Read the passage, in which Huck tells about how he and the duke escaped to the raft.

I done it, and [the duke] done the same. We struck the raft at the same time, and in less than two seconds we was gliding down stream, all dark and still, and edging towards the middle of the river, nobody saying a word. I reckoned the poor king was in for a gaudy time of it with the audience, but nothing of the sort; pretty soon he crawls out from under the wigwam, and says:

‘Well, how'd the old thing pan out this time, duke?’ He hadn't been up–town at all.

What makes this passage humorous?