Ruskin had in a sense laid the ground for both men [Pound & W. Lewis]: 'The art of any country,' he wrote in Modern Painters, 'is the exponent of its social and political virtues. The art, or general productive and formative energy, of any country is an exact exponent of its ethical life.'Nice quote, one I can use; the footnote reference is to the JR Library Edition, 2:38-9. Problem is Volume 2 of the Library Edition is "Poems." Modern Painters doesn't begin until volume 3; no such quotation on pp. 38-9, nor on 138-9, 238-9, etc.
Back in the day I'd be pitchforking thru stacks of books & papers, looking for somebody else's citation of this (after all rather famous & important) couple of sentences. In our brave new intertubes world, all I have to do is google up the first sentence, where I learn that it's not from Modern Painters at all, but Ruskin's inaugural Slade Professorship lecture at Oxford – the Library Edition's volume 20, that is, rather than volume 2.
(And the sentences in question are on page 39, not pp. 38-9, not to mention that there's another sentence in between 'em, not indicated by ellipses. Methinks Peter is doing the old "second-hand" quotation thing, scooping up the ripe bits from another book – in this case SueEllen Campbell's The Enemy Opposite: The Outlaw Criticism of Wyndham Lewis, also cited in his note. Something we've all done once in a while, I bet. Smashing good article, anyway.)