For correspondence between Twain and Barnum, you might want to track down the items listed in Paul Machlis's _Union Catalog of Clemens Letters_ and _Union Catalog of Letters to Clemens_ (both U of California Press). There are several hits for Barnum in both books. There's an entry for Barnum in the _MT Encyclopedia_ (Garland, 1993), which unfortunately doesn't tell much about his relationship with Twain--but maybe the items listed in the bibliography of that entry will lead to something more. Hope this helps! Taylor Roberts University of British Columbia