"Lady Xu, there must be something in these leaves!"
"It is not a vapor, not a scent, nor is it a common medicinal property."
"It has no weight, cannot be measured by a scale, and cannot be accurately tasted by the tongue."
"But if a person lacks it, their gums bleed, they are blind at night, their legs grow weak, and their wounds struggle to heal."
"If we can isolate it, our marching armies will never again have to rely on the heavens for their vegetables."
"We can create medicinal rations, life-saving pills, things that will sustain the lives of the hundred thousand soldiers at the northern border!"
Li Sheng felt his scalp tingle as he listened, unable to resist interrupting.
"Valley Master Su, could you take a breath first? Your words sound highly valuable, but also quite terrifying. What kind of thing has no weight yet claims lives? Don't go dragging ghosts into the study in the middle of the night."
Su Mu ignored him completely, his eyes fixed solely on Xu Qinghuan.
Xu Qinghuan sat behind the desk. On one side of her hand lay the military ration spoilage inventory sent from the capital region, and on the other were Su Mu's papers, covered in notes from his pickled cabbage experiments.
One was a blade of the imperial court, the other a spark of the workshop.
The two items were placed on the same desk, yet both pointed directly to the life and death of the northern border.
Xu Qinghuan did not praise Su Mu, nor did she follow his train of thought. She merely raised her hand, picked up the cabbage leaf, used a bamboo skewer to peel back the stem, and placed it back onto the dish.
"Su Mu, with these words of yours, you have already gone further than ninety percent of the imperial physicians in the Great Qian Dynasty."
Su Mu was just about to speak when Xu Qinghuan continued.
"But this is also as far as it goes."
Su Mu's voice caught in his throat.
Li Sheng grimaced to the side, thinking to himself that it was over.
Valley Master Su had just praised himself to the heavens, and the young miss had backhandedly pulled the ladder out from under him.
Xu Qinghuan looked at Su Mu.
"You taste with your tongue, weigh with your hands, bake with fire, and soak in water. You can see a few steps further than ordinary people."
"But your eyes still only see the leaves, the scale only measures weight, and medical texts will only write the results as qi, blood, and vital energies."
"You say there are microscopic substances in the leaf. That statement is not wrong."
"The mistake lies in your attempt to find them with your current pair of eyes."
Su Mu's throat went dry. It took him a long while to squeeze out a sentence.
"Does Lady Xu mean that it cannot be seen by the human eye?"
"The human eye can see copper coins, the edge of a blade, leaf veins, and insect eggs, but it cannot see the even smaller living creatures in the water."
"Much less can it see the microscopic dust swimming in the blood, nor the tiny essence of life that stops gums from bleeding."
Xu Qinghuan pointed to the water cup on the table.
"This cup of water is colorless to the taste and crystal clear under the lamp. Do you dare say there is nothing inside it?"
Li Sheng looked at the water cup, then looked at Xu Qinghuan, and silently put back the tea he had just picked up.
Su Mu leaned forward, his sleeve knocking over a copper weight. The copper weight rolled to the edge of the desk and was stopped by Xu Zhan's hand.
"There are living creatures in the water?"
"Drinking some water causes diarrhea, while drinking other water does nothing."
"If wounds in the army are washed with muddy water, they will fester, rot the flesh, and kill people."
"Some call it evil qi, or foul poison, or unacclimatization. These terms can record the symptoms, but they cannot grasp the root cause."
"The root lies in a much smaller place."
Su Mu's breathing grew erratic. He stared at that cup of water as if staring at an unopened treasure trove.
"A much smaller place..."
Xu Qinghuan took a piece of paper and wrote a phrase on it.
Microscopic world.
Su Mu looked at those words, his fingers hovering in mid-air, not daring to touch them.
Xu Zhan also leaned in for a look and frowned, saying, "So small it can't be seen, yet it can harm or save people. If someone truly figures this thing out, the medical clinics will have to change their ancestral tablets."
Li Sheng couldn't help but add, "Then the army camp cooks will have to change too. Whoever pours dirty water into the pot will probably be charged with poisoning."
Xu Qinghuan gave a sound of agreement.
"Therefore, Su Mu, dehydrated vegetables are not the end; they are merely a sliver of light leaking through the crack in the door."
"If you truly want to walk inside, you must first build an eye."
Su Mu snapped his head up.
"Build an eye?"
Xu Qinghuan spread out a new sheet of paper, dipped her brush in ink, hovered her wrist for a moment, and then began to draw on the paper.
She drew very quickly.
