Life on the Mississippi

According to the experts, Life on the Mississippi by Mark Twain was one of his least popular works. But after having read most of it over the last couple days, I can honestly say I don't know why. I think it's great! I especially love the middle chapters (about 4-15) where he goes into great detail about what it took to be a steamboat pilot. It was not for the faint of heart, or for those with a weak memory. The pilots had to know every inch of the river bank as well as what lay beneath the water. I can't imagine how they remembered it all! And I enjoyed the parts where Sam (Clements) would ask questions. Like how they can tell the difference between an underwater reef, and the wind, when they both produced the same looking little ripples in the surface of the water? And the pilots would answer: "You just know." It was something that you couldn't explain, but once you figured it out you just knew. A lot of piloting was like that it seems.
I also thought the book was cool because it seems to explain where Samuel Clements acquired his literary pseudonym! Apparently "mark twain" was a measurement of depth that the sailors would call out to the pilot, as they plunged a pole or weighted rope off the sides of the boat to mark the depth of the channel. "Mark" as in  "make note of" and "twain" as in the old way to designate the number two (in this case 2 fathoms or 12 feet). So mark twain literally means "make a note of the fact that there is 12 feet if water here".
For an example from the text itself where measurements were being taken and shouted back to the pilot:
"M-a-r-k three!...M-a-r-k three!...Quarter-less three!....Half twain!...Quarter twain!... M-a-r-k twain!...Quarter-less..." And so on...
Isn't that something? Clements himself says in the book that he never had a job he enjoyed more than being a steamboat pilot, and I think taking the name Mark Twain was his own way of paying homage to that time in his life. I imagine it must have been amusing to hear all the people shout "Mark Twain!" as he passed by. It kind of makes me smile anyway.