An examiner at Edinburgh University had made himself obnoxious by warning the students against putting their hats on his desk. The university in the Scottish capital is remarkable for a scarcity of cloak rooms, and in the excitement of examinations hats are, or used to be, flung down anywhere.
The examiner announced one day that if he ever found another hat on his desk he would rip it up. The next day no hats were laid there when the students assembled. Presently, however, the examiner was called out of the room. Then some naughty undergraduate slipped from his seat, got the examiner's own hat, and placed it on his desk. When the examiner re-entered the hall, every eye was fixed upon him. He observed the hat, and a gleam of triumph shot across his face.
"Gentlemen," he said, "I told you what would happen if this occurred again." Then he took his penknife from his pocket, opened it, and blandly cut the hat in pieces, amidst prolonged applause. What he said when he discovered that he had destroyed his own hat the story does not say.