Mysteries of the One Ring
Concerning the Tolkien article: The One Ring makes living tissue invisible by placing it “elsewhere” and the cut-off finger is no longer living. That’s why the One Ring doesn’t work on Frodo’s bitten-off dead finger. The One Ring makes beings that are not living and “elsewhere” and brings them “here.” The Eye is a portal through which power is expressed from “elsewhere,” but not fully because the nonliving being isn’t fully “here” with all his or her power. The One Ring is necessary to accomplish this and why it is sought after by Sauron. The One Ring isn’t about invisibility, but travel between “places.” If you wanted just invisibility, then you’d get an Elven cloak.