I was searching for the lyrics, found this thread, and am much the wiser, thanks to you all.

The first two lines of the third stanza -

'Tis a sigh that is wafted across the troubled wave 'Tis a wail that is heard upon the shore

- lend credence to those who have suggested that the song is about the plight of the Irish during the potato famine.

The "sigh that is wafted across the troubled wave" implies news of distress from the homeland, and the "wail that is heard upon the shore" refers to the exodus to America. "The troubled wave" means the Atlantic Ocean, by virtue of the literary device synecdoche, which substitutes the part for the whole. Between England and America, it certainly had been a troubled bit of water in Foster's lifetime.

Thanks for the perspective, folks.

RM