In previous chapters, Huck describes his and Jim's idyllic life on the island, free of society. When a thunderstorm rolls in, Huck describes it in almost mythological dimensions,
...then a perfect ripper of a gust would follow along and set the branches to tossing their arms as if they was just wild; and next, when it was just about the bluest and blackest—fst! it was as bright as glory, and you'd have a little glimpse of tree-tops a-plunging about away off yonder in the storm, hundreds of yards further than you could see before; dark as sin again in a second, and now you'd hear the thunder let go with an awful crash, and then go rumbling, grumbling, tumbling, down the sky towards the under side of the world, like rolling empty barrels down-stairs—
Further, the freedom of the river is conveyed in these words from Chapter XII, which could easily be titled, "The Wild, Free River"
It was kind of solemn, driftin' down the big still river, laying on our backs looking up at the stars, and we didn't ever feel like talking lous, and it warn't often that we laughed, only a little kind things, and nothing ever happened to us at all, that night, nor the next, nor the next.
As they pass towns, Huck describes each as "a shiny bed of nights" except when they pass St. Louis, and then Huck says "the whole world lit up." To Huck, the raft and Jim have become his world, a world of freedom and friendship. Because Jim has built a wigwam in the center of the raft, they have shelter from the rains. Moreover, they have a secluded little world inside the wigwam, safe from the mystery of the night and the storms. Thus, the wigwam that Jim builds represents secluded safety and frienship and would, therefore, be a good symbol for Chapter XII. For a time, Huck loses his beloved raft as he is tempted to investigate the shipwrecked boat, the Walter Scott. There, on the boat, Huck overhears the perpetrators, who have come to eliminate one of their number, Jim Turner. Fortunately, the raft shows up again as Huck and Jim head downstream.