What Not To Use

I find it interesting to see what early textbooks tell us not to do. It gives us a fair idea of what was once "common" usage, otherwise why mention it? Lesson XXXIV in Illustrated Lessons in Our Language (Quackenbos, 1882, p. 47) presents us with these possessive pronouns.

Do not use hisn for HIS; hern for HERS;
ourn for OURS; yourn for YOURS;
theirn for THEIRS; who's for WHOSE.
These possessive forms do not take the apostrophe.

I think that most of us would consider such usage particular to parts of the deep south. It may even sound ignorant to certain (northern) ears. But it must, at one time, have been more widespread before our hard-working school-marms stamped it out.