but it 's bells at twenty-seven thousand feet as the plane breaks into the clear again , as its motion steadies again ; it is bells ; it is the bell as ben hanscom sleeps ; and as he sleeps the wall between past and present disappears completely and he tumbles backward through years like a man falling down a deep well-wells 's time traveller , perhaps , falling with a broken iron rung in one hand , down and down into the land of the morlocks , where machines pound on and on in the tunnels of the night .