In the chapter on the Pilot's Monopoly, he notes that wages rose from $100
per month to $125 as business picked up, and then in full busy season rose
to $250/ mo. which is the threshhold figure set by the association. But as
the association grew in ranks, and the owners had no choice but to hire
them. He notes:
"When the pitlots' association announced, months before hand, that on the
first day of September 1861, wages wold be advanced to five hundred dollars
per month, the owners and captains instantly put freight up a few cents, and
explained to the farmers along the river the necessity of it, by calling
their attention to the burdensome rate of wages about to be established"
(LOM, Penguin edition, p. 136).
The inflation calculator at http://www.westegg.com/inflation/ shows $500 in
1861 to be equal to $10, 271.33 -- not a CEO's salary by any means but
rather fitting the lofty status Twain claimed pilots deserved. Whether that
was what he earned is not entirely clear. Perhaps someone who has
researched his piloting career can confirm if his earnings matched the
figures he cites in LOM.