I've come across the lyrics writer as being Katherine Tynan or Katherine Hinkson....(perhaps it is the same person...ie maiden/married names, but I can't confirm.) Unfortunately, I have no date, but I would put a more "recent" date on these lyrics compared to the "countless" others applied to the tune...What is interesting is the similarity of the lyrics you mentioned to those penned by A.P. Graves (some of the first put to the music.)

For some interesting info on Danny Boy and Londonderry Air (including Graves' lyrics, and others and a link to another site with a history of the song), visit the current Featured Song (for March) at Prof's Irish Pages... Prof's Pages http://www.prof.co.uk/irish1.htm

Sorry I couldn't give you more specific info!

Cheers!

Mary