The long-suffering professor smothered his wrath and went down into the cellar. "Are you the plumber?" he inquired of a grimy-looking person who was tinkering with the pipes.
"Yes, guv'nor," he answered.
"Been in the trade long?"
"'Bout a year, guv'nor."
"Ever made any mistakes?"
"Bless yer, no, guv'nor."
"Oh, then, I suppose it is quite all right. I imagined you had connected up the wrong pipes, for the chandelier in the drawing-room is spraying like a fountain, and the bathroom tap is on fire."