Masato beat me here (and did a better job) at showing all the different versions, but I'll add a few things.
Lyrics above are only slightly changed from Kingsley's original poem (e.g. see here).
According to AMG, Joan Baez, Clara Butt and Richard Dyer-Bennet recorded the song with Hullah's melody, and Stan Rogers and Jill Rogoff have recorded it using a different tune by "Rogers" (Stan and Garnet, according to the album notes).
While looking this up, I just listened to the Stan Rogers & Joan Baez versions - both use the lyrics pretty much as above (Stan repeats the last phrase) - Joanie's version sounds a little more like Kingsley & 19thC, Stan's sounds a little more, well, Stan-like ...