about six o'clock
They were now able to tell the difference between night and day by the temperature . The air that came through the holes in the ceiling was a little cooler by night , enough for senses trained to preternatural acuteness by long imprisonment to tell it . The guard always came about eight o'clock with Ned 's supper and they chose that time for the attempt . Obed White entered Ned 's cell about six o'clock . The boy could scarcely restrain himself and the man 's blue eyes were snapping with excitement . But Obed patted Ned on the shoulder . `` We must both keep cool , '' he said .