You might find digging through "The Pamphleteer" (London, early 1800's) = 
useful. The first mention of debates on copyrights, etc. that I've come = 
across was found there. For example, Anon: "An address to Parliament of = 
Great Britain on the Claims of Authors to THeir Own Copy-right" (Vol 2, = 
1813, pp. 170-202). Also, Anon: "The Case between the Public Libraries = 
and the Booksellers" (Same, pp. 341-68) 
  
While not HET proper (as these essays were written contemporaneous to = 
the events described), they do provide a setting for the early debates = 
over intellectual property rights. 
  
Hope this helps a bit. 
  
John Henry