Chapter 72

Zhuo Siheng's authority grew several times over in ten days, so that when he walked into the six-offices yamen to find Pan Guangling and talk over the crag-kiln business, every clerk rushed out in fright to greet him.

Looking at the rows of officials high and low drawn up on either side before the yamen, not daring to breathe loud, Zhuo Siheng hardly knew whether to laugh or cry. But on the surface he was all warmth, greeting each man kindly and asking after the old backlog of neglected work they were making up. He said Lord He had written yesterday that Yongming Commandery's hills and waters were a wonder past anything in the mortal world, and that he meant to linger a good while longer, and had asked Zhuo Siheng to take still more pains over the commandery's government for him.

The crowd heard him out with held breath and ashen faces. Their days in Zhuo Siheng's hands stretched on without end, and each man understood without a word: this second-in-command had not only the nerve and the hand to master his underlings, but a gift for boxing out his superior too.

They traded a glance, and found every heart and every eye seemed to roar the same thing. You call this the hand and the ability of a newly-made official of twenty-four?

The six-offices yamen was not large, and the courtyard furthest in was the works office, with the fewest people and the most out-of-the-way rooms. But perhaps because it was the works, its clerks were handy men. The doors and windows, old and long unmended, had all been patched, and looked old but good for another eight or ten years, with more of a thriving air than the rest. Zhuo Siheng knew this was thanks to the head of the works office, Pan Guangling, who was in the inner hall just now studying how to brighten the crag kiln's glaze. The moment Zhuo Siheng stepped in he caught the heavy smell of a chemistry laboratory, and at first glance half thought he'd walked into some Daoist convent's alchemy room. There were stoves and firing-tools of every kind, powders and liquids he couldn't name, and on the floor, in heaped basins and baskets, nothing but broken stone or ore, and a few plants he couldn't put a name to either.

"Lord Zhuo! Come and look at this!" The moment Pan Guangling threw himself into his work, the whole man lit up with a wholly different spirit, waving his arms, charming even at his most frantic. Zhuo Siheng came over to look and found him working at a small crock of dark-grey slip.

"Is this the glaze?" Zhuo Siheng had been to the works, so he could tell.

Pan Guangling nodded, excited. "Wu Xing told me they could never work out how to make the glaze-color paler and finer. I thought it might be because our local kaolin holds too much damp and is loose and full of holes, so the surface of the fired body isn't smooth enough. I thought I'd try the other way, make the glaze rougher to fill the gaps, so I tried adding more glaze-stuff and plant ash. At first it wouldn't blend, and there were always blotches when it was laid on. But then, with your hint, I fired in some hemp-ash drawn from sisal, and look, now the glaze runs smooth!"

Zhuo Siheng couldn't help clapping him on the shoulder with a few words of hearty praise, and sat down to look himself. On the table were a number of the crag kiln's improved pieces. In truth they were much better than what Zhuo Siheng had seen in the capital, at least far less coarse. But the clay-yellow of that slip was truly too glaring. If the color couldn't be solved, the crag kiln's growth would surely be held back by it.

He said what he thought, and Pan Guangling sighed. "Wu Xing and I have talked of this too. I'm a reading-and-official family's son, after all, and I've seen plenty of the porcelain in the studies and kitchens of my elders and kin. I told Wu Xing that any house with the least face sets most store by a porcelain's color and its elegance. In a study it's mostly white, green, and blue, and if there's red it's a pale bean-red. This mud color would never get through the door of anyone who'd truly pay for such things."

"Didn't Wu Xing tell us as much himself?" Zhuo Siheng recalled. "He said the clay they dig here to make the glaze gives only this color, no match for other places, and it can't be changed. A kiln must take its material from the ground it stands on. To haul clay from far off would spoil its natural temper and likely leave it useless, and cost too much besides. A piece fired from it would have to sell dear not to lose money, and if it sold dear, who'd pay a high price for our ware?"

"That's the way of it." The excitement of a moment ago fading, Pan Guangling knit his brows. "Wu the kiln-master has tried near everything, and all we could help with we've helped with already."

Zhuo Siheng pulled a chair over and sat beside Pan Guangling. "Xiao Pan, do you know why the clay here, ground to powder and fired, comes out a yellow glaze?"

Pan Guangling shook his head. "Wu Xing said it's the color he learned from his elders as a boy."

"You've seen the hill by the works where they dig the glaze-clay. Do you remember its color?"

"Red. A deepish red. Darker than cinnabar, but not a flushed red either."

"Right. Because that earth holds iron."

"Iron?" Pan Guangling scratched his head. "But we've no iron mines here..."

Zhuo Siheng had no way to explain to him that the red earth held a great deal of free iron oxide, laid down and weathered over the long ages of the earth's crust, nor that this free iron oxide, fired in the kiln above a thousand degrees, turned yellow because the iron changed through the reaction into ferric ions, and so gave that peculiar color.

He could only explain with the part that lay outside his high-school chemistry. "On the road to Jinzhou I called at the iron-smelting works and the government foundries along the way, and they told me the ore often holds quartz and feldspar, and in the smelting these come out with the look of glass or porcelain glaze. I think it's for this that other kilns' glazes have a glassy, clear, fine quality, and ours doesn't."

"Then what's to be done?" Hearing it, Pan Guangling felt there was no play left to put on.

