When Hoong had placed it in front of the tea cupboard, the judge stepped up on the seat. Lifting the candle, he scrutinized the red-lacquered roof beam.

"Give me your knife and a sheet of paper!" he said excitedly. "And hold the candle for me."

Judge Dee spread the paper out on the palm of his left hand, and with his right scraped with the tip of the knife at the surface of the beam.

Stepping down, he carefully wiped the point of the knife clean on the paper. He gave the knife back to Hoong, the paper he folded up and put in his sleeve. Then he asked Hoong "Is Tang still in the chancery?"

"I think I saw him sitting at his desk when I came back, your honor," the sergeant replied.

The judge quickly left the library and walked over to the chancery. Two candles were burning on Tang's desk. He sat hunched in his chair, staring straight ahead of him. When he saw the two men enter he hurriedly got up.

Seeing his haggard face, judge Dee said, not unkindly, "The murder of your assistant must have been a great shock to you, Tang. You better go back home and go to bed early. First, however, I want some information from you. Tell me, were there any repairs done in Magistrate Wang's library shortly before his death?"

Tang wrinkled his forehead. Then he replied, "No, your honor, not shortly before his death. But about two weeks earlier, Magistrate Wang told me that one of his visitors had remarked on a discolored spot on the ceiling, and promised to send along a lacquer worker to repair it. He ordered me to let that workman in when he would come to do his work."

"Who was that visitor?" Judge Dee asked tensely. Tang shook his head.

"I really don't know, your honor. The magistrate was very popular among the notables here. Most of them used to visit him in his library after the morning session, for a cup of tea and a chat. The magistrate would make tea for them himself. The abbot, the prior Hui-pen, the shipowners Yee and Koo, Dr. Tsao and-"

"I suppose that artisan can be traced," Judge Dee interrupted impatiently. "The lacquer tree doesn't grow in these parts; there can't be many lacquer workers here in this district."

"That's why the magistrate was grateful for his friend's offer," Tang said. "We hadn't known there was a 'lacquer worker available here."

"Go and ask the guards," the judge ordered. "They must at least have seen that artisan! Report to me in my private office."

When he was seated again behind his desk the judge said eagerly to Sergeant Hoong, "The dust dropping in my tea supplied me with the solution. When the murderer noticed that dark spot on the ceiling, caused by the hot steam of the tea water, he realized that the magistrate always left the copper tea stove on that same spot on the cupboard, and that fact suggested to him his diabolical plan! H^e had an accomplice act the part of a lacquer worker. Feigning to work on the discolored spot, he drilled a small hole in the roof beam, straight above the tea stove. He put one or more small wax pills inside the hole, and those pills contained the poison powder. That was all he needed to do! He knew that the magistrate when he was engrossed in his reading would often let the tea water go on boiling some time before he rose and poured it from the pan into the teapot. Sooner or later the hot steam would melt the wax, and the pills would drop down into the boiling water. They would dissolve immediately and become invisible. Simple and effective, Hoong! Just now I found that hole in the roof beam, in the center of the discolored spot. A small quantity of wax was still sticking to its rim. So that was how the murder was committed!"

Tang came in. He said, "Two of the guards did remember the artisan, your honor. The man came to the tribunal once about ten days before the magistrate's death, when his excellency was presiding over the afternoon session. He was a Korean from one of the ships in the harbor, and could speak only a few words of Chinese. Since I had instructed the guards that they could let him in, they brought him to the library. They stayed with him there to see that he didn't pinch something. They say that the man worked for a time on the roof beam, then he climbed down his ladder and muttered something about the damage being so bad that he would have to lacquer the entire ceiling anew. He left and was never seen again."

Judge Dee leaned back in his chair. "Another dead end!" he said disconsolately.

MA JOONG and Chiao Tai went back t the Nine Flowers Orchard in high spirits. When they were entering the restaurant the latter said contentedly, "Now we'll have a real good drinking bout!"

But when they walked over to the table of their friends, Kim Sang gave them an unhappy look. He pointed at Po Kai, who was lying with his head on the table. A row of empty wine jugs was standing in front of him.

"Mr. Po Kai drank too much in too great a hurry," Kim Sang said ruefully. "I tried to make him stop but he wouldn't listen, and now he is in a foul temper; there's nothing I can do with him. If you two will kindly look after him, I'd better be off. It's a pity because that Korean girl is waiting for us."

"What Korean girl?" Chiao Tai asked.

"Yü-soo, of the second boat," Kim Sang replied. "Today she has her night off, and she said she would show us some interesting places in the Korean quarter, places which even I don't know yet. I had already hired a barge to take us out there and to have a drink on the river. I'll go now and tell them it's all off." He rose.

"Well," Ma Joong remarked judiciously, "we can always try to wake him up for you and make him see reason."

"I tried," Kim Sang said, "but I warn you he is in a vile temper." Ma Joong poked Po Kai in his ribs, then dragged him up from the table by his collar.

"Wake up, brother!" he bellowed in his ear. "Off to the winc and the wenches!"

Po Kai looked at them with bleary eyes.

"I reiterate," he spoke carefully with a thick tongue, "I re-iterate that I despise you. Your company is degrading, you are nothing but a bunch of dissolute drunkards. I will have no truck with you, with none of you!"

He laid his head on the table again. Ma Joong and Chiao Tai guffawed.

"Well," Ma Joong said to Kim Sang, "if that's the way he feels, you'd better leave him alone!" To Chiao Tai he added, "Let us have a quiet drink here. I estimate that Po Kai'll have sobered up by the time we leave."

"It seems a pity to call off the trip just because of Po Kai," Chiao Tai said. "We have never been to the Korean quarter. Why not take us along instead, Kim Sang?"

Kim pursed his lips.

"That won't be easy," he replied. "You'll have heard that there's an understanding that the Korean quarter has more or less its own jurisdiction. The personnel of the tribunal is not supposed to go there unless the warden asks for their assistance."

"Nonsensel" Chiao Tai explained. "We can go there incognito. My friend and me will take off our caps and bind up our hair, and nobody'll be the wiser."

Kim Sang seemed to hesitate, but Ma Joong shouted, "Good idea, let's go!"

As they were rising, Po Kai suddenly looked up.

Kim Sang patted him on the shoulder and said soothingly, "You'll have a nice rest here and sleep off the effects of the amber liquid."

Po Kai sprang up, overturning his chair. Pointing a wavering finger at Kim Sang, he shouted, "You promised to take me, you treacherous lecher! I may seem drunk to you, but I am not a man to be trifled with!" He resolutely picked up a wine jug by the neck and waved it threateningly at Kim Sang.