A.B. is one of Mr. Chamberlain's Cabinet colleagues. X.Y. is
another. More specific than that I cannot be. " I see," said someone to A.B., " that you have a balloon on Horse Guards Parade to keep Ministers safe." " Yes," said A.B. " We call it X.Y. because most of the time it sits on the ground doing nothing. But occasionally they manage to get a move on it ; then it goes up in the air and wobbles."