the appeal of Porter and Emory to romancers like Melville

William Henry Babcock on the kind of books to be found in a private Maryland library:

There are also Porter's very frank narrative of experiences in the South Seas, which must have prompted Herman Melville's "Omoo" and "Typee," and Emory's business-like chronicle of Kearney's old New Mexican campaigns, in which I think I can discover the germs of Mayne Reid's southwestern tales.  --Lippincott's Monthly Magazine 42 -1888

Babcock of course refers to David Porter's Journal of a Cruise Made to the Pacific Ocean, indeed one of Melville's early source-books, and William H. Emory's Notes of a Military Reconnaissance.

Gen. William H. Emory ca. 1860-1865