The quicksilver inside the flask swirled about as he moved it, but then it settled. His hands became still. Then the liquid metal began sloshing back and forth, forcing his hands to move left, right, left, right, no matter how hard he tried to hold it still.
“Mark the lantern,” said Enoch. Attention shifted from the sloshing flask to the swinging light.
Van Hoek saw it first. “They move at the same period.”