"It's no kid and it's no pet," said Rubin stubbornly. "I wish you wouldn't all assume I don't know what I'm hearing. Listen, I worked in a lumberyard once. I'm a pretty fair carpenter myself. I know the sound of a hammer on wood."

"Maybe someone's doing some home repairs," said Halsted.

"For months? It's more than that."

Henry said, "Is that where the situation stands now?

Did you make any other effort to find the source after the doorman failed you?"

Rubin frowned. "I tried but it wasn't easy. Everyone has an unlisted number around here. It's part of the fortress mentality Avalon talks about. And I only know a couple of people to talk to. I tried knocking on the most likely doors and introducing myself and asking and all I got were hard stares."

"I'd give up," said Drake.

"Not I," said Rubin, tapping himself on the chest. "The main trouble was that everyone thought I was some kind of nut. Even Charlie, I think. There's a kind of general suspicion about writers on the part of ordinary people."

"Which may be justified," said Gonzalo.

"Shut up," said Rubin. "So I thought I would present some concrete evidence."

"Such as?" asked Henry.

"Well, by God, I recorded the damned banging. I spent two or three days keeping my senses alert for it and then, whenever it started, I tripped the switch and recorded it. It played hell with my writing but I ended up with about forty-five minutes of banging-not loud, but you could hear it. And it was an interesting thing to do because if you listened to it you could tell just from the banging that the bum is a rotten carpenter. The blows weren't even and strong. He had no control over that hammer, and that kind of irregularity wears you out. Once you get the proper rhythm, you can hammer all day without getting tired. I did that many a time-"

Henry interrupted. "And did you play the recording for the doorman?"

"No. A month ago I went to a higher court."

Gonzalo said, "Then you did see the super?"

"No. There's such a thing as a tenants' organization."

There was a general smile of approval at the table which left only Henry untouched. "Didn't think of that," said Avalon.

Rubin grinned. "People wouldn't in a case like this. That's because the only purpose of the organization is to

get after the landlord. It's as though no one ever heard of a tenant annoying another tenant and yet I'd say that nine-tenths of the annoyances in an apartment house are caused by tenant-tenant interactions. I said that. I-"

Henry interrupted again. "Are you a regular member of the organization, Mr. Rubin?"

"I'm a member, sure. Every tenant is a member automatically."

"I mean do you attend meetings regularly?"

"As a matter of fact, this was only the second meeting I'd attended."

"Do the regular attendees know you?"

"Some of them do. Besides, what difference does that make? I announced myself. Rubin, I said, 14-double-A, and I made my speech. I had my tape recording with me and I held it up and waved it. I said that was the proof some damn fool was a public nuisance; that I had it labeled with dates and times and would have it notarized if necessary and see my lawyer. I said that if the landlord had made that noise, everyone in the audience would be howling for united action against the nuisance. Why not react the same to one of the tenants?"

"It must have been a most eloquent address," growled Trumbull. "A pity I wasn't there to hear you. What did they say?"

Rubin scowled. "They wanted to know who was the tenant who made the noise and I couldn't tell them. So they let it drop. Nobody heard the noise; anyway, nobody was interested."

"When did the meeting take place?" asked Henry.

"Nearly a month ago. And they haven't forgotten about it, either. It was an eloquent address, Tom. I fried them. I did it deliberately. The word was going to spread, and it did. Charlie the doorman said he heard half the tenants talking about it-which was what I wanted. I wanted that carpenter to hear it. I wanted him to know I was after him."

"Surely you don't intend violence, Mr. Rubin," said Henry.

"I don't need violence. I just wanted him to know. It's been pretty quiet the last few weeks, and I'll bet it stays quiet."

"When's the next meeting?" asked Henry. "Next week… I may be there."

Henry shook his head. He said, "1 wish you wouldn't, Mr. Rubin. I think it might be better if you dropped the whole thing."

"I'm not scared of whoever it is."

"I'm sure you're not, Mr. Rubin, but I find the situation peculiar on several counts-" "In what way?" asked Rubin hastily. "I-I- It seems melodramatic, I admit but- Mr. Avalon, you and Dr. Drake arrived downstairs in the lobby just ahead of me. You spoke to the doorman." "Yes, that's right," said Avalon.

"Perhaps I came too late. I may have missed something. It seems to me, Mr. Avalon, that you asked the doorman if there had been any incidents of a distressing nature in the apartment house and he said there had been a robbery in a twentieth-floor apartment the last year and that a woman had been hurt in some fashion in the laundry room."

Avalon looked thoughtful and nodded.

Henry said, "Yet he knew that we were heading for Mr. Rubin's apartment. How is it that he didn't mention that this apartment had been broken into only two weeks before?"

There was a thoughtful pause. Gonzalo said, "Maybe he didn't like to gossip."

"He told us about other incidents. There might have been a harmless explanation, but when I heard of the break-in, I grew perturbed. Everything I've heard since has increased my feeling of uneasiness. He was a fan of Mr. Rubin. Mrs. Rubin had turned to him at the time. Yet he never spoke of it."

"What do you make of it, Henry?" asked Avalon.

"Is he involved, somehow?"

"Come on, Henry," said Rubin at once. "Are you trying to say Charlie is part of a holdup ring?"

"No, but if there is something peculiar going on in this apartment house, it might be very useful to slip the doorman a ten-dollar bill now and then. He might not know what it's for. What is wanted may seem quite harmless to him-but then when your apartment is invaded, it may be that he suddenly understands more than he did before. He feels involved and he won't talk of it any more. For his own sake."

"Okay," said Rubin. "But what would be so peculiar going on here? The carpenter and his banging?"

Henry said, "Why should someone haunt the floor waiting for you and Mrs. Rubin to leave the apartment untenanted and single-locked? And why, when Mr. Avalon mentioned the matter of the woman in the laundry early in the evening, Mr. Rubin, did you promptly dismiss the matter with some reference to the Chinese delegation to the United Nations. Is there a connection?"

Rubin said, "Only that Jane told me some of the tenants were worried about the Chinese getting in here."

"Somehow I feel that is too weak a reason to account for your non sequitur. Did Mrs. Rubin say that the man she had surprised in the apartment was an Oriental?"

"Oh, you can't go by that," said Rubin, drawing his shoulders into an earnest shrug. "What can anyone really notice-"

Avalon said, "Now wait a while, Manny. No one's asking you if the burglar was really Chinese. All Henry is asking is whether Jane said he was."

She said she thought he was; she had the impression he was… Come on, Henry. Are you proposing espionage?"

Henry said stolidly, "Combine all this with the matter of the irregular banging-I believe Mr. Rubin mentioned the irregularity specifically as the sign of a poor carpenter. Might the irregularity be the product of a clever spy? It seems to me that the weak point of any system of espionage is the transfer of information. In this case, there would be no contact between sender and receiver, no intermediate checkpoint, nothing to tap or intercept. It would be the most natural and harmless sound in the world that no one would hear except for the person listening-and, as luck would have it, a writer trying to concentrate on his writing and distracted by even small sounds. Even then it would be considered merely someone hammering-a carpenter."