And at last, sure enough, [...] the horse broke loose, and away he went like the very nation, round and round the ring...
Next, in chapter, 23:
"But dis one do SMELL so like de nation, Huck."
There are also different uses of "the nation" in the book, for example in chapter 2:
but how in the nation are these fellows going to be ransomed if we don't know how to do it to them?
The last use is more common in the book, and does make more sense - "the nation" seems to refer to a large area, similar to the modern "how in the world" or "how on earth".
I can't really figure out the first two though - in both cases "the nation" seems to refer to something negative... What is the meaning of this idiom?
Note about the quotes - in all cases I have added the emphasis, and all the rest of the mistakes are [sic]. It is not an easy book to read.