skjalli ‘than the membrane of an egg’: Cf. Gylf (SnE 2005, 19), which says that the water in the well of the norn Urðr er svá heiligt at allir hlutir þeir sem þar koma í brunninn verða svá hvítir sem hinna sú er skjall heitir, er innan liggr við eggskurn ‘is so holy that all those things which come there into the well become as white as the membrane which is called skjall, which lies within the eggshell’; cf. also skjallhvít lilja ‘the skjall-white lily’, Árni Gd 68/2IV. Some medieval philosophers, including Martianus Capella, William of Conches and Peter Abelard, used the membrane of the egg to represent the air in ‘cosmic egg’ models of the universe (see further Dronke 1974, 79-99, 154-66). Ms. 2845 reads skildi ‘shield’; the scribe may have been thinking of shields painted white or made from a light-coloured wood, references to which are not uncommon in Old Norse poetry. Cf. e.g. sciold hvítastan ‘the whitest shield’, Akv 7/9 (NK 241); hvítra skjalda ‘white shields’, Þhorn Harkv 8/2I and Note; Sigv Nesv 9/2, 3I and Note. On painted and decorated shields see Falk (1914b, 129-32, 145-8). The sunbeam in the solution is presumably the key to resolving this paradox, that the object can be both whiter than skjall and blacker than the raven, since obsidian has reflective properties.