perispomenon wrote:although I am not sure ας in θέμιστας is long or short (I chose long).
The recessive accent shows that the -ας is in fact short, otherwise the accent could not go farther back than the iota. Do your remember nominative sing. θάλασσα (short alpha in the ending) but accusative plur. θαλάσσας with the accent on the penult because the alpha became long (< *θαλασσα-νς).
Here we have the plural accusative from αἱ θέμιστες (3rd decl.), thus θέμιστας < *θεμιστ-νς has a short alpha.
With βασιλεύῃ, the verse would be unmetrical because the alpha is short. βουλεύῃσι fits better in, helping to make up a spondaic hexameter :
_ _ | _uu | _ u ' u | _uu | _ _ | _ _
In "I 99", "I" stands for "Iota upper case", i.e. "Iliad, Book number 9", since the 24 books of Iliad were designated by means of upper case Greek letters (Odyssey's books have lower case letters), so I 99 means Iliad, I-9, 99, that reads :
σκῆπτÏόν τ᾽ ἠδὲ θέμιστας, ἵνά σφισι βουλεύῃσθα.
But the manuscripts of the Iliad bear βασιλεύῃ, later corrected into βουλεύῃσι.
Hope this helps.