Here is Graves's once highly admired poem, from his "Irish Songs and Ballads" (1880), p. 14:
THE FOGGY DEW
Oh! a wan cloud was drawn O'er the dim, weeping dawn, As to Shannon's side I returned at last; And the heart in my breast For the girl I loved best Was beating — ah beating, how loud and fast! While the doubts and the fears Of the long, aching years Seemed mingling their voices with the moaning flood; Till full in my path, Like a wild water-wraith, My true love's shadow lamenting stood.
But the sudden sun kissed The cold, cruel mist Into dancing showers of diamond dew; The dark flowing stream Laughed back to his beam, And the lark soared singing aloft in the blue; While no phantom of night, But a form of delight Ran with arms outspread to her darling boy: And the girl I love best On my wild, throbbing breast Hid her thousand treasures, with a cry of joy.
The melody (p. 207) is that collected by Bunting in 1839 and played, for example, by Eugene O'Donnell and James MacCafferty. I have also heard it played, perversely but effectively, as a march.
I can't tell if there's a meaningful resemblance between Bunting's tune and the well-known "Ye Banks and Braes" (composed by Niel Gow - as "The Royal Caledonian Hunt's Delight" - in or before 1788), a simplified version of which often carried "The Foggy, Foggy Dew" in England.