"You mean to tell me you can't read it? It's in dwarvish. You're a dwarf. You want some tips on beard maintenance next?"
Against Balin's wishes, Thorin hands Lord Elrond the map. Elrond recognizes Erebor immediately, but when he asks why they want the map translated, Gandalf lies for the Company and says the interest is "mainly academic." The map is in ancient dwarvish, and written in moon runes. Fortunately, Elrond can read both. The runes were written on a midsummer's eve in the light of a crescent moon, long ago; fortunately, the same moon shines tonight. Elrond reads: "Stand by the gray stone when the thrush knocks, and the setting sun with the last light of Durin's Day will shine upon the key-hole." Bilbo asks about Durin's Day, and is told by Gandalf that it is a dwarven holiday when the last moon of autumn and the first sun of winter are in the sky together. Thorin laments that time is running short, but Balin claims they still have time to find the door. Elrond realizes the dwarves' intent, and warns them that it would be unwise.
The Book: The elves tease Thorin for his beard, and Bilbo for his fat stomach, as Thorin's Company makes its way to Rivendell. The dwarves stayed at the Last Homely House for two weeks, and just sort of sat around - "there is little to tell about their stay." They took the time to grow refreshed, and mend their clothes and tempers. Elrond examines Orcrist and Glamdring, and mentions that they must have come from a dragon's hoard or a goblin plunder, since dragons and goblins destroyed the city of Gondolin long ago. Thorin promises to keep the sword in honor. Elrond asks for the map, and is given it. He disapproves of dwarvish love for gold, but still agrees to read it. He notices the moon runes for the first time, and says they "must have been written on a midsummer's eve in a crescent moon, a long while ago." His translation of the runes is word-by-word the same as in the movie. Elrond asks about Durin's Day, and Thorin says it is when "the last moon of Autumn and the sun are in the sky together." The next morning, Thorin's Company leaves Rivendell and makes way for the Misty Mountains.
What difference does it make? A lot of little changes here, but things are mostly kept the same. The small differences are on topics we've already covered, like the silly nature of the book's elves, and Thorin's barely contained anti-elven prejudice. Bilbo has no designs on discovering the history of his sword in the novel, either. One of the biggest changes is the length of time Thorin's Company stays in Rivendell. In the movie, they stay a single night. In the book, they're there for two weeks. This is consistent with Peter Jackson's decision to play up the friction between dwarves and elves; they'd have no desire to stay at Rivendell any longer than stricly necessary.
Lucky for Bilbo. Thorin's bigotry was starting to get super embarrassing.
My Opinion: While I like the increased animosity between dwarves and elves, I found some of the movie's attempts at humor in this scene a little cringe-worthy. The implication that elves are vegetarians is an odd one, too; they eat meat in the books (later chapters explictly reference the smell of cooking meat in an elven outpost), so why the change? I prefer Oin's reaction to hearing the flute. There's no need to create differences between the two cultures, Peter Jackson, there's plenty of reasons for them to dislike one another already. The decision to keep the dwarves at Rivendell for only a day was a wise one, too, in my opinion. Both because it fits with the racial tensions, and for narrative purposes - I'm really not interested in seeing fourteen days of rest.