I would surmise that the swords glowed due to some (pardon the star trekky
word) multi-phased forging. That is, that the swords the Noldor forged operated
not only in the 'real' world, but also in the realm of Shadow. Just like
Glorfindel glowed in the shadow world-- which Fordo could see more clearly as
he was further infected by the Nazgul blade-- so also do Noldorin swords exist
in both worlds.
As such, and using 'elf-magic', which is just a way of describing the effects
elves have on the shadow world, the blades were forged to be sensitive to the
taint of Morgoth in the shadow world, thus reavealing the presence of orcs and
other servants of the Enemy.
As to your second question, I would again surmise that only swords forged by
the Noldorin smiths in Middle-Earth had any sort of capability in that regard--
as we see very few such examples of Noldorin craftsmanship, we don't know how
many swords operated in this manner. Fingolfin's sword, Ringil, shone with a
blue light like the stars, according to the Silmarillion, so it is likely that
the other swords the Noldor forged in the First Age had similar abilities.
As to Narsil, I can't recall any passages where it it said to shine-- although
Anduril does, after the reforging (again by Noldorin smiths in Rivendell). It's
not the same as Glamdring or Sting, but it does glow-- at least that is my
interpretation of this passage from FotR: "Very bright was that sword [Anduril]
when it was made whole again; the light of the sun shone redly in it, and the
light of the moon shown cold, and its edge was hard and keen."
One could argue that it was merely reflecting the light of sun and moon, but if
that were the case, why whould it shine 'redly' under the yellow light of the
sun? It seems to me that the sword had some ability to create its own light,
using the light of sun and moon as a catalyst. Feanor made gems that did the
same thing under the light of the stars of Varda-- they shone with their own
light, but only when exposed to starlight.
Inferno.
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tOR.N's Message Board Parody Collection (thanks to Gorel)
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