Fragment from a letter written by Robert Burns

This is the address panel from a letter written by Robert Burns to his friend and editor, George Thomson in Edinburgh, who was Clerk to the Board of Trustees for Encouragement of Art and Manufacture in Scotland.  The rest of the letter has not survived.   George Thomson was the editor of "A Select Collection of Original Scottish Airs".  Burns made a major contribution to this work and spent the last years of his life preparing and writing songs for Thomson.  Perhaps this letter contained some.  There is a note of authentication by George Thomson on the reverse.  The fragment must have been requested by an admirer of the poet who wished for an example of his handwriting.