Frank Henninger's useful riposte is a reminder that a computer will do
exactly what you tell it to do, but it won't think for you.

As we reported, when we searched for "sold down the river" in the
University of Virginia's electronic texts we got four hits, all in the
text of Pudd'nhead Wilson.  Now, in view of Mr. Henninger's experience,
we made another search, this time for the word "sell" with a boolean link
to the word "river" provided the words were within 40 characters of each
other.

Within these parameters there are indeed two hits in Huckleberry Finn:
"and so she'd sell him straight down the river again" and "was going to
sell him down the river, and said so . . . ."

But, even more wonderful, there are eleven additional hits in Pudd'nhead
Wilson, all using the word "sell," not "sold."  Therefore, it is safe to
say that the CONCEPT of being sold down the river appears at least
fifteen times in Pudd'nhead Wilson--possibly more, if more subtle
searches can be devised.

A secondary moral to the story seems to be that when one uses a printed
concordance the propinquity of such entries as "sold" and "sell" would
cause one to look up both.  Or, it is possible the maker of the
concordance would have combined both as relating to a single concept.
Electronic searching requires the searcher to be more self-aware of the
possible verbal permutations of the concept sought.

Charles & Mary Boewe