Which of these passages from The Adventures of Huckleberry Finn contains a metaphor?

Which of these passages from The Adventures of Huckleberry Finn contains a metaphor?

I reckoned Jim had fetched up on a snag, maybe, and it was all up with him. I was good and tired, so I laid down in the canoe and said I wouldn't bother no more.

I set perfectly still then, listening to my heart thump, and I reckon I didn't draw a breath while it thumped a hundred.

That was all right as far as it went, but the towhead warn't sixty yards long, and the minute I flew by the foot of it I shot out into the solid white fog, and hadn't no more idea which way I was going than a dead man.