Merroe, it looks like we agree. One quibble:
Frodo was not using
Sting on
Weathertop. He had one of the
barrow-blades from
Tom Bombadil, as did the other three
hobbits: “it flickered red, as if it was a firebrand.” The
Witch-king broke this
sword at the Ford of Bruinen, when he and the other
Nazgûl tried to cross over to Frodo; all
Tolkien tells us is that the Witch-king “stood up menacing in his stirrups, and raised his hand. … [Frodo’s] sword broke and fell out of his shaking hand.” Regardless, though, you are correct: there is no mention of his companions on Weathertop seeing Frodo’s sword, though the Nazgûl certainly did!
With respect, we really don’t know for certain whether
Gollum could see Sting while
Bilbo was invisible or not. Bilbo “struck his toes on a snag in the floor, and fell flat with his little sword under him.” He sheathed the sword before following Gollum. What we can say is that Gollum could not see the sword
through him, even though it was “glowing faintly again.”
You assembled a fairly comprehensive list. There is one important instance you did not mention; your excellent list called it to mind. I’d like to ramble on about it for a while.
When the
Orcs at
Cirith Ungol found Frodo’s body,
Sam was still wearing
the Ring, which he put on when Gorbag’s company came over the crest of the pass in front of him. As he rushed down toward the Orcs when they took his master’s body, he said to himself, “‘They’ll see the flame of the sword as soon as I draw it,’” so he knew that once drawn, Sting – or at least its light – was not hidden by the Ring. He chased them as they entered
Shelob’s Lair carrying Frodo: “He drew the sword, a flicker of blue in his wavering hand, but they did not see it.” The Orcs weren’t looking at him, because he was behind them, of course: Shelob was the risk they feared, and she was somewhere ahead of them. Their failure to notice Sting was mundane: they’d have still failed to notice Sting were Sam visible and wearing a clown costume, because all their attention was focused on the dangerous passage past a monster that wanted to eat them.
Sam continued wearing the Ring while brandishing Sting as he re-entered
Torech Ungol. “It no longer seemed very dark to him in the tunnel, rather it was as if he had stepped out of a thin mist into a heavier fog.” That’s a remarkable statement, since earlier Tolkien described walking in Torech Ungol “as it were in a black vapor wrought of veritable darkness itself that, as it was breathed, brought blindness not only to the eyes but to the mind, so that even the memory of … any light faded out of thought.” Perhaps by escaping and defeating Shelob, Sam broke the spell that wove this uncanny darkness.
Somewhere along the way, he must have sheathed the sword, because at the door to the Underway into Cirith Ungol, “He drew his sword again and beat on the stone with the hilt… The sword … blazed so brightly … that he could see dimly in its light.” Unfortunately, we don’t know whether he was still wearing the Ring! I think he was, and I think Christopher Tolkien thinks he was, too: In
Reader’s Companion for page 898 (III: 174), Hammond and Scull write,
he drew out the Ring and put it on again – A reader pointed out to Christopher Tolkien that Sam put on the Ring at the end of Book IV, and now ‘put it on again’, but there is no intervening reference to him taking it off. Christopher Tolkien agreed that ‘this does seem to be a most remarkable case of the author nodding’ (Courtesy of Christopher Tolkien)
This phrase
Courtesy of Christopher Tolkien means Christopher Tolkien himself provided Hammond and Scull this citation from his correspondence, and that it was not elsewhere referenced at the time of publication.
I think Sam’s sheathing Sting was omitted after he re-entered the tunnel just as his taking off the Ring was omitted. Logically, it seems he should have been still wearing the Ring and carrying the sword when he came to the stone door blocking the Underway; otherwise, he should have run smack into it, because he was running as fast as he was still able (he hadn’t eaten for at least a day, and he’d been running all the way from the top of the pass trying to catch the Orcs), and even though the darkness of the tunnel appeared as a heavy fog, he had no light other than the sword. But since Tolkien subsequently says, Sam “drew his sword again,” that cannot be; and later, he “put [the Ring] on again”.
In any case, Sam knew the Orcs would see Sting when he drew it despite his wearing the Ring.