Which Christian denomination removed trinitarian language from the hymn "Holy, Holy, Holy"? In a brief article on the Trinity by Gordon H. Clark, he makes a surprising claim about a popular trinitarian hymn:


  The hymn book of one denomination has rewritten "Holy, Holy, Holy," so as to exclude all reference to "God in Three Persons, Blessed Trinity."


I'd like to know what hymn book and denomination he's referring to.  Wikipedia doesn't mention any such rendition, and he doesn't provide any other identifying information about this denomination.  It's possible that the following paragraph's contrast to the "Presbyterian church" indicates that the change was made in a non-presbyterian hymnal, but that's not definitive.  And this article was written in 1954, so the hymnal must have been published before then, but probably not long before.

Which denomination and hymnal is Clark likely referring to?
I don't have any particular knowledge of which hymnal Gordon Clark was referring to, but on a hunch, I consulted my copy of "Christian Science Hymns" [1952 Edition], edited by Mary Baker Eddy's successors, and find that the text of Holy, Holy, Holy included there has the modifications you cite. Stanzas one and three have as the final line of the stanza, "which wert, and art, and ever more shall be".

I don't have a copy of a Jehovah's Witness hymnal in my collection, and it is possible, if the text is included in that collection, that it has been similarly altered.