midnight
He could not find them , yet he was sure he had left them on a shelf in the tower . `` I wonder if the ghost took them , '' he said . He heard some one coming up the iron stairs of the small companionway that led down into the interior of the ship through the man-hole . At first he thought it was his queer midnight visitor returning . Then the head and shoulders of Jack appeared . `` I 've come to relieve you , '' said Jack . `` Your watch is up ; it 's two o'clock .