As a literary device, nostalgia certainly helps to shore up and establish Tolkien's Middle Earth while it is new and susceptible to easy disbelief. Finally, nostalgia dominates Bilbo's thoughts and Bilbo's thoughts‹as you will find, if you read carefully‹sustain the somber mood that balances the comic burlesque of the clownish trolls. Who'd have expected gravitas from the hobbit?
Chapter 3: A Short Rest

The dwarves are not singing; they are glad to be alive and also, the respite from the rain is an improvement on the previous situation. Still, they are not singing because danger seems (and is) omnipresent in these parts. Bilbo and the dwarves ford a river and take their ponies onto a path from which they can see mountains in the distance. Gandalf leads the way and warns strict adherence to the road. They are heading for the residence of Elrond which is called the "Last Homely House" in the "fair valley of Rivendell." This House is the last one west of the Mountains. There is a good deal of traveling over ravines and through bogs before the travelers make their way into the "secret valley of Rivendell" and their spirits immediately begin to rise. Bilbo smells elves and it is not long before the sounds of the elves' songs are emanating through the scene. The tired journeyers are only too happy to get some rest, though there is a history of unpleasantness between the dwarves and the elves that must be intentionally disregarded. Inside Elrond's house, Bilbo is able to fatten himself on cakes and as long as the group stayed, Bilbo would have been happy to remain a little longer. Elrond is an old soul who has elves and "heroes of the North" as ancestors and he offers a good amount of insight regarding the quest. The group is to leave with "the early sun on midsummer morning" and when they are to leave, Elrond offers them swords of protection. One is called Orcrist, the Goblin-cleaver and another is called Glamdring, Foehammer. They are presented to Thorin and Gandalf, respectively. Looking at the map in the moonlight, Elrond is able to read moon-letters, distinct from the runes printed on the map. These words specify that the secret entrance to the Mountain can be unlocked on Durin's Day, which is the first day of the dwarves' New Year at the crux between Autumn and Winter. The travelers are well-rested when they leave but they fear that their timing, by the calendar, is horribly unlucky. Analysis:

In "A Short Rest" we get a host of archetypal images all in a jumble, most of them dreary and threatening.