Two boxes of letters about publication of the state's colonial records and McCrady's history of the Revolution reflect Furman's life-long interest in South Carolina history and politics. They include letters from William A. Courtenay and Edward McCrady. He wrote many letters and articles trying to track down the history of these strange people who lived in Privateer Township near Furman's plantation. The manuscripts record Furman's investigations of common Redbone family names like Goins, Chavis, and Oxendine, and his correspondence with authorities on similar and possibly related ethnic groups. One item recounts James Mooney's theory of Portuguese ancestry for the Pamunkeys, Croatans, Melungeons, and other groups.
Some items are of outstanding historical value.
Information on Reconstruction figures like Smiling is often hard to find. In 1893 J. A. W. Thomas sent Furman information on mixed breeds near Bennettsville. For generations they have claimed to have been of 'Portugese' extraction, while more commonly the white people have thought them Mulattoes. Some had fought in the Revolution and won the respect of the whites. Often, however, Furman's search yielded evidence of criminal activity.