Chapter 731

"He also noted that the vibration weakened when ice covered the water in winter, then returned to normal after the ice receded in summer," Cassandra continued, reading on. "He believed some structure on the seabed was responding to changes in the Ley Lines, but he couldn't determine whether it was natural or man-made."

"That means the structure has existed since at least 1847, and it's been operating continuously," Harry said. "Its signal was just too weak and its frequency too low for earlier monitoring networks to detect."

That evening, they ate dinner around the table at the liaison station. Anaka had prepared stewed sea fish with potatoes and hard bread.

Marcus was organizing the day's data, while Isabelle wrote a briefing. Harry and Cassandra sat by the window, each holding a cup of hot tea.

"The structure here in Greenland is older than the ones in Finland," Cassandra said, setting down her cup. "The Norse settled Greenland between the tenth and fifteenth centuries. If they built or activated that structure during that period, it's been running for at least five hundred years."

"Five hundred years of continuous operation." Harry looked out at the icebergs. "If it's been responding to changes in the Ley Lines all that time, it may have become fully integrated with the surrounding Ley Line network. Unlike the structures in Norway and Finland, which are still being activated and adjusted."

"That fits its signal profile. Low frequency, long cycle, steady and continuous, with no interruptions or fluctuations," Cassandra said. "As if it's reached some kind of equilibrium."

The next morning, they returned to the headland. It was colder than the day before, and several more icebergs dotted the sea, drifting slowly south.

Harry crouched at the edge of the rock and pressed his palm against it again,