But Zhuo Siheng smiled with certainty, and drew slowly from the rattan case at his side a little cup of pale blue-green, as if misted with rain. "The experienced foundrymen told me too that they'd now and then seen that kingfisher-green and pale azure of fine porcelain. It happens when the iron sent from the mine isn't pure enough, with a lot of waste slag. But mix that impure ore into a lime glaze or a plant-ash glaze, and it makes a lovely color like this shadow-blue. That's the good of an official kiln taking its material from its own ground. This celadon from the Mi kiln in Qingzhou is just such a case, and that's where its fine glaze comes from. I daresay there are a good many brush-washers and trays from this kiln in your father's study, Xiao Pan?"

Pan Guangling nodded again and again.

Zhuo Siheng next brought out a milk-blue warming-pot, narrow of mouth and broad of body. "The foundrymen said too that if the iron ore sent them had phosphate ore mixed in, the firing might throw up blue crystals. The An kiln in Yuezhou takes its color so. Only, the phosphate that comes with the iron ore is very uneven, so each time the An kiln opens is like a throw of the dice. No one knows which blue this batch will be, or how deep. But just for that, a truly lovely blue glaze, light or deep, can't be had for the asking, and that is why the An kiln's ware is so precious."

Last, he felt out a clean, clear little white porcelain dish. "The Dang kiln in Muzhou is the most marvelous of all. Its glaze has that purest white, likely because the local soil holds almost no iron, only quartz and mica ground and pounded, with agate powder added, and only then can it fire out that crystal clarity found nowhere else under heaven. That the Dang kiln has stayed an official kiln for centuries, through reign after reign, is not without reason."

"But these are all gifts nature gave them. How is our crag kiln to match them?" Pan Guangling felt dimly that Lord Zhuo's confidence was not without ground, yet he truly found it hard to believe the thing could really be solved.

"The truth is, except for the An kiln, which chases the thrill of the kiln-opening, every other works more or less meddles with how much ore is in the glaze to tune the color. I asked Wu Xing too, and he said they'd once tried mixing in some lime powder, but that only made the glaze darker." Zhuo Siheng paused and smiled. "You've the crag-kiln glaze-powder you brought back here, Xiao Pan, haven't you? Let's try something."

Pan Guangling hurried to scoop a bowl of glaze-powder, not yet mixed into slip, from a cloth bag at his side. This was the fine powder got from the red earth-and-rock of the hills by the works, ground, then washed and sieved and settled. For his own trials he hadn't yet mixed in plant ash. Zhuo Siheng took out a little clay bottle and pulled the stopper, and the room filled at once with a strong, sharp, nose-wrinkling sour smell.

"Is this our local country vinegar?" Pan Guangling rubbed the tip of his nose. "Only the farmhouse kind, fresh and un-watered, has this reek. Is your taste so heavy, my lord?"

He dimly remembered Zhuo Siheng was a northerner. He himself was southern born and bred, and had only heard that northerners liked their food sour and salty, but hadn't known one could stomach vinegar as strong as this.

"How could I drink it? The vinegar bought for the house is watered well before it's used. This I got from a farmer, newly made, not two days old, at its strongest, for us to try." With that Zhuo Siheng poured the vinegar into the bowl of brown-earth glaze-powder.

"And... and then?" Pan Guangling's head ached from the vinegar-reek, but he saw the powder take it far better than he did.

Again Zhuo Siheng could not explain that acetic acid neutralizing the iron would make iron acetate, and that the iron in iron acetate was true ferric iron, giving a pale-yellow solution, a pale yellow far lovelier than the sand-yellow of the fired slip. If this chemistry worked, they could try to lower by chemical means the iron that made the crag kiln's awkward glaze-color, and so get a paler, plainer color with fewer impurities. Add Pan Guangling's own method, and if it worked, the glaze would be finer and more even too. The result should be far from bad.

But vinegar was not acetic acid. It held many impurities, perhaps lactic acid formed from natural matter too, and these were things in the trial he couldn't control. So Zhuo Siheng wasn't a hundred parts sure it would work, or whether he'd need to adjust the vinegar's purity and makeup. All that would take slow trying, time after time.

Still, he had confidence.

His years as a science student hadn't been for nothing. If his chemistry teacher knew this prize pupil could put his learning to such living use, he'd likely have liked him the better for it.

As he thought, Zhuo Siheng saw Pan Guangling take out paper and brush to set it down, then mix up a bowl of glaze-powder with plant ash in it, and add vinegar to that too in the same measure, to see how the result differed.

A control experiment? Zhuo Siheng was struck with admiration, and thought: this Pan Guangling, were he where I come from, would make a fine science man. Only, a pity...

In the middle of that pity a thought rose in him, and it did not frighten him. Instead it opened his heart and his eyes wide, as if he'd seen at last the very thing he'd always hoped for.

"Xiao Pan, I want to ask you something." He fought down the excitement and gladness in him and played the proper grown-up. With no firm shape to the thing yet, Zhuo Siheng did not mean to let slip the great design just born in him.

"Ask away, my lord. I'll tell you anything I know."

Zhuo Siheng weighed his words, and asked the thing in a way that looked mild, but to a man who lived here was a little against all the rules. "If the examinations could test these matters of numbers and crafts and tools, what would you make of it?"