Chapter Electricity to Elf-arrows of E by Brewer's Phrase & Fable

Ghibelline, is mentioned in Johnson (article GOBLIN), though the words existed long before those factions arose. Heylin (in his Cosmography, p. 130) tells us that some supported that opinion in 1670. Skinner gives the same etymology.
   Red Elf. In Iceland, a person gaily dressed is called a red elf (raud âlfr), in allusion to a superstition that dwarfs wear scarlet or red clothes. (Nial's Sagas.) Black elves are evil spirits; white elves, good ones.

Elf-arrows Arrow-heads of the neolithic period. The shafts of these arrows were reeds, and the heads were pieces of flint, carefully sharpened, and so adjusted as to detach themselves from the shaft and remain in the wounded body. At one time they were supposed to be shot by elves at people and cattle out of malice or revenge.

"There every herd by sad experience knows
How, winged with fate, their elf-shot arrows fly,
When the sick ewe her summer food forgoes,
Or stretched on earth the heart-smit heifers lie."Collins: Popular Superstitions.