The lines were not particularly refined. First was a rectangular wooden stand, then a circle drawn in the center, with a wooden frame added around the edge of the circle.
Below it, she added a base that could slide up and down, then sketched out two support rods to the side, and at the top, she drew a small hole and a circular piece.
The more Li Sheng watched from the side, the more confused he became.
To call this thing a lamp stand, it didn't quite look like one.
To call it a crossbow mechanism? It had no string. To call it a medicine furnace? It didn't even have a belly.
Su Mu, however, looked closer and closer, his nose nearly touching the paper.
Xu Zhan remained silent for a moment before offering a serious evaluation.
"Little sister, this drawing of yours... is quite lethal."
Li Sheng nodded.
"This subordinate can see it too. Whoever tries to build based on this is in for bad luck."
Xu Qinghuan raised her eyes and swept a glance over them.
The two men shut their mouths.
She tapped on the circular mirror in the drawing.
"Here, you inlay crystal or colored glaze, ground into a circular lens that is thick in the middle and thin on the edges."
She then tapped the base below.
"Here, you place water drops, blood drops, or vegetable juice, spread thin enough to let light through. The base must be able to be pushed and raised or lowered."
She then tapped the small hole at the top.
"Light enters from here, passes through the circular lens, then through the sample, and a person looks from above."
The lamplight reflected in Su Mu's pupils. Unable to stand still, he gripped the edge of the desk directly.
"Grinding crystal round can magnify small objects?"
"Yes."
"How large can they be magnified?"
"That depends on how well you grind them, how the two lenses are paired, and how the light travels."
Xu Qinghuan set down her brush.
"If it succeeds, tiny insects in the water and foreign matter in the blood."
"Even mold spots, fungal threads, and medicinal juice residues will all reveal their forms."
Su Mu trembled all over as he listened.
"So one can actually look at things this way..."
He suddenly grabbed the piece of paper, but fearing the ink wasn't dry, quickly let go.
"Lady Xu, what is this object called?"
Xu Qinghuan did not give a overly mystical name.
"A microscope."
Su Mu muttered the word over and over, his voice growing lower and lower until, at the very end, only a burning passion remained in his tone.
"Microscope... revealing the microscopic..."
"If this object is completed, the ways of medicine, pharmacology, agriculture, brewing, and so on! All of them will have to adopt a completely new perspective."
"Why wine turns sour, why wounds fester, why plagues spread through camps, why water in saline-alkali land rots roots—perhaps the clues to all of these can be found in that microscopic world!"
Xu Qinghuan didn't pour cold water on his enthusiasm; she merely pushed a blank token from the edge of the desk over to him.
"You cannot build it."
Su Mu froze.
These words were even more ruthless than her earlier remark, "this is as far as it goes."
Li Sheng almost laughed out loud, hurriedly using his sleeve to cover half his face.
Su Mu stood stiffly before the desk, completely unable to muster a retort.
Xu Qinghuan added a sentence.
"Sunset Valley knows how to draw blueprints, design mechanisms, and make crossbows."
"But the first hurdle for this object does not lie in the mechanisms."
"It lies in the lenses."
She tapped the circular lens in the sketch.
"The colored glaze must be pure, without sand holes or air bubbles. Moreover, the ground surface must be smooth, and the thickness must be precise. If it is off by even a fraction, all you will see are phantom images."
"Take the blueprint and go find Jenny Huang."
"Between the two of you, one understands the microscopic, and the other understands craftsmanship."
"Whether you argue or fight, bring me a usable prototype within three days."
Su Mu tucked the blueprint and the note into his robes, keeping them closer and more secure than banknotes.
"Three days?"
Xu Zhan spoke up from the side, "You think that's too long?"
Su Mu shook his head, turned around, and dashed outward.
"I think it's too short, but short or not, it must be done. If I don't get the furnace lit before dawn, my stealing half a bag of cabbage tonight will have been for nothing!"
Li Sheng chased him to the door and shouted.
"Valley Master Su, use the door!"
"The window is closer!"
Su Mu dropped those words as he vaulted out of the study window. A clattering sound echoed from the courtyard as he kicked over a wooden bucket.
Xu Zhan looked at Xu Qinghuan.
"Putting him and Jenny Huang together, I'm afraid the blacksmith shop is going to suffer a disaster tonight."
Xu Qinghuan gathered the vegetable leaves on the table.
"A disaster is still better than a standstill."
Inside the blacksmith shop, Jenny Huang was crouching by the furnace, taking inventory of the inverted-tooth concealed clasp nets that had caught three arsonists last night.
