Farica nodded and went to the desk, where she recorded Nasuada’s instructions on a parchment scroll. That skill alone made her invaluable. Farica asked, “Where can I find him?”

“One of the work gangs in the quarry.”

“Yes, Ma’am. Oh, while you were occupied, King Orrin asked that you join him in his laboratory.”

“What has he done in there now, blind himself?” Nasuada washed her wrists and neck with lavender water, then checked her hair in the mirror of polished silver that Orrin had given her and tugged on her overgown until the sleeves were straight.

Satisfied with her appearance, she swept out of her chambers with Farica in tow. The sun was so bright today that no torches were needed to illuminate the inside of Borromeo Castle, nor could their added warmth have been tolerated. Shafts of light fell through the crossletted arrow slits and glowed upon the inner wall of the corridor, striping the air with bars of golden dust at regular intervals. Nasuada looked out one embrasure toward the barbican, where thirty or so of Orrin’s orange-clad cavalry soldiers were setting forth on another of their ceaseless rounds of patrols in the countryside surrounding Aberon.

Not that they could do much good if Galbatorix decided to attack us himself,she thought bitterly. Their only protection against that was Galbatorix’s pride and, she hoped, his fear of Eragon. All leaders were aware of the risk of usurpation, but usurpers themselves were doubly afraid of the threat that a single determined individual could pose. Nasuada knew that she was playing an exceedingly dangerous game with the most powerful madman in Alagaësia. If she misjudged how far she could push him, she and the rest of the Varden would be destroyed, along with any hope of ending Galbatorix’s reign.

The clean smell of the castle reminded her of the times she had stayed there as a child, back when Orrin’s father, King Larkin, still ruled. She never saw much of Orrin then. He was five years older than her and already occupied with his duties as a prince. Nowadays, though, she often felt as if she were the elder one.

At the door to Orrin’s laboratory, she had to stop and wait for his bodyguards, who were always posted outside, to announce her presence to the king. Soon Orrin’s voice boomed out into the stairwell: “Lady Nasuada! I’m so glad you came. I have something to show you.”

Mentally bracing herself, she entered the laboratory with Farica. A maze of tables laden with a fantastic array of alembics, beakers, and retorts confronted them, like a glass thicket waiting to snag their dresses on any one of its myriad fragile branches. The heavy odor of metallic vapors made Nasuada’s eyes water. Lifting their hems off the floor, she and Farica wended their way in single file toward the back of the room, past hourglasses and scales, arcane tomes bound with black iron, dwarven astrolabes, and piles of phosphorescent crystal prisms that produced fitful blue flashes.

They met Orrin by a marble-topped bench, where he stirred a crucible of quicksilver with a glass tube that was closed at one end, open at the other, and must have measured at least three feet in length, although it was only a quarter of an inch thick.

“Sire,” said Nasuada. As befitted one of equal rank to the king, she remained upright while Farica curtsied. “You seem to have recovered from the explosion last week.”

Orrin grimaced good-naturedly. “I learned that it’s not wise to combine phosphorus and water in an enclosed space. The result can be quite violent.”

“Has all of your hearing returned?”

“Not entirely, but . . .” Grinning like a boy with his first dagger, he lit a taper with the coals from a brazier, which she could not fathom how he endured in the stifling weather, carried the flaming brand back to the bench, and used it to start a pipe packed with cardus weed.

“I didn’t know that you smoked.”

“I don’t really,” he confessed, “except that I found that since my eardrum hasn’t completely sealed up yet, I can do this. . . .” Drawing on the pipe, he puffed out his cheeks until a tendril of smoke issued from his left ear, like a snake leaving its den, and coiled up the side of his head. It was so unexpected, Nasuada burst out laughing, and after a moment, Orrin joined her, releasing a plume of smoke from his mouth. “It’s the most peculiar sensation,” he confided. “Tickles like crazy on the way out.”

Growing serious again, Nasuada asked, “Was there something else that you wished to discuss with me, Sire?”

He snapped his fingers. “Of course.” Dipping his long glass tube in the crucible, he filled it with quicksilver, then capped the open end with one finger and showed the whole thing to her. “Would you agree that the only thing in this tube is quicksilver?”

“I would.”Is this why he wanted to see me?

“And what about now?” With a quick movement, he inverted the tube and planted the open end inside the crucible, removing his finger. Instead of all pouring out, as Nasuada expected, the quicksilver in the tube dropped about halfway, then stopped and held its position. Orrin pointed to the empty section above the suspended metal. He asked, “What occupies that space?”

“It must be air,” asserted Nasuada.

Orrin grinned and shook his head. “If that were true, how would the air bypass the quicksilver or diffuse through the glass? No routes are available by which the atmosphere can gain admission.” He gestured at Farica. “What’s your opinion, maid?”

Farica stared at the tube, then shrugged and said, “It can’t be nothing, Sire.”