As attentive readers will already know, I’m currently reading John Rateliff’s two-volume History of The Hobbit, which I am reviewing for the next issue of Mythlore. In Rateliff’s short essay on Bard the Bowman and his Black Arrow, something caught my eye:
Once again Beowulf may have contributed something to the idea of a weapon that achieves its goal but then perishes: in the battle with Grendel’s dam, Beowulf [...] is able to slay her and to cut off Grendel’s head with an ancient sword he finds within her lair. This ealdsweord eotenisc ([...] literally ‘old entish sword’) then melts away [...], leaving only the hilt behind [...]. I’m not sure how apt is the comparison between this “old entish sword” and Bard’s Black Arrow, but it got me to thinking about two other melting blades in The Lord of the Rings. The first is the dagger of the Witch-king, which melts away after giving Frodo a near-fatal wound:
He [Strider] stooped again and lifted up a long thin knife. There was a cold gleam in it. As Strider raised it they saw that near the end its edge was notched and the point was broken off. But even as he held it up in the growing light, they gazed in astonishment, for the blade seemed to melt, and vanished like a smoke in the air, leaving only the hilt in Strider’s hand.The second is the sword of the Barrow-downs, with which Merry “dealt that foe a wound so bitter, cleaving the undead flesh, breaking the spell that knit his unseen sinews to his will.” But the blade perishes in the act (indeed, Aragorn has said long before that “all blades perish that pierce that dreadful King”):
Then he [Merry] looked for his sword that he had let fall; for even as he struck his blow his arm was numbed, and now he could only use his left hand. And behold! there lay his weapon, but the blade was smoking like a dry branch that has been thrust in a fire; and as he watched it, it writhed and withered and was consumed.Both scenes (of which Rateliff mentions only the second) remind one immediately of Beowulf, where we encounter this vivid description:
[...] // þa þæt sweord onganPretty powerful stuff, but was Tolkien deliberately echoing Beowulf in The Lord of the Rings, or was the allusion perhaps merely an unconscious one? After all, the melting sword motif is used of both an evil blade, then a good, an evil wielder, then an evil victim. Thanks to Wayne Hammond and Christina Scull’s Reader’s Companion, we have an excerpt from a previously unpublished letter in which Tolkien speaks directly to the point (no pun intended):
[Then that sword began]
æfter heaþoswate // hildegicelum,
[from the blood of war, the icicles of battle,]
wigbil wanian. // þæt wæs wundra sum,
[the war-blade to wane. That was a wondrous thing,]
þæt hit eal gemealt // ise gelicost,
[that it all melted just like ice]
ðonne forstes bend // fæder onlæteð,
[as when frosty bonds the Father releases,]
onwindeð wælrapas, // se geweald hafað
[unwinds the well-ropes, having wielded all]
sæla ond mæla; // þæt is soð metod.
[seasons and times: that is the true Lord.] 
The melting of the sword-blade has a dramatic quality, which is attractive to a storyteller and makes it linger in the memory; but the dramatic effect is the only real connexion between the different uses of the motif [in The Lord of the Rings ...] and the Anglo-Saxon poem. But that remains a fact of my personal biography (of which I was certainly not consciously aware when writing), and in no way enhances or explains the incidents in their places. What about Rateliff’s ‘literal’ translation “old entish sword”? Likewise, the sword is elsewhere called enta ærgeweorc , which Rateliff or I might translate “ent-wrought”. I like using “entish” here myself, but it could be a bit confusing unless one remembers that the Old English ent (also eten and eoten) was really just a Giant in the Germanic mythological tradition. In fact, *ent may be taken as the theorized form the Old English word(s) would have eroded into over the intervening centuries. In the long history of Beowulf translations, one often finds eotenisc rendered as “giant”, “giant-made”, “giant-wrought”, “gigantic” (which is not quite right), and so forth (a prodigious sampling can be examined here). But with the proper footnotes, “entish” might do just as well.
Compare Old English eoten with Old Norse jötunn “giant”, and Old English Eotaland “the land of the Jutes, Jutland” with Old Norse Jötunheimr, the World of the Giants in Norse mythology. Tolkien derived the name of his Ents from Anglo-Saxon literature , but we also find it used as more or less synonymous for Trolls in the toponym, Ettenmoors, the wild region north of Rivendell inhabited by the Ents’ more, well, trollish cousins. In fact, in early drafts, this area was called the “Entish Lands”. C.S. Lewis also used the toponym, Ettenmoor (singular), in his Chronicles of Narnia. Early on, Tolkien was unsure whether Treebeard the Ent would be friend or foe, or exactly what sort of giant he was (Gandalf “was caught in Fangorn and spent many weary days as a prisoner of the Giant Treebeard” ). But I digress. The point to take away from this is that Tolkien developed the idea of his Ents and Trolls (the two races are explicitly linked in some of the later “Silmarillion” writings) from this generalized notion of Giants in the Germanic mythological literature. One wonders whether they ought to be linked to the Stone-giants in The Hobbit as well.
It was just like Tolkien to postulate a feigned history for such a race (or races) of beings. Even so, one can’t easily imagine Tolkien’s Ents (or Trolls) wielding a sweord eotenisc ... And yet, the melting sword (unconsciously, it would seem) also found its way into Tolkien’s imagination.
 Rateliff, John D. The History of the Hobbit. Boston: Houghton Mifflin, 2007, p. 558–9.
 Beowulf, ll. 1605b–1611; the more or less literal translation, with any attendant faults, is mine.
 Hammond, Wayne G. and Christina Scull. The Lord of the Rings: A Reader’s Companion. Boston: Houghton Mifflin, 2005, p. 182.
 Beowulf, l. 1679.
 In addition to Beowulf, “ents” are found in the poem The Wanderer, to which Tolkien refers in his letter to W.H. Auden (#163): Carpenter, Humphrey, ed. The Letters of J.R.R. Tolkien. Boston: Houghton Mifflin, 1981, p. 212, 445n2.
 Tolkien, Christopher, ed. The Return of the Shadow: The History of The Lord of the Rings, Part One. Boston: Houghton Mifflin, 1988, p. 363.