4 o'clock
`` If you say one word more about that girl I shall fall in love with her immediately , which would be ahead of my matrimonial scheme , '' Karl replied jestingly . `` You know I am not obliged to fall in love until to-night . '' `` Well , well , I must be off , '' Herman said , as he went up to kiss Olga . `` Good-by , dear ; I shall call for you at 4 o'clock . '' Almost against his will , Karl asked a question which he had never before in all his life thought of . `` Are n't you afraid to leave your wife alone ? '' `` Alone ? ''