Sorry, I misremembered. It's not a book from the mid-20th century, but the beginning of the century ('The Minstrelsy of England', vol. 2, by Edmondstoune Duncan, Augener, 1909). His complete note on the song is:
'The ballad and air are quoted from 'Wit and Mirth' (1719), vol. v., p. 80 - a reprint of the piece which first appeared in the edition of 1707, vol iii., p. 156. It was familiar a generation ago to country singers.'
The words are as follows:
Did you not hear of a gallant sailor, Whose pockets they were lined with gold, He fell in love with a pretty creature, As I the truth to you unfold; With kind salute, and without dispute, He thought to gain her for his own, Unconstant woman proves true to no man, She's gone and left me all alone.
Don't you remember my pretty Peggy, The oaths and vows you made to me, All in the chamber we were together, That you would ne'er unconstant be; But you prove strange love, and from me range, And leave me here to sigh and moan, Unconstant woman is true to no man, She's gone and left me all alone.
When first I saw your charming beauty, I stood like one all in amaze, I studied only how to pay duty, And could not speak but only gaze; At last said I, O fair maid comply, And ease a wretched lover's moan, Unconstant woman proves true to no man, She's gone and left me here alone.
Since Peggy has my kindness slighted, I'll never trust a woman more, 'Twas she alone who e'er me delighted, But since she's false I'll leave the shore; In ship I'll enter, on seas I'll venture, And sail the world where I'm not known, Unconstant woman proves true to no man, She's gone and left me here alone.
I'd also be interested in any alternative song set to the same tune, as it's a particularly nice one. I give the first 2 lines: there are 3 beats in a bar and all the notes are either crotchets (c) or quavers (q), all within the same octave of the scale. The first strong beat is the 4th note: