Hi Kathy! See *Life on the Mississippi* Chapter L, "The 'Original Jacobs'" where Twain discusses Isaiah Sellers. "The old gentleman was not of literary turn or capacity, but he used to jot down brief paragraphs of plain, practical information about the river, and sign them "MARK TWAIN," and give them to the New Orleans *Picayune*." Cordially, Encyclopedia Vern :D