The Practical Banjo Method Books 1 & 2 by H. C. Blackmar have been added to the BANJO TUTOR BOOKS library. Also "Ten Favourite Banjo Tunes" compiled and arranged by H. C. Blackmar; and "H. C. Blackmar's Banjo Duets" part 3 - 12 No.s Dance and Modern Opera.
I found these on the Library of Congress web page. Some pages were missing but may be blank because all the pieces and exercises listed in the contents, page 33 of Book 2, are present.