Well, it is very fortunate that I came across this question, as I am a world expert in Dwarven runes! There isn't much calling for it here on normal earth (as opposed to Middle Earth, where my services are very much in demand), so there aren't many experts here. The question you ask refers to Thror's map that points the way to The Desolation of Smaug and the Lonely Mountain where the old dwarven treasure trove was appropriated by Smaug. The runes that are written on the left-hand side of the map provide a key clue to the secret passage through which the dwarves and Bilbo gain admittance to the mountain. They can be translated as follows:
Five feet high the door and three may walk abreast.
I have included a link below to a page that talks about the runes in more depth. Hope this helps!