midnight
asked Bluff , like most boys caring naught for grammatical rules when far away from the school room . `` My uncle ! '' replied Gilbert . `` But why under the sun is Mr. Dennison coming down here to the cabin , and at midnight , too ? '' asked Jerry . `` That 's just it , '' replied the visitor at the cabin . `` I 've known for some time that Uncle Aaron is a sleep-walker , you see . ''