all about the back-door, as the goblins called the lower gate, where Bilbo lost his buttons. As a matter of fact it was well known to anybody who was acquainted with this part of the mountains; but it took a wizard to keep his head in the tunnels and guide them in the right direction. “They made that gate ages ago,” he said, “partly for a way of escape, if they needed one; partly as a way out into the lands beyond, where they still come in the dark and do great damage. They guard it always and no one has ever managed to block it up. They will guard it doubly after this,” he laughed.
