A quarter hour later, two bailiffs brought the items in and laid them out in the hall.
The three officials glanced at the materials and then turned to Xu Qian.
Prefect Chen said grimly, "Everything you asked for is here. You had best give this official a satisfactory answer."
His attitude had shifted. In that quarter hour, this fourth-rank official had racked his brain and been forced to admit: Xu Qian's reasoning held weight. But many threads of doubt remained unresolved — for one, the tax silver plunging into the river had been witnessed as fact. What hidden mechanism lay behind it, he could not fathom.
Xu Qian nodded and crouched before the implements: candles, salt, a porcelain cup, and iron wire.
The task was simple. High school chemistry: extracting sodium metal.
In ancient times this should have been impossible — two obstacles: electricity, and the melting point of sodium chloride. But in this world, Xu Qian knew of one profession that could overcome both.
The Directorate of Celestials' Artificers, Rank Six: Alchemist.
Alchemists in Great Feng were a household name. Their inventions and creations had long since woven into the daily lives of ordinary people.
Xu Qian wasn't certain that the exploding silver was actually sodium metal — that didn't matter. What mattered was opening a new line of thought to explain the phenomenon of tax silver that exploded.
In case-cracking, bold hypotheses and rigorous deduction came first. Verification and evidence-gathering came after.
He dissolved the coarse salt in water, stirred, covered the cup's mouth with raw paper, and slowly poured the saline through. After filtering, he set the porcelain cup over a candle flame, stirring constantly with a bamboo splinter.
Before long, the water in the cup evaporated, leaving behind crystals — sodium chloride. The essence was simply further purifying the salt.
Prefect Chen, the middle-aged man, and the stunning yellow-dressed girl stood at the edge watching, wholly absorbed.
Xu Qian looked up and gave the girl a wide grin. "My lady must be a disciple of the Directorate of Celestials."
He'd spotted the geomantic compass at her waist. That tool — no one outside the Directorate touched it.
She gave a soft hum and smiled. "My teacher is the Director himself."
Her refined, radiant oval face was like a peeled egg — pale, flawless, without blemish.
The Director's disciple... well, that makes her chest situation entirely irrelevant. Xu Qian softened his voice. "Would my lady help me melt these crystals?"
Sodium chloride's melting point was roughly eight hundred degrees.
The yellow-dressed girl pursed her lips. "Fire control is the Alchemist's ability. I'm only a Feng Shui Master."
"But my teacher gave me an artifact." She changed tack, lifting the geomantic compass from her waist. Her jade-like fingers tapped a few times, channeling qi into it, and the character for 'Fire' lit up.
"Stand back!"
Xu Qian leapt backward. An instant later, a tongue of blindingly bright flame erupted, engulfing the porcelain cup.
"Stop!" Xu Qian called out immediately, then swiftly inserted the two iron wires into the cup. "Now lightning... no — Thunder Arts! Be careful with the voltage. This step is difficult, and it may take many attempts."
She spun the compass, her delicate finger lighting up the 'Thunder' character. A few arcs of electricity flashed through the air and struck the iron wires.
*Crackle...* The molten sodium chloride underwent a violent chemical reaction.
"Stop!"
Xu Qian held his breath and peered into the cup. A silvery lump of metal had formed at the bottom, with unconverted crystals and impurities at the edges.
It had worked on the first try. The voltage had been just right. Xu Qian was delighted. Electrolysis to produce sodium metal required roughly six to fifteen volts — he'd steeled himself for repeated failures. But fortune had smiled on him, and he'd hit it in one.
Prefect Chen and the middle-aged man crowded over to look. Inside the cup lay a lump of silver-colored metal. At first glance it bore a startling resemblance to true silver.
Prefect Chen's pupils contracted. He was deeply shaken.
Li Yuchun clenched his fists, staring blankly at the silver lump as if lightning had split the sky and parted every fogbank in his mind.
"My lords, observe." Xu Qian tipped out the sodium metal, wrapped it in paper, and weighed it in his hand. "This substance is far, far lighter than silver, yet in appearance it's nearly identical. If someone used this to impersonate silver, could they pass it off as genuine? Please, weigh it yourselves."
He handed the sodium to Prefect Chen. By now the metal's color had dulled, making it virtually indistinguishable from silver.
The middle-aged man took it, weighed it, his eyes gleaming. "Indeed much lighter. If the shipment had been this substance, everything would make perfect sense. Miss Caiwei, try it."
The yellow-dressed girl took it, hefted it, then fixed Xu Qian with an odd look. "Are you... an Alchemist?"
No, I am not. I am merely a courier of chemistry.
Being a scholar, Prefect Chen's mind moved faster. His delight faded, and he shook his head. "No, this still doesn't work. Even if the silver was swapped for this substance, what of the explosion? If no demon lurked in the river, why would the false silver explode upon entering the water?"
Xu Qian offered no reply. He took the sodium, walked to the desk, and dropped it into the brush-washing cistern.
A fierce blaze flared. Thick smoke billowed.
*Boom!*
The sodium reacted violently in the water, cracking the cistern with a web of fine fractures.
"This... this..." Prefect Chen was dumbstruck.
"This false silver explodes on contact with water. That explains why such a violent eruption occurred when the silver fell into the river," Xu Qian explained.
The middle-aged man murmured, "From the very beginning, we were misled. The culprit used the explosion and the demon wind to make us think a demon was at work. They steered our investigation toward tracking and hunting."
"No wonder the Astrology Bureau's Qi Observation Arts detected nothing."
Xu Qian added, "After the silver sank, the soldiers recovered only a little over one thousand taels. If I'm not mistaken, that silver was laid on the topmost layer as a blind."
Every gap sealed. Every anomaly accounted for.
"Xu Qian!" The middle-aged man's eyes brimmed with praise. "Well done. Very well done."
Then his brow furrowed, his gaze pausing at Xu Qian's crooked collar. Li Yuchun took the opportunity of a shoulder pat to straighten it for him.
Xu Qian was overwhelmed by the gesture. This official truly thought so highly of him.
Prefect Chen frowned. "If the silver was fake, then where is the real silver?"
The yellow-dressed girl's expression turned grave as well. "The tax silver left the treasury and entered the capital, passing through many hands. If we are to assign blame, a great many officials would face prison. Recovering the silver would be no easier than dredging the ocean for a needle. And this matter has already exceeded our authority — we must report it to His Majesty."
Prefect Chen nodded. That was exactly what he meant.
The middle-aged man held a different view. In a low voice he said, "The silver was escorted all the way to the capital, changing hands many times. If it had been counterfeit all along, it would have been discovered long ago. The only possibility is that it was swapped very recently."
Prefect Chen's eyes lit up. This drastically narrowed the scope of investigation.
"Guards! Prepare the sedan — quickly, this official must depart at once." Prefect Chen rushed out of the inner hall.
The middle-aged man followed close behind.
Xu Qian called after them urgently, "Lord Prefect! Do not forget your promise to this commoner."