Still and all, the thread from which Dennis has quoted my closing comments ( Origins: Peggy Gordon ) was started by you with that very songster text. I added a reference to a very similar text from a songsheet of around the same date, which also included music. That music being very different from the published examples from later Nova Scotia oral tradition (as most of us know, Mrs Gallagher used the melody usually associated with 'Banks of the Sweet Primroses'), it would seem most likely that the vaudeville collage of floating verses found its way to Nova Scotia (and a few other places; in the thread cited, John Moulden referred to a version noted in West Virginia as 'Maggie Goddon') on printed songsheets without music.

The popularity of 'Peggy Gordon' in the Revival over the last forty years or so has led many people to assume that it 'must' have been known in that form in British or Irish tradition prior to the publication of Helen Creighton's book. There is no evidence at all of that, and no reason to suppose that any of the recordings of the song by popular revival performers like the Corries are anything but arrangements of the song as published by Miss Creighton (whether learned directly from the book or via other revival performers), as opposed to being independent 'versions' in their own right.

That is not a value judgement, but a general reminder that such recordings can by definition tell us nothing about what Mr Smith understood by 'Ingo'; only what later interpreters guessed he had meant. So far we have no other example from tradition that uses anything remotely resembling the word, so all answers to the original question must necessarily be guesses; it would be fatuous to pretend otherwise. Some guesses are likely to be better-informed than others, as this discussion clearly illustrates. Some guesses, indeed, are so desperately unlikely that other people have begun deliberately to post facetious 'answers'; it is not always easy to tell the difference.