Slavery and Abolition in the US: Select Publications of the 1800s is a digital collection of books and pamphlets that demonstrate the varying ideas and beliefs about slavery in the United States as expressed by Americans throughout the nineteenth century.
http://deila.dickinson.edu/slaveryandabolition
Content-DM allows to see scans left and OCR-ed text right.
http://commons.wikimedia.org/wiki/Image:Content_DM_Dickinson.JPG