I just received a book that is the only one that I know of that goes into
great detail about Hard Rubber and Gutta-Percha.  I have worked with Mike
Woshner on my hard rubber from Johnson's Island and he is very good at
identification of this material.  It would be a good resource for all that
have encountered it in their work.  I have set up some information on it on
my web page.  You can get to it by  going to the following:
      http://www.heidelberg.edu/~dbush/hdrbbk.html
Feel free to contact me if you have specimens of hard rubber from your 19th
century sites.  I would love to know about them.
 
 
 
*********************************************************************
David R. Bush, Ph.D
Center for Historic and Military Archaeology
Heidelberg College
310 E. Market Street
Tiffin, Ohio  44883
(419) 448-2327
FAX (419) 448-2236
mailto:[log in to unmask]
http://www.heidelberg.edu/~dbush (Johnson's Island WEBpage)
http://www.heidelberg.edu/offices/chma (Center's WEBpage)
*******************************************************************