The text authority page lists both as authors, but Whittle first. On looking at all the page scans, I'm inclined to think that the evidence strongly suggests Russell should get the top billing. At most El Nathan, writing in collaboration with James McGranahan, may have come up with the "Hallelujah, hallelujah, hallelujah to His name" refrain, whereas Russell probably wrote all (or at least 7 of) the stanzas, and may have written the "Sing we Alleluia" refrain. (And FWIW, my own favorite is the setting to VENI EMMANUEL, with an entirely different refrain.)
Comments
Whittle >> Russell
Unless someone objects soon, I'm going to go in with my editing skills and see if I can rewrite the text authority to reflect what appears to be the situation. I just wish I were more certain of Whittle's role. It occurs to me that (since the sort of hymnals Whittle's stuff mostly appeared in early on were not always carefully edited, and the line between "Author" and "Composer", especially where refrains were concerned, was not always clearly marked, it's possible that Whittle was author of the "Hallelujah, hallelujah, hallelujah to His name" refrain, and composer of the associated tune... but I don't know how to be sure.