When folks write about a certain artist recording a well remembered song like Londonderry Air, I can help with the question of whether John McCormack recorded it: yes, on a song called Mary Dear (in 1932?). I do not know who wrote it but I only say that are any of you guys music teachers? The song Londonderry Air is more remembered as Fred Weatherly's 1913 song, Danny Boy, and contrary to what people think, Fred was not brought up in Ireland, but the North of England. This song has been used in others after he wrote the words that we sing today. Therw were 2 hymns written to the same tune, one called 'I Cannot Tell', which i think was written in 1928...though I can't remember who wrote it but it might have been the Scottish born John Bell.