Those that have been edited, reprinted in facsimiles, or transferred to microfilm can be borrowed through E-ZBorrow or Interlibrary Loan if they are not in Tripod. Many of them will be listed in Tripod or WorldCat under subject terms and the word "sources." For example, the search latin america* history sources produces books including:
Books printed in the 17th or 18th century are kept in libraries' rare book collections. You can go to Haverford's Special Collections, Bryn Mawr, the University of Pennsylvania, and other local libraries to see these books.
They welcome researchers from Haverford. E-mail or phone them to tell them your research needs before going over to Special Collections in the Canaday Library building.