"What" and "Not"

Mr. Knott was a worker. He worked in a big factory in London. He lived a long way from the factory. So he was usually quite tired when he got home.

At half past nine one evening, when he was just in bed, the telephone rang in the hall of his house. He went downstairs, picked up the telephone and said, "This is White Street 2876. Who is speaking, please?"

"Watt," a man answered.

"What's your name, please?" said Mr. Knott.

"Watt's my name," was the answer.

"Yes, I asked you that. What's your name?" Mr. Knott said again.

"I told you, Watt's my name," said the other man.

"Are you Jack Smith?"

"No, I'm Knott," answered Mr. Knott.

"Will you give me your name?" said Mr. Watt.

"Will Knott," answered Mr. Knott.

Both Mr. Watt and Mr. Knott put their telephones down angrily and thought, "That must be a mad man!"