She hadn't quite come down from her high of smugness yet, bragging to everyone she met about how the three-layer inverted teeth could trap a leg, talking so much that the blacksmith apprentices' ears were growing calluses.
The furnace fire glowed a bright red. The sound of hammering had just ceased when a man with disheveled hair rushed in through the door.
Jenny Huang almost threw the iron tongs right out of her hand.
"Su Mu, are you pretending to be a ghost in the middle of the night?"
Su Mu slapped Xu Qinghuan's note down in front of her and unrolled a blueprint.
"Official Xu's orders. I'm here to borrow your furnace and your people."
She bent over and studied it for a long time, then held the blueprint up to the light of the furnace.
"What the hell is this?"
"A microscope."
"What is it used for?"
"To look at the microscopic world."
"Speak plainly."
Su Mu pointed at the central circular mirror.
"To magnify tiny, invisible things in the water."
Jenny Huang stared at the circles, then at the base Xu Qinghuan had casually sketched out. After a long moment, she raised a hand to rub her temples.
"Looking at Official Xu's drawing, even the founding masters of our trade would be forced to change professions."
Su Mu grew anxious.
"Never mind the drawing, just tell me if it can be built!"
Jenny Huang pressed the blueprint onto the anvil and used a charcoal pencil to trace over the outer circle of the lens.
As soon as the precision of a master craftsman flowed from her hands, the apprentices in the room immediately shut their mouths.
"The wooden frame isn't hard, the base isn't hard, and the lifting mechanism isn't hard either. The screw can be made too. As for the fine teeth, they'll just have to be filed down slowly."
She tapped the position of the lens with her charcoal pencil.
"The difficult part is here."
Su Mu leaned in closer.
"Crystal?"
"Whether it's crystal or colored glaze, if there is even the slightest bit of sand trapped inside, the light will scatter as soon as it enters."
As Jenny Huang spoke, she picked up a scrap piece of transparent glaze from the material basket and turned it against the furnace light. It was densely packed with tiny bubbles, nothing but trouble.
"You need it thick in the middle and thin on the edges. Both sides must be smooth, and it has to be perfectly round without any deviation. Grind a fraction too much and it's ruined; grind a fraction too little and the vision will be blurred."
Su Mu immediately suggested, "Grind it with fine sand, then polish it with sheepskin."
Jenny Huang scoffed.
"Do you think you're sharpening a kitchen knife? Even fine sand has coarse grains. One press and it leaves a scratch. Sheepskin can polish it bright, but it can't polish it flat."
Su Mu was unconvinced.
"Sunset Valley has a water-powered grinding wheel. Its rotation speed is very steady."
"Steady my foot. If the wheel axle tilts even a little, the lens surface tilts with it."
"Then make a three-point support fixture!"
"Three points can clamp the outer ring, but they can't secure something thick in the middle and thin on the edges. If the pressure shifts even slightly, snap, it will shatter right before your eyes."
Su Mu gestured with his hands.
"Use wax as a base, soften it over a gentle fire, and stick the lens blank onto the wax to grind it."
Jenny Huang's eyes lit up for a moment, but then she shook her head.
"Wax shifts when heated. The lens surface won't be flat."
"Switch to pine resin putty."
"The particles in the putty are too coarse."
"Mix clam shell powder with glue."
"Clam shell powder gets slippery when it meets water; the grinding wheel won't be able to grip it."
The two of them went back and forth, firing off ideas as sparks shot up from the mouth of the furnace.
The apprentices stood in a row hugging their hammers, their heads spinning as they listened, but no one dared to interject a single word.
Suddenly, Jenny Huang tossed the scrap piece of glaze into a water basin. With a sizzle, a cloud of white steam rose up.
"Su Mu, what you want isn't just to forge a tool. You want to train light like a dog, making it go exactly where you tell it to."
Su Mu snatched the wet glaze out of the water, baring his teeth as the heat scalded his hand.
"Then let's train it!"
Jenny Huang stared at him. After a long moment, she slammed her iron tongs against the anvil.
"Fine."
She raised a hand and pointed at three apprentices.
"Go, sift the finest river sand three times. If it isn't sifted clean, don't even think about sleeping tonight."
"Then bring out all the transparent glaze from the storehouse. Toss aside any pieces with bubbles. And those thin brass sheets, cut them into circles."
Su Mu didn't stay idle either. He grabbed a charcoal pencil and started drawing lines on the wall.
Just as he was drawing the third line, Jenny Huang snatched the charcoal pencil away from him.
"The light path you're drawing is even more crooked than Miss Xu's blueprint."
"Do you understand light?"
"I understand when something is crooked."
