The Hobbit

He found all their twelve cells in different parts of the palace,
     and after a time he got to know his way about very well. What was his surprise one day to overhear some of the guards talking
     and to learn that there was another dwarf in prison too, in a specially deep dark place. He guessed at once, of course, that
     that was Thorin; and after a while he found that his guess was right. At last after many difficulties he managed to find the
     place when no one was about, and to have a word with the chief of the dwarves.
    Thorin was too wretched to be angry any longer at his misfortunes, and was even beginning to think of telling the king all
     about his treasure and his quest (which shows how low-spirited he had become), when he heard Bilbo’s little voice at his keyhole.
     He could hardly believe his ears. Soon however he made up his mind that he could not be mistaken, and he came to the door
     and had a long whispered talk with the hobbit on the other side.
    So it was that Bilbo was able to take secretly Thorin’s message to each of the other imprisoned dwarves, telling them that
     Thorin their chief was also in prison close at hand, and that no one was to reveal their errand to the king, not yet, nor
     before Thorin gave the word. For Thorin had taken heart again hearing how the hobbit had rescued his companions from the spiders,
     and was determined once more not to ransom himself with promises to the king of a share in the treasure, until all hope of
     escaping in any other way had disappeared; until in fact the remarkable Mr. Invisible Baggins (of whom he began to have a
     very high opinion indeed) had altogether failed to think of something clever.
    The other dwarves quite agreed when they got the message. They all thought their own shares in the treasure (which they quite
     regarded as theirs, in spite of their plight and the still unconquered dragon) would suffer seriously if the Wood-elves claimed
     part of it, and they all trusted Bilbo. Just what Gandalf had said would happen, you see. Perhaps that was part of his reason
     for going off and leaving them.
    Bilbo, however, did not feel nearly so hopeful as they did. He did not like being depended on by everyone, and he wished he
     had the wizard at hand. But that was no use: probably all the dark distance of Mirkwood lay between them. He sat and thought
     and thought, until his head nearly burst, but no bright idea would come. One invisible ring was a very fine thing, but it
     was not much good among fourteen. But of course, as you have guessed, he did rescue his friends in the end, and this is how
     it happened.
    One day, nosing and wandering about, Bilbo discovered a very interesting thing: the great gates were
not
the only entrance to the caves. A stream flowed under part of the lowest regions of the palace, and joined the Forest River
     some way further to the east, beyond the steep slope out of which the main mouth opened. Where this underground watercourse
     came forth from the hillside there was a water-gate. There the rocky roof came down close to the surface of the stream, and
     from it a portcullis could be dropped right to the bed of the river to prevent anyone coming in or out that way. But the portcullis
     was often open, for a good deal of traffic went out and in by the water-gate. If anyone had come in that way, he would have
     found himself in a dark rough tunnel leading deep into the heart of the hill; but at one point where it passed under the caves
     the roof had been cut away and covered with great oaken trapdoors. These opened upwards into the king’s cellars. There stood
     barrels, and barrels, and barrels; for the Wood-elves, and especially their king, were very fond of wine, though no vines
     grew in those parts. The wine, and other goods, were brought from far away, from their kinsfolk in the South, or from the
     vineyards of Men in distant lands.
    Hiding behind one of the largest barrels Bilbo discovered the trapdoors and their use, and lurking there, listening to the
     talk of the king’s servants, he learned how the wine and other goods came up the rivers, or over land, to the Long Lake. It
     seemed a town of Men still throve there, built out on bridges far into the water as a protection against enemies of all sorts,
     and especially against the dragon of the Mountain. From Lake-town the barrels were brought up the Forest River. Often they were just tied together like big rafts and poled or rowed up the stream; sometimes