SCENE: A sitting-room in a small house in a London suburb. The window is in the wall to the left of the spectator and the door in the right half of the back wall. The furniture is ordinary. On the chimneypiece, to the right of the spectator, is a clock. The room is lit by electric light. It is some time after the evening meal. Mr Perkins is reading a newspaper. Mrs Perkins is darning a sock, and Miss Perkins is engaged upon a jigsaw puzzle.MRS PERKINSWhat...