In The Mirror of Galadriel we encounter a passage that suggests, but does not define, a difference between 'Elf magic' and the sorcery of the Enemy:
'And you?' she said, turning to Sam. 'For this is what your folk would call magic, I believe; though I do not understand clearly what they mean; and they seem also to use the same word of the deceits of the Enemy. But this, if you will, is the magic of Galadriel. Did you not say that you wished to see Elf magic?'
'I did,' said Sam, trembling a little between fear and curiosity. 'I'll have a peep, Lady, if you're willing.'(FR 2.vii.362)
Yet the visions Sam and Frodo see in the mirror do not help to clarify the distinction Galadriel feels exists between the two forms of 'magic.' A section of On Fairy-Stories offers us some help here:
Turning back to The Lord of the Rings, we may now more easily see the 'deceits of the Enemy' and view Frodo's conversation with Galadriel in a more disturbing light:We need a word for this elvish craft, but all the words that have been applied to it have been blurred and confused with other things. Magic is ready to hand, and I have used it above ... but I should not have done so: Magic should be reserved for the operations of the Magician. Art is the human process that produces by the way (it is not its only or ultimate object) Secondary Belief. Art of the same sort, if more skilled and effortless, the elves can also use, or so the reports seem to show; but the more potent and specially elvish craft I will, for lack of a less debatable word, call Enchantment. Enchantment produces a Secondary World into which both designer and spectator can enter, to the satisfaction of their senses while they are inside; but in its purity it is artistic in desire and purpose. Magic produces, or pretends to produce, an alteration in the Primary World. It does not matter by whom it is said to be practised, fay or mortal, it remains distinct from the other two; it is not an art but a technique; its desire is power in this world, domination of things and wills.(OFS para. 75, emphasis mine)
'I would ask one thing before we go,' said Frodo, 'a thing which I often meant to ask Gandalf in Rivendell. I am permitted to wear the One Ring: why cannot I see all the others and know the thoughts of those that wear them?'
'You have not tried,' [Galadriel] said. 'Only thrice have you set the Ring upon your finger since you knew what you possessed. Do not try! It would destroy you. Did not Gandalf tell you that the rings give power according to the measure of each possessor? Before you could use that power you would need to become far stronger, and to train your will to the domination of others.(FR 2.vii.366)
I have discussed this conversation at length before, and mean to do so again once I have reflected further on what I have noticed here. Frodo is on a complex spiritual journey, as dappled with light and shadow as a wood in summer. We too often ignore the shadow within him because the light that at times shines from him is more comforting (FR 2.i.223; TT 4.iv.652). His interest in using the Ring to know the thoughts of others is a darkness that exists in tension with his offer a moment earlier to surrender the Ring to Galadriel. At the same time this 'technique' he desires to employ is also in tension with the 'art' he tries to practice in the poem he composes commemorating Gandalf earlier in this same chapter (FR 2.vii.359-60), his first use of poetry since being 'enchanted' by the art of elvish minstrelsy in Rivendell (FR 2.i.233).