about 4 o'clock
What time shall I return for Olga ? '' `` It grows dark quickly , '' Karl said , looking at his watch . `` In another hour we shall not be able to see . Suppose you return about 4 o'clock . '' `` Very well ; and now I must be going . You are coming to the ball to-night , Karl ? You know you really are the guest of honor ; is n't he , Olga ? ''