eleven o’clock
`` The windows of the three rooms open out upon the lawn . That fatal night Dr. Roylott had gone to his room early , though we knew that he had not retired to rest , for my sister was troubled by the smell of the strong Indian cigars which it was his custom to smoke . She left her room , therefore , and came into mine , where she sat for some time , chatting about her approaching wedding . At eleven o'clock she rose to leave me , but she paused at the door and looked back . ``` Tell me , Helen , ' said she , ` have you ever heard anyone whistle in the dead of the night ? ' ``` Never , ' said I. ``` I suppose that you could not possibly whistle , yourself , in your sleep ? ' ``` Certainly not .