The link doesn't work..but thanks..
Found an interesting thing in the book I'm reading, No Chariot Let Down, concerning definition of *white person*, which also explains a lot. This is from the 1860 time period:

"There was no firm legal definition of a white person....'Whenever the African taint is so far removed, that upon inspection a party may be fairly pronounced to be white, and such has been his or her previous reception into society, and enjoyment of the privileges usually enjoyed by white people, the Jury may rate and regard the party as white...When the Negro blood is reduced to, or below 1/8, the Jury ought always to find the party white...When the blood is 1/4 or more African, the Jury must find the party Mulatto.' The decision in any particular case was always in the hands of a jury, which, despite the flexibility and ambiguity of the law, tended to adopt the one drop rule. Thus in Charleston and elsewhere, individuals who were visibly white were socially and legally colored..."