Ashfall posted a notice that Steward Lu would inspect Furnace Two before the afternoon batch. The hall filled early with clerks, apprentices, and junior disciples hoping to watch Zhao Heng demonstrate a stronger medicine yield.
Yan’s assignment was to move empty jars and keep the disposal cart clear of the route. He kept his stitched right arm close to his body and carried the jars with his left. The cut was healing, but the upper-arm skin still pulled when he reached too far. He set each jar down instead of stacking them high.
Qinghe was in the hall checking a crate of clinic herbs when Yan noticed the demonstration tray. It carried a batch number he recognized from a previous reject run. He checked it twice. The tagged batch had been marked for a routine yield test, not a repair trial. The pressure needle above the furnace chamber trembled, though the mark beside it said the gauge was due for service.
A line of workers carried small trays through the hall. Yan moved his empty jars to the side wall and left the disposal cart open for cracked containers. The inspection crowd pressed close to the demonstration table; several apprentices stood on the bottom rung of a stair to see over the clerks.
The service gauge had a red paint mark at its safe line. Yan watched the needle tremble above it, fall a little, then jump past it again. The movement was too sharp to be a steady pressure reading. He checked the glass for a hairline crack but saw only the shiver of the pointer.
Yan told the nearest assistant, “That needle is moving above the safe line.”
The assistant tapped the glass. The needle quivered again. “It has been unreliable for a month. Zhao knows.”
“Did the service crew mark it?”
“There’s the red seal on the base.”
Yan looked underneath the dial. A strip of red paper was folded around the mount, stamped “SERVICE DUE.” The end had been tucked behind the bracket. “That mark is still here.”
“The new gauge didn’t arrive.” The assistant lowered his voice. “If I stop the trial, Zhao will say I embarrassed him in front of Steward Lu.”
“If the seam fails, the demonstration ends anyway.” Yan nodded toward the scorch line. “Did the replacement arrive?”
“No. The steward’s inspection is the reason we haven’t installed it. They want to show the old gauge before it’s replaced.”
Yan looked at the line. A thin scorch mark ran along the vessel seam beneath it. He pointed it out. “The casing is hot at the seam.”
The assistant pressed a cloth to the outer rim, then pulled his hand back. “It may be from the last batch.”
“Then check the service mark. If the gauge is wrong, the pressure reading may be wrong too.”
Zhao was focused on the demonstration and had already begun explaining the expected yield to Steward Lu. He showed the clerks the labeled tray and described how the stronger medicine should settle after heating. The crowd listened, and a few apprentices leaned closer to see the color through the glass.
Yan did not interrupt the account. He waited until the assistant tried to silence the needle by tapping the glass again. The glass made a thin sound. The needle jumped, then settled above the red line. “It’s still trembling,” Yan said.
The assistant glanced toward Zhao. “He told us to let the batch continue.”
“Did he say to ignore the service mark?”
“No.”
“Then ask for the replacement gauge.”
The assistant hesitated. “I don’t want to be the one who delays the demonstration.”
Yan kept his voice level. “I’m not arguing about the yield. I’m asking whether the pressure is safe.”
The assistant looked at the seam again. The scorch line had lengthened by the width of a fingernail. “I’ll ask.”
He approached Zhao and spoke low. Zhao’s face tightened. “The process is stable. The gauge has always trembled.”
Yan remained by the empty jars. “The needle is past the marked line, and the casing has a new scorch mark.”
Steward Lu turned from the demonstration. “How long has the gauge been due for service?”
“A month,” the assistant replied.
“Why has it not been replaced?”
“The storehouse has not sent the part.”
“Then the batch should not be used to demonstrate stability.” Zhao said the gauge reading was unreliable and that the pressure could be judged by the sound of the vessel.
Yan pointed at the seam. “The scorch is spreading.”
Lu moved closer, then stopped before reaching the furnace. The metal ticked softly. He looked to Zhao. “Can you shut the process down?”
“I can, but the batch will be lost.”
“Can it be cooled without opening the casing?”
The assistant said the valve needed a wrench from the far side of the hall. Yan glanced at the narrow passage. The disposal cart was blocking part of the route. If the pressure climbed further, workers would have to leave through the same aisle.
Lu ordered the nearest workers to move away from the furnace. The crowd began to shift, but there was not yet a clear route through the main doors. Yan moved the empty jars farther from the cart and turned it to open a path.
Zhao said, “The process is stable. We can finish the yield before servicing the gauge.”
Lu replied, “We will not risk the inspection crowd to preserve one batch.”
The warning had changed the crowd’s position. Clerks stepped back from the demonstration table. The assistants stopped tapping the needle. The pressure gauge kept climbing, and the scorch line continued along the vessel seam.
The apprentices at the stair began to descend. One clerk asked whether the batch could be paused without losing the whole yield. Zhao said a pause could damage the medicine. Steward Lu asked whether a damaged batch was worse than a damaged furnace.
Yan kept moving the jars away from the hall entrance. His healed arm still felt stiff when he reached above shoulder height, so he used his left hand and left the heavy cart where it was. He saw the side arch beyond the service passage and counted the people between the table and the exit. If they all moved at once, the narrow main doors would jam.
Yan looked at the side passage and the wrench station across the hall. The main doors remained partly blocked by a jar cart. The furnace was still running. No one had been hurt yet, but the hall needed a clear exit before anyone tried to reach the valve.
Steward Lu asked the assistant to prepare the shutdown wrench. The assistant ran toward the passage. The needle ticked again, faster than before. Yan put his left hand on the cart handle, ready to clear the route if the crowd surged.