Chapter 65: Water Levigation

The herb wholesalers knew all the town’s medicine shops, which bought their stock here. Guizhi Hall purchased little, but it was still a customer. Poor business now did not mean poor business for ever, and goodwill brought trade. As Shaoyang arrived, the dealers rose to greet him.

A plump merchant at the first stall was particularly warm.

“Young Master Zuo! What medicines are you buying today?”

“My friend gathered some herbs in the mountains. Do you buy them?”

“Of course! How could we sell medicine without buying it? Most of what you see here was gathered in the mountains and sold to us. We take large lots and small!”

Shaoyang brightened.

“Your medicines are all gathered in the mountains?”

“More or less.”

“No one grows them to sell?”

“Why would anyone grow them? The mountains are full of them.”

Excitement stirred in Shaoyang. So most early Tang medicinal materials were gathered wild. Few people cultivated them.

Growing them on a large scale would certainly save time and labour compared with gathering, produce higher yields and allow bulk production. Better still, he could select crops to meet market demand—something wild gathering could not achieve.

“Where are the herbs?” the merchant asked. “Let me see.”

Putting his thoughts aside, Shaoyang took Peilan’s basket, set it beside the stall and laid out its contents.

“Here.”

The dealer crouched and sorted through them.

“Good enough quality.”

He calculated on his fingers.

“Since Young Master Zuo brought you, I won’t haggle. Twelve wen for the lot. How’s that?”

Peilan was overjoyed. A morning’s gathering had brought twelve wen—more than she might earn selling wood for several days.

Shaoyang thought the price fair and nodded.

“Agreed. Pay her.”

The merchant counted twelve coins into her hand.

“Bring your herbs straight to my stall in future, miss. I guarantee the highest price in the whole market.”

She nodded happily, accepted the money, then glanced at Shaoyang. Counting out six wen, she offered them to him.

“What are those for?”

“You gathered them with me. Half is yours.”

He laughed.

“You call me Brother Zuo, yet insist on being so distant? If I wanted these few coins, I wouldn’t have taught you. Keep them.”

He pushed the money back.

She caught his hand and pressed the six coins into it.

“I’m going.”

He knew her stubbornness. Once she decided something, she would not change it. Since she believed the herbs jointly gathered, she would insist on sharing.

But he did not give in easily either. Stepping in front of her, he caught her hand and pressed four coins back into it.

“If you insist on reckoning precisely, let’s be precise. I can only take two.”

“Why?”

“Only the first gastrodia was dug by me. You dug everything else.”

“But you showed me. Without you, I wouldn’t have known them.”

He deliberately put on a stern face.

“I don’t care. Whoever dug it gets paid. You’re stubborn? So am I. Like you, I don’t want what isn’t mine. Take these four, or I’ll throw them away!”

She smiled gratefully and put them inside her robe.

“Thank you, Brother Zuo.”

“That’s better.”

He smiled.

“Wait a moment longer. I’ll buy and prepare the medicine for Erzi’s eyes, and you can take it back. He needs treatment soon; we can’t leave it too long.”

She agreed and stood watching.

Shaoyang surveyed the stall, pinched a little powder from a sack and rubbed it between his fingers. He frowned.

“Why is your borax so coarse?”

“Young Master Zuo, borax is stone,” the merchant said with an accommodating smile. “Getting it this fine is already quite good. Look at the other stalls if you don’t believe me. Mine is the finest ground. Find anything finer and I’ll buy as much as you have!”

A thought stirred in Shaoyang.

“You mean that?”

“Fatty Dong’s word is his bond.”

“What would you pay?”

“Do you really have some?”

The boast had been mere salesmanship. Seeing Shaoyang’s interest, Fatty Dong became cautious.

“I’d have to see it. But I honestly don’t believe anyone can grind borax finer than mine.”

Shaoyang checked the amethyst, native copper, magnetite and other mineral medicines. Their particles were coarser still and plainly harder to pulverise.

“I can make these finer than yours too. As fine as white flour.”

“Surely not! You do like a joke.”

Ignoring that, Shaoyang walked from stall to stall with his hands behind him. Many dealers had heard their exchange and could not resist boasting about their own borax. None was necessarily worse than Fatty Dong’s, but all were much the same as Guizhi Hall’s: grains the size of millet.

He returned with an idea firmly in mind.

“I’ll process some at home and bring it for you to see. It will be much finer than anything on your stalls.”

“If you really have that, I’ll certainly buy it!”

Shaoyang nodded and left the market with Peilan.

“None of these medicines is fine enough. I must process them myself. Go home first. Father says we’ll visit your village again the day after tomorrow to examine the young master and Auntie Li. Probably not tomorrow. But I’m afraid waiting that long could affect Erzi’s eyes.

“If you gather herbs tomorrow and bring them down to sell, stop at Guizhi Hall. I’ll give you the medicine.”

She thanked him, shouldered her basket and left.

At home, Madam Liang and Huixiang were preparing supper in the kitchen. Hou Pu and Zuo Gui were talking in the main room, the shop door half open. Dadou and Douhua played on the threshold. Seeing their uncle, they clamoured for the squirrel again.

He had no time for that. After asking how long until supper and learning there was still a while, he addressed his father.

“I’m going to process some medicinal material. We may be able to sell it.”

“What?” Zuo Gui had not followed. “Process what?”

“The borax at the market is coarse. I know how to turn it into a very fine powder, and other mineral medicines too. Fatty Dong says he’ll buy it. We could earn a processing fee.”

His father plainly did not believe him.

“And how would you know how to do that?”

“The travelling physician I told you about taught me.”

“What travelling physician?” Hou Pu asked curiously.

“Zhong says he gave some food to an old travelling physician who was nearly starving,” Zuo Gui explained. “The man showed him a medical book with some prescriptions.”

Hou Pu laughed and turned to Shaoyang.

“He was tricking you into feeding him! If he really had such skills, why didn’t he use them to earn money? Why end up begging?”

“Exactly,” Huixiang laughed. “Brother’s too trusting.”

Shaoyang ignored them and went straight into the preparation room.

Zuo Gui had intended to stop him, but with his son-in-law present he hesitated. A son-in-law was considered an outsider, and he disliked scolding his child before outsiders, even one so close.

Shaoyang shut and bolted the door and began processing borax.

Before the Tang, hard mineral medicines were generally heated directly in a fire, then pounded, leaving rather coarse particles. Song techniques greatly improved their pulverisation, especially for minerals such as amethyst. Heating to redness and quenching in vinegar exploited expansion and contraction; grinding followed by water levigation then produced far finer powders than earlier methods.

Water levigation was a traditional processing technique. Broken material was placed in a mortar with water and ground into a paste. More water was added and stirred in. The coarse particles sank, and the suspended liquid was poured off immediately. The settled material was ground again and the process repeated.

Different suspension behaviour separated coarse from fine. Repeated grinding transformed water-insoluble minerals into very fine powder. Impurities that would not suspend were discarded. The suspensions were combined and left to stand; the sediment was collected, dried at low temperature and ground once more.

The resulting powder was exceptionally fine, suited to preparations such as eye medicines that demanded it.

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