Ah, but it's mostly other peoples' knowledge!

There are indeed three verses to this song. Kenneth Peacock (Songs of the Newfoundland Outports, II, 520-1) prints a version from tradition and also quotes the original text, written by E H Milligan for the book Songs of the Irish Harpers (1910). Father O'Neill's militant verses, written a few years later, have rather eclipsed Milligan's in the popular imagination; they get quoted here at the slightest mention of the word "foggy". The well-known tune, of course, is older (though Grattan Flood's assertion, made without evidence -as usual- that it is "certainly" as old as the year 1595" is probably mere wishful thinking).

I don't think that Milligan's song has ever been quoted here in full, so I'll do that as soon as time allows; unless someone who has it to hand would like to do it sooner.