William Walker, Organist

I don't know what started this bit of research but I remembered hearing of a friend of my Grandfather called William Walker who was quite famous as an organist and composer; the only other detail I remember was that he was blind. With a bit of Googling I discovered that there was a William Walker who was listed in an publication around 1855 . He was Organist in 100 Constitution St (Town Hall) Leith. but have not found out anything else. Was he a blind composer I wonder?