
[ Disclaimer: The picture of "Gladness" is at Huish Epsicopi church, in Langport where the psalms were written, but the action of the video is not there. ] Gladness was one of the Rev James Moreton's tunes published in 1860, apparently to fit Milton's psalm 136. We now include ACTUAL SINGING of 2 verses (at the end). A descendant wrote modern words to challenge Milton's in 2009. More info on video. Sing!
There is a little more about James Moreton's hymnbook in the Wikipedia entry for Langport. There is a rare copy in the British Library (in London). His descendant's 2009 hymnbook "Thought-provoking Hymns for our Times" has never been published.