OER - Finding free ebooks

Stephen Downes is participating in an Oxford-style debate "Should OER favour commercial use?" He mentions "Flooding – this is the enclosure practice employed in the Google search results. It becomes impossible to find the original free resource when the market is flooded with commercial alternatives." Yes! Even at OpenLibrary), it feels like you have to knock yourself out to find an item that's available to anyone from any place. However I think I have a partial solution to the example that Downes uses - a quotation from Locke. I tried the search in Google Books - and clicked "free Google eBooks" from the search tools on the left side of the screen. That helps.