The American Antiquarian Society (AAS) Historical Periodicals Collection contains periodicals from 1684-1912. While the collection is not comprehensive, it contains samplings of the AAS's vast holdings of materials. This is a great resource to use to find primary resources in American history.
This collection of legal materials on the issue of slavery includes federal, state, and local statutes on slavery, plus all reported state and federal cases. Also included are books and pamphlets written about slavery, including defenses of it and attacks on it, and congressional testimony and debates on the topic.