For a teenage boy and an escaped slave to head south down the river in 1845 or so meant capture and re-enslavement for Jim and prison or worse for Huck for aiding him. The only practical move for them is to paddle north. Clemens had to figure out a way to keep that raft moving south to Silas's farm, and the duke and the king's commandeering of it enabled him to do just that, while also enabling him to satirize royalty, religious camp meetings, mob psychology, et cetera. These are not totally original thoughts, but were brought out in discussions at Bob Hirst's Twain course, the most fun I had at UC Berkeley. Gerald