> I was wondering if someone can tell me how many books Thomas Jefferson donated to the
> National Library after the British burned it down.  All I know is that Jefferson 
> donated all of his books from his personal library.

Actually, Jefferson sold his books to the national government, forming the Library of Congress.
The Library of Congress has a special online exhibit on Jefferson's 
collection, and it has the exact number of books he provided.  There is a webpage
devoted to the books provided by Jefferson at:

 http://lcweb.loc.gov/exhibits/jefferson/jefflib.html


According to  gopher://marvel.loc.gov/00/loc/history:

"In 1814, the British army
invaded the city of Washington and burned the Capitol, including
the 3,000 volume Library of Congress. By then retired to
Monticello, Jefferson offered to sell his personal library, the 
largest and finest in the country, to the Congress to
"recommence" its library. The purchase of Jefferson's 6,487
volumes for $23,940 was approved in 